JP3937768B2 - Paper reversing device, paper reversing method, post-processing device, and image forming apparatus - Google Patents

Description

【００５８】
表１に示した各部は下記のように図２〜４におけるＳ１〜Ｓ５の各段階を経て用紙を連続して反転搬送する。
【００５９】
１枚目の用紙Ｐ１の搬入段階において、駆動ローラ１２２と従動ローラ１２１とにより用紙Ｐ１を搬入し、用紙Ｐ１を停止部材１３１まで落下させる。図５は搬入段階が終了し、用紙Ｐ１が停止部材１３１により支持されている状態を示し、図２のＳ１に相当する。停止部材１３１は用紙Ｐ１の上端（搬入方向後端）Ｐ１Ｕが案内部材としての突起１２４Ａの下端Ｑ（案内端）よりも下になる第１位置Ｖ１に設定される。
【００６０】
段階Ｓ２において、停止部材１３１は用紙Ｐ１の上端Ｐ１Ｕを突起１２４Ａの下端Ｑよりも上まで上昇させるような第２位置Ｖ２に設定される。段階Ｓ２における停止部材１３１の第２位置Ｖ２への上昇により、用紙Ｐ１の上端Ｐ１Ｕは搬入路１２７から退避して搬出路１２８に臨む。図７は段階Ｓ２の状態を示す。
【００６１】
このような、用紙Ｐ１の上端Ｐ１Ｕの搬出路１２８への誘導は、前記した搬入路１２７、突起１２４Ａ及び搬出路１２８の形状により確実に行われる。また、突起１２４Ａの移動により、上端Ｐ１Ｕを搬出路１２８へ誘導することも可能である。
【００６２】
段階Ｓ３は、２枚目の用紙Ｐ２を搬入する段階である。２枚目の用紙Ｐ１の搬入は１枚目の用紙Ｐ１の上端（搬入方向後端）Ｐ１Ｕが搬入路１２７から退避した状態で実行され、Ｓ４の段階への移行、即ち、停止部材１３１の第１位置Ｖ１への降下は、段階Ｓ３で示すように、１枚目の用紙Ｐ１の上端部と２枚目の用紙Ｐ２の下端部とが重なった後に実行される。
【００６３】
次の段階Ｓ４において、２枚目の用紙Ｐ２が駆動ローラ１２２と従動ローラ１２１のニップから離れ落下して停止部材１３１上で停止する。次の段階Ｓ５において、停止部材１３１は第３位置Ｖ３に上昇して、１枚目の用紙Ｐ１の上端（搬出方向先端）Ｐ１Ｕ及び２枚目の用紙Ｐ２の上端（搬出方向先端）Ｐ２Ｕを駆動ローラ１２２と従動ローラ１２３とのニップに到達させる。図８は段階Ｓ５にある反転搬送部１３を示す。
【００６４】
段階Ｓ１〜Ｓ５を繰り返すことにより、２枚単位で反転搬送が行われる。
＜折り畳み処理＞
折り畳み処理を図９、１０を参照して説明する。図９は折り畳み部１４、１５の構成を、図１０は用紙Ｐの２カ所で折り畳む三つ折り処理（Ｚ折り処理）工程をそれぞれ示す。
【００６５】
図９（ａ）に示す折り畳み部１４は駆動ローラとしての折り畳みローラ１４１、１４２、これらの折り畳みローラにそれぞれ接触して従動回転する従動ローラ１４３、１４４及び案内部材１４５で構成される。折り畳みローラ１４１は後に説明するように変位可能である。
【００６６】
図９（ｂ）に示す折り畳み部１５は駆動ローラとしての折り畳みローラ１５１、１５２、これらの折り畳みローラにそれぞれ接触して従動回転する従動ローラ１５３、１５４及び案内部材１５５で構成される。折り畳みローラ１５１は後に説明するように変位可能である。
【００６７】
折り畳みモードにおいては、用紙Ｐに対して折り畳み部１４により、例えば、その先端から１／４の位置で第１の折り畳み処理が行われ、更に、折り畳まれた用紙Ｐの先端から１／４（用紙全長の１／４）の位置で折り畳み部１５により折り畳み処理が行われて、用紙Ｐは、例えば、Ｚ折り処理される。
【００６８】
図１０（ａ）において、折り畳みローラ１４１と折り畳みローラ１４２とが離間し、従動ローラ１４３、１４４がそれぞれ折り畳みローラ１４１、１４２に圧接した状態で用紙Ｐを搬送し折り畳み部１４に導入する。用紙Ｐが基準位置Ｒから所定距離Ｄ搬送された段階でセンサＳＳ２の用紙先端検知信号により、折り畳みローラ１４１、１４２の駆動を停止し、図１０（ｂ）の折り畳み工程に移行する。
【００６９】
図１０（ｂ）において、折り畳みローラ１４１及び従動ローラ１４３を変位させて折り畳みローラ１４１と折り畳みローラ１４２とを圧接させた後に、折り畳みローラ１４１を前記の導入時と同方向に回転駆動するとともに、折り畳みローラ１４２を前記導入時と反対方向に回転駆動して折り畳みを開始する。折り畳みローラ１４１と１４２の用紙Ｐに対する反対方向の搬送作用により用紙Ｐは屈曲し、折り畳みローラ１４１と折り畳みローラ１４２との間に折り目が進入する。なお、折り畳みローラ１４１、１４２側への用紙Ｐの屈曲を確実に行わせる突起１４５Ａを有する案内部材１４５が設けられる。更に図１０（ｃ）のように、折り畳みローラ１４１、１４２の回転を続行して折り畳みを行い、折り畳まれた用紙Ｐを搬送ローラ２１０で搬送して折り畳み部１５に導入する。
【００７０】
図１０（ｄ）に示すように折り畳み部１５の折り畳みローラ１５１と、１５２とが離間し、従動ローラ１５３、従動ローラ１５４がそれぞれ折り畳みローラ１５１、１５２に圧接した状態で用紙Ｐを導入し、折り畳まれた用紙Ｐの先端が基準位置Ｒから所定距離Ｄ搬送された段階でセンサＳＳ３の用紙先端検知信号に基づいて折り畳みローラ１５１を変位させて、折り畳みローラ１５２に圧接させる。圧接後、折り畳みローラ１５１を前記導入時と同一方向に回転駆動するとともに、折り畳みローラ１５２を前記導入時と反対方向に回転駆動する。折り畳みローラ１５１と１５２の用紙Ｐに対する反対方向の搬送作用により用紙Ｐは屈曲し、折り畳みローラ１５１と折り畳みローラ１５２との間にその折り目が進入する。なお、折り畳みローラ１５１、１５２側への用紙Ｐの屈曲を確実に行わせる突起１５５Ａを有する案内部材１５５が設けられる。図１０（ｅ）のように圧接後に折り畳みローラ１５２の回転方向を反転して用紙Ｐを折り畳む。図１０（ｆ）のように折り畳みローラ１５１、１５２の回転を続行して、用紙Ｐを折り畳みつつ、折り畳み部１５から用紙Ｐを排出し、搬送路１０へと搬送する。
【００７１】
図１０の例では用紙Ｐの先端から１／４の位置で折り畳みを行っている。センサＳＳ２、ＳＳ３はそれぞれ基準位置Ｒ、即ち、折り畳みローラ１４１と１４２の外周の接線及び折り畳みローラ１５１と１５２の外周の接線で示す位置からＤ＝１／４×ＬＴ（ＬＴは用紙Ｐの搬送方向の長さ）において用紙Ｐの先端を検知する。実際には、折り畳みローラ１４１、１４２、１５１、１５２の反転時間の遅れ等が考慮されて１／４×ＬＴより若干短く設定される。
【００７２】
センサＳＳ２、ＳＳ３は、用紙Ｐにおける折り畳みモードにより、或いは用紙サイズにより種々の位置に設定される。
【００７３】
図示のように、用紙Ｐの２カ所で折り畳み処理を行う工程において、用紙Ｐは折り畳み部１４に方向Ｚ１から導入され、折り畳み部１４から折り畳み部１５に方向Ｚ１にほぼ直角な方向Ｚ２に搬送されて送り込まれる。折り畳み部で折り畳み処理された用紙Ｐは方向Ｚ２にほぼ直角な方向Ｚ３に、即ち、方向Ｚ１とほぼ同一の方向Ｚ３に搬送される。
【００７４】
【発明の効果】
請求項１，２，７の何れかの発明により、停止部材を用いて反転搬送を行うので、反転搬送部への用紙の搬入と反転搬送部からの用紙の搬出とを同時に行い、反転搬送部内に複数の用紙が同時に走行することができるので、用紙間隔を短くすることが可能になり、反転搬送処理を高速で行うことが可能になる。また、所望の処理速度で反転搬送処理を行う場合には、用紙の搬送線速度を落とすことができるので、搬送が安定し、搬送故障の発生率を低くすることが可能になる。
【００７５】
しかも、反転搬送処理において、搬送用のモータが一方向に回転するだけであるので、モータへの負荷が軽減される。更に、複数枚単位で反転搬送するので、反転後の搬送線速を落とすことが可能になり、安定した搬送が可能になる。
【００７６】
請求項３の発明により、反転搬送処理における停止部材の制御が正確なタイミングで行われるので、反転搬送処理が安定して行われる。
【００７７】
請求項４の発明により、用紙反転装置が小型化される。
請求項５の発明により、高速で反転搬送処理を行うことが出来る後処理装置が実現される。
【００７８】
請求項６の発明により、高速で反転搬送処理を行うことが出来る画像形成装置が実現される。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る用紙反転装置の模式図である。
【図２】本発明の実施の形態に係る用紙反転方法を示す図である。
【図３】本発明の実施の形態に係る用紙反転方法を示す図である。
【図４】本発明の実施の形態に係る画像形成装置の一例を示す図である。
【図５】分岐部及び反転搬送部の断面図である。
【図６】反転搬送部の側面図である。
【図７】用紙反転装置の断面図である。
【図８】用紙反転装置の断面図である。
【図９】折り畳み部の構成を示す図である。
【図１０】三つ折り処理の工程を示す図である。
【符号の説明】
１０、２０、２１、２２、２３、２４ 搬送路
１２ 分岐部
１３ 反転搬送部
１４、１５ 折り畳み部
１６ 中間皿
１７ 綴じ部
１８ 固定排紙皿
１９ 昇降排紙皿
１２１、１２３、ＮＲ１、ＮＲ２ 従動ローラ
１２２、ＤＲ 駆動ローラ
１２４ 上側案内部材
１２５、１２６ 案内板
１２７、Ｒ１ 搬入路
１２８、Ｒ２ 搬出路
１２９ 通路
１３１、ＳＭ 停止部材
Ａ 画像形成装置本体
Ｂ 後処理装置
ＧＤ１、ＧＤ２ 案内部材
Ｍ１、Ｍ２ ステッピングモータ
Ｐ、Ｐ１、Ｐ２、Ｐ３ 用紙[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet reversing and conveying method for reversing and conveying sheets, a sheet reversing apparatus for sheets, a post-processing apparatus having a sheet reversing apparatus, and an image forming apparatus having a sheet reversing apparatus.
[0002]
[Prior art]
In many image forming apparatuses such as an electrophotographic apparatus, an image is formed on the upper surface of the conveyed paper. If the paper on which the image is formed is discharged as it is, the image is discharged in a state where the image is on the upper surface of the paper. . In general, in copying and printing, images are formed in ascending order from one page. Therefore, when a sheet is discharged with an image formed on the upper surface, the page order is reversed.
[0003]
In order to avoid such inconvenience, many image forming apparatuses have a reverse conveyance function, and in normal mode image formation, they are designed to discharge paper with the image surface facing down by reverse conveyance. ing.
[0004]
In the double-sided image forming apparatus, after forming an image on the front surface, the front and back are reversed and image formation is performed again to form an image on the back surface.
[0005]
Many image forming apparatuses are equipped with a paper reversing device for the reverse paper discharge and double-sided image formation.
[0006]
Many conventional paper reversing devices reverse the front and back by so-called switchback conveyance. In other words, the paper is carried into the reverse conveyance unit that performs the switchback conveyance, conveyed in one direction by the reverse roller in the reverse conveyance unit, and when the rear end of the paper conveyance direction reaches the position of the reverse roller, The direction of rotation is reversed and switchback conveyance is performed to reverse the front and back.
[0007]
[Problems to be solved by the invention]
In the conventional sheet reversing device described above, since the reversing conveyance is performed by the reversing roller provided in the reversing conveying unit, the succeeding sheet cannot be carried into the reversing conveying unit while the preceding sheet exists in the reversing conveying unit. . Accordingly, when the sheets are continuously reversed and conveyed, it is necessary to increase the interval between the sheets, and as a result, there is a problem that the processing speed of the reversed conveyance cannot be increased. Further, in order to increase the reverse conveyance processing speed using the conventional sheet reversing device, it is necessary to increase the sheet conveyance linear velocity, which causes a problem that the conveyance becomes unstable.
[0008]
An object of the present invention is to solve the above-described problems in a conventional sheet reversing apparatus.
[0009]
[Means for Solving the Problems]
The object of the present invention is achieved by the following invention.
[0010]
1. Reversing conveyance unit that reverses the front and back by switchback conveyance,
Carrying-in means for carrying the paper into the reversing conveyance unit;
Unloading means for unloading the sheet from the reverse conveying path;
Carry-in route,
Unloading route and
A sheet reversing device having a stop member that is disposed below the carry-in means and the carry-out means and reverses the conveyance direction of the paper carried by the carry-in means,
In continuous reverse conveyance of multiple sheets,
When the first sheet is carried into the reversing conveyance unit, the trailing direction of the sheet leaves the loading unit , and the loading direction of the sheet is greater than the end of the guide member that separates the loading path and the unloading path. The sheet is stopped by the stop member at the first position where the rear end is downward, and then the stop member is moved to the upper second position so that the rear end in the paper carry-in direction is moved from the end of the guide member. Is also retracted to the upper discharge path side ,
When the second sheet is carried into the reverse conveying section, the stop member is moved to the first sheet after the leading end of the second sheet reaches the position where the leading end of the first sheet overlaps the trailing end of the first sheet. Move to a position, stack a plurality of sheets on the stop member,
A sheet reversing apparatus, wherein a plurality of stacked sheets of paper are made to reach the unloading means with a rear end in the loading direction as a leading end in the unloading direction , and the stacked sheets of sheets are unloaded by the unloading means.
[0011]
2. The said carrying-in means consists of a driving roller and a first driven roller that contacts the driving roller , and the carrying-out means consists of the driving roller and a second driven roller that contacts the driving roller. Paper reversing device.
[0013]
3 . The sheet reversing according to 1 or 2 , further comprising a detecting unit that detects a leading edge of the sheet upstream of the carry-in unit, and controlling the movement of the stop member based on a detection signal of the detecting unit. apparatus.
[0014]
4 . Sheet reversing apparatus according to any one of the 1-3, wherein the reverse conveying path between the stop member and the carrying means and the unloading means is substantially vertical.
[0015]
5 . Post-processing apparatus characterized by having a sheet reversing device and a post portion disposed upstream or downstream of the paper reversing apparatus according to any one of claims 1-4.
[0016]
6 . An image forming apparatus, comprising a sheet reversing device according images to any one of claim 1 to 4 for the reversal conveyance processing to the sheet on which the image forming unit and an image is formed is formed into a sheet .
[0017]
7). The first sheet is loaded into a reversing conveyance unit that reverses the front and back sides by switchback conveyance, the rear end in the sheet loading direction is separated from the loading means, and the rear end in the sheet loading direction separates the loading path and the unloading path. The sheet is stopped in the reversing conveyance unit by a stop member at a first position that is below the end of the guide member ,
Next, the stop member is moved to the second upper position, and the rear end of the paper in the carry-in direction is retracted to the carry-out path side above the end of the guide member,
Subsequently, when the second sheet of paper is carried into the reversing conveyance unit, after the leading edge of the second paper in the carrying direction reaches the position where it overlaps the trailing edge of the first paper in the carrying direction, the stop member is Move to the first position and stack a plurality of sheets on the stop member;
With the rear end in the carry-in direction of the plurality of stacked sheets being made the leading end in the carry-out direction, the unloading means is reached,
A sheet reversing method for a sheet, wherein the plurality of sheets are unloaded from the reversing conveyance unit by the unloading means.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
<Reverse conveying method>
First, a paper reversing apparatus and a paper reversing method according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of a sheet reversing apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are diagrams illustrating a sheet reversing method according to an embodiment of the present invention.
[0019]
The sheet reversing device according to the present embodiment includes a driving roller DR, driven rollers NR1 and NR2, two parallel guide plates WL1 and WL2, guide members GD1 and GD2, and a stop member SM. The guide plates WL1 and WL2 and the stop member SM constitute a reverse conveying unit that switches back and conveys the paper, and the driving roller DR as the first driving roller and the driven roller NR1 as the first driven roller are fed to the reverse conveying unit. The drive roller DR as the second drive roller and the driven roller NR2 as the second driven roller constitute a carry-out means for carrying out the paper from the reverse conveying unit.
[0020]
The driving roller DR is driven to rotate in the clockwise direction in the drawing as indicated by an arrow, and carries the paper into the reverse conveying unit and carries the paper P out of the reverse conveying unit.
[0021]
The guide plates WL1 and WL2 store the loaded paper, the guide member DG1 guides the paper when the paper is carried in and out, and the guide member GD2 separates the carry-in path R1 and the carry-out path R2, and Guidance is made so that the following paper does not collide.
[0022]
In the present embodiment, the sheet is loaded between the guide plates WL1 and WL2 and then switched back and conveyed, so that the front and back of the sheet are reversed.
[0023]
S1 to S5 in FIGS. 2 and 3 show stages in the process of reversing and conveying a plurality of sheets.
[0024]
In the loading stage S1 of the first sheet P1, the sheet P1 is loaded by the driving roller DR and the driven roller NR1, and the sheet P1 is dropped to the stop member SM. The stop member SM is set to a first position V1 where the upper end (rear end in the carry-in direction) P1U of the paper P1 is lower than the lower end (guide end) of the guide member GD2.
[0025]
In step S2, the stop member SM is set to the second position V2 that raises the upper end P1U of the paper P1 to a position higher than the lower end (guide end) of the guide member GD2. The upper end P1U of the sheet P1 is retracted from the carry-in path R1 to the carry-out path R2 by the raising of the stop member SM to the second position V2 in step S2.
[0026]
Such guidance of the upper end P1U of the paper P1 to the carry-out path R2 is realized by the shapes of the carry-in path R1, the guide member GD2, and the carry-out path R2, as will be described later. It is also possible to guide the upper end P1U to the carry-out path R2 by movement such as rotation of the guide member GD2.
[0027]
In step S3, the second sheet P is carried in. The second sheet P2 is carried in with the upper end (rear end in the carry-in direction) P1U of the first sheet P1 retracted from the carry-in path R1. Thereby, the collision and interference of the two sheets P1 and P2 are prevented, and smooth conveyance is performed. The transition to the stage of S4, that is, the lowering of the stop member SM to the first position V1, causes the upper end part of the first sheet P1 and the lower end part of the second sheet P2 to move as shown in stage S3. It is executed after overlapping.
[0028]
In the next step S4, the stop member SM is lowered to the first position V1. Accordingly, the second sheet P2 falls off the nip between the driving roller DR and the driven roller NR1, and stops on the stop member SM. In this way, the two sheets P1, P2 are stacked on the stop member SM.
[0029]
In the next step S5, the stop member SM is moved up to the third position V3 to drive the upper end (leading end in the unloading direction) P1U of the first sheet P1 and the upper end (leading end in the unloading direction) P2U of the second sheet P2. It reaches the nip between the roller DR and the driven roller NR2.
[0030]
By repeating steps S1 to S5, two sheets of paper are carried out of the paper reversing device.
[0031]
In the reverse conveyance process described above, the driving roller DR is continuously driven by the stepping motor M1 and continuously rotates clockwise. The stop member SM is driven by the stepping motor M2 and is displaced to the first to third positions V1 to V3. The displacement of the stop member SM is controlled by the control means CR based on a paper leading edge detection signal from the detection means SS1 discharged upstream of the carry-in means composed of the driving roller DR and the driven roller NR1, and preferably upstream in the vicinity. The stop member SM is displaced to the first to third positions V1 to V3 as described above in a preset time from the detection of the tip by the detection means.
[0032]
It is also possible to carry out the reverse conveyance in units of three or more sheets.
<Image forming apparatus>
Next, an image forming apparatus equipped with the paper reversing device will be described. In the image forming apparatus shown in FIG. 4, a post-reversing device B is provided with a paper reversing device. The sheet reversing device can be provided in the paper discharge unit or re-conveying unit 8 of the image forming apparatus main body A.
[0033]
FIG. 4 shows an image forming apparatus according to an embodiment of the present invention. The image forming apparatus includes an image forming apparatus main body A, an automatic document feeder ADF, and a post-processing apparatus B.
[0034]
The image forming apparatus main body A shown in the figure includes an image reading unit 1, an image processing unit 2, an image writing unit 3, an image forming unit 4, a paper feeding unit 5, a conveying unit 6, a fixing unit 7, a re-conveying unit (automatic double-sided copy conveying). Unit ADU) 8, control means 9 and the like.
[0035]
The sheet feeding means 5 includes a cassette sheet feeding unit 5A, a large capacity sheet feeding unit (LCT) 5B, a manual sheet feeding unit 5C, an intermediate sheet feeding roller 5D, and a registration roller 5E.
[0036]
The transport unit 6 includes a transport belt 6A, a transport path switching plate 6B, a paper discharge roller 6C, and the like.
[0037]
An automatic document feeder ADF is mounted on the upper part of the image forming apparatus main body A. A post-processing device B is connected to the left side of the image forming apparatus main body A shown in the drawing on the paper discharge roller 6C side.
[0038]
The document d placed on the document table of the automatic document feeder ADF is conveyed in the direction of the arrow, the image on one or both sides of the document is read by the optical system of the image reading means 1, and is read by the CCD image sensor 1A.
[0039]
The analog signal photoelectrically converted by the CCD image sensor 1A is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing means 2, and then sent to the image writing means 3.
[0040]
In the image writing means 3, the output light from the semiconductor laser is irradiated onto the photosensitive drum of the image forming means 4 to form a latent image. In the image forming unit 4, processes such as charging, exposure, development, transfer, separation, and cleaning are performed. On the paper P sent out from the paper supply means 5, the image is transferred at the transfer portion.
[0041]
The paper P carrying the image is transported by the transport belt 6A, fixed by the fixing unit 7, and sent from the paper discharge roller 6C to the paper introduction unit 10A of the post-processing apparatus B. Alternatively, the single-sided image processed paper P sent to the re-transport unit 8 by the transport path switching plate 6B is again discharged from the paper discharge roller 6C after the double-sided image processing in the image forming unit 4. The paper P discharged from the paper discharge roller 6C is sent to the post-processing apparatus B.
[0042]
The post-processing device B finishes image recording and receives a paper P, a paper introduction unit 10A, a paper feeding device 11 that feeds additional paper F, a reverse conveyance unit 13, folding units 14 and 15, an intermediate plate 16, and a binding unit. 17, a folding unit 25, a fixed discharge tray 18, a vertically movable lift tray 19 and a fixed discharge portion 27, which are connected by transport paths 10, 20, 21, 22, 23, 24, etc. Yes. One of the features of the post-processing apparatus B according to the embodiment of the present invention is that the reverse conveyance unit 13 is arranged after the paper introduction unit 10A, and the folding units 14 and 15, the binding unit 17 are arranged downstream of the reverse conveyance unit 13. The post-processing unit such as the middle folding unit 25 is disposed.
[0043]
The paper reversing device shown in FIG. 1 is provided in the post-processing device B of the image forming apparatus shown in FIG. Further, in an image forming apparatus that does not include the post-processing apparatus B and discharges paper to a paper discharge tray, the paper reversing device shown in FIG.
[0044]
The post-processing apparatus B performs post-processing in the following processing mode.
(1) Simple paper discharge mode The paper P introduced from the paper introduction unit 10A is simply discharged in the order of introduction. In this mode, the paper P is discharged to the fixed paper discharge tray 18 through the transport paths 10 and 20.
(2) Folding mode The paper P is folded in one or two places, and is subjected to two-fold processing or three-fold processing and discharged.
[0045]
The paper P introduced from the paper introduction unit 10A is conveyed to the folding units 14 and 15 and is folded by the folding units 14 and 15, and then discharged to the elevating paper discharge tray 19 through the conveyance path 10 and the conveyance path 22. Paper. There are cases where the folding parts 14 and 15 are used to perform a tri-folding process, and cases where only the folding part 14 is used to perform a half-folding process.
(3) Binding mode A binding process is performed for each of a plurality of sheets P and the sheets are discharged.
[0046]
A set number of sheets of paper P conveyed from the conveyance path 10 to the conveyance path 23 are stacked on the intermediate tray 16, and then bound by the binding unit 17. After the binding process, the sheets P are discharged to the lift sheet discharge tray 19.
(4) Mode in which (2) Folding mode and (3) Binding mode are combined and processed (5) Center folding mode The central portion of the paper P is bound by the binding portion 17 and a knife-like protruding member 251 is used. A middle folding process is performed, and the paper is discharged to the fixed paper discharge unit 27 via the paper discharge path 26.
[0047]
In each mode, by feeding the additional paper F from the paper tray 11 and adding it to the paper P supplied from the image forming apparatus main body A, the front cover, back cover, partition, etc. for each bundle of paper P Can be added.
[0048]
Next, FIG. 5 which is a cross-sectional view of the branching unit 12 and the reverse transporting unit 13 constituting the paper reversing device of FIG. 1 and the structure of the branching unit 12 and the reverse transporting unit 13 according to FIG. Will be explained.
[0049]
The branching unit 12 carries the paper P <b> 1 into the reverse conveyance unit 13 from the conveyance path 10 as the main conveyance path and carries it out from the reverse conveyance unit 13 to the conveyance path 10.
[0050]
The branching unit 12 carries the paper P <b> 1 into the reverse conveyance unit 13 from the conveyance path 10 as the main conveyance path and carries it out from the reverse conveyance unit 13 to the conveyance path 10. The branch portion 12 includes an upper guide member 124, lower guide members 125B and 126B, and a driving roller 122 and driven rollers 121 and 123 that are rotationally driven by a stepping motor M1, and the branch portion 12 includes an upper guide member 124 and a lower side. It has a carry-in path 127 formed by the guide member 125B and a carry-out path 128 formed by the upper guide member 124 and the lower guide member 126B.
[0051]
The driving roller 122 as the first driving roller and the driven roller 121 as the first driven roller constitute a carrying-in means, and the driving roller 122 as the second driving roller and the driven roller 123 as the second driven roller constitute a carrying-out means. To do. The protrusion 124A of the upper guide member 124 separates the carry-in path 127 and the carry-out path 128.
[0052]
The vertical portions of the guide plates 125 and 126 facing each other in parallel constitute a sheet storage portion having a passage 129, and the upper portions opened above the guide plates 125 and 126 constitute lower guide members 125B and 126B. As described above, the carry-in path 127 and the carry-out path 128 for the paper P1 are formed.
[0053]
The upper guide member 124 has a projection 124A as a guide member at its lower end. The tip Q of the protrusion 124A is set to occupy a position closer to the carry-in path 127 than the vertical parallel portion (paper storage portion) of the guide plate 125, as indicated by the vertical line L drawn on the tip Q. Due to such a shape of the protrusion 124A, the sheet P1 carried in from the carry-in path 127 is reliably removed when the upper end of the sheet P1 falls off the nip between the driving roller 122 and the driven roller 121 and is supported by the stop member 131. It is moved from the carry-in route to the carry-out route 128.
[0054]
As shown in FIG. 6, the guide plates 125 and 126 have notches 125 </ b> A and 126 </ b> A at the center in the conveyance path width direction. As shown in FIG. 5, a stop member 131 having an introduction portion opened upward is provided at the notches 125A and 126A. The stop member 131 is coupled to the toothed belt 135 by the coupling member 130, and is moved up and down by being driven by the stepping motor M2. As will be described later, the stop member 131 takes first to third positions V1 to V3, and the first to third positions V1 to V3 are changed according to the sheet size.
[0055]
On both sides of the guide plates 125 and 126 in the conveyance path width direction, regulating members 13A and 13B as side end regulating members are provided.
<Reverse conveyance processing>
The reverse conveyance process will be described with reference to FIGS. The reverse conveyance process is performed in the steps already described with reference to FIGS.
[0056]
Each component in FIG. 5 corresponds to the component in FIG. 1 as shown in Table 1.
[0057]
[Table 1]

[0058]
Each section shown in Table 1 continuously reverses and conveys the paper through the steps S1 to S5 in FIGS.
[0059]
At the stage of loading the first sheet P1, the sheet P1 is loaded by the driving roller 122 and the driven roller 121, and the sheet P1 is dropped to the stop member 131. FIG. 5 shows a state where the carry-in stage is completed and the paper P1 is supported by the stop member 131, which corresponds to S1 in FIG. The stop member 131 is set to a first position V1 where the upper end (rear end in the carry-in direction) P1U of the paper P1 is below the lower end Q (guide end) of the protrusion 124A as a guide member.
[0060]
In step S2, the stop member 131 is set to the second position V2 that raises the upper end P1U of the paper P1 to above the lower end Q of the protrusion 124A. As the stop member 131 rises to the second position V2 in step S2, the upper end P1U of the sheet P1 is retracted from the carry-in path 127 and faces the carry-out path 128. FIG. 7 shows the state of step S2.
[0061]
Such guidance of the upper end P1U of the paper P1 to the carry-out path 128 is reliably performed by the shapes of the carry-in path 127, the protrusion 124A, and the carry-out path 128 described above. Further, the upper end P1U can be guided to the carry-out path 128 by the movement of the protrusion 124A.
[0062]
Step S3 is a step of carrying in the second sheet P2. The second sheet P1 is carried in with the upper end (rear end in the carry-in direction) P1U of the first sheet P1 retracted from the carry-in path 127, and the process proceeds to the step S4, that is, the stop member 131 is moved to the first position. The lowering to the first position V1 is executed after the upper end of the first sheet P1 and the lower end of the second sheet P2 overlap as shown in step S3.
[0063]
In the next step S 4, the second sheet P 2 falls off the nip between the driving roller 122 and the driven roller 121 and stops on the stop member 131. In the next step S5, the stop member 131 is moved up to the third position V3 to drive the upper end (leading end in the unloading direction) P1U of the first sheet P1 and the upper end (leading end in the unloading direction) P2U of the second sheet P2. The nip between the roller 122 and the driven roller 123 is reached. FIG. 8 shows the reverse conveying unit 13 in step S5.
[0064]
By repeating steps S1 to S5, reverse conveyance is performed in units of two sheets.
<Folding process>
The folding process will be described with reference to FIGS. FIG. 9 shows the configuration of the folding sections 14 and 15, and FIG. 10 shows a three-fold process (Z-fold process) for folding the paper P at two locations.
[0065]
9A includes folding rollers 141 and 142 as driving rollers, driven rollers 143 and 144 that rotate in contact with the folding rollers, and a guide member 145, respectively. The folding roller 141 can be displaced as will be described later.
[0066]
9B includes folding rollers 151 and 152 as driving rollers, driven rollers 153 and 154 that rotate in contact with the folding rollers, respectively, and a guide member 155. The folding roller 151 can be displaced as will be described later.
[0067]
In the folding mode, the folding unit 14 performs, for example, a first folding process on the paper P at a position ¼ from the leading edge thereof, and further ¼ (paper from the leading edge of the folded paper P). The folding process is performed by the folding unit 15 at a position of 1/4) of the total length, and the paper P is subjected to, for example, a Z-folding process.
[0068]
In FIG. 10A, the folding roller 141 and the folding roller 142 are separated from each other, and the paper P is conveyed and introduced into the folding unit 14 with the driven rollers 143 and 144 being in pressure contact with the folding rollers 141 and 142, respectively. When the paper P is conveyed by a predetermined distance D from the reference position R, the driving of the folding rollers 141 and 142 is stopped by the paper leading edge detection signal of the sensor SS2, and the process proceeds to the folding process of FIG.
[0069]
In FIG. 10B, after the folding roller 141 and the driven roller 143 are displaced and the folding roller 141 and the folding roller 142 are pressed against each other, the folding roller 141 is rotationally driven in the same direction as that at the time of introduction, and the folding roller 141 is folded. Folding is started by rotating the roller 142 in the direction opposite to that at the time of introduction. The sheet P is bent by the conveying action of the folding rollers 141 and 142 in the opposite direction to the sheet P, and a crease enters between the folding roller 141 and the folding roller 142. Note that a guide member 145 having a protrusion 145A for reliably bending the paper P toward the folding rollers 141 and 142 is provided. Further, as shown in FIG. 10C, the folding rollers 141 and 142 are continuously rotated to be folded, and the folded paper P is conveyed by the conveying roller 210 and introduced into the folding unit 15.
[0070]
As shown in FIG. 10D, the folding rollers 151 and 152 of the folding unit 15 are separated from each other, and the paper P is introduced and folded while the driven rollers 153 and 154 are in pressure contact with the folding rollers 151 and 152, respectively. When the leading edge of the sheet P is conveyed by a predetermined distance D from the reference position R, the folding roller 151 is displaced based on the sheet leading edge detection signal from the sensor SS3 and is brought into pressure contact with the folding roller 152. After the press contact, the folding roller 151 is rotationally driven in the same direction as that during the introduction, and the folding roller 152 is rotationally driven in the direction opposite to that during the introduction. The sheet P is bent by the conveying action of the folding rollers 151 and 152 in the opposite direction to the sheet P, and the fold enters between the folding roller 151 and the folding roller 152. Note that a guide member 155 having a protrusion 155A for reliably bending the paper P toward the folding rollers 151 and 152 is provided. As shown in FIG. 10E, the sheet P is folded by reversing the rotation direction of the folding roller 152 after the press contact. As illustrated in FIG. 10F, the folding rollers 151 and 152 continue to rotate, and the sheet P is discharged from the folding unit 15 and conveyed to the conveyance path 10 while folding the sheet P.
[0071]
In the example of FIG. 10, folding is performed at a position ¼ from the leading edge of the paper P. Each of the sensors SS2 and SS3 has a reference position R, that is, D = 1/4 × LT (LT is the conveyance direction of the paper P) from the positions indicated by the outer tangent of the folding rollers 141 and 142 and the outer tangent of the folding rollers 151 and 152. The leading edge of the paper P is detected. Actually, it is set to be slightly shorter than ¼ × LT in consideration of a delay in the reversal time of the folding rollers 141, 142, 151, and 152.
[0072]
The sensors SS2 and SS3 are set at various positions according to the folding mode of the paper P or according to the paper size.
[0073]
As shown in the figure, in the process of performing folding processing at two locations on the paper P, the paper P is introduced into the folding portion 14 from the direction Z1, and is conveyed from the folding portion 14 to the folding portion 15 in a direction Z2 substantially perpendicular to the direction Z1. Sent in. The paper P folded by the folding unit is conveyed in a direction Z3 substantially perpendicular to the direction Z2, that is, in a direction Z3 substantially the same as the direction Z1.
[0074]
【The invention's effect】
According to the invention of any one of claims 1 , 2, and 7, the reversal conveyance is performed using the stop member, so that the paper is carried into the reversal conveyance unit and the paper is unloaded from the reversal conveyance unit at the same time, In addition, since a plurality of sheets can run simultaneously, the sheet interval can be shortened, and the reverse conveyance process can be performed at a high speed. In addition, when reverse conveyance processing is performed at a desired processing speed, the conveyance linear velocity of the paper can be reduced, so that conveyance is stabilized and the occurrence rate of conveyance failure can be reduced.
[0075]
Moreover, in the reverse conveyance process, since the conveyance motor only rotates in one direction, the load on the motor is reduced. Furthermore, since reverse conveyance is performed in units of a plurality of sheets, it is possible to reduce the conveyance linear velocity after reversal, and stable conveyance becomes possible.
[0076]
According to the third aspect of the present invention, the control of the stop member in the reverse conveyance process is performed at an accurate timing, so that the reverse conveyance process is stably performed.
[0077]
According to the invention of claim 4 , the sheet reversing device is miniaturized.
According to the invention of claim 5, a post-processing apparatus capable of performing the reverse conveying process at high speed is realized.
[0078]
According to the sixth aspect of the present invention, an image forming apparatus capable of performing reverse conveyance processing at high speed is realized.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a sheet reversing device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a sheet reversing method according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a sheet reversing method according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.
FIG. 5 is a cross-sectional view of a branching unit and a reverse conveying unit.
FIG. 6 is a side view of the reversing conveyance unit.
FIG. 7 is a cross-sectional view of the paper reversing device.
FIG. 8 is a cross-sectional view of the sheet reversing device.
FIG. 9 is a diagram illustrating a configuration of a folding unit.
FIG. 10 is a diagram illustrating a process of tri-fold processing.
[Explanation of symbols]
10, 20, 21, 22, 23, 24 Transport path 12 Branching section 13 Reverse transport section 14, 15 Folding section 16 Intermediate tray 17 Binding section 18 Fixed discharge tray 19 Lifting discharge tray 121, 123, NR1, NR2 Driven roller 122, DR drive roller 124 upper guide member 125, 126 guide plate 127, R1 carry-in path 128, R2 carry-out path 129 passage 131, SM stop member A image forming apparatus main body B post-processing apparatus GD1, GD2 guide member M1, M2 stepping motor P, P1, P2, P3 paper

Claims (7)

Reversing conveyance unit that reverses the front and back by switchback conveyance,
Carrying-in means for carrying the paper into the reversing conveyance unit;
Unloading means for unloading the sheet from the reverse conveying path;
Carry-in route,
Unloading route and
A sheet reversing device having a stop member that is disposed below the carry-in means and the carry-out means and reverses the conveyance direction of the paper carried by the carry-in means,
In continuous reverse conveyance of multiple sheets,
When the first sheet is carried into the reversing conveyance unit, the trailing direction of the sheet leaves the loading unit , and the loading direction of the sheet is greater than the end of the guide member that separates the loading path and the unloading path. The sheet is stopped by the stop member at the first position where the rear end is downward, and then the stop member is moved to the upper second position so that the rear end in the paper carry-in direction is moved from the end of the guide member. Is also retracted to the upper discharge path side ,
When the second sheet is carried into the reverse conveying section, the stop member is moved to the first sheet after the leading end of the second sheet reaches the position where the leading end of the first sheet overlaps the trailing end of the first sheet. Move to a position, stack a plurality of sheets on the stop member,
A sheet reversing apparatus, wherein a plurality of stacked sheets of paper are made to reach the unloading means with a rear end in the loading direction as a leading end in the unloading direction , and the stacked sheets of sheets are unloaded by the unloading means.   2. The carrying-in means comprises a driving roller and a first driven roller in contact with the driving roller, and the carrying-out means comprises the driving roller and a second driven roller in contact with the driving roller. The paper reversing device described.   3. The paper according to claim 1, further comprising a detection unit configured to detect a leading edge of the paper upstream of the carry-in unit, and controlling movement of the stop member based on a detection signal of the detection unit. Inversion device.   The sheet reversing device according to any one of claims 1 to 3, wherein a reversing conveyance path between the carrying-in means and the carrying-out means and the stop member is substantially vertical.   5. A post-processing device comprising: the paper reversing device according to claim 1, and a post-processing unit disposed upstream or downstream of the paper reversing device.   5. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; and a sheet reversing device according to claim 1 that performs a reversing conveyance process on the sheet on which the image is formed. . The first sheet is loaded into a reversing conveyance unit that reverses the front and back sides by switchback conveyance, the rear end in the sheet loading direction is separated from the loading means, and the rear end in the sheet loading direction separates the loading path and the unloading path. The sheet is stopped in the reversing conveyance unit by a stop member at a first position that is below the end of the guide member ,
Next, the stop member is moved to the second upper position, and the rear end of the paper in the carry-in direction is retracted to the carry-out path side above the end of the guide member,
Subsequently, when the second sheet of paper is carried into the reversing conveyance unit, after the leading edge of the second paper in the carrying direction reaches the position where it overlaps the trailing edge of the first paper in the carrying direction, the stop member is Move to the first position and stack a plurality of sheets on the stop member;
With the rear end in the carry-in direction of the plurality of stacked sheets being made the leading end in the carry-out direction, the unloading means is reached,
A sheet reversing method for a sheet, wherein the plurality of sheets are unloaded from the reversing conveyance unit by the unloading means.

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