JP3337806B2 - Sheet feeding apparatus and image forming apparatus - Google Patents

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 provided in an image forming apparatus such as a laser beam printer and a copying machine, and more particularly, to a method of positioning a sheet at a plurality of reference positions having different width sizes and feeding the sheet. The present invention relates to a sheet feeding device capable of feeding.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a laser beam printer, a copying machine or the like, an apparatus equipped with a multi-tray capable of manually feeding or stacking and supplying a plurality of recording papers is used. When the multi-tray is placed on the reference position, all the supposed sizes of recording paper are placed so that the device can recognize any size of recording paper as long as the paper is assumed to pass through. In order to turn off the sheet presence sensor, a detection means such as a sensor flag is provided from the reference position to the smallest recording sheet width that is assumed to pass the sheet.

[0003]

However, when a small-width recording sheet such as an envelope is sent out at a reference position (second reference) different from the original reference position (first reference), the first paper is required. If the sensor flag is arranged assuming the paper passing according to the standard, the sensor flag is rotated even when the recording paper of the size to be sent according to the second standard is sent according to the first standard. Then the sheet presence sensor is turned off. For this reason, misprinting may be caused or a means for detecting the width of the recording paper must be separately provided in order to prevent the misprinting, which may complicate the configuration and increase the manufacturing cost. is there.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus which solves the above-mentioned problems of the prior art and which is low-cost and prevents feeding of a sheet placed at an incorrect reference position. .

[0005]

A typical means for solving the problems of the prior art and applied to the embodiments described below is a sheet stacking means for stacking sheets, and the sheet stacking means includes: A first reference member and a second reference member that are respectively provided at a first reference position and a second reference position that are different positions in the width direction of the sheets to be stacked, and abut the sheet ends on the same side; Regulating means provided in the means, for positioning the other end of the sheet having one end abutted against each of the first reference member and the second reference member, the regulating means being movable in the width direction of the stacked sheets; A detecting unit for detecting the presence or absence of a sheet stacked on the sheet stacking unit; and a feeding unit for conveying a sheet supplied from the sheet stacking unit, wherein the second reference position is the second reference position. 1 The detecting unit is provided in an area between the reference position and the regulating unit, and the detecting unit sets a minimum sheet among sheets assumed to be fed using the second reference position as a reference position, in the second reference position. The second provided in the
The largest sheet out of the sheets that are assumed to be fed inside the width of the sheet when abutted against the reference member and the second reference position is assumed to be the reference position is provided at the first reference position. The sheet is provided in a region outside the width of the sheet when the sheet abuts on the first reference member.

[0006]

According to the above means, the detecting means is provided with the second
Among the sheets that are assumed to be fed with the reference position as the reference position, the smallest sheet is inside the width of the sheet when the second sheet is abutted against the second reference member provided at the second reference position, and Outer than the width of the sheet when the largest sheet of the sheets assumed to be fed using the second reference position as the reference position abuts against the first reference member provided at the first reference position. Is provided in the first reference position, a sheet having a maximum width assumed to be supplied against the second reference member provided at the second reference position is provided at the first reference position. Even if the sheet is placed on the sheet stacking means by abutting the first reference member, the detecting means cannot detect the presence of the sheet.

[0007]

【Example】

 [First Embodiment]

Hereinafter, a sheet feeding apparatus using the above means will be described with reference to the drawings. This embodiment will be described using a laser beam printer as an image forming apparatus equipped with a sheet feeding device. 1 is an explanatory perspective view of a sheet feeding device, FIGS. 2 to 5 are explanatory diagrams showing a relationship between a multi-tray and a sheet width, and FIGS. 6 and 7 show a positional relationship between a sheet size and a sheet presence / absence detection sensor. FIG. 8 is an explanatory view showing a schematic configuration of a laser beam printer.

(Overall configuration)

First, a schematic configuration of a laser beam printer will be described with reference to FIG. In FIG. 8, reference numeral 1 denotes an example of a laser beam printer provided with a sheet feeding device, and this configuration will be schematically described below.

Reference numeral 2 denotes a sheet cassette for stacking and storing a plurality of cut sheets P such as recording papers, which employs a front loading system which is mounted below the laser beam printer 1 from the front (front side in the drawing). The sheets P stacked on the sheet cassette 2 are sent out by a cassette feeding roller 3 in a direction orthogonal to the mounting direction of the sheet cassette 2. The sheet P sent out by the cassette feeding roller 3 is further conveyed further downstream by the conveying roller pair 4 and the stopped registration roller pair 5
Transported to

Reference numeral 6 denotes a multi-tray, which is openably and closably mounted on the right side of the apparatus main body. As will be described later, the multi-tray 6 supplies sheets P of various sizes by hand or in a stacked manner, and is conveyed to a registration roller pair 5 stopped by a feeding roller 7 as feeding means.

The sheet P conveyed to the pair of registration rollers 5 has its leading end abutted against a nip portion to correct skew, and thereafter, the image forming section 8 and the fixing section 9 serving as image forming means.
Is discharged through. The image forming section 8 is provided with a process cartridge 8 a which is detachable from the laser beam printer 1.
a, an electrophotographic photosensitive drum 8b as an image carrier, a charging unit 8c for charging the surface of the photosensitive drum 8b, a developing unit 8d for forming a toner image on the photosensitive drum 8b, A cleaning unit 8e and the like for removing the remaining toner are provided. The photosensitive drum 8b is provided with a scanner unit 8 according to image information.
Exposure is performed by laser light emitted from f.

The image forming section 8 includes a photosensitive drum 8
A transfer roller 8g for transferring the toner image formed on the surface of the sheet b to the sheet P is provided. The transfer roller 8g is used to transfer the sheet P conveyed by the registration roller pair 5.
Is pressed onto the photosensitive drum 8b, and the toner image on the photosensitive drum 8b is transferred to the sheet P by applying a voltage having a polarity opposite to that of the toner image to the transfer roller 8g.

The sheet P on which the toner image has been transferred by the transfer roller 8g is sent to a fixing unit 9. This fixing unit 9
Is provided with a fixing roller 9a and a pressure roller 9b, and a sheet P is provided between the fixing roller 9a and the pressure roller 9b.
When the sheet passes, heat and pressure are applied to fix the toner image on the sheet P.

As described above, the sheet P sent from the sheet cassette 2 or the multi-tray 6 is transferred with the toner image by the process cartridge 8a and the transfer roller 8g, and the transferred toner image is fixed by the fixing unit 9 to fix the upper surface of the apparatus. The paper is discharged face down (with the image surface facing down) onto the discharge tray 10 formed in the printer.

(Configuration of Sheet Feeding Apparatus)

Next, the configuration of the sheet feeding apparatus will be specifically described with reference to FIGS. As described above, the multi-tray 6 is attached to the right side of the apparatus main body so as to be openable and closable, and also serves as a part of the exterior of the apparatus main body. The multi-tray 6 is provided with a sub-tray 11 that can be extended in the length direction of the sheet P. When the sub-tray 11 is not used, it can be stored in the multi-tray 6.

On the left end side of the multi-tray 6, there is provided first reference means for defining a reference position at which a sheet end is abutted.
The reference member 12 and the second reference member 13 are provided at different positions in the width direction, respectively. The first reference member 12 is a reference position assuming a longitudinal feed of a relatively wide A4, LTR, LGL, EXE size or the like, and the second reference member 13 is a relatively narrow Monarch, COM-10. , DL size, etc., is a reference position assuming vertical feeding of each envelope. Further, the first reference member 12 is fixed to the multi-tray 6, the second reference member 13 is rotated 90 degrees and held upright / storage, and the first reference member 12 is used as a reference position. In this case, the multi-tray 6 is used by being stored in parallel. A side regulating plate 14 movable in the width direction (perpendicular to the sheet feeding direction) is provided on the right end side of the multi-tray 6.
Is provided. The side regulating plate 14 is for positioning one end of the sheet P against the first reference member 12 or the second reference member 13 and then sliding the sheet P in the width direction to position the other end.

As shown in FIG. 2, the position of the second reference member 13 is such that the side regulating plate 14 is moved to the rightmost side (at this time, the distance between the first reference member 12 and the side regulating plate 14 is 1
The largest width of the sheet P assumed to be fed with the reference member 12 as the reference position, that is, LGL
Since it is necessary to be larger than the width of the size (width 215.9 mm), the width is set to 218 mm. ), The sheet having the smallest width among the sheets P, which is assumed to be fed to the side regulating plate 14 with the first reference member 12 as a reference position, that is, a sheet of EXE size (width 184.2 mm). P
The sheet 1 is arranged so as to be on the right side from the left end of the sheet when the sheet 1 is placed against the sheet.

As shown in FIG. 1, on the downstream side of the multi-tray 6 in the sheet feeding direction, an intermediate plate 15 for pressing the sheet P against the feeding roller 7 indicated by a broken line from below is provided. And is urged toward the feed roller 7 by a spring (not shown). The rotation of the intermediate plate 15 is regulated by a cam (not shown). When the cam rotates in synchronization with a recording start signal, the leading end of the sheet supplied from the multi-tray 6 is pressed against the feed roller 7 to be moved to the uppermost position. Is configured to be sent out. The feed roller 7 is fitted on a rotary shaft 7a rotatably supported by a frame 16 of the apparatus main body, and is driven to rotate by driving means (not shown).

The frame 16 has a multi-tray 6
A sensor flag 17 which constitutes a detecting means for detecting the presence or absence of the upper sheet P is rotatably supported. The tip of the sensor flag 17 extends below the middle plate 15 through a cut hole formed in the middle plate 15 and presses the sub-sensor flag 18 shown by a broken line in FIG. If the sub sensor flag 18 is not pressed by the sensor flag 17,
It is arranged at a position where a sheet presence sensor of a photo interrupter (not shown) is shielded from light.

Here, the position of the sensor flag 17 is
As shown in FIG. 3, the sheet P2 having the smallest width among the sheets P assumed to be fed with the first reference member 12 as the reference position, that is, the sheet P2 of the EXE size (width 184.2 mm) is used as the first reference. The first reference member 12 is closer to the right end of the sheet placed against the member 12, and the sheet P is assumed to be fed with the second reference member 13 as a reference position as shown in FIG. The smallest of these, namely Mo
The right end of the sheet on which the sheet P3 of the Narch size (width 98.4 mm) is abutted against the second reference member 13 is located closer to the second reference member 13, and as shown in FIG. A sheet P4 having the largest width among sheets P assumed to be fed as a reference position, that is, a sheet P4 having a DL size (width 110 mm) is placed on the first reference member 12 on the right side of the right end of the sheet. That is, as shown in FIG. 6, 110 mm to 156.4 mm from the first reference member 12.
It is provided between.

(Sheet feeding operation)

Next, the operation of the sheet feeding apparatus will be described with reference to FIGS. First, a sheet P having a relatively wide sheet width such as A3 or LTR size, which is supposed to be fed with the first reference member 12 as a reference position, is attached to the first reference member 12 as shown in FIG. After the sheet P is placed on the multi-tray 6 and the sub-tray 11, the side regulating plate 14 is slid in the width direction to position the other end. At this time, the second reference member 13 is stored by being tilted in parallel with the multi tray 6. Also at this time the sensor flag
17 is pushed and rotated by a portion of the sheet placed on the multi-tray 6 from the center to the right from the center, and the pressed state of the sub-sensor flag 18 is released, and the sub-sensor flag 18 is released.
More away. For this reason, the sub sensor flag 18 rotates to shield the sheet presence / absence sensor of the photo interrupter (not shown), and the apparatus main body can recognize the presence of the sheet P based on the detection signal. In this state, manual feeding becomes possible, and the feed roller 7 is driven to rotate by the recording start signal to feed the sheet P, and the image is transferred and fixed in accordance with the known image forming process described above. After that, the sheet is discharged onto the discharge tray 10.

Next, as shown in FIG. 4, a sheet P whose sheet width such as an envelope size is relatively narrow and is assumed to be fed with the second reference member 13 as a reference position,
Rotate 90 degrees to stand on the multi-tray 6, abut one end on the second reference member 13, place the sheet P on the multi-tray 6 and the sub-tray 11, and slide the side regulating plate 14 in the width direction Then, the other end is positioned. At this time, the sensor flag 17 is pushed by the leading end portion of the sheet placed on the multi-tray 6 and is separated from the sub-sensor flag 18. For this reason, the sub sensor flag 18 is rotated to shield the sheet presence / absence sensor of the photo interrupter (not shown), so that the apparatus main body can recognize the presence of the sheet P. In this state, manual feeding becomes possible, and the feed roller 7 is driven to rotate by the recording start signal to feed the sheet P, and the image is transferred and fixed in accordance with the known image forming process described above. After the output tray
Exhausted on 10.

However, as shown in FIG.
When the sheet P, which is supposed to be fed with the reference member 13 as the reference position, is placed on the multi-tray 6 with the first reference member 12 as the reference position, it is moved to the second reference member 13. Even if the maximum width of the sheet P is assumed to be fed as a reference position, since the sheet width does not reach the sensor flag 17, the sheet presence / absence sensor of a photo interrupter (not shown) is not shaded, and the apparatus body is Sheet P
Cannot be recognized. Therefore, it is possible to prevent the sheet P from being placed and fed at an incorrect reference position, and to prevent erroneous printing. Further, since there is no need to separately provide a detecting means for detecting the sheet width, a low-cost and easy-to-operate sheet feeding apparatus can be provided.

As shown in FIG. 2, the first reference member
If the sheet P intended to be fed with the reference position 12 as the reference position is placed on the multi-tray 6 with the second reference member 13 as the reference position and the sheet P is to be fed, the first reference member 12
The second reference member 13 and the side regulation plate 14
It is not possible to place it between the space. For this reason, the sheet cannot be fed at a reference position different from the reference position where feeding is originally assumed.

When the laser beam printer 1 uses the first reference member 12 as a reference position, an A4, LTR size sheet P
Assuming the vertical feeding of LGL, EXE, B4, A3, and LDR size sheets P, and the vertical feeding of Monarch, COM-10, and DL size envelopes with the second reference member 13 as the reference position. 7, if the second reference member 13 is positioned 115 mm from the first reference member 12 as shown in FIG. 7, the setting area of the sensor flag 17 is 115 mm to 213.4 mm from the first reference member 12. Area.

[Second embodiment]

Next, another example of the sheet feeding apparatus will be described with reference to FIGS. 10 and 11 are cross-sectional views of the multi-tray 6 viewed from the direction of the arrow in FIG. Since the schematic configuration of the sheet feeding apparatus is the same as that of the first embodiment, the same members will be denoted by the same reference numerals, and the description will be referred to.

This embodiment is similar to the first embodiment, except that the first
Instead of providing the second reference member 13 in addition to the reference member 12,
A reference member that defines a reference position at the left end of the multi-tray 6
19 is provided slidably in the width direction. This reference member 19 is a spring provided on the back side of the multi tray 6 as shown in FIG.
20 is used to strike the first reference position. In the lower part of the reference member 19, a claw 19a is protruded, and grooves formed at the first reference position and the second reference position of the multi-tray 6, respectively.
Engage with 21a, 21b. In the first reference position, the reference member 19 is held with the claw 19a engaged with the groove 21a.
Further, as shown in FIG. 11, when the reference member 19 is moved to the second reference position, the claw 19a is held by engaging with the groove 21b. A side regulating plate 14 movable in the width direction (perpendicular to the sheet feeding direction) is provided on the right end side of the multi-tray 6.
Is provided. The first reference position, the second reference position,
The positional relationship of the sensor flag 17 and the like is the same as in the first embodiment, and a description thereof will be omitted.

According to the above-described structure, the reference member 19 is formed into the grooves 21 with the claws 19a formed at the first reference position and the second reference position, respectively.
Since the sheet P is positioned by engaging with any one of the a and 21b, two reference members are not formed at the same time on the multi-tray 6, and the positional relationship of the sensor flag 17 and the like is the same as in the first embodiment. In addition, since feeding at an incorrect reference position cannot be performed, operability can be further improved.

[Third Embodiment]

Next, another example of the sheet feeding apparatus will be described.
This will be described with reference to FIGS. Since the schematic configuration of the sheet feeding apparatus is the same as that of the first embodiment, the same members will be denoted by the same reference numerals, and the description will be referred to.

In this embodiment, similarly to the first embodiment, a first reference member 22 and a second reference member 23 for defining a first reference position and a second reference position are provided at the left end of the multi-tray 6, respectively. The second reference member 23 is rotatably attached to the multi-tray 6 by being mounted to be rotatable by 90 degrees. Since the setting area of the sensor flag 17 and the like is the same as in the first and second embodiments, the sheet P cannot be fed at an incorrect reference position.

The rotating end of the second reference member 23 has a cam 23
The cam 23a is connected to the other end of the spring 24 whose one end is connected to the multi-tray 6, and the second reference member 23 falls down on the multi-tray 6 as shown in FIG. It is urged to be in a state. A slide bar 25 is formed in a portion of the side regulating plate 14 having an L-shaped cross section parallel to the multi-tray 6, and the side regulating plate 14 is moved toward the center of the multi-tray 6 as shown in FIG. Then, the tip of the slide bar 25 abuts on the cam 23a, and rotates the second reference member 23 by 90 degrees against the elastic force of the spring 24 to stand on the multi-tray 6.

Accordingly, when the side regulating plate 14 approaches the first reference member 22 from the width of the sheet P which is assumed to be fed with the first reference member 22 as the reference position, the second reference member
By setting the length of the slide bar 25 so that the stand 23 stands up, it is possible not only to prevent the sheet P from being placed at the wrong reference position and to feed the sheet P, but also to go one step further and move the second reference member 23 Can be prevented from being forgotten to set up.

In each of the embodiments described above, a laser beam printer is used as an image forming apparatus equipped with a sheet feeding apparatus. However, the present invention is not limited to this, and other apparatuses such as a copying machine, It may be a printer, a facsimile or the like.

[0040]

According to the present invention, as described above, the detecting means is provided at the second reference position with the smallest sheet among the sheets assumed to be fed with the second reference position as the reference position. The largest sheet among the sheets which are assumed to be fed inside the width of the sheet when the sheet is abutted against the second reference member and the second reference position is assumed to be the reference position is the first reference. The second reference position provided at the second reference position is provided in a region outside the width of the sheet when the sheet abuts against the first reference member provided at the position.
Even if the sheet having the maximum width which is assumed to be fed against the reference member is placed on the sheet stacking means while hitting the first reference member provided at the first reference position, Cannot detect the presence of a sheet.

Therefore, it is possible to prevent a sheet from being placed and fed at an incorrect reference position, and to prevent erroneous printing. Further, since there is no need to separately provide a detecting means for detecting the sheet width, a low-cost and easy-to-operate sheet feeding apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of a sheet feeding apparatus according to a first embodiment.

FIG. 2 is an explanatory diagram showing a relationship between a multi-tray and a sheet width.

FIG. 3 is an explanatory diagram illustrating a relationship between a multi-tray and a sheet width.

FIG. 4 is an explanatory diagram illustrating a relationship between a multi-tray and a sheet width.

FIG. 5 is an explanatory diagram illustrating a relationship between a multi-tray and a sheet width.

FIG. 6 is an explanatory diagram illustrating a positional relationship between a sheet size and a sheet presence / absence detection sensor.

FIG. 7 is an explanatory diagram illustrating a positional relationship between a sheet size and a sheet presence / absence detection sensor.

FIG. 8 is an explanatory diagram illustrating a schematic configuration of a laser beam printer.

FIG. 9 is an explanatory perspective view of a sheet feeding apparatus according to a second embodiment.

FIG. 10 is an explanatory sectional view of a multi-tray.

FIG. 11 is an explanatory sectional view of a multi-tray.

FIG. 12 is an explanatory sectional view of a multi-tray according to a third embodiment.

FIG. 13 is an explanatory sectional view of a multi-tray.

[Explanation of symbols]

 P ... Sheet 1 ... Laser beam printer 2 ... Sheet cassette 3 ... Sending roller 4 ... Conveying roller pair 5 ... Registration roller pair 6 ... Multi tray 7 ... Sending roller 7a ... Rotating shaft 8 ... Image forming unit 8a ... Process cartridge 8b ... photosensitive drum 8c ... charging means 8d ... developing means 8e ... cleaning means 8f ... scanner section 8g ... transfer roller 9 ... fixing section 9a ... fixing roller 9b ... pressure roller 10 ... discharge tray 11 ... sub-tray 12, 22 ... first reference Members 13, 23: Second reference member 14: Side regulating plate 15: Middle plate 16: Frame 17: Sensor flag 18: Sub-sensor flag 19: Reference member 20, 24: Spring 21a, 21b: Groove 23a: Cam 25: Slide bar

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Asano 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Tomio Noguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 1/00-3/68 B65H ^7/ 00-7/20 B65H 11/00-11/02

Claims (4)

(57) [Claims] 1. A sheet stacking means for stacking sheets, wherein the sheet stacking means is provided at a first reference position and a second reference position which are different positions in the width direction of the sheets to be stacked, and is provided on the same side. A first reference member and a second reference member for abutting the end of the sheet, and the other end of the sheet provided on the sheet stacking means and having one end abutting on each of the first reference member and the second reference member Regulating means capable of moving in the width direction of the sheets to be stacked, detecting means for detecting the presence or absence of sheets stacked on the sheet stacking means, and sheets supplied from the sheet stacking means The second reference position is provided in an area between the first reference position and the regulating unit, and the detection unit is based on the second reference position. Rank Inside the width of the sheet when the smallest sheet of the sheets supposed to be fed as the sheet is abutted against the second reference member provided at the second reference position, and In a region outside the width of the sheet when the largest sheet of the sheets assumed to be fed with the reference position as the reference position is abutted against the first reference member provided at the first reference position. A sheet feeding device, which is provided. 2. A sheet stacking means for stacking sheets, the first reference position being provided on the sheet stacking means, wherein the first reference position and the first reference position are different positions in a width direction of the stacked sheets. A reference member movable to a second reference position and abutting the sheet end on the same side; and one end abutting on each of the first reference member and the second reference member provided on the sheet stacking means. Regulating means movable in the width direction of the stacked sheets to position the other end of the stacked sheets, detecting means for detecting the presence or absence of the sheets stacked on the sheet stacking means, and the sheet stacking means Feeding means for conveying the supplied sheet, wherein the second reference position is provided in an area between the first reference position and the regulating means, Of the sheets that are assumed to be fed with the second reference position as the reference position, the smallest sheet is inside the width of the sheet when the sheet abuts against the reference member moved to the second reference position, and In the area outside the width of the sheet when the largest sheet of the sheets that are assumed to be fed with the second reference position as the reference position is abutted against the reference member moved to the first reference position. A sheet feeding device, which is provided. 3. The apparatus according to claim 2, wherein the second reference position is configured such that the restricting means moves the first reference position and the second reference position in a sheet width direction.
In a state where the sheet is moved to the most opposite side from the reference position, one end of a sheet having the smallest width among the sheets to be fed using the first reference position as the reference position is pushed to the regulating means. The sheet feeding device according to claim 1, wherein the sheet feeding device is arranged so as to be closer to the regulating unit than the other end of the sheet feeding device. 4. A sheet feeding device according to claim 1, further comprising: an image forming unit configured to form an image on a sheet supplied from the sheet feeding device in accordance with image information. An image forming apparatus comprising: