Sheet feeding apparatus and image forming apparatus

A sheet feeding apparatus provided with a sheet stacking portion for supporting sheets thereon, a sheet feeding roller for feeding the sheets stacked on the sheet stacking portion, and a manually moving member for selectively moving the sheet stacking portion between a first position in which sheets stacked on the sheet stacking portion are brought into pressure contact with the sheet feeding roller and a second position in which the stacked sheets are spaced apart from the sheet feeding roller, the manually moving member being disposed above the sheet stacking portion and in a direction orthogonal to a sheet feeding direction, and an image forming apparatus having the sheet feeding apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a sheet feeding apparatus and an image forming apparatus designed such that sheets stacked on sheet stacking means are brought into pressure contact with sheet feeding means by a lever operation.

2. Description of the Related Art

An image forming apparatus such as a printer or a copying machine has heretofore been provided with a sheet feeding apparatus for feeding a sheet to an image forming portion. As such a sheet feeding apparatus, there is one provided with a cassette feeding portion for feeding sheets contained in a cassette loaded on the bottom of an image forming apparatus main body, and in addition, a multi-feeding portion which is a manually feeding portion designed to stack sheets on a tray drawably or openably and closably provided in the image forming apparatus main body, and feed the sheets by a sheet feeding roller.

FIG. 12of the accompanying drawings schematically shows the construction of a conventional image forming apparatus provided with such a multi-feeding portion, and inFIG. 12, the multi-feeding portion140is openably and closably provided in an image forming apparatus main body100, and is provided with a tray145for stacking sheets P thereon, and a sheet feeding roller143rotated in conformity with an image forming operation during image forming to thereby feed the sheets P from the tray145.

Also, a cassette feeding portion116is provided with a cassette117loaded on the bottom of the image forming apparatus main body100, a sheet feeding roller118provided in the image forming apparatus main body100for feeding sheets P stacked on the intermediate plate117aof the cassette117and a pair of retard rollers119for separating the sheets P one by one.

Design is made such that when the sheets P are to be fed from the multi-feeding portion140to an image forming portion101, the sheets P are fed one by one from the tray145by the sheet feeding roller143. Also, design is made such that when the sheets P are to be fed from the cassette feeding portion116to the image forming portion101, the sheets P contained in the cassette are separated and fed one by one by the sheet feeding roller118and the pair of retard rollers119. The sheets P thus fed from the multi-feeding portion140or the cassette feeding portion116are thereafter transported to the image forming portion101, whereby images are formed thereon.

FIG. 13of the accompanying drawings shows the construction of such a multi-feeding portion140, and inFIG. 13, an intermediate plate146provided below a sheet feeding roller143for pivotal movement in a vertical direction is downwardly pivotally moved as shown inFIG. 14of the accompanying drawings when the sheets are to be set on the tray145, and by the intermediate plate146being thus pivotally moved, a gap “a” equal to or greater than the thickness of the sheets to be set is formed between the sheet feeding roller143and the intermediate plate146.

By the gap “a” being thus formed between the sheet feeding roller143and the intermediate plate146, the sheets P can be pushed into between the sheet feeding roller143and the intermediate plate146. Thereafter, as shown inFIG. 15of the accompanying drawings, the intermediate plate146is upwardly pivotally moved, whereby the sheets P can be brought into pressure contact with the sheet feeding roller143, whereby when the sheet feeding roller143is rotated, the sheets P come to be fed out. The reference numeral147designates a frictional pad adapted to pressure-contact with the sheet feeding roller143, and design is made such that the sheets P can be separated one by one by this frictional pad147.

Now, such an intermediate plate is also provided in the cassette117of the cassette feeding portion116, as shown inFIG. 12. In the cassette feeding portion116, design is made such that when the cassette117is contained in the image forming apparatus main body after the sheets P have been set in the cassette117, an intermediate plate117ais automatically pivotally moved to a position shown inFIG. 12.

On the other hand, in the multi-feeding portion140, it is also possible to adopt a construction similar to that of the cassette feeding portion116, but a sheet feeding operation is possible with the tray145opened and therefore, with economical properties such as a manufacturing cost and a running cost further taken into account, design is made such that a lever148which is manually moving means shown inFIG. 16of the accompanying drawings is manually operated in a vertical direction to thereby pivotally move the intermediate plate146in the vertical direction.

However, in the conventional image forming apparatus provided with the multi-feeding portion140designed such that the intermediate plate146is pivotally moved by such a lever operation, this lever148, as shown inFIGS. 13 and 16, is disposed in opposed relationship in a direction (hereinafter referred to as the widthwise direction) orthogonal to the sheet transport direction of the tray145, and is at a location hidden by a side regulating plate149for regulating the position of the sheets in the widthwise direction thereof and therefore, in some cases, a user loses sight of the lever148.

When the user thus loses sight of the lever148, the user forgets the lever operation, and when the user thus forgets the lever operation, for example, forgets the operation of upwardly pivotally moving the lever148, the sheets cannot be pushed in below a sheet feeding roller143and therefore, faulty feeding occurs.

Also, when the user forgets the downwardly pivotally moving operation, the sheets cannot be brought into pressure contact with the sheet feeding roller143and therefore, even if the sheet feeding roller143is rotated, the sheet cannot be fed out, or cannot be fed out to the image forming portion101at predetermined timing.

Notes150are provided near the lever148, for example, outside the sheet stacking portion145aof the tray145so that the user may not forget the operation even if he notices the lever148, but the notes150provided at such a location are difficult to visually perceive and in some cases, the user does not notice them. When as described above, the user forgets the lever operation even if he notices the lever148, the sheets cannot be fed.

SUMMARY OF THE INVENTION

So, the present invention has been made in view of such a situation, and has as its object to provide a sheet feeding apparatus which enables a lever to be reliably operated to thereby feed sheets reliably, and an image forming apparatus provided with the same.

The present invention provides a sheet feeding apparatus provided with:sheet stacking means for supporting sheets thereon;sheet feeding means for feeding the sheets stacked on the sheet stacking means; anda manually moving member for selectively moving the sheet stacking means to a first position in which the sheets stacked on the sheet stacking means are brought into pressure contact with the sheet feeding means, or a second position in which the stacked sheets are spaced apart from the sheet feeding means,wherein the manually moving member is disposed above the sheet stacking portion of the sheet stacking means and in a direction orthogonal to a sheet feeding direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1schematically shows the construction of a copying machine which is an example of an image forming apparatus according to the embodiment of the present invention.

InFIG. 1, a scanner portion30which is an image reading portion is disposed in the upper portion of the copying machine main body (hereinafter referred to as the apparatus main body)200A of the copying machine200, an image forming portion40for forming an image on a sheet P is disposed in the central portion of the apparatus main body, and a cassette feeding portion16and a multi-feeding portion50for feeding the sheet P to the image forming portion40are disposed in the lower portion of the apparatus main body.

The image forming portion40has an electrophotographic photosensitive drum (hereinafter referred to as the photosensitive drum)41, a developing device42, etc. design is made such that when a laser beam corresponding to image information emitted from a laser scanner43is scanned on the surface of the photosensitive drum41, a latent image is formed on the surface of the photosensitive drum, and this latent image is developed by the developing device42, whereby a toner image is formed on the surface of the photosensitive drum.

Also, design is made such that when the sheet is thereafter transported to a transferring portion constituted by the photosensitive drum41and a transfer charging device44, as will be described later, the toner image formed on the photosensitive drum41is transferred to the sheet.

On the other hand, the cassette feeding portion16is for feeding the sheets P to the transferring portion, and is provided with a cassette17loaded on the bottom of the apparatus main body200A, and a sheet feeding roller18for feeding the sheets P contained in this cassette17. Design is made such that during image forming, the sheet feeding roller18and a pair of retard rollers19are rotated in conformity with an image forming operation so as to separate and feed the sheets P one by one from the cassette17.

The multi-feeding portion50is also for feeding the sheets P to the transferring portion, and is provided with a tray4which is sheet stacking means openably and closably provided in the apparatus main body200A, and a sheet feeding roller2which is sheet feeding means for feeding the sheets P stacked on the tray4. Design is made such that during image forming, the sheet feeding roller2is rotated in conformity with the image forming operation so as to feed the sheets P one by one from the tray.

On the other hand, the scanner portion30is for reading the image of an original placed on an original glass stand301, and is adapted to convert image information into an electrical image signal after it has read the image of the original, and input this image information converted into the electrical image signal to the laser scanner43of the already described image forming portion40.

Description will now be made of the image forming operation of the copying machine constructed as described above.

First, when the image information of the original is read by the scanner portion30, this image information is image-processed and is thereafter converted into an electrical signal, and is transmitted to the laser scanner43of the image forming portion40. In some cases, the image information is inputted from an external device such as a personal computer (not shown) to the image forming portion40.

In the image forming portion40, the surface of the photosensitive drum41is scanned by a laser beam corresponding to the image information emitted from the laser scanner43to thereby form a latent image on the photosensitive drum, whereafter this latent image is developed by the developing device42to thereby form a toner image on the surface of the photosensitive drum41.

On the other hand, when in parallel to this operation, the sheets P are to be fed from the multi-feeding portion50to the image forming portion40, the sheets P are fed one by one from the tray by the sheet feeding roller2. Also, design is made such that when the sheets P are to be fed from the cassette feeding portion16, the sheets P contained in the cassette are separated and fed one by one by the sheet feeding roller18and the pair of retard rollers19.

The sheet P thus fed from the multi-feeding portion50or the cassette feeding portion16is then transported to register rollers20. At this time, the register rollers20are at a halt, whereby the sheet P has its skew feed corrected, and is once stopped and stands by at this position.

Thereafter, the register rollers20are rotated and the sheet P having stood by is fed to the transferring portion constituted by the photosensitive drum41and the transfer charging device44in timed relationship therewith, and when the sheet P passes through this nip part, the toner image on the photosensitive drum is transferred to the sheet P.

The sheet P to which the toner image has been transferred in this manner is transported to a fixing apparatus45, and the sheet P is heated and pressurized when it passes through the fixing apparatus45, whereby the toner image is fixed on the surface of the sheet P. The sheet P on which the toner image has been thus fixed is thereafter delivered to a delivery tray47by sheet delivery rollers46.

FIG. 2is a perspective view illustrating the construction of the multi-feeding portion50.

InFIG. 2, the reference numeral1designates an intermediate plate provided on that end portion of the tray4which is adjacent to the sheet feeding roller, i.e., below the sheet feeding roller2, for pivotal movement (movement) in a vertical direction, and when the sheets are to be set on the tray4, the intermediate plate1is adapted to be downwardly pivotally moved as shown inFIG. 6which will be described later, and by the intermediate plate1being thus downwardly pivotally moved, a gap “a” equal to or greater than the thickness of the sheets to be set is formed between the sheet feeding roller2and the intermediate plate1.

Also, when the sheets are to be fed, the intermediate plate1is adapted to be upwardly pivotally moved as shown inFIG. 5which will be described later, and by the intermediate plate1being thus upwardly pivotally moved, the sheets can be brought into pressure contact with the sheet feeding roller2, whereby when the sheet feeding roller2is rotated, the sheets come to be fed out.

A lever8which is a manually moving member for downwardly pivotally moving the intermediate plate1is provided above the sheet stacking portion4aof the tray4and in a direction orthogonal to a sheet feeding direction. The opposite ends of this lever8are provided near side regulating plates6which are regulating members provided outside the opposite sides of the tray4and adapted to contact with the opposite side edge portions of the sheet and regulate the side edge positions of the sheet.

In the present embodiment, the lever8is provided so as to be astride of the side regulating plates6and the tray4, and by the lever8being thus provided so as to be astride of the side regulating plates6and the tray4, the size of the lever8can be made large, whereby the operability and visual perceptibility of the lever8can be improved.

Also, the lever8is disposed near the side regulating plates6used by the user in an ordinary operation, the visual perceptibility of the lever8is improved and the user can be prevented from losing sight of the presence of the lever8. Further, as in the present embodiment, the lever8is provided so as to be astride of the side regulating plates6and the tray4, whereby the lever8can be supported at the opposite end portions thereof and therefore, the rigidity of the lever8can be secured.

Furthermore, on the upper surface of the lever8, there is formed an indicating portion8acomprised of an index, an index label or the like indicating a user's operation or the like, as shown inFIG. 3. If required, this indicating portion8amay also be formed on the back or the like of the lever8.

The lever8is located above the sheet stacking portion4aof the tray4and therefore, as the user looks at the lever8when he sets the sheets on the tray4, the user comes to look at the indicating portion8aformed on the upper surface of the lever8and thus, the visual perceptibility of the indicating portion8aheightens, and it never happens that the effect thereof as an index is lost.

FIGS. 4A and 4Bshow the construction of the connection between the lever8and the intermediate plate1, and the lever8, as shown inFIGS. 4A and 4B, is supported on the tray4for pivotal movement in a vertical direction through a shaft4bprovided on the side portion of the tray4, is supported to maintain an opening between lever8and tray4, and is connected to the intermediate plate1pivotally supported through a link mechanism25. Also, the intermediate plate1is upwardly biased by a spring26.

When the lever8is downwardly pivotally moved as shown inFIGS. 4A and 5, the intermediate plate1is upwardly pivotally moved through the link mechanism25, and the intermediate plate1is upwardly biased by the spring26and the sheets P come into pressure contact with the sheet feeding roller2.

Also, when the lever8is upwardly pivotally moved as shown inFIGS. 4B and 6, the intermediate plate1is downwardly pivotally moved through the link mechanism25against the biasing force of the spring26, whereby a gap “a” equal to or greater than the thickness of the sheets to be set is formed between the sheet feeding roller2and the intermediate plate1, and the sheets P can be pushed in to below the sheet feeding roller2. InFIGS. 5 and 6, a separating pad holder3A holding the separating pad3on the upper end portion thereof is biased in a direction to bring the separating pad3into pressure contact with the sheet feeding roller2by biasing means, not shown.

Now, as shown inFIG. 7, on the underside of the lever8, there is pivotally supported a sheet stopper11which is a stopper member adapted to contact with or become proximate to the sheet stacking portion4aof the tray when the lever8is downwardly pivotally moved as shown inFIG. 7. By such a sheet stopper11being provided, when the lever8is downwardly pivotally moved and the intermediate plate1has been moved to a first position in which the sheets P are brought into pressure contact with the sheet feeding roller2, if an attempt is made to insert the sheets P, the insertion of the sheets P into between the sheet feeding roller2and the intermediate plate1is hampered by the sheet stopper11, as shown inFIG. 7.

Design is made such that when the lever8has been thus downwardly pivotally moved, the insertion of the sheets P is hampered by the sheet stopper11, that is, the sheets P cannot be inserted when the lever8is in its downwardly pivotally moved state, whereby when the user has forgotten the lever operation, the user can be made to recognize that he has forgotten the lever operation.

On the other hand, when as shown inFIG. 6, the lever8has been upwardly pivotally moved and the intermediate plate1has been moved to a second position in which the sheets P are spaced apart from the sheet feeding roller2, that is, when the insertion (push-in) of the sheets P has become possible, the sheet stopper11separates from the sheet stacking portion4aof the tray4and the sheets P become insertable. Thereby, the sheets P can be inserted, and the sheets P are set normally between the sheet feeding roller2and the intermediate plate1.

When the lever8is downwardly pivotally moved after the lever8has been thus upwardly pivotally moved and the sheets P have been inserted, the sheet stopper11abuts against the sheets P as shown inFIG. 5, but as already described, the sheet stopper11is pivotally supported on the underside of the lever8and therefore, after it has abutted against the sheet P, it is upwardly pivotally moved. Thereby, even if the lever8is downwardly pivotally moved with the sheets P inserted (set), the sheet stopper11is kept in a position in which it contacts with the sheets P, and it never brings about an ill effect to the transport of the sheets P.

Also, the downwardly pivotally moved position of this sheet stopper11is regulated by a restraining member (not shown), and therefore, even when the lever8is upwardly pivotally moved as shown inFIG. 6, the sheet stopper11is held in a position in which the sheets P are insertable.

As described above, when the user has forgotten the operation of the lever8when he inserts the sheets P, the insertion of the sheets P is hampered by the sheet stopper11provided on the lever8, whereby it can be suggested to the user that the operation of the lever8is necessary. Thereby, the user can reliably operate the lever8to thereby effect the changeover of a state in which sheet feeding is possible and a state in which the insertion of the sheets P is possible.

FIG. 8is a perspective view showing the construction of the intermediate plate1. InFIG. 8, an intermediate plate sheet13is provided at a location opposed to the sheet feeding roller2, and an auxiliary intermediate plate sheet14is disposed upstream of the intermediate plate sheet13.

By providing such an intermediate plate sheet13and such an auxiliary intermediate plate sheet14, it is possible to give moderate back tension to the sheets P and therefore, double feed, and particularly, bundle double feed caused by a sheet bundle coming into between the sheet feeding roller2and the separating pad3can be prevented.

Cork or a rubber material such as urethane is suited as the material of the intermediate plate sheet13so as to be capable of standing the state of contact with such a sheet feeding roller2because the intermediate plate sheet13contacts with the sheet feeding roller2when the sheets are not stacked. Also, a material having a fur-like surface is suited as the material of the auxiliary intermediate plate sheet14because the auxiliary intermediate plate sheet14does not contact with the sheet feeding roller2and is not positively pressed through the sheets P.

Also, as shown inFIG. 8, regulating members15are provided on the intermediate plate1with the sheet feeding roller2interposed therebetween in order to prevent the sheet P from being off in the widthwise direction of the sheet P. These regulating members15may be formed integrally with the intermediate plate1, or may be stuck on the intermediate plate1.

Each of these regulating members15is provided with an inclined surface15afacing the sheet feeding roller2, as shown inFIG. 9. By the regulating members15being provided with such inclined surfaces15a, even when during sheet feeding shown inFIG. 10, the sheets P deviate in the widthwise direction thereof relative to the sheet feeding roller2, the sheets P have their deviation regulated by the regulating members15and it becomes possible to effect good transport.

While in the description hitherto made, a case where the lever8is disposed so as to be astride of the side regulating plates6and the tray4has been described, the present invention is not restricted thereto, but the lever8can be disposed so that at least one end thereof may be located near one of the side regulating plates6provided in opposed relationship with each other. As shown, for example, inFIG. 11, a lever12may be disposed, without being astride of the side regulating plates6, so that one end thereof may be located near one of the side regulating plates6.

Even if the lever12is thus disposed so that one end thereof may be located near one of the side regulating plates6and the lever12is supported in a cantilevered state, the lever12is present on the sheet stacking portion4aof the tray4and therefore, a similar effect can be obtained.

Also, while in the description hitherto made, a case where the intermediate plate1provided on the fore end side of the tray4and supporting the leading edge side of the sheets is made pivotally movable in the vertical direction has been described as an example, the present invention is not restricted thereto, but can also be applied to a case where the tray supporting the whole of the sheets is pivotally movable in the vertical direction.