JP3467261B2 - Paper transport 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 for pressing a first rotating body and a second rotating body against each other to form a nip portion, and gripping and conveying a sheet at the nip portion. is there.

[0002]

2. Description of the Related Art Conventionally, for example, a conveyance path for conveying a sheet (sheet) fed from a sheet feeder in an image forming apparatus to an image forming section or a sheet on which an image is formed in the image forming section is discharged. As a sheet (sheet) conveying apparatus in a conveying path for conveying a sheet to a sheet, a sheet conveying apparatus is used that sequentially conveys sheets while gripping (sandwiching) the sheets between nip of a pair of rotating bodies (rollers).

In this sheet conveying device, stable sheet conveying property is required regardless of the type of the sheet to be conveyed, and also as the sheet conveying device, there is no mechanical variation due to the pressing force of the roller for each device. I have to

If the sheet conveyance is not stable,
The timing at which the image is sent to the image forming unit varies from sheet to sheet, and the image formation position on the sheet may change slightly each time. Further, in terms of service work, it is required that the roller can be removed from the apparatus frame as easily as possible in order to replace the roller part or clean the roller.

As a conventional roller pressure contact mechanism,
There is one such as that described in JP-A-6-27754. In the pressure contact mechanism for pressing the first roller to the second roller in this publication, springs are bridged in an arch shape with respect to the rotary shaft of both ends of the rotary shaft of the first roller. Thus, the first roller is brought into pressure contact with the second roller.

Further, the pressure contact mechanism for pressing the second roller against the first roller contacts the side surface of the bearing support portion for rotatably supporting the rotation shaft at both ends of the rotation shaft of the second roller. In some cases, this bearing support portion is pressed against the first roller side by a spring.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the first roller pressure contact mechanism of Japanese Patent Laid-Open No. 54-54, since a spring is simply stretched over the peripheral surface of the rotation shaft of the first roller, the first roller is pressed against the second roller. There is a possibility that the force may vary and a predetermined pressure contact force may not be obtained. Moreover, the spring must be removed when the first roller is replaced or removed during service work. Was causing problems such as the fall of the.

If the second roller pressure contact mechanism is used,
When removing the second roller, the second roller cannot be removed unless the pressing force of the spring is released and the bearing support part and the spring are also removed from the device. In addition to being complicated, there is a problem of loss of parts such as the spring or the bearing support portion.

The present invention has been made in view of the above problems, and a stable pressure contact force is obtained by pulling the first rotating body from a position sandwiching the second rotating body and bringing the first rotating body into pressure contact with the second rotating body. The purpose is to obtain.

[0010]

In order to achieve the above-mentioned object, the conveying apparatus of the present invention forms a nip portion by pressing the first rotating body and the second rotating body against each other, and the nip portion is formed. In a paper transport device that grips and transports paper at
A pressure contacting means for pulling the first rotating body from a position sandwiched by the second rotating body to bring it into pressure contact with the second rotating body is provided, and the rotating shaft of the first rotating body is inserted into the pressure contacting means. A rotating body support having an insertion hole for rotatably supporting the rotating shaft, and an urging body having one end attached to the rotating body support and the other end attached to the apparatus body side, The rotary body support is slidably engaged with the device frame in a direction in which the first rotary body is pressed against the second rotary body, and the rotary shaft of the second rotary body is loosely inserted therein. It is characterized in that a hole is provided.

Further, the rotating body support is a long hole in which the rotation shaft of the second rotating body is loosely inserted, and the hole has a length larger than the sliding amount of the rotating body support to the apparatus frame. That will be convenient.

In the transport apparatus having the above-mentioned structure, the rotary body support is slidably engaged with the apparatus frame in a direction in which the first rotary body is pressed against the second rotary body, and the second rotary body is slidable. It is also possible to form a curved arm that bypasses the rotation axis of the rotating body.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An outline of an image forming apparatus of the present invention will be described with reference to FIG. FIG. 1 is a front sectional view showing a configuration of a digital color copying machine which is an image forming apparatus of the present invention. On the upper surface of the copying machine body 1, a document table 11
1 and an operation panel, and the image reading unit 110 and the image forming unit 210 are provided inside the copying machine main body 1.

The upper surface of the document table 111 is supported in an openable and closable manner with respect to the document table 111, and the double-sided automatic document feeder (R) has a predetermined positional relationship with the surface of the document table 111.
ADF: Recirculating Automatic Document Fe
eder) 112 is attached.

Further, the RADF 112 first conveys the document so that one side of the document faces the image reading section 110 at a predetermined position of the document table 111, and after the image reading on this one side is completed, the other side is conveyed. The original is inverted so that its surface faces the image reading unit 110 at a predetermined position of the original table 111 and is conveyed toward the original table 111. Then, the RADF 112 discharges this document after the image reading on both sides of one document is completed, and executes the double-sided conveyance operation for the next document. The above-described operations of conveying the document and inverting the front and back are controlled in relation to the operation of the entire copying machine.

The image reading unit 110 is arranged below the document table 111 in order to read the image of the document conveyed onto the document table 111 by the RADF 112. The image reading unit 110 includes an original scanning body that reciprocates in parallel along the lower surface of the original table 111, an optical lens 115, and a CCD line sensor 116 that is a photoelectric conversion element.

This original scanning body is composed of a first scanning unit 11
3 and the second scanning unit 114. The first scanning unit 113 has an exposure lamp that exposes the image surface of the original document and a first mirror that deflects the reflected light image from the original document in a predetermined direction. While reciprocating, it reciprocates in parallel at a predetermined scanning speed. The second scanning unit 114 has a first
The first scanning unit 113 includes second and third mirrors that further deflect the reflected light image from the document deflected by the first mirror of the scanning unit 113 in a predetermined direction.
And reciprocate in parallel while maintaining a constant speed relationship.

The optical lens 115 is used in the second scanning unit 1
The reflected light image from the document deflected by the third mirror 14 is reduced, and the reduced light image is reflected by the CCD line sensor 116.
The image is formed at a predetermined position above.

The CCD line sensor 116 sequentially photoelectrically converts the formed optical image and outputs it as an electric signal. The CCD line sensor 116 is a three-line color CCD capable of reading a black-and-white image or a color image and outputting line data that is color-separated into R (red), G (green), and B (blue) color components. . The document image information converted into an electric signal by the CCD line sensor 116 is further transferred to an image processing unit (not shown) and subjected to predetermined image data processing.

Next, the configuration of the image forming section 210 and the configuration of each section related to the image forming section 210 will be described.

Below the image forming section 210, there is provided a sheet feeding mechanism 211 for separating the sheets (recording media) P stacked and accommodated in the sheet tray one by one and feeding them toward the image forming section 210. ing. The timings of the sheets P that have been separated and supplied one by one are controlled by a pair of registration rollers 212 disposed in front of the image forming unit 210, and the image forming unit 210 is imaged at the same timing as the image forming of the image forming unit 210. Is re-supplied and transported.

A transfer / conveying belt mechanism 213 is arranged below the image forming section 210. The transfer / transport belt mechanism 213 includes a driving roller 214 and a driven roller 215.
The sheet P is electrostatically attracted to and conveyed by the transfer and conveyance belt 216 stretched so as to extend substantially parallel to and between the sheet and the sheet. A pattern image detection unit is provided near the lower side of the transfer / transport belt 216.

Further, on the downstream side of the transfer / transport belt mechanism 213 in the paper transport path, a fixing device 217 for fixing the toner image transferred and formed on the paper P onto the paper P.
Are arranged. The sheet P that has passed through the nip between the pair of fixing rollers of the fixing device 217 is discharged by the discharge roller 219 onto the discharge tray 220 attached to the outer wall of the copying machine body 1 via the transfer direction switching gate 218. It

The switching gate 218 is used for the sheet P after fixing.
Is selectively switched between a path for discharging the paper P to the copying machine main body 1 and a path for re-supplying the paper P toward the image forming unit 210. The sheet P whose conveyance direction has been switched again toward the image forming unit 210 by the switching gate 218 is turned upside down via the switchback conveyance path 221 and then the image forming unit 210.
Is supplied again to.

Further, above the transfer / transport belt 216 in the image forming section 210, in the vicinity of the transfer / transport belt 216, the first image forming station Pa, the second image forming station Pb, the third image forming station Pc, and the third image forming station Pc. The four image forming stations Pd are arranged in parallel in order from the upstream side of the paper transport path.

The transfer / transport belt 216 is driven by a driving roller 214.
1 grips the paper P that is frictionally driven in the direction indicated by the arrow Z in FIG. 1 and is fed through the paper feed mechanism 211 as described above, and the paper P is transferred to the image forming stations Pa.
It is sequentially transported to Pd.

The image forming stations Pa to Pd have substantially the same structure. Each of the image forming stations Pa, Pb, Pc, Pd is a photosensitive drum 222a, 222b, 22 which is rotationally driven in the direction of arrow F shown in FIG.
2c and 222d, respectively.

Around the photosensitive drums 222a to 222d, chargers 223a, 223b, 223c, and 223d that uniformly charge the photosensitive drums 222a to 222d, respectively.
And developing devices 224a, 224b, 2 for developing the electrostatic latent images formed on the photoconductor drums 222a to 222d, respectively.
24c and 224d, and the developed photosensitive drum 222a
To 222d, transfer dischargers 225a, 225b, 225c and 225d, and cleaning devices 226a, 226b, 226c and 2 for removing toner remaining on the photosensitive drums 222a to 222d.
26d are sequentially arranged along the rotation direction of the photosensitive drums 222a to 222d.

Further, each of the photosensitive drums 222a to 222d
Above the above is a laser beam scanner unit (LSU)
227a, 227b, 227c and 227d are provided respectively. The LSUs 227a to 227d include a semiconductor laser element (not shown) that emits dot light modulated according to image data, and a polygon mirror (deflecting device) 240 for deflecting the laser beam from the semiconductor laser element in the main scanning direction. And an fθ lens 241 and a mirror 24 for forming an image of the laser beam deflected by the polygon mirror 240 on the surfaces of the photoconductor drums 222a to 222d.
2, 243 and the like.

LSU 227a stores a pixel signal corresponding to a black component image of a color original image, and LSU 227b stores a pixel signal corresponding to a cyan color component image of a color original image.
A pixel signal corresponding to the magenta color component image of the color original image is input to the SU 227c, and a pixel signal corresponding to the yellow color component image of the color original image is input to the LSU 227d.

As a result, the electrostatic latent images corresponding to the color-converted original image information are converted into the respective photosensitive drums 222a to 222d.
Formed on. Then, the developing device 224a contains black toner, and the developing device 224b contains cyan toner.
The developing device 224c contains magenta toner and the developing device 224d contains yellow toner. The electrostatic latent images on the photosensitive drums 222a to 222d are
It is developed with toner of each of these colors. As a result, the document image information color-converted by the image forming unit 210 is reproduced as a toner image of each color.

Further, a paper suction (brush) charger 2 is provided between the first image forming station Pa and the paper feed mechanism 211.
28 is provided, and the paper adsorption charger 228 charges the surface of the transfer / conveying belt 216, and the paper feeding mechanism 21.
The sheet P supplied from the first sheet forming apparatus 1 is securely sucked onto the transfer / conveying belt 216 and is fed to the first image forming station Pa.
To the fourth image forming station Pd without any deviation.

On the other hand, between the fourth image forming station Pd and the fixing device 217, a static eliminator (not shown) is provided just above the drive roller 214. An AC current for separating the paper P electrostatically attracted to the transfer / transport belt 216 from the transfer / transport belt 216 is applied to the static eliminator.

In the digital color copying machine having the above-mentioned structure, a cut sheet of paper is used as the paper P. This paper P is sent out from the paper feed cassette and fed by the paper feed mechanism 2.
When the sheet P is fed into the guide of the sheet feeding / conveying path 11, the front end portion of the sheet P is detected by a sensor (not shown), and the pair of registration rollers 212 is detected based on the detection signal output from the sensor. Is temporarily stopped by.

Then, the paper P is sent on the transfer / conveying belt 216 rotating in the direction of arrow Z in FIG. 1 at a timing with each of the image forming stations Pa to Pd. At this time, since the transfer / conveying belt 216 is charged by the sheet adsorbing charger 228 as described above,
The sheet P is stably conveyed and supplied while passing through the image forming stations Pa to Pd.

In each of the image forming stations Pa to Pd, a toner image of each color is formed, and is superposed on the supporting surface of the paper P which is electrostatically attracted by the transfer and transport belt 216 and is transported. When the transfer of the image by the fourth image forming station Pd is completed, the sheet P is sequentially peeled from the transfer conveying belt 216 from the leading end portion of the sheet by the discharging discharging device and guided to the fixing device 217. Finally, the paper P on which the toner image is fixed is a paper discharge port (not shown).
Is ejected onto the paper ejection tray 220.

In the above description, LSU 227a ...
Optical writing is performed on the photoconductor drums 222a to 222d by scanning and exposing a laser beam at 227d. However, a writing optical system (LED head) including a light emitting diode array and an imaging lens array may be used instead of the LSU. Compared to LSU, LED head
It is small in size and silent because there are no moving parts. Therefore, it can be preferably used in an image forming apparatus such as a tandem system (system in which a plurality of photosensitive drums are arranged in parallel) that requires a plurality of optical writing units, such as a digital color copying machine.

A sheet conveying device according to an embodiment of the present invention will be described with reference to registration rollers 212 with reference to FIGS.

As shown in FIG. 2, the registration rollers 212
Is the first registration roller 11 and the second registration roller 12
The rotation shaft 12a of the second registration roller 12 is rotatably supported by the frame 13 of the apparatus main body.
The first registration roller 11 is provided so that it can come into contact with and separate from the second registration roller 12.

Rotating shaft 11 of the first registration roller 11
A is inserted into the insertion hole of the registration roller support 14 and is rotatably supported. This registration roller support 1
4 has an engaging groove 14a that engages with the frame 13, and the direction in which the rotating shaft 11a of the first registration roller 11 and the rotating shaft 12a of the second registration roller 12 are connected (the direction of arrow A in FIG. 2). ) Is slidably engaged with.

Further, the rotation shaft 12a of the second registration roller 12 is rotatably inserted and supported by the registration roller support 14 and has a long hole 14b having a length larger than the sliding amount of the registration roller support 14. A manual knob 15 is provided, which is loosely inserted in the elongated hole 14b and is provided at one end of the rotary shaft 12a for manually rotating the second registration roller 12 when a jam occurs.

Then, one end of a spring 16 for pulling the first registration roller 11 and pressingly contacting the second registration roller 12 is locked to the lower end of the elongated hole 14b of the registration roller support 14, and the other end of this spring 16 is used as a device. It is locked to the body. The spring 16 and the registration roller support 14 constitute pressure contact means for the first registration roller 11 and the second registration roller 12, and the pressure contact means are provided at both ends of the rotary shaft 11a of the first registration roller 11. The first registration roller 11 is pulled toward the second registration roller 12 side by the urging force of the spring 16 and brought into pressure contact with the second registration roller 12.

Next, a method of separating the first registration roller 11 from the second registration roller 12 will be described with reference to FIGS.
The first registration roller 11 is moved to the upper side in the drawing against the attraction force to the second registration roller 12 side by the urging force of the first registration roller 11 to release the engagement between the engagement groove 14a and the frame 13.
And the second registration roller 12 are separated from each other.

At this time, the rotation shaft 12a of the second registration roller 12 is caused by the elongated hole 14b of the registration roller support 14.
Allows the registration roller support 14 to move upward without interfering with the movement of the registration roller support 14.

After the registration roller support 14 is moved upward, the first registration roller 11 is removed from the registration roller support 14 by removing the rotary shaft 11a of the first registration roller 11 from the registration roller support 14.
4, the first registration roller 11 is removed, and only the registration roller support body 14 from which the first registration roller 11 is removed is engaged with the frame 13.

As described above, the first registration roller 11 can be separated from and removed from the second registration roller 12 without removing the spring 16.
The spring 16 can be prevented from being lost or dropped into the main body of the apparatus, and the first registration roller 11 can be stably pressed against the second registration roller 12 with a predetermined pressing force.

Moreover, the registration roller support 14 has the rotation shaft 1 so that the rotation shaft 12a of the second registration roller 12 does not get in the way when the registration roller support 14 moves.
Since the elongated hole 14b for inserting the 2a is formed, it is possible to move the registration roller support 14 without lowering the strength of the registration roller support 14 against the urging force (pulling force) of the spring 16. There is.

Further, in the above embodiment, a length longer than the movement amount of the registration roller support 14 is set so that the rotation shaft 12a of the second registration roller 12 does not get in the way when the registration roller support 14 moves. A hole 14b is formed, and the rotary shaft 12a of the second registration roller 12 is inserted through the long hole 14b. The part for supporting the rotary shaft 11a of the first registration roller 11 and the part for mounting the spring 16 are first and second parts. The registration roller support 14 may be formed by connecting the rotation shaft 12a of the two registration rollers 12 with a curved arm that bypasses the rotation shaft 12a.

[0049]

According to the transporting apparatus of the present invention, the first rotating body is pulled from the position sandwiching the second rotating body by the pressure contact means and is brought into pressure contact with the second rotating body, which is stable. The pressure contact force of the first rotating body to the second rotating body can be obtained.

Therefore, since the first rotating body is slidably engaged with the apparatus frame in the direction of pressingly contacting the second rotating body, the first rotating body is detached, or
At the time of separation from the second rotating body, it suffices that the rotating body support is slid from the device frame and removed, and the first rotating body can be separated from the second rotating body without removing the biasing body. It is possible to reliably prevent the urging body from being lost or falling into the device.

Further, since the rotary body support is provided with the elongated hole having a length larger than the sliding amount of the rotary body support into which the rotary shaft of the second rotary body is loosely inserted, the rotary movement of the rotary body support is slid. At the same time, the rotation shaft of the second rotating body can be moved without obstruction, and further, the reduction of the strength against the biasing force of the biasing body can be prevented.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view of a digital color copying machine using a sheet conveying device of the present invention.

FIG. 2 is a perspective view showing an embodiment of a sheet conveying device of the invention.

FIG. 3 is a front view showing a pressure contact state of a first registration roller with a second registration roller in FIG.

FIG. 4 is a side sectional view showing a state where the first registration roller in FIG. 2 is pressed against the second registration roller.

5 is a front view showing a state where the first registration rollers in FIG. 2 are separated from the second registration rollers.

FIG. 6 is a side sectional view showing a state where the first registration roller in FIG. 2 is separated from the second registration roller.

[Explanation of symbols]

1 Copier body 11 First registration roller 11a rotating shaft 12 Second registration roller 12a rotating shaft 13 frames 14 Registration roller support 14b long hole 15 Manual knob 16 springs

─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Tetsutaka Okazaki 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Fumio Shimazu 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Sharp shares In-company (72) Inventor Kiyoshi Toizumi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka (56) References JP-A-4-292348 (JP, A) JP-A-63-18762 (JP, A) ) Japanese Patent Laid-Open No. 3-36133 (JP, A) Actual Development Sho 60-9847 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 5/06

Claims (3)

(57) [Claims] 1. A paper transporting apparatus for pressing a first rotating body and a second rotating body against each other to form a nip portion, and gripping and transporting a sheet in the nip portion, wherein the first rotating body is A pressure contacting means for pulling from a position sandwiched by the second rotating body to contact the second rotating body with pressure is provided, and the rotating shaft of the first rotating body is inserted into the pressure contacting means so that the rotating shaft is rotatable. The rotary body support has an insertion hole for supporting the shaft, and the biasing body has one end attached to the rotary body support and the other end attached to the apparatus main body side. A hole is provided which is slidably engaged with the device frame in a direction in which the first rotating body is pressed against the second rotating body, and in which a rotation shaft of the second rotating body is loosely inserted. A paper transport device characterized by. 2. The rotary body support has a hole in which the rotary shaft of the second rotary body is loosely inserted, and the hole is a long hole having a length larger than a sliding amount of the rotary body support to the apparatus frame. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. 3. A sheet conveying device for pressing a first rotating body and a second rotating body against each other to form a nip portion, and gripping and conveying a sheet in the nip portion. A pressure contacting means for pulling from a position sandwiched by the second rotating body to contact the second rotating body with pressure is provided, and the rotating shaft of the first rotating body is inserted into the pressure contacting means so that the rotating shaft is rotatable. The rotary body support has an insertion hole for supporting the shaft, and the biasing body has one end attached to the rotary body support and the other end attached to the apparatus main body side. A curved arm is formed that is slidably engaged with the device frame in a direction in which the first rotating body is pressed against the second rotating body and that bypasses the rotation axis of the second rotating body. Characteristic paper transport device.