JP2805964B2 - Control method of paper discharge storage device and image forming apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a paper storage device used in an image forming apparatus such as a printer, and an image forming apparatus.

[Conventional technology]

In an image forming apparatus such as a printer, a sheet on which an image is recorded is discharged to a discharge storage device such as a discharge tray. There are various forms of the paper discharge storage device.
As shown in FIG. 9, a sheet P discharged from an image forming apparatus main body (not shown) is turned over by a reversing disc 3 and discharged onto an elevator tray 2 which can be moved up and down. is there. The ejected sheet P travels along an arc-shaped guide groove 3a formed in the reversing disk 3 and rotates together with the reversing disk 3 by rotating the reversing disk 3 after a predetermined time. When the leading end of the sheet P comes into contact with the stopper plate 5, the sheet P comes off the guide groove 3 a, and the elevator tray 2
Is discharged on top. At this time, the paper P is drawn to the base end 2a side of the elevator tray 2 by the rubber tongue 3b provided on the reversing disk 3, and the leading end of the paper P is aligned.

An actuator 6 for driving a sheet height detection sensor (not shown) is provided near an upper end of an elevator tray driving device 4 for moving the elevator tray 2 up and down. It is moved up and down according to the quantity. That is, when the amount of the paper P increases and the height becomes equal to or more than a certain value, the elevator tray 2 is lowered,
When the paper P is exhausted by removing the paper from the elevator tray 2, the elevator tray 2
To rise. In this specification, the height of the sheet is not the height of the sheet itself on the elevator tray 2 but the height of the sheet itself.
It means relative height from a fixed reference plane.

In this manner, the elevator tray 2 is moved up and down so that the distance between the uppermost surface of the sheets P stacked on the elevator tray 2 and the lower end of the reversing disk 3 is substantially constant. It is necessary to keep this distance substantially constant in order to stack the paper P, which has come out of the guide groove 3a with the rotation of the reversing disk 3 without being disturbed, on the elevator tray 2 while being aligned. That is what.

[Problems to be solved by the invention]

In the above-described paper discharge storage device using the elevator tray 2, for example, a large amount of sheets P of about 1800 sheets is stacked on the elevator tray 2 at a height of 250 to 270 mm. When P is removed, it cannot be removed at once, but is often removed several times. For example, if the stack of stacked sheets takes a shape as shown in FIG. 9 while the sheet P is being removed, the actuator 6 descends, and the sheet sensor determines that the sheet has run out. 4 to raise the elevator tray. However, actually, since the paper P still remains, when the elevator tray 2 moves up, the paper P is sandwiched between the reversing disk 3 and the elevator tray 2. For this reason, it becomes difficult to remove the paper P.
In addition, since the lifting force of the elevator tray driving device 4 is quite large, an excessive force is applied to the reversing disc 2, which may cause deformation and breakage.

SUMMARY OF THE INVENTION The present invention has been devised to solve the above-described problems, and controls the vertical movement timing of a vertically movable discharge tray such as an elevator tray so that an operator can move the discharge tray from the discharge tray. An object of the present invention is to make it possible to smoothly remove a sheet and not to apply excessive force to the apparatus.

[Means for solving the problem]

According to a first aspect of the present invention, there is provided a control method of a paper discharge storage device, in which a sheet discharged from a main body of an image forming apparatus is turned upside down by a reversing disk and placed on a discharge tray which can move up and down. The sheet is discharged, and the presence or absence and the height of the sheets stacked on the discharge tray are detected by a sheet sensor. When it is detected that the height of the sheet has reached a certain height or more, the sheet discharge tray is immediately moved. The paper tray is lowered, and when it is detected that there is no paper, the operation of starting the paper discharge tray to be raised is delayed.

Further, according to a second aspect of the present invention, there is provided a control method of a paper discharge storage device, wherein the paper discharged from the image forming apparatus main body is inverted by a reversing disc and discharged onto a vertically movable discharge tray. The paper sensor detects the presence and height of the paper loaded on the paper tray, and detects the state of a switch for controlling the ascending operation operated by the user, so that the height of the paper becomes equal to or higher than a certain height. When it is detected that the sheet has been ejected, the discharge tray is immediately lowered, and when it is detected that the sheet is not present, the sheet is discharged only when the lifting operation control switch does not instruct the lifting operation to be prohibited. The tray is raised.

According to a third aspect of the present invention, there is provided an image forming apparatus, comprising: a discharge unit configured to discharge a sheet on which an image is formed; and a discharge unit provided below the discharge unit and capable of stacking the sheet discharged by the discharge unit. A tray, detection means for detecting the height of the paper stacked on the paper discharge tray, and the height of the paper stacked on the paper discharge tray being higher than a predetermined height by the detection means. First control means for controlling the discharge tray to start descending when it is detected, and the height of sheets stacked on the discharge tray is determined in advance by the detection means. Control to start raising the discharge tray when it is detected that the height has become lower than the predetermined height, and when the height has become lower than a predetermined height by the detection means. Above the detection Is set to be longer than the time from when it is detected that the first control unit has detected that the height has become higher than the predetermined height to when the lowering is started. And second control means for controlling

[Action]

In the first and third aspects, when the sheet is discharged by the reversing disk (discharge means), the sheet is sequentially stacked on a discharge tray that can move up and down. As soon as the paper sensor detects that the height of the paper stacked on the paper output tray has exceeded a certain level, the paper output tray is immediately driven in the downward direction, and the inverted disc and the paper on the paper output tray Is maintained substantially constant.

When the operator removes the paper from the output tray, the paper sensor detects that the paper has run out,
The discharge tray is actually driven in the ascending direction after a certain period of time. Therefore, the paper ejection tray does not suddenly rise during the work of the operator.

Further, in the second invention, when the user prohibits the operation of raising the sheet discharge tray by the switch for controlling the operation of raising the sheet, even if the sheet sensor detects that the sheet has run out, the sheet is not discharged. The tray does not rise,
The paper on the discharge tray can be easily removed.

〔Example〕

Hereinafter, the features of the present invention will be specifically described based on embodiments with reference to the drawings.

FIG. 1 is a side view of a paper storage device to which the control method of the present invention is applied, and FIG. 2 is a schematic side view showing a main part of the paper storage device.

The paper discharge storage device 1 reverses the front and back of the paper P discharged from the image forming apparatus main body (not shown), and discharges the paper P onto an elevator tray 2 which is a vertically movable paper discharge tray. And an elevator tray driving device 4 for moving the elevator tray 2 up and down. As shown in FIG. 2, an arc-shaped guide groove 3a having an open end is formed on the periphery of the inverted disc body 3, and a rubber tongue 3b is attached to the guide groove 3a.

Paper P discharged from an image forming apparatus main body (not shown)
Enters the guide groove 3a from the opening of the guide groove 3a of the inverted disc body 3 in a stationary state, advances along the guide groove 3a, and a predetermined time after the paper P starts to enter the guide groove 3a. After the lapse of time, the reversing disk 3 makes one rotation, and the paper P starts rotating by being pulled by the rotation. However, since the stopper plate 5 is provided above the elevator tray 2 across the guide groove 3a, the leading end of the paper P collides with the stopper plate 5 and does not move any further. For this reason, the paper P escapes from the guide groove 3a and is discharged onto the elevator tray 2 in a state where the sheet P is turned upside down. At this time, the sheet P is pulled toward the base end 2a side of the elevator tray 2 by the rubber tongue 3a provided on the reversing disk 3, and the leading end of the sheet P is aligned.

At the upper end of the elevator tray driving device 3, as shown in FIG. 3, a fan-shaped light-shielding body 6a which comes into contact with the uppermost sheet of the sheets stacked directly on the elevator tray 2 or stacked on the elevator tray 2 from above, An arm 6c for supporting the light shield 6a so as to be tiltable about a shaft 6b is provided with an actuator 6 for detecting the sheet height. The actuator 6 receives a counterclockwise urging force in FIG. 3 by its own weight.

A first paper sensor 7a and a second paper sensor 7b are arranged at predetermined intervals along the tilting direction of the actuator 6. Each of the paper sensors 7a and 7b is formed of, for example, an interrupt type photo sensor, and is turned on, for example, when the light path is shielded by the light shielding body 6a of the actuator 6.

The output of each paper sensor 7a, 7b is, as shown in FIG.
The CPU 8 is supplied to a PU (Central Processing Unit) 8, based on a program written in a ROM (Read Only Memory) 9.
The elevator tray drive circuit 11 is controlled using a RAM (random access memory) 10 as a work area. The elevator tray drive circuit 11 controls the rotation, stop, and rotation direction of a drive motor (not shown) provided in the elevator tray drive 4.

Although not shown in FIG. 1, a lower limit sensor 12 for regulating a lower limit position of the elevator tray 2 is provided at a lower end portion of the elevator tray driving device 4. Supplied to

Next, the operation of the elevator tray driving device 4 and the elevator tray driving circuit 11 of the above-described paper discharge storage device will be described with reference to the flowchart of FIG.

In the initial state, as shown in FIG. 3, the elevator tray 2 is in the raised position, and there is no paper on the elevator tray 2. At this time, the light shielding plate of the actuator 6
6a is in a state of directly contacting the upper surface of the elevator tray 2, and the light shielding plate 6a is in a state of facing only the first paper sensor 7a, that is, the first paper sensor 7a is on, and the second paper sensor 7b is off. It is in the state of. Therefore, in this state, the steps in the flowchart shown in FIG.
Proceeding to 101, 102, 103, the elevator tray driving device 4 is not driven, and the elevator tray 2 is in a stopped state.

When the sheet is ejected from the image forming apparatus main body (not shown), the ejected sheet is turned to the inverted disc body 3 as described above.
Is turned upside down and discharged onto the elevator tray 2. At this time, the sheet is drawn toward the base end 2a side of the elevator tray 2 by the tongue 3b and comes into contact with the stopper plate 5, so that the light-shielding portion 6a of the actuator 6 is moved to the position shown in FIG.
As shown in FIG. 7, the paper P is sequentially pushed up and tilts clockwise. When the height of the paper P exceeds a certain level, the light shielding unit
6a faces the first and second paper sensors 7a and 7b, and both paper sensors 7a and 7b are turned on.

Therefore, the process proceeds from step 101 to step 104, and if the elevator tray 2 has not yet reached the lower limit position, the CPU 8 drives the elevator tray driving circuit 11 to lower the elevator tray 2 (step 10).
4,105). If the elevator tray 2 has already reached the lower limit position, the operation of the image forming apparatus main body is stopped without lowering the elevator tray 2 (step 10).
Along with 6), a message "Please remove the paper from the elevator tray." Is displayed on the operation panel (step 10).
7).

When the elevator tray 2 descends, as shown in FIG. 6 (b), the light-shielding portion 6a of the actuator 6 which is in contact with the uppermost surface of the paper P on the elevator tray 2 also descends, and The paper sensor 7b is turned off, and only the first paper sensor 7a is turned on.

Therefore, the process proceeds to steps 101, 102, and 103, and the elevator tray 2 stops. As a result, the lower end of the reversing disk 3 and the paper P stacked on the elevator tray 2
Is maintained at a distance suitable for discharging the paper P.

In the paper discharge storage device 1 using the above-mentioned inverted disc 3 and the elevator tray 2, some space is required on the elevator tray 2, but the lower end of the inverted disc 3 and the elevator tray 2 If the distance L (see FIG. 3) between the uppermost surface of the stacked sheets P (the upper surface of the elevator tray 2 when there is no sheet) is too large, the reversing disc 3
The posture of the paper P that has come off from the guide groove 3a changes while the paper P falls onto the elevator tray 2, and the position of the paper P is not aligned. Further, since the leading end of the sheet P is pulled toward the base end 2a side of the elevator tray 2 by the tongue 3b and brought into contact with the stopper plate 5, the leading end of the sheet P is aligned. Needs to be at a position where the tip of the tongue 3b can reach. For this reason, the distance L needs to be maintained at a relatively short constant distance of, for example, about 0.3 to 0.6 cm.

Further, when the amount of discharged paper P increases, both paper sensors 7a and 7b are turned on again, and the elevator tray 2
Is lowered, and when the second paper sensor 7b is turned off, the lowering stops. Each time the amount of the paper P increases, the above operation is repeated, and the paper P is sequentially stacked on the elevator tray 2 in a state where the distance L between the reversing disk 3 and the paper is maintained substantially constant. .

Then, when the elevator tray 2 reaches the lower limit position,
As described above, the operation of the image forming apparatus main body is stopped and a warning is displayed (steps 106 and 107).

Next, when the stacked sheets P are removed from the elevator tray 2, the elevator tray 2 is at the lower position at this time, so that the actuator 6 is moved to the lower limit regulated by the stopper 6d as shown in FIG. 6 (C). Tilt to position. Thus, the light shielding plate 6a of the actuator 6 is
Neither the paper sensor 7a nor the second paper sensor 7b is opposed, and both paper sensors 7a and 7b are turned off. Therefore, the process proceeds from step 101, 102 to step 108, and
After waiting for a time of, for example, 2 seconds, the elevator tray 2 is raised (step 109). This waiting time is set according to the time required for the user to completely remove the paper on the elevator tray 2.

The elevator tray 2 is lifted once by the two paper sensors 7a and 7b.
Is turned on (step 110). When both paper sensors 7a and 7b are turned on, the elevator tray 2 is lowered (step 111). When only the first paper sensor 7a is turned on, the lowering is performed. Stop (steps 112 and 11
3). As a result, the elevator tray 2 returns to the initial position shown in FIG.

Thus, in the present embodiment, the elevator tray 2
, The operation is delayed for a certain time. This prevents the elevator tray 2 from rising suddenly while the user is removing the paper from the elevator tray 2, and prevents the paper from being caught between the elevator tray 2 and the reversing disk 3.

The lowering operation of the elevator tray 2 is started immediately after the paper sensors 7a and 7b are turned on without any substantial delay, for example, within 10 to 40 ms. Even if the number of sheets increases, sheets can be stably stacked on the elevator tray 2.

In the above embodiment, when the elevator tray 2 is raised, the operation of the vehicle is delayed for a certain time, but the raising operation of the elevator tray 2 is prohibited for a certain time by a manual operation of the user. You may.

That is, as shown in FIG. 7, the ascending operation control switch 13 is connected to the CPU 8, and this ascending operation control switch 13 is connected to the CPU 8.
The lifting operation of the elevator tray 2 is prohibited for a certain time after the is pressed. In order to realize this processing,
The processing of step 108 in the flowchart shown in FIG.
What is necessary is just to replace the processing of the flowchart shown in FIG. That is, when it is detected that the raising operation control switch 13 is pressed (step 114), the process waits for a predetermined time (step 115), and then proceeds to step 109. The waiting time in this case is desirably set to be slightly longer than the waiting time in the control method according to the flowchart shown in FIG.

Further, every time the ascending operation control switch 13 is pressed, the prohibition and release of the ascending operation of the elevator tray 2 are switched or a toggle ascending operation control switch is used as the ascending operation control switch 13. , The lifting operation of the elevator tray 2 may be prohibited, and the lifting operation of the elevator tray 2 may be canceled when the elevator tray 2 is at the other position.

〔The invention's effect〕

As described above, in the first and third aspects of the present invention, the start of the lifting operation of the discharge tray when it is detected that there is no paper on the vertically movable discharge tray is delayed. When the operator removes paper from the paper output tray, the paper is caught between the paper output tray and the reversing disc that discharges paper to the paper output tray, making it difficult to take out the paper. The device is not damaged by excessive force.

Further, in the second aspect of the invention, the first tray is prohibited from being lifted based on a user operation.
Various inconveniences caused by the sudden rise of the paper discharge tray can be solved in the same manner as in the invention of the first aspect.

[Brief description of the drawings]

FIG. 1 is a side view of a paper discharge storage device to which the control method of the present invention is applied, FIG. 2 is a schematic side view showing a main part of the paper discharge storage device, and FIG. FIG. 4 is a block diagram showing a control circuit for controlling the operation of the paper discharge storage device, FIG. 5 is a flowchart showing the operation of the control circuit shown in FIG. 4, and FIG. Figures (a), (b),
FIG. 7C is an explanatory diagram showing the relationship between the stacked state of the sheets on the elevator tray and the attitude of the actuator for detecting the sheet height, FIG. 7 is a block diagram of a control circuit in another embodiment of the present invention, and FIG. FIG. 7 is a flowchart showing a part of the operation of the control circuit shown in FIG. 7, and FIG. 9 is a schematic side view for explaining the inconvenience of the conventional method of controlling the paper storage device. 1: Paper output storage device, 2: Elevator tray 3: Reversing disk, 3a: Guide groove 3b: Tongue 4: Elevator tray drive 5: Stopper plate, 6: Actuator 6a: Light shield, 6b: Shaft 6c: Arm, 6d: Stopper 7a, 7b: Paper sensor, 8: CPU 9: ROM, 10: RAM 11: Elevator tray drive circuit 12: Lower limit sensor 13: Lifting operation control switch

Claims (3)

(57) [Claims] A sheet reversing means for reversing a sheet ejected from a main body of the image forming apparatus by a reversing disc to discharge the sheet onto a vertically movable sheet discharge tray; The height is detected by a paper sensor, and when it is detected that the height of the paper has reached a certain height or more, the discharge tray is immediately lowered, and when the absence of the paper is detected, A method for controlling a paper discharge storage device, comprising delaying a rising start operation of a paper discharge tray. 2. The sheet ejected from the image forming apparatus main body is turned over by a reversing disc and is ejected onto a vertically movable sheet ejection tray, and the presence / absence of sheets stacked on the sheet ejection tray is determined. The height is detected by a paper sensor, and the state of a lifting operation control switch operated by a user is detected. When it is detected that the height of the paper is equal to or higher than a predetermined height, the paper is discharged. The paper discharge tray is immediately lowered, and when it is detected that the paper is not present, the paper discharge tray is raised only when the raising operation control switch does not instruct the raising operation prohibition. Control method of storage device. 3. A discharge unit for discharging a sheet on which an image has been formed, a discharge tray provided below the discharge unit and capable of stacking the sheets discharged by the discharge unit, and a vertically movable discharge tray; Detecting means for detecting the height of the paper stacked on the paper discharge tray; and detecting that the height of the paper stacked on the paper discharge tray is higher than a predetermined height by the detecting means. First control means for controlling the discharge tray to start lowering, and the height of the sheets stacked on the discharge tray is lower than a predetermined height by the detection means. Is controlled to start rising to the discharge tray when the height is detected, and the rising is detected after the detection unit detects that the height is lower than a predetermined height. Time to start The second control unit controls the lowering of the discharge tray so that the interval is longer than a time at which the lowering is started after it is detected that the height is higher than a predetermined height by the first controller. An image forming apparatus comprising: a control unit;