JP3931524B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus including a stacker device that stacks and stores printed sheets on one tray, and more particularly to control when different sized sheets are mixed and discharged onto a tray.
[0002]
[Prior art]
Some image forming apparatuses such as printers, copiers, and digital multi-function peripherals have a large-capacity stacker device. The stacker device includes a tray that can move up and down with a large stroke, and stacks and holds printed sheets discharged from the image forming apparatus main body on the tray in the discharge order. The tray is driven up and down in accordance with the sheet stacking amount, and the height difference from the sheet discharge port to the top surface of the sheet on the tray is controlled to be substantially constant.
[0003]
There are a wide variety of paper sizes handled by the image forming apparatus, and papers of different sizes are often stacked on the stacker device. However, if such size mixed loading is allowed unconditionally, the sheet bundle on the tray may collapse. For example, when a large sized sheet is discharged after a large amount of small sized sheets are discharged onto a tray, a portion that protrudes from the previously loaded small sized sheet may slip and cause a load collapse.
[0004]
As a technique for preventing such load collapse, there is a technique disclosed in Japanese Patent Laid-Open No. 7-206256. In this technique, the collapse of the load is prevented by prohibiting discharge of a sheet larger than the size of the sheet at the top of the tray onto the tray.
[0005]
[Problems to be solved by the invention]
The prior art described above has a problem that a job using a sheet larger than the already loaded sheets cannot be executed, and the job execution limit is too strong. For example, when someone has nothing on the tray and prints about 10 sheets of B5 paper, discharges them to the stacker device and leaves them, then someone else puts A3 paper on the stacker device. Even if it is going to be put out, the use of the stacker device is prohibited. In this case, it is necessary to remove the B5 paper from the tray even though there is no concern about the collapse of the load (since it is about 10 sheets), which is troublesome for the user. For the user, it is necessary to remove the print results of others, and it often feels troublesome.
[0006]
SUMMARY An advantage of some aspects of the invention is that it provides an apparatus capable of preventing the collapse of a sheet while relaxing the restriction on execution of jobs having different sheet sizes.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus having a stacker device capable of stacking sheets of different sizes on a tray, the height of the sheets stacked on the tray. If a mixed limit detecting means, which is pre-Symbol mixed limit detecting means has detected the mixed-size limit height exceeds the paper size that can be stacked stably tray but for detecting that exceeds the size mixed limit height and a control means you allow to discharge onto.
[0008]
Here, the “size” of the paper includes not only the size of the paper but also the concept of the orientation of the paper. Also, the “height” of the paper represents the amount of paper in the stacking direction, and is not only expressed in units of normal “height” such as cm, but also “the number of sheets” stacked. It may be expressed as In this configuration, the process of determining whether or not to permit discharge onto the tray according to the paper size is limited to the case where the paper stacking height on the tray is equal to or higher than the mixed loading height. Therefore, if the height is less than the mixed loading limit, it can be discharged onto the tray regardless of the paper size, and flexibility is improved.
[0009]
In the reference example , the image forming apparatus includes a reference size storage unit that stores a reference size, a stacking condition storage unit that stores a stackable condition that defines a sheet size that can be stacked on the reference size sheet, Means for updating the reference size of the reference size storage means according to the size of the paper detected by the size detection means each time the paper is discharged onto the tray; and the size detection means for the paper to be discharged onto the tray. And a determination unit that determines whether or not the sheet satisfies the stackable condition, and the control unit satisfies the stackable condition in the determination unit. If it is determined, a job for discharging the paper onto the tray is permitted, and if not, the job is prohibited.
[0010]
According to this reference example , after exceeding the mixed loading limit height, it is possible to prevent the collapse of the load while flexibly receiving the job.
[0011]
In yet another reference example , the size mixed limit height is determined according to the stackable condition.
[0012]
In this way, by determining the limit height according to the loadable conditions that are controlled according to the mixed loading limit height, free loading up to the limit corresponding to the conditions can be performed.
[0013]
In another reference example , the reference size storage means sets the reference size of the reference size storage means to the maximum sheet size that can be loaded on the tray when the mixed limit detection means does not detect an excess of the size mixed limit height. A means for setting is further provided.
[0014]
In this reference example , the reference size is the maximum paper size immediately after the mixed loading limit detection unit detects the mixed loading limit height. Accordingly, any size of paper can be accepted at that time, and the size of paper that can be discharged after exceeding the mixed loading limit height is not unnecessarily limited.
[0015]
In another reference example , the reference size storage means is configured using a nonvolatile memory.
[0016]
In this reference example, even when the paper on the tray when returning from power-off or the like, since the reference size as a reference for stabilizing cargo determination at that time remains in the nonvolatile memory, determination using the same Processing can continue. Therefore, it is not necessary to remove the sheet from the tray when the power supply is restored from the shutdown or the like.
[0017]
The apparatus of another reference example includes a limit excess detection means for detecting whether or not the height of the paper loaded on the tray exceeds a predetermined limit height, and the paper on the tray. Means for determining whether or not discharge is permitted, and when the limit excess detection means does not detect the limit height exceeding, the means is more gradual than when the means detects the limit height excess. Means for performing the determination under various determination conditions.
[0018]
According to this reference example , until the sheet stacking height on the tray exceeds the limit height, the limit on the sheet that can be discharged is loose, so that the sheet is accumulated up to the limit height while preventing the collapse of the load. In the meantime, the frequency with which the sheet needs to be removed from the tray is reduced.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. Hereinafter, an image forming apparatus provided with a post-processing apparatus having a stapling function and a large-capacity stack function will be described as an example.
[0020]
In the above-described prior art, in the control for preventing the stack tray from collapsing, the rule of “prohibiting discharge of paper larger than the size of the topmost paper” is applied from the state where there is no paper on the stack tray. On the other hand, in this embodiment, in the load collapse prevention control, it is necessary to remove paper from the stack tray by allowing free size mixing until the paper stacking amount on the tray reaches a predetermined limit height. Reduce the frequency of
[0021]
In the load collapse prevention control according to the present embodiment, after the sheet stacking height exceeds the limit height, the sheet size that can be stacked is limited. Various methods can be considered to limit the size when the limit height is exceeded. For example, a method that allows discharge of only the smallest size paper, a method that allows discharge of only a frequently used paper size (for example, A4 portrait), or a size that can be stably stacked on the topmost paper on the tray There are methods that allow only the discharge of paper. Here, the size that can be stably stacked on the uppermost sheet is, for example, a sheet size within a range where the protrusion from the uppermost sheet does not induce sliding (here, “size” is the size of the sheet) As well as orientation elements). When using the last method, the correspondence between the top paper size and the size that can be stably stacked on the table is tabulated, and the table is referred to when the paper is discharged to the stack tray. What is necessary is just to judge whether discharge is possible.
[0022]
Note that the maximum height at which size loading is freely allowed varies depending on what paper size restriction method is adopted after the height is exceeded. That is, after the free loading up to the limit height, the limit height is determined so that no load collapse will occur even if the sheets are stacked according to the adopted paper size restriction method.
[0023]
For example, in a method in which only discharge of a minimum size sheet is allowed after the limit height is exceeded, the limit height can be made higher than the other methods exemplified. This is because the minimum size paper hardly protrudes from any of the underlying papers, and even if the paper is additionally stacked, the degree of increase in the possibility of load collapse is small. Even if the paper is stacked to a certain extent in the free mixed state (as a result, the possibility of collapse of the load slightly increases), the collapse of the load is unlikely to occur as long as it is the smallest size of paper that can be loaded thereon.
[0024]
In the method that allows only frequently used paper after the limit height is exceeded, or the method that allows only the paper size that can be stably stacked relative to the size of the topmost paper, the limit height is a method that allows only the minimum size. Compared to lower.
[0025]
In addition, the limit height which permits size free mixing is calculated | required beforehand by experiment etc., and an apparatus is comprised based on this.
[0026]
As described above, by allowing size mixing freely at a predetermined limit height, it is possible to greatly reduce the situation in which it is necessary to remove sheets from the stack tray.
[0027]
Hereinafter, an example of the apparatus configuration and processing procedure of this embodiment will be described. Hereinafter, a case will be described in which a highly flexible discharge size restriction method based on the top paper size is adopted as the paper size restriction method after the limit height is exceeded. However, the scope of application of the present invention is not limited to adopting this method. Further, the method of limiting the discharge size after the limit height is exceeded is not limited to the illustrated one.
[0028]
First, a configuration example of the post-processing device 10 will be described with reference to FIG. The post-processing device 10 receives printed paper from an IOT (image output terminal: also called print engine) side that forms an image on the paper, and conveys the paper along the paper path 12 to the compiler tray 14. . A stapler 16 is provided in the vicinity of the compiler tray 14. When stapling is performed, the compiler tray 14 is moved to the stapler 16 and the stapler 16 is operated. The discharge roll 18 presses and grips the sheet bundle on the compiler tray 14 from above and below to rotate, and discharges the sheet bundle from the sheet discharge port 20 onto the stack tray 22. The stack tray 22 is moved up and down by driving the motor.
[0029]
An upper surface sensor 24 is provided in the vicinity of the upper limit of the raising / lowering range of the stack tray 22. The upper surface sensor 24 detects the height of the upper surface of the sheet on the tray 22, and when the height exceeds a predetermined level, the stack tray 22 is lowered by a certain amount by driving the motor. By such control, the stack tray 22 automatically descends as the sheets are accumulated, and the height difference between the top surface of the sheet on the tray 22 and the sheet discharge port 20 is kept almost constant, so that the sheet is stabilized. Discharged / accumulated. A lower limit sensor 28 is provided at the lower limit of the raising / lowering range of the stack tray 22. When the lower limit sensor 28 detects the tray 22, the control unit of the post-processing device 10 notifies the image forming apparatus main body that the stacking limit has been reached.
[0030]
Further, on the upper surface side of the stack tray 22, a paper presence sensor 30 for detecting the presence or absence of paper on the tray 22 is provided. When the sheet is removed from the tray 22, the sheet presence sensor 30 detects the absence of sheet. Then, the tray 22 is returned to the uppermost position.
[0031]
Further, the post-processing apparatus 10 of the present embodiment is provided with a mixed loading limit sensor 26 in order to detect that the sheet stacking height on the stack tray 22 has reached a limit height that allows free mixed loading. . The mixed loading limit sensor 26 is provided at a position lower than the upper limit of the tray 22 by a limit height that allows the above-described size mixed loading freely (which is obtained in advance through experiments or the like). It is detected that the tray 22 has been lowered to the position or less when it is blocked by a sheet bundle or the like above.
[0032]
The post-processing device 10 is connected to an image forming apparatus main body provided with an IOT (print engine), and executes the control for preventing the above-described collapse of goods while communicating with a control unit of the image forming apparatus main body.
[0033]
Next, a control mechanism for the post-processing apparatus 10 and the image forming apparatus main body 50 for such control will be described with reference to FIG.
[0034]
Outputs of various sensors (upper surface sensor 24, mixed loading limit sensor 26, lower limit sensor 28, sheet presence / absence sensor 30, etc.) provided in post-processing apparatus 10 are input to control unit 100. The control unit 100 controls the sheet conveyance in the sheet path 12, the operation of the compiler tray 14, the stapler 16 and the discharge roll 18, the raising and lowering operation of the stack tray 22 in accordance with the detection results of these various sensors. Exchange of necessary instructions and responses with the image forming apparatus main body 50 is performed. FIG. 2 illustrates only functions related to load collapse prevention control among the various control functions of the control unit 100.
[0035]
The stacking determination unit 106 is a mechanism that determines whether a sheet to be discharged can be stacked on the tray 22 without collapsing based on a discharge size restriction method based on the topmost sheet size. The stack determination unit 106 compares the sheet size acquired from the image forming apparatus main body 50 by the size acquisition unit 108 with the reference size stored in the reference size memory 110 (that is, the size of the uppermost sheet on the tray), and discharges the sheet. It is determined whether or not the size of the paper sheet to be satisfied satisfies a condition for stacking with respect to the reference size. This condition is stored in the stacking condition storage unit 120, for example, in the form of a table or the like representing the correspondence between the reference size and the size that can be stably stacked on the paper of this size. When the paper to be discharged does not satisfy the stackable condition, the control unit 100 prohibits the discharge of the paper because there is a possibility of the collapse of the load.
[0036]
The determination control unit 102 controls the determination operation of the stack determination unit 106. In other words, the detection signal of the mixed loading limit sensor 26 is input to the determination control unit 102, and the operation of the stacking determination unit 106 is stopped while the tray 22 is not detected by the mixed loading limit sensor 26. During this time, the paper height on the tray 22 has not reached the limit height of the free size mixed loading, and therefore it is not necessary to determine whether or not the paper can be stacked by the stack determination unit 106. During this time, the determination control unit 102 permits a paper discharge request of any size from the image forming apparatus main body 50. On the other hand, when the mixed loading limit sensor 26 detects the tray 22 (or a sheet thereon), the determination control unit 102 causes the stack determination unit 106 to perform the above determination. Then, when the determination result is “stackable”, discharge of the sheet requested by the image forming apparatus main body 50 is permitted, and when it is “unstackable”, it is prohibited. The determination of permission or prohibition is notified from the response notification unit 104 to the image forming apparatus main body 50.
[0037]
A control unit 500 that controls each mechanism of the image forming apparatus main body 50 includes a job control unit 510 that controls execution of a job such as printing and copying, and a paper size detection unit 520 that detects the size of a sheet used for the job. I have. The paper size can be obtained from, for example, job instruction contents input from the operation panel. The paper size detected by the paper size detection unit 520 is notified to the size acquisition unit 108 on the post-processing apparatus 10 side at the start of a job or the like. The job control unit 510 receives, from the response notification unit 104, a determination as to whether or not the post-processing apparatus 10 has made a discharge in response to this notification, and performs job execution or stop control according to the determination result.
[0038]
FIG. 3 shows a processing procedure on the image forming apparatus main body 50 side when a job using the post-processing apparatus 10 is started. In this procedure, the main body 10 first notifies the post-processing device 10 of the paper size of the job designated by the user (S10), and waits for a notification of the determination result from the post-processing device 10 (S12). When the determination result is received, the main body 10 determines whether the determination result is “discharge permitted” or “discharge prohibited” (S14), and if it is “permitted”, the job is started (S16). If the determination result of the post-processing apparatus 10 is “prohibited”, the execution of the job is prohibited, and the user is requested to remove the sheets on the stack tray 22 of the post-processing apparatus 10 (S18). Here, for example, a message such as “There is a risk of paper collapse. Please remove the paper in the stack tray and press the start button again” is displayed on the operation panel of the main body 50. Then, if the user removes the sheet in response to this message and presses the start button again, the processing procedure of FIG. 3 is executed again from the beginning, and this time the job is executed because the discharge of the post-processing device 10 is permitted. Is done.
[0039]
The processing procedure on the post-processing apparatus 10 side at this time is shown in FIG. When the post-processing device 10 obtains the paper size of the job from the main body 50 (S20), it checks the output of the mixed loading limit sensor 26 (S22). When the mixed loading limit sensor 26 is OFF (that is, the tray 22 is not lowered to the position of the sensor), any paper size is accepted, and the post-processing device 10 notifies the main body 50 of ejection permission ( S30).
[0040]
On the other hand, when the output of the mixed loading limit sensor 26 is ON (the tray 22 is lowered below one of the sensors) in S22, the post-processing device 10 stores the paper size of the job and the reference size memory 110. It is determined whether or not the relationship with the reference size (that is, the size of the topmost sheet) satisfies the condition set in the stacking condition storage unit 120 (S24, S26). As a result of the determination, if it is determined that the stacking condition is satisfied, that is, it is determined that “stacking is possible”, the paper size value of the job is overwritten in the reference size memory 110, and the reference size is updated (S28). If the paper size of the current job is equal to the reference size, this update operation can be omitted. Then, the post-processing device 10 notifies the main body 50 of discharge permission (S30).
[0041]
If it is determined in S26 that the stacking is impossible, the post-processing device 10 sends a notification of paper discharge prohibition to the main body 50 (S32). In response to this, the main body 50 prompts the user to remove the paper. When the paper is removed and the start of the job is instructed again, the procedure of FIG. 4 is repeated.
[0042]
In the above procedure, the reference size stored in the reference size memory 110 is reset to the maximum sheet size that can be stacked on the stack tray 22 when the mixed loading limit sensor 26 is turned off. The reference size does not change while the mixed loading limit sensor 26 is OFF. By resetting in this way, sheets of all sizes can be accepted immediately after the mixed loading limit sensor 26 is turned on for the first time. While the mixed loading limit sensor 26 is ON, the value of the reference size is sequentially updated to the discharged paper size.
[0043]
By the above processing procedure, when the paper stacking height is at a predetermined mixed loading limit height, it is possible to allow the user to freely load different sizes of paper onto the stack tray, thereby causing the user to feel troublesome such as paper removal. Can be avoided. Then, after the limit height is exceeded, the size of the sheets to be stacked can be limited to reduce the risk of collapse.
[0044]
The procedure described above is merely an example, and various modifications can be made within the scope of the present invention. For example, in the above procedure, before starting the job, it is determined whether or not the paper of the job can be discharged without collapsing, and it is determined whether or not the start of the job is permitted. In response to the start instruction, it is possible to determine whether or not the job can be discharged after starting the job. If the job cannot be discharged, the job can be interrupted.
[0045]
In this case, as shown in FIG. 5, the image forming apparatus main body 50 immediately starts job processing (printing or the like) in response to the user pressing the start button, and the post-processing apparatus 10 has the paper size of the job. (S40). Receiving this notification, the post-processing device 10 executes a determination process similar to that shown in FIG. However, in this procedure, it is not necessary to notify the main body 50 of the discharge permission from the post-processing apparatus 10 (since the job has already been started), S30 is unnecessary. The post-processing device 10 notifies the main body 50 (that is, notification of prohibition of ejection) only when it is determined that loading is impossible. If the main body 50 does not receive the prohibition notification (No in S42), the main body 50 continues the job processing. On the other hand, when the prohibition notification is received, the main body 50 interrupts the execution of the current job and displays a message requesting removal of the sheets on the stack tray 22 on the operation panel or the like (S44). Then, it waits for the notification that the paper on the tray 22 has been removed from the post-processing device 10 (S46), and when the notification is received, cancels the interruption of the current job and restarts the job ( S48).
[0046]
In this procedure, even in the case of a paper size job that does not satisfy the stackable conditions, one or several sheets may be discharged onto the stack tray 22, but at this level, it is unlikely that serious load collapse will occur. The point is unlikely to be a substantial problem. Rather, this procedure is more advantageous than the above embodiment in view of the fact that the time from when the user gives an instruction to start a job (for example, pressing the start button) until the first print result is discharged becomes shorter. It can be said that.
[0047]
Further, in the apparatus configuration of the above embodiment, if the reference size memory 110 is a non-volatile memory (for example, NVRAM), the reference size information remains in the memory 110 even when the power is shut off or the system is restored from the residual heat mode. Therefore, it is not always necessary to remove the paper on the tray 22 when returning. That is, conventionally, when returning from a power shutdown or the like, information on the uppermost paper size (reference size) on the tray 22 is lost. For safety reasons, if there is paper on the tray 22, it is removed. Until then, the job to be ejected to the tray was not permitted, but if the reference size is stored in the non-volatile memory, the job is a paper size that can be loaded with respect to the reference size. This can be done without removing the paper.
[0048]
In the above embodiment, the post-processing apparatus 10 determines whether or not the job sheets can be stacked without collapsing, but this determination may be performed on the image forming apparatus main body 50 side. It is. In this case, the determination control unit 102, the stack determination unit 106, the reference size memory 110, and the stack condition storage unit 120 are provided on the main body 50 side, and the detection signal of the mixed loading limit sensor 26 is acquired from the post-processing device 10 at the start of the job. The determination can be made.
[0049]
It should be noted that such a mechanism for preventing collapse of the load can be provided on either the main body 50 side or the post-processing apparatus 10 side, but this mechanism is only meaningful when the post-processing apparatus 10 is provided. Therefore, it is not wasteful in terms of system configuration to be provided on the post-processing apparatus 10 side.
[0050]
Further, in the above example, whether or not the paper stack amount has reached the size mixed limit height is determined based on whether or not the stack tray 22 is detected by the mixed load limit sensor 26. Instead, image formation is performed. It is also possible to count the number of sheets discharged to the tray 22 by the apparatus main body 50 or the post-processing apparatus 10 and determine whether this count value has reached a certain number.
[0051]
In the above example, the size mixed limit height is a fixed value, but the limit height can be varied according to the size of the paper discharged onto the tray 22. In this case, the image forming apparatus main body 50 or the post-processing apparatus 10 indicates what size paper is discharged to the tray 22 (that is, what size paper group is currently assumed to be on the tray 22). Monitor and determine the limit height of mixed loading according to the monitoring result. For example, the mixed loading limit is determined such that the discharged paper is mainly 300 sheets for B4, 200 sheets for A4, and the like. Further, depending on the minimum size of the discharged paper, for example, if the minimum size is B5, the mixed limit height is 150 sheets, and if the minimum size is A4, the combined limit height is 200 sheets. Means for determining the mixed loading limit height from the history of the discharged paper size is provided in the image forming apparatus main body 50 or the post-processing apparatus 10. In this example, whether or not the sheet stacking amount on the tray has reached the mixed loading limit height can be determined by the count value of the number of discharged sheets.
[0052]
In the above description, the post-processing apparatus having a stapler has been described as an example. However, the present invention can be applied to a post-processing apparatus having a post-processing function and a stack function other than a stapler, or a simple stack apparatus having no stapler. Needless to say, it is applicable.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a post-processing apparatus according to an embodiment.
FIG. 2 is a diagram illustrating a configuration of a control mechanism of the image forming apparatus according to the embodiment.
FIG. 3 is a flowchart illustrating a processing procedure of the image forming apparatus main body.
FIG. 4 is a flowchart showing a processing procedure of the post-processing apparatus.
FIG. 5 is a flowchart illustrating a modification of the processing procedure of the image processing apparatus main body.
[Explanation of symbols]
10 post-processing device, 12 paper path, 14 compiler tray, 16 stapler, 18 discharge roll, 20 paper discharge port, 22 stack tray, 24 upper surface sensor, 26 mixed load limit sensor, 28 lower limit sensor, 30 paper presence sensor.

Claims (2)

An image forming apparatus including a stacker device that can stack sheets of different sizes on a tray,
Mixed loading limit detecting means for detecting whether or not the height of the paper loaded on the tray exceeds the size mixed limit height ;
If the previous SL mixed limit detecting means has detected the excess mixed-size limit height, and control means allow to discharge the sheet size that can be stacked stably onto the tray,
An image forming apparatus comprising: The control means refers to a table in which a correspondence relationship between a top sheet size on the tray and a size that can be stably stacked with respect to the top sheet size is tabulated. Item 2. The image forming apparatus according to Item 1.

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