JP2011046484A - Paper feeder, automatic document conveyor and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce impact noise attributable to the descent of a movable arm with a simple constitution at low cost. <P>SOLUTION: A paper feeder 500 has a movable arm 504 with one end thereof being rockingly held by a feeder body, and a pickup roller 503 which is turnably mounted on a supporting shaft 503a arranged on the other end of the movable arm 504. The movable arm 504 is rocked in a drivable manner to an abutting state in which the pickup roller 503 is brought into contact with a paper sheet bundle 509, or to a non-abutting state in which the pickup roller 503 is not brought into contact with the paper sheet bundle 509. The pickup roller 503 is driven in the abutting state to take out sheet-like members one by one. A braking device 512 to which the resistant force is imparted to the rotation of the arm by the viscoelastic resistance is connected to the movable arm 504. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sheet feeder, an automatic document feeder, and an image forming apparatus, and more particularly, to a sheet feeder, an automatic document feeder, and an image forming apparatus including the sheet feeder that can reduce impact noise with a simple configuration. .

  Some sheet feeding devices include a pickup mechanism and a separation mechanism. As the pickup mechanism, there is one in which a movable arm provided with a pickup roller is swung so that the pickup roller is brought into contact with a sheet as required. Here, the movable arm is swung in order to insert a bundle of paper into a fixed paper base or to keep the arm out of the way when installing the paper tray. The sound may be generated by the driving.

  That is, in order to bring the pickup roller into contact with the paper, the movable arm is in a contact state (a state where the arm is lowered) from a state where the pickup roller and the paper are not in a contact state (a state where the arm is raised). When the movable arm is released, after the support mechanism of the movable arm is released, it is lowered toward the paper surface in a state where a tensile force is applied by a spring force or its own weight, and an impact force is generated when the movable arm comes into contact. Collision noise is generated.

  Further, when the sheet bundle is installed, the movable arm must be higher than the thickness of the sheet bundle so that the sheet bundle can be inserted. In this state, when a paper bundle having a thickness smaller than the maximum paper bundle thickness that can be installed in the paper feeding device is installed and the paper feeding operation is started, the lowering dimension of the arm becomes larger and the impact sound becomes larger accordingly. . Such a paper feeding device is used for supplying printing paper to a conveyance path and conveying a document to a reading device.

  Conventionally, there is a technique that suppresses the impact by reducing the distance between the pickup roller and the paper bundle before starting the paper feeding operation, but this technology can control the height of the paper base relative to the position where the movable arm is raised. This is effective for those that are controlled at a constant level regardless of the remaining number of sheets, but for those that have a fixed height, the sheet bundle thickness decreases as the paper feed proceeds. Therefore, it was impossible to reduce the impact noise beyond a certain level because a drop from a certain height was inevitable.

  In Patent Document 1, a release amount variable lever, a link having a long hole, and a solenoid plunger are connected to a release shaft of a release lever for retracting a pickup roller, and the release lever is rotated by turning on and off the solenoid. Change the moving angle so that the retraction amount for each sheet feeding operation of the pickup roller is smaller than the retraction amount for inserting and removing the paper cassette, and the retraction amount for each sheet feeding operation of the pickup roller. Is set to be as small as necessary, and as a result, the impact of the pick-up roller when the paper is pressed against the paper is reduced to suppress noise generation during the paper feeding operation.

Japanese Patent Application Laid-Open No. 2004-260688 discloses that a drawing roller abuts against a sheet at a sheet feeding position in order to feed the sheet paper stacked on the loading tray from the top. In order to be able to move to a standby position, a sheet feeding device is configured by providing a driving gear that is engaged with a fan-shaped gear that is integrally formed with an arm that supports an attracting roller and that is rotated by a stepping motor. There is a description that the speed is reduced, for example, the brake control is performed when the distance from the standby position to the position just before contacting the sheet is reached based on the distance measured by the distance measuring sensor disposed on the upper portion of the tray.

  However, the one described in Patent Document 1 adjusts the amount of movement of the movable arm with a solenoid, and the one described in Patent Document 2 uses a motor to move the movable arm up and down, and further to the paper. Since a distance measuring sensor is provided between them, both have a problem that the configuration is complicated and the cost is increased, and the control is also complicated.

  SUMMARY An advantage of some aspects of the invention is that it provides a sheet feeding device and an image forming apparatus including the sheet feeding device that can reduce the impact sound caused by the lowering of the movable arm with a simple configuration and at a low cost.

  The invention of claim 1 comprises a movable arm having one end swingably held by the apparatus body, and a pickup roller rotatably attached to a fulcrum shaft disposed at the other end of the movable arm, The contact state is such that the movable arm can be driven to a contact state in which the pickup roller contacts the stacked sheet-like member and a non-contact state in which the pickup roller does not contact the sheet-like member. In the sheet feeding device that drives the pickup roller to take out the sheet-like members one by one, the movable arm is connected to a braking device that applies a resistance force to the rotation of the arm by viscoelastic resistance. Is a sheet feeding device.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the movable arm includes a passive gear that receives a braking force from the braking device. The braking device includes an oil-type rotary damper, And a braking gear for transmitting the braking force of the rotary damper to the passive gear.

  According to a third aspect of the present invention, in the paper feeding device according to the first aspect, the movable arm includes a support mechanism that includes a passive gear that supports the movable arm on the device main body and receives a braking force from the braking device. The braking gear of the braking device is connected and transmits a braking force to the passive gear of the support mechanism.

  According to a fourth aspect of the present invention, in the paper feeding device according to any one of the first to third aspects, at least one of the meshing passive gear and the braking gear is free when the movable arm swings. In order to apply a braking force only at the position, it is characterized by including a tooth missing portion in which teeth are not formed around.

  According to a fifth aspect of the present invention, in the paper feeding device according to any one of the first to fourth aspects, the braking force of the rotary damper is greater than when the movable arm moves from a non-contact state to a contact state. The movable arm is set larger when it moves from the contact state to the non-contact state.

  According to a sixth aspect of the present invention, in the sheet feeding device according to any one of the first to fourth aspects, the rotary damper transmits a braking force when the movable arm moves from a contact state to a non-contact state. In other words, the movable arm is connected to the movable arm via a one-way clutch.

  According to a seventh aspect of the present invention, in the paper feeding device according to any one of the first to sixth aspects, the braking gear and the passive gear arranged in the rotary damper are not applied from the contact state of the movable arm. A predetermined amount of backlash is provided so as to operate without receiving the braking force of the oil damper when moving to the contact state.

  According to an eighth aspect of the present invention, there is provided an automatic document feeder comprising the paper feeding device according to any one of the first to seventh aspects.

  A ninth aspect of the present invention is an image forming apparatus comprising the paper feeding device according to any one of the first to seventh aspects or the automatic document feeder according to the eighth aspect.

  According to the present invention, since a simple configuration in which a rotary damper is disposed on the movable arm of the paper feeding device is adopted, the moving arm is lowered at a low cost, and the impact sound at the time of contact of the movable arm is reduced. can do.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment. FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device. It is a perspective view which shows the structure of the principal part of the paper feeder which concerns on an Example. FIG. 10 is a side view illustrating the operation of the sheet feeding device. It is a side view which shows the paper feeder which concerns on an Example. It is a side view which shows the paper feeder which concerns on a 2nd Example. It is a side view which shows the paper feeder concerning a 3rd Example. It is a perspective view which shows the paper feeder concerning a 4th Example.

  A sheet feeding device according to the present invention includes a movable arm having one end portion swingably held by the apparatus main body, and a pickup roller rotatably attached to a fulcrum shaft disposed at the other end of the movable arm. ing. Then, the movable arm is driven into a contact state in which the movable arm swings to contact the sheet-like sheet-like member on which the pickup roller is laminated and a non-contact state in which the pickup roller is not in contact with the sheet-like member. The sheet-shaped member is taken out one by one by driving the pickup roller in the contact state. The movable arm is connected to a braking device that applies a resistance force to the rotation of the arm by viscoelastic resistance.

  The movable arm of the sheet feeding device includes a passive gear that receives a braking force from the braking device. The braking device includes an oil-type rotary damper and a braking gear that transmits the braking force of the rotary damper to the passive gear. Can be provided.

  The movable arm of the sheet feeding device is connected to a support mechanism including a passive gear that supports the movable arm on the device main body and receives a braking force from the braking device, and the braking gear of the braking device is A braking force can be transmitted to the passive gear of the mechanism.

  In addition, at least one of the passive gear and the braking gear with which the sheet feeding device is meshed is a tooth having no teeth around it so that a braking force is applied only at an arbitrary position when the movable arm swings. A chip can be provided.

  Further, the braking force of the rotary damper of the sheet feeding device is larger when the movable arm moves from the contact state to the non-contact state than when the movable arm moves from the non-contact state to the contact state. Can be set.

  Further, the rotary damper of the sheet feeding device can be connected to the movable arm via a one-way clutch so that a braking force is not transmitted when the movable arm moves from the contact state to the non-contact state.

  In addition, the braking gear and the passive gear arranged in the rotary damper of the sheet feeding device operate without receiving the braking force of the oil damper when the movable arm moves from the contact state to the non-contact state. A predetermined amount of backlash can be provided.

  Further, the paper feeding device can be applied to an automatic document conveying device that conveys a document to a document reading unit in addition to conveying printing paper. The image forming apparatus according to the present invention can include the automatic document feeder in addition to the conveyance of the recording medium using the paper feeder.

  Hereinafter, an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment, and FIG. 2 is a cross-sectional view illustrating a configuration of a fixing device. The image forming apparatus main body 100 according to the present example includes a sheet feeding device 300 including the sheet feeding device according to the embodiment and a manual sheet feeding unit 73.

  The image forming apparatus includes an image reading apparatus 200 on the image forming apparatus main body 100, and the image forming apparatus main body 100 and the image reading apparatus 200 are mounted on a table-shaped paper feeding apparatus 300. An automatic document feeder 400 is disposed on the image reading device 200 so as to be freely opened and closed.

  The image forming apparatus main body 100 includes a drum-shaped photoconductor 10 as an image carrier inside. A charging device 11 is arranged on the left side in the drawing around the photoconductor 10, and along the rotation direction of the photoconductor 10 (counterclockwise direction: arrow A in the drawing), the developing device 12, the transfer device 13, and the cleaning device 14. Is arranged. The transfer device 13 is configured by winding a transfer belt 17 between upper and lower rollers 15 and 16, and presses the transfer belt 17 against the peripheral surface of the photoconductor 10 at the transfer position B.

  A toner replenishing device 20 that replenishes new toner to the developing device 12 is disposed on the left side of the charging device 11 and the cleaning device 14 in the drawing. Further, inside the image forming apparatus main body 100, a sheet conveying apparatus C is arranged that feeds a sheet such as a sheet or an OHP sheet from a supply position (to be described later) and conveys the sheet to the stack position via the transfer position B. The sheet transport apparatus C includes a supply path R1, a manual feed path R2, and a sheet transport path R, which will be described later. The sheet conveying path R has a substantially L-shape that passes between the photosensitive member 10 and the transfer device 13 and extends from the bottom to the top in the drawing and then turns to the left.

  In the sheet conveyance path R, a registration roller 21 is disposed at an upstream position of the photoconductor 10. Further, a fixing device 22 is disposed at a downstream position of the photoconductor 10. As shown in FIG. 2, the fixing device 22 includes a pair of fixing rollers (fixing roller rotating bodies) 24a and 24b. A fixing heater 23 is disposed inside one fixing roller 24a, and a pressure spring 25 and a pressure arm 26 are disposed around the other fixing roller 24b. The other fixing roller 24 b is pressed against one fixing roller 24 a by the pressure spring 25 and the pressure arm 26. Further, a thermistor 28 and a thermostat 29 are arranged on one fixing roller 24a.

  Then, while the temperature of the fixing roller 24a is measured by the thermistor 28, the fixing roller 24a is kept at a predetermined temperature by turning on or off the fixing heater 23 by the thermostat 29.

  Further downstream of the fixing device 22, a discharge branch claw 34, a discharge roller 35, a first pressure roller 36, a second pressure roller 37, and a waist roller 38 are arranged. A discharge stack portion (discharge position) 39 to be stacked is arranged.

  The image forming apparatus main body 100 includes a switchback device 42 on the right side in the drawing. The switchback device 42 branches from the discharge branch claw 34 position of the sheet conveyance path R and leads to the switchback position 44 including the pair of switchback rollers 43, and the sheet conveyance path R again from the switchback position 44. A sheet conveying apparatus D having a re-conveying path R4 that leads to the registration roller 21. In addition, the sheet conveying apparatus D includes a plurality of sheet conveying rollers 66 (sheet conveying rotating bodies) that convey the sheet.

  On the left side of the developing device 12 in the figure, a laser writing device 47 is arranged. The laser writing device 47 includes a laser light source (not shown), a scanning rotary polygon mirror 48, a polygon motor 49, a scanning optical system 50 such as an fθ lens, and the like. The image reading apparatus 200 includes a light source 53, a plurality of mirrors 54, an imaging optical lens 55, an image sensor 56 such as a CCD, and a contact glass 57 is disposed on the upper surface.

  The automatic document feeder 400 disposed on the contact glass 57 includes a document mount (not shown) at the document placement position, a discharge table (not shown) at the discharge position, and a sheet such as a document. A sheet conveyance device having a document conveyance path (not shown) that conveys from the table to a discharge table through a reading position on the contact glass 57 of the image reading device 200 is provided. The sheet conveying apparatus includes a plurality of sheet conveying rollers (sheet conveying rotating bodies) (not illustrated) that convey a sheet such as a document.

  The sheet feeding device 300 includes therein a plurality of sheet separating devices 61 serving as sheet S supply positions. Each paper separation device 61 includes a pickup roller 62 (feed roller), a feed roller 63 (feed roller), and a reverse roller 64 (separation roller) correspondingly. A supply path R1 leading to the sheet conveyance path R of the image forming apparatus main body 100 is formed on the right side of the sheet separating apparatuses 61 arranged in multiple stages in the drawing. The supply path R1 includes a number of sheet transport rollers 66 (sheet transport rotating body) for transporting the sheet.

  In the image forming apparatus main body 100, a manual paper feed unit 73 is disposed on the right side in the drawing. The manual sheet feeding unit 73 includes a manual feed tray 67 (supply position) that can be freely opened and closed, and a manual feed path R2 that guides a manual sheet set on the manual feed tray 67 to the sheet conveyance path R. The manual feed tray 67 includes a pickup roller 62 (feed roller), a feed roller 63 (feed roller), and a reverse roller 64 (feed roller).

  To generate a copy using this copying machine, a main switch (not shown) is turned on and a document is set on the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set directly on the contact glass 57 of the image reading device 200, and the automatic document feeder 400 is closed and pressed.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is moved on the contact glass 57 through the document conveyance path by the sheet conveyance roller, and then the image reading device 200 is moved. Drives, reads the contents of the document, and discharges it on the discharge table. On the other hand, when the document is set directly on the contact glass 57, the image reading apparatus 200 is immediately driven.

  When the image reading apparatus 200 is driven, the image reading apparatus 200 moves the light source 53 along the contact glass 57, reflects light from the light source 53 on the original surface on the contact glass 57, and reflects the reflected light to a plurality of light sources 53. The light is reflected by a mirror 54, passes through an imaging optical lens 55, is put in an image sensor 56, and the image content is read by the image sensor 56.

  At the same time, the photoconductor 10 is rotated by a photoconductor drive motor (not shown). First, in the illustrated example, the surface is uniformly charged by the charging device 11 using a charging roller, and then the above-described image reading device 200 is used. The laser writing device 47 irradiates a laser beam in accordance with the content of the read document and writes it with the laser writing device 47 to form an electrostatic latent image on the surface of the photosensitive member 10. Visualize the electrostatic latent image.

  At the same time when the start switch is pressed, the sheet S is sent out by the pickup roller 62 from the corresponding paper separating device 61 in the plurality of paper separating devices 61 provided in multiple stages in the paper feeding device 300, and the subsequent feed roller 63, reversing Each sheet is separated one by one by the roller 64 and is fed into the supply path R1 while being conveyed, conveyed by the sheet conveying roller 66 to the sheet conveying path R, and abutted against the registration roller 21 and stopped. Then, the registration roller 21 is rotated in synchronization with the rotation of the image visualized on the photoreceptor 10 described above, and is sent to the right side of the photoreceptor 10.

  Alternatively, the manual feed tray 67 of the manual feed unit 73 is opened, the manual sheet set on the manual feed tray 67 is sent out by the pickup roller 62, and separated and conveyed one by one by the subsequent supply roller 63 and separation roller 64. The sheet is then fed into the manual feed path R2, conveyed by the sheet conveying roller 66 to the sheet conveying path R, and similarly sent by the registration roller 21 to the right side of the photosensitive element 10 in time with the rotation of the photosensitive element 10.

  Next, the image on the photoconductor 10 is transferred to the sheet S fed to the right side of the photoconductor 10 at the transfer position B by the transfer device 13 having the transfer belt 17 to form an image. Residual toner on the photoconductor 10 after image transfer is removed and cleaned by a cleaning device 14, and a residual potential on the photoconductor 10 is removed by a neutralization device (not shown) to prepare for the next image formation starting from the charging device 11. .

  On the other hand, the sheet S after the image transfer is conveyed by the transfer belt 17 and passed between the pair of fixing rollers 24 a and 24 b of the fixing device 22, and heat and pressure are applied thereto to fix the transferred image by the fixing device 22. . Thereafter, the sheet is seated by the discharge roller 35, the first pressure roller 36, the second pressure roller 37, and the waist roller 38, discharged onto the discharge stack portion 39, and stacked there.

  Note that the discharge branch claw 34 is switched when images are transferred to both sides of the sheet. Then, the sheet with the image transferred on the surface is put from the sheet transport path R to the reverse path R3, transported by the sheet transport roller 66, put into the switchback position 44, switched back at the switchback position 44, and then restarted. The sheet is reversed into the conveyance path R4, conveyed by the sheet conveyance roller 66, guided again to the sheet conveyance path R, and the image is transferred to the back surface of the sheet in the same manner as described above.

  Next, the configuration of the paper feeding device 500 disposed in the paper feeding device 300 and the manual paper feeding unit 73 will be described. In the following description, the feed roller 63 will be described as a feed roller 501, the reverse roller 64 as a reverse roller 502, and the pickup roller 62 as a pickup roller 503. The paper feeding device 500 can also be applied to the automatic document feeder 400.

  FIG. 3 is a perspective view illustrating a main part of the sheet feeding device according to the embodiment. The paper feeding device 500 includes a feed roller 501 and a reverse roller 502 that separate paper sheets one by one, and a pickup roller 503 as a preliminary paper feeding mechanism that feeds the paper between the feed roller 501 and the reverse roller 502. The pickup roller 503 is rotatably disposed on a support shaft 503a disposed on one side of the movable arm 504, and the other side of the movable arm 504 is a swing shaft 504a fixed to the apparatus main body side (see FIG. 4). Is attached to be swingable. The pickup roller 503 is configured to be linked to the feed roller 501 via an idler gear 505, and rotates in synchronization with the rotation of the feed roller 501. The movable arm 504 swings downward about the swing shaft 504a so that the pickup roller 503 contacts the sheet bundle 509 ((A) in FIG. 4) and the separated non-contact position (same as above). (B)). Then, the feed roller 501 is rotationally driven with the pickup roller 503 in the contact position, the feed roller 501 and the pickup roller 503 are rotated at the same feed speed, and the sheets from the sheet bundle are sequentially sent out. When the pickup roller 503 does not need to be fed, the movable arm 504 is swung upward to control the paper feeding interval and function as an auxiliary transport mechanism for paper that is difficult to feed such as thick paper. The reversing roller 502 is rotated independently in the direction opposite to the conveying direction via a torque limiter, thereby separating the paper.

  A contact spring 506 is attached to the movable arm 504, and urges the movable arm 504 in the contact direction (downward direction). While the support mechanism 507 is locked to the movable arm 504, the swing of the movable arm 504 due to the urging force of the contact spring 506 is suppressed, but when the support mechanism 507 is released, the contact spring is brought into contact with the movable arm 504. The urging force of 506 acts and the movable arm 504 swings so as to be in a contact state.

  The support mechanism 507 is configured to include a pressing arm 507a, a plunger-type solenoid 507b, and a pulling spring 507c. When no current is applied to the solenoid 507b, the pressing arm 507a is moved to the movable arm 504 by the pulling spring 507c. The movable arm 504 is prevented from swinging. When driving power is applied to the solenoid 507b, the plunger is attracted and the pressing arm 507a moves away from the movable arm 504. The movement of the pressing arm 507a by applying a current to the solenoid 507b and the urging of the movable arm 504 by the contact spring 506 are performed independently.

  Next, the operation of the paper feeding device 500 in the paper feeding device 300 will be described. FIG. 4 is a side view showing the operation of the paper feeding device according to the first embodiment, and FIG. 5 is a side view showing the configuration of the paper feeding device. A sheet bundle 509 is installed on the sheet table 508, and the movable arm 504 is configured to be swingable. That is, the movable arm 504 is in a state in which the pickup roller 503 disposed at the tip does not contact the sheet (non-contact position: broken line (A) in the drawing), and the support mechanism 507 is released and the movable arm 504 is in contact with the spring. The pickup roller 503 is driven to abut against the sheet by the urging force 506 (contact position: (solid line (b))).

  As shown in FIG. 5, a braking device 512 is disposed in the paper feeding device 500. The braking device 512 includes an oil-type rotary damper 512a that generates a braking force by viscous resistance, and a braking gear 512b attached to the rotary shaft of the rotary damper 512a. The braking gear 512b is configured as the movable arm. The arm gear 511 which is a passive gear fixed concentrically with the swing shaft 504a of the shaft 504 is meshed. Therefore, a braking force is applied by the braking device 512 when the movable arm 504 is swung.

  According to this example, when the support mechanism 507 of the movable arm 504 is released, the movable arm 504 starts swinging, and the rotary damper 512a rotates accordingly, and the movable arm 504 is braked by the rotary damper 512a. While swinging, the rotation speed is suppressed. When the pickup roller 503 contacts the sheet bundle 509, the swinging of the movable arm 504 and the rotation of the rotary damper 512a are stopped, and the force of the contact spring 506 is transmitted to the sheet to feed the sheet. For this reason, in this example, the swinging speed of the movable arm 504 is suppressed, the impact when the movable arm 504 stops is mitigated, and noise at the time of collision can be reduced.

  Next, a paper feeder according to a second embodiment will be described. FIG. 6 is a side view showing a sheet feeding device according to the second embodiment. In this example, the braking device 513 includes an oil-type rotary damper 513a and a braking gear 513b disposed on the shaft of the rotary damper 513a. In this embodiment, the braking gear 513b includes a tooth missing portion 513c in which teeth are not formed around the brake gear 513b, so that the braking force of the rotary damper 513a is not transmitted to the arm gear 511 at the tooth missing portion 513c of the braking gear 513b. ing. That is, the tooth missing portion 513 c prevents the arm gear 511 from being located at the tooth missing portion 513 c so that the braking force of the braking device 513 is not transmitted to the movable arm 504 when the pickup roller 503 is disposed at a position away from the sheet bundle 509. On the other hand, the brake gear 513b immediately before the pickup roller 503 comes into contact with the sheet bundle 509 and the arm gear 511 mesh with each other to apply the braking force of the braking device 513 to the movable arm 504. According to the present embodiment, quick operation of the movable arm 504 and reduction of impact sound can be achieved.

  Next, a paper feeder according to a third embodiment will be described. FIG. 7 is a side view showing a paper feeding apparatus according to the third embodiment. In the paper feeding device 500 according to this example, the rotary damper 514a of the braking device 514 is connected to the braking gear 514b via the one-way clutch 515. The one-way clutch 515 transmits the braking force only in the contact direction of the movable arm 504 (arrow A direction in the figure) and does not transmit the braking force in the non-contact direction of the movable arm 504 (counter A direction in the figure). According to this example, the movable arm 504 can be operated quickly, and the total operation time can be shortened. It should be noted that the rotary damper itself has unidirectionality, that is, when the movable arm moves from the non-contact state to the contact state, the movable arm moves from the non-contact state to the non-contact state. The same effect can be obtained by setting a larger value when moving to.

  Next, a paper feeder according to a fourth embodiment will be described. FIG. 8 is a perspective view showing a paper feeder according to the fourth embodiment. The sheet feeding device 500 according to the present example has a rotary damper 516 disposed on the side of the pressing arm 507a of the support mechanism 507, and directly brakes the movement of the solenoid 507b, thereby obtaining the same operation as in the above embodiments. . According to this example, the impact sound can be reduced with a more compact configuration as in the above examples.

  Next, a fifth embodiment will be described. In the paper feeding device according to this example, the backlash of the arm gear 511 and the braking gear 512b of the paper feeding device 500 shown in FIG. 4 is set to a predetermined size. That is, when the movable arm 504 is driven from the contact state to the non-contact state, the joining of the two gears 511 and 512b is delayed by the backlash of both the gears 511 and 512b, and the initial predetermined state in which the shift to the non-contact state is performed. This prevents the braking force of the braking device 512 from acting on the movable arm 504 during the period. In this embodiment, the movable arm 504 is driven without a braking force, so that the pickup roller can be reliably and quickly separated from the paper, and unnecessary feeding can be prevented.

  As described above, according to the paper feeding device according to the present invention, when the movable arm comes into contact, a braking force is applied by the braking device, the swing speed is suppressed, the impact is reduced, and the noise is reduced. can do. Further, since the paper feeding device according to the present invention uses an oil-type rotary damper, the movable arm becomes non-rotating after the pickup roller contacts the paper, and the resistance torque is lowered due to the characteristic of the rotary damper. Therefore, it is not necessary to greatly increase the spring force adjusted with a predetermined contact pressure. Furthermore, the oil-type rotary damper can suppress a decrease in bounce at the time of contact, which is likely to occur in a spring type or a pneumatic type, and can reliably maintain the contact state.

  Here, in the sheet feeding device according to the present invention, the swing of the movable arm is performed via a damper. For this reason, a difference occurs in the time required for the rotation operation depending on the presence or absence of the damper. In order to release the support mechanism so that the movable arm makes the pickup roller contact the sheet bundle at a target timing, it cannot be performed with the same timing control as that without the damper. This is because when there is a damper, the rotation speed is slowed down as much as the load is received, and a delay occurs in contact. However, this can be solved by releasing the support mechanism at a certain early timing as compared with the case where there is no damper.

  Although a device that simply applies a friction load can be used as the braking device, the load remains even at the time of contact, and the urging force of the spring is attenuated.

DESCRIPTION OF SYMBOLS 10 Photoconductor 11 Charging device 12 Developing device 12b Braking gear 13 Transfer device 14 Cleaning device 15, 16 Roller 17 Transfer belt 20 Toner replenishing device 21 Registration roller 22 Fixing device 23 Fixing heater 24a, 24b Fixing roller (fixing roller rotating body)
25 pressure spring 26 pressure arm 28 thermistor 29 thermostat 34 discharge branch claw 35 discharge roller 36 first pressure roller 37 second pressure roller 38 waist roller 39 discharge stack portion (discharge position)
42 switchback device 43 switchback roller 44 switchback position 47 laser writing device 48 rotary polygon mirror 49 polygon motor 50 scanning optical system 53 light source 54 mirror 55 imaging optical lens 56 image sensor 57 contact glass 61 paper separating device 62 pickup Roller 63 Feed roller (supply roller)
64 Reversing roller
66 Sheet transport roller 67 Manual feed tray 73 Manual paper feed unit 100 Image forming apparatus main body 200 Image reading device 300 Paper feed device 400 Automatic document transport device 500 Paper feed device 501 Feed roller 502 Reversing roller 503a Support shaft 503 Pickup roller 504 Movable arm 504a Oscillating shaft 505 Idler gear 506 Contact spring 507 Support mechanism 507a Press arm 507b Solenoid 507c Pulling spring 508 Paper base 509 Paper bundle 511 Arm gear (passive gear)
512 Braking device 512a Rotary damper 512b Braking gear 513 Braking device 513a Oil type rotary damper 513b Braking gear 513c Tooth missing part 514 Braking device 514a Rotary damper 514b Braking gear 515 Rotary damper 516 Rotary damper

Japanese Patent Application Laid-Open No. 07-025495 Japanese Patent Laid-Open No. 08-295427

Claims (9)

A movable arm having one end swingably held by the apparatus main body, and a pickup roller rotatably attached to a fulcrum shaft disposed at the other end of the movable arm, and swinging the movable arm The pickup roller can be driven to a contact state in which the pickup roller is in contact with the laminated sheet-like member and a non-contact state in which the pickup roller is not in contact with the sheet-like member, and the pickup roller is driven in the contact state. In the paper feeding device for taking out the sheet-like members one by one,
The movable arm is connected to a braking device for applying a resistance force to the rotation of the arm by viscoelastic resistance. The movable arm includes a passive gear that receives a braking force from the braking device,
The sheet feeding device according to claim 1, wherein the braking device includes an oil-type rotary damper and a braking gear that transmits a braking force of the rotary damper to the passive gear. The movable arm is connected to a support mechanism including a passive gear that supports the movable arm on the apparatus main body and receives a braking force from the braking device.
The sheet feeding device according to claim 1, wherein the braking gear of the braking device transmits a braking force to the passive gear of the support mechanism.   At least one of the meshing passive gear and the braking gear includes a tooth-missing portion in which teeth are not formed so that a braking force is applied only at an arbitrary position when the movable arm swings. The paper feeding device according to claim 1, wherein the paper feeding device is a paper feeding device.   The braking force of the rotary damper is set to be larger when the movable arm moves from the contact state to the non-contact state than when the movable arm moves from the non-contact state to the contact state. The sheet feeding device according to claim 1, wherein   The rotary damper is connected to the movable arm via a one-way clutch so that a braking force is not transmitted when the movable arm moves from a contact state to a non-contact state. The paper feeding device according to claim 4.   The braking gear and the passive gear arranged in the rotary damper have a predetermined amount of backlash so that they operate without receiving the braking force of the oil damper when the movable arm moves from a contact state to a non-contact state. The sheet feeding device according to claim 1, further comprising: a sheet feeding device according to claim 1.   An automatic document feeder comprising the paper feeder according to any one of claims 1 to 7.   An image forming apparatus comprising the paper feeding device according to claim 1 or the automatic document feeder according to claim 8.