JPH10129859A - Sheet feed device and picture image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the contact of sheet with a feed means by regulating an interval between a small size cassette and a guide means when a sheet cassette is attached on and deteched from a sheet feed device main body in a condition in which the small size cassette is mounted on the sheet cassette. SOLUTION: The height of a pressing claw 26a is set to a lower position than an evacuation position of a pick up roller 9 in a condition in which a sheet guide 8 is mounted on a sheet supply and feed device main body. An interval (t) between a regulation member 34a formed in a right inlet guide 34 and an interval regulation member 32 is constituted in such a manner that it is smaller than an interval T between the pick up roller 9 and the claw 26a. Consequently, the interval regulation member 32 bumps against the regulation member 34a before the claw 26a bumps against the pick up roller 9, even if a sheet cassette 8 is lifted when it is taken out. For this reason, an envelope pressed by the claw 26a when the sheet cassette 8 is taken out does not come into contact with the pick up roller 9, and a tip of the envelope does not come off from the claw 26a, thereby causing no improper loading of sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus used for a copying machine, a printer, and the like, and an image forming apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, in a copying machine, a printer, or the like, in order to automatically feed sheets, a large number of sheets are stacked and set on a sheet stacking device, and the sheets are fed by a feeding roller or the like. They are separated and fed one by one.
In many cases, a cassette accommodating sheets is detachable so that sheets of different sizes can be fed.

Recently, there is a demand in the market to continuously feed small-sized sheets such as envelopes having a small width.

[0004]

However, in the conventional automatic sheet feeding, swelling like an envelope occurs,
When a sheet having a flap is stacked and fed, an expanded envelope or an envelope with the flap opened may collide with a feeding port, and a feeding failure may occur.

Further, when the sheet cassette is taken out of the apparatus body while being lifted upward, the upper surface of the sheet comes into contact with the feeding roller, and the leading end of the sheet is disengaged from the holding claws or the like, resulting in improper stacking or feeding. When the user attempts to perform a jam (paper jam) process by pulling out the cassette when the sheet is jammed, the jammed sheet may be caught on a cassette rail for attaching and detaching the cassette.

[0006] The present invention is to solve the above problems,
An object of the present invention is to provide a sheet feeding apparatus capable of feeding small-sized sheets like an envelope and preventing a loaded sheet from contacting a feeding roller or the like when a cassette is attached or detached, and a sheet feeding apparatus using the same. To provide an image forming apparatus.

[0007]

A representative configuration according to the present invention for achieving the above object is a sheet feeding apparatus in which a sheet cassette can be attached to and detached from an apparatus main body. A small-size cassette that can be attached and detached, guide means for guiding the attachment / detachment of the sheet cassette, and feeding means for feeding sheets loaded in the sheet cassette or the small-size cassette. When the sheet cassette is attached to and detached from the apparatus main body in a state where the size cassette is mounted on the sheet cassette, an interval regulating means for regulating an interval between the small size cassette and the guide means is provided.

In the above configuration, when the small size cassette is mounted on the sheet cassette and the sheet cassette is attached to and detached from the apparatus main body, a constant distance is maintained between the sheet surface loaded by the interval regulating means and the feeding means. Is maintained, the sheet can be prevented from contacting the feeding means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a sheet feeding apparatus according to the present invention and an image forming apparatus using the same will be specifically described with reference to the drawings.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an explanatory view of the overall configuration of an image forming apparatus using a sheet feeding apparatus, FIG. 2 is an explanatory view of a configuration of a sheet cassette, and FIG. 3 is an explanatory view of a configuration in which a small size cassette is mounted on the sheet cassette. FIG. 4 is an explanatory diagram of a configuration of a small-sized cassette, FIG. 5 is an explanatory diagram of a configuration of a sheet cassette attaching / detaching guide means, and FIG. 6 is an explanation of a case where a small-sized cassette is mounted and small-sized sheets such as envelopes are fed. FIG.

Here, as the order of the description, first, the overall configuration of the image forming apparatus will be described, and then the configurations of the sheet stacking apparatus and the sheet feeding apparatus will be described.

{Description of Overall Configuration of Image Forming Apparatus} In FIG. 1, a main body A of the image forming apparatus has a scanner section B serving as image reading means for reading image information on the image surface of a book document, and a lower section thereof. An image forming section C serving as an image forming means is provided, and a sheet feeding device D is further assembled below the image forming section C.

The scanner section B includes a scanning system light source 1, a platen glass 2, an original pressure plate 3, which can be opened and closed with respect to the apparatus main body A, a mirror 4, a lens 5, a light receiving element (photoelectric conversion element) 6, and an image processing section. And so on. Then, a book document, a sheet document, or the like such as a book, cardboard, or curled paper is placed on the platen glass 2 with the document surface facing down.
The back side is pressed by the document pressing plate 3 and set in a stationary state.
When the reading start key is pressed, the scanning system light source 1 scans the lower part of the platen glass 2 in the direction of arrow a in FIG. Image information of a document read by the scanning system light source 1 is processed by an image processing unit, converted into an electric signal, and transmitted to a laser scanner 7 as an optical system.

Here, the image forming apparatus main body A functions as a copying machine when the processing signal of the image processing section is input to the laser scanner 7, and functions as a printer when the output signal of the personal computer is input. If a transmission signal from a facsimile device of another device is input or a processing signal of the image processing unit is transmitted to a facsimile device of another device, the device functions as a facsimile device.

On the other hand, a sheet cassette 8 is mounted below the image forming section C. The sheet cassette 8 is composed of a lower cassette 8a and an upper cassette 8b as one feeding unit. In this embodiment, three feeding units U1, U2, and U3 are mounted, and six cassettes are mounted. One upper feeding unit U1 is detachably attached to the apparatus main body A, and two lower feeding units U2 and U3 are detachably attached to the sheet feeding device D.

The sheets accommodated in the cassettes 8a and 8b are fed out by a pickup roller 9 which is a feeding rotating body as will be described later, and are fed by a feed roller (rotating roller for applying a feeding force to the sheets) constituting a separating means. The sheet is separated and fed one by one by the cooperation of a retarder (rotating body for applying a separating force to the sheet) 11 and then conveyed by conveying rollers 12 and 13 constituting a conveying means. The sheet is guided by the roller 14 and fed to the image forming section C by the roller 14 in synchronization with the image forming operation.

The image forming section C includes an electrophotographic photosensitive drum 1
5, image writing optical system 16, developing unit 17, and transfer charger 1
8 and so on. A laser beam corresponding to image information emitted from the laser scanner 7 is scanned by the image writing optical system 16 on the surface of the photosensitive drum 15 uniformly charged by the charger to form a latent image. A toner image is formed on the image by the developing device 17, and the toner image is transferred onto the first surface of the sheet by the transfer charger 18 on the sheet conveyed in synchronization with the rotation of the photosensitive drum 15 by the registration roller 14.

In FIG. 1, reference numeral 19 denotes a conveying belt for conveying a sheet on which a toner image is formed, reference numeral 20 denotes a fixing device, and reference numeral 21 denotes a fixing device.
Denotes a discharge roller. The sheet on which the toner image is formed is conveyed to the fixing device 20 by the conveyance belt 19, and is heated and pressed to fix the toner image on the sheet surface.
The sheet is discharged and stacked on a tray 22 disposed outside the apparatus by discharge rollers 21.

When images are recorded on both sides of the sheet, the sheet discharged from the fixing device 20 is discharged
When the rear end of the sheet passes the branch point 23, the discharge roller 21 rotates in the reverse direction, and the sheet is once placed on the double-sided tray 24, and is then conveyed by the conveying rollers 12 and 13,
The sheet that has reached the registration roller 14 and has been inverted is formed with an image on the second surface in the same manner as described above, and then discharged and stacked on the tray 22.

In the sheet feeding device D, as described above, the sheets stacked and stored in the lower cassette 8a or the upper cassette 8b are sequentially fed by the pickup roller 9, and the upper and lower cassettes 8a and 8b are respectively It is configured as shown in FIG.

In FIG. 2, reference numeral 8c denotes a main cassette main body, which includes a side regulating member 8d for regulating the widthwise end of the normal size sheet S1 and a rear end regulating member 8e for regulating the rear end in the sheet feeding direction. A sheet storage portion is formed. The sheet accommodating portion is provided with an opening 8f, and is provided with a middle plate 8h rotatably supported about a hinge 8g so as to cover the opening 8f.

As will be described later, the cassette body 8c
It is detachable by inserting and pulling it out along the cassette guide with respect to the image forming apparatus main body.
The middle plate 8h is mounted on the cassette body 8c in the image forming apparatus main body, and is lifted by a lifter 36 (see FIG. 5) disposed below the opening 8f during sheet feeding, and the uppermost sheet is moved. The sheet height is regulated by abutting against a not-shown claw, and the top of the sheet S1 stacked and stored on the middle plate 8h is stopped at a position where it can be fed by the pickup roller 9.

The cassette main body 8c is adapted to allow a small-sized cassette to be mounted.

{Description of Configuration of Sheet Feeding Apparatus} Next, a description will be given of the sheet stacking apparatus and a sheet feeding apparatus mounted thereon to feed a sheet.

As described above, the middle plate 8h of the cassette main body 8c is detachable from the hinge portion 8g. When the middle plate 8h is removed, as shown in FIG. Insertion hole 8i which constitutes mounting means for removably mounting the envelope-dedicated cassette E which is
Is provided. On the other hand, the bottom plate 25 of the cassette E
a is formed with a pin 25b protruding at a position corresponding to the insertion hole 8i. The pin 25b is inserted into the insertion hole 8i, is rotatably mounted on the hinge 8g, and is pulled out to be used exclusively for envelopes. Cassette E into cassette body 8c
It can be attached to and detached from.

The envelope-dedicated cassette E is loaded with an envelope having a flap as a sheet, an envelope which easily expands, or a small-size sheet smaller than a normal-size sheet such as a postcard, and feeds it to the image forming means to be addressed. This is used when printing names and the like. Therefore, the sheet fed in the present embodiment is not only a so-called cut sheet,
This is a concept that includes envelopes and the like.

FIG. 4 is a perspective view of the cassette E for envelopes. In FIG. 4, reference numeral 26 denotes a side regulating plate for regulating an end in the width direction of the envelope. This can be adjusted to various sizes of envelope width by a method not shown. The rear end regulating member 8e also serves as a member for regulating the rear end of the envelope in the feeding direction when the cassette E for exclusive use of the envelope is mounted on the sheet cassette 8.

An intermediate plate 27 is mounted between the side regulating plates 26, and is supported only by a spring 28 mounted on the bottom plate 25a and is pressed upward. As a result, the middle plate 27 is constantly pushed upward, and the envelope loaded thereon comes into contact with the claw 26a provided on the side regulating plate 26, so that the pickup roller 9 stands by at the feedable position. ing.

Further, the side regulating plate 26 is provided with a pressing member 29 for suppressing the swelling of the envelope to be loaded and the opening of the flap. The holding member 29 is provided on both side regulating plates.
It is rotatably supported on 26. In this embodiment, a pair of the pressing members 29 are provided at positions facing the side regulating plates 26.

Further, a locking projection 27a is provided on the middle plate 27, and the locking projection 27a is engaged with a guide groove 26b provided on the side regulating plate 26. This prevents the middle plate 27 from rising above a certain level.

Reference numeral 30 denotes a screw for fixing the side regulating plate 25c, which fixes the side regulating plate 26 slid according to the size of the envelope. Reference numeral 31 denotes an envelope leading end restricting plate which serves as a right guide wall in the cassette insertion direction when the envelopes are stacked.

An interval regulating member 32 is integrally formed on the top of the tip regulating plate 31. This interval regulating member 32
As described later, the distance regulating means is constituted by the upper regulating member provided on the cassette guide means.

The space regulating member 32 is provided outside the side regulating plate 26 on the front side in the sheet cassette inserting direction with respect to the apparatus main body, and is used when the sheet cassette 8 loaded with the envelope cassette E is loaded into the apparatus main body. , The feed roller 10 and the retard roller 11 are arranged at a height near the nip position.

Next, a description will be given of guide means for guiding the sheet cassette 8 loaded with the envelope-dedicated cassette E into and out of the apparatus main body. This is configured as shown in FIG. In FIG. 5, the sheet cassette 8 is inserted in the direction of arrow A, mounted on the apparatus main body, and transports sheets in the direction of arrow B.

In FIG. 5, a right guide plate 33 is provided on the right side in the cassette insertion direction of the sheet cassette 8, and a U-shaped right entrance guide is provided on the front side in the cassette insertion direction.
34 are provided. On the left side in the cassette insertion direction, an inverted U-shaped left guide plate 35 is provided. The sheet cassette 8 can be attached to and detached from the apparatus main body by inserting and extracting the sheet cassette 8 along the guide plate 33, the guide 34, and the guide plate 35 along the same.

The entrance guide 34 has an upper regulating member 34 against which the spacing regulating member 32 of the above-described envelope dedicated cassette E can abut.
a is formed integrally. The entrance guide 34 and the upper regulating member 34a are disposed outside the sheet feeding width area. The height of the upper regulating member 34a is configured to be located near the nip between the feed roller 10 and the retard roller 11.

In a state where the sheet guide 8 having the envelope cassette E mounted thereon is mounted on the apparatus main body by the guide means, the height of the holding claw 26a is lower than the retracted position of the pickup roller 9, as shown in FIG. And the interval t between the upper regulating member 34a formed on the right entrance guide 34 and the interval regulating member 32 is smaller than the interval T between the pickup roller 9 and the claw 26a. is there.

Therefore, when the sheet cassette 8 is taken out, even if the cassette 8 is lifted, the space regulating member 32 strikes the upper regulating member 34a before the pawl 26a strikes the pickup roller 9. For this reason, the sheet cassette 8
When the paper is taken out, the envelope pressed by the claw 26a does not contact the pickup roller 9, and the tip of the envelope is
There is no possibility that the load will not be deviated from a.

The height of the right guide plate 33 is lower than the nip portion between the feed roller 10 and the retard roller 11 and lower than the tangent connecting the holding claw 26a and the nip portion. I have. For this reason, as shown in FIG. 6, even if the sheet cassette 8 is pulled out from the apparatus main body in a state where the leading end of the small size sheet S2 is in the vicinity of the nip portion, the sheet S2 does not catch on the right guide plate 33. The sheet cassette 8 can be pulled out smoothly.

Further, when pulling out the cassette, the cassette 8
The left side is guided by the left guide plate 35, and the right side is guided by the length of the right entrance guide plate 34 in the vertical direction. This length is determined by the pickup roller 9, the feed roller 10,
Since the length of the retard roller 11 is longer than that of the retard roller 11, it is possible to prevent the small size sheet S2 such as an envelope from being caught on the end of the roller.

[Other Embodiments] In the above-described first embodiment, an example is shown in which the space regulating member 32 provided in the envelope dedicated cassette E is formed integrally with the leading end regulating plate 31, but as shown in FIG. , Formed separately from the tip regulation plate 31, and the spacing regulation member 32
May be fixed to the distal end regulating member 31 with a screw 38 through a long hole 37 provided in the end portion. With this configuration, the height of the gap regulating member 32 can be adjusted within the range of the long hole.

In the above embodiment, the case where the electrophotographic image forming means is applied as the image forming means has been described. However, the image forming means having an ink jet head, a thermal head or the like as another image forming means is described. It is also possible to apply the present invention to an image forming apparatus equipped with.

In the above-described embodiment, the feeding means has a roller shape such as a pickup roller or a feed roller. However, the feeding means is not limited to a roller, but may be an endless belt or the like stretched between pulleys. May be done.

[0044]

The present invention is constructed as described above.
With the small cassette installed in the sheet cassette,
When the sheet cassette is attached to and detached from the apparatus main body, a fixed interval is maintained between the sheet surface loaded by the interval regulating means and the feeding means, so that the sheet can be prevented from contacting the feeding means. is there.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an overall configuration of an image forming apparatus using a sheet feeding device.

FIG. 2 is an explanatory diagram of a configuration of a sheet cassette.

FIG. 3 is an explanatory diagram illustrating a configuration in which a small size cassette is mounted on a sheet cassette.

FIG. 4 is an explanatory diagram of a configuration of a small size cassette.

FIG. 5 is an explanatory diagram of a configuration of a sheet cassette attaching / detaching guide unit.

FIG. 6 is an explanatory diagram when a small-sized cassette is mounted and small-sized sheets such as envelopes are fed.

FIG. 7 is an explanatory view of an embodiment in which the height of the interval regulating member is adjustable.

[Explanation of symbols]

 A: Image forming apparatus main body B: Scanner section C: Image forming section D: Sheet feeding apparatus E: Envelope cassette S1: Sheet U1: Feeding unit U2: Feeding unit U3: Feeding unit 1: Scanning light source 2 ... Platen glass 3. Original pressure plate 4. Mirror 5. Lens 7. Laser scanner 8. Sheet cassette 8 a. Lower cassette 8 b. Upper cassette 8 c. Cassette main body 8 d. Part 8h… Medium plate 8i… Fit hole 9… Pickup roller 10… Feed roller 11… Retard roller 12… Transport roller 13… Transport roller 14… Registration roller 15… Photoconductor drum 15… Electrophotosensitive drum 16… Optical system 17 … Developer 18… Transfer charger 19… Conveyer belt 20… Fixing device 21… Discharge roller 22… Tray 23… Branch point 24… Double-sided tray 25a… Bottom plate 25b… Pin 26… Side regulating plate 26a… Claw 26b… Guide groove 27… Medium plate 27a… Locking projection 28… Spring 29… Holding member 30… Screw 31… Envelope tip regulation plate 32… Space Control member 33… Right guide plate 34… Right entrance guide 34a… Upper control member 35… Left guide plate 36… Lifter 37… Long hole 38… Screw

Claims (7)

[Claims] 1. A sheet feeding device in which a sheet cassette is detachable from an apparatus main body, a sheet cassette, a small size cassette detachable from the sheet cassette, and guide means for guiding the detachment of the sheet cassette. And a feeding unit for feeding sheets loaded in the sheet cassette or the small size cassette, wherein the sheet cassette is attached to and detached from the apparatus main body in a state where the small size cassette is mounted on the sheet cassette. A sheet feeding device, further comprising an interval regulating means for regulating an interval between the small-sized cassette and the guide means. 2. The sheet feeding device according to claim 1, wherein said gap regulating means comprises a gap regulating member provided on said small size cassette and an upper regulating member provided on a guide means. 3. The sheet feeding device according to claim 2, wherein the spacing regulating member provided on the small size cassette is attached to the small size cassette main body so as to be adjustable in height. 4. The sheet feeding apparatus according to claim 2, wherein the space regulating member is provided on a front side in a mounting direction of the sheet cassette with respect to the apparatus main body. 5. The apparatus according to claim 1, wherein the height of the gap regulating member is such that the gap regulating member is located near a nip portion between a feed roller and a retard roller constituting the feeding means when the apparatus is mounted on the apparatus main body. The sheet feeding device according to claim 2. 6. The sheet feeding apparatus according to claim 2, wherein a length of the gap regulating member in a longitudinal direction is longer than a length of a roller constituting the feeding unit. 7. An image forming apparatus for forming an image on a fed sheet, the sheet feeding apparatus according to claim 1 for feeding a sheet, and the sheet feeding. An image forming apparatus, comprising: an image forming unit configured to form an image on a sheet fed by the apparatus.