CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2017-005569, which was filed on Jan. 17, 2017, the disclosure of which is herein incorporated by reference in its entirety.

BACKGROUND
Technical Field

The following disclosure relates to a sheet conveying apparatus configured to covey sheets such as paper.

Description of Related Art

There is known an apparatus configured to convey sheets and having a first supply roller (roller) supported at a distal end of a pivotable arm. The roller is rotated while being held in contact with a front surface of an uppermost one of the sheets stored in a supply tray, so that the uppermost sheet is conveyed.

SUMMARY

In the known apparatus, an angle defined by the arm and the sheets in the supply tray on an upstream side of the sheets in a sheet conveyance direction, namely, a contact angle, changes in a time period from a fully loaded state of the supply tray in which a maximal amount of the sheets are loaded on the supply tray to a near empty state of the supply tray in which a minimal amount of the sheets are loaded on the supply tray. Specifically, the contact angle increases with a decrease in the amount of the sheets loaded on the supply tray. As a result, a pressing force applied by the roller to the sheets becomes large, so that a plurality of sheets are likely to be conveyed in an overlapping state, namely, multiple feeding of the sheets tends to occur.

Accordingly, one aspect of the disclosure relates to a sheet conveying apparatus capable of preventing or reducing an occurrence of multiple feeding of sheets in a time period from the fully loaded state to the near empty state.

In one aspect of the disclosure, a sheet conveying apparatus including: a container for storing a stack of a plurality of sheets; a roller rotatable about a rotation shaft parallel to the plurality of sheets stored in the container and configured to convey the plurality of sheets one by one in a conveyance direction by rotating about the rotation shaft while being held in contact with a front surface of the plurality of sheets stored in the container, an arm including a supporter that rotatably supports the roller, the arm being pivotable about an arm pivot shaft parallel to the rotation shaft while the supporter is located downstream of the arm pivot shaft in the conveyance direction, and a presser plate configured to press the plurality of sheets stored in the container toward the roller and to be pivotable about a presser-plate pivot shaft parallel to the rotation shaft, wherein the presser plate includes a bend portion disposed between: a downstream end of the presser plate in the conveyance direction; and the presser-plate pivot shaft, the bend portion being bent or bendable, wherein a distal portion which is a portion of the presser plate ranging from the downstream end to the bend portion and which faces the roller and a basal portion which is a portion of the presser plate ranging from the bend portion to the presser-plate pivot shaft define a bend angle when the distal portion and the basal portion are bent, the bend angle being an angle defined on one side of the presser plate that is farther from the arm, the bend angle being maintained at an obtuse angel when a state of the container is a first-amount loaded state in which a first amount of the plurality of sheets are loaded on the container, and wherein a contact angle of the arm and the plurality of sheets at a contact position, at which the arm and the plurality of sheets on the presser plate contact, is smaller than a maximum angle in a time period in which the state of the container changes from a maximally loaded state in which a maximal amount of the plurality of sheets are loaded on the container to the first-amount loaded state, the maximum angle being an angle defined by: (i) the basal portion in the maximally loaded state; and (ii) the arm the roller of which contacts the presser plate which is the presser plate in the maximally loaded state and on which it is assumed that the plurality of sheets are not loaded in the maximally loaded state.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features, advantages, and technical and industrial significance of the present disclosure will be better understood by reading the following detailed description of embodiments, when considered in connection with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a printer according to a first embodiment, the view being taken along a plane parallel to a vertical direction;

FIG. 2 is a cross-sectional view showing a fully loaded state of a sheet supply tray of the printer according to the first embodiment, the view being taken along the plane parallel to the vertical direction;

FIG. 3 is a cross-sectional view showing a state of the sheet supply tray of the printer according to the first embodiment in a time period from the fully loaded state till before reaching a near empty state, the view being taken along the plane parallel to the vertical direction;

FIG. 4 is a cross-sectional view showing the near empty state of the sheet supply tray of the printer according to the first embodiment, the view being taken along the plane parallel to the vertical direction;

FIG. 5 is a cross-sectional view showing the fully loaded state of the supply tray of a printer according to a second embodiment, the view being taken along the plane parallel to the vertical direction;

FIG. 6 is a cross-sectional view showing a state of the supply tray of the printer according to the second embodiment in the time period from the fully loaded state till before reaching the near empty state, the view being taken along the plane parallel to the vertical direction;

FIG. 7 is a cross-sectional view showing the near empty state of the sheet supply tray of the printer according to the second embodiment, the view being taken along the plane parallel to the vertical direction;

FIG. 8 is a cross-sectional view showing the fully loaded state of the supply tray of a printer according to a third embodiment, the view being taken along the plane parallel to the vertical direction;

FIG. 9 is a cross-sectional view showing a state of the sheet supply tray of the printer according to the third embodiment in the time period from the fully loaded state till before reaching the near empty state, the view being taken along the plane parallel to the vertical direction; and

FIG. 10 is a cross-sectional view showing the near empty state of the sheet supply tray of the printer according to the third embodiment, the view being taken along the plane parallel to the vertical direction.

DETAILED DESCRIPTION OF THE EMBODIMENTS
First Embodiment

As shown in FIG. 1, a printer 1 according to a first embodiment includes: a supply tray 10 capable of storing a stack of a plurality of sheets 100; a conveyor 20 configured to convey an uppermost one of the sheets 100 stored in the supply tray 10 along a conveyance path R; a recording portion 30 configured to perform recording on the sheet 100 conveyed by the conveyor 20; a platen 40 which is opposed to the recording portion 30; an output tray 50 for receiving the sheet 100 which has been conveyed by the conveyor 20; a controller 60 configured to control the conveyor 20, the recording portion 30, and other devices; and a sensor 70 configured to detect an amount of the sheets 100 loaded or stacked on the supply tray 10.

The conveyor 20 includes: a roller 11 disposed so as to be in contact with an uppermost one of the sheets 100 stored in the supply tray 10; a roller pair 21 disposed upstream of the recording portion 30 in the conveyance path R; a roller pair 22 disposed downstream of the recording portion 30 in the conveyance path R; and guide plates 20g that define the conveyance path R.

The roller 11 has a rotation shaft 11x parallel to the sheets 100 stored in the supply tray 10. The roller 11 rotates about the rotation shaft 11x while being in contact with a front surface of the uppermost one of the sheets 100 stored in the supply tray 10, so as to convey the uppermost sheet 100 in a conveyance direction.

The supply tray 10 has a separation wall 10w. The separation wall 10w is constituted by one of four walls of the supply tray 10 that is located downstream of the roller 11 in the conveyance direction. When a plurality of sheets 100 are supplied by rotation of the miler 11, the separation wall 10w contacts one of the plurality of sheets 100 which is farthest from the roller 11 and gives the farthest sheet 100 to a resistance, so as to separate the uppermost sheet 100 from other sheets. To this end, the separation wall 10w is provided with a separation member and separation rollers (not shown). The separation member may be a plate member formed of a material having a high frictional resistance such as cork or rubber or may be a member having a plurality of protrusions formed of resin or metal. Feed rollers are disposed so as to be opposed to the separation rollers. The feed rollers always rotate forwardly to convey the sheet 100 in the conveyance direction. The separation rollers rotate forwardly when one sheet 100 is nipped between the separation rollers and the feed rollers and rotate reversely when a plurality of sheets 100 are nipped therebetween.

The rotation shaft 11x of the roller 11 is rotatably supported by a distal end (i.e., a supporter 12a) of the arm 12. The arm 12 is pivotable about a pivot shaft 12x provided at a basal end of the arm 12 located opposite to the distal end while the supporter 12a is located downstream of the pivot shaft 12x in the conveyance direction. The pivot shaft 12x is parallel to the rotation shaft 11x and is rotatably supported by a housing (not shown) of the printer 1.

The arm 12 supports gears 12g1-12g9. The gears 12g1-12g9 are in mesh with one another. The gear 12g1 is fixed to the rotation shaft 11x, the gear 12g9 is in mesh with a shaft 11Mx of a drive motor 11M, and the gears 12g2-12g8 connect the gear 12g1 and the gear 12g9. When the drive motor 11M is driven, the gears 12g1-12g9 are rotated, so that a drive force of the drive motor 11M is transmitted to the roller 11, and the roller 11 is rotated.

The supply tray 10 pivotably supports: a presser plate 13 for pressing the sheets 100 stored in the supply tray 10 toward the roller 11; and a push-up member 14 for pushing up the presser plate 13 from below so as to pivot the presser plate 13. A pivot shaft 13x of the presser plate 13 and a pivot shaft 14x of the push-up member 14 are parallel to the rotation shaft 11x and are rotatably supported by the supply tray 10. The presser plate 13 is pivotable about the pivot shaft 13x while its downstream end 13t is located downstream of the pivot shaft 13x in the conveyance direction. The push-up member 14 is pivotable about the pivot shaft 14x while its downstream end 14t is located downstream of the pivot shaft 14x in the conveyance direction.

The presser plate 13 includes, between the downstream end 13t and the pivot shaft 13x, a bend portion 13c which is bendable. The presser plate 13 includes a distal member 13a shaped like a plate and having the downstream end 13t and a basal member 13b shaped like a plate and at which the pivot shaft 13x is provided. A boundary between the distal member 13a and the basal member 13b corresponds to the bend portion 13c.

Front surfaces 13a1, 13b1 of the distal member 13a and the basal member 13b which face the roller 11 respectively constitute a distal region 13A and a basal region 13B. The distal region 13A is a region ranging from the downstream end 13t to the bend portion 13c. The basal region 13B is a region ranging from the bend portion 13c to the pivot shaft 13x.

A rotation shaft 13ax is provided at an upstream end of the distal member 13a which is located opposite to the downstream end 13t in the conveyance direction and at which the bend portion 13c is provided. The rotation shaft 13ax is rotatably supported by a downstream end of the basal member 13b which is located opposite to an upstream end of the basal member 13b in the conveyance direction at which the pivot shaft 13x is provided. That is, the distal member 13a and the basal member 13b are connected to each other through the bend portion 13c such that a bend angle α is changeable. In the present embodiment, the bend angle α is an angle defined, on one side of the presser plate 13 that is farther from the arm 12, by a portion of the presser plate 13 corresponding to the distal region 13A and a portion of the presser plate 13 corresponding to the basal region 13B.

An extending portion 13ae is provided on a back surface 13a2 (opposite to the front surface 13a1) at the upstream end of the distal member 13a. The extending portion 13ae extends in a direction which intersects the distal region 13A and which is directed from the bend portion 13c toward the pivot shaft 13x.

The push-up member 14 is configured to pivot about the pivot shaft 14x by control of the controller 60 while its downstream end 14t is held in contact with the back surface 13b2 of the basal member 13b, so as to cause the basal member 13b to be pivoted about the pivot shaft 13x. The controller 60 is configured to receive a signal from the sensor 70 and to drive the pivot shaft 14x in accordance with the amount of the sheets 100 stacked on the supply tray 10, thereby controlling a posture of the push-up member 14 and accordingly a posture of the presser plate 13.

Referring next to FIGS. 2-4, there will be explained operations of the presser plate 13 and the push-up member 14 in a time period in which a state of the supply tray 10 changes from a state in which a maximal amount of the sheets 100 are loaded on the supply tray 10 (hereinafter referred to as “fully loaded state” where appropriate) to a state in which a first amount of the sheets 100 are loaded on the supply tray 10, namely, a single sheet is loaded on the supply tray 10 in the present embodiment (hereinafter referred to as “mar empty state” where appropriate). The fully loaded state is one example of “maximally loaded state”, and the near empty state is one example of “first-amount loaded state”.

As shown in FIG. 2, the bend angle α is equal to 180° in the fully loaded state. In this instance, the downstream end 14t of the push-up member 14 is held and sandwiched by and between the extending portion 13ae and the basal member 13b.

In a time period from the fully loaded state till before reaching the near empty state, as the amount of the sheets 100 stacked on the supply tray 10 decreases, the push-up member 14 is pivoted by control of the controller 60, as shown in FIG. 3. In this instance, the downstream end 14t of the push-up member 14 moves in a direction directed from the bend portion 13c toward the pivot shaft 13x along the back surface 13b2 of the basal member 13b while the downstream end 14t is interposed between the extending portion 13ae and the basal member 13b. The push-up member 14 pushes up the downstream end of the basal member 13b, whereby the basal member 13b is pivoted about the pivot shaft 13x toward the arm 12. The downstream end 14t and the extending portion 13ae are shaped such that, in the time period from the fully loaded state till before reaching the near empty state, the distal member 13a is moved upward with its posture kept horizontal and the bend angle α gradually becomes smaller. More specifically, in the time period from the fully loaded state till before reaching the near empty state, the downstream end 14t of the push-up member 14 nearer to the bend portion 13c is held in contact with both of the basal member 13b and the extending portion 13ae while being sandwiched therebetween. In this instance, a force received by the distal member 13a from the sheets 100 acts on the basal member 13b through the extending portion 13ae and the push-up member 14. Thus, the posture of the distal member 13a is kept horizontal. As shown in FIGS. 2 and 3, in the time period from the fully loaded state till before reaching the near empty state, the downstream end 14t of the push-up member 14 is located at a height level higher than the extending portion 13ae, and the downstream end of the basal member 13b nearer to the bend portion 13c is located at a height level higher than the downstream end 14t of the push-up member 14. According to the positional relationship among the distal member 13a, the basal member 13b, and the push-up member 14, the downstream end 14t of the push-up member 14 is sandwiched between the basal member 13b and the extending portion 13ae with high reliability.

At the same time when the near empty state is established, the push-up member 14 moves away from between the extending portion 13ae and the basal member 13b, and the bend angle α is kept defined by contact of the extending portion 13ae and the basal member 13b, as shown in FIG. 4. That is, the downstream end 14t of the push-up member 14 is spaced apart from the extending portion 13ae and is held in contact with the lower surface (the back surface 13b2) of the basal member 13b.

Thus, the push-up member 14 functions as an angle adjuster for adjusting the bend angle α defined by the distal member 13a and the basal member 13b.

In the time period in which the state of the supply tray 10 changes from the fully loaded state to the near empty state, namely, in the time period from the fully loaded state to the near empty state, the bend angle α is maintained at an obtuse angle, and the distal region 13A is kept opposed to the roller 11.

In the time period from the fully loaded state to the near empty state, a contact angle β, i.e., an angle defined, on the upstream side in the conveyance direction, by the arm 12 and a roller-contacting portion 100a of the sheets 100 on the presser plate 13 which is in contact with the roller 11, is constant (The contact angle β may be referred to as an angle defined by the arm and the sheets at a contact position of the arm and the sheets.) That is, the contact angle β is equal to a minimum angle βmin (which is the contact angle in the fully loaded state and is equal to 0° in the present embodiment). Further, the contact angle β is kept less than a maximum angle βmax which is an angle defined, on the upstream side in the conveyance direction, by: (i) the portion of the presser plate 13 corresponding to the basal region 13B in the fully loaded state; and (ii) the arm 12 the roller 11 of which contacts the presser plate 13 which is the presser plate 13 in the fully loaded state and on which it is assumed that the sheets 100 are not loaded in the fully loaded state, i.e., the arm 12 indicated by the long dashed double-short dashed line in FIG. 2.

An angle γ defined by the portion of the presser plate 13 corresponding to the distal region 13A and the separation wall 10w is also kept constant in the time period from the fully loaded state to the near empty state.

As described above, according to the present embodiment, the contact angle β is kept less than the maximum angle βmax in the time period from the fully loaded state to the near empty state, so that it is possible to prevent a plurality of sheets from being conveyed in an overlapping state. In other words, an occurrence of multiple feeding of the sheets is obviated.

In the time period from the fully loaded state to the near empty state, the angle γ defined by the portion of the presser plate 13 corresponding to the distal region 13A and the separation wall 10w is kept constant, enabling the sheets to be conveyed with high stability.

In the time period from the fully loaded state to the near empty state, the contact angle β is larger than the minimum angle βmin. When the contact angle β becomes smaller, a pressing force of the roller 11 with respect to the sheets 100 becomes smaller, so that the sheet 100 cannot be conveyed due to a slippage between the roller 11 and the sheet 100 even when the roller 11 is rotated, namely, a feeding failure is likely to occur. According to the configuration in which the contact angle β is larger than the minimum angle βmin in the time period from the fully loaded state to the near empty state, it is possible to prevent or reduce an occurrence of the feeding failure.

In the near empty state, the contact angle β is larger than the minimum angle βmin. In this case, it is possible to prevent or reduce an occurrence of the multiple feeding of the sheets with high reliability in a situation in which the amount of the sheets 100 stacked on the supply tray 10 is small and the multiple feeding of the sheets accordingly tends to occur.

In the time period from the fully loaded state to the near empty state, the contact angle β is larger than the minimum angle βmin. In this case, it is possible to prevent or reduce an occurrence of the multiple feeding of the sheets with high reliability in the time period from the fully loaded state to the near empty state.

The presser plate 13 includes the distal member 13a having the distal region 13A and the basal member 13b having the basal region 13B. The printer 1 further includes the angle adjuster (which is a mechanism including the push-up member 14) for adjusting the bend angle α defined by the distal member 13a and the basal member 13b. In this case, the contact angle β can be maintained at an angle less than the maximum angle βmax in the time period from the fully loaded state to the near empty state, with a relatively simple configuration.

The angle adjuster is configured such that, in the time period from the fully loaded state till before reaching the near empty state, the bend angle α is gradually decreased by pivoting the push-up member 14 such that the downstream end 14t of the push-up member 14 is moved in the direction directed from the bend portion 13c toward the pivot shaft 13x while the downstream end 14t is interposed between the extending portion 13ae and the basal member 13b. Further, the angle adjuster is configured such that, when the near empty state is established, the push-up member 14 is moved away from between the extending portion 13ae and the basal member 13b, and the bend angle α is kept defined by contact of the extending portion 13ae and the basal member 13b. With this configuration, it is possible to prevent or reduce an occurrence of the feeding failure in the near empty state due to an excessive decrease of the bend angle α. In the first embodiment, at the same time when the near empty state is established, the push-up member 14 is moved away or spaced apart from the extending portion 13ae. The push-up member 14 may be spaced apart from the extending portion 13ae at other timing. For instance, the push-up member 14 may be spaced apart from the extending portion 13ae at a time point earlier than a time point when the state of the supply tray 10 reaches the near empty state. More specifically, in a time period from a first time point at which the state of the supply tray 10 is the fully loaded state to a third time point at which a second amount of the sheets 100 larger than the first amount are loaded on the supply tray 10 and which is earlier than a second time point at which the state of the supply tray 10 reaches the near empty state, the downstream end 14t of the push-up member 14 may be held in contact with the basal member 13b and the extending portion 13ae while being kept interposed therebetween. In a time period from the third time point to the second time point, the downstream end 14t of the push-up member 14 may be spaced apart from the extending portion 13ae. Also in this configuration, the posture of the distal member 13a is kept horizontal from the first time point to the second time point, and the bend angle α of the presser plate 13 is maintained. With this configuration, it is possible to prevent or reduce an occurrence of the feeding failure in the near empty state due to an excessive decrease of the bend angle α.

Second Embodiment

Referring next to FIGS. 5-7, there will be explained a printer according to a second embodiment. The printer of the second embodiment differs from the printer of the first embodiment in structures of the presser plate and the push-up member, and other structures are the same as in the first embodiment.

The supply tray 10 pivotably supports: a presser plate 213 for pressing the sheets 100 stored in the supply tray 10 toward the roller 11; and a push-up member 214 for pushing up the presser plate 213 from below so as to pivot the presser plate 213. A pivot shaft 213x of the presser plate 213 and a pivot shaft 214x of the push-up member 214 are parallel to the rotation shaft 11x and are rotatably supported by the supply tray 10. The presser plate 213 is pivotable about the pivot shaft 213x while its downstream end 213t is located downstream of the pivot shaft 213x in the conveyance direction. The push-up member 214 is pivotable about the pivot shaft 214x while its downstream end 214t is located downstream of the pivot shaft 214x in the conveyance direction.

The presser plate 213 includes, between the downstream end 213t and the pivot shaft 213x, a bend portion 213c which is bendable. The presser plate 213 includes a distal member 213a shaped like a plate and having the downstream end 213t and a basal member 213b shaped like a plate and at which the pivot shaft 213x is provided. A boundary between the distal member 213a and the basal member 213b corresponds to the bend portion 213c.

Front surfaces 213a1, 213b1 of the distal member 213a and the basal member 213b which face the roller 11 respectively constitute a distal region 213A and a basal region 213B. The distal region 213A is a region ranging from the downstream end 213t to the bend portion 213c. The basal region 213B is a region ranging from the bend portion 213c to the pivot shaft 213x.

A rotation shaft 213ax is provided at an upstream end of the distal member 213a which is located opposite to the downstream end 213t in the conveyance direction and at which the bend portion 213c is provided. The rotation shaft 213ax is rotatably supported by a downstream end of the basal member 213b which is located opposite to an upstream end of the basal member 213b in the conveyance direction at which the pivot shaft 213x is provided. That is, the distal member 213a and the basal member 213b are connected to each other through the bend portion 213c such that a bend angle α is changeable. In the present embodiment, the bend angle α is an angle defined by a portion of the presser plate 213 corresponding to the distal region 213A and a portion of the presser plate 213 corresponding to the basal region 213B, on one side of the presser plate 213 that is farther from the arm 12.

The push-up member 214 is configured to pivot about the pivot shaft 214x by control of the controller 60 while its downstream end 214t is held in contact with a back surface 213a2 of the distal member 213a (which is opposite to the front surface 213a1), so as to push up the distal member 213a. The controller 60 is configured to receive a signal from the sensor 70 and to drive the pivot shaft 214x in accordance with the amount of the sheets 100 stacked on the supply tray 10, thereby controlling a posture of the push-up member 214 and accordingly a posture of the presser plate 213.

The pivot shafts 213x, 214x are connected through the gears 215g1-215g5. The gears 215g1-215g5 are in mesh with one another. The gear 215g1 is fixed to the pivot shaft 214x, the gear 215g5 is fixed to the pivot shaft 213x, and the gears 215g2-215g4 connect the gear 215g1 and the gear 215g5. When the pivot shaft 214x is driven, the gears 215g1-215g5 are rotated, and rotation of the pivot shaft 214x is transmitted to the pivot shaft 213x, so that the pivot shaft 213x is rotated. While the pivot shaft 214x is driven in the present embodiment, the pivot shaft 213x may be driven. In this case, when the pivot shaft 213x is driven, the gears 215g1-215g5 are rotated, and rotation of the pivot shaft 213x is transmitted to the pivot shaft 214x, so that the pivot shaft 214x is rotated.

In other words, the gears 215g1-215g5 correspond to a transmission member configured to perform: transmission of a pivotal movement of the push-up member 214 about the pivot shaft 214x to a pivotal movement of the basal member 213b about the pivot shaft 213x; and transmission of the pivotal movement of the basal member 213b about the pivot shaft 213x to the pivotal movement of the push-up member 214 about the pivot shaft 214x. The drive force is transmitted by the gears 215g1-215g5, so that the basal member 213b and the push-up member 214 operate in conjunction with each other.

There will be next explained operations of the presser plate 213 and the push-up member 214 in the time period from the fully loaded state (in which the maximal amount of the sheets 100 are loaded on the supply tray 10) to the near empty state (in which the first amount of the sheets 100 are loaded on the supply tray 10, namely, a single sheet is loaded on the supply tray 10 in the present embodiment).

As shown in FIG. 5, the bend angle α is equal to 180° in the fully loaded state.

In the time period from the fully loaded state till before reaching the near empty state, as the amount of the sheets 100 stacked on the supply tray 10 decreases, the push-up member 214 is pivoted by control of the controller 60, as shown in FIG. 6. In this instance, the downstream end 214t of the push-up member 214 moves in a direction directed from the downstream end 213t toward the bend portion 213e along the back surface 213a2 of the distal member 213a. The gears 215g1-215g5 transmit the drive force of the pivot shaft 214x to the pivot shaft 213x, so that the basal member 213b is pivoted about the pivot shaft 213x toward the arm 12. The gear ratio is set such that, in the time period from the fully loaded state till before reaching the near empty state, the distal member 213a is moved upward with its posture kept horizontal and the bend angle α gradually becomes smaller.

Thus, the push-up member 214 and the gears 215g1-215g5 function as an angle adjuster for adjusting the bend angle α defined by the distal member 213a and the basal member 213b.

In the time period from the fully loaded state to the near empty state, the bend angle α is maintained at an obtuse angle, and the distal region 213A is kept opposed to the roller 11.

In the time period from the fully loaded state to the near empty state, a contact angle β, i.e., an angle defined, on the upstream side in the conveyance direction, by the arm 12 and the roller-contacting portion 100a of the sheets 100 on the presser plate 213 which is in contact with the roller 11, is constant. That is, the contact angle 3 is equal to the minimum angle βmin (which is the contact angle in the fully loaded state and is equal to 0° in the present embodiment). Further, the contact angle β is kept less than a maximum angle βmax which is an angle defined, on the upstream side in the conveyance direction, by: (i) the portion of the presser plate 213 corresponding to the basal region 213B in the fully loaded state; and (ii) the arm 12 the roller 11 of which contacts the presser plate 213 which is the presser plate 213 in the fully loaded state and on which it is assumed that the sheets 100 are not loaded in the fully loaded state, i.e., the arm 12 indicated by the long dashed double-short dashed line in FIG. 5.

An angle γ defined by the portion of the presser plate 213 corresponding to the distal region 213A and the separation wall 10w is also kept constant in the time period from the fully loaded state to the near empty state.

As described above, the present embodiment offers the same advantages as those offered by the first embodiment according to the same configuration as employed in the first embodiment. The second embodiment further offers the following advantages.

The angle adjuster includes the gears 215g1-215g5 that permit the basal member 213b and the push-up member 214 to operate in conjunction with each other. With this configuration, it is not necessary to individually drive the basal member 213b and the push-up member 214, resulting in a decrease in the number of drive sources.

Third Embodiment

Referring next to FIGS. 8-10, there will be explained a printer according to a third embodiment. The printer of the third embodiment differs from the printer of the first embodiment in structures of the presser plate, the push-up member, and the supply tray, and other structures are the same as in the first embodiment.

A supply tray 310 has: a protruding portion 310p (as one example of “limiter”) that protrudes outward from an upper end of the separation wall 310w; and a through-hole 310q formed in the separation wall 310w.

The supply tray 310 pivotably supports: a presser plate 313 for pressing the sheets 100 stored in the supply tray 310 toward the roller 11; and a push-up member 314 for pushing up the presser plate 313 from below so as to pivot the presser plate 313. A pivot shaft 313x of the presser plate 313 and a pivot shaft 314x of the push-up member 314 are parallel to the rotation shaft 11x and are rotatably supported by the supply tray 310. The presser plate 313 is pivotable about the pivot shaft 313x while its downstream end 313t is located downstream of the pivot shaft 313x in the conveyance direction. The push-up member 314 is pivotable about the pivot shaft 314x while its downstream end 314t is located downstream of the pivot shaft 314x in the conveyance direction.

The presser plate 313 includes, between the downstream and 313t and the pivot shaft 313x, a bend portion 313c which is bendable. The presser plate 313 includes a distal member 313a shaped like a plate and having the downstream end 313t and a basal member 313b shaped like a plate and at which the pivot shaft 313x is provided. A boundary between the distal member 313a and the basal member 313b corresponds to the bend portion 313c.

Front surfaces 313a1, 313b1 of the distal member 313a and the basal member 313b which face the roller 11 respectively constitute a distal region 313A and a basal region 313B. The distal region 313A is a region ranging from the downstream end 313t to the bend portion 313c. The basal region 313B is a region ranging from the bend portion 313c to the pivot shaft 313x.

A rotation shaft 313ax is provided at an upstream end of the distal member 313a which is located opposite to the downstream and 313t in the conveyance direction and at which the bend portion 313c is provided. The rotation shaft 313ax is rotatably supported by a downstream end of a basal member 313b which is located opposite to an upstream end of the basal member 313b in the conveyance direction at which the pivot shaft 313x is provided. That is, the distal member 313a and the basal member 313b are connected to each other through the bend portion 313c such that a bend angle α is changeable. In the present embodiment, the bend angle α is an angle defined by a portion of the presser plate 313 corresponding to the distal region 313A and a portion of the presser plate 313 corresponding to the basal region 313B, on one side of the presser plate 313 that is farther from the arm 12.

The rotation shaft 313ax is provided with a spring 313s (as one example of “biasing member”). The spring 313s biases the distal member 313a and the basal member 313b in a direction to increase the bend angle α. A stopper (not shown) is disposed at the bend portion 313c of the presser plate 313 for preventing the bend angle α from becoming larger than 180°.

The push-up member 314 is configured to pivot about the pivot shaft 314x by control of the controller 60 while its downstream end 314t is held in contact with a back surface 313b2 of the basal member 313b (which is opposite to the front surface 313b1 thereof), so as to cause the basal member 313b to be pivoted about the pivot shaft 313x. The controller 60 is configured to receive a signal from the sensor 70 and to drive the pivot shaft 314x in accordance with the amount of the sheets 100 stacked on the supply tray 310, thereby controlling a postured of the push-up member 314 and accordingly a posture of the presser plate 313.

There will be next explained operations of the presser plate 313 and the push-up member 314 in the time period from the fully loaded state (in which the maximal amount of the sheets 100 are loaded on the supply tray 310) to the near empty state (in which the first amount of the sheets 100 are loaded on the supply tray 310, namely, a single sheet is loaded on the supply tray 10 in the present embodiment).

As shown in FIG. 8, the bend angle α is equal to 180° in the fully loaded state. In this instance, the distal member 313a is supported by a lower surface that defines the through-hole 310q formed in the separation wall 310w.

In the time period from the fully loaded state till before reaching the near empty state, as the amount of the sheets 100 stacked on the supply tray 310 decreases, the push-up member 314 is pivoted by control of the controller 60, as shown in FIG. 9. In this instance, the downstream end 314t of the push-up member 314 moves in a direction directed from the bend portion 313c toward the pivot shaft 313x along the back surface 313b2 of the basal member 313b. The push-up member 314 pushes up the downstream end of the basal member 313b, whereby the basal member 313b is pivoted about the pivot shaft 313x toward the arm 12.

In a process in which the state of the supply tray 10 changes from the fully loaded state to the near empty state, the distal member 313a is moved upward with its posture kept parallel to the basal member 313b until the downstream end 313t of the presser plate 313 comes into contact with the protruding portion 310p. The bend angle α is constant until the downstream end 313t of the presser plate 313 comes into contact with the protruding portion 310p. In a time period from a time point when the downstream end 313t comes into contact with the protruding portion 310p till before reaching the near empty state, the basal member 313b is pushed up by the push-up member 314 in a state in which the downstream end 313t of the distal member 313a is inhibited from moving upward by the protruding portion 310p, whereby the bend angle α is gradually decreased against the biasing force of the spring 313s, as shown in FIG. 10.

Thus, the spring 313s, the push-up member 314, and the protruding portion 310p function as an angle adjuster for adjusting the bend angle α defined by the distal member 313a and the basal member 313b.

In the time period from the fully loaded state to the near empty state, the bend angle α is maintained at an obtuse angle, and the distal region 313A is kept opposed to the roller 11.

In the time period from the fully loaded state to the near empty state, a contact angle β, i.e., an angle defined, on the upstream side in the conveyance direction, by the arm 12 and the roller-contacting portion 100a of the sheets 100 on the presser plate 313 which is in contact with the roller 11, is kept less than a maximum angle βmax but is not constant. Here the maximum angle βmax is an angle defined, on the upstream side in the conveyance direction, by (i) the portion of the presser plate 313 corresponding to the basal region 313B in the fully loaded state and (ii) the arm 12 the roller 11 of which contacts the presser plate 313 which is the presser plate 313 in the fully loaded state and on which it is assumed that the sheets 100 are not loaded in the fully loaded state, i.e., the arm 12 indicated by the long dashed double-short dashed line in FIG. 8. In the present embodiment, the contact angle β is gradually increased from the fully loaded state till the time point when the downstream end 313t comes into contact with the protruding portion 310p and becomes larger than the minimum angle βmin (which is the contact angle in the fully loaded state and is equal to 0° in the present embodiment). However, the contact angle is gradually decreased in the time period from the time point when the downstream end portion 313t comes into contact with the protruding portion 310p till before reaching the near empty state, and becomes equal to the minimum angle βmin in the near empty state.

In the present embodiment, an angle γ defined by the portion of the presser plate 313 corresponding to the distal region 313A and the separation wall 10w is not constant, either, from the fully loaded state to the near empty state. The angle γ is gradually increased from the fully loaded state till the time point when the downstream end 313t comes into contact with the protruding portion 310p, and is gradually decreased in the time period from the time point when the downstream end 313t comes into contact with the protruding portion 310p till before reaching the near empty state. The angle γ in the near empty state is equal to the angle γ in the fully loaded state.

As described above, the present embodiment offers the same advantages as those offered by the first embodiment according to the same configuration as employed in the first embodiment. The third embodiment further offers the following advantages.

The angle adjuster includes the spring 313s provided at the bend portion 313c, the push-up member 314 configured to pivot the basal member 313b about the pivot shaft 313x, and the protruding portion 310p configured to limit the movement of the downstream end 313t With this configuration, the bend angle α is effectively adjusted by a cooperative operation of the spring 313s, the push-up member 314, and the protruding portion 310p.

While the embodiments of the disclosure have been described above, it is to be understood that the disclosure is not limited to the details of the illustrated embodiments, but may be embodied with other various changes and modifications, which may occur to those skilled in the art, without departing from the scope of the disclosure.

The presser plate does not necessarily have to support the entirety of the sheets, but may support a part of the sheets (including a portion facing the roller). In this case, other part of the sheets may be supported directly by the container.

The contact angle is an angle defined, on the upstream side in the conveyance direction, by a plane that includes the arm and a plane along the roller-contacting portion of the sheets on the presser plate which is in contact with the roller. The contact angle is equal to 0° when these planes are in parallel with each other as shown in FIGS. 2-8 and 10. The contact angle may be a positive value (FIG. 9) or a negative value.

The distal region need not necessarily extend in the horizontal direction in the near empty state.

In the second embodiment, the gears 215g1-215g5 (the transmission member) perform both of: transmission of the pivotal movement of the push-up member 214 about the pivot shaft 214x to the pivotal movement of the basal member 213b about the pivot shaft 213x; and transmission of the pivotal movement of the basal, member 213b about the pivot shaft 213x to the pivotal movement of the push-up member 214 about the pivot shaft 214x. The transmission member may perform only one of the transmissions.

In the second embodiment, the transmission member may be omitted, and the basal member and the push-up member may be individually driven. In this case, it is preferable to individually control driving of the basal member and driving of the push-up member such that, in the time period from the fully loaded state to the near empty state, the distal member 213a moves upward with its posture kept horizontal and the bend angle α is gradually decreased.

In place of the sensor 70 for detecting the amount of the sheets 100 loaded on the supply tray, a sensor for detecting an angle of the arm 12 may be used, for instance. In this case, the controller 60 may be configured to receive a signal from the sensor and to control the postures of the push-up member and the presser plate such that the angle of the arm 12 is kept constant, namely, the arm 12 is kept horizontal, for instance.

The push-up member may be omitted, and the rotation shaft of the basal member provided at the distal member and the presser-plate pivot shaft provided at the basal member may be coupled to gears. In this case, when the presser-plate pivot shaft is driven and the basal member pivots about the presser-plate pivot shaft, the drive force of the presser-plate pivot shaft is transmitted to the rotation shaft by the gears, so that the distal member pivots about the rotation shaft.

It is not necessarily required that the presser plate is constituted by a plurality of members connected to each other and the bend angle is adjustable. The presser plate may be constituted by a single member, and the bend angle may be kept constant.

In the illustrated embodiments, the arm is supported by the housing of the sheet conveying apparatus. The arm may be supported by the container.

The recording portion may be an ink-jet type, a thermal type, or a laser type. The sheet conveying apparatus according to the disclosure is not limited to the printer, but may be a facsimile, a copying machine, or a multi-function peripheral (MFP), for instance. The sheet conveying apparatus does not necessarily have to have the recording portion. The sheet is not limited to paper but may be a cloth, for instance.