JP3257899B2 - Sheet conveying device and image forming device - 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 conveying apparatus provided in an image forming apparatus such as a copying machine, a laser beam printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a switching means for switching a sheet conveying path such as a flapper is provided in a sheet conveying path leading to image formation and further, a sheet after image fixing to a discharge section. In the case of double-sided or multiple image formation, the sheet is turned upside down to be stacked on an intermediate tray by being guided to a reversing unit, or in the case of single-sided image formation, the sheet is turned upside down by the above-described switching means and face down. (With the image side facing down), the pages are aligned and discharged onto a discharge tray outside the apparatus.

[0003]

However, in the above-mentioned conventional copiers and the like, if the sheet after the image formation is discharged and left on the discharge tray, the sheet is face-up (the image surface is turned upward). When the paper is ejected, it is easy to touch other people's eyes.Even if the sheet is ejected face down, there is a risk of touching the eyes of others, and if the print contents are important such as confidential documents, Confidentiality cannot be maintained.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to add a sheet folding function in addition to a sheet reversing and conveying function, thereby maintaining document confidentiality and realizing a multifunctional apparatus. It is to provide a device.

[0005]

SUMMARY OF THE INVENTION The problems of the prior art are solved.
Representative means applied to the embodiments described below
Are a first and a third for conveying a sheet in a substantially horizontal direction.
Conveying means, and a sheet conveyed by the first conveying means
Driven in a forward and reverse direction for transporting
Enclosed by the conveying means and the first, second and third conveying means
Switching means for switching the sheet conveying path in the area,
The sheet conveying path length between the first and third conveying means is L₁,Previous
The length of the sheet conveying path between the first and second conveying means is L_TwoAnd said
The sheet conveying path length between the second and third conveying means is L_Three, Sheet
Length is L_PThen, L₁, L_Two, L _Three> L_P/ 2
The switching means is adapted to switch the sheet conveying path
Hand to change the front and back of the sheet by changing the ring
Step and folding means for folding the sheet from a predetermined position
And is also used.

[0006]

According to the above-mentioned means, when the sheet is reversely conveyed, the sheet conveyed by the first conveying means is guided to the second conveying means by the switching means, and the second conveying means is driven to rotate forward to convey the sheet. Carry a predetermined amount. Next, the sheet transport path is switched by the switching unit and the second transport unit is driven to rotate in the reverse direction, and the sheet is turned upside down and transported to the third transport unit.

When the sheet is folded and conveyed,
The sheet conveyed by the first conveying unit is guided to the second conveying unit by the switching unit, and the second conveying unit is driven to rotate forward to move the switching unit at a predetermined timing while the sheet passes through the switching unit. To switch the sheet conveyance path. At this time, the sheet is creased from a predetermined position by the switching means, and at the same time, the sheet is conveyed from the fold side by reversely driving the second conveying means, and is completely bent when passing through the third conveying means. It is transported downstream in the state.

[0008]

【Example】

Hereinafter, an embodiment of an image forming apparatus according to the present invention to which the above-described means is applied will be described with reference to the drawings. In this embodiment, an embodiment using a color copying machine capable of double-sided recording as an image forming apparatus will be described. 1 is an explanatory diagram showing a process of folding and conveying a sheet, FIG. 2 is an explanatory diagram of a folded sheet, FIG. 3 is an explanatory diagram showing a process of reversing and conveying a sheet, and FIG. 4 is an explanatory diagram showing a schematic configuration of a copying machine. It is.

First, a schematic configuration of a copying machine will be described with reference to FIG. The copying machine has a digital image reader section at the top of the apparatus and a digital image printer section at the bottom of the apparatus as image forming means. In the digital image reader unit, the original 1 is placed on an original platen glass 2 and is exposed and scanned by an exposure lamp 3 so that a reflected light image 4 from the original 1 is mirrored 5 a, 5 b, 5 c and a lens 6. Via CC
The light is condensed on the image reading element 7 such as D to obtain an image signal. This image signal is processed by a video processing unit (not shown) via an amplification circuit (not shown) and transferred to a digital image printer unit.

In the above digital image printer section, a photosensitive drum 8 as an image carrier is rotatably held, and a pre-exposure lamp 9, a primary charger 10, a laser exposure optical system 11, Developing device 12, transfer charger 1
3, a cleaning device 14 is provided.

In the laser exposure optical system 11, an image signal from the digital image reader section is converted into an optical signal by a laser output section, and the converted laser light is reflected by a polygon mirror 11a. The light is projected on the peripheral surface of the photosensitive drum 8 via 11c. During image formation, the photosensitive drum 8 is rotated in the
The photosensitive drum 8 after the charge is removed is uniformly charged by the primary charger 10 and irradiated with the light image 4 from the original surface to form an electrostatic latent image. Next, the latent image on the photosensitive drum 8 is developed by the developing device 12 to form a toner image on the photosensitive drum 8 using a resin as a base.

The sheet P sent from the sheet cassettes 16, 17, 18 and 19 by the pickup rollers 20, 21, 22 and 23 is reduced by one pair of retard rollers 24, 25, 26 and 27 to one sheet.
The sheets are separated and conveyed one by one, conveyed in the direction of arrow Q, and conveyed to the stopped registration roller pair 28 to correct the skew.
The sheet P sent from the multi-tray 15 is similarly conveyed to the stopped registration roller pair 28 to correct the skew. The sheet P is conveyed between the transfer charger 13 and the photosensitive drum 8 at a predetermined timing by driving the registration roller pair 28, and a voltage having a polarity opposite to that of the toner image is applied by the transfer charger 13. The toner image on the photosensitive drum 8 is transferred to the sheet P. The toner remaining on the drum surface after image transfer is removed by the cleaning device 14 to prepare for the next image formation.

The sheet P to which the image has been transferred is neutralized by a static elimination needle 28a, separated from the drum surface, and conveyed to a fixing device 30 by a conveying device 29. When the sheet P passes through the fixing device 30, heat and pressure are applied to fix the transferred image.

The sheet P on which the image has been fixed is transferred to a sheet conveying device.
In the case of image formation on only one side by 39, the image is turned upside down and discharged face-down to the outside of the apparatus, and in the case of image formation on both sides, it is transported to the reversing unit 52 and turned over. , 33, and 34 are opened and closed to discharge and stack on the intermediate tray 35 with the image side up. The sheets P stacked on the intermediate tray 35 are sent out by a sweeping roller 36 and a pick-up roller 37, separated and conveyed one by one in a direction indicated by an arrow R by a pair of retard rollers 38, and at a predetermined timing by the pair of registration rollers 28 described above. At the transfer unit,
After the double-sided image formation is performed, the sheet is discharged out of the apparatus.

Next, the configuration of the sheet conveying device 39 will be described with reference to FIG. In FIG. 1A, 40a,
Reference numeral 40b denotes a first conveying roller pair, which is a first conveying means, and conveys the sheet P after image fixing in a substantially horizontal direction (the direction of arrow H). Reference numerals 41a and 41b denote second conveying roller pairs as second conveying means, which are driven forward and reverse by a driving source (not shown) to move the sheet P in a substantially vertical direction (I direction or J direction).
Transport to Reference numerals 42a and 42b denote a third conveying roller pair as a third conveying means. The sheet P conveyed by the first conveying roller pair 40a, 40b or the second conveying roller pair 41a, 41b is moved substantially horizontally (arrow K). (In the direction). 43, 44, and 45 are sheet conveyance guides, and the first, second, and third conveyance roller pairs 40a, 40b, 41a, 41b,
A sheet conveyance path is formed between 42a and 42b.

Reference numerals 46, 47 denote flapper as switching means, and the first, second, and third pairs of transport rollers 40a, 40b, 41
a, 41b, 42a, and 42b. The flappers 46 and 47 transfer the sheet P transported by the first transport roller pair 40a and 40b to the second transport roller pair 41a and 41b or the third transport roller pair 42a and 42.
The sheet transport path is switched to b. The flapper 46 rotates about a rotation center 46a, and the flapper 47
Drives at the same distance as 46. One end of the flapper 46 is connected to a solenoid 48, and the ON / OFF control of the solenoid 48 causes the flappers 46 and 47 to rotate. A flapper return spring 49 is connected to the flapper 46, and constantly urges the flapper 46 clockwise about a rotation center 46a.

Reference numeral 50 denotes a sheet detection sensor for detecting a sheet end, which is provided on the upstream side in the sheet conveyance direction from the first conveyance roller pair 40a, 40b.
The first transport roller pair 40a, 40b
, And switching between forward and reverse rotation of the second transport roller pair 41a and 41b.

The length of the sheet transport path between the first and third transport roller pairs is L ₁ , the length of the sheet transport path between the first and second transport roller pairs is L ₂ , and the second and third transport rollers are Assuming that the length of the sheet conveying path between the pair is L ₃ and the length of the sheet of the minimum size to be folded in two is L _P , the relationship is L ₁ , L ₂ , L ₃ > L _P / 2.

Next, the process of folding and conveying a sheet will be described with reference to FIG. As shown in FIG.
When the leading end of the sheet P conveyed in the arrow H direction is detected by the sheet detection sensor 50, the first conveying roller pair 40
a and 40b rotate in the direction of arrow A in the figure. At this time, the solenoid 48 is in the ON state, and the flappers 46 and 47 are at the positions shown in FIG. 1A rotated counterclockwise. Sheet P
Are transported by the first transport roller pair 40a, 40b and pass between the flappers 46, 47, and the second transport roller pair 41a, 41
b. The driving of the second conveying roller pair 41a, 41b is stopped, and after a lapse of a predetermined time after the sheet detection sensor 50 detects the front end of the sheet, the front end of the sheet strikes the nip to form a loop and correct skew. After that, arrow B
Rotate in the direction.

The second pair of transport rollers 41a, 41b is the same as that shown in FIG.
As shown in (b), the sheet P is transported in the direction of arrow I. The fold position of the sheet P (for example, the position of L _P / 2 for a half of the sheet P) is determined by the flapper 47 while counting the conveyance amount after the sheet detection sensor 50 detects the leading end of the sheet by a clock or the like (not shown). When passing through the bent end 47a, the solenoid 48 is turned off, and the flappers 46, 47 are rotated clockwise around the rotation center 46a by the flapper return spring 49 as shown in FIG. At this time, the second conveying roller pair 41a, 41b is reversed and rotated in the direction of arrow C to convey the sheet P in the direction of arrow J toward the third conveying roller pair 42a, 42b. At this time, the sheet P is moved by the bent end 47a of the flapper 47 to the second position.
The paper is conveyed in a state where the fold is formed.

Then, as shown in FIG. 1 (d), the sheet P is nipped by third conveying roller pairs 42a and 42b rotating in the direction of arrow D from the fold side, and is conveyed in a completely folded state. The sheet P is folded in the two-fold state as shown in FIG.
Is transported in the direction of arrow K and discharged out of the apparatus.

FIG. 2 shows a state where the sheet P is folded.
2A, the sheet P1 is bent so that the image surface becomes the cover, and FIG. 2B is bent so that the image surface becomes the inside. FIG. 2B shows a case where a destination such as a facsimile is located near the front end of the sheet and the content of the description is a confidential sentence or the like, only the destination is put on the front surface (at this time, the sheet P is shifted by ΔL and folded), and the remaining Can be stapled in the inside of a bend, and can be applied to the multifunctionalization of the apparatus and the confidentiality of the written contents.

In FIGS. 2A and 2B, it is necessary to convey the sheet P after forming the image upside down, and this process will be described below with reference to FIG. The sheet P after image formation is guided to a paper discharge vertical path 51 shown in FIG.
In the reversing section 52, the sheet is reversed and conveyed in the order of arrows M → N → O, and is discharged and stacked on the intermediate tray 35 with the image surface facing upward. Thereafter, the sheet P is re-fed and guided again to the image forming unit, where no image is formed or "important" or "secret".
After the image of the stamp is transferred, the transferred image is fixed, transported to the first transport roller pair 40a, 40b from the direction of arrow H shown in FIG. 1A, and discharged through the above-described bending process. The state is bent as shown in FIG.

Next, the reversing discharge (face down) operation of the sheet conveying device 39 will be described with reference to FIG.
As shown in FIG. 3A, the sheet P on which the image has been fixed is conveyed in the direction of arrow H, and when the leading end is detected by the sheet detection sensor 50, the first conveying roller pair 40a, 40b moves to the arrow A in the figure. Rotate in the direction. At this time, the solenoid 48 is in the ON state, and the flappers 46 and 47 are at the positions shown in FIG. The sheet P is transported by the first transport roller pair 40a, 40b, and is guided to the second transport roller pair 41a, 41b via the flapper 46,47. Next, the sheet P is rotated in the direction of arrow B by a second pair of conveying rollers 41a,
When the sheet is conveyed in the direction of arrow I by arrow 41b and a predetermined time has passed since the sheet detection sensor 50 detected the sheet rear end, that is, when the sheet rear end passed the bent end 47a of the flapper 47, the second conveyance roller pair As shown in FIG. 3B, the sheets 41a and 41b are reversely driven in the direction of arrow C, and the sheet P is conveyed in the direction of arrow J. At this time, the solenoid 48 is turned off.
Then, the flappers 46 and 47 are rotated clockwise about the rotation center 46a by the flapper return spring 49. Therefore, the sheet P is conveyed to the third pair of conveying rollers 42a and 42b while being guided by the flapper 47 by the pair of second conveying rollers 41a and 41b. Then, as shown in FIG. 3C, the sheet P is conveyed in the direction of arrow K by the third pair of conveying rollers 42a and 42b rotating in the direction of arrow D, and is discharged face-down outside the apparatus.

According to the above configuration, the flappers 46 and 47 provided in the sheet conveying device 39 change the timing of switching the sheet conveying path, thereby turning over the sheet P and reversing the sheet P. By also using the bending means for bending from the position, a security function can be added to the copying machine in addition to the face-down transport function, and the unit can be multifunctional.

Although the present embodiment has been described using a copying machine as an image forming apparatus, the present invention is not limited to this. For example, a facsimile machine, a laser beam printer, or a copying machine, a facsimile, A multifunction device such as a printer may be used.

[0028]

As described above, according to the present invention, the switching means provided in the sheet conveying apparatus includes a reversing means for changing the timing of switching the sheet conveying path so as to switch the front and back of the sheet, and By also using the folding means for bending the sheet, the image forming apparatus equipped with the sheet conveying apparatus can be provided with a security maintaining function in addition to the face-down conveying function, so that the unit can be made multifunctional.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a process of folding and conveying a sheet.

FIG. 2 is an explanatory diagram of a folded sheet.

FIG. 3 is an explanatory diagram illustrating a process of reversing and conveying a sheet.

FIG. 4 is an explanatory diagram showing a schematic configuration of a copying machine.

[Explanation of symbols]

 P: Sheet 1: Document 2: Document table glass 3: Exposure lamp 4: Reflected light image 5a, 5b, 5c, 11b, 11c: Mirror 6: Lens 7: Image reading element 8: Photosensitive drum 9: Pre-exposure lamp 10: Primary charger 11 ... Laser exposure optical system 11a ... Polygon mirror 12 ... Developer 13 ... Transfer charger 14 ... Cleaner 15 ... Multi-tray 16,17,18,19 ... Sheet cassette 20,21,22,23,37 ... Pickup rollers 24, 25, 26, 27, 38: retard roller pair 28: registration roller pair 28a: static elimination needle 29 ... transport device 30: fixing device 31, 32, 33, 34, 46, 47 ... flapper 35 ... intermediate tray 36 ... Sweeping roller 39 ... Sheet conveying device 40a, 40b ... First conveying roller pair 41a, 41b ... Second conveying roller pair 42a, 42a ... Third conveying roller pair 43, 44, 45 ... Sheet conveying guide 46a ... Rotation center 47a … Bend end 48… Solenoid 49… Flapper Return spring 50… Sheet detection sensor 51… Discharge vertical path 52… Reversing part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 45/16 B65H 37/06 G03G 15/00 530 H04N 1/00 108 H04N 1/44 B65H 29/60

Claims (3)

(57) [Claims] 1. A first and third conveying means for conveying a sheet in a substantially horizontal direction, and a second forward-reverse driven second conveying means for conveying a sheet conveyed by the first conveying means in a substantially vertical direction. A conveying unit; and a switching unit for switching a sheet conveying path in a region surrounded by the first, second, and third conveying units. The sheet conveying path length between the first and third conveying units is set to L _1. If the length of the sheet transport path between the first and second transport means is L ₂ , the length of the sheet transport path between the second and third transport means is L ₃ , and the sheet length is L _P , L ₁ and L ₂ , L ₃ > L _P / 2, and the switching means includes a reversing means for switching the front and back of the sheet by changing a switching timing of the sheet conveying path, and a folding means for bending the sheet from a predetermined position. A sheet conveying device that is also used. 2. The sheet conveying apparatus according to claim 1, wherein the switching unit is controlled to switch the sheet conveying path by a solenoid based on a detection signal of a sheet detecting unit provided in the sheet conveying path. 3. An image forming means for forming an image on a sheet in accordance with image information, and the sheet conveying device according to claim 1 for conveying the sheet after image formation. Image forming apparatus.