JP2010076912A - Paper feeder and image forming device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeder can perform excellent sheet conveyance to an image forming part without causing increase in power consumption even when a sheet having high surface smoothness is used, and to provide an image forming device equipped with this. <P>SOLUTION: A paper-feeding unit 130 is equipped with a control part 300. Until delay of conveyance time of a sheet P is detected by a delay detection part 82, the control part 300 controls to carry out normal-time driving in which driving of a pair of primary paper feeding rollers 41, 42 is stopped during the paper-feeding by driving of a pair of secondary paper feeding rollers 44, 45. After the delay of the conveyance time is detected by the delay detection part 82, the control part 300 controls to carry out dealing-with-delay driving in which the primary paper feeding rollers 41, 42 are driven during the paper-feeding by driving of the secondary paper feeding rollers 44, 45. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a paper feeding device used in an image forming apparatus such as a printer, a copier, a facsimile machine, or a multi-function machine having these functions in combination, and an image forming apparatus having the same.

  Conventionally, in image forming apparatuses such as printers, copiers, and facsimiles, sheet-like recording media that can be continuously fed are usually limited to high-quality paper and cut sheets such as plain paper designated by the copier manufacturer. It was.

  However, in recent years, sheet-shaped recording media have been diversified, and only sheets with low surface smoothness such as high-quality paper and plain paper are not used. In particular, with the development of color technology for image forming devices, coated paper with improved whiteness and glossiness (a coating color, a type of paint, is applied to both sides or one side of the sheet for the purpose of improving printability) A material having a high surface smoothness, such as a coated composite sheet), which is coated with a large amount of filler on its surface has been used. That is, in recent years, not only high-quality paper and plain paper, but also the above-mentioned coated paper, as well as film sheets, tracing paper, and the like, there is an increasing demand for conveyance by the same model.

Here, if the sheet feeding with a high surface smoothness as described above is continued, slip is likely to occur in each sheet feeding roller used in the sheet conveyance path to the image forming unit. For this reason, when the sheet is sent to the image forming unit, the primary paper feed roller provided on the downstream side in the sheet conveyance direction of the pickup roller and the secondary paper supply provided on the downstream side in the sheet conveyance direction of the primary paper feed roller. 2. Description of the Related Art Conventionally, a paper feeding device configured to drive both paper rollers has been used.
JP 2005-15100 A

  However, in the conventional configuration in which both the primary sheet feeding roller and the secondary sheet feeding roller are always driven from the start of sheet conveyance to convey the sheet to the image forming unit, consumption of the motor that drives the sheet feeding roller There is a problem that electric power becomes large.

  The present invention has been made in view of the above circumstances, and avoids the problem of sheet conveyance delay due to roller slip without causing an increase in power consumption even when a sheet having high surface smoothness is used. It is an object of the present invention to provide a paper feeding device that can realize good sheet conveyance to an image forming unit and an image forming device including the same.

  A sheet feeding device according to one aspect of the present invention is a sheet feeding device used in an image forming apparatus including an image forming unit, and is configured to feed a sheet-like recording medium fed from a sheet storage unit along a predetermined conveyance path. A primary sheet feeding mechanism that conveys the sheet-like recording medium that is provided downstream of the primary sheet feeding mechanism in the sheet conveying direction and conveys the sheet-like recording medium conveyed by the primary sheet feeding mechanism to the image forming unit 2 Until the leading edge of the sheet-like recording medium conveyed by the secondary paper feeding mechanism and the secondary paper feeding mechanism reaches a predetermined passing point in the conveyance path between the secondary paper feeding mechanism and the image forming unit. A delay detection unit that detects a delay in the transport time, and driving of the primary paper feed mechanism during feeding by the driving of the secondary paper feed mechanism until the delay of the transport time is detected by the delay detection unit. While the normal time drive is stopped, the delay detection unit After the transport time delay is detected, the primary paper feed mechanism and the primary paper feed mechanism are driven so that the primary paper feed mechanism is driven even during paper feed by the drive of the secondary paper feed mechanism. And a control unit that controls driving of the secondary sheet feeding mechanism.

  According to the above configuration, when the sheet-like recording medium is transported without delay, the normal driving is performed to stop the driving of the primary paper feeding mechanism during paper feeding by the driving of the secondary paper feeding mechanism. On the other hand, if a delay in the transport time until reaching a predetermined passing point in the transport path between the secondary paper feed mechanism and the image forming unit is detected, the secondary paper feed mechanism is driven. Control is performed so as to perform driving at the time of delay for driving the primary paper feeding mechanism even during paper feeding. For this reason, it is possible to appropriately switch between the normal time driving and the delay time driving in accordance with the state of conveyance of the sheet-like recording medium to the image forming unit. As a result, for example, even when a sheet with high surface smoothness is used, the problem of delay in sheet conveyance due to roller slip is avoided without causing a wasteful increase in power consumption. Therefore, it is possible to realize a sheet feeding device capable of realizing a proper sheet conveyance.

  In the above-described configuration, the image forming apparatus further includes a conveyance switch that detects that a leading edge of the sheet-like recording medium has reached the secondary paper feeding mechanism, and the control unit causes the leading edge of the sheet-like recording medium to be moved by the conveyance switch. When detected, when stopping the primary paper feed mechanism and also temporarily stopping the secondary paper feed mechanism with the leading edge of the sheet-like recording medium being sandwiched, In the case where the sheet-like recording medium is conveyed to the image forming unit by driving the secondary paper feeding mechanism, and when the driving at the time of delay is performed, the primary paper feeding mechanism and the secondary paper feeding mechanism drive the A configuration may be adopted in which the sheet-like recording medium is conveyed to the image forming unit.

  According to the above configuration, switching between the normal driving and the delay driving is performed at a timing when the conveyance switch that detects that the leading edge of the sheet-like recording medium has reached the secondary paper feeding mechanism is turned on. It can be performed.

  In the above configuration, the apparatus further includes a passing point switch provided at the passing point and detecting that the leading end of the sheet-like recording medium has reached the passing point, and the delay detecting unit includes a leading end of the sheet-like recording medium. A timer for measuring a predetermined delay determination time after detection by the conveyance switch is provided, and the leading edge of the sheet-like recording medium is detected by the passage point switch even when the timer completes the predetermined delay determination time. If not, it is desirable to detect a delay in the conveyance time of the sheet-like recording medium.

  According to the above configuration, the passing point switch that detects that the leading edge of the sheet-like recording medium has reached a predetermined passing point in the transport path between the secondary paper feeding mechanism and the image forming unit, and the sheet Using a timer that counts a predetermined delay determination time after the leading edge of the recording medium is detected by the transport switch, the delay detection unit, even if the timer completes timing of the predetermined delay determination time, When the leading edge of the sheet-shaped recording medium is not detected by the passing point switch, a delay in the conveyance time of the sheet-shaped recording medium can be detected and switched to the driving at the time of the delay.

  In the above configuration, it is desirable to perform control so that the normal driving is performed after the delay detection unit does not detect a delay in the conveyance time while the delay driving is continuously controlled. (Claim 4).

  According to the above configuration, when the delay of the transport time is detected by the delay detection unit and the transport time delay is not detected continuously for a predetermined number of sheets thereafter, even after switching to the driving at the time of delay. The drive is switched to normal driving again. This reduces waste of power consumption once compared to a configuration in which driving after delay is continued after switching to driving at delay, regardless of whether or not subsequent conveyance is performed well without delay. Can do.

  An image forming apparatus according to another aspect of the present invention includes the sheet feeding device having the above-described configuration and an image forming apparatus main body that forms an image on a sheet-like recording medium fed from the sheet feeding device. (Claim 5).

  According to the above configuration, a sheet feeding device that can avoid the problem of delay in sheet conveyance due to roller slip without causing a wasteful increase in power consumption and realize good sheet conveyance to the image forming unit. It has. Thereby, for example, even when a sheet having high surface smoothness is used, the sheet-shaped recording medium is excellent without causing a delay in image formation timing while reducing the increase in power consumption of the entire image forming apparatus. Therefore, it is possible to realize an image forming apparatus that can be transported to the surface.

  According to the present invention, even when a sheet having a high surface smoothness is used, the problem of delay in sheet conveyance due to roller slip is avoided without causing an increase in power consumption, and the image forming unit is improved. It is possible to provide a sheet feeding device capable of realizing sheet conveyance and an image forming apparatus including the sheet feeding device.

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

<First Embodiment>
With reference to FIG. 1 and FIG. 2, an image forming apparatus including a sheet feeding device according to an embodiment of the present invention will be described.

  FIG. 1 is a perspective view illustrating an appearance of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the internal structure of the image forming apparatus.

  As shown in FIG. 1, a color printer 1 as an image forming apparatus according to an embodiment of the present invention includes a printer main body 200 connected directly to a personal computer (PC) (not shown) or the like via a LAN, A sheet supply unit 100 is provided below the printer main body 200 and configured to store sheets P of various sizes according to the sizes. The color printer 1 also includes other components provided in a general color printer, such as a control circuit that controls the operation of the color printer 1.

  As shown in FIG. 2, the printer main body 200 includes toner containers 900Y, 900M, 900C, and 900K, an intermediate transfer unit 92, an image forming unit (image forming unit) 93, an exposure unit 94, a sheet supply unit 100, a fixing unit 97, A paper discharge unit 96, a housing 90 of the apparatus main body, a top cover 911, and a front cover 912 are provided.

  The image forming unit 93 includes a yellow toner container 900Y, a magenta toner container 900M, a cyan toner container 900C, and a black toner container 900K. 10K.

  The image forming unit 93 is further provided with a photoreceptor drum 17 (a photoreceptor on which a latent image is formed by an electrophotographic method) that carries toner images of respective colors. As the photoreceptor drum 17, a photoreceptor drum using an amorphous silicon (a-Si) material can be used. Each photosensitive drum 17 is supplied with yellow, magenta, cyan, and black toner from the corresponding toner containers 900Y, 900M, 900C, and 900K.

  Note that the image forming unit 93 of the present embodiment is configured to form a full-color image as described above, but is not limited thereto, and is configured to form a monochrome image or a color image that is not full-color. It may be.

  Around the photosensitive drum 17, a charger 16, a developing device 10 (10Y, 10M, 10C, 10K), a transfer device (transfer roller) 19, a cleaning device 18 and the like are arranged. The charger 16 uniformly charges the surface of the photosensitive drum 17. The surface of the photosensitive drum 17 after charging is exposed by the exposure unit 94 to form an electrostatic latent image. The developing devices 10Y, 10M, 10C, and 10K develop the electrostatic latent images formed on the respective photosensitive drums 17 using the toners of the respective colors supplied from the toner containers 900Y, 900M, 900C, and 900K, respectively ( Visualization). The transfer roller 19 forms a nip portion with the photosensitive drum 17 across the intermediate transfer belt 921, and primarily transfers the toner image on the photosensitive drum 17 onto the intermediate transfer belt 921. The cleaning device 18 cleans the peripheral surface of the photosensitive drum 17 after the toner image is transferred.

  Each of the developing devices 10Y, 10M, 10C, and 10K includes a housing 20, in which a two-component developer having a magnetic carrier and toner is stored. In the housing 20, two agitation rollers 11 and 12 (developer agitation members) are rotatably arranged in parallel near the bottom of the housing with the longitudinal direction as an axial direction.

  A developer circulation path is set on the inner bottom surface of the housing 20, and the stirring rollers 11 and 12 are disposed in the circulation path. In the axial direction between the stirring rollers 11 and 12, a partition wall 201 erected from the bottom of the housing is provided. The partition wall 201 divides the circulation path, and the circulation path is formed so as to go around the partition wall 201. The two-component developer is charged while being stirred and conveyed by the stirring rollers 11 and 12 through this circulation path.

  The two-component developer circulates in the housing 20 while being stirred by the stirring rollers 11 and 12, the toner is charged, and the two-component developer on the stirring roller 11 is attracted to the magnetic roller 14 located on the upper side. Are transported. The sucked two-component developer forms a magnetic brush (not shown) on the magnetic roller 14, the layer thickness of which is regulated by the doctor blade 13, and the potential difference between the magnetic roller 14 and the developing roller 15 A toner layer is formed on the developing roller 15. Then, the electrostatic latent image on the photosensitive drum 17 is developed by the toner layer on the developing roller 15.

  The exposure unit 94 includes various optical system devices such as a light source, a polygon mirror, a reflection mirror, and a deflection mirror, and is based on image data on the peripheral surface of the photosensitive drum 17 provided in each of the image forming units 93. Irradiate light to form an electrostatic latent image.

  The intermediate transfer unit 92 includes an intermediate transfer belt 921, a driving roller 922, and a driven roller 923. The intermediate transfer belt 921 primarily transfers toner images from a plurality of photosensitive drums 17 in an overcoated state, and secondarily transfers the toner images to the sheet P supplied from the paper supply unit 130 at the secondary transfer unit 98. . The driving roller 922 and the driven roller 923 drive the intermediate transfer belt 921 to rotate. The driving roller 922 and the driven roller 923 are rotatably supported by a housing (not shown).

  The sheet feeding unit 130 stores a sheet bundle S composed of a plurality of sheets P on which images are formed, and is detachably attached to the housing 90.

  The fixing unit 97 performs a fixing process on the toner image on the sheet P that has been secondarily transferred from the intermediate transfer unit 92. It is discharged toward the discharge unit 96 formed in the above.

  The paper discharge unit 96 discharges the sheet P conveyed from the fixing unit 97 onto a top cover 911 serving as a paper discharge tray.

  The sheet supply unit 100 includes a plurality of stages (three stages in the present embodiment) of paper feed units (paper feeders) 130 that are detachably attached to the printer main body 200. Each stage of the sheet feeding unit 130 stores the sheet bundle S of each size, and the selected sheet feeding unit 130 is driven by a pickup roller 40 provided in the sheet feeding unit 130. The uppermost sheet P of the sheet bundle S is taken out one by one, and is fed out to the paper feed conveyance path 133 by a primary paper feed mechanism and a secondary paper feed mechanism described later, and is introduced into the image forming unit 93. It is like that.

  Each of the paper feeding units 130 includes a transport mechanism that can be stacked and installed in the lower part of the printer main body 200, and a desired number of paper feeding units 130 can be attached to the printer main body 200 at any time. That is, by stacking a plurality of paper feed units 130 below the printer body 200, the transport mechanisms of the paper feed units 130 are coupled to each other to form a single paper feed transport path 133 extending to the printer body 200. Is done. As a result, a plurality of stacked sheet feeding units 130 can be attached later.

  In this embodiment, an example is given in which the sheet supply unit 100 is configured by a three-stage sheet feeding unit 130, but the present invention is not limited to this, and the sheet feeding unit 130 is one-stage or two-stage, or four The present invention can be similarly applied to an image forming apparatus such as a printer configured with a sheet feeding unit of more than one stage.

  Next, with reference to FIGS. 1, 3 to 5, the configuration of each sheet feeding unit (sheet feeding device) 130 installed in the sheet feeding unit 100 of the color printer 1 according to the present embodiment will be described in detail. .

  FIG. 3 is a cross-sectional view illustrating a configuration of the paper feeding device according to the present embodiment. FIG. 4 is a perspective view showing a state in which the paper feeding cassette in the paper feeding device shown in FIG. 3 is pulled out from the paper feeding device body. FIG. 5 is an explanatory diagram illustrating a position detection sensor mounted on the sheet feeding device illustrated in FIG. 3.

  As shown in FIGS. 3 and 4, the sheet feeding unit 130 has a lift plate (sheet stacking plate) for stacking a sheet bundle S composed of a plurality of sheets (sheet-like recording media) P on the inner bottom surface of the sheet storage unit 35. ) 31. The lift plate 31 is rotatably supported at its upstream end (left end portion in FIG. 3) in the sheet feeding direction by a support portion 38. That is, the lift plate 31 is rotatable in the vertical plane by the support portion 38 with the downstream end as a free end inside the sheet storage portion 35. The support portions 38 are provided on both side walls of the sheet storage portion 35 that are arranged to face each other in the width direction of the sheet P (a direction orthogonal to the sheet feeding direction).

  A sheet feeding cassette 130A of the sheet feeding unit 130 includes a width alignment cursor pair 34a and 34b for positioning the sheet P stored in the sheet storage unit 35 in the width direction, a rear end cursor 33 for aligning the rear end of the sheet P, It has. The width alignment cursor pairs 34a and 34b are provided so as to be able to reciprocate in the sheet width direction (arrow AA ′ direction in FIG. 4) along guide rails (not shown). Here, since the sheet P is sent out in the direction of arrow B, the rear end cursor 33 is provided so as to be capable of reciprocating along the guide rails 33a and 33b in parallel with the sheet conveying direction (in the direction of arrow BB 'in FIG. 4). The sheet bundle S is stored in a predetermined position in the sheet feeding unit 130 by moving the width alignment cursor pair 34a and 34b and the rear end cursor 33 in accordance with the size of the stacked sheets. The sheet feeding unit 130 includes a cassette cover 43, and the surface side (side seen from the direction of arrow C in FIG. 4) is exposed to the outside and constitutes a part of the exterior surface of the color printer 1.

  A drive shaft 36, a push-up member 32, and a drive connecting member (not shown) are provided below the lift plate 31 on the downstream side in the sheet feeding direction as a lift mechanism that lifts and lowers the lift plate 31. The sheet feeding unit main body 130B is provided with a receiving member (not shown) corresponding to the drive connecting member and a forward / reversely movable lift motor (not shown) connected to the receiving member. In a state where the paper feed cassette 130A is housed in the paper feed unit main body 130B, the drive connecting member of the sheet storage unit 35 on the paper feed cassette 130A side is engaged with and connected to the receiving member on the paper feed unit main body 130B side. Thereby, the power of the lift motor can be transmitted to the drive shaft 36. The drive shaft 36, the push-up member 32, the drive connecting member, the receiving member, and the lift motor constitute an elevating mechanism 30 that displaces the lift plate 31 between the paper feed position and the separation position.

  In the present embodiment, the paper feeding position is a position where the lift plate 31 is lifted and the upper surface of the sheet bundle S placed on the lift plate 31 comes into contact with the pickup roller 40 and can feed paper. The separation position is a position where the upper surface of the sheet bundle S is separated from the pickup roller 40, and has a minimum necessary distance to avoid contact between the upper surface of the selected type of sheet P and the pickup roller 40. This is the position where the lift plate 31 is lowered to the position.

  The type of sheet P to be fed can be selected by the sheet setting unit 39. The sheet setting unit 39 can be provided on an operation panel (not shown) of the paper feeding unit 130 or the printer main body 200.

  In addition, as a lift motor which comprises the raising / lowering mechanism which raises / lowers the lift board 31, a stepping motor, a DC motor, etc. can be used, for example.

  Further, as shown in FIG. 3, the paper feed unit 130 includes, as a primary paper feed mechanism, a primary paper feed roller 41 provided on the downstream side in the transport direction of the pickup roller 40 and a lower side of the primary paper feed roller 41. And a whirling roller 42. Further, a secondary paper feed roller pair 44 and 45 is provided as a secondary paper feed mechanism on the downstream side in the transport direction of the primary paper feed mechanism. The primary paper feed roller 41 is provided along with the pickup roller 40 on the paper feed unit main body 130B side, while the separating roller 42 and the secondary paper feed roller 45 are provided on the paper feed cassette 130A side. When the paper feed cassette 130A is attached to the paper feed unit main body 130B, the primary paper feed roller 41 and the separating roller 42 come into contact with each other.

  The primary paper feed roller 41 feeds the sheet P taken out by the pickup roller 40 to the secondary paper feed roller 44. The primary paper feed roller 41 rotates in a direction in which the sheet P can be conveyed downstream, whereas the separating roller 42 rotates in a direction in which the sheet P is sent back upstream. Even if the sheets P picked up by the pickup roller 40 are overlapped, the separation roller 42 can prevent sheets other than the uppermost sheet P from being fed in the direction of the secondary sheet feed roller 44. Only the upper layer sheet P is conveyed by the primary sheet feed roller 41 to the secondary sheet feed roller 44. The secondary paper feed roller 44 transports the sheet P to the paper feed transport path 133 (see FIG. 2).

  Further, as shown in FIGS. 5A and 5B, the sheet feeding unit 130 detects that the uppermost sheet P of the sheet bundle S placed on the lift plate 31 is at the sheet feeding position. A position detection sensor PS is provided. The position detection sensor PS includes a light shielding member PSA and an optical sensor PSB. The optical sensor PSB includes a light emitting element fixedly provided near the pickup roller 40 and a light receiving element that receives light emitted from the light emitting element. On the other hand, the light shielding member PSA is provided on the support member 50 of the pickup roller 40. Further, the support member 50 is provided so as to be rotatable about the rotation axis of the paper feed roller 41. As a result, when the upper surface of the sheet bundle S placed on the lift plate 31 moves to the sheet feeding position shown in FIG. 5B by the lift of the lift plate 31, the pickup roller 40 pushes up to the uppermost sheet P. It rotates about the rotation axis of the primary paper feed roller 41 and is displaced slightly upward. At this time, the light shielding member PSA is lifted upward in conjunction with the pickup roller 40 to shield the optical path of the optical sensor PSB and to detect that the upper surface of the sheet bundle S is at the paper feeding position.

  In the sheet feeding unit 130 configured as described above, the push-up member 32 pushes up the downstream end side of the lift plate 31 while engaging the bottom surface of the lift plate 31 by the operation of the lift motor. As a result, the upper surface of the sheet bundle S stacked on the lift plate 31 is displaced to the paper feed position where it abuts on the pickup roller 40 provided above the paper feed cassette 130A.

  At this time, as shown in FIG. 5B, when the position detection sensor PS detects the displacement of the pickup roller 40 to the paper feed position, the drive of the lift motor is stopped.

  With reference to FIGS. 6 to 9, the sheet conveying operation according to the present embodiment will be described in detail below.

  FIG. 6 is an explanatory diagram illustrating a schematic configuration of the sheet conveying mechanism according to the present embodiment. FIG. 7 is a plan view of the primary sheet feeding mechanism according to the present embodiment as viewed from above. FIG. 8 is an explanatory diagram for explaining a one-way mechanism provided on the rotation shaft of the pickup roller. 9 is a cross-sectional view (a cross-sectional view taken along the line Y-Y) at the position indicated by the alternate long and short dash line Y in FIG.

  The sheet feeding unit 130 according to this embodiment includes a sheet conveying mechanism illustrated in FIG. The sheet conveying mechanism abuts on the upper surface of the sheet bundle S placed on the lift plate 31 and is provided on the downstream side of the pickup roller 40 in the sheet conveying direction with the pickup roller 40 sending out the uppermost sheet P of the sheet bundle S. A primary sheet feeding mechanism that conveys the sheet P sent out by the pickup roller 40 to the downstream side in the sheet conveying direction, and a primary sheet feeding mechanism that is provided on the downstream side in the sheet conveying direction of the primary sheet feeding mechanism. A secondary paper feeding mechanism is further provided that feeds the conveyed sheet P to the downstream image forming unit 93. The primary paper feed mechanism is composed of a primary paper feed roller 41 and a separating roller 42. The secondary paper feed mechanism is composed of a pair of secondary paper feed rollers 44 and 45. The pickup roller 40 is linked to the drive motor M via the clutch CL0. The primary paper feed roller 41 is connected to the drive motor M via the clutch CL1. The secondary paper feed roller 44 is linked to the drive motor M via the clutch CL2.

  As shown in FIG. 6, the sheet conveying mechanism receives signals from the conveying switch SW1 and the main body switch (passing point switch) SW2, and the control unit 300 causes the driving motor M, the pickup roller 40, and the primary sheet feeding roller to be received. 41 and the secondary paper feed roller 44 are connected to each other via clutches CL0 to CL2. The control of the sheet conveying mechanism by the control unit 300 will be described in detail later.

  Next, the configuration of the pickup roller drive mechanism and the primary paper feed roller drive mechanism will be described with reference to FIGS.

  As shown in FIG. 7, the pickup roller 40 is formed by integrally forming a rotary shaft 40a and a roller body 40b through which the rotary shaft 40a passes. Further, the primary paper feed roller 41 is formed by integrally forming a rotary shaft 41a and a roller body 41b through which the rotary shaft 41a passes. The pickup roller 40 and the paper feed roller 41 are rotatably supported by a support member (not shown) provided in the printer main body 200 by the rotation shafts 40a and 41a.

  Similarly, the roller 42 is formed by integrally forming a rotating shaft 42a and a roller body 42b through which the rotating shaft 42a passes. The roller 42 is rotatably supported by the paper feed cassette 130A by a rotating shaft 42a, and is pressed against the paper feed roller 41 by an urging means (not shown). Further, a torque limiter is provided on the rotating shaft 42a of the separating roller 42, and is configured to be driven to rotate by the primary sheet feeding roller 41 only when a predetermined rotational force is applied.

  The rotation shaft 41 a of the primary paper feed roller 41 is connected to a drive motor M that is a drive source by a drive shaft 65, and is rotated by the drive motor M. Further, a one-way clutch 66 (first clutch CL1 in FIG. 6) is provided at the connecting portion between the rotary shaft 41a and the drive shaft 65, and even when the drive motor M is stopped and the drive shaft 65 does not rotate, the primary The paper feed roller 41 can be rotated in the sheet conveying direction.

  Further, a branch gear 67 is attached to the drive shaft 65, and is connected to a gear 69 that is rotatably attached to the rotation shaft 40 a of the pickup roller 40 via a relay gear 68. Further, the gear 69 is connected to the roller body 40b via the coupling 70 (the 0th clutch CL0 in FIG. 6), and thereby the drive from the drive motor M is branched to the pickup roller 40. The branch gear 67 and the gear 69 are designed so that the rotation speeds of the pickup roller 40 and the primary paper feed roller 41 are the same.

  Here, with reference to FIG. 8, the gear 69 and the coupling 70 attached to the rotating shaft 40a of the pickup roller 40 will be described in detail. As shown in FIG. 8A, the gear 69 and the coupling 70 have a rotation shaft 40a passing through the center thereof, and are rotatably attached to the rotation shaft 40a. Further, the coupling 70 is slidable between the roller body 40b and the gear 69 in the axial direction of the rotary shaft 40a.

  And the protrusions 69a and 70a are integrally formed in the mutually opposing surface of the gear 69 and the coupling 70, respectively. The driving force from the driving motor M is transmitted to the pickup roller 40 by the contact of these protrusions 69a and 70a. These protrusions 69a and 70a are provided with a predetermined play in the rotation direction. The protrusion 69a is formed with an inclined surface 69b. When a driving force is transmitted from the gear 69 to the coupling 70, as shown in FIG. 8B, the protrusion 70a extends along the inclined surface 69b. The coupling 70 is slid toward the roller body 40b.

  Further, face gears 70b and 40c configured so as to be able to transmit driving only in one direction are integrally formed on the surfaces of the coupling 70 and the roller body 40b facing each other, and the coupling 70 is formed as described above. When the roller body 40b is slid toward the roller body 40b, the face gears 70b and 40c are engaged with each other, and the drive transmitted from the gear 69 to the coupling 70 is transmitted to the roller body 40b. Is rotated in the sheet conveying direction.

  Here, when the pickup motor 40 is rotated in the sheet conveying direction when the drive motor M is stopped and the gear 69 is not rotated, the coupling 70 meshing with the roller body 40b is also rotated in the same direction. However, when the play 69a / 70a is rotated by the amount of play provided, the protrusions 69a / 70a come into contact from the opposite side as shown in FIG. 8C. Since the gear 69 cannot rotate, the coupling 70 cannot rotate any more, and the roller body 40b cannot rotate any more.

  However, since the coupling 70 is slidable in the axial direction of the rotation shaft 49a, the coupling 70 is slid toward the gear 69 by the inclination of the face gears 70b and 40c as shown in FIG. The As a result, the meshing of the face gears 70b and 40c is released, and the roller body 40b can be rotated in the sheet conveying direction. That is, the pickup roller 40 has a one-way mechanism by the gear 69 and the coupling 70.

  As shown in FIG. 9A, the pickup roller 40 and the primary paper feed roller 41 are driven to rotate in the sheet conveying direction by driving from the drive motor M. At this time, the separating roller 42 is in direct contact with the primary sheet feeding roller 41, and the frictional force at the contact portion is strong, and a rotational force greater than a predetermined value is applied to the separating roller 42. For this reason, the torque limiter operates and the roller 42 is driven to rotate by the paper feed roller 41. Accordingly, the sheet P sent out by the pickup roller 40 smoothly enters the nip portion between the primary paper feed roller 41 and the separating roller 42.

  In addition, when a plurality of sheets P are simultaneously fed to the nip portion by the pickup roller 40, the frictional force between the sheets P is small, and a predetermined rotational force or more is applied from the primary paper feed roller 41 to the separation roller 42. Since the torque limiter is not applied, the winding roller 42 does not rotate following the primary paper feed roller 41. As a result, only the uppermost sheet P that is in contact with the primary paper feed roller 41 is transported to the downstream side.

  The conveyed sheet P is conveyed to a pair of secondary paper feed rollers 44 and 45 provided downstream in the sheet conveyance direction. The secondary paper feed roller pair 44/45 is provided with a transport switch SW1 for detecting the transport of the sheet P. When the leading edge of the transported sheet P is sandwiched between the transport roller pair 44/45, the driving is performed. The driving of the motor M is configured to be temporarily stopped.

  Thereafter, when the sheet P is transported by the pair of secondary paper feed rollers 44 and 45, the pickup roller 40 and the primary paper feed roller 41 are rotated in the sheet transport direction by the transported sheet P. At this time, as described above, the coupling 70 is reversely rotated until the protrusions 69a and 70a abut from the opposite side, and as shown in FIG. 9C, the coupling 70 is reversed by the play amount provided on the protrusions 69a and 70a. Will be rotated.

  When the pickup roller 40 and the primary paper feed roller 41 are rotationally driven by the drive motor M to convey the next sheet S, the primary paper feed roller 41 starts to rotate immediately. Since the drive is not transmitted until the play of the protrusions 69a and 70a is eliminated due to the influence of the play that has been rotated previously, the pickup roller 40 starts to rotate with a delay from the start of the rotation of the primary paper feed roller 41. .

  In the present embodiment, the waste of power consumption of the drive motor is eliminated by controlling the drive of the primary paper feed mechanism and the secondary paper feed mechanism that convey the sheet to the image forming unit. . Hereinafter, control of the primary sheet feeding mechanism and the secondary sheet feeding mechanism will be described below with reference to FIGS. 6, 10, and 11.

  FIG. 10 is a functional block diagram of a control unit that controls driving of the paper feed mechanism according to an embodiment of the present invention. FIG. 11 is a flowchart showing a control process by the control unit shown in FIG.

  As shown in the functional block diagram of FIG. 10, the paper feeding unit 130 according to the present embodiment includes a control unit 300 that controls the operation of the roller driving mechanism 30 based on detection signals from the transport switch SW1 and the main body switch SW2. I have.

  The control unit 300 includes an information input / output unit 85, a roller drive mechanism control unit 80, and a storage unit 84.

  The information input / output unit 85 receives a detection signal from the transport switch SW1 and the main body switch SW2, a time-up signal from the timer 86, a paper feed command signal from the CPU 210 on the printer main body 200 side, and the like.

  The roller drive mechanism control unit 80 includes a delay detection unit 82, and controls the drive of the roller drive mechanism 30 based on each signal input to the information input / output unit 85, and controls the first clutch CL1 and the second clutch CL2. The connection between the drive motor M and the primary paper feed roller 41 and the secondary paper feed roller 44 is switched ON / OFF.

  For example, an operation program of the control unit 300 is stored in the storage unit 84. In addition, the storage unit 84 is provided with a storage area for temporarily storing determination results and other information.

  The control unit 300 can be configured by, for example, a CPU, a memory (such as a ROM and a RAM), an input interface, and an output interface.

  Next, with reference to FIG. 11, the control process by the control part 300 which concerns on this embodiment is demonstrated.

  First, when a paper feed command signal is input from the CPU 210 on the printer body 200 side via the information input / output unit 85 and paper feed is started (S1), the roller drive mechanism control unit 80 A signal for turning on the connection between the 0th clutch CL0 and the first clutch CL1 and the drive motor M and a drive signal for driving the drive motor M are output via the information input / output unit 85. Thereby, driving of the pickup roller 40 and the primary paper feed roller 41 is started (S2).

  When it is detected by the transport switch SW1 that the leading edge of the sheet P fed out by the pickup roller 40 and transported by the primary paper feed roller 41 has reached the secondary paper feed roller 44 (YES in S3). The pickup roller 40 and the primary paper feed roller 41 and the secondary paper feed roller pair 44/45 are temporarily stopped and the leading edge of the sheet P is sandwiched between the secondary paper feed roller pair 44/45. (S4). At the same time, the timer 86 starts measuring a predetermined delay judgment time (S5). Further, the roller drive mechanism control unit 80 outputs a signal for turning on the connection between the second clutch CL <b> 1 and the drive motor M to the roller drive mechanism 30 via the information input / output unit 85. Thereby, the driving of the secondary paper feed roller 44 is started (S6).

  If the main body switch SW2 detects the leading edge of the sheet P before the timer 86 finishes measuring the predetermined delay determination time (YES in S7), the sheet P conveyance time is not delayed. Even when the sheet P is conveyed to the image forming unit 93, the normal driving mode in which the driving of the primary paper feeding roller 41 is stopped during the paper feeding by the driving of the secondary paper feeding roller 44 is set (S9). On the other hand, if the leading edge of the sheet P is not detected by the main body switch SW2 even after the timer 86 completes the predetermined delay determination time, a delay in the conveyance time of the sheet P is detected (YES in S8). When the subsequent sheet P is conveyed to the image forming unit 93, the driving mode at the time of delay is set to drive the primary paper feed roller 41 even during paper feed by driving the secondary paper feed roller 44 (S10).

  Even when a coated paper or the like that is likely to cause a roller slip problem is selected as in the present embodiment, the normal driving mode is used while the conveyance time of the sheet P is not delayed. The effect of reducing power consumption is increased.

  Further, when a delay in the conveyance time of the sheet P is detected and the subsequent sheet P is conveyed to the image forming unit 93, the primary paper supply roller 41 is moved even during the paper supply by driving the secondary paper supply roller 44. Even when the driving mode at the time of delay is applied, it is desirable to switch to the normal driving mode if the following conditions are satisfied.

  That is, the control unit 300 is configured to switch to the normal driving mode when the delay detection unit 82 does not detect a delay in the transport time continuously during the control of the delay driving mode. It is desirable to do.

  As described above, the sheet feeding unit 130 according to this embodiment includes the primary sheet feeding roller 41 that conveys the sheet P sent out from the lift plate 31 along the predetermined conveyance path, and the primary sheet feeding roller 41. The sheet P, which is provided downstream of the sheet conveyance direction and conveyed by the primary sheet feeding roller 41, is conveyed by the secondary sheet feeding roller 44 and the secondary sheet feeding roller 44 that conveys the sheet P to the image forming unit 93. A delay detection unit 82 that detects a delay in conveyance time until the leading edge of the sheet P reaches a predetermined passing point in the conveyance path between the secondary paper feed roller 44 and the image forming unit 93; and a delay detection unit 82 Until the delay of the conveyance time is detected by the normal time driving during which the primary paper feeding roller 41 is stopped during the paper feeding by the driving of the secondary paper feeding roller 44, the conveyance time is detected by the delay detection unit 82. Delay After the detection, the primary paper feed roller 41 and the secondary paper feed roller 44 are driven so that the primary paper feed roller 41 is driven during delay so that the primary paper feed roller 41 is driven even during the paper feed by the drive of the secondary paper feed roller 44. And a control unit 300 that controls driving.

  According to the above configuration, when the sheet P is performed without delay, during the paper feeding by the driving of the secondary paper feeding roller 44, the normal driving for stopping the driving of the primary paper feeding roller 41 is performed, When a delay in transport time until reaching a predetermined passing point in the transport path between the secondary paper feed roller 44 and the image forming unit 93 is detected, even during paper feed by driving the secondary paper feed roller 44 Control is performed so as to drive at the time of delay for driving the primary paper feed roller 41. For this reason, it is possible to appropriately switch between the normal time driving and the delay time driving in accordance with the state of conveyance of the sheet P to the image forming unit 93. Thereby, for example, even when a sheet with high surface smoothness such as coated paper is used, the problem of delay in sheet conveyance due to roller slip is avoided without causing unnecessary increase in power consumption. It is possible to realize a paper feeding device that can realize good sheet conveyance to the forming unit 93.

  In the above configuration, the image forming apparatus further includes a conveyance switch SW1 that detects that the leading edge of the sheet P has reached the secondary paper feed roller 44, and the control unit 300 detects when the leading edge of the sheet P is detected by the conveyance switch SW1. When the primary paper feeding roller 41 is stopped and the secondary paper feeding roller 44 is temporarily stopped with the leading edge of the sheet P being sandwiched, the secondary paper feeding roller 44 is driven when the normal driving is performed. In the case where the sheet P is conveyed to the image forming unit 93 by the above-described operation and the driving at the time of delay is performed, the sheet P is conveyed to the image forming unit 93 by driving the primary sheet feeding roller 41 and the secondary sheet feeding roller 44. A configuration may be adopted.

  According to the above configuration, switching between the normal driving and the delay driving is performed at the timing when the conveyance switch SW1 that detects that the leading edge of the sheet P has reached the secondary paper feed roller 44 is turned on. be able to.

  In the above configuration, the delay detection unit 82 further includes a main body switch SW2 that is provided at the passing point and detects that the leading end of the sheet P has reached the passing point, and the delay detecting unit 82 detects the leading end of the sheet P by the transport switch SW1. A timer 86 for measuring a predetermined delay determination time after the start, and even if the timer 86 completes the predetermined delay determination time, the sheet switch P2 does not detect the leading edge of the sheet P. It is desirable to adopt a configuration that detects a delay in the conveyance time of P.

  According to the above configuration, the main body switch SW2 that detects that the leading edge of the sheet P has reached the predetermined passing point in the conveyance path between the secondary paper feeding roller 44 and the image forming unit 93, and the leading edge of the sheet P. The delay detection unit 82 uses a timer 86 that measures a predetermined delay determination time after the transport switch SW1 detects it, so that the front end of the sheet P can be detected even if the timer 86 completes the measurement of the predetermined delay determination time. Is not detected by the main body switch SW2, it is possible to detect a delay in the conveyance time of the sheet P and switch to the driving at the time of delay.

  In the above-described configuration, when the delay time drive control is continued, when the delay detection unit 82 does not detect a delay in the conveyance time continuously, the normal time drive may be controlled thereafter. desirable.

  According to the above configuration, when the delay of the conveyance time is detected by the delay detection unit 82 and the delay in the conveyance time is not detected continuously for a predetermined number of sheets thereafter even after switching to the driving at the time of delay. The drive is switched to normal driving again. As a result, after switching to driving at the time of delay, waste of power consumption can be reduced compared to a configuration in which driving at the time of delay is continued regardless of whether or not the subsequent conveyance is performed without delay. Can do.

  The sheet feeding device of the present invention can be applied to all image forming apparatuses such as a printer, a copier, a facsimile, or a complex machine having a combination of these functions, and is particularly glossy art paper. In addition, it can be suitably used when a sheet having high surface smoothness such as coated paper is used.

1 is a perspective view illustrating an appearance of a printer including a paper feeding device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an internal configuration of the printer illustrated in FIG. 1. It is sectional drawing which shows the structure of the paper feeding apparatus which concerns on one Embodiment of this invention. FIG. 4 is a perspective view illustrating a state in which a sheet feeding cassette in the sheet feeding device illustrated in FIG. 3 is pulled out from a sheet feeding device body. It is explanatory drawing which shows the position detection sensor mounted in the paper feeder shown in FIG. It is explanatory drawing which shows schematic structure of the sheet | seat conveyance mechanism which concerns on one Embodiment of this invention. It is explanatory drawing which shows schematic structure of the sheet | seat conveyance mechanism which concerns on one Embodiment of this invention. It is explanatory drawing which shows schematic structure of the sheet | seat conveyance mechanism which concerns on one Embodiment of this invention. It is explanatory drawing which shows schematic structure of the sheet | seat conveyance mechanism which concerns on one Embodiment of this invention. FIG. 4 is a functional block diagram of a control unit that controls driving of a paper feed mechanism according to an embodiment of the present invention. It is a flowchart which shows the control process by the control part which concerns on one Embodiment of this invention.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 1 ... Color printer (image forming apparatus), 30 ... Roller drive mechanism, 31 ... Lift plate (sheet stacking plate), 39 ... Sheet setting part, 40 ... Pickup roller, 41 ... Primary feed roller , 42... Rolling roller, 44... Secondary feeding roller, 45... Secondary feeding roller, 80... Roller drive mechanism control unit, 82 ... Delay detection unit, 84. Information input / output unit, 86 ... timer, 93 ... image forming unit (image forming unit), 100 ... sheet supply unit, 130 ... paper feeding unit (paper feeding device), 130A ... paper feeding cassette, 130B ... ... Paper feeding unit main body 200 ... Printer main body 300 ... Control unit CL1 ... First clutch, CL2 ... Second clutch, P ... Sheet, S ... Sheet bundle, SW1 ... Conveyance switch, SW2 ...... Main unit switch ( Over point switch), the sheet bundle, PS ...... position sensor, M ...... drive motor

Claims (5)

A paper feeding device used in an image forming apparatus provided with an image forming unit,
A primary sheet feeding mechanism for conveying a sheet-like recording medium fed from the sheet storage unit along a predetermined conveyance path;
A secondary paper feed mechanism that is provided on the downstream side of the primary paper feed mechanism in the sheet transport direction and transports the sheet-like recording medium transported by the primary paper feed mechanism to the image forming unit;
A transport time delay until the leading edge of the sheet-like recording medium transported by the secondary paper feed mechanism reaches a predetermined passing point in the transport path between the secondary paper feed mechanism and the image forming unit is reduced. A delay detector to detect;
Until the delay detection unit detects a delay in transport time, during the paper feeding by the driving of the secondary paper feeding mechanism, the driving of the primary paper feeding mechanism is stopped and the normal driving is stopped, while the delay sensing After the conveyance time delay is detected by the unit, the primary paper feed mechanism and the primary paper feed mechanism are driven so that the primary paper feed mechanism is driven even during paper feed by the drive of the secondary paper feed mechanism. And a control unit that controls driving of the secondary sheet feeding mechanism. A transport switch for detecting that the leading edge of the sheet-like recording medium has reached the secondary paper feed mechanism;
The controller is
When the leading edge of the sheet-like recording medium is detected by the transport switch, the primary paper feeding mechanism is stopped, and the secondary paper feeding mechanism is also temporarily stopped while the leading edge of the sheet-like recording medium is sandwiched. After
When performing the normal driving, the sheet-like recording medium is conveyed to the image forming unit by driving the secondary paper feeding mechanism,
2. The sheet feeding device according to claim 1, wherein when performing the delay driving, the sheet-like recording medium is conveyed to the image forming unit by driving the primary sheet feeding mechanism and the secondary sheet feeding mechanism. Paper device. A passing point switch that is provided at the passing point and detects that the leading edge of the sheet-like recording medium has reached the passing point;
The delay detection unit
A timer for measuring a predetermined delay judgment time after the leading edge of the sheet-like recording medium is detected by the transport switch;
If the leading edge of the sheet-like recording medium is not detected by the passing point switch even after the timer completes the predetermined delay judgment time, the delay of the conveyance time of the sheet-like recording medium is detected. The sheet feeding device according to claim 2.   The control unit performs control so as to perform the normal driving thereafter when the delay detection unit does not detect the delay of the conveyance time continuously while the control of the driving at the delay is continued. The sheet feeding device according to any one of claims 1 to 3. A paper feeding device according to any one of claims 1 to 4,
An image forming apparatus comprising: an image forming apparatus main body that forms an image on a sheet-like recording medium fed from the paper feeding apparatus.

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