JP2018002368A - Medium supply device - Google Patents

Abstract

Provided is a medium supply device in which double feeding is unlikely to occur. A medium supply device includes a plurality of conveyor rollers (1a to 1e) that are arranged in a medium transport direction (+ y direction) and that sequentially transport media (13) stacked at a medium stacking position from below, and a motor ( 101) and a plurality of conveyor rollers (1a to 1e) using a driving force generated by the motor (101) via a plurality of clutches (107a to 107e) corresponding to the plurality of conveyor rollers (1a to 1e) as a first torque. ) And one or more conveyors as a second torque that is weaker than the first torque through the one or more torque limiters (201b to 201e). And a sub gear train that transmits to the rollers (1b to 1e). [Selection] Figure 11

Description

  The present invention relates to a medium supply device that feeds out and supplies the lowest medium among a plurality of media stacked at a medium stacking position.

  2. Description of the Related Art Conventionally, there has been proposed a medium (sheet) supply device that sequentially feeds and supplies the lowest medium (lowest medium) among a plurality of media stacked (set) at a medium stacking position (on a feed mechanism). (For example, refer to Patent Document 1). This device is used to pass only the lowest-order several of the stacked media when the lowest-order medium is transported by the feed mechanism that contacts the lowest-order medium among the plurality of stacked media. The first separation part including the regulation guide (slope part) provided with a gap (medium path) and several media that have passed through the first separation part are separated by the deterring force (braking force) by the retard roller, and the lowest A second separation unit that conveys only the medium (only one sheet) downstream; and a sheet pressing unit that has a function of preventing medium non-feeding that may occur when the contact pressure between the medium and the feed mechanism decreases. ing.

JP 2001-97563 A

  In the above-described conventional medium supply apparatus, when the lowest-order medium in contact with the feed mechanism advances, the rear end side of the second medium from the lowest position comes into contact with the feed mechanism and a strong feed force (first force in the medium conveyance direction). ) Is added to the second medium from the bottom. Furthermore, due to the friction between the lowest medium and the second medium from the lowest generated due to the weight of the loaded medium, the second medium from the lowest has the medium in the medium transport direction drawn by the lowest medium. A force (second force) is also added. For this reason, the total value of the first force and the second force exceeds the deterring force of the retard roller, and passes through the second separation unit while the lowest medium and the second medium from the lowest overlap. There is a problem that a state, that is, double feeding is likely to occur.

  SUMMARY An advantage of some aspects of the invention is that it provides a medium supply device in which double feeding hardly occurs.

  A medium supply device according to an aspect of the present invention includes a plurality of conveyor rollers that are arranged in the medium conveyance direction and sequentially convey the medium stacked at the medium stacking position, and a driving force generation unit that generates a driving force. A main gear train that transmits a driving force generated by the driving force generation unit as a first torque to each of the plurality of conveyor rollers via a plurality of clutches corresponding to the plurality of conveyor rollers; and the driving force generation unit. A sub-gear train that transmits the generated driving force to one or more of the plurality of conveyor rollers as a second torque that is weaker than the first torque via one or more torque limiters. And a roller driving gear train.

  According to the present invention, the driving force generated by the driving force generator is transmitted as the first torque to the conveyor roller on the downstream side in the medium transport direction via the clutch of the main gear train, and in parallel with this, the driving force generator Is transmitted to a plurality of conveyor rollers (including conveyor rollers other than the downstream conveyor roller) as a second torque weaker than the first torque via the torque limiter of the sub gear train. The occurrence of feeding can be prevented, and the occurrence of medium non-feeding can be prevented.

It is a schematic side view which shows the medium supply apparatus of a comparative example. (A) is a schematic side view which shows the conveyor roller drive gear train in the feed mechanism of the medium supply apparatus of a comparative example, (b) is the schematic which looks at the figure (a) in the S2-S2 line direction. . It is a schematic side view which shows the state (before conveyance) of the medium (when medium length is long) and the conveyor roller in the medium supply apparatus of a comparative example. Schematic side view showing the state of the medium (when the medium length is long) and the conveyor roller (when the leading edge of the lowest-order medium passes through the second separation unit and reaches the first medium position sensor) in the medium supply device of the comparative example FIG. Schematic side view showing the state of the medium (when the medium length is long) and the conveyor roller (when the leading edge of the lowest-order medium passes through the feed roller pair and reaches the second medium position sensor) in the medium supply device of the comparative example It is. It is a schematic side view which shows the state of the medium (when medium length is short) and the conveyor roller in the medium supply apparatus of a comparative example. It is a schematic side view which shows the state of the medium (when there is little medium load amount) and the conveyor roller in the medium supply apparatus of a comparative example. It is a schematic side view which shows the medium supply apparatus which concerns on embodiment of this invention. (A) is a schematic side view which shows the conveyor roller drive gear train in the feed mechanism of the medium supply apparatus which concerns on embodiment, (b) is the schematic which looks at the same figure (a) in the S91-S91 line direction (C) is a schematic view of FIG. 10 (a) viewed in the direction of line S92-S92, and (d) is a schematic view of FIG. 10 (a) viewed in the direction of line S93-S93. (e) is the schematic which looks at the figure (a) in the S94-S94 line direction, (f) is the schematic which looks at the figure (a) in the S95-S95 line direction. It is a block diagram which shows roughly the structure of the control system of the medium supply apparatus which concerns on embodiment. It is a schematic side view showing the state of a medium (when the medium length is short and the medium stacking amount is small) and the conveyor roller in the medium supply device according to the embodiment. It is the schematic which shows the state of the conveyor roller (when driving force is transmitted by the main gear train and the sub gear train) in FIG. It is the schematic which shows the state of the conveyor roller in FIG. 11 (when driving force is transmitted by the sub gear train). It is a schematic side view showing the state of a medium (when the medium length is short and the medium stacking amount is large) and a conveyor roller in the medium supply device according to the embodiment.

  First, a medium supply apparatus according to a comparative example will be described with reference to FIGS. 1 to 7, and then a medium supply apparatus (paper feeding apparatus) according to an embodiment of the present invention will be described with reference to FIGS. To do. In order to facilitate understanding of the relationship between the drawings, the drawings show coordinate axes of an xyz orthogonal coordinate system. The x axis is a coordinate axis indicating the width direction of the medium (paper) loaded on the medium supply device. The y-axis is a coordinate axis indicating the medium transport direction (that is, the medium length direction) in the medium supply device. The z-axis is a coordinate axis indicating the height direction of the medium supply device. In the medium supply device of the comparative example, the driving force of the motor is transmitted to the conveyor roller via the clutch gear in the connected state (ON state) (FIG. 2B). On the other hand, in the medium supply device according to the embodiment, the driving force of the motor is one (a sub gear train in FIG. 13) or both (the main gear train in FIG. 12) of a plurality of gear trains having different torque values to be transmitted. It is transmitted to the conveyor roller via the sub gear train.

<< 1 >> Comparative Example FIG. 1 is a schematic side view showing a medium supply device of a comparative example. The medium supply device of the comparative example is in contact with the feed mechanism (conveyor roller mechanism) 100 including the conveyor rollers 1 (1a, 1b, 1c, 1d, and 1e) disposed at the medium stacking position, and the first separation unit 10. A second separation unit (retard mechanism) 20 having a feed roller 21 and a retard roller 22, a feed roller pair 30 having rollers 31 and 32 in contact with each other, a first medium position sensor 41 for detecting the position of the medium, and a first medium position sensor 41. And a two-medium position sensor 42. The first separation unit 10 has a medium passage (gap) 11a having a height (height in the thickness direction of the medium) that allows several sheets (for example, two to three sheets depending on the thickness of one medium) to pass therethrough. The regulation guide (slope part) 11 provided with is provided. The second separation unit 20 allows the lowest medium (lowest medium) among several media that have passed through the medium passage 11a of the first separation unit 10 to pass therethrough. The feed roller pair 30 transports the medium that has passed through the second separation unit 20 in the medium transport direction (+ y direction). The conveyor rollers 1a to 1e (or any one of the conveyor rollers 1a to 1e) are in contact with the lowest medium among the plurality of stacked media, and the lowest medium is in the medium transport direction (+ y direction). Give feed force. By the conveyor rollers 1a to 1e of the feed mechanism 100, the lowest several of the stacked media are moved in the medium transport direction. An appropriate number of the conveyor rollers 1a to 1e is arranged at an appropriate interval according to the length of the usable medium in the y direction (medium length). The number of conveyor rollers 1a to 1e is not limited to the illustrated number.

  FIG. 2A is a schematic side view showing a conveyor roller drive gear train in the feed mechanism 100 of FIG. 1, and FIG. 2B is a schematic view of FIG. 2A viewed in the S2-S2 line direction. is there. The conveyor roller driving gear train of the feed mechanism 100 is a driving force transmission mechanism that transmits the driving force of the motor 101 as a driving force generator to the conveyor rollers 1a to 1e. The conveyor roller drive gear train includes a motor gear 102 attached to the motor shaft of the motor 101, an idle gear 103 (103a to 103e), and an idle gear 104 (104a to 104d). Further, the conveyor roller drive gear train switches the clutch 107 (107a to 107e) to an ON state or an OFF state, thereby switching between transmission and non-transmission of driving force, that is, clutch gears (105a, 105a, 106a), (105b, 106b), (105c, 106c), (105d, 106d), (105e, 106e). Further, the conveyor roller drive gear train includes roller gears 108 (108a to 108e) directly connected to the conveyor rollers 1 (1a to 1e). The clutch state is switched between an ON state in which the clutch gears 105 and 106 are connected and an OFF state in which the clutch gears 105 and 106 are not connected. The clutches 107a to 107e are provided between the clutch gears 105a and 106a, between the clutch gears 105b and 106b, between the clutch gears 105c and 106c, between the clutch gears 105d and 106d, and between the clutch gears 105e and 106e, respectively. Each of the clutches 107a to 107e is switched to an ON state in which the clutch is connected or an OFF state in which the clutch is not connected. The switching of the ON state or OFF state of the clutch is performed by, for example, the control unit of the medium transport device. In addition, the control unit receives the switching between the ON state and the OFF state of the clutch from the detection signals of the first medium position sensor 41 and the second medium position sensor 42, and a higher-level device such as a printer connected to the medium transport device. This can be done based on information about the length.

  For example, the driving force of the motor 101 is transmitted in the order of the motor gear 102, the idle gears 103c, 104b, 103b, 104a, 103a, the clutch gears 105a, 106a (when the clutch 107a is in the ON state), and the roller gear 108a. Rotate.

  The driving force of the motor 101 is transmitted in the order of the motor gear 102, the idle gears 103c, 104b, 103b, the clutch gears 105b, 106b (when the clutch 107b is in the ON state), and the roller gear 108b, thereby rotating the conveyor roller 1b.

  The driving force of the motor 101 is transmitted in the order of the motor gear 102, the idle gear 103c, the clutch gears 105c and 106c (when the clutch 107c is in the ON state), and the roller gear 108c, thereby rotating the conveyor roller 1c.

  The driving force of the motor 101 is transmitted in the order of the motor gear 102, idle gears 103c, 104c, 103d, clutch gears 105d, 106d (when the clutch 107d is in the ON state), and the roller gear 108d to rotate the conveyor roller 1d.

  For example, the driving force of the motor 101 is transmitted in the order of the motor gear 102, the idle gears 103c, 104c, 103d, 104d, 103e, the clutch gears 105e, 106e (when the clutch 107e is in the ON state), and the roller gear 108e. Rotate.

  FIG. 3 is a schematic side view showing a state (before conveyance) of the medium 13 (when the medium length is long) and the conveyor rollers 1a to 1e in the medium supply device of the comparative example. FIG. 4 shows a state of the medium 13 (when the medium length is long) and the conveyor rollers 1a to 1e in the medium supply device of the comparative example (the leading end of the lowest medium 13a passes through the second separation unit 20 and the first medium position). FIG. 6 is a schematic side view showing a state where a sensor 41 is reached. FIG. 5 shows the state of the medium 13 (when the medium length is long) and the conveyor rollers 1a to 1e in the medium supply apparatus of the comparative example (the second medium position sensor with the leading end of the lowest medium 13a passing through the feed roller pair 30). FIG.

  In the medium supply apparatus of the comparative example, the rotation of each of the conveyor rollers 1a to 1e of the feed mechanism 100 is controlled according to the medium length and according to the position of the medium in the y direction. That is, as shown in FIG. 3, when a plurality of media 13 are stacked, when all the conveyor rollers 1a to 1e of the feed mechanism 100 are uniformly rotated in the direction of the arrow, as shown in FIG. While the lowermost medium 13a performs separation and conveyance, the second medium 13b from the lowermost medium must be stopped by the retarding force of the retard roller 8. However, as shown in FIG. 4, since the second lowest medium 13b is in contact with the conveyor roller 1e in the feed mechanism 100, when the conveyor roller 1e is rotated by the driving force of the motor 101, the medium This is because a strong feed force Fe in the + y direction is generated in 13b. At this time, in addition to the feed force Fe, the second medium 13b from the lowest position is attracted to the lowest medium 13a by the inter-sheet friction with the lowest medium 13a generated by the weight of the loaded medium. Since the force Fp is also generated, the force (Fe + Fp) exceeds the deterring force (braking force in the −y direction) of the retard roller 8, and double feed is likely to occur.

  Further, when the conveyance of the lowest medium 13a in the + y direction proceeds, the conveyor rollers 1d, 1c, 1b, and 1a sequentially come into contact with the second medium 13b from the lowest and feed forces Fd, Fc, Fb and Fa are sequentially given to the second medium 13b from the bottom. In this case, the contact area between the lowest medium 13a and the second medium 13b from the lowest is reduced, and the force Fp caused by the inter-sheet friction is reduced, but the + y direction obtained from the conveyor rollers 1d, 1c, 1b, and 1a. Since the feed force is strong, double feed is more likely to occur. If the retard roller 8 generates a deterring force (−y direction) larger than the sum (Fp + Fa + Fb + Fc + Fd + Fe) of the force Fp caused by the inter-sheet friction and the feed force (Fa + Fb + Fc + Fd + Fe) by the conveyor roller, it is possible to prevent double feeding. However, in this case, the strong force (Fp + Fa + Fb + Fc + Fd + Fe) applied to the second lowest medium 13b and the retarding force of the retard roller 8 greatly exceed the strength of the medium itself in a thin medium, and the like. May cause medium damage.

  Therefore, the control unit (not shown) of the medium supply device of the comparative example obtains information on the length of the loaded medium from a host device such as a printer (not shown), and the medium length and the first medium position sensor. 41 and the medium position detection signal from the second medium position sensor 42 are used to control the rotation of the conveyor rollers 1a to 1e. In the example of FIGS. 3 to 5, the conveyor roller 1 e that comes into contact with the second medium 13 b from the lowest position does not rotate from the beginning of the conveyance until the lowest medium 13 a first reaches the first medium position sensor 41. Further, when the lowermost medium 13a is further conveyed, the conveyor rollers 1d, 1c, and 1b in contact with the second medium 13b from the lowermost are sequentially stopped according to the conveyance amount. Further, when the medium reaches the feed roller pair 30 by the medium position detection by the second medium position sensor 42 and a sufficient feed force is obtained, the conveyor rollers 1a to 1e are all stopped. FIG. 5 shows a case where all of the conveyor rollers 1a to 1e are stopped when the lowest-order medium 13a reaches the second medium position sensor 42.

  FIG. 6 is a schematic side view showing a state of the medium 13 (when the medium length is short) and the conveyor rollers 1a to 1e in the medium supply apparatus of the comparative example. The content of control by the control unit of the medium supply device of the comparative example varies depending on the medium length. For example, as shown in FIG. 6, when the medium length is short, only the conveyor rollers 1a and 1b are used as the conveyor rollers at the beginning of medium conveyance. Switching of rotation or stop (following) of the conveyor rollers 1a to 1e is performed by turning on or off the clutch 107 (107a to 107e). When the operation of the conveyor roller is controlled according to the medium length (for example, in the case of FIG. 6), the conveyor roller 1c rotates in the direction in which the feed force is applied with the clutch 107c turned off to prevent double feeding. Absent. Here, the conveyor roller 1c in which the clutch 107c is in the OFF state has a certain (some degree) holding force (a force in a direction that makes it difficult to rotate) due to sliding friction of the drive gear train to the roller shaft and the clutch. However, when the medium loading amount is sufficiently large, the lowest level medium can obtain a strong feed force from the driven conveyor rollers 1a and 1b due to the weight of the loaded medium itself. In order to obtain a force higher than its own holding force from the lowest-order medium 13a, it may rotate together.

  FIG. 7 is a schematic side view showing the state of the medium (when the medium stacking amount is small) 13 and the conveyor rollers 1a to 1e in the medium supply apparatus of the comparative example. As shown in FIG. 7, when the number of media 13 loaded (set) at the beginning is small, or when media is not added and the amount of loaded media is reduced and the remaining number is small, the media weight is reduced. Therefore, the contact pressure between the conveyor rollers 1a to 1c and the medium 13 is reduced. For this reason, the feed forces Fa and Fb obtained by the lowest-order medium 13a from the rotating conveyor rollers 1a and 1b are very small, and the feed force (Fa + Fb) becomes unstable. On the other hand, the lowest-order medium 13a is also in contact with the conveyor roller 1c stopped to prevent double feeding, and receives the braking force Fk due to friction from the stopped conveyor roller 1c. The feed force (Fa + Fb) and the brake force Fk are very small and unstable forces, and Fa + Fb ≦ Fk may occur, and medium non-feeding in which no medium is supplied may occur.

  In the medium supply apparatus according to the embodiments described below, measures are taken to prevent the occurrence of such double feeding and medium non-feeding.

<< 2 >> Embodiment << 2-1 >> Configuration FIG. 8 is a schematic side view showing a medium supply apparatus according to an embodiment of the present invention. 8, components that are the same as or correspond to the components shown in FIG. 1 (comparative example) are assigned the same reference numerals as those shown in FIG. The medium supply apparatus according to the present embodiment is different from the medium supply apparatus shown in FIG. 1 in the structure and operation of the feed mechanism 200.

  FIGS. 9A to 9F are diagrams showing a conveyor roller drive gear train of the feed mechanism 200 of the medium supply device according to the present embodiment. 9 (a) is a schematic side view, FIG. 9 (b) is a schematic view of FIG. 9 (a) in the S91-S91 line direction, and FIG. 9 (c) is the same figure (a). 9 (d) is a schematic view of FIG. 9 (d), FIG. 9 (d) is a schematic view of FIG. 9 (a), and FIG. 9 (e) is a schematic view of FIG. 9 (e). FIG. 9F is a schematic view of FIG. 9A viewed in the direction of the line S95-S95. 9 (a) to 9 (f), the same or corresponding components as those shown in FIGS. 2 (a) and 2 (b) (comparative example) are shown in FIGS. 2 (a) and 2 (b). The same reference numerals are assigned. The conveyor roller drive gear train of the feed mechanism 200 shown in FIGS. 9A to 9F is a main gear train that transmits the first torque to the conveyor rollers 1a to 1e via the clutch 107 (107a to 107e), respectively. A sub gear train that transmits a second torque, which is weaker than the first torque, to one or more of the conveyor rollers 1a to 1e via the torque limiter 201 (201b to 201e) (that is, parallelized) The two different gear trains) are different from the conveyor roller drive gear train of the feed mechanism 100 of the comparative example having only one gear train (corresponding to the main gear train in the present embodiment) via the clutch.

  As shown in FIGS. 9A to 9F, the conveyor roller driving gear train of the feed mechanism 200 transmits a driving force of a motor 101 as a driving force generator to the conveyor rollers 1a to 1e. It is. The conveyor roller driving gear train of the feed mechanism 200 is a main gear train (for example, a thick arrow A in FIG. 12) as a first gear train that transmits a first torque (strong torque) via the clutch 107 (107a to 107e). ) And a sub gear train (for example, FIG. 5) as a second gear train that transmits a second torque (weak torque) weaker than the first torque via the torque limiter 201 (201b to 201e). 13 gear trains arranged along the thin line arrow B).

  The structure and operation of the main gear train in the present embodiment are basically the same as the structure and operation of the conveyor roller drive gear train (FIG. 2A) of the feed mechanism 100 of the comparative example. Therefore, in the description of this embodiment, reference is also made to FIG. The main gear train includes a motor gear 102 attached to the motor shaft of the motor 101, an idle gear 103 (103a to 103e), and an idle gear 104 (104a to 104d). Further, the main gear train includes clutch gears 105 and 106 that perform switching of transmission or non-transmission of driving force by switching the clutch 107 (107a to 107e) to an ON (connected) state or an OFF (non-connected) state. Gears (105a, 106a), (105b, 106b), (105c, 106c), (105d, 106d), (105e, 106e) are provided. Further, the main gear train includes roller gears 108 (108a to 108e) that are directly connected to the conveyor rollers 1 (1a to 1e).

  As shown in FIG. 9B, the coupling (ON state) and the non-coupling (OFF state) between the clutch gears 105a and 106a are switched by the clutch 107a. As shown in FIG. 9C, the coupling (ON state) and the non-coupling (OFF state) between the clutch gears 105b and 106b are switched by the clutch 107b. As shown in FIG. 9D, the coupling (ON state) and the non-coupling (OFF state) between the clutch gears 105c and 106c are switched by the clutch 107c. As shown in FIG. 9 (e), the coupling (ON state) and the non-coupling (OFF state) between the clutch gears 105d and 106d are switched by the clutch 107d. As shown in FIG. 9 (f), the clutch 107 e is switched between connection (ON state) and non-connection (OFF state) between the clutch gears 105 e and 106 e.

  FIG. 10 is a block diagram schematically showing the configuration of the control system of the medium supply device according to the present embodiment. The control unit 40 of the medium transport device performs control of switching the ON state or OFF state of the clutches 107a to 107e and control of driving and stopping of the motor 101. The control unit 40 receives information (for example, information related to the medium length) received from the upper apparatus 50 such as a printer as an image forming apparatus connected to the medium conveying apparatus, for example, when the clutches 107a to 107e are switched on or off. Can be done based on. The control unit 40 can also control the operations of the motor 101 and the clutches 107a to 107e based on detection signals from the first medium position sensor 41 and the second medium position sensor 42.

  As shown in FIGS. 9A to 9D and 2A, the driving force of the motor 101 includes the motor gear 102, idle gears 103c, 104b, 103b, 104a, 103a, clutch gears 105a, 106a (clutch When the roller 107a is in the ON state), the roller gear 108a is transmitted in this order to rotate the conveyor roller 1a with a strong torque (first torque).

  9A, 9C, 9D, and 2A, the driving force of the motor 101 includes the motor gear 102, idle gears 103c, 104b, 103b, and clutch gears 105b, 106b. (When the clutch 107b is in the ON state), it is transmitted in the order of the roller gear 108b to rotate the conveyor roller 1b with a strong torque (first torque).

  Further, as shown in FIGS. 9A and 9D and FIG. 2A, the driving force of the motor 101 is the motor gear 102, the idle gear 103c, the clutch gears 105c and 106c (when the clutch 107c is in the ON state). ), The roller gear 108c is transmitted in this order, and the conveyor roller 1c is rotated with a strong torque (first torque).

  Further, as shown in FIGS. 9A, 9D, 9E, and 2A, the driving force of the motor 101 includes the motor gear 102, idle gears 103c, 104c, 103d, and clutch gears 105d, 106d. (When the clutch 107d is in the ON state), it is transmitted in the order of the roller gear 108d to rotate the conveyor roller 1d with a strong torque (first torque).

  Further, as shown in FIGS. 9A, 9D to 9F, and FIG. 2A, the driving force of the motor 101 includes the motor gear 102, idle gears 103c, 104c, 103d, 104d, 103e, clutch, The gears 105e and 106e (when the clutch 107e is in the ON state) and the roller gear 108e are transmitted in this order to rotate the conveyor roller 1e with a strong torque (first torque).

  Further, as shown in FIGS. 9A to 9F, the conveyor roller drive gear train is a sub-gear train, and the torque limiter 201 (201b to 201d) connected to the idle gear 103c is coaxial with the idle gear 103c. Are idle gears 202c, idle gears 202b, 202d, 202e, idle gears 203 (203b to 203e), and roller gears 204 (204b to 204e).

  9A, 9C, and 9D, the driving force of the motor 101 includes the motor gear 102, idle gears 103c, 104b, and 103b, torque limiter 201b, idle gear 202b, and idle gear 203b. , The roller gear 204b and the roller gear 108b are transmitted in this order to apply a weak torque (second torque), that is, a weak feed force to the conveyor roller 1b.

  Further, as shown in FIGS. 9A and 9D, the driving force of the motor 101 is in the order of the motor gear 102, the idle gear 103c, the torque limiter 201c, the idle gear 202c, the idle gear 203c, the roller gear 204c, and the roller gear 108c. As a result, a weak torque (second torque), that is, a weak feed force is applied to the conveyor roller 1c.

  Further, as shown in FIGS. 9A, 9D, and 9E, the driving force of the motor 101 includes the motor gear 102, the idle gears 103c, 104c, and 103d, the torque limiter 201d, the idle gear 202d, and the idle gear 203b. The roller gear 204d and the roller gear 108d are transmitted in this order to apply a weak torque (second torque), that is, a weak feed force to the conveyor roller 1d.

  As shown in FIGS. 9A, 9D to 9F, the driving force of the motor 101 includes the motor gear 102, the idle gears 103c, 104c, 103d, 104d, 103e, the torque limiter 201e, the idle gear 202e, The gear 203e, the roller gear 204e, and the roller gear 108e are transmitted in this order to apply a weak torque (second torque), that is, a weak feed force to the conveyor roller 1e.

  Therefore, in the main gear train and the sub gear train arranged in parallel, the gear ratio in the gear train from the motor gear 102 to the roller gear 108c and the gear ratio in the gear train from the motor gear 102 to the roller gear 204c are set to be the same. . Further, the conveyor roller 1a must be rotated at the start of the conveyance of the medium regardless of the medium length of the medium (the clutch 107a is in the ON state). The other conveyor rollers 1b, 1c, 1d, and 1e rotate according to the medium length of the medium with the second torque transmitted by the sub gear train, and the strong torque (the first torque transmitted from the main gear train and the sub gear train). 1 torque and second torque).

<< 2-2 >> Operation FIG. 11 shows the medium length of the medium in the medium supply apparatus according to the present embodiment (when the medium length is in the y-direction region occupied by the conveyor rollers 1a to 1c and is short in the y-direction) and the conveyor roller. It is a schematic side view which shows the relationship of 1a-1e. FIG. 12 is a schematic diagram showing the state of the conveyor roller in FIG. 11 (when driving force is transmitted by the main gear train and the sub gear train). FIG. 13 is a schematic diagram showing the state of the conveyor roller (when driving force is transmitted by the sub gear train) in FIG. 11. As shown in FIG. 11, the operation of the gear train that transmits the driving force to the conveyor roller 1 b when the medium is placed on the conveyor rollers 1 a to 1 c is described with reference to FIG. 12. The operation of the gear train that applies driving force to the conveyor roller 1c will be described with reference to FIG.

  As already described with reference to FIGS. 9A to 9F, when the motor 101 is rotating, the driving force of the motor 101 is applied to the conveyor rollers 1a to 1f by the motor gear 102 and the idle gear 103 (103b). ˜103e), and the driving force of the weak torque (second torque) continues to be transmitted via the gear train (sub gear train) via the torque limiters 201b to 201e and the idle gears 202b to 202f.

  Further, in the case shown in FIG. 11, as shown in FIG. 12, the gear train connected to the conveyor roller 1b connects the clutch gears 105b and 106b with the clutch 107b in the ON state, and the arrow A (strong (Ie, the motor gear 102, the idle gear 103c, the idle gear 104b, the idle gear 103b, the clutch gears 105b and 106b shown in FIGS. 9C, 9D, and 2A). The driving force is transmitted by the roller gear 108b), and a sufficiently strong torque (first torque) is transmitted to the conveyor roller 1b.

  Similarly, in the case shown in FIG. 11, the gear train connected to the conveyor roller 1a is a gear train (ie, a gear train that transmits strong torque by connecting the clutch gears 105a and 106a with the clutch 107a turned on. The motor gear 102, the idle gear 103c, the idle gear 104b, the idle gear 103b, the idle gear 104a, the idle gear 103a, the clutch gears 105a and 106a, and the roller gear 108a shown in FIGS. 9B to 9D and FIG. Due to this, the driving force is transmitted, and a sufficiently strong torque (first torque) is transmitted to the conveyor roller 1a.

  On the other hand, as shown in FIG. 13, the gear train connected to the conveyor roller 1c does not connect the clutch gears 105c and 106c with the clutch 107c turned off, so that the driving force along the arrow A is the clutch gear. It is not transmitted from 105c to 106c, but only the driving force along arrow B is transmitted. Here, the value of the torque transmitted by the arrow B is determined by the set value of the torque limiter 201c. This set value is, for example, a state in which medium non-feed occurs, that is, the number of media set on the conveyor roller 1c is very small (for example, about 10), and the lowest level with the conveyor roller 1c. It is a weak torque (second torque) that can rotate the conveyor roller 1c when the contact pressure of the medium 13a is about several grams. This set value may be a weak torque of less than 100 [gf · cm] when converted into an axis per conveyor roller in consideration of, for example, the sliding load of the conveyor roller and the gear train connected thereto. desirable. Accordingly, by setting the setting value of the torque limiter 201 to an appropriate value, in the case of FIG. 13, the conveyor roller 1c rotates with a weak torque received from the sub gear train even when the clutch 107c is in the OFF state (not connected). can do.

  In FIG. 7 (comparative example) already described, the rotational driving force is not applied from the feed mechanism 100 to the conveyor roller 1c in order to prevent double feeding. For this reason, a braking force Fk is generated in the medium due to friction from the stopped conveyor roller 1c. The feed force (Fa + Fb) and the brake force Fk of the conveyor rollers 1a and 1b are very small and unstable force when the remaining amount of the medium is small, and Fa + Fb ≦ Fk is satisfied, and medium non-feed without medium supply occurs. There is a case. On the other hand, in FIG. 11 (this embodiment), a rotational driving force of a weak torque (second torque) is continuously applied from the feed mechanism 200 to the conveyor roller 1c. Accordingly, when the remaining amount of the medium is small, the conveyor roller 1c can rotate, and when the lowermost medium 13a is moved in the medium transport direction by the conveyor rollers 1a and 1b, the conveyor roller 1c also rotates in the feed direction. Therefore, in this embodiment, the braking force Fk in the −y direction that causes the non-feed in FIG. 7 (comparative example) becomes the feed force Fc in the + y direction, and the medium non-feed of the lowest-order medium 13a. Is unlikely to occur. Further, even when the lowest medium 13a moves and the second lowest medium 13b comes into contact with the conveyor roller 1c, the feed force due to the weak torque applied to the medium 13b is the contact force between the medium 13b and the conveyor roller 1c. Combined with the weak pressure, it is sufficiently weak that the possibility of generating double feed is low.

  FIG. 14 shows the relationship between the medium length of the medium (when the medium length is in the y-direction region occupied by the conveyor rollers 1a to 1c and short in the y direction) and the conveyor rollers 1a to 1e in the medium supply device according to the present embodiment. It is a schematic side view shown. The operation of the conveyor roller 1c when a large number of media are stacked as shown in FIG. 14 will be described. Note that the conveyor roller 1b that transmits the driving force by connecting the clutch gears 105b and 106b with the clutch 107b turned on is the same as in FIG. In the case of FIG. 14, the second medium 13b from the lowest position is prevented from being conveyed in the + y direction by the retard roller 22 that applies a deterrent to the tip of the medium 13b.

  The conveyor roller 1c in contact with the second lowest medium 13b is subjected to a large contact pressure that generates the weight of the stacked medium, so that a large torque is required to rotate the conveyor roller 1c. . However, as described above, the torque transmitted to the conveyor roller 1c is very weak depending on the set value of the torque limiter 201, so that the conveyor roller 1c is apparently stopped. At this time, the conveyor roller 1c is apparently stopped, but attempts to convey the second medium 13b from the lowest position with the second torque transmitted by the set value of the torque limiter 201. Since the force is weaker than the first torque, double feed is not generated. Further, since the structure is such that double feeding is unlikely to occur, the set value of the deterring force of the retard roller 22 can be set to a weak deterring force that does not cause damage to the medium. In FIG. 14, the feed force Fc ′ due to the second torque is very weak compared to the feed force Fc ″ generated when the conveyor roller 1c tries to convey with the first torque. Therefore, the set value of the deterring force of the retard roller 22 can be set to an appropriate deterring force that can prevent both double feeding and medium damage.

<< 2-3 >> Effect As described above, according to the medium supply device according to the present embodiment, a strong torque can be transmitted to the drive gear train of the conveyor roller via the clutch 107 (107a to 107e). Main gear train and a sub gear train capable of transmitting a weak torque via the torque limiter 201 (201b to 201e) (that is, by two parallel gear trains), and the clutch 107 (107a to 107e) By turning ON the ON state, there is a function when strong torque transmission is required, and the occurrence of medium non-feed that may occur when the conveyor roller must be stopped as a measure to prevent double feed The effect that it can prevent is acquired.

<< 3 >> Modified Examples The medium supply apparatus to which the present invention is applied can be attached to various apparatuses as an external paper feeding apparatus. For example, the present invention can be applied to a copying machine, a facsimile machine, a multi-function peripheral device (MFP), etc., which are devices having a function of forming (printing) an image on a recording medium.

  1 (1a to 1e) Conveyor roller, 10 First separation part, 11a Medium path (gap), 20 Second separation part (retard mechanism), 21 Feed roller, 22 Retard roller, 30 Feed roller pair, 31, 32 roller, 40 control unit, 41 first medium position sensor, 42 second medium position sensor, 50 host device, 100, 200 feed mechanism, 101 motor, 102 motor gear, 103 (103a to 103e) idle gear, 104 (104a to 104d) idle Gear, 105, 106 (105a, 106a, 105b, 106b, 105c, 106c, 105d, 106d, 105e, 106e) Clutch gear, 107 (107a-107e) Clutch, 108 (108a-108e) Roller gear, 2 1 (201b~201e) torque limiter, 202 (202b~202e) idle gear, 203 (203b~203e) idle gear, 204 (204a~204e) roller gear.

Claims (7)

A plurality of conveyor rollers that are arranged in the medium conveying direction and convey the medium stacked at the medium loading position in order from the bottom;
A driving force generator for generating a driving force;
A main gear train that transmits a driving force generated by the driving force generation unit as a first torque to each of the plurality of conveyor rollers via a plurality of clutches corresponding to the plurality of conveyor rollers; and the driving force generation unit. A sub-gear train that transmits the generated driving force to one or more of the plurality of conveyor rollers as a second torque that is weaker than the first torque via one or more torque limiters. A roller drive gear train;
A medium supply apparatus comprising:   The medium supply device according to claim 1, wherein the one or more conveyor rollers are conveyor rollers other than the most downstream conveyor roller in the medium conveyance direction.   The medium supply device according to claim 1, wherein the one or more torque limiters respectively transmit the second torque to the one or more conveyor rollers of the plurality of conveyor rollers. .   And a controller that switches the plurality of clutches to a connected state in which the first torque is transmitted or a disconnected state in which the first torque is not transmitted, based on a medium length of the loaded medium. The medium supply device according to any one of claims 1 to 3.   The control unit engages clutches corresponding to a predetermined number of conveyor rollers on the downstream side in the medium transport direction among the plurality of conveyor rollers, and is connected to an upstream conveyor other than the predetermined number of downstream conveyor rollers. The medium supply device according to claim 4, wherein a clutch corresponding to the roller is brought into a non-connected state.   6. The medium supply device according to claim 5, wherein the predetermined number of conveyor rollers on the downstream side are a part of the conveyor rollers arranged within a medium length range of the stacked media.   The medium supply apparatus according to claim 4, wherein the control unit receives medium length information indicating the medium length from an upper apparatus.

Images