JP4455852B2 - Paper post-processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that stacks, sorts, and binds sheets on which images are formed and stacks them on a stack tray, and an image forming apparatus including the sheet post-processing apparatus.

2. Description of the Related Art A sheet post-processing apparatus that stacks sheets on which images are formed by an image forming apparatus such as a copying machine or a printer and performs stacking on a plurality of stack trays after performing stacking, sorting, binding and the like has been widely used. In such a sheet post-processing apparatus, conventionally, the retracted position of the lower tray after detecting the sheet surface position by turning off the sheet surface detection sensor, the downward movement of the tray to stop, making it the retracted position (e.g., (See Patent Document 1 and Patent Document 2.)
JP 2000-53308 A JP 2003-48661 A

  However, in the conventional paper post-processing apparatus as described above, a phenomenon in which the end of the paper wall surface leans against the stacking wall due to friction between the stacking wall and the end of the paper wall surface or the sensor that protrudes from the stacking wall There is a problem that the sensor flag keeps being turned on when the edge of the sheet wall surface loaded on the flag is caught, and it is lowered too much from the original sheet surface position. In this case, when the lowering operation of the tray is stopped at the original paper surface position, the vibration or reaction force at the time of stoppage acts, and the paper that has leaned or caught falls and becomes the original paper surface position.

Further, and if chattering off the paper surface detection sensor occurs, the user may, such as when placing the sheet bundle is stopped at a position too lowered more than necessary than the original paper position during the lowering operation It will be. Furthermore, when the user intentionally turns on the paper surface detection sensor, the tray is lowered by the amount that has been kept on.

Thus, in the method for stopping the downward movement by the off conventional paper surface detecting sensor, retracting operation time was longer than necessary.

  The present invention has been made paying attention to the above-described problems, and is a paper post-processing that can reliably finish the operation within a target time while ensuring the upper surface position necessary for the lower tray to be retracted. It is an object of the present invention to provide an apparatus and an image forming apparatus including the apparatus.

  The present invention solves the above problems by the following configuration.

(1) In a sheet post-processing apparatus provided with a plurality of stacking trays for stacking sheets discharged from a sheet discharge port in the vertical direction, a plurality of driving means for driving the plurality of stacking trays up or down, and the discharge A paper surface detecting means for detecting an upper surface of a stacking tray or a top surface of a sheet stacked on the stacking tray at a stacking position for stacking sheets discharged from the paper discharge port, the paper surface detecting unit being located below the paper port; The drive unit is controlled to move the stacking tray to the stacking position so that the upper surface of the stacking tray detected by the detecting unit or the upper surface of the sheets stacked on the stacking tray is below the discharge port. The height control unit and one of the plurality of stacking trays is at the stacking position, and the upper surface of the other stacking tray is detected by the paper surface detecting unit from above. When the one stacking tray moves to a retracted position below the stacking position that does not prevent the other stacking tray from moving to the stacking position, the top surface of the one stacking tray Alternatively, a retreat position detection unit that detects an upper surface of a sheet placed on the one stacking tray, and a movement distance detection that detects a movement distance of the one stacking tray driven by the driving unit to the retreat position. The movement distance detection means that the distance from the stack position already obtained to the position at which the upper surface of the one stacking tray or the upper surface of the stacked sheets is detected by the retracted position detection unit is moved. A sheet post-processing apparatus, comprising: a retract control unit that stops the one stacking tray when detected by the unit.
(2) In a sheet post-processing apparatus having a plurality of stacking trays for stacking sheets discharged from a sheet discharge port in the vertical direction, a plurality of driving means for driving the plurality of stacking trays up or down, and the discharge A paper surface detecting means for detecting an upper surface of a stacking tray or a top surface of a sheet stacked on the stacking tray at a stacking position at which a sheet discharged from the discharge port is stacked; The drive unit is controlled to move the stacking tray to the stacking position so that the upper surface of the stacking tray detected by the detecting unit or the upper surface of the sheets stacked on the stacking tray is below the discharge port. The height control unit and one of the plurality of stacking trays is at the stacking position, and the upper surface of the other stacking tray is detected by the paper surface detecting unit from above. When the one stacking tray moves to a retracted position below the stacking position that does not prevent the other stacking tray from moving to the stacking position, the top surface of the one stacking tray Alternatively, the waiting position detecting means for detecting the upper surface of the sheet placed on the one stacking tray, the time measuring means for measuring time, and the waiting position detecting means from the already obtained stacking position by the waiting position detecting means. The movement operation time calculated from the distance to the position where the upper surface of one stacking tray or the upper surface of the stacked sheets is detected and the moving speed of the one stacking tray to the retracted position has elapsed since the start of the movement. A paper post-processing apparatus, comprising: a retract control unit that stops the one stacking tray when detected by the time measuring unit.
(3) The sheet post-processing device according to (1) or (2), wherein an image forming unit that forms an image, and a plurality of stacking trays that stack sheets formed by the image forming unit in a vertical direction are provided. An image forming apparatus comprising:

(8) In the paper post-processing apparatus of (7),
When the ascending operation by the ascending control means is not completed within a preset ascending operation specified time, the ascending operation is controlled to be stopped.

(9) In the paper post-processing apparatus according to any one of (1) to (8),
Job start control means is provided for controlling the stacking tray to move to a predetermined stop position at the start of the job.

(10) In the image forming apparatus,
The sheet post-processing apparatus according to any one of (1) to (9) is provided.

According to the present invention, with the above-described configuration, the lower tray can reliably finish the operation within the target time while ensuring the upper surface position necessary for retreat .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an image forming apparatus provided with a sheet post-processing apparatus according to the present invention. Here, a schematic configuration of an electrophotographic copying machine is shown as an example.

  In FIG. 1, reference numeral 100 denotes a copying machine. The copying machine 100 includes an apparatus main body 101 and a finisher 119 which is a sheet post-processing apparatus. A document feeder 102 is provided on the upper part of the apparatus main body 101.

  The document D is placed on the document placing unit 103 by the user, and sequentially separated one by one by the feeding unit 104 and supplied to the registration roller pair 105. Subsequently, the document D is temporarily stopped by the registration roller pair 105, a loop is formed, and skew is corrected. After that, the image formed on the surface of the document is read by passing through the introduction path 106 and passing through the reading position 108. The document D that has passed the reading position 108 passes through the discharge path 107 and is discharged onto the discharge tray 109.

  When reading both the front and back sides of the document, first, the document D passes through the reading position 108 as described above, whereby the image surface of the document is read. After that, the paper passes through the discharge path 107 and is conveyed back by the reverse roller pair 110 and is sent again to the registration roller pair 105 in a state where the front and back are reversed. Then, in the same manner as when the image of one side is read, the skew of the original D is corrected by the registration roller pair 105, passes through the introduction path 106, and the image of the other side is read at the reading position 108. . Thereafter, the document D passes through the discharge path 107 and is discharged to the discharge tray 109.

  On the other hand, the document passing through the reading position 108 is irradiated with light from the illumination system 111, and the reflected light reflected from the document is guided to the optical element 113 (CCD or other element) by the mirror 112 and converted into image data. Is done. A latent image is formed on the photosensitive drum by irradiating the photosensitive drum 114 with laser light based on the image data. The latent image formed on the photosensitive drum 114 is developed with toner supplied from a toner supply device (not shown), whereby a toner image is formed on the photosensitive drum.

  In addition, paper such as paper or plastic film loaded on the cassette 115 in accordance with the toner image forming operation is sent out from the cassette 115 according to a recording signal and enters between the photosensitive drum 114 and the transfer device 116. . Then, the toner image on the photosensitive drum 114 is transferred to a sheet by the transfer unit 116, and the toner image is fixed by heating and pressurizing the sheet on which the toner image is transferred while passing through the fixing unit 117.

  When images are formed on both sides of the paper, the paper on which the image is fixed on one side by the fixing device 117 passes through the double-sided path 118 provided on the downstream side of the fixing device 117 and is again a photoconductor of the image forming unit. The toner image is transferred between the drum 114 and the transfer device 116, and the toner image is also transferred to the back surface. Then, the toner image on the back surface is fixed by the fixing device 117 and is discharged to the external finisher 119 side. Then, the toner is fixed by the fixing device 117 and is discharged to the external finisher 119 side.

  The finisher 119 sequentially takes in the sheets ejected from the apparatus main body 101, aligns a plurality of fetched sheets and bundles them into one bundle, stapling processing for binding the bundle of bundled sheets with staples, and trailing edge of the fetched sheets Each sheet process such as punching, sorting, non-sorting, and bookbinding is performed in the vicinity. As shown in FIG. 2, a folding device 400, a processing unit 500, and the like are provided.

  Here, as shown in the figure, the processing unit 500 is provided downstream of the inlet roller pair 502 for guiding the paper conveyed from the apparatus main body 101 to the inside, and the non-sorting and sorting modes for the paper. In the case of the folding mode, a sorter 552 is provided, and in the folding mode, a flapper 551 for guiding to the bookbinding pass 553 is provided.

  In the case of non-sorting, the sheet guided to the sorting path 552 by the flapper 551 is discharged onto the upper stack tray 18a and the lower stack tray 18b by the normal rotation of the pair of discharge conveyance rollers 560 that can be rotated forward and backward. A punch unit (not shown) for punching near the rear end of the sheet conveyed between the apparatus main body 101 and the finisher 119 can be attached.

  In the sort mode, the paper guided to the sort path 552 by the flapper 551 is loaded on the processing tray (intermediate tray) 630 by reverse rotation after a predetermined amount of normal rotation is performed by the discharge conveyance roller pair 560. . Note that the sheets stacked in a bundle on the processing tray 630 are subjected to alignment processing, stapling processing by the stapler 601 and the like as necessary, and then moved up and down by the paper discharge conveyance roller pair 560 (self-running). ) It is discharged onto stack trays 18a and 18b which are configured to be possible.

  On the other hand, the folding device 400 includes two pairs of staplers 818 as binding means and a folding roller pair 826 as folding means for folding a sheet bundle. Then, the sheet from the bookbinding path 553 is stored in the storage guide 820, and then conveyed until the leading edge contacts the positioning member 823 that can move in the vertical direction.

  On the storage guide side of the folding roller pair 826, a protruding member 825 that is a protrusion means is provided with the storage guide 820 interposed therebetween. The protruding member 825 provided to face the folding roller pair 826 is protruded toward the sheet bundle stored in the storage guide 820, whereby the sheet bundle is pushed out to a nip that is a folding portion of the folding roller pair 826. Then, after being folded by the pair of folding rollers 826, it is discharged to the saddle discharge tray 832.

  Here, the upper and lower stack trays 18a and 18b are attached to the finisher body 119A (see FIG. 4) so as to be movable in the vertical direction, respectively, and the stacker motor 209a as a moving means (driving means) inside the stacker motor 209a, The forward / reverse drive of 209b is transmitted to a rack portion (not shown) formed in a part of the column 37 by the pinion gear 225, so that it can be driven up and down (lifted and lowered).

In this embodiment, the upper stack tray 18a, which is the first tray, can be moved to a paper stacking position for stacking paper discharged from the paper discharge port (discharge port) 36 and a retracted position above the paper discharge port 36. And after moving to a paper stacking position, it descends as the number of stacked paper increases.

The lower stack tray 18b, which is the second tray, can move between the initial position HP and the paper stacking position. When stacking paper on the lower stack tray 18b, the upper stack tray 18a is After being moved to the retracted position, the lower stack tray 18b is moved to the paper stacking position.

The lower stack tray 18b moves to the paper stacking position and then descends as the number of stacked sheets increases. Further, when stacking sheets on the upper stack tray 18a that has been moved to the retracted position, if the upper stack tray 18a is lowered from the retracted position to the sheet stacking position, the upper stack tray 18a is lowered so as not to prevent the lowering of the upper stack tray 18a. It has become.

In the present embodiment, when the lower stack tray 18b is lowered as the upper stack tray 18a is lowered as described above, the lower stack tray 18b is retracted above the HP without being lowered to the HP. Yes.

  On the other hand, as shown in FIG. 3, the discharge port 36 for discharging sheets or stapled sheet bundles to the stack trays 18a and 18b is the top of the sheets (bundles) stacked on the stack trays 18a and 18b. When the upper surface or the sheet (bundle) is not stacked, a sheet sensor 3 for detecting the sheet stacking surface of the stack trays 18a and 18b is provided as a sheet surface detecting unit. The sheet sensor 3 can move the stack trays 18 a and 18 b to a position where the stacked sheets (bundles) do not block the discharge port 36.

  The paper sensor 3 may detect the paper (bundle) or the stack trays 18a and 18b by a mechanical flag, but the paper (bundle) or the stack tray 18a loaded with light rays such as infrared rays on the stack trays 18a and 18b. , 18b, and a light receiving unit that receives the light reflected by the sheet (bundle), and detects the position of the upper surface of the sheet on the stack tray by measuring the angle of the reflected light. It is also possible. The position detection signal detected by these detection means is input to the control unit 860 provided in the finisher main body 119A (or the apparatus main body 101).

  In this embodiment, the distance between the uppermost position of the sheets (bundles) stacked on the stack trays 18a and 18b and the paper discharge port 36 is kept constant, and the stacks are stacked on the stack trays 18a and 18b. In order to prevent the sheet (bundle) that has been placed from leaning against the slats 25, the stack trays 18a and 18b are once moved downward and then moved up to a position where the sheet sensor 3 is turned on.

In FIG. 3, reference numeral 1 denotes a first lower limit sensor as a lower limit detecting means for detecting a lower limit position of the stack trays 18 a and 18 b that gradually descends as the number of stacked sheets increases, and the paper surface detection sensor 5 is a first lower limit sensor 1. It is arranged below. Reference numeral 29 denotes a second lower limit sensor as a lower limit detecting means for detecting a lower limit position of the lower stack tray 18b.

By thus providing the sheet surface detection sensor 5 stack tray 18a, in the lower first lower limit sensor 1 for regulating the 18b lowering of, when the stacked sheets to the upper stack tray 18a, the paper stacking the sheet surface detection sensor 5 It is possible to prevent the upper stack tray 18a from colliding with the sheet on the lower stack tray 18b or the lower stack tray that is retracted at the position where the surface or the upper surface of the stacked sheets is detected (referred to as the upper retracted position).

  Reference numeral 31 denotes a sensor before the first lower limit, and reference numeral 30 denotes a sensor before the second lower limit. Both are located above the lower limit sensor. As the sheet stacking amount increases, the sheet sensor 3 keeps the sheet height constant, so that the positions of the trays 18a and 18b are gradually lowered. When the paper size loaded on the trays 18a and 18b is 216 mm or less in the transport direction, the full sheet is detected by the lower limit sensors 1 and 29, and the paper whose paper size exceeds 216 mm in the transport direction is loaded. If there is, the full sheet is detected by the sensors 31 and 30 before the lower limit.

  Next, the electrical hardware configuration of the sheet post-processing apparatus of this embodiment will be described with reference to the block diagram of FIG.

  In FIG. 5, reference numeral 900 denotes a CPU which reads out data from the stored ROM 901 and performs control and calculation while temporarily storing it in the RAM 902. Driving of each motor, solenoid, and clutch is controlled based on input information from each sensor, main body communication unit, saddle communication unit, puncher communication unit, and the like.

  Sensors for inputting signals to the CPU 900 include an entrance path sensor, a transport path sensor, an upper tray retract sensor, a lower tray lower limit sensor, a paper surface detection sensor, a lower paper surface detection sensor, an upper tray paper detection sensor, a lower tray paper detection sensor, and various HPs. (Home position) Detection sensor, staple interference sensor, upper tray lower limit sensor, upper cover sensor, front cover sensor, lower tray lower limit front sensor, and the like.

  In addition, as a driving means for outputting a control signal from the CPU 900, an inlet conveyance motor, a bundling motor, a swing motor, a front alignment motor, a back alignment motor, a rear end assist motor, an upper tray motor, a lower tray motor, a gear change There are a motor, a stapler motor, a stapler shift motor, an inlet roller separation SL, a buffer roller separation SL, a first paper discharge roller separation SL, a buffer paper presser SL, a bundle lower clutch, a shutter clutch, and the like.

  The CPU 900 controls the drive motor so that the upper surface of the tray detected by the paper sensor 3 is below the paper discharge port 36 and moves the tray to the stacking position. When the tray is moved so that the upper surface of the tray is detected by the sheet sensor 3, the tray or the sheet placed on the tray is detected at a retracted position below the stacking position that does not hinder the movement to the stacking position. And a moving distance detecting means for detecting a moving distance of the tray driven by the drive motor to the retracted position. Further, the tray is detected from the already obtained stacking position by the retracting position detecting means. Alternatively, the movement distance detecting means detects that the loaded paper or the upper surface of the sheet is moved downward to the position where it is detected. Retracting control means is configured to stop when the.

  Further, the time measuring means for measuring time is constituted by the CPU 900, and from the previously obtained stacking position until the tray or stacked paper or the upper surface thereof is detected below and detected by the retracted position detecting means. When the time measuring means detects that the moving operation time calculated from the distance and the moving speed of the tray to the retracted position has elapsed from the start of the movement, it is stopped.

  Next, the switching time prediction control of the stack tray discharge position of the finisher 119 will be described with reference to the flowcharts of FIGS. The control processing shown in these flowcharts is executed by the CPU 900 of FIG. 5 according to a program stored in the ROM 901 in advance.

  First, the job start processing operation will be described with reference to the flowchart of FIG.

  First, it is determined by the sorter start signal from the main body whether to start the job operation (S1001, S1002). If the sorter start signal is on, job operation control in steps S1003 to S1011 is performed. While the sorter start signal is ON, the reception monitoring of the pre-region request, the registration request, and the main body discharge request from the main body (S1004, S1006, S1008) and the finisher discharge completion monitoring (S1010) are performed.

  When a pre-region request is received, it means that data relating to paper such as paper size has been received from the main body, and pre-region request reception processing (S1005) is performed. The registration request means the timing when the main body finishes the registration control (S1007, details are not shown). The main body discharge request means that the paper has been discharged from the main body, and one of the paper IDs and the main body discharge signal reception counter that has been determined by the pre-region signal already received in the main body discharge request reception processing (S1009). As a result of the comparison, finisher paper conveyance control is started using paper data corresponding to a suitable paper ID (details are not shown). The finisher discharge completion monitoring is executed when a sheet is normally discharged by the paper conveyance control started after receiving the main body discharge request, and a discharge completion process (S1011) is executed.

  These are repeatedly monitored and processed while the sorter start signal is on in step S1012, and if it is detected that the sorter start signal has been turned off, it means the end of the job, so the job operation is terminated (1013).

  Next, the initial processing operation at the start of a job will be described using the flowchart of FIG.

  First, when the job start initial process is started in S1101, if a new job is started (S1102), an upper tray discharge position switching process (S1103) described later and a process tray initial process (S1104) are not shown in detail. Is executed. After the completion of each initial operation, the pre-region signal reception counter, the registration signal reception counter, the main body discharge signal reception counter, and the discharge counter are cleared in S1105, and the job start initial process is ended (S1106).

  Next, the above pre-region reception processing operation will be described using the flowchart of FIG.

  First, when a pre-region request signal indicating that the image forming apparatus connected to the finisher has newly started paper control is received (S2001), a paper data storage area is secured (S2002). Then, a pre-region reception counter is set to the paper ID which is a part of the secured area, and is set as the paper ID (S2003). Thereafter, the data about the paper received together with the pre-region request is stored in the secured area (S2004).

  Among the above data, there is paper discharge position data indicating to which stack tray the paper is to be discharged, and based on this, it is different from the paper discharge position data stored in the front paper ID area, or If there is no front sheet ID, it is determined whether the current stack tray position is different (S2005). That is, when there is no stack tray switching operation when the paper corresponding to the self paper ID is ejected, normal paper processing time calculation processing is performed in S2006.

  If a stack tray switching operation has occurred, a tray switching time calculation process is first performed in S2007 and stored as a sheet processing time (S2008). If the front paper is still being conveyed (S2009), the stack tray switching timing differs depending on the front paper operation mode. Therefore, the post-processing time is calculated based on the paper data of the front paper, and the paper processing already stored is processed. Correction is made by adding to the time (S2010).

  The paper processing time data obtained in this way is added to the pre-region response signal and transmitted to the main body (S2011). The main body that has received the paper processing time data added to the pre-region response signal discharges the paper corresponding to the transmitted pre-region signal from the main body at least the received sheet processing time from the discharge timing of the previous paper. Must do so. In this way, the pre-region request reception process is completed (S2012).

  Next, the tray switching time calculation processing operation will be described with reference to the flowchart of FIG.

  First, when the tray switching time calculation process is started (S2101), a tray stacking number prediction process is performed (S2102). Although details will be described later, the number of stacked sheets on each of the upper and lower trays immediately before the target sheet is discharged is predicted, and the number data is stored. In order to determine the tray switching direction, the tray position before switching is compared with the tray position after switching in S2103 to S2105. As a result, when it is determined that tray switching does not occur, the switching time is 0 msec (S2106).

  The switching operation from the lower tray discharge position to the upper tray discharge position is a sequence of S2107 to S2112. The time required for switching the upper and lower trays is calculated, and the longer one is stored as the tray switching time (S2110 to S2112). The calculation of the lower tray switching time is the distance from the position of the paper sensor 3 to the paper surface detection sensor 5 ÷ tray switching speed (S2107). In order to shorten the switching time, the upper tray switching time calculates the thickness of the upper tray stack from the predicted number of stacked upper trays (S2108), and calculates the upper tray operating time from the obtained upper tray operating distance. To do. Further, in the case of the upper tray, since the shutter operation time is related before and after the start, the upper tray switching time is obtained by shutter operation time × 2 + upper tray operation time (S2109).

  The switching operation from the upper tray discharge position to the lower tray discharge position is a sequence of S2113 to S2118. Also here, the time required for switching the upper and lower trays is calculated, and the longer one is stored as the tray switching time (S2116 to S2118). The calculation of the lower tray switching time is also the distance from the position of the paper sensor 3 to the paper surface detection sensor 5 / the tray switching speed (S2113). The same applies to the upper tray switching time. The thickness of the upper tray stack is calculated from the predicted number of stacked upper trays (S2114), and the upper tray operating time is calculated from the obtained upper tray operating distance. Since the same applies to the shutter operation, the upper tray switching time is obtained by (shutter operation time × 2 + upper tray operation time) (S2115). In this way, the tray switching time calculation process ends (S2119).

  Next, the above-described tray stacking number prediction calculation processing operation will be described with reference to the flowchart of FIG.

  First, when processing is started (S2201), it is determined to which tray the bundle already loaded on the processing tray is about to be discharged (S2202). If the sheet is scheduled to be discharged to the upper tray, the number already stacked on the upper tray and the number of bundles of processing trays are added and stored as the upper tray stacking scheduled number (S2203). The same applies to the case where the sheet is scheduled to be discharged to the lower tray, which is stored in the number of sheets to be stacked on the lower tray (S2204).

  Next, the paper ID is stored in order to search all trays to which the paper that is being transported in the finisher, the paper that is being transported in the main body, and the paper that is not yet fed from the main body but that is to be discharged is to be discharged ( S2205). Then, it is determined to which tray the paper corresponding to the stored paper ID is to be discharged (S2206). If the upper tray is to be discharged, 1 is added to the already stored upper tray stacking number (S2207). The same applies to the lower tray, and 1 is added to the number of scheduled lower trays (S2208). Next, when the paper ID compatible paper is the last paper being conveyed, the stacking number prediction calculation processing ends (S2209, S2211). When the paper ID compatible paper is not the final paper, the front paper of the paper ID compatible paper is used as the paper ID. Overwriting is stored (S2210).

  Next, the discharge completion processing operation will be described with reference to the flowchart of FIG.

  First, when the paper discharge completion process is started (S2301), a paper discharge signal indicating that the finisher has been discharged normally is transmitted to the main body (S2302). Thereafter, when there is a sheet next to the discharged sheet and the discharge position of the next sheet is different from the current position, a tray switching operation is performed (S2304, S2305). If the next sheet is to be discharged to the upper tray (S2305), an upper tray discharge position switching process is performed (S2307), and if the next sheet is to be discharged to the lower tray, a lower tray discharge position switching process is performed (S2306). ).

  Here, all the paper transport controls are completed. Next, the paper discharge counter is set to the paper ID (S2308), and the paper data storage area corresponding to the paper ID secured by the pre-region request is released (S2309). Finally, in step S2310, the paper discharge counter is incremented, and the paper discharge completion process ends (S2311).

  Next, the stack tray switching operation will be described.

  First, a paper discharge position switching process operation in which a sheet is discharged to the upper stack tray 18a and then moved to a position necessary for discharging the sheet to the lower stack tray 18b will be described with reference to the flowchart of FIG.

When the sheets are discharged to the upper stack tray 18a, the upper stack tray 18a has the upper surface of the stacked sheets positioned below the discharge port 36. This position is secured by stopping the raising operation after the upper surface of the stacked paper is detected by the paper sensor 3 during the raising operation of the upper stack tray 18a. Lower stack tray 18b is sensed position of the upper surface of the stacked paper sheets by the sheet surface detection sensor 5, or the upper surface of the stacked paper sheets than the sheet surface detection sensor 5 is stationary at a position located below.

  When paper is discharged from this state to the lower stack tray 18b, the upper stack tray 18a needs to be retracted above the paper discharge port 36 in order to raise the lower stack tray 18b.

  First, in order to prevent the stacked paper from flowing back to the paper discharge port 36, the shutter member (not shown) is raised to close the discharge port 36 (S2402). When the raising operation of the shutter member is finished (S2403), the upper stack tray 18a starts the raising operation (S2404), and the lower stack tray 18b is also moved upward from the position of the paper surface detection sensor 5 or the lower position. Is started (S2405).

  The upper stack tray 18a is raised to the upper limit position above the paper discharge port 36 (S2406, S2407), so that the discharge operation to the lower stack tray 18b is not affected. After the raising operation of the upper stack tray 18a, the shutter member (not shown) is lowered to open the blocked paper discharge port 36 (S2408). The raising operation of the lower stack tray 18b is performed until the upper surface of the stacked paper is detected by the paper sensor 3 (S2409, S2410).

  Thereby, the switching operation from the paper discharge position to the upper stack tray 18a to the paper discharge position to the lower stack tray 18b is completed (S2411, S2412).

  Next, a discharge position switching process operation for moving the sheet to a position necessary for discharging the sheet to the upper stack tray 18a after discharging the sheet to the lower stack tray 18b will be described with reference to the flowchart of FIG.

  As described above, the sheet discharge position to the lower stack tray 18b is a position where the upper stack tray 18a detects the upper surface of the stacked sheets by the sheet sensor 3 and the lower stack tray 18b detects the upper surface of the stacked sheets. .

  When paper is discharged from this state to the upper stack tray 18a, the lower stack tray 18b is first lowered (S2502). At the same time, before the upper stack tray 18a is lowered, a shutter member (not shown) is raised to close the paper discharge port 36 in order to prevent the stacked sheets from flowing back to the paper discharge port 36 (S2503). . When the raising operation of the shutter member is finished (S2504), the upper stack tray 18a starts the lowering operation (S2505). When the upper surface of the sheet stacked on the upper stack tray 18a is detected by the paper sensor 3 (S2506), the sheet is stopped (S2507), and the shutter discharge member 36 (not shown) is lowered to open the blocked paper discharge port 36 ( S2508).

  In addition, the lower stack tray 18b, which has already started the lowering operation simultaneously with the operation of the upper stack tray 18a, measures the stop timing regardless of the paper surface detection sensor 5. As a stop condition, when the distance from the paper sensor 3 to the paper surface detection sensor 5 is lowered (S2509), when it is lowered to the lower limit position (S2510), the paper surface detection sensor 5 is turned off at the position lowered to the sensor before the lower limit. If any one of the conditions (S2511, S2512) is satisfied.

  When both the operation of the lower stack tray 18b and the shutter operation are stopped (S2514), the elevating operation of the upper stack tray 18a is started after 100 msec (S2515) (S2516). As for the lower stack tray 18b, since the paper surface detection sensor 5 has moved a distance from the on position, the state of the paper surface detection sensor 5 at this point is normally on. In this case, it is not necessary to raise the lower stack tray 18b (S2517, S2518).

  However, if the stack of sheets stacked during the lowering operation of the lower stack tray 18b is removed, the upper surface of the lower stack tray 18b is lowered, so that the paper surface detection sensor is turned off after the stop due to the distance movement. Sometimes. In that case, the lower stack tray 18b is raised, and the lower stack tray 18b is raised until the paper surface detection sensor 5 is turned on (S2521, S2523).

  In addition, when the tray switching operation time obtained in the above-described tray switching time calculation process has elapsed from the start of the lower tray lowering operation before the paper surface detection sensor 5 is turned on, the lifting operation is stopped, The operation time is regulated (S2522). The upper stack tray 18a moves up until the paper sensor 3 is turned on (S2519, S2520). When the raising operation of both trays is completed, the switching operation from the paper discharge position to the lower stack tray 18b to the paper discharge position to the upper stack tray 18a is completed (S2520).

  In addition to the condition based on the distance count as described above, the stop condition for the descending operation can be set as a stop condition based on the time count indicating whether the descending operation time obtained from the distance and the descending operation speed has elapsed. .

  Further, the lowering amount of the lower stack tray 18b is the distance from the paper sensor 3 to the paper surface detection sensor 5. However, even when the user places a paper bundle on the lower stack tray 18b while the lower stack tray 18b is lowering, it is ensured. When priority is given to moving the upper surface position of the lower stack tray 18b or the stacked paper to a position where it does not interfere with the upper stack tray 18a, the descending amount can be set to the distance from the paper sensor 3 to the paper surface detection sensor 5 +. It is also possible to set a sheet bundle thickness that has a certain property.

In this manner, in this embodiment, the lower tray can reliably finish the operation within the target time while ensuring the upper surface position necessary for retreat .

  In the above description, the paper processing apparatus that performs the binding process as the paper processing and the image forming apparatus including the paper processing apparatus have been described as examples. However, the present invention is not limited thereto, and the invention is not limited to this. The present invention can also be applied to a device having a tray.

  The sheet post-processing apparatus of the present invention can be used in various image forming apparatuses such as electrophotographic copying machines and printers.

1 is a diagram showing a schematic configuration of an image forming apparatus according to the present invention. The figure which shows schematic structure of the paper post-processing apparatus of an Example. Explanatory drawing which shows the arrangement position of each sensor provided in the paper post-processing device Explanatory drawing showing the vertical drive of the stacking tray Block diagram showing electrical hardware configuration of paper post-processing apparatus Flowchart showing job start processing operation of the embodiment Flowchart showing job start initial processing operation of the embodiment The flowchart which shows the pre-region request reception processing operation of the example Flowchart showing tray switching time calculation processing operation of the embodiment Flowchart showing tray loading number prediction calculation processing operation of the embodiment Flowchart showing discharge completion processing operation of the embodiment Flowchart showing lower tray discharge position switching processing operation of the embodiment Flowchart showing upper tray discharge position switching processing operation of the embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st lower limit sensor 3 Paper sensor 5 Paper surface detection sensor 18a Upper stack tray 18b Lower stack tray 29 2nd lower limit sensor 36 Paper discharge port 100 Copying machine 101 Apparatus main body 119 Finisher 860 Control part 900 CPU
S paper

Claims (7)

In a sheet post-processing apparatus having a plurality of stacking trays in the vertical direction for stacking sheets discharged from a discharge port,
A plurality of drive means for each rising or falling drive the plurality of stacking trays,
A sheet surface detection means for said located below the discharge outlet, to detect the upper surface or the upper surface of sheets stacked on the stacking tray stacking tray at the loading position for stacking sheets discharged from the sheet discharge outlet,
It said stacking tray by controlling the drive means so that the upper surface of the sheet the stacked on top or the stacking tray of the stacking tray to be detected is below the sheet discharge port by the sheet surface detection means to the loading position A height control means to be moved;
When one stacking tray of the plurality of stacking trays is at the stacking position and the other stacking tray moves from above so that the upper surface is detected by the paper surface detecting means, the one stacking tray is When the sheet is placed on the upper surface of the one stacking tray or the one stacking tray when the other stacking tray is moved to a retracted position below the stacking position that does not prevent movement of the other stacking tray to the stacking position. A retreat position detecting means for detecting the upper surface ;
A moving distance detecting means for detecting a moving distance of the one stacking tray driven by the driving means to the retracted position;
By the moving distance detecting means that it has moved the distance to the position where the upper surface of the sheet being the upper surface or the load of said one tray is inspected known by the standby position detecting means from the loading position already obtained A sheet post-processing apparatus, comprising: a evacuation control unit that stops the one stacking tray when detected. In a sheet post-processing apparatus having a plurality of stacking trays in the vertical direction for stacking sheets discharged from a discharge port,
A plurality of drive means for each rising or falling drive the plurality of stacking trays,
A sheet surface detection means for said located below the discharge outlet, to detect the upper surface or the upper surface of sheets stacked on the stacking tray stacking tray at the loading position for stacking sheets discharged from the sheet discharge outlet,
It said stacking tray by controlling the drive means so that the upper surface of the sheet the stacked on top or the stacking tray of the stacking tray to be detected is below the sheet discharge port by the sheet surface detection means to the loading position A height control means to be moved;
When one stacking tray of the plurality of stacking trays is at the stacking position and the other stacking tray moves from above so that the upper surface is detected by the paper surface detecting means, the one stacking tray is When the sheet is placed on the upper surface of the one stacking tray or the one stacking tray when the other stacking tray moves to a retracted position below the stacking position that does not hinder the movement of the other stacking tray to the stacking position. A retreat position detecting means for detecting the upper surface ;
A time measuring means for measuring time;
By the standby position detecting means from the loading position already obtained to the retracted position of the distance between the one of the loading tray to a position where the upper surface of the sheet being the upper surface or the load of said one tray is tested knowledge sheet post-processing the moving operation time calculated by the moving speed of the is characterized by having a a retraction control means for stopping said one tray when detected by said time measuring means that has elapsed from the movement start apparatus. A lower limit position detecting means for detecting a lower limit position of the stacking tray;
If the lower limit position of the one tray is detected by said one tray is the lower limit position detecting means during the movement to the retracted position, characterized by controlling so as to stop the movement of said one tray The sheet post-processing apparatus according to claim 1 or 2 . It is located between the lower limit position detection means and the retracted position detection means, and has a lower limit pre-position detection means for detecting that the one stacking tray has approached the lower limit position,
When the lower limit position detecting means detects that the one stacking tray has moved to the position before the lower limit, the upper surface of the one stacking tray or the upper surface of the stacked sheets is detected by the paper surface detecting means. 4. The sheet post-processing apparatus according to claim 3 , wherein when it is detected that the position is already lower than the position detectable by the means, the movement of the one stacking tray is controlled to stop. After the movement to the retracted position is stopped, the retracted position detecting means detects that the upper surface of the one stacking tray or the upper surface of the stacked sheets is located below the position that can be detected by the retracted position detecting means. to, to have a rise control means for controlling so as to rise to the position where the upper surface or the stacked upper surface of the sheet of the single stacking tray by the driving means said one tray is detected by said standby position detecting means claims 1, wherein the sheet post-processing apparatus according to 4 or. The raising control of the one stacking tray is controlled so as to be stopped when the lifting operation of the one stacking tray by the lifting control means is not completed within a preset lifting operation regulation time. Item 6. A sheet post-processing apparatus according to Item 5 . An image forming unit for forming an image, and a sheet post-processing device according to any one of claims 1 to 6 , comprising a plurality of stacking trays for stacking sheets formed by the image forming unit in the vertical direction . An image forming apparatus.

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