JP3918459B2 - Paper post-processing method, paper post-processing apparatus, and image forming apparatus - Google Patents

Description

【０１３０】
表１は、中折り処理された用紙Ｓの折り高さＨを実測した結果を示す。
中折りローラ対６７１の挟持位置Ｘにおける折り圧は、何れも３０ｋｇである。用紙Ｓは、何れもＡ３判サイズ、斤量６４ｇ／ｍ²を用いた。用紙Ｓの枚数は２枚、５枚、１０枚、１６枚である。用紙Ｓの折り高さＨは、複数回の実測値の平均値である。
【０１３１】
図１８（ｂ）は中折り処理された用紙Ｓの折り高さＨの特性図である。図中、実線は本発明による実施例、破線は従来技術の比較例をそれぞれ示す。
【０１３２】
用紙Ｓの折り高さＨの平均値は、本発明による実施例によれば、中折り処理可能な最大用紙枚数１６枚の場合で３５ｍｍであり、従来技術の比較例の折り高さ４１ｍｍに比して少なく、良好な結果が得られた。用紙Ｓの枚数が２枚、５枚、１０枚の場合でも、本発明による実施例の用紙Ｓの折り高さＨが、従来の技術の比較例に比して少なく、良好な結果が得られた。
【０１３３】
［用紙の中折り制御の第２の実施の形態］
図１９は、用紙Ｓの中折り処理工程を説明する図である。図２０は用紙Ｓを中折り処理する工程のタイミングチャートである。以下、制御手段９０による用紙Ｓを中折り処理する工程の制御を説明する。なお、前記の第１の実施の形態と異なる点を説明する。
【０１３４】
中折りナイフ６６１の初期位置ＨＰ通過が、ＨＰセンサにより検知されてから所定時間ｔ１経過後、中折りナイフ６６１が後退する。更に所定時間ｔ２経過後、即ち、中折りナイフ６６１の初期位置ＨＰ通過検知後、所定時間ｔ６経過後にモータＭ２の駆動を開始させる。この駆動開始により、中折りローラ対６７１と加圧ローラ対６８１の正回転が開始される。
【０１３５】
中折りナイフ６６１と従動回転される中折りローラ対６７１により中折り処理された用紙Ｓは、駆動回転を開始した中折りローラ対６７１に挟持されて搬送され、用紙Ｓの中折り部の先端部は、駆動回転する加圧ローラ対６８１に挟持されて搬送される。
【０１３６】
用紙Ｓの先端部が加圧ローラ対６８１の挟持位置を越えた一時停止位置Ｚに到達したことを、排紙部センサＰＳ３により検知されると、制御手段９０はモータＭ２の駆動回転を停止させる。６９は排紙部センサＰＳ３の検出光路をオン、オフさせるアクチュエータである。
【０１３７】
加圧ローラ対６８１は、モータＭ２の駆動停止時点からタイマによる所定時間ｔ７を経過するまで停止状態を保持し、用紙Ｓの中折り部を強く圧接する。加圧ローラ対６８１の駆動回転が停止され、駆動回転が開始されるまでの所定時間ｔ７は、１〜１０秒の範囲内に設定される。加圧ローラ対６８１の正回転駆動及び停止時の押圧により、用紙Ｓの折り目が更に強く押圧される（図１３参照）。
【０１３８】
所定時間ｔ７の計時終了後、モータＭ２を再駆動して、中折りローラ対６７１と加圧ローラ対６８１の正回転駆動を開始する。タイマによる所定時間ｔ８経過後、モータＭ２の駆動回転を停止させる。この所定時間ｔ８経過中に、用紙Ｓは中折りローラ対６７１と加圧ローラ対６８１の正回転駆動により、機外に排出される（図１４参照）。
【０１３９】
なお、本発明の実施の形態では、複写機に接続した用紙後処理装置を示したが、プリンタ、ファクシミリ等の画像形成装置や軽印刷機等と接続して使用する用紙後処理装置にも適用可能である。
【０１４０】
【発明の効果】
以上説明したように、本発明の用紙後処理方法及び用紙後処理装置により、以下の優れた効果が得られる。
【０１４１】
用紙束の搬送方向中央部を、用紙突き出し手段の中折りナイフにより押圧しつつ中折りローラ対及び加圧ローラ対の挟持位置に押し込み、用紙束を中折り処理する用紙後処理装置において、用紙束の中折り部の先端部を加圧ローラ対の挟持位置近傍の所定位置で一定時間保持する事により、用紙束の折り目部の残留応力が消滅して、中折りされた用紙束の膨らみが少なくなる。特に、用紙枚数の多い用紙束における用紙束の膨らみが減少し、用紙束の仕上がり外観品質が向上する。
【０１４２】
また、複写機、プリンタ、ファクシミリ、これらの複合機等の画像形成装置により所望の高速画像形成処理が行われて排出された用紙は、用紙後処理装置において、中折り処理が用紙枚数に対応して正確な動作で行なわれ、用紙の折り目部の膨らみのない冊子が、画像形成装置の生産性を損なうことなく、迅速に作製される。
【図面の簡単な説明】
【図１】画像形成装置本体、画像読み取り装置、用紙後処理装置から成る画像形成システムの全体構成図。
【図２】後処理装置の用紙搬送経路を示す模式図。
【図３】後処理装置の上部機構を示す断面図。
【図４】後処理装置のステイプル処理部及び中折り処理部を示す断面図。
【図５】表紙と用紙の搬送経路と、用紙束の中綴じと中折り処理過程を示す模式図。
【図６】中綴じ処理された用紙の平面図、中綴じと中折りの後処理を施した用紙束の斜視図、及び後処理済みの用紙束を見開き状態にした斜視図。
【図７】中折り処理部の断面図。
【図８】中折り処理部の斜視図。
【図９】中折りローラ駆動手段の構成図。
【図１０】中折りナイフ駆動手段（第１駆動手段）の平面図。
【図１１】中折りナイフ駆動手段（第１駆動手段）の断面図。
【図１２】用紙の先端部が中折り形成部を通過する状態を示す断面図。
【図１３】中折り処理された用紙が加圧部を通過する状態を示す断面図。
【図１４】中折り及び加圧処理済みの用紙を排出する状態を示す断面図。
【図１５】用紙の中折り処理工程を説明する図。
【図１６】用紙を中折り処理する工程のタイミングチャート。
【図１７】後処理装置の制御を示すブロック図。
【図１８】中折り処理された用紙の膨らみを測定する装置の模式図、及び中折り処理された用紙の折り高さの特性図。
【図１９】用紙の中折り処理工程を説明する図。
【図２０】用紙を中折り処理する工程のタイミングチャート。
【符号の説明】
３０ 綴じ処理部
４０ ステイプル手段（綴じ手段）
６０ 中折り処理部
６４ 第２用紙積載部（スタック台）
６５ 折り部可動突き当て手段
６６ 用紙突き出し手段
６６０ 中折りナイフ駆動手段（第１駆動手段）
６６１ 中折り板部材（中折りナイフ）
６７ 中折り形成部
６７０ 中折りローラ駆動手段（第２駆動手段）
６７１ 中折りローラ対（第１の折りローラ対）
６７１Ａ，６７１Ｂ 中折りローラ
６８ 加圧部
６８１ 加圧ローラ対（第２の折りローラ対）
６８１Ａ，６８１Ｂ 加圧ローラ
９０ 制御手段
Ａ 画像形成装置本体
Ｃ 用紙後処理装置（後処理装置）
Ｈ 最大膨らみ高さ（折り高さ）
Ｓ 用紙
Ｘ 挟持位置
Ｙ 最大押し込み位置
Ｚ 一時停止位置
ａ 折り目部[0001]
BACKGROUND OF THE INVENTION
The present invention sequentially takes sheets discharged after image formation from an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile machine, and a multifunction machine having these functions into a sheet post-processing apparatus, and performs binding processing on the sheets. The present invention relates to a paper post-processing device having a function of performing post-processing such as folding processing and discharging to a paper discharge unit, a paper post-processing method, and an image forming apparatus including the paper post-processing device.
[0002]
[Prior art]
A sheet post-processing apparatus called a finisher is used as an apparatus that collates a plurality of sheets of image-recorded sheets discharged from the image forming apparatus for each number of copies and binds them by a stapling unit.
[0003]
The sheet post-processing apparatus is connected to a function of an image forming apparatus main body such as a copying machine or a printer, and is driven in response to a sequence operation of a copy or print process.
[0004]
Therefore, for an image forming apparatus capable of processing an image forming process at high speed, a paper post-processing apparatus capable of high-speed processing capable of performing a function following the processing speed is required.
[0005]
With regard to such a sheet post-processing apparatus, JP-A-60-142359, JP-A-60-158463, JP-A-62-239169, JP-A-62-228802, JP-A-62-267667, JP-A-2-276661. No. 8, JP-A-8-319054 and JP-B-5-41991.
[0006]
A bookbinding apparatus disclosed in Japanese Patent Application Laid-Open No. 60-183459 has a cover sheet supply device, and performs bookbinding finishing operations such as punching or stapling after the copy paper group and the cover sheet are overlapped.
[0007]
JP-A-6-72064, JP-A-7-187479, and JP-A-8-192951 are paper post-processing apparatuses having a saddle stitching processing function.
[0008]
[Problems to be solved by the invention]
The conventional paper post-processing apparatus has the following problems.
[0009]
A sheet comprising a pair of folding rollers that press and fold the center of the sheet bundle in the conveying direction, and a folding sheet member that projects toward the fold portion of the sheet bundle while moving toward the clamping position of the pair of folding rollers. In the center folding means, the front end of the center folding plate member is advanced, and the fold portion of the sheet bundle is protruded and sandwiched at the sandwiching position of the normally rotating pair of center folding rollers, so that the sheet bundle is folded in half. I was processing.
[0010]
However, the fold portion of the sheet bundle after passing through the nipping position of the pair of folding rollers that are driven to rotate tends to expand due to the residual stress of the sheet, and the folded sheet bundle becomes thick and thick. In particular, in a sheet bundle having a large number of sheets, the swelling of the sheet bundle is remarkable, and the finished appearance quality of the sheet bundle is deteriorated.
[0011]
[Means for Solving the Problems]
The above problems in the middle folding process are solved by the following method and apparatus.
[0012]
(1) After the central portion in the transport direction of the sheet bundle conveyed on the paper stacking portion is pressed by the intermediate folding plate member of the paper ejecting means into the sandwiching position of the pair of the middle folding rollers to form the middle folding portion, In a sheet post-processing method in which the folded portion of the sheet bundle is pressed and discharged by a pair of pressure rollers, the leading end of the folded portion reaches a predetermined position beyond the clamping position of the folded pair of the folded rollers. The middle folding plate member is detached from the middle folding portion of the sheet bundle, and the middle folding roller pair and the pressure roller pair are driven and rotated, and then stopped, in the vicinity of the front end portion of the middle folding portion. Is held between the pressure roller pair for a predetermined time, and then the pair of folding rollers and the pressure roller pair are driven and rotated to discharge the sheet bundle.
[0013]
(2) The central portion in the conveyance direction of the sheet bundle conveyed on the sheet stacking portion is pushed into the clamping position of the pair of folding rollers while being pressed by the sheet ejecting means to form the folded portion, and then the pair of pressure rollers In the sheet post-processing apparatus that pressurizes and discharges the folded portion of the sheet bundle, the first driving means for driving the folded sheet member of the sheet ejecting means, the pair of folding rollers, and the pressure roller pair are driven. Second driving means for rotating; tip end position control means for stopping the tip end portion of the half-folded portion at a predetermined position beyond the clamping position of the pair of pressure rollers; the first driving means and the second driving means; Drive control means for controlling the drive of the sheet bundle, and the middle folding portion of the sheet bundle for a predetermined time from the time when the tip of the middle folding portion reaches a predetermined position beyond the clamping position of the pair of pressure rollers. Near the pressure roller pair A sheet post-processing apparatus that discharges the sheet bundle by driving and rotating the pair of half-folding rollers and the pair of pressure rollers after being held in a state of being held between the sheets.
[0014]
(3) A sheet post-processing apparatus having the half-folded plate member, the middle folding roller pair, the pressure roller pair, the first driving means, the second driving means, the tip position control means, and the driving control means according to (2) And an image forming apparatus main body comprising an image forming unit and a sheet conveying unit.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the sheet post-processing apparatus of the present invention will be described with reference to the accompanying drawings.
[0016]
[One Embodiment of Image Forming Apparatus]
FIG. 1 is an overall configuration diagram of an image forming system including an image forming apparatus main body A, an image reading apparatus B, and a paper post-processing apparatus (hereinafter referred to as a post-processing apparatus) C.
[0017]
The image forming apparatus main body A has a charging unit 2, an image exposure unit (writing unit) 3, a developing unit 4, a transfer unit 5A, a neutralizing unit 5B, around a rotating image carrier (hereinafter referred to as a photoreceptor) 1. And an image forming unit provided with a cleaning unit 6. The image forming unit uniformly charges the surface of the photoreceptor 1 by the charging unit 2 and then performs exposure scanning based on image data read from the document by the laser beam of the image exposure unit 3 to form a latent image. The latent image is reversely developed by the developing means 4 to form a toner image on the surface of the photoreceptor 1.
[0018]
On the other hand, transfer paper (hereinafter referred to as paper) S fed from the paper storage means 7A is sent to the transfer position. The toner image is transferred onto the paper S by the transfer means 5A at the transfer position. Thereafter, the charge on the back surface of the sheet S is erased by the charge removing unit 5B, separated from the photoreceptor 1, conveyed by the intermediate conveying unit 7B, heated and fixed by the fixing unit 8, and discharged from the sheet discharging unit 7C.
[0019]
When image formation is performed on both sides of the sheet S, the sheet S heated and fixed by the fixing unit 8 is branched from the normal sheet discharge path by the conveyance path switching plate 7D, and is switched back in the reverse conveyance section 7E. After the reversal, it passes through the image forming unit again, forms an image on the back surface of the paper S, and is discharged from the paper discharge unit 7C to the outside of the apparatus via the fixing unit 8. The paper S discharged from the paper discharge unit 7C is sent to the receiving unit 11 of the post-processing apparatus C.
[0020]
On the other hand, the developer remaining on the surface of the photoreceptor 1 after the image processing is removed by the cleaning unit 6 to prepare for the next image formation.
[0021]
On the upper part of the image forming apparatus main body A, an image reading apparatus B equipped with an automatic document feeder of a document moving type reading system is installed.
[0022]
[Configuration of paper post-processing device]
The post-processing apparatus C connected to the image forming apparatus main body A includes an entrance conveyance unit 10, a shift processing unit 20, a binding processing unit 30, a stapling unit (binding unit) 40, a cover sheet feeding unit 50, a center folding processing unit 60, and A paper discharge unit 80 is included.
[0023]
The entrance transport unit 10 transports the paper S discharged from the image forming apparatus main body A to each processing unit. The shift processing unit 20 sorts the paper S conveyed from the inlet conveyance unit 10 into a shift process, and discharges the paper S to an elevating paper discharge tray 82 described later. The binding processing unit 30 stacks the sheets S transported from the entrance transport unit 10 and performs a saddle stitching process or an end binding process by a stapling unit 40 described later. The middle folding processing unit 60 performs a middle folding process for folding the central portion of the paper S in the paper conveyance direction, and discharges it to a lower paper discharge tray 83 to be described later. The cover sheet feeding unit 50 feeds a cover sheet (hereinafter referred to as a cover sheet) K and transports it to the shift processing unit 20 or the binding processing unit 30.
[0024]
The paper discharge unit 80 includes a top discharge table 81 that directly discharges and stores the paper S discharged from the image forming apparatus main body A via the entrance conveyance unit 10 without performing post-processing, and shift processing or edge binding. There is an elevating / discharging tray 82 for storing the processed sheet bundle, and a lower discharge tray 83 for storing the folded sheet bundle.
[0025]
[Paper transport path and upper mechanism of post-processing apparatus C]
FIG. 2 is a schematic diagram showing a paper conveyance path of the post-processing apparatus C, and FIG. 3 is a cross-sectional view showing an upper mechanism of the post-processing apparatus C.
[0026]
The post-processing apparatus C is installed with its position and height adjusted so that the receiving section 11 for the paper S carried out from the image forming apparatus main body A matches the paper discharge section 7C of the image forming apparatus main body A.
[0027]
The conveyance path of the paper S connected downstream of the inlet roller pair 12 of the receiving section 11 in the paper conveyance direction is the upper first conveyance path (1), the middle second conveyance path (2), and the lower third conveyance path. Branching into three systems {circle around (3)}, the sheet S is fed to any one of the transport paths by selecting the angle occupied by the switching means G1 and G2.
[0028]
・ (Discharged to the upper output tray 81)
The image-formed paper S discharged from the image forming apparatus main body A is introduced into the receiving unit 11 and conveyed by the inlet roller pair 12, and the conveyance direction length of the paper S is detected by the inlet sensor PS1 for detecting passage of the inlet. Is detected. The sheet S passes through the right passage 13 of the upper first switching means G1, is sandwiched and transported between the driving roller 14A and the driven roller 14B of the upper transport roller pair 14, and is further sandwiched by the transport roller pair 15. After being conveyed, the sheet is sandwiched between the discharge roller pair 16 and is discharged onto the upper sheet discharge table 81 at the upper part outside the apparatus and sequentially stacked (first conveyance path (1)).
[0029]
In this sheet conveyance process, the switching means G1 is swung by the drive of the solenoid SD1, closes the passage 17, opens the passage 13, and allows the sheet S to pass through the upper sheet discharge table 81.
[0030]
The upper sheet discharge table 81 can accommodate a maximum of about 200 sheets S, and the operator can easily take it out from the upper portion of the post-processing apparatus C.
[0031]
・ (Shift processing or non-sorting)
When this transport mode is set, the switching means G1 closes the passage 13 and keeps the passage 17 open while the solenoid SD1 is off, allowing the paper S to pass through the passage 17.
[0032]
The image-formed paper S discharged from the image forming apparatus main body A passes through the receiving portion 11 and the inlet roller pair 12, passes through the passage 17 formed in an open state below the switching means G1, and is conveyed. Passed between the pair of rollers 18 and passed through the passage 21 above the second switching means G2 that is obliquely below the second transport path (2), and is sandwiched by the pair of transport rollers 22 and transported through the passage 23. It is sandwiched between a pair of rollers (shift roller pair) 24 and is discharged and placed on an up-and-down discharge tray 82 by a discharge roller pair 26 composed of an upper roller 26A and a lower roller 26B (second transport path ▲ 2). ▼). Reference numeral 27 denotes a swinging means for swinging the upper roller 26A so as to be sandwiched and separated from the lower roller 26B.
[0033]
A maximum of about 3000 sheets of paper S can be accommodated in the elevating / discharging tray 82.
[0034]
[End binding processing]
The image-formed sheet S that has been subjected to image formation processing in the image forming apparatus main body A and sent to the receiving section 11 of the post-processing apparatus C is a passage 17 below the inlet roller pair 12 and the first switching means G1. , Is sandwiched between the pair of transport rollers 18 and is transported to the third transport path (3).
[0035]
In the third transport path (3), when a paper S of a size larger than A4 size and B5 size is transported, the solenoid SD2 is driven, and the paper S passes through the passage 31A below the switching means G2 and reaches the downstream side. It is sandwiched and transported by the transport roller pair 32. The sheet S is sandwiched and sent out by a pair of conveying rollers 34 including a driving roller 34A and a driven roller 34B further downstream, and is discharged to an upper space of the intermediate mounting table 35 that is inclined, so that the intermediate mounting table 35 or the intermediate mounting table 35 is discharged. After touching the upper surface of the paper S stacked on the table 35 and sliding up, the trailing edge of the paper S in the advancing direction is discharged from the conveying roller pair 34. The sheet S slides down on the inclined surface of the mounting table 35, and the leading end of the sheet S in the advancing direction comes into contact with the sheet abutting surface of the end binding abutting member 41 near the stapling means 40 and stops.
[0036]
In the third transport path (3), in order to improve the copy productivity by efficiently transporting a small size paper S of A4 size, B5 size, etc., to the passage 31A below the switching means G1. Parallel passage 31B and switching means G3 were provided.
[0037]
When the solenoid SD2 for the switching means G2 and the solenoid SD3 for the switching means G3 are driven together, the tips of the switching means G2 and G3 both swing counterclockwise as shown in the figure, closing the passages 21 and 31A, Open the passage 31B.
[0038]
The leading end portion of the first sheet S sent out from the conveying roller pair 18 passes through the passage 31B and comes into contact with the peripheral surface of the conveying roller pair 34 in the rotation stopped state to stop.
[0039]
Next, the energization of the solenoid SD3 is turned off, the tip of the switching means G3 is swung clockwise, the passage 31B is closed, and the passage 31A is opened. The leading edge of the second sheet S sent out from the conveying roller pair 18 passes through the passage 31A and comes into contact with the peripheral surface of the conveying roller pair 34 in the rotation stopped state to stop.
[0040]
At a predetermined timing, the transport roller pair 34 is driven and rotated, and the two sheets S are sandwiched and transported at the same time, and discharged onto the intermediate mounting table 35. The third and subsequent sheets are discharged one by one.
[0041]
Reference numeral 36 denotes an upstream side width aligning means comprising a pair of width aligning members provided on both side surfaces of the intermediate mounting table 35. At least one width aligning member of the upstream side width aligning means 36 is movable in a direction orthogonal to the sheet transport direction, and is opened wider than the sheet width when the sheet S is discharged onto the intermediate mounting table 35, When sliding on the intermediate mounting table 35 and coming into contact with the end binding abutting member 41 to stop, the side edges in the width direction of the sheets S are tapped to perform width alignment (width alignment) of the sheet bundle. At this stop position, when a predetermined number of sheets S are stacked and aligned on the intermediate mounting table 35, the stapling means 40 performs a binding process, and the sheet bundle is bound.
[0042]
A cutout portion is formed in a part of the sheet stacking surface of the intermediate mounting table 35, and a plurality of discharge belts 38 wound around the drive pulley 37A and the driven pulley 37B are driven to be rotatable. A discharge claw 38 a is integrally formed on a part of the discharge belt 38, and the tip of the discharge belt 38 draws an elliptical locus as shown by a one-dot chain line in the drawing. The stapled sheet bundle is held on the trailing edge of the sheet S by the discharge claw 38a of the discharge belt 38, is placed on the discharge belt 38, slides on the placement surface of the intermediate placement table 35, and obliquely upwards. To the clamping position of the discharge roller pair 26. The sheet bundle sandwiched between the rotating discharge roller pair 26 is discharged and stacked on the lifting / lowering discharge table 82.
[0043]
[Cover Feed]
The cover sheet feeding unit 50 is configured by a cover sheet placing unit including a sheet feeding tray 51, a movable bottom plate 52, and a push-up lever 53, and a cover sheet feeding unit including a feeding roller 54, a sheet feeding roller 55, a separating roller 56, and the like. ing.
[0044]
One cover sheet K fed from the cover sheet feeding section 50 passes through the passage 57, passes through the nipping position between the driving roller 14A and the driven roller 14C of the transport roller pair 14, and passes through the passage 19 and the transport roller pair. After passing through 18, it reaches the intermediate mounting table 35 through the conveying roller pair 32, the passage 33, and the conveying roller pair 34 in the third passage (3).
[0045]
The conveying roller pair 14 includes a central driving roller 14A and two driven rollers 14B and 14C that are in pressure contact with the driving roller 14A. When the driving roller 14A is driven to rotate counterclockwise, the driven roller 14B rotates to the right and conveys the sheet S conveyed from the passage 13 upward. At the same time, the driven roller 14 </ b> C also rotates to the right to convey the cover sheet K conveyed from the passage 57 to the lower passage 19. Accordingly, the sheet S in the first conveyance path (1) and the cover sheet K in the fourth conveyance path (4) can be simultaneously conveyed in the opposite directions by the driving rotation of the drive roller 14A.
[0046]
[Saddle stitching]
FIG. 4 is a cross-sectional view showing the staple processing unit and the center folding processing unit of the post-processing apparatus C.
[0047]
The stapling means 40 has a two-part structure of an upper mechanism 40A and a lower mechanism 40B, and a passage 42 through which the paper S can pass is formed in the middle.
[0048]
Two sets of stapling means 40 are arranged in a direction orthogonal to the paper conveyance direction, and can be moved in a direction orthogonal to the paper conveyance direction by a driving means (not shown). By this stapling means 40, staples SP are hit at two central sorting positions in the paper width direction (see FIG. 6A).
[0049]
When the saddle stitching mode is set, the end binding abutting member 41 in the vicinity of the staple processing position of the stapling means 40 is retracted from the fifth conveyance path (5), and substantially at the same time downstream from the abutting member 43 for saddle stitching. Is activated to block the passage 42 (see FIG. 2).
[0050]
When the size (length in the transport direction) of the cover sheet K and the sheet S is set or detected, the saddle stitch abutting member 43 moves to a predetermined position and stops.
[0051]
After the cover sheet K is placed at a predetermined position on the intermediate placement table 35, the sheet S carried out from the image forming apparatus main body A passes through the third conveyance path (3) from the inlet conveyance section 10 of the post-processing apparatus C. Then, the sheets are sequentially stacked on the upper surface of the cover sheet K placed on the intermediate placing table 35, and the end portion of the sheet S is brought into contact with the saddle stitching abutting member 43 and positioned. The downstream side width aligning means 46, which is composed of a pair of width aligning members that regulate the width direction of the paper S during the saddle stitching process, is similar to the upstream side width aligning means 36 every time one paper S is carried in. Tap the side edges in the width direction to perform width alignment.
[0052]
The upstream side width aligning unit 36 and the downstream side width aligning unit 46 selectively perform width aligning driving according to the setting of the end binding process or the saddle stitching process. That is, only the upstream width aligning means 36 is driven during the end binding process, and the downstream width aligning means 46 is not driven. During the saddle stitching process, the upstream side width matching unit 36 and the downstream side width matching unit 46 are driven. During the saddle stitching process, the downstream side width aligning unit 46 is driven later than the upstream side width aligning unit 36.
[0053]
Further, during the saddle stitching process, the upstream side width aligning unit 36 first performs width alignment on the sheet S conveyed on the intermediate mounting table 35 and traveling upstream of the stapling unit 40, and then aligns the sheet. Then, the downstream side width aligning means 46 performs the width alignment on the sheet S that passes through the staple means 40 and proceeds toward the saddle stitching abutting member 43 to align the sheets. In this way, the sheet S and the cover sheet K that travel on the intermediate mounting table 35 and extend over the upstream side and the downstream side with the staple unit 40 as the center are stacked with the upstream side width aligning unit 36 and the downstream side. With the side width aligning means 46, the width is accurately aligned over the entire length of the sheet S.
[0054]
After the final sheet S is positioned and placed on the intermediate placing table 35, the saddle stitching process by the stapling means 40 is performed on the sheet bundle composed of the cover sheet K and all the pages of the sheet S. By the saddle stitching process, the staple needle SP is driven into the center portion in the transport direction of the cover sheet K and the sheet S. The staple needle SP is driven from the lower mechanism 40B having the staple needle driving drive side toward the upper mechanism 40A having the staple needle bending side.
[0055]
[Folding process]
After the saddle stitching process, the saddle stitch abutting member 43 swings to open the passage downstream of the passage 42. The sheet bundle composed of the cover sheet K and the sheet S subjected to the saddle stitching process is conveyed by being guided by the guide plate 63 on the conveyance belt 62 obliquely below through the curved path and the intermediate conveyance roller pair 61, and (2) The sheet is conveyed on the sheet stacking unit (stack base) 64, and the leading end of the sheet bundle in the conveying direction is brought into contact with the folding unit abutting member 650, which is a positioning member of the folding unit movable abutting means 65, so Stop (sixth conveyance path (6) shown in FIG. 2). The folding portion abutting member 650 can be moved to a predetermined position by setting or detecting the paper size and driving means.
[0056]
A sheet ejecting means 66 is installed at the center of the stopped sheet bundle in the conveying direction, that is, obliquely below the saddle stitching position. A half-fold forming part 67 and a pressurizing part 68 are installed obliquely above the saddle stitching position.
[0057]
The middle folding processing unit 60 includes a sheet ejecting unit 66, a middle folding forming unit 67, a pressure unit 68, and the like.
[0058]
In response to the middle folding start signal, a middle folding plate member (hereinafter referred to as a middle folding knife) 661 which is a movable ejection plate of the paper ejection means 66 advances obliquely upward, and the leading end of the middle folding knife 661 has a cover K. The central portion of the sheet bundle made up of the sheets S is pushed up, and the sandwiching portion of the pair of folding rollers 671 driven to rotate through the bundle of sheets is pushed open to swing and separate.
[0059]
After the leading end of the middle folding knife 661 passes through the clamping part, the middle folding knife 661 moves backward, and the central part of the sheet bundle is pinched by the middle folding forming part 67 to form a fold. This fold line substantially coincides with the driving position of the staple needle SP on the sheet bundle by the saddle stitching process.
[0060]
The central portion of the sheet bundle formed with a fold by being clamped by a pair of middle folding rollers 671A and 671B (hereinafter referred to as a pair of middle folding rollers 671) rotated by the middle folding forming portion 67 is sent to the pressing portion 68. Accordingly, the crease is pressed more strongly at the holding position of a pair of pressure rollers 681A and 681B (hereinafter referred to as pressure roller pair 681).
[0061]
The fed sheet bundle is nipped and conveyed by the pressurizing unit 68 and discharged onto the lower sheet discharge tray 83 outside the apparatus (seventh conveyance path shown in FIG. 2).
[0062]
FIG. 5 is a schematic diagram showing the conveyance path of the cover sheet K and the sheet S, the saddle stitching and center folding process of the sheet bundle, and FIG. 6A shows two central distribution points along the fold part a where the sheet S is folded. FIG. 6B is a perspective view of a sheet bundle subjected to saddle stitching and center folding post-processing, and FIG. 6C is post-processed. FIG.
[0063]
On the sheet feeding tray 51 of the cover sheet feeding unit 50, the cover sheet K is placed with the first side (first page p1 and eighth page p8) facing upward. The cover sheet K fed from the sheet feeding tray 51 by the sheet feeding means is transported through the fourth transport path {circle over (4)} and the third transport path {circle around (3)} on the intermediate mounting table 35. The surface (p1, p8) is placed on the lower side.
[0064]
Next, the image-formed sheet S carried out from the image forming apparatus main body A is introduced into the post-processing apparatus C with the first side (the third page p3 and the sixth page p6) facing down. The sheet S is transported from the entrance transport section 10 to the third transport path (3), and is placed on the cover sheet K placed on the intermediate placing table 35 with the first surface facing down.
[0065]
The cover sheet K and the sheet are aligned on the intermediate mounting table 35, and the staple needle SP is driven by the stapling means 40 to perform saddle stitching.
[0066]
The sheet bundle subjected to the saddle stitching process passes through the fifth conveyance path (5), is placed at a predetermined position on the second sheet stacking unit 64 and the conveyance belt 62, and stops. At this time, the sheet bundle is placed in a state where the sheet S has the first side (p3, p6) on the upper side and the cover sheet K thereon has the first side (p1, p8) on the upper side.
[0067]
Next, the folding operation is performed by the push-up operation of the sheet ejecting means 66 and the rotation of the pair of folding rollers 671. Subsequently, the folding process is performed, and the sheet is sandwiched and transported by the pressurizing unit 68, and is To be discharged.
[0068]
A sheet bundle (booklet) produced by the saddle stitching process and the middle folding process has the first side (p1, p8) of the cover K facing outward, the second side (p2, p7) on the back side, and further on the inside The first side (p3, p6) of the sheet S, which is the contents, and the second side (p4, p5) of the sheet S are arranged on the inner side, and a booklet page consisting of eight pages (p1 to p8) as shown in the figure. Can be aligned.
[0069]
When the booklet production auto mode is selected and set in the operation unit of the image forming apparatus main body A, the cover K is loaded on the sheet feeding tray 51, and printing is started, the control unit of the image forming apparatus main body A performs the above-described image. The process is executed, and the sheet S carrying the image is subjected to the saddle stitching process and the center folding process by the post-processing apparatus C, and a booklet is continuously produced and discharged.
[0070]
In the operation section of the post-processing apparatus C, the booklet production manual mode is selected and set, and the cover sheet K and a sheet of paper S on which an image has been formed are stacked on the sheet feeding tray 51, and the feeding operation is performed. When started, the control means 90 (see FIG. 17 described later) of the post-processing apparatus C performs a saddle stitching process and a center folding process on the cover sheet K and the sheet S to produce and discharge one booklet. Is done.
[0071]
FIG. 7 is a cross-sectional view of the middle folding processing unit 60 including the folding unit movable abutting unit 65, the sheet ejection unit 66, the middle folding forming unit 67, and the pressing unit 68. FIG. 8 is a perspective view of the half-fold processing unit 60.
[0072]
The folding portion movable abutting means 65 contacts the leading end portion of the sheet bundle of various sizes conveyed on the second sheet stacking portion 64 and positions the leading end portion. The folding portion abutting member 650 is fixed to the holding member 651. The holding member 651 is driven by the motor M1, and slides on the rod-shaped guide member 652 to linearly move. The actuator 653 and the folding part sensor PS2 detect the passage of the leading end of the sheet S conveyed on the second sheet stacking unit 64.
[0073]
The control unit 90 reciprocates the folding unit abutting member 650 in the conveyance direction of the sheet bundle by the driving unit in accordance with the timing when the leading end of the sheet bundle in the conveyance direction contacts the folding unit abutting member 650. Make sure to align the tip.
[0074]
After the leading edge of the paper S is aligned, the movable holding member 662 moves straight along the rod-shaped guide member 663 that is fixedly arranged in response to the middle folding start signal, and the middle folding knife 661 fixed to the movable holding member 662 is placed on the paper. Projects upward from the mounting surface. The half-folding knife 661 has a thin plate shape such as a stainless steel plate, and the tip thereof forms an acute angle. The front end portion of the half-folding knife 661 is formed on a low friction surface and is subjected to surface treatment such as gloss finish or fluororesin coating.
[0075]
One pressing means of the half-fold forming portion 67 includes a half-fold roller 671A that is driven by being connected to a drive source, and a support that can pivot about the support shaft 673A. The movable member 672A is a member, and a spring 674A that is locked to one end of the movable member 672A and biases the half-folding roller 671A in the clamping position direction.
[0076]
The other pressing means of the half-fold forming portion 67 has the same configuration and includes a half-fold roller 671B, a movable member 672B, a support shaft 673B, and a spring 674B.
[0077]
A pressurizing unit 68 is disposed on the downstream side of the center folding forming unit 67 in the sheet conveying direction. The pressure unit 68 is composed of a pressure roller pair 681 (second intermediate folding roller pair) driven by being connected to a drive source.
[0078]
The pair of pressure rollers 681A and 681B has a rubber coating layer. For example, the rubber coating layer is formed from an elastic material such as ethylene-propylene rubber (EPDM).
[0079]
When the pressure roller pair 681 is a metal roller, when the rear end of the sheet bundle passes through the holding position of the pressure roller pair 681, a striking sound is generated due to the collision of the metal rollers. In addition, it is effective for holding one of the pressure roller pairs 681 to be a hard roller made of metal or the like for maintaining a uniform pressure during the folding process.
[0080]
The sheet bundle formed with the fold portion a (see FIG. 6A) by being pressed by the rotating pair of middle folding rollers 671 is sent to the holding position of the pressure roller pair 681, and the fold portion a is at this position. Further, the pressure is increased and the sheet is discharged to a lower discharge tray 83 outside the apparatus.
[0081]
・ (Folding roller drive mechanism)
FIG. 9 is a configuration diagram of the middle folding roller pair 671, the pressure roller pair 681, and the middle folding roller driving unit (second driving unit) 670 that drives the middle folding processing unit 60 shown in FIG. .
[0082]
The motor M2 rotates a pulley P1 having a two-stage configuration that is rotatably supported by an intermediate shaft via a timing belt (hereinafter referred to as a belt) B1. A belt B2 is stretched around the pulley P1, and the pulley P2 is rotated. The pulley P2 rotates the driving roller 611 of the intermediate conveyance roller pair 61 via the belt B3.
[0083]
The belt B2 around which the pulley P2 is wound is wound around the pulleys P3 and P4 of the intermediate shaft and the pulley P5 fixed to the shaft end of the pressure roller 681B and is simultaneously rotated. P6 and P7 are tension pulleys.
[0084]
The driving roller 621 fixed on the rotation shaft of the pulley P2 rotates the conveyance belt 62 stretched between the driving roller 621 and the driven roller 622.
[0085]
The intermediate shaft pulley P3 rotates the pulley P8 fixed to the shaft end of the center folding roller 671A via the belt B4. The pulley P4 of the intermediate shaft rotates the pulley P9 fixed to the shaft end of the center folding roller 671B via the belt B5.
[0086]
A one-way clutch CA is built in the pulley P8 at the shaft end of the center folding roller 671A. A one-way rotation clutch CB is built in the pulley P9 at the shaft end of the center folding roller 671B.
[0087]
The gear g1 fixed to the shaft end of the pressure roller 681B is connected to the gear g4 via gears g2 and g3 rotatably supported at a fixed position of the panel of the apparatus main body.
[0088]
The gear g3 is rotatably supported by a support shaft 689 implanted in the panel of the apparatus main body. The gear g4 is fixed to the shaft end of the pressure roller 681A supported by the swing plate 687.
[0089]
The two swing plates 687 are swingably supported at both shaft ends of the support shaft 689 to which the gear g3 is fixed, and are biased by a spring 688. Both shaft ends of the pressure roller 681A to which the gear g4 is fixed are rotatably supported by the swing plate 687.
[0090]
The pressure roller 681A supported by the swing plate 687 swings about the support shaft 689, is urged by a spring 688, and presses against the pressure roller 681B.
[0091]
・ (Drive mechanism for half-folded plate member)
FIG. 10 is a plan view of the folding knife driving means (first driving means) 660 for moving the folding knife 661. Since the sheet ejecting means 66 is symmetric with respect to the center line CL shown in the drawing, a part of the drawing is omitted. FIG. 11 is a cross-sectional view of the half-fold knife driving means (first driving means) 660. 10 and 11 show a state immediately before the sheet bundle is folded in half.
[0092]
The motor M3 rotates the large-diameter gear g8 via the gears g5, g6, and g7. The gear g8 is rotatably supported on a support shaft 665 implanted in the fixed substrate 667. An eccentric cylindrical member 664 is integrally formed at the bottom of the gear g8. The annular recess 664A drilled in the eccentric cylindrical member 664 performs an eccentric motion around the eccentric shaft 664B different from the rotation center of the support shaft 665 by the rotation of the gear g8.
[0093]
A roller 666 planted on the movable holding member 662 is movably transferred to the inner wall portion of the annular recess 664A. Reference numeral 666A denotes a movement locus of the center of the roller 666.
[0094]
The movable holding member 662 is supported so as to be capable of rectilinear reciprocation along two guide members 663 arranged in parallel to the fixed substrate 667. The rotation of the gear g8 causes the annular recess 664A to move eccentrically, whereby the roller 666 moves along the inner wall of the annular recess 664A and causes the movable holding member 662 to reciprocate linearly along the two guide members 663. . The folding knife 661 fixed to the movable holding member 662 also reciprocates linearly at the same time.
[0095]
・ (Paper folding process)
FIG. 12 is a cross-sectional view showing a state in which the folded portion of the sheet S passes through the folded portion 67.
[0096]
As the motor M3 starts to be driven, the folding knife 661 held by the movable holding member 662 moves forward. The front end portion of the center folding knife 661 projects a fold portion a at the center of the sheet S in the sheet transport direction, and feeds it to the clamping position X of the pair of center folding rollers 671 that has stopped rotating. A middle fold is formed.
[0097]
When the leading end of the center folding knife 661 protrudes from the folded portion of the sheet S and slides into contact with the outer peripheral surface of the center folding roller pair 671 and feeds it to the clamping position X, it is provided at each shaft end of the center folding roller pair 671. Further, the half-folding roller pair 671 is rotated with the moving sheet S by the one-way rotation clutches CA and CB, and is driven to rotate only in the sheet conveying direction.
[0098]
The front end of the center folding knife 661 advances to the maximum pressing position Y slightly beyond (0.5 to 10 mm) from the clamping position X of the pair of center folding rollers 671 to push the sheet S into the center folded state, and then returns. To start. During the returning operation of the front end of the center folding knife 661, after the center folding section of the sheet S passes the clamping position X of the center folding roller pair 671, the motor M2 starts to be driven, and the center folding roller pair 671 is driven to rotate. Let it begin.
[0099]
The middle folding knife 661 continues to return, the leading end of the middle folding knife 661 is pulled out from the folding section of the paper S, and the folding section of the paper S is sandwiched and held on the outer peripheral surface of the pair of middle folding rollers 671. The crease is strongly attached.
[0100]
When the leading end of the folding knife 661 is pulled out from the folding portion of the sheet S, the pair of middle folding rollers 671 is prevented from reversing by the one-way rotation clutches CA and CB, so that the sheet S does not move backward. .
[0101]
The above is the basic operation of the middle folding process. Details of the sheet post-processing apparatus of the present invention for improving folding performance will be described in detail in first to fourth embodiments described later.
[0102]
・ (Pressurizing paper)
FIG. 13 is a cross-sectional view showing a state in which the sheet S subjected to the folding process passes through the pressurizing unit 68.
[0103]
The leading edge of the sheet S that has passed through the nipping position of the rotating half-folding roller pair 671 is sent to the nipping position of the rotating pressure roller pair 681. The leading edge of the sheet S is sandwiched between a pressure roller 681B that rotates at a fixed position and a pressure roller 681A that is rotatably supported by a rocking plate 687 and is further creased.
[0104]
The movable member 672A is swingably supported around the support shaft 673A and is biased by a spring 674A. The swing plate 687 is supported so as to be swingable about the support shaft 689 and is urged by a spring 688.
[0105]
The bundle of folded sheets conveyed while being sandwiched between the pair of middle folding rollers 671 is pushed between the pair of pressure rollers 681 with a wide roller interval, and is sandwiched between the pair of pressure rollers 681 so that the folds are firmly attached. Thereafter, the sheet is smoothly conveyed regardless of the thickness of the sheet bundle.
[0106]
・ (Paper ejection)
FIG. 14 is a cross-sectional view illustrating a state in which the folded and pressurized paper is discharged.
[0107]
The leading edge of the sheet S that has passed through the clamping position of the rotating pressure roller pair 681 is carried out of the apparatus. When the rear end portion of the sheet S passes, it returns to the initial state in which the pair of folding rollers 671 is closed, and the leading end portions of the movable members 672A and 672B come into contact with the elastic stop member 678 and stop.
[0108]
The half-folding roller pair 671 and the pressure roller pair 681 are not limited to each pair, and any number of pairs may be arranged as necessary.
[0109]
[First embodiment of sheet folding control]
FIG. 15 is a diagram for explaining the middle folding process of the paper S. FIG. 16 is a timing chart of the process of folding the sheet S in half, and FIG. 17 is a block diagram showing the control of the post-processing apparatus. Hereinafter, control of the process of performing the folding process on the sheet S by the control unit 90 will be described.
[0110]
When a sheet size signal, a sheet number signal, a saddle stitching designation signal, and a saddle folding designation signal are input to the operation unit of the image forming apparatus main body A, the control unit 90 controls the execution of the saddle stitching and folding process.
[0111]
In the post-processing apparatus C, the passage of the sheet S is detected by the entrance part sensor PS1, the folding part sensor PS2, and the paper discharge part sensor PS3. The HP sensor PS4 detects the initial position of the center folding knife 661.
[0112]
(1) FIG. 15A shows an initial state before the middle folding process is started.
The arm 672A that supports the middle folding roller 671A and the arm 672B that supports the middle folding roller 671B are arranged symmetrically so that the middle folding knife 661 is inserted into the clamping position X of the middle folding roller pair 671, and the spring 674A and 674B are equally urged and held in a stopped state by a stop member 678. In this stopped state, the distal ends of the arms 672A and 672B abut against the stop member 678 so that the outer peripheral surfaces of the pair of folding rollers 671 are close to each other or lightly contact each other (see FIG. 14). In this initial state, the half-folding knife 661 is stopped at the standby position W.
[0113]
(2) FIG. 15B shows a state in which the leading end of the paper S passes through the clamping position X of the half-fold forming portion 67.
[0114]
When the drive of the motor M3 (see FIGS. 10 and 11) starts, the folding knife 661 moves forward. The front end portion of the center folding knife 661 projects a fold portion a (see FIG. 6A) that is the central portion in the sheet transport direction of the sheet S, and the center folding roller pair 671 is driven to rotate and sent to the clamping position X. The sheet S is folded in half.
[0115]
(3) FIG. 15C shows a state in which the leading edge of the paper S has reached the maximum pushing position Y beyond the clamping position X.
[0116]
The center folding knife 661 is further driven forward by the motor M3, presses the center folding portion of the sheet S, and reaches the maximum pushing position Y beyond the nipping position X of the pair of center folding rollers 671 to be driven to rotate. The leading end portion of the sheet S is nipped and conveyed by the folding knife 661 and the folding roller pair 671 to form a fold portion a (see FIGS. 12 and 6A).
[0117]
(4) FIG. 15D shows a state in which the middle folding portion of the paper S is pressed by the middle folding roller pair 671 and the middle folding knife 661 returns to the standby position W.
[0118]
Reaching the maximum pushing position Y of the center folding knife 661 is controlled by an HP sensor that detects an initial position (home position) HP of the center folding knife 661 and a timer. The pair of middle folding rollers 671 keeps a stopped state from when the middle folding knife 661 reaches the maximum pushing position Y until a predetermined time t2 from the timer elapses, and presses the middle folding portion of the paper S strongly. The predetermined time t2 until the driven rotation of the pair of folding rollers 671 is stopped and the driving rotation is started is set within a range of 1 to 10 seconds.
[0119]
In a state where the pair of middle folding rollers 671 presses and holds the vicinity of the leading end of the middle folding portion of the paper S, the middle folding knife 661 moves backward and separates from the middle folding portion of the paper. When the half-fold plate member 661 moves backward and separates from the middle folding section of the sheet instead of using the one-way rotation clutches CA and CB, the middle folding roller pair 671 is temporarily driven forward so that the sheet S is in the middle. In response to the retraction of the folding knife 661, the retraction from the maximum pushing position Y may be prevented.
[0120]
(5) FIG. 15E shows the conveyance of the sheet S by the pair of folding rollers 671.
Rotation of the motor M2 is started after a predetermined time t1 from the time when the middle folding knife 661 reaches the maximum pushing position Y, that is, after the predetermined time t1 has elapsed after the middle folding knife 661 passes the initial position HP. Then, the forward rotation drive of the half-fold roller pair 671 and the pressure roller pair 681 is started. The pair of intermediate folding rollers 671 pinches the sheet S that has been subjected to the middle folding process, and conveys the sheet S to the holding position of the pressure roller pair 681.
[0121]
(6) FIG. 15 (f) shows a state in which the sheet S is conveyed while being sandwiched between the pair of folding rollers 671 and the pressure roller pair 681.
[0122]
The sheet S that has been subjected to the middle folding process by the middle folding roller pair 671 and is conveyed passes through the nipping position of the pressure roller pair 681.
[0123]
After the fact that the half-folding knife 661 has passed the initial position HP is detected by the HP sensor PS4 (see FIG. 17), the driving of the motor M2 is temporarily stopped after a predetermined time t3 by the timer. With this driving stop, the leading edge of the paper S is stopped at a temporary stop position Z beyond the clamping position of the pressure roller pair 681. The temporary stop position Z is 0.5 to 10 mm downstream from the holding position of the pressure roller pair 681.
[0124]
The pressure roller pair 681 maintains the stopped state until a predetermined time t4 has elapsed from the time when the driving of the motor M2 is stopped, and presses the folded portion of the sheet S strongly. The predetermined time t4 by the timer until the driving rotation of the pressure roller pair 681 is stopped and the driving rotation is started is set within a range of 1 to 10 seconds. The crease of the sheet S is further strengthened by the forward rotation driving of the pressure roller pair 681 and the pressing at the time of stopping (see FIG. 13).
[0125]
After a predetermined time (t3 + t4) is counted, the motor M2 is driven again, and the forward rotation driving of the half-folding roller pair 671 and the pressure roller pair 681 is started. After a predetermined time t5 has elapsed by the timer, the drive rotation of the motor M2 is stopped. During the elapse of the predetermined time t5, the sheet S is discharged out of the apparatus by the forward rotation drive of the pair of folding rollers 671 and the pressure roller pair 681 (see FIG. 14).
[0126]
Note that the predetermined time t4 for temporarily stopping the paper S may be set variably in accordance with the number of the paper S. That is, the larger the number of sheets S, the longer the predetermined time t4 is variably set.
[0127]
[Folding height of half-folded paper]
FIG. 18A is a schematic diagram of an apparatus for measuring the swelling of the sheet S that has been subjected to the folding process.
[0128]
The sheet S that has been folded in half is placed on the flat plate D, and the maximum bulge height (folding height) H of the paper S is compared with the scale of the scale E that stands vertically on the flat plate D. read.
[0129]
[Table 1]

[0130]
Table 1 shows the result of actual measurement of the folding height H of the sheet S that has been subjected to the middle folding process.
The folding pressure at the clamping position X of the pair of intermediate folding rollers 671 is 30 kg. Each of the sheets S was A3 size and the weight of 64 g / m ² . The number of sheets S is 2, 5, 10, and 16. The folding height H of the sheet S is an average value of a plurality of actually measured values.
[0131]
FIG. 18B is a characteristic diagram of the folding height H of the sheet S subjected to the middle folding process. In the figure, a solid line indicates an example according to the present invention, and a broken line indicates a comparative example of the prior art.
[0132]
According to the embodiment of the present invention, the average value of the folding height H of the sheet S is 35 mm in the case of the maximum number of sheets that can be folded in half, which is 35 mm, compared with the folding height of 41 mm in the comparative example of the prior art. And good results were obtained. Even when the number of sheets S is 2, 5, or 10, the folding height H of the sheet S of the embodiment according to the present invention is smaller than that of the comparative example of the prior art, and good results are obtained. It was.
[0133]
[Second embodiment of sheet folding control]
FIG. 19 is a diagram for explaining the half-folding process of the paper S. FIG. 20 is a timing chart of a process of folding the sheet S in the middle. Hereinafter, control of the process of performing the folding process on the sheet S by the control unit 90 will be described. Differences from the first embodiment will be described.
[0134]
After the passage of the initial position HP of the folding knife 661 by the HP sensor, the folding knife 661 moves backward after a predetermined time t1. Further, after a predetermined time t2 has elapsed, that is, after the passage of the initial position HP of the folding knife 661 has been detected, the driving of the motor M2 is started after the predetermined time t6 has elapsed. With this driving start, normal rotation of the half-fold roller pair 671 and the pressure roller pair 681 is started.
[0135]
The sheet S that has been subjected to the middle folding process by the middle folding roller pair 671 that is driven and rotated by the middle folding knife 661 is nipped and conveyed by the middle folding roller pair 671 that has started driving rotation, and the leading end portion of the middle folding section of the sheet S. Are sandwiched and conveyed by a pair of pressure rollers 681 that are driven to rotate.
[0136]
When the paper discharge unit sensor PS3 detects that the leading end of the sheet S has reached the temporary stop position Z beyond the clamping position of the pressure roller pair 681, the control unit 90 stops the driving rotation of the motor M2. . Reference numeral 69 denotes an actuator that turns on and off the detection optical path of the paper discharge unit sensor PS3.
[0137]
The pressure roller pair 681 holds the stopped state until a predetermined time t7 from the timer has elapsed from the time when the driving of the motor M2 stops, and strongly presses the folded portion of the sheet S. The predetermined time t7 until the drive rotation of the pressure roller pair 681 is stopped and the drive rotation is started is set within a range of 1 to 10 seconds. The crease of the sheet S is further strongly pressed by the forward rotation driving of the pressure roller pair 681 and the pressing at the time of stopping (see FIG. 13).
[0138]
After the measurement of the predetermined time t7 is completed, the motor M2 is driven again, and the forward rotation driving of the half-fold roller pair 671 and the pressure roller pair 681 is started. After a predetermined time t8 has elapsed from the timer, the driving rotation of the motor M2 is stopped. During the elapse of the predetermined time t8, the sheet S is discharged out of the apparatus by the forward rotation drive of the pair of folding rollers 671 and the pressure roller pair 681 (see FIG. 14).
[0139]
In the embodiment of the present invention, the paper post-processing apparatus connected to the copying machine is shown. However, the present invention is also applicable to an image forming apparatus such as a printer and a facsimile, and a paper post-processing apparatus used in connection with a light printing machine. Is possible.
[0140]
【The invention's effect】
As described above, the following excellent effects can be obtained by the paper post-processing method and paper post-processing apparatus of the present invention.
[0141]
In a sheet post-processing apparatus that performs a center folding process on a sheet bundle by pressing the center portion in the conveyance direction of the sheet bundle into a clamping position between a pair of folding rollers and a pressure roller pair while pressing with a middle folding knife of a sheet ejecting unit. By holding the front end of the center folding part at a predetermined position near the holding position of the pair of pressure rollers for a certain period of time, the residual stress at the fold part of the sheet bundle disappears and the fold of the folded sheet bundle is reduced. Become. In particular, the swelling of the sheet bundle in the sheet bundle having a large number of sheets is reduced, and the finished appearance quality of the sheet bundle is improved.
[0142]
In addition, when a sheet is discharged after being subjected to a desired high-speed image forming process by an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multi-function machine, the sheet post-processing apparatus corresponds to the number of sheets. Thus, a booklet that does not bulge in the crease portion of the sheet can be quickly produced without impairing the productivity of the image forming apparatus.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an image forming system including an image forming apparatus main body, an image reading apparatus, and a sheet post-processing apparatus.
FIG. 2 is a schematic diagram illustrating a sheet conveyance path of the post-processing apparatus.
FIG. 3 is a cross-sectional view showing an upper mechanism of the post-processing apparatus.
FIG. 4 is a cross-sectional view showing a staple processing unit and a middle folding processing unit of the post-processing apparatus.
FIG. 5 is a schematic diagram illustrating a cover and sheet conveyance path, and a sheet bundle saddle stitching and center folding process;
FIG. 6 is a plan view of a sheet that has undergone saddle stitching processing, a perspective view of a sheet bundle that has undergone post-processing of saddle stitching and half-folding, and a perspective view of a sheet bundle that has been post-processed in an open state.
FIG. 7 is a cross-sectional view of a half-fold processing unit.
FIG. 8 is a perspective view of a half-fold processing unit.
FIG. 9 is a configuration diagram of a half-fold roller driving unit.
FIG. 10 is a plan view of a half-folding knife driving unit (first driving unit).
FIG. 11 is a cross-sectional view of a half-fold knife driving means (first driving means).
FIG. 12 is a cross-sectional view illustrating a state in which the leading end of the sheet passes through a half-fold forming portion.
FIG. 13 is a cross-sectional view illustrating a state in which a sheet that has been subjected to half-fold processing passes through a pressure unit.
FIG. 14 is a cross-sectional view illustrating a state in which a sheet that has been folded and pressed is discharged.
FIG. 15 is a diagram for explaining a sheet folding process;
FIG. 16 is a timing chart of a process of folding a sheet in half.
FIG. 17 is a block diagram showing the control of the post-processing apparatus.
18A and 18B are a schematic diagram of an apparatus for measuring the swelling of a sheet that has been subjected to half-folding processing, and a characteristic diagram of the folding height of the sheet that has been subjected to middle-folding processing.
FIG. 19 is a diagram illustrating a sheet folding process.
FIG. 20 is a timing chart of a process for folding a sheet.
[Explanation of symbols]
30 Binding processing unit 40 Stapling means (binding means)
60 Folding processing section 64 Second paper stacking section (stack base)
65 Folding portion movable abutting means 66 Paper ejecting means 660 Middle folding knife driving means (first driving means)
661 Middle folded plate member (middle folded knife)
67 Folding forming part 670 Middle folding roller driving means (second driving means)
671 Middle folding roller pair (first folding roller pair)
671A, 671B Middle folding roller 68 Pressure unit 681 Pressure roller pair (second folding roller pair)
681A, 681B Pressure roller 90 Control means A Image forming apparatus main body C Paper post-processing apparatus (post-processing apparatus)
H Maximum bulge height (folding height)
S Paper X Nipping position Y Maximum push-in position Z Temporary stop position a Crease

Claims (5)

The central portion in the conveyance direction of the sheet bundle conveyed on the sheet stacking unit is pressed by the intermediate folding plate member of the sheet ejecting means into the holding position of the pair of the folding rollers to form the folded portion, and then the pressure roller In a paper post-processing method of pressing and discharging the folded portion of the paper bundle by a pair,
When the leading end of the center folding portion reaches a predetermined position beyond the clamping position of the center folding roller pair, the center folding plate member is detached from the center folding portion of the sheet bundle, and the pair of center folding rollers And the pressure roller pair are driven to rotate and then stopped, and the vicinity of the front end portion of the center folding portion is held by the pressure roller pair for a predetermined time, and then the center folding roller pair and A paper post-processing method, wherein the pressure roller pair is driven and rotated to discharge the paper bundle. The central portion in the conveyance direction of the sheet bundle conveyed on the sheet stacking portion is pushed into the holding position of the pair of folding rollers while being pressed by the sheet ejecting means to form the folded portion, and then the sheet bundle is formed by the pressure roller pair. In the paper post-processing device that pressurizes and discharges the folded portion of the paper,
First driving means for driving the folding plate member of the paper ejecting means;
Second driving means for driving and rotating the pair of folding rollers and the pressure roller pair;
A tip portion position control means for stopping the tip portion of the center folding portion at a predetermined position beyond the sandwiching position of the pressure roller pair;
Drive control means for controlling the drive of the first drive means and the second drive means,
Holds the vicinity of the folded portion of the sheet bundle in the state where the pressing roller pair is clamped for a predetermined time from the time when the leading end of the center folding portion reaches a predetermined position beyond the clamping position of the pressure roller pair. After
A sheet post-processing apparatus that drives and rotates the pair of folding rollers and the pair of pressure rollers to discharge the sheet bundle. The leading end position control means is a detecting means installed at the predetermined position downstream of the pressure roller pair clamping position in the sheet conveying direction, and after detecting the leading end of the folded portion with the detecting means The sheet post-processing apparatus according to claim 2, wherein the pressure roller pair holds the folded portion for a predetermined time. The number of sheet detecting means for detecting the number of sheets in the sheet bundle is provided, and the time for which the pressure roller pair holds the sheet bundle is variably controlled according to the number of sheets in the sheet bundle. The sheet post-processing apparatus according to 2. 5. The half-folded plate member, the half-fold roller pair, the pressure roller pair, the first drive means, the second drive means, the tip position control means, and the drive control means according to any one of claims 2 to 4. An image forming apparatus comprising: a sheet post-processing apparatus having an image forming apparatus body including an image forming unit and a sheet conveying unit.

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