Patent Application
20060261543
1. Field of the Invention
The present invention relates to a sheet stacking apparatus for stacking sheets output from an image forming apparatus such as a copying machine, printer or facsimile, particularly to a sheet stacking apparatus so that all stack trays can stack the maximum number of sheets to be stacked to prevent the number of sheets to be stacked of the whole apparatus and decrease the number of temporary interrupt times of jobs and an image forming apparatus having the sheet stacking apparatus.
2. Related Background Art
A sheet processing apparatus as a sheet stacking apparatus is conventionally proposed which successively conveys sheets in which an image is recorded by an image forming apparatus into the sheet processing apparatus and selectively applies predetermined processing such as punch processing, stapling or sorting. Some of the sheet processing apparatus respectively have a plurality of sheet stack trays (stack trays) capable of performing vertical movement. The sheet stack tray is movement-controlled so that an uppermost surface of the sheets stacked on the stack tray keeps a constant position from a discharge outlet for discharging sheets. Moreover, a user sets a sheet stack tray to be used every job such as copying, FAX or printing and can switch sheet stack trays when the job is executed.
Furthermore, it is disclosed that, when sheets are stacked up to the maximum number of sheets to be stacked on a sheet stack tray, the stacking of the left sheets is prohibited and the left sheets are stacked on another sheet stack tray (refer to Japanese Patent Application Laid-Open Nos. H10-152260 and H10-305958). According to this sheet processing apparatus, it is possible to continuously discharge sheets to a switched sheet stack tray without interrupting the image forming job.
However, in the above case, for example, a sheet processing apparatus as a sheet stacking apparatus having two sheet stack trays capable of vertical movement sometimes cannot stack sheets up to the maximum number of sheets to be stacked on an upper sheet stack tray after stacking sheets up to the maximum number of sheets to be stacked on a lower sheet stack tray. This occurs in a case in which the moving range of the upper sheet stack tray to be moved so that the uppermost surface of the sheets stacked on the stack tray keeps a constant position from a sheet discharge outlet is controlled by sheets stacked on the lower sheet stack tray. In this case, the upper sheet stack tray is controlled in movement before stacking sheets up to the maximum number of stacking sheets as described above. Therefore, the number of sheets to be stacked in a sheet processing apparatus is decreased. Moreover, when movement of a sheet stack tray is controlled before one job is completed as described above, it is necessary to temporarily interrupt an image forming job until a user removes sheets from the sheet stack tray. Furthermore, as described above, when the number of sheets to be stacked is decreased, the number of times the job is interrupted increases.
An object of the present invention is to make it possible that all sheet stack trays can stack sheets up to the maximum number of sheets to be stacked, prevent the number of sheets to be stacked from decreasing in the whole sheet processing apparatus and decrease the temporary number of interrupt times.
Another object of the present invention is to be possible to stack sheets up to the maximum number of sheets to be stacked on all sheet stack trays of a sheet processing apparatus. Therefore, it is possible to prevent the number of sheets to be stacked in the whole sheet processing apparatus from decreasing. Moreover, because it is possible to decrease the number of temporary interrupt times of jobs, the sheet processing efficiency is not deteriorated.
A further object of the present invention is to provide a sheet stacking apparatus capable of stacking sheets using a plurality of sheet stack trays by switching with each other, including a plurality of sheet stack trays each of which moves to keep an uppermost surface of sheets stacked on the sheet stack tray in a constant position from a sheet discharge outlet when sheets are discharged on each of said plurality of sheet stack trays, wherein said plurality of sheet stack trays include: a first sheet stack tray, when the maximum number of sheets which are allowed to be stacked on said first sheet stack tray have been stacked thereon, which is which prevented from stacking on another sheet stack tray at least until another maximum number of sheets which are allowed to be stacked on another sheet stack tray are stacked; and a second sheet stack tray, when the maximum number of sheets which are allowed to be stacked on said second sheet stack tray have been stacked thereon, which is not prevented from stacking on another sheet stack tray at least until another maximum number of sheets which are allowed to be stacked on another sheet stack tray are stacked, wherein in a case where the number of sheets stacked on the first sheet stack tray reaches a predetermined number of sheets to be stacked which does not prevent stacking of sheets onto said another sheet stack trays until the number of sheets stacked on said another sheet stack trays reach the maximum number of sheets stacked, stacking of sheets on the first sheet stack tray is temporarily prohibited to stack sheets by switching the present sheet stack tray to a sheet stack tray other than the first sheet stack tray reaching the predetermined number of sheets.
A further object of the present invention to provide an image forming apparatus including an image forming part which forms an image on a sheet; and a sheet stacking apparatus which stacks a sheet on which an image is formed by the sheet forming part, wherein said sheet stacking apparatus capable of using a plurality of sheet stack trays by switching with each other, wherein said sheet stacking apparatus includes a plurality of sheet stack trays each of which moves to keep an uppermost surface of sheets stacked on the sheet stack tray in a constant position from a sheet discharge outlet when sheets are discharged on each of said plurality of sheet stack trays, wherein said plurality of sheet stack trays includes: a first sheet stack tray, when the maximum number of sheets which are allowed to be stacked on said first sheet stack tray have been stacked thereon, which is prevented from stacking on another sheet stack tray at least until another maximum number of sheets which are allowed to be stacked on another sheet stack tray are stacked; and a second sheet stack tray, when the maximum number of sheets which are allowed to be stacked on said second sheet stack tray have been stacked thereon, which is not prevented from stacking on another sheet stack tray at least until another maximum number of sheets which are allowed to be stacked on another sheet stack tray are stacked, wherein in a case where the number of sheets stacked on the first sheet stack tray reaches a predetermined number of sheets to be stacked which does not prevent stacking of sheets onto said another sheet stack trays until the number of sheets stacked on said another sheet stack trays reach the maximum number of sheets stacked, stacking of sheets on the first sheet stack tray is temporarily prohibited to stack sheets by switching the present sheet stack tray to a sheet stack tray other than the first sheet stack tray reaching the predetermined number of sheets.
A still further object of the present invention will become more apparent by referring to the following detailed description and accompanying drawings.
Hereafter, by referring to the accompanying drawings, preferred embodiments of the present invention are illustratively described in detail. An embodiment of an image forming apparatus having a sheet processing apparatus is described below. In this case, a copying machine is shown as an image forming apparatus and a finisher is shown as a sheet processing apparatus.
First, a schematic configuration of the whole of an image forming apparatus is described by referring to
As shown in
The document feeder 400 is mounted on the image reader 200. The document feeder 400 separates and feeds originals set on an original tray upwards one by one from the top page in the left direction of the figure in order. Then, the document feeder 400 stops the originals at a predetermined position on a platen glass 202 through a curved path. Under this state, images of the originals are read by moving a scanner unit 201 from left to right for scanning. When the scanner unit 201 performs scanning, the reading surface of an original is irradiated with the light of a lamp of the scanner unit 201 and the light reflected from the original is led to a lens through a mirror. The light passing through the lens is imaged on the image pickup surface of an image sensor 203. The optically-read image is converted into image data by the image sensor 203 and output. Predetermined processing is applied to the image data output from the image sensor 203 by an image signal control part 281 to be described later (refer to
Then, a case of forming an image on either side of a sheet is described by referring to
Sheets are selectively supplied from a cassette 111 or 112 or manual feed tray 113. These sheets are led to a conveying path and once stopped by the front end of each sheet being anti-climbed against a registration roller 114. Thereafter, the sheets are conveyed between the photosensitive drum 102 and a transfer part 104 at the timing synchronous with start of irradiation of the laser beam. The developer image formed on the photosensitive drum 102 is transferred onto a sheet supplied by the transfer part 104. Moreover, because the sheets are once stopped by the front end of each sheet being anti-climbed against the registration roller 114, a tilt of each sheet is corrected.
A sheet on which the developer image is transferred is conveyed to a fixing portion 105, which pressurizes the sheet by heat to fix the developer image on the sheet. The sheet passing through the fixing portion 105 is brought out from the printer 100 to the finisher 500 through a discharge roller 116 by a flapper 118. In this case, the sheet is brought out in a face-up state in which the image surface of the sheet is turned upwards.
To bring out the sheet in a face-down state in which the image surface is turned downwards, the sheet is brought to a sheet reverse conveying path 119 by a conveying roller 115 by the printer switching a flapper 118 when the sheet passes through the fixing portion 105. Then, by the printer switching back the sheet, the surface of the sheet is reversed and discharged from the printer 100 to the finisher 500 through the discharge roller 116.
The sheet discharged from the printer 100 is sent to the finisher 500. The finisher 500 can selectively apply stapling or sorting to bundle of sheets. In the case of this processing, it is possible to select or cancel the staple mode or sorting mode by the operation display part 600. When sorting or stapling is not set and the sheet is directly discharged, the flapper 518 is switched and the sheet is discharged to a stack tray 510 by a conveying roller 517 via a non-sorting path 516.
Then, conveying of a sheet when sorting or stapling is set to a sheet is described below by referring to
Furthermore, when the staple mode is set to the operation display part 600, sheets forming a sheet bundle to be stapled are discharged onto the intermediate processing tray 508, the sheets are arranged by the return roller 504 and matching plate 506 and then the staple operation is performed by driving a stapler 505. The stapled sheet bundle is discharged onto the stack tray 510 or 511 by the bundle discharge belt 503.
Furthermore, the stapler 505 is movable in the transverse direction (width direction) from the sheets on the intermediate processing tray 508 and perform the staple operation at optional positions of this side and recessed side. A position for applying stapling to a sheet is set by the operation display part 600.
Then, a configuration of a controller for controlling the whole of the image forming apparatus is described below by referring to
As shown in
The document feeder control part 480 drives the document feeder 400 in accordance with a designation from the CPU circuit part 150. The image reader control part 280 drives the above scanner unit 202 and image sensor 203 and transfers an analog image signal output from the image sensor 203 to the image signal control part 281.
The image signal control part 281 applies various processes after converting an analog image signal from the image sensor 203 into a digital signal, converts the digital signal into a video signal and outputs the video signal to the printer control part 180. The image signal control part 281 also applies various processes to the digital image signal input from the computer 283 through the external I/F 282, converts the digital image signal into a video signal and outputs the video signal to a printer control part 180. The processing by the image signal control part 281 is controlled by the CPU circuit part 150. The printer control part 180 drives the above exposure control part 101 in accordance with the input video signal.
The operation-display control part 680 exchanges information between the operation display part 600 and the CPU circuit part 150. The operation display part 600 has a plurality of keys for setting various functions on image formation and a display part for displaying the information showing a set state. Then, the operation display part 600 outputs a key signal corresponding to the operation of each key to the CPU circuit part 150 and displays corresponding information on the display part in accordance with a signal from the CPU circuit part 150.
The finisher control part 580 is mounted on the finisher 500 to drive the whole of the finisher by exchanging information with the CPU circuit part 150.
Then, operations of stack trays in the finisher are described below by referring to
Under the normal waiting state, the sheet stack surface of the stack tray 510 is located at the discharge outlet of a non-sort path 516 and the sheet stack surface of the stack tray 511 is located at the discharge outlet of the intermediate processing tray 508. In the case of default setting, a non-sort job is discharged to the stack tray 510 and a job for performing stapling or sorting is discharged to the stack tray 511.
It is possible to use the stack trays 510 and 511 by switching them. Switching of the stack trays includes a case of switching stack trays when reaching the maximum number of sheets to be stacked of a stack tray when discharging sheets and a case of switching stack trays by setting a job every mode.
First, switching of tack trays when sheets are stacked up to the maximum number of sheets to be stacked of a stack tray is described below by referring to
First, as shown in
In this case, when the maximum number of sheets which are allowed to be stacked on the stack tray 510 is reached while sheets forming a sheet bundle are discharged and switching of stack trays is necessary, the image forming job is interrupted after stacking of all sheets forming a sheet bundle is completed to switch stack trays. This is because when switching stack trays while discharging sheets forming a sheet bundle, a sheet bundle is stacked on two stack trays. Therefore, as described above, the image forming job is interrupted after the image forming apparatus discharges up to the final page of a sheet bundle to start switching of stack trays.
However, the number of sheets which can be stacked by exceeding the maximum number of sheets to be stacked of the stack tray 510 as a margin is limited. When it is determined that stacking of sheets by exceeding the maximum number of sheets to be stacked of the stack tray 510 is impossible, the image forming job is interrupted, removing of sheets from the tack tray 510 by informing means such as the operation display part 600 is urged to a user, it is confirmed by the sheet presence/absence detection sensor 512 that sheets on the stack tray 510 are gone out and then the image forming job is restarted.
Moreover, it is allowed to calculate the scheduled number of sheets to be stacked on the stack tray 510 every sheet bundle from job set content, compare the number of sheets to be stacked for a unit of sheet bundle with the maximum number of sheets to be stacked on the stack tray 510, interrupt the image forming job when discharge of sheet bundle one before a sheet bundle when it is determined that the maximum number of sheets to be stacked is exceeded, urge the user to remove sheets from the stack tray 510 by the informing means such as the operation display part 600, confirm by the sheet presence/absence detection sensor 512 that the sheets on the stack tray 510 are gone out and restart the image forming job.
Then, as shown in
As shown in
When the stack trays 510 and 511 respectively reach the maximum number of sheets which are allowed to be stacked on each of the trays and stacking of sheets is prohibited, the image forming job is interrupted and it is communicated by the operation display part 600 to a user to remove sheets from the stack trays. When removal of sheets from the stack trays is detected by the sheet presence/absence detection sensors 512 and 513, the image forming job is restarted. The operation after restarting the image forming job means that the operation described above by referring to
Then, a case in which stack trays are switched in accordance with setting every job mode is described. When switching stack trays in accordance with the setting every job mode, in order that an output of a copy job is discharged to the stack tray 511 and an output of a printer job or a FAX job is discharged to the stack tray 510, a user can previously perform the setting of a stack tray to which an output is discharged every job mode, by the operation display part 600. When a stack tray set every job mode is different from a stack tray at the discharge outlet in performing a job, the job stack tray is vertically moved and stack trays are switched.
Therefore, in the case of this embodiment, when stacking the maximum number of sheets to be stacked on the stack tray 511 serving as a first sheet stack tray of two stack trays and preventing the maximum number of sheets. from being stacked on the stack tray 510 serving as a second sheet stack tray, sheets are stacked by switching these two stack trays as described below. When the number of sheets to be stacked on the stack tray 511 stacking the sheets discharged from the discharge outlet of the intermediate processing tray reaches a predetermined quantity which does not prevent stacking of a maximum number of sheets to be stacked on the stack tray 510, stacking of sheets on the stack tray 511 having reached the predetermined quality is temporarily prohibited and sheets are stacked by switching the stack tray 511 to the stack tray 510.
That is, in the case of this embodiment, the stack tray 511 is switched to the stack tray 510 before sheets are stacked on the stack tray 511 until a limit in which the stack restriction on the stack tray 510 occurs to stack up to the maximum number of sheets to be stacked on the stack tray 510.
Moreover, in the case of this embodiment, even if the maximum number of sheets to be stacked is stacked on the switched stack tray 510, when the stack tray 510 does not prevent stacking of sheets up to the maximum number of sheets to be stacked on the stack tray 511 which is a sheet stack tray other than the stack tray 510, sheets are stacked as described below by switching these two stack trays. When the number of sheets to be stacked on the switched stack tray 510 reaches the maximum number of sheets, stacking of sheets on the switched stack tray 510 is prohibited and sheets are stacked by switching the stack tray 510 to the stack tray 511 which is a sheet track tray other than the stack tray 510. Thereby, the stack trays 510 and 511 can respectively stack up to the maximum number of sheets to be stacked.
Hereafter, switching of the stack trays 510 and 511 is described in detail. In this case, operations when stacking sheets up to the maximum number of sheets on each of the stack trays 510 and 511 are described for a job in which processing such as stapling or sorting is set by referring to
When a job for the processing followed by stapling or sorting is executed and sheets are discharged from the image forming apparatus to the finisher, a sheet bundle is stacked on the stack tray 511 depending on the initial state as shown in
Then, sheets are stacked on the stack tray 510 up to a predetermined number of sheets (predetermined quantity) which does not prevent stacking of sheets on the stack tray 510 up to the maximum number of sheets to be stacked (S1003). In this case, when a predetermined number of sheets is stacked on the stack tray 511, it is determined in S1004 whether sheets for forming a sheet bundle are currently discharged. That is, when sheets are stacked on the stack tray 511 up to a predetermined number of sheets and sheets for forming a sheet bundle are currently discharged, stacking of sheets is continued up to a break between stacks of sheets (S1005). However, when sheets are stacked up to the break between stacks of sheets, the image forming job is interrupted (S1006) and stacking of sheets on the stack tray 511 is temporarily prohibited (S1007).
Then, as shown in
Then, stacking is continued until the number of sheets to be stacked on the stack tray 510 reaches the maximum number of sheets (S1011). In this case, when the maximum number of sheets to be stacked is stacked on the stack tray 510, it is determined in S1012 whether sheets forming a sheet bundle are currently discharged. That is, when sheets are stacked on the stack tray 510 up to the maximum number of sheets to be stacked and sheets forming a sheet bundle are currently discharged, stacking of sheets is continued up to a break between stacks of sheets (S1013). However, when sheets are stacked up to a break between stacks of sheets, the image forming job is interrupted (S1014) to prohibit stacking of sheets on the stack tray 510 (S1015) as shown in
Then, stack prohibition to the stack tray 511 is cancelled (S1016) and the stack trays 510 and 511 are raised as shown in
Because the maximum number of sheets to be stacked is stacked on the stack tray 510 as described above, it is possible to stack up to the maximum number of sheets on the switched stack tray 511. Thereby, even when the processing such as stapling or sorting is set, it is possible to stack up to the maximum number of sheets on both the stack trays 510 and 511 as shown in
As described above, according to this embodiment, it is possible to stack up to the maximum number of sheets on all stack trays of the sheet processing apparatus. Therefore, it is possible to prevent the number of sheets to be stacked on the sheet processing apparatus from decreasing and decrease the number of temporal interruptions of a job.
In the case of the above-described embodiment, a case of two stack trays is described. However, the present invention is not restricted to this case. The same advantage can be obtained by applying the present invention to a case of three or more stack trays. For example, when there is only one stack tray among three or more stack trays for preventing up to the maximum number of sheets from being stacked on other two stack trays, it is possible to stack up to the maximum number of sheets on all stack trays of the sheet processing apparatus by applying the present invention.
In the case of the above-described embodiment, a copying machine is described as an image forming apparatus. However, the present invention is not restricted to the above case. For example, it is also possible to use another image forming apparatus such as one of a printer and facsimile system or composite system obtained by combining these functions. The same advantage can be obtained by applying the present invention to a sheet processing apparatus as a sheet stacking apparatus used for the image forming apparatus.
Moreover, in the case of the above-described embodiment, a sheet processing apparatus as a sheet stacking apparatus is described which can be set to or removed from the image forming apparatus. However, the present invention is not restricted to the above case. It is also allowed to use a sheet processing apparatus as a sheet stacking apparatus integrated with the image forming apparatus. By applying the present invention to the sheet processing apparatus, the same advantage can be obtained.
This application claims priority from Japanese Patent Application No. 2005-140708 filed on May 13, 2005, which is hereby incorporated by reference herein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-140708 (PAT. | May 2005 | JP | national |
