Sheet separation member and sheet supply device

A sheet separation member for use in a sheet supply device including a sheet feed roller that feeds stacked sheets. The sheet separation member includes a body portion including a plurality of protrusion portions that engages with leading edges of the stacked sheets in a sheet feeding direction, and a plurality of arm portions that supports the protrusion portions in positions where the protrusion portions are engaged with the leading edges of the sheets, and a plurality of plate spring portions integrally formed with the body portion to support the body portion in a predetermined region of the sheet supply device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sheet separation member cooperating with a sheet feed roller to separate and feed sheets of paper one by one in an image forming apparatus such as a printer, a copying machine or a facsimile, and a sheet supply device including the sheet separation member.

2. Description of the Related Art

As this type of device, for example, as shown inFIGS. 17A and 17B, there is heretofore known a device configured to have a sheet separation portion92disposed to come into contact with lower end surfaces of sheets of paper90so that only an uppermost one of the sheets of paper90is separated by a frictional force between the sheet separation portion92and the lower end surfaces of the sheets of paper90(e.g. see JP-A-2002-137838).

In the conventional device, a separation portion supporting portion93is formed to support the sheet separation portion92by means of two support portions93aand93beach having a protrusive upper section in a longitudinal direction. Incidentally, a gap93cis formed between the sheet separation portion92and the separation portion supporting portion93so as to give flexibility to the sheet separation portion92.

The sheet separation portion92is made of a rubber material such as polyurethane. The sheet separation portion92has a convex end surface substantially fit to the shape of an end surface of a holder portion91disposed on the upper portion of the sheet separation portion92. As shown inFIGS. 18A-18C, a protrusive portion92ais formed in the sheet separation portion92. The protrusive portion92ais configured to always protrude from a long hole of the holder91made of metal. The long hole is formed so as to extend in a sheet stacking direction.

The height of the protrusive portion92ais set so that the protrusive portion92aprotrudes from the long hole of the holder portion91by a predetermined amount. The lower edges of the sheets of paper90stored in a sheet storage portion are brought into contact with the upper surface of the protrusive portion92a.

Fine irregularities92bare formed in the upper surface of the protrusive portion92a. The fine irregularities92bact to increase the frictional force generated between the sheet separation portion92and the lower edges of the sheets of paper90.

The conventional device is configured in this manner so that the sheets of paper90are separated one by one by the frictional force of the rubber material and the action of the fine irregularities92bto increase the frictional force and in accordance with the balance with a sheet feed force of the sheet feed roller.

SUMMARY OF THE INVENTION

The aforementioned sheet supply device has a structure in which a load from the sheets of paper is received by the whole of the protrusive portion of the sheet separation portion. For this reason, the load applied to the protrusive portion varies largely according to the number of sheets of paper giving a load to the sheet separation portion. There is therefore a problem that setting of the flexibility of the sheet separation portion and design and manufacturing of the shape of each of the fine irregularities formed in the protrusive portion become complicated.

The protrusion amount of the protrusive portion92aof the sheet separation portion92from the holder portion91is set in accordance with an elastic force of the sheet separation portion92made of a rubber material. Accordingly, there is another problem that the protrusion amount changes momentarily in accordance with a temperature condition, a humidity condition, and so on, so as to be very unstable.

Further, because the conventional sheet supply device is constituted by three members of the holder portion91, the sheet separation member92and the separation portion supporting portion93, the number of parts is large to thereby result in high cost.

In consideration of such circumstances, one of objects of the invention is to provide a sheet separation member which does not require complicated design and manufacturing and is small in the number of parts, and which can prevent multiple sheet feed (i.e. which can prevent sheets of paper from being fed collectively) so that the sheets of paper can be fed one by one surely, and a sheet supply device including the sheet separation member.

According to a first aspect of the invention, there is provided a sheet separation member for use in a sheet supply device including a sheet feed roller that feeds stacked sheets, the sheet separation member including: a body portion including a plurality of protrusion portions that engages with leading edges of the stacked sheets in a sheet feeding direction, and a plurality of arm portions that support the protrusion portions in positions where the protrusion portions are engaged with the leading edges of the sheets; and a plurality of plate spring portions integrally formed with the body portion to support the body portion in a predetermined region of the sheet supply device.

According to a second aspect of the invention, there is provided a sheet supply device including: a sheet storage portion that stores sheets; a sheet feed roller that feeds the sheets stored in the sheet storage portion to a predetermined conveyance path; an inclined surface located in the predetermined conveyance path so as to be inclined at an obtuse angle with respect to the sheets stored in the sheet storage portion, the inclined surface including a long hole being formed thereon so as to extend in a sheet conveyance direction; and a sheet separation member including: a body portion including a plurality of protrusion portions that engages with leading edges of the stacked sheets in a sheet feeding direction, and a plurality of arm portions that support the protrusion portions in positions where the protrusion portions are engaged with the leading edges of the sheets; and a plurality of plate spring portions integrally formed with the body portion to support the body portion in a predetermined region of the sheet supply device, wherein the sheet separation member is mounted in the sheet supply device so that the protrusion portions protrudes from the inclined surface through the long hole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the invention will be described below with reference to the drawings.

Incidentally, the embodiment shows the case where the invention is applied to a sheet supply device of a printer constituting a so-called multifunction machine.

As shown inFIGS. 1 and 2, in the multifunction machine where a scanner2is provided on an upper portion of a casing1, the printer according to the embodiment is provided for forming an image on a sheet A. The printer includes a sheet supply device30in a lower portion in the casing1.

A metal frame5shaped like a box is disposed in the rear in the casing1and above the sheet supply device30. The frame5is substantially shaped like a rectangular parallelepiped long in a left-right direction. The frame5is fixed while extending in the casing1.

A recording portion7is disposed in an upper portion of the inside of the frame5. A conveyance path5afor leading a sheet A to the recording portion7from the rear of the sheet supply device30is formed in the rear of the frame5. Specifically, the recording portion7is an inkjet type recording device. The recording portion7has introduction rollers7alocated in a place adjacent to an exit of the conveyance path5a, and ejection rollers7blocated in a place where the sheet A having an image recorded thereon is ejected. Because the inkjet type recording device configured thus is known, description thereof will be omitted here.

An ejection portion for ejecting the sheet A from the recording portion7is provided in front of the frame5in the casing1. The sheet A ejected to the ejection portion is stacked on a tray3bof a sheet supply cassette3in the sheet supply device30.

FIG. 3is a perspective view of the sheet supply device according to the embodiment.

The sheet supply device30exhibits an external appearance as shown inFIG. 3. The sheet supply cassette3in the sheet supply device30is inserted in the casing1so that the sheet supply cassette3can be pulled in and out freely in a front-rear direction through an opening portion4. A sheet storage portion3afor storing stacked sheets of paper A is provided in the sheet supply cassette3. When the sheet supply cassette3is inserted into the casing1, the sheet A in the sheet storage portion3ais disposed in the rear in the casing1. The tray3bfor accepting a sheet A having an image recorded thereon, as will be described later, is formed in front of the sheet supply cassette3.

The sheet supply device30includes a pendulum type sheet feed roller8for feeding a sheet A in the sheet storage portion3ato the recording portion7. The sheet feed roller8is rotatably held in an end portion of an arm10which is a long support member pivoted by a driving shaft9. Motive power is transmitted from the driving shaft9to the sheet feed roller8through gears serving as transmission rotators to thereby rotate the sheet feed roller8.

The driving shaft9is pivoted in the frame5so as to extend in the left-right direction. A driving gear11is fixed to an end of the driving shaft9. An output shaft of a driving source (not shown) such as a motor is dynamically connected to the driving gear11. As a result, when the driving source is activated to rotate the driving shaft9, the rotation of the driving shaft9is transmitted to the sheet feed roller8through the gears serving as transmission rotators. The sheet feed roller8comes into contact with the uppermost sheet of paper A in the sheet storage portion3ato thereby feed the sheet A to the recording portion7.

An inclined surface20is formed in the sheet supply device30according to the embodiment so as to be inclined at an obtuse angle φ with respect to the sheet A stored in the sheet storage portion3a(seeFIG. 2). The sheet A fed by the sheet feed roller8is conveyed to the conveyance path5awhile its leading edge is brought into contact with the inclined surface20.

FIG. 4is a front view of the inclined surface20of the sheet supply device30.FIG. 5is a sectional view taken along the line V-V, of the inclined surface20shown inFIG. 4.FIG. 6is a sectional view taken along the line VI-VI, of the inclined surface20shown inFIG. 4.FIG. 7is a sectional view taken along the line VII-VII, of the inclined surface20shown inFIG. 4.

FIGS. 8A and 8Bare perspective views of a sheet separation member50according to the invention.FIGS. 9A and 9Bare perspective views of another example of the sheet separation member50according to the invention (the sheet separation member shown inFIGS. 8A and 8Band the sheet separation member shown inFIGS. 9A and 9Bare different from each other in directions of plate spring portions54).

First, the sheet separation member50according to the invention will be described.

As is apparent fromFIGS. 8A and 8BorFIGS. 9A and 9B, the sheet separation member50includes a body portion53, and plate spring portions54. The body portion53has a plurality of protrusion portions51, and a plurality of arm portions52. The protrusion portions51engage with leading edges of stacked sheets of paper in the sheet feeding direction. The arm portions52support the protrusion portions51in positions where the protrusion portions51can be engaged with the leading edges of the sheets of paper. The plate spring portions54are formed so as to be integrated with the body portion53. The plate spring portions54are provided for supporting the body portion53in a predetermined region of the sheet supply device30.

When the protrusion portions51are engaged with the leading edges (in the sheet feeding direction) of the sheets of paper to be conveyed to the conveyance path by the sheet feed roller so that the leading edges of the sheets are caught by the protrusion portions, the stacked sheets come apart from one another. Finally, the protrusion portions51perform a function of separating a sheet of paper to be conveyed to the recording portion. Accordingly, the shape of each of the protrusion portions51is not limited particularly as long as the shape allows this function to be performed. The size of each of the protrusion portions51is also not limited particularly but may be decided suitably.

Although seven protrusion portions51are formed in the sheet separation member50according to the invention as shown inFIGS. 8A and 8BorFIGS. 9A and 9B, the number of protrusion portions is not limited particularly in the invention but may be decided arbitrarily. If the number of protrusion portions is too small, it is however impossible to keep the sheets of paper sufficiently apart from one another and it is impossible to separate a sheet of paper surely from the stack. Accordingly, it is preferable that the number of protrusion portions is three or more.

The arm portions52have a function of supporting the protrusion portions51so that the protrusion portions51can always perform the aforementioned function, that is, the protrusion portions51can be engaged with the leading edges of the sheet Accordingly, the shape of each of the arm portions52is also not limited particularly as long as the shape allows this function to be performed. For example, in the sheet separation member50according to the invention as shown inFIGS. 8A and 8BorFIGS. 9A and 9B, each of the arm portions52supports the corresponding protrusion portion51nearly at the center of each of the arm portions52.

The shape of each of the arm portions52is not limited to the examples shown inFIGS. 8A and 8Bor inFIGS. 9A and 9B. For example, each arm portion52may be provided so as to support a plurality of protrusion portions or each arm portion52may be provided so as to support a plurality of protrusion portions at its ends. However, when the arm portions have one-to-one correspondence with the protrusion portions as shown inFIGS. 8A and 8BorFIGS. 9A and 9Bso that the protrusion portions can be supported by the arm portions respectively, a load applied from the sheets of paper can be controlled in accordance with the protrusion portions. As a result, the sheets of paper can be separated stably without necessity of complicated design and manufacturing of the protrusion portions. Accordingly, multiple sheet feed can be prevented, that is, sheets of paper can be prevented from being fed collectively. From this point of view, it is preferable that some elasticity is given to each arm portion52. It is also preferable that the shape of each arm portion52is decided in consideration of this point.

Although the arm portions52shown in the figures are formed to support the protrusion portions51from opposite sides, that is, from left and right sides, for example, in the sheet separation member50according to the embodiment as shown inFIGS. 8A and 8B, each of the arm portions52is not particularly limited to such a shape. For example, the arm portions52may be formed to support a plurality of protrusion portions51from either of the opposite sides alternately.

The plate spring portions54perform a function of supporting the body portion53(having the protrusion portions51, and the arm portions52) in a predetermined region (specifically, a sheet separation member storing space22which will be described later) of the sheet supply device30. At the same time, the plate spring portions54perform a function of giving elasticity to the whole of the sheet separation member50to relax the pressure given from the sheets of paper engaged with the protrusion portions51to thereby make smooth separation possible. The sheet separation member50according to the invention has an important characteristic in that the plate spring portions54are formed so as to be integrated with the protrusion portions51and the arm portions52. In this manner, the number of parts can be reduced, so that cost can be reduced.

The shape of each of the plate spring portions54in the invention is not limited particularly, that is, any shape can be used as the shape of each plate spring portion54as long as the shape allows the aforementioned functions to be performed. It is preferable that the plate spring portions54are formed to protrude obliquely from side edges55of the body portion53which are parallel with the sheet feeding direction, as shown inFIGS. 8A and 8BorFIGS. 9A and 9B. When the plate spring portions54are formed in this manner to protrude obliquely from the side edges55of the body portion53substantially exhibiting a rectangular shape, the whole of the body portion can be supported uniformly by the plate spring portions54. In addition, when the sheet separation member50according to the invention is manufactured by pressing, the material can be used efficiently (cut-off portions due to the pressing can be reduced). Incidentally, in the invention, an angle at which each plate spring portion54protrudes from a corresponding side edge55of the body portion53is not limited particularly. The plate spring portions54may be formed obliquely to face forward in the direction (see the black arrow inFIG. 8A) of insertion of the sheet separation member50as shown inFIGS. 8A and 8B, or may be conversely formed obliquely to face rearward in the insertion direction of the sheet separation member50as shown inFIGS. 9A and 9B. In other words, the plate spring portions54may be formed obliquely to protrude from the body portion upward or downward in a sheet stacking direction.

The material of the sheet separation member50according to the invention is not limited particularly. Preferably, the sheet separation member50is made of metal. Specifically, a stainless steel plate, an aluminum plate, a copper plate or the like is preferably used. A method for manufacturing the sheet separation member50according to the invention is not particularly limited. Any method known in the related art can be used. For example, the sheet separation member50can be manufactured by pressing a stainless steel plate.

As shown inFIGS. 4 to 7, a long hole21is formed in the inclined surface20of the sheet supply device30according to the embodiment so as to extend in the conveyance direction of the sheet A (from the lower to the upper inFIG. 4). The storage space22for placing the sheet separation member50is provided on a rear side of the surface where the long hole21is formed, so that the protrusion portions51of the sheet separation member50according to the embodiment protrude toward a front side of the inclined surface20.

Incidentally, when the storage space22is provided thus in the inclined surface20of the sheet supply device30, it is possible to reduce the number of parts to thereby achieve cost reduction.

As is apparent fromFIGS. 6 and 7, the storage space22is shaped like a box. The sheet separation member50has an external shape allowed to be stored in the storage space22. The sheet separation member50is fixed in the storage space22through a fixation member60which is formed into a box shape allowed to receive the body portion53of the sheet separation member50inside.

That is, the fixation member60is formed so that the plate springs54protruding left and right from the body portion53of the sheet separation member50are supported by end surfaces of left and right side walls62opposite to each other. As a result, the fixation member60fixes the body portion53of the sheet separation member50in the storage space22while displaceably supporting the body portion53in the storage space22.

Incidentally, the sheet separation member50is received in the storage space22in such a manner that the inclination angle of each of the protrusion portions51of the sheet separation member50to the inclined surface20becomes an obtuse angle in the conveyance direction of the sheet A and therefore the protrusion portions51do not disturb conveyance of the sheet A when the protrusion portions51protrude from the long hole21of the inclined surface20. The amount of protrusion of each of the protrusion portions51from the inclined surface20when the sheet separation member50is stored thus in the storage space22is preferably selected to be in a range of from about 0.1 mm to about 0.4 mm.

As described above, in the sheet supply device30according to the embodiment, the long hole21is formed in the conveyance direction of the sheet A in the inclined surface20with which the leading edges of the sheets A are brought into contact at the time of sheet feed so that one of the sheet A is led to the conveyance path5aby the protrusion portions51of the sheet separation member50protruded from the long hole21. With this configuration, separation loads applied to the leading edges of the sheets A from the protrusion portions51at the time of sheet feed can be prevented from varying largely according to the number of sheets A stacked in the sheet storage portion3a. When the separation loads are set to be equal to one another for the respective protrusion portions51, the sheet A may not be fed well due to variation in the sheet A conveyance force of the sheet feed roller8.

That is, as shown inFIG. 10A, the sheet feed roller8according to the embodiment is a so-called pendulum type sheet feed roller which is provided at one end of the arm10while the other end of the arm10is pivoted by the driving shaft9. Accordingly, when an angle θ formed between the plane of the sheet A and a line segment between a contact point between the sheet feed roller8and the sheet A and the driving shaft9changes in accordance with a change in the number of stacked sheets of paper A, a contact force applied to the sheet A from the sheet feed roller8changes.

The contact force increases as the number of stacked sheets of paper decreases from the maximum (the top position in the sheet stacking range shown inFIG. 10A) (in other words, as the angle θ increases). Accordingly, the conveyance force of the sheet A with rotation of the sheet feed roller8decreases as the number of stacked sheets of paper A increases (in other words, as the angle θ decreases) as shown inFIG. 10B.

As shown inFIGS. 2 and 3, an anti-slip member3cconstituted by a cork, etc. is provided in an opposite surface of the sheet storage portion3ato the sheet feed roller8in the sheet supply device30so that multiple sheets of paper can be prevented from being fed collectively when the number of residual sheets of paper A becomes small.

Therefore, the sheet A conveyance force of the sheet feed roller8decreases also when the number of sheets of paper A stacked in the sheet storage portion3adecreases (i.e. when the angle θ is near the maximum angle) as shown inFIG. 10B.

Accordingly, in the sheet supply device30according to the embodiment, the separation loads applied to the leading edges of the sheets A from the protrusion portions51constituting the sheet separation member50are preferably set in accordance with characteristic of the sheet A conveyance force of the sheet feed roller8shown inFIG. 10B. That is, the separation load for each protrusion portion51constituting the sheet separation member50is preferably set in accordance with the number of stacked sheets of paper A in the sheet storage portion3aso that the separation load decreases as the number of the stacked sheets of paper A increases and as the number of stacked sheets of paper residual in the sheet storage portion3adecreases.

To this end, the spring constants of the arm portions52supporting the protrusion portions51respectively in the sheet separation member50may be set individually by adjusting the widths, plate thicknesses, or the like of the arm portions52. Setting the spring constants of the arm portions52individually is however very laborious.

In this embodiment, a sheet separation member50shown inFIG. 11Aand obtained by changing the basic configuration shown inFIGS. 8A and 8Bis practically used as the sheet separation member50. The sheet separation member50is fixed in a storage space22through a fixation member60in which the whole regions of side walls62are set to have a uniform height, as shown inFIG. 11B.

That is, as shown inFIG. 11A, when two pairs of plate springs54(two for left and two for right, that is, four in total) located on a sheet-A-stacking-direction upper side and one pair of left and right plate springs54located on a sheet-A-stacking-direction lower side are eliminated from plate springs54protruded at substantially equal intervals from left and right side edges55of a body portion53for supporting the body portion53in the sheet separation member50, arrangement density of the plate springs54is reduced on the sheet-A-stacking-direction upper and lower sides so that a separation load of each of protrusion portions51located on the sheet-A-stacking-direction upper and lower sides is smaller than a separation load of any protrusion portion51located in a sheet-A-stacking-direction center portion.

As a result, in the sheet supply device30according to the embodiment, the separation loads applied to the leading edges of the sheets A from the protrusion portions51constituting the sheet separation member50can be set very easily in accordance with the sheet A conveyance force of the sheet feed roller8, so that the sheets A stacked in the sheet storage portion3acan be fed one by one surely without causing no feed or multiple sheet feed.

Because the sheet separation member50according to the embodiment is formed by pressing a metal plate, the respective parts in the sheet separation member50are formed integrally. With this configuration, the sheet separation member50can be achieved easily without necessity of complicated design and manufacturing of the protrusion portions51. Moreover, it is possible to reduce the total number of parts in the sheet supply device30to thereby improve manufacturing efficiency and it is possible to reduce the cost of the sheet separation member50.

At the time of sheet feed, sheet powder may be generated due to friction between the sheet A to be fed and the protrusion portions51. Because most of the sheet powder falls down through gaps between the arm portions52, it is possible to reduce the influence of the generated sheet powder on sheet separation.

Although the embodiment of the invention has been described above, the invention is not limited to the aforementioned embodiment but may use various modes without departing from the gist of the invention.

For example, the embodiment has been described on the case where the sheet separation member50is produced by eliminating two pairs of plate springs54(two for left and two for right, that is, four in total) located on the sheet-A-stacking-direction upper side and eliminating one pair of left and right plate springs54located on the sheet-A-stacking-direction lower side from the spring plates54protruded from the left and right side edges55of the body portion53at substantially equal intervals for supporting the body portion53. Alternatively, the separation load of the protrusion portion51disposed on the sheet-A-stacking-direction upper or lower side may be reduced in accordance with lowering of the sheet A conveyance force of the sheet feed roller8by a method of eliminating one pair of left and right plate springs54located on the sheet-A-stacking-direction upper side as shown inFIG. 12A, by a method of eliminating two pair of left and right plate springs54located on the sheet-A-stacking-direction upper and lower sides as shown inFIG. 12B, or by a method of eliminating one pair of left and right plate springs54located on the sheet-A-stacking-direction lower side as shown inFIG. 12C. Thus, it is possible to prevent a failure in sheet feed caused by a change in the sheet A conveyance force of the sheet feed roller8.

The sheet separation members50shown inFIGS. 11A,11B and12A-12C are described on the assumption that the spring plates54are protruded from the left and right side edges55of the body portion53at substantially equal intervals. By changing a protrusion interval, arrangement density of the plate springs54on the sheet-A-stacking-direction upper or lower side can be reduced so that the separation load of the protrusion portion51disposed on the sheet-A-stacking-direction upper or lower side may be made smaller than the separation load of any protrusion portion51in the sheet-A-stacking-direction center portion.

Alternatively, as shown inFIGS. 13A and 13B, in a sheet separation member50, plate springs54are protruded at substantially equal intervals from left and right side edges55of a body portion53and the width of each of plate springs54alocated in sheet-A-stacking-direction upper and lower sides is made smaller than the width of any plate spring54in the sheet-A-stacking-direction center portion so as to reduce the spring constant of the plate spring54a.

On the other hand, in order to make a separation load of a protrusion portion51located on the sheet-A-stacking-direction upper or lower side smaller than a separation load of any protrusion portion51in a sheet-A-stacking-direction center portion among protrusion portions51constituting the sheet separation member50, the following method may be used by way of example without necessity of adjustment of the spring constants on the sheet separation member50side. That is, plate springs54are protruded at substantially equal intervals from left and right side edges55of a body portion53in a sheet separation member50as shown inFIG. 14Aand parts (specifically, on the sheet-A-stacking-direction lower or upper sides) of a pair of left and right side walls62of a fixation member60for supporting the plate springs54of the sheet separation member50are cut off as shown inFIG. 14B.

That is, when the opposite ends of each of the side walls62of the fixation member60are cut off in this manner, the plate springs54located on the sheet-A-stacking-direction upper and lower sides among the plate springs54constituting the sheet separation member50are not supported by the fixation member60so that the spring constants of the plate springs54on the sheet-A-stacking-direction upper and lower sides are reduced. Accordingly, it is possible to obtain the same advantage as that in the embodiment.

Incidentally, for the shape (in other words, height) of each side wall62of the fixation member60to be adjusted thus, the height of the side wall62may be changed stepwise or continuously, as shown inFIGS. 15A and 15BorFIGS. 16A and 16B, in accordance with a change of the conveyance force of the sheet feed roller8shown inFIG. 10B. Accordingly, it is possible to improve characteristic of separation and feed of the sheet A.

On the other hand, although the embodiment has been described on the case where the invention is applied to a printer of a multifunction machine, the invention can be applied to any apparatus such as a copying machine or a facsimile in the same manner as the embodiment and obtain the same advantage as that in the embodiment, as long as the apparatus includes a sheet supply device for separating and feeding sheets of paper stored in a stack state one by one.

The embodiment has been described about the sheet supply device where sheets of paper A on the stacking-direction upper side (i.e. vertical-direction upper side) are separated and fed one by one to the printer while the sheets A are stacked substantially vertically with the sheet plane being set horizontally in the sheet supply cassette3disposed in the lower portion of the printer. For example, the invention can be applied, in the same manner as the embodiment to obtain the same advantage as that in the embodiment, to a sheet supply device in which sheets A on a stacking-direction upper side (i.e. obliquely upper side) are separated and fed one by one to the printer while the sheets A are stacked obliquely with the sheet plane being set obliquely in a sheet storage portion disposed in the rear of a printer.

In this specification, the sheet supply device is described as a device for supplying “sheets of paper” in an apparatus and the sheet separation member is described as a member for separating the “sheets of paper” one by one. The “sheets of paper” are not limited to paper but may include plastic films (so-called resin sheets) such as OHP films, laminated sheets made of resin and paper, and various kinds of sheets. The invention can be applied to any sheet supply device for supplying the resin sheets or laminated sheets other than paper and to any sheet separation member in the same manner as the embodiment and obtain the same advantage as that in the embodiment.

According to the embodiment, in the sheet separation member for use in the sheet supply device including the sheet feed roller for feeding stacked sheets, the protrusion portions are supported by the arm portions. With this configuration, a load applied to the respective protrusion portions is divided and supported by the arm portions so that the load from the sheets can be controlled in accordance with each of the protrusion portions supported by the arm portions. As a result, stable sheet separation can be attained without necessity of complicated design and manufacturing of the protrusion portions, and multiple sheet feed can be prevented (i.e. a plurality of sheets can be prevented from being fed collectively).

Sheet powder may be generated due to friction between the sheets to be fed and the protrusion portions at the time of sheet feed. Most of the sheet powder falls down through gaps between the arm portions, so that the influence of the generated sheet powder on sheet separation can be reduced.

In the sheet separation member according to the embodiment, the body portion constituted by the protrusion portions and the arm portions is formed so as to be integrated with the plate spring portions for supporting the body portion in a predetermine region of the sheet supply device. With this configuration, the “sheet separation portion and separation portion supporting portion” included in the sheet separation member according to the related art are formed by one member in the sheet separation member according to the invention. As a result, it is possible to reduce the total number of parts, improve manufacturing efficiency and reduce cost.

According to the embodiment, the plate spring portions are formed to protrude obliquely from the side edges of the body portion, the side edges being parallel to the sheet feeding direction. With this configuration, the whole of the body portion can be pressed against the predetermined region of the sheet supply device by a uniform force.

According to the embodiment, the sheet separation member is made of metal (i.e. the protrusion portions, the arm portions and the plate spring portions are all made of metal). With this configuration, unlike the sheet separation portion made of resin according to the related art, the shape of each of the protrusion portions is unlikely to deform due to a temperature condition, a humidity condition etc., and the sheet separation member is unlikely to wear even after used for a long term. Thus, the sheet separation member can be given durability.

According to the embodiment, the sheet supply device includes: a sheet storage portion for storing a plurality of sheets; a sheet feed roller for feeding the sheets stored in the sheet storage portion to a predetermined conveyance path; and an inclined surface located in the predetermined conveyance path and inclined at an obtuse angle with respect to the sheets stored in the sheet storage portion; wherein a long hole is formed in the inclined surface so as to extend in a sheet conveyance direction; and the sheet separation member is mounted in the sheet supply device so that protrusion portions of the sheet separation member pass through the long hole and protrude from the inclined surface. With this configuration, the sheet separation member according to the invention having various advantages as described above can be used in the sheet supply device and the “holder portion” included in the sheet separation member according to the related art is formed so as to be integrated with the inclined surface of the sheet supply device. Accordingly, it is not necessary to manufacture the holder portion individually and separately. As a result, it is possible to reduce the total number of parts.

According to the embodiment, there is provided a sheet separation member used in a sheet supply device for separating and feeding stacked sheets of paper one by one by rotation of a pendulum type sheet feed roller, the sheet supply device including the sheet feed roller brought into contact with a sheet plane by an urging force received from a long support member having one end pivoted and the other end attached to the sheet feed roller, the sheet separation member including: a body portion including a plurality of protrusion portions that engages with leading edges of the sheets of paper in a sheet feeding direction, and a plurality of arm portions supporting the protrusion portions respectively so that the protrusion portions are disposed at intervals in a stacking direction of the sheet A and plate spring portions formed around the body portion and integrally with the body portion in an arrangement direction of the protrusion portions so as to support the body portion in a predetermined region of the sheet supply device; wherein: separation loads applied to the sheets of paper from the protrusion portions engaged with the leading edges of the sheets of paper when one of the sheets of paper is fed by rotation of the sheet feed roller are set so that a separation load from a protrusion portion on a sheet-stacking-direction upper side is smaller than a separation load from any protrusion portion in an arrangement-direction center portion.

That is, in the sheet supply device including the pendulum type sheet feed roller, the sheet feed roller is brought into contact with the uppermost plane of the stacked sheets of paper by an urging force applied to the sheet feed roller from the support member. On this occasion, a contact force applied perpendicularly to the sheet surface from the sheet feed roller varies according to an angle between a longitudinal axis of the support member and the sheet plane (in other words, according to the number of stacked sheets of paper).

The contact force increases as the number of stacked sheets of paper decreases from the maximum (in other words, as the angle between the longitudinal axis of the support member and the sheet plane increases).

For this reason, the sheet conveyance force of the sheet feed roller decreases as the number of stacked sheets of paper increases and the position of the sheet of paper to be fed increases in level.

In the sheet separation member according to the embodiment, the separation loads applied to the corresponding sheets of paper from the protrusion portions disposed in the sheet stacking direction are set so that the separation load from the protrusion portion located on the sheet-stacking-direction upper side is smaller than the separation load from any protrusion portion in the arrangement-direction center portion. With this configuration, the separation loads of the respective protrusion portions are changed correspondingly to the sheet conveyance force of the sheet feed roller.

Accordingly, according to the sheet separation member described with respect to the embodiment, the stacked sheets of paper, particularly, sheets of paper ranging from the center portion to the upper side in the sheet stacking direction can be fed one by one surely without causing multiple sheet feed or no feed.

The protrusion portions are supported by the arm portions correspondingly, and the body portion constituted by the protrusion portions and the arm portions is supported by the plate springs formed in the arrangement direction of the protrusion portions, so that the separation loads applied to the sheets of paper from the protrusion portions can be set easily by adjusting the spring constants of the arm portions supporting the protrusion portions or the spring constants of the plate springs supporting the body portion. As a result, the sheet separation member according to the invention can be achieved easily without necessity of complicate design and manufacturing of the protrusion portions.

The body portion constituted by the protrusion portions and the arm portions are formed so as to be integrated with all the plate spring portions supporting the body portion, so that the “sheet separation portion and separation portion supporting portion” included in the sheet separation member according to the related art are formed by one member in the sheet separation member according to the invention. As a result, it is possible to reduce the total number of parts to thereby improve manufacturing efficiency, and it is possible to reduce cost of the sheet separation member.

At the time of sheet feed, sheet powder may be generated due to friction between the sheets of paper to be fed and the protrusion portions. Because most of the sheet powder falls down through gaps between the arm portions, it is possible to reduce the influence of the generated sheet powder on sheet separation.

According to the embodiment, there is provided a sheet separation member used in a sheet supply device for separating and feeding stacked sheets of paper one by one by rotation of a pendulum type sheet feed roller, the sheet supply device including the sheet feed roller brought into contact with a sheet plane by an urging force received from a long support member having one end pivoted and the other end attached to the sheet feed roller, the sheet separation member including: a body portion including a plurality of protrusion portions that engages with leading edges of the sheets of paper in a sheet feeding direction, and a plurality of arm portions supporting the protrusion portions respectively so that the protrusion portions are disposed at intervals in a stacking direction of the sheet A and plate spring portions formed around the body portion and integrally with the body portion in an arrangement direction of the protrusion portions so as to support the body portion in a predetermined region of the sheet supply device; wherein: separation loads applied to the sheets of paper from the protrusion portions engaged with the leading edges of the sheets of paper when one of the sheets of paper is fed by rotation of the sheet feed roller are set so that a separation load from a protrusion portion on a sheet-stacking-direction lower side is smaller than a separation load from any protrusion portion in an arrangement-direction center portion.

That is, in the sheet supply device including the pendulum type sheet feed roller, an anti-slip member constituted by a cork, etc. is provided in a bottom portion opposite to the sheet feed roller with respect to the sheets of paper so that multiple sheets of paper can be generally prevented from being fed collectively when the number of residual sheets of paper becomes small in the sheet storage portion storing the sheets of paper in a stack state. With this configuration, the sheet conveyance force of the sheet feed roller decreases when the number of residual stacked sheets of paper decreases (in other words, when an angle between the longitudinal axis of the support member and the sheet plane is near the maximum angle).

In the sheet separation member described above with respect to the embodiment, the separation loads applied to the corresponding sheets of paper from the protrusion portions disposed in the sheet stacking direction are set so that the separation load from the protrusion portion on the sheet-stacking-direction lower side is smaller than the separation load from any protrusion portion located in the arrangement-direction center portion. With this configuration, the separation loads of the respective protrusion portions are changed correspondingly to the sheet conveyance force of the sheet feed roller.

Accordingly, according to the sheet separation member described above with respect to the embodiment, multiple sheet feed or no feed generated when the number of residual stacked sheets of paper is small can be prevented so that the sheets of paper can be fed one by one surely.

The protrusion portions are supported by the arm portions correspondingly, the body portion constituted by the protrusion portions and the arm portions is supported by the plate springs formed in the arrangement direction of the protrusion portions, and the plate springs are formed so as to be integrated with the body portion. With this configuration, the sheet separation member can be achieved easily without necessity of complicated design and manufacturing of the protrusion portions in the same manner as in the aforementioned sheet separation member. At the same time, it is possible to improve manufacturing efficiency so as to achieve low cost of the sheet separation member and it is possible to reduce the influence of sheet powder generated at the time of sheet feed, on sheet separation.

Further, according to the embodiment, there is provided a sheet separation member used in a sheet supply device for separating and feeding stacked sheets of paper one by one by rotation of a pendulum type sheet feed roller, the sheet supply device including the sheet feed roller brought into contact with a sheet plane by an urging force received from a long support member having one end pivoted and the other end attached to the sheet feed roller, the sheet separation member including: a body portion including a plurality of protrusion portions that engages with the sheets of paper in a sheet feeding direction, and a plurality of arm portions supporting the protrusion portions respectively so that the protrusion portions are disposed at intervals in a stacking direction of the sheet And plate spring portions formed around the body portion and integrally with the body portion in an arrangement direction of the protrusion portions so as to support the body portion in a predetermined region of the sheet supply device; wherein: separation loads applied to the sheets of paper from the protrusion portions engaged with the leading edges of the sheets of paper when one of the sheets of paper is fed by rotation of the sheet feed roller are set so that a separation load from each of protrusion portions on sheet-stacking-direction upper and lower sides is smaller than a separation load from any protrusion portion in an arrangement-direction center portion.

Accordingly, in the sheet separation member, the separation loads applied to the corresponding sheets of paper from the protrusion portions disposed in the sheet stacking direction are set so that the separation load from each of the protrusion portions on sheet-stacking-direction upper and lower sides is smaller than the separation load from any protrusion portion in the arrangement-direction center portion.

As a result, according to the sheet separation member, the sheets of paper stored in the sheet storage portion of the sheet supply device can be always fed one by one surely regardless of the number of stacked sheets of paper so that multiple sheet feed or no feed can be prevented more surely from being generated at the time of sheet feed.

Accordingly, the sheet separation member can be achieved easily without necessity of complicated design and manufacturing of the protrusion portions. At the same time, it is possible to improve manufacturing efficiency so as to achieve low cost of the sheet separation member and it is possible to reduce the influence of sheet powder generated at the time of sheet feed, on sheet separation.

The sheet separation member may be formed from synthetic resin. It is preferable that the protrusion portions, the arm portions and the plate spring portions are all formed integrally from metal.

That is, when the sheet separation member is formed from metal, unlike the sheet separation portion made of resin according to the related art, the shape of each of the protrusion portions is unlikely to deform due to a temperature condition, a humidity condition etc., and the sheet separation member is unlikely to wear even after used for a long term. Thus, the sheet separation member can be given durability.

In order to set the separation loads applied to the sheets of paper from the protrusion portions, spring constants of the arm portions may be set individually, for example, by changing widths of the arm portions supporting the protrusion portions respectively.

Moreover, because the arm portions are provided for supporting the protrusion portions respectively and setting the arrangement positions of the protrusion portions, it is conceived that setting the spring constants of the arm portions individually is extremely laborious and the protrusion portions may not be supported well due to the setting of the spring constants.

In the sheet separation member, the separation loads of the protrusion portions may be set not by changing the spring constants of the arm portions directly supporting the protrusion portions but by changing the spring constants of the plate spring portions supporting the whole of the body portion constituted by the protrusion portions and the arm portions in the arrangement direction of the protrusion portions.

That is, according to the embodiment, the separation loads of the protrusion portions are configured by setting the spring constants of the plate spring portions provided in the arrangement direction of the protrusion portions (in other words, in the sheet stacking direction) in such a manner that a spring constant of a plate spring portion on a sheet-stacking-direction upper or lower side is smaller than a spring constant of any plate spring portion in a sheet-stacking-direction center portion.

Accordingly, the sheet separation member can be achieved easily compared with the case where the spring constants of the respective arm portions are adjusted individually.

The separation loads of the protrusion portions may be configured as follows.

That is, when the plate spring portions are constituted by a plurality of plate springs disposed on the body portion at intervals in the arrangement direction of the protrusion portions, the separation loads of the protrusion portions may be set by changing spring constants of the plate springs constituting the plate spring portions in the arrangement direction of the protrusion portions.

Or the separation loads of the protrusion portions may be set by changing arrangement density of the plate springs in the arrangement direction of the protrusion portions.

Specifically, for example, in order to set the separation loads of the protrusion portions, the width of each of the plate springs disposed on the sheet-stacking-direction upper or lower side may be reduced, compared with the width of any plate spring in the sheet-stacking-direction center portion, among the plate springs constituting the plate spring portions, and hence, the spring constant of the plate spring disposed on the sheet-stacking-direction upper or lower side may be reduced. With this configuration, the separation loads of the protrusion portions can be set easily.

For example, in order to set the separation loads of the protrusion portions, the arrangement density of the plate springs disposed on the sheet-stacking-direction upper or lower side may be reduced, compared with the arrangement density of the plate springs on the sheet-stacking-direction center portion, among the plate springs constituting the plate spring portions.

Incidentally, for the arrangement density of the plate springs to be changed, the interval between adjacent ones of the plate springs may be adjusted or the plate springs formed at substantially equal intervals may be partially eliminated.

In order to set the separation loads applied to the sheets of paper from the protrusion portions, the spring constants of the plate springs may be changed in the arrangement direction of the protrusion portions.

When the sheet separation member includes a fixation member shaped like a box in which the body portion can be received so that the fixation member supports the plate spring portions at end surfaces of its opposite side walls so as to fix the body portion to the sheet supply device while displaceably supporting the body portion, the separation loads of the protrusion portions may be set by changing a height of each of the side walls of the fixation member in the arrangement direction of the protrusion portions, the side walls supporting the plate spring portions.

That is, when the height of each of the side walls for supporting the plate spring portions in the fixation member is set so that the height of a section of the side wall on a sheet-stacking-direction upper or lower side is smaller than the height of a section of the side wall in a protrusion-portion-arrangement-direction center portion, the separation loads of the protrusion portions can be set so that a separation load of a protrusion portion on the sheet-stacking-direction upper or lower side is smaller than a separation load of any protrusion portion on the arrangement-direction center portion. With this configuration, the separation loads of the protrusion portions may be set by changing the height of each of the side walls for supporting the plate spring portions in the fixation member as described above.

According to the embodiment, there is provided a sheet supply device including: a sheet storage portion for receiving sheets of paper in a stack state; a pendulum type sheet feed roller attached to the other end of a long support member while one end of the long support member is pivoted, the pendulum type sheet feed roller being brought into contact with an uppermost plane of the sheets of paper stored in the sheet storage portion by an urging force received from the support member; and an inclined surface inclined at an obtuse angle with respect to the sheets of paper stored in the sheet storage portion on a downstream side in a feeding direction of the sheets paper by rotation of the sheet feed roller; wherein: a long hole is formed in the inclined surface in a stacking direction of the sheets of paper in the sheet storage portion; and the sheet separation member is provided so that protrusion portions of the sheet separation member pass through the long hole and protrude from the inclined surface.

According to the sheet supply device configured thus, the sheet separation member is used to cooperate with a pendulum type sheet feed roller to separate and feed stacked sheets of paper one by one. With this configuration, it is possible to feed sheets of paper one by one surely regardless of the number of the sheets of paper stored in the sheet storage portion.