JP2016204119A - Paper medium feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper medium feeding device which loads and conveys a plurality of mediums sequentially from the lowest medium of the loaded mediums, and stably conveys the lowest medium at all times regardless of the amount of the loaded mediums.SOLUTION: A paper medium feeding device is provided with a rear end guide part 6 for guiding a rear end 1c of a loaded medium 1. The rear end guide part 6 comprises a base surface provided horizontally and a guide surface for lifting the rear end 1c of the loaded medium 1. The guide surface is coupled to the base surface openably and closably and energized by a torsion spring in an opening direction. The lifting amount of the rear end 1c of the loaded medium 1 by the guide surface is changed by changing an opening/closing angle between the guide surface and the base surface according to the amount of the loaded mediums 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a medium feeding device for sequentially transporting stacked media and supplying them to a printing apparatus or the like.

  2. Description of the Related Art Conventionally, medium feeding apparatuses include a medium feeding apparatus that stacks and sets a plurality of media and sequentially conveys the medium from the lowest medium so that the medium can be replenished from above. Japanese Patent Laying-Open No. 2000-255811 (Patent Document 1) shows such a paper feeding device. That is, according to Patent Document 1, a rear end portion of a medium stacked at a predetermined position is appropriately lifted by a sheet guide member (hereinafter referred to as a rear end guide), and a front end portion of the lowest medium is transported by a feed roller or the like. A conveying force is applied to the medium by contacting the medium. Then, the lower level medium other than the lowest level medium conveys only the lowest level medium by being pressed by a leading end guide that regulates the leading end side of the medium in the medium setting unit.

  Here, the effect of lifting the sheet by the rear end guide can reduce the frictional resistance that obstructs the medium conveyance by reducing the contact surface between the medium and the conveying means such as the feed roller. At the same time, the weight distribution of the loaded media is moved to the leading end side, and the structure that strongly presses the lowest media to the conveying means is also generated.

  However, in order to suppress lower media other than the lowest media with only the front end guide, it is necessary to physically set the gap provided by the front end guide and the conveying means to be 1 to 2 media. Therefore, setting is difficult when using media having various thicknesses in the same apparatus, particularly when using a thin media.

  FIG. 7 is a side view of a main part of a conventional medium feeding device. This medium feeding device conveys in order from the lowest medium, and has a structure in which the rear end of the medium 31 is lifted by the rear end guide 36. As shown in FIG. 7, in addition to the front end guide portion 32, a medium separating means 34 is generally provided on the downstream side of the medium conveyance, which is a separation member having a large friction coefficient and suppresses the medium 31 other than the lowest medium by the frictional force. . That is, a first separation unit 37 serving as a medium separation unit that divides the lower medium 31 including the lowest medium and the upper medium 31 by a physical gap formed by the tip guide unit 32, and a downstream is provided. A second separation part 34 is provided as a medium separation means by friction. In this way, among the several media that have passed through the first separation unit 37, only the lowest-order medium is further separated by the second separation unit 34 and thereafter conveyed downstream by the facing roller 35 or the like.

JP 2000-255811 A

  However, according to the technique according to Patent Document 1, when the rear end of the medium 31 is lifted by the rear end guide, as described above, the medium is conveyed by reducing the frictional resistance and strengthening the lowermost medium to the conveying means such as the feed roller 33. A good effect such as an increase in force can be obtained, and at the same time, a phenomenon occurs in which the friction force between the stacked media increases. In other words, since the weight of the upper medium 31 is always applied to the lower medium in the stacked medium 31, a stronger inter-medium friction force is generated between the lower media as the medium loading amount increases. As a result, the weight is concentrated on the leading edge due to the lifting effect of the trailing edge guide, so that stronger friction between the media occurs, making it difficult to separate the lowest medium to be transported from other lower media. Will occur.

  On the other hand, when the rear end of the medium 31 is not lifted by the rear end guide, the frictional resistance increases and at the same time the pressing of the lowest level medium and the conveying means is weakened. In particular, when the loaded medium 31 is used without being replenished and becomes the last few to one sheet, the pressing force between the medium 31 and the conveying means becomes very weak, and there is a so-called “non-feed” state in which the medium is not conveyed. Will occur.

  That is, when the rear end guide lifts the rear end of the medium 31, when the medium stacking amount is large, the medium 31 is pressed against the transport means by the weight of the medium itself, and a strong transport force is obtained. It is better not to adopt it because it causes a decrease in separability. On the other hand, when the amount of loaded medium is small, it is effective to obtain a necessary conveying force by strengthening the pressing to the conveying means. In this manner, lifting the rear end of the medium 31 by the rear end guide has a problem that there is a contradictory relationship between the case where the medium loading amount is large and the case where the medium loading amount is small.

  The problem to be solved by the present invention is to provide a medium feeding device for loading a plurality of media and setting them in order and transporting them in order from the lowest media of the stacked media so that the media can be replenished from above. It is possible to provide a medium feeding device capable of always stably transporting the lowest level medium regardless of the amount.

  In order to solve the above-described problems, a medium feeding apparatus according to the present invention is a medium feeding apparatus that stacks a plurality of media and sequentially conveys the media from the lowest level of the loaded medium. An end guide portion is provided, and the rear end guide portion includes a horizontal plate-like base surface and a plate-like guide surface that lifts the rear end of the loading medium, and one side of the guide surface is the base. The guide surface is connected to one side of the surface so as to be openable and closable, and the guide surface is urged in the opening direction by the urging means, and the guide surface and the base surface are opened and closed according to the amount of the loading medium. The amount of lifting of the rear end of the loading medium by the guide surface is changed by changing the angle.

  According to the present invention having the above configuration, when the amount of loaded media is large due to the biasing force of the spring and the weight balance of the loaded media regardless of the weight of the medium used, the rear end of the medium is lifted. However, if the amount of the loaded medium decreases, the trailing edge guide rises accordingly and causes the trailing edge of the medium to be lifted. As a result, a medium feeding device that prevents the misfeed can be obtained by changing the lifting height of the trailing edge of the medium according to the weight of the loaded medium without using a large-scale mechanism such as an actuator or a sensor for detecting the loading amount. The effect of being able to be obtained.

1 is a side view of an essential part of a medium feeding device according to a first embodiment of the present invention. It is a side view which shows the rear-end guide part regarding 1st Embodiment. It is explanatory drawing which shows the isolation | separation operation | movement of the isolation | separation part regarding 1st Embodiment. It is explanatory drawing which shows operation | movement of the rear-end guide part regarding 1st Embodiment. It is a side view which shows operation | movement of the loading part regarding 1st Embodiment. It is explanatory drawing which shows the relationship between medium loading amount, medium conveyance force, and medium double feeding force. It is a principal part side view of the conventional medium feeding apparatus.

(First embodiment)
FIG. 1 is a side view of an essential part of a medium feeding device according to a first embodiment of the present invention. The medium feeding device 100 includes a stacking unit 10, a separation unit 4, and a counter roller unit 5 along the conveyance direction indicated by an arrow A of the medium 1. The medium feeding device 100 stacks a plurality of media 1 and sets them on the stacking unit 10 and separates and conveys them sequentially from the lowest medium 1a of the medium set so that the medium 1 can be replenished from above. The medium 1 is stacked on the horizontal medium mounting surface 11 of the stacking unit 10.

  In the transport direction indicated by the arrow A, the front side 1 b of the stack medium 1 is regulated by the front end guide section 2 of the stack section 10. The leading end guide portion 2 of the stacking portion 10 is provided substantially vertically in contact with the front surface side 1b of the stacking medium 1, the lower portion is bent in the transport direction A, and the lowermost end is a feed roller 3 described below. A physical gap is formed between them. A feed roller 3 that is driven by a motor (not shown) and rotates in the transport direction A is provided on the transport direction A side of the stack medium 1 in the stacking unit 10, and the lowest-order medium 1 a in the stack medium 1 comes into contact therewith. Yes.

  A separation unit 4 is provided downstream of the front end guide unit 2 of the stacking unit 10. Furthermore, in order to deliver the separated lowermost medium 1a from the paper feeding device 100 to a printing device (not shown), a counter roller unit 5 including a pair of upper and lower opposing rollers 5a and 5b that are driven by a motor (not shown) is provided. Yes.

  Further, a rear end guide portion 6 is provided at the rear end portion of the stack medium 1 in the stack portion 10. The rear end guide portion 6 can be slid forward and rearward in the transport direction A, and can be fixed at a predetermined position. It can move to the end position.

  The separation unit 4 is positioned below the transport medium surface 12 and the transport roller 4a above the transport medium surface 12. The separation unit 4 is in contact with the transport roller 4a by a spring (not shown) and is pressed by a torque limiter (not shown). A retard roller 4b is provided with a rotational load.

  The leading edge guide section 2 in the stacking section 10 forms first medium separating means that divides the lower medium including the lowest medium 1a and its upper medium by the physical gap created by the leading edge guide section 2. The separation unit 4 forms a second medium separation unit that is provided downstream of the separation unit 4 and separates the lowest medium 1a by friction. Of the several media that have passed through the first medium separating means, only the lowest medium is further separated by the second medium separating means and conveyed downstream.

  FIG. 2 is a side view showing a rear end guide portion according to the first embodiment. The rear end guide portion 6 guides the medium rear end 1c of the loaded medium 1 as described above. The rear end guide portion 6 includes a plate-shaped square guide surface 6a that lifts the medium rear end 1c of the loaded medium 1 and a plate-shaped square base surface 6b that is in contact with the medium placement surface 11 and provided horizontally. Have.

  One side of the guide surface 6a is coupled to one side of the base surface 6b in the transport direction A by a hinge 6e as a coupling means, that is, can be opened and closed. The angle formed by the guide surface 6a and the base surface 6b is restricted to an angle that can be opened and closed within a range of a rotation restriction angle, which will be described later, which is the upper limit of the movable range. The guide surface 6a is pressed in the direction of the rear end 1c of the medium as an opening direction by a pushing force Fsp of a torsion spring 6c as an urging means.

  A spring adjustment cam 6d is provided near the hinge 6e of the base surface 6b as adjustment means for adjusting the push-up force Fsp of the torsion spring 6c that pushes up the guide surface 6a. The spring adjustment cam 6d is rotatably attached to the base surface 6b so as to support one end of the torsion spring 6c, and the push-up force Fsp can be adjusted by rotating.

  Thus, by changing the opening / closing angle between the guide surface 6a and the base surface 6b in accordance with the amount of the loaded medium 1, it is possible to change the lift amount of the medium rear end 1c of the loaded medium 1 by the guide surface 6a.

  Next, the operation of the separation unit 4 relating to the present embodiment will be described. FIG. 3 is an explanatory diagram illustrating the separation operation of the separation unit according to the first embodiment. As shown in FIG. 3A, when there is no medium 1 at the opposed roller point 14 between the transport roller 4a and the retard roller 4b, that is, before the medium 1 reaches the separation section 4, the retard roller 4b It is passively rotated by the transport roller 4a.

  Next, as shown in FIG. 3B, when the medium 1 that has passed through the front end guide portion 2 reaches the opposing roller point 14, the lowest medium 1a is first sandwiched between the transport roller 4a and the retard roller 4b. The medium 1a is pressed against the transport roller 4a by the retard roller 4b. Here, the transport roller 4a is a rubber material having a high friction coefficient, has a strong frictional force with the lowest medium 1a, and generates a transport force F1. On the other hand, the rotational load F2 (hereinafter referred to as braking force) applied to the retard roller 4b by the torque limiter is set to be smaller than F1, so the retard roller 4b follows the transport roller 4a and transports the lowest medium 1a. .

  Next, as shown in FIG. 3C, when the second medium 1b in contact with the lowest-order medium 1a also enters the counter roller point 14 due to the inter-medium friction, the inter-medium friction F3 occurs between the mediums 1a and 1b. The brake force F2 is set to be larger than the medium friction F3. That is, due to the relationship of F1> F2> F3, the second medium 1b is stopped by the retard roller 4b and separated from the lowest medium 1a.

  Next, the operation of the rear end guide portion 6 relating to the present embodiment will be described. FIG. 4 is an explanatory view showing the operation of the rear end guide part according to the first embodiment. In the rear end guide portion 6, the push-up force Fsp that the torsion spring 6c pushes up the guide surface 6a is “force to push up the weight of the guide surface 6a” + “force to push up the rear end of several sheets of media”. Here, since the “force for pushing up the trailing edge of several media” differs depending on the type of media (medium width, media thickness, media density), it can be adjusted by the spring adjusting cam 6d according to the medium to be used. it can.

  As shown in FIG. 4, when the amount of the loaded medium 1 is large, the guide surface 6a is pushed by the weight of the loaded medium 1 and is at the lower limit of the movable range indicated by the broken line. When the amount of the loaded medium 1 is small, the guide surface 6a is at the upper limit of the movable range indicated by the solid line by the push-up force Fsp. Thus, the movable range θ of the guide surface 6a is between the movable range lower limit and the movable range upper limit.

  FIG. 5 is a side view showing the operation of the stacking unit according to the first embodiment. As shown in FIG. 5A, when the amount of the loaded medium 1 is large, a force equal to or higher than the push-up force Fsp is applied from the loaded medium 1, so that the guide surface 6a is closed and becomes substantially horizontal. The angle formed by the guide surface 6a and the base surface 6b is approximately 0 degrees.

  When the medium is used without being replenished as shown in FIG. 5B and the number of the stacked media 1 is reduced and the weight of the stacked media 1 is reduced, the guide surface 6a is gradually moved by the pushing force Fsp by the torsion spring 6c. get up. That is, the angle θ between the guide surface 6a and the base surface 6b is increased, and the lift amount of the media rear end 1c of the stack medium 1 by the guide surface 6a is increased. Finally, the guide surface 6a reaches the rotation restriction angle as the upper limit of the movable range, and pushes up the medium rear end 1c. The rotation restriction angle of the guide surface 6a is desirably about 50 ° to 80 ° at which the rear end 1c of the guide surface is liable to generate a sliding force.

  FIG. 6 is an explanatory diagram showing the relationship between the medium loading amount, the medium conveying force, and the medium double feeding force. In the following description, when the rear end 1c of the medium is lifted by the rear end guide with the conventional angle fixed, when the rear end 1c of the medium is not lifted, and when the rear end guide unit 6 according to the present embodiment The case where the end 1c is lifted will be described in comparison.

  First, FIG. 6A shows the relationship between the medium carrying force F4 by the feed roller 3 of the stacking unit 10 and the medium stacking amount M according to the first embodiment. The vertical axis represents the medium conveyance force F4 of the stacking unit 10, and the horizontal axis represents the medium loading amount M of the stacking unit 10. The conveying force that the lowest medium 1a is obtained from the feed roller 3 increases as the medium loading amount M increases, and decreases as the medium loading amount M decreases. Therefore, if the amount of the loaded medium 1 decreases depending on the state of the medium used (medium loaded amount M is small), the frictional resistance with the surroundings may exceed the conveying force and the medium may not be fed (Y line in the figure). This corresponds to the case where there is no rear end guide 36 in the conventional medium feeding device.

  On the other hand, when the rear end of the medium is lifted by the rear end guide portion 6 in order to prevent this medium non-feeding, the pressing force of the lowest-order medium 1a against the feed roller 3 becomes strong, so that the conveying force F4 increases and the medium non-feed Can be reduced (X-rays in the figure). This corresponds to the case where there is the rear end guide 36 in which the angle between the guide surface and the base surface is fixed in the conventional medium feeding device.

  Here, when the rear end guide portion 6 relating to the present embodiment is used, the same relationship as that of the Y line is maintained when the guide surface 6a is in a substantially horizontal state. Then, the weight of the loaded medium 1 becomes lighter and the line Z is traced starting from the point P where the guide surface 6a starts to rise, and when it rises to the rotation restriction angle, the same relationship as the line X is obtained (Y line -P point- in the figure). Z line). The medium conveyance limit area Q is the minimum necessary medium conveyance force F4.

  Next, FIG. 6B shows the relationship between the force (multifeed force F5) to be transported by the lowest medium 1a and the second medium 1b and the medium stacking amount M according to the first embodiment. Show. The double feed force F5 of the second medium 1b is also proportional to the medium load amount M, similarly to the transport force F4 of the lowest medium 1a. Here, in order to reduce the size of the apparatus, the separation unit 4 needs to be installed at a position before the media rear end 1c passes through the stacking unit 10.

  The brake force F2 described with reference to FIG. 3 is actually generated from the “medium friction F3 generated in the separation unit 4” and the medium weight stacked on the second medium 1b in the stacking unit 10. If it is not larger than the sum of the frictional force between the media (the frictional force between the laminated parts) F6 ", the medium double feed occurs. Since the brake force F2 cannot be increased without limit due to damage to the medium 1 or motor torque limitation, the limit of the brake force F2 that can be set to prevent double feed is F2max> intermediate friction F3 + intermediate friction between laminated parts It is necessary to limit the medium loading so that the force F6 is obtained.

  As shown in FIG. 6B, the lifting of the medium trailing edge 1c by the conventional trailing edge guide 36 is affected by the medium loading amount M, but the trailing edge guide portion 6 according to the present embodiment has a medium loading amount M of When the number is large, the rear end 1c of the medium is not lifted, which is the same as when the rear end guide is not used (Y line in the figure).

  As described above, according to the first embodiment, it is possible to lift the rear end optimally according to the medium loading amount with a simple structure without using an actuator or a sensor for detecting the loading amount, and the medium loading limit The effect of preventing misfeeding during the conveyance of the medium without adversely affecting the recording medium can be obtained.

  In the first embodiment, the medium conveying means is a roller, but the present invention can also be applied to an apparatus using an endless belt. Moreover, although the retard roller which gave the rotational load was used as a separation means, a non-rotating member and a reverse rotation roller are applicable.

DESCRIPTION OF SYMBOLS 1 Medium 2 Front end guide part 3 Feed roller 4 Separation part 5 Opposite roller part 6 Rear end guide part 6a Guide surface 6b Base surface 6c Torsion spring 6d Spring adjustment cam 6e Hinge 10 Stacking part 100 Paper feeding device

Claims (7)

In a medium feeding device that stacks a plurality of media and conveys them in order from the lowest medium of the loaded media,
A rear end guide portion for guiding a rear end of the loading medium is provided;
The rear end guide part is composed of a plate-shaped base surface provided horizontally and a plate-shaped guide surface for lifting the rear end of the loading medium,
One side of the guide surface is coupled to one side of the base surface so as to be openable and closable by coupling means, and the guide surface is urged in an opening direction by urging means,
According to the amount of the loaded medium, the amount of lifting of the trailing edge of the loaded medium by the guide surface is changed by changing an opening / closing angle between the guide surface and the base surface. apparatus. When the weight of the loading medium is large, the guide surface is pushed by the weight of the loading medium, and the angle formed by the guide surface and the base surface is approximately 0 degrees,
When the weight of the loading medium decreases, the guide surface increases an angle between the guide surface and the base surface by the urging unit, and increases a lifting amount of the trailing edge of the loading medium by the guide surface. The medium feeding device according to claim 1.   3. The medium feeding device according to claim 1, wherein an angle formed between the guide surface and the base surface has a rotation restriction angle that is an upper limit of a movable range.   The medium feeding device according to claim 3, wherein the rotation restriction angle is about 50 ° to 80 °.   2. The medium feeding apparatus according to claim 1, wherein the urging unit includes an adjusting unit that adjusts the strength of the urging unit.   6. The medium feeding apparatus according to claim 5, wherein the biasing means is a torsion spring, and the adjusting means is a cam that supports one end of the torsion spring. The medium feeding device according to claim 1, wherein the rear end guide portion is movable in a conveyance direction of the medium so as to conform to a length of the medium.

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