JPH07115794B2 - Sheet accumulator - Google Patents

Description

The present invention relates to a sheet stacking apparatus of an image forming apparatus such as a copying machine and a laser beam printer, and more specifically, to a sheet stacking apparatus that moves in accordance with a stacking amount of sheets. The present invention relates to a sheet stacking device including a stacking unit.

(B) Conventional Technology Conventionally, a sheet stacking apparatus detects the stacking amount of sheets based on the number of stacked sheets or the thickness of stacked sheets, and when a predetermined stacking amount is exceeded, the sheet stacking apparatus determines that the sheet is in a fully loaded state and the operation unit of the image forming apparatus. Was displayed.

(C) Problems to be Solved by the Invention By the way, in recent years, high-speed image forming apparatuses compatible with various sheet sizes such as laser beam printers are becoming widespread, and accordingly, they are discharged from the image forming apparatuses. As a sheet stacking apparatus that stacks sheets, a sheet stacking apparatus that is compatible with various kinds of sheet sizes and is capable of stacking a large number of sheets is becoming popular. Therefore, when sheets of various sizes are mixedly mounted on the sheet stacking apparatus, when the sheets are stacked in order of sheet size, for example, a predetermined number of A5 size sheets are stacked, a large number of sheets such as A3 size sheets are stacked. Sheets slipped and slipped off, and stable accumulation was not possible.

(D) Means for Solving Problems The present invention is intended to solve the above problems, and collects sheets discharged from an image forming apparatus,
A sheet stacking apparatus including a stacking unit that gradually descends as the stacking progresses, and a full load detecting unit that detects that the sheets on the stacking unit are in a full load state. When sheets of different sizes are stacked on a stack of sheets, the full load amount can be changed according to the size of the sheets stacked later.

(E) Operation Based on the above-described configuration, when a large size sheet is stacked on the sheets already stacked in the stacking unit, the control unit controls the sheet size detection signal from the image forming apparatus and the stacking amount detection unit. When the stacking amount detection signal is received, the stacking amount is counted for each sheet size, and when it reaches a predetermined amount, it is determined that the stacking state is achieved.

(F) Example Hereinafter, an example according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the sheet stacking apparatus 1 is disposed behind the image forming apparatus 2, and has a discharge port 5 downstream of the discharge roller pair 3 of the image forming apparatus 2 and a carry-in of the sheet stacking apparatus 1. The mouth 6 is arranged at the same horizontal position. And
A transport roller pair 7 and a guide pair 9 are disposed downstream of the carry-in port 6, and a paper discharge unit 10 is disposed downstream of the guide pair 9. Further, the paper discharge section 10 includes paper discharge rollers 11, 12, 1
3,15 and the discharge belt 16 wound around the rollers 12,15
The paper discharge rollers 13 and 15 and the paper discharge belt 16 are rotatably supported around the paper discharge roller 12. Further, a paper surface sensor 17 is provided in the vicinity of the roller 12 so that the lever 17a is actuated by the rotation of the paper discharge belt 16 to turn on and off. On the left side of the machine body 18, a tray body 19 is supported so as to be able to move up and down, and the tray body 19 is provided with a gear 20a connected to a motor 20. On the other hand, a rack 21 is provided in the machine body 18, and the rack 21 meshes with the gear 20. Further, a paper discharge tray 22 for accumulating sheets S is arranged above the tray body 19, and further below the rack 21, a lower limit sensor for detecting the lowermost position of the paper discharge tray 22.
23 are provided.

On the other hand, the sheet stacking apparatus 1 has a control unit 25 as shown in FIG. 2, and the control unit 25 controls the entire sheet stacking apparatus 1 and calculates / processes data from each unit.
The MPU (microprocessor) 26 is provided and the MPU
26 includes ROM (read-only memory) 27 and RAM (write,
A read memory) 29 is connected by a bus line 30, and the RAM 29 is composed of a sheet size memory 31, a small size counter 32, a middle size counter 33, and a large size counter 35. And the MP
A signal from the paper surface sensor 17 and the lower limit sensor 23 is configured to be transmitted to the input / output port (not shown) of U26 via the buffers 36 and 37, respectively.
7, the MPU 26 is configured to control the drive circuit 39 of the motor 20 and the operation circuit 40 of the display unit based on the information from the lower limit sensor 23 and the RAM 29. Further, the MPU 26 is connected to the image forming apparatus 2 by a bus line 41, and is configured to obtain information such as a sheet size from the image forming apparatus 2.

Since the present embodiment is configured as described above, as shown in the flowchart of FIG. 3, the MPU 26 obtains the sheet size information from the image forming apparatus 2 and inputs the sheet size information into the sheet size memory 31, and the sheet discharge tray has already been discharged. Sheets S accumulated on 22
Remember the size of. Next, when the lower limit sensor 23 is OFF, that is, when the discharge tray 22 is not full, when the sheet S on which an image is formed by the image forming apparatus 2 is discharged from the discharge port 5, a large size (for example, A3 size) is stored in the sheet size memory 31 of the MPU 26. , B4) is stored, regardless of the size of the discharged sheet S, the sheet S is conveyed by the conveyance roller pair 7
Is conveyed to the paper discharge section 10 through the guide pair 9, and is discharged onto the paper discharge tray 22 by the paper discharge section 10. Similarly,
When a large number of sheets S are accumulated on the discharge tray 22 and the discharge belt 16 is pushed up, the lever 17a blocks the light emitting portion and the light receiving portion (both not shown) of the paper surface sensor 17, and the sensor 17 is OF.
It is in the F state and it is detected that the sheets S accumulated on the discharge tray 22 have a predetermined height. Then, the signal from the paper surface sensor 17 is transmitted to the MPU 26 via the buffer 36,
26 commands the motor 20 to rotate to the lower side in order to lower the discharge tray 22. Then, the motor 20 rotates to lower the discharge tray 22 by a predetermined distance, and the next sheet S can be stacked on the tray 22. Similarly, output tray
When the lower limit sensor 23 is turned on as the 22 descends in sequence, the sensor
The signal of 23 is transmitted to the MPU 26 via the buffer 37,
26 determines that the sheet is in the full state and displays the full state on the display section 38 by the operating circuit 40, stops the sheet stacking apparatus 1, and further notifies the image forming apparatus 2 of the full state via the bus line 41.

In addition, the medium size sheet S is stored in the sheet size memory 31.
When (for example, A4, B5) is stored, that is, when the middle-sized sheets are already stacked on the discharge tray 22,
When the medium size sheet S or the small size sheet S (for example, A5, B6) is discharged from the image forming apparatus 2, the discharge tray is used until the lower limit sensor 23 is turned on, similarly to the above.
The middle size sheets S or the small size sheets S are stacked on the sheet 22. On the other hand, when the large size sheet S is discharged from the image forming apparatus 2, the MPU 26 increments the large size counter 35 of the RAM 29, and when the counter 35 counts 100 large size sheets S, the MPU 26 determines that the MPU 26 is in a full state. The operating circuit 40 displays a full load on the display unit 38, stops the sheet stacking apparatus 1, and further notifies the image forming apparatus 2 of the full load state through the bus line 41.

Further, when the small size sheets are discharged from the image forming apparatus 2 when the small size is stored in the sheet size memory 31, the small size sheets S are accumulated on the discharge tray 22 until the lower limit sensor 23 is turned on. On the other hand, when the large size sheet S is discharged from the image forming apparatus 2, the MPU 26 increments the large size counter 35 of the RAM 29, and when the counter 35 counts 50 large size sheets S, the MPU 26 determines that it is full. The operating circuit 40 displays a full load on the display unit 38, stops the sheet stacking apparatus 1, and further notifies the image forming apparatus 2 of the full load state through the bus line 41. Further, when the middle-sized sheet S is discharged from the image forming apparatus 2, the MPU 26 adds the middle-sized counter 33 of the RAM 29, and when the counter 33 counts 100 middle-sized sheets S, the MPU 26 judges that the MPU 26 is in a full state. Operating circuit 40
Thus, the display unit 38 displays a full load, the sheet stacking apparatus 1 is stopped, and the image forming apparatus 2 is informed of the full load state through the bus line 41.

In addition, in the above-mentioned embodiment, the sheet size is set to three types of large, middle and small, but the present invention is not limited to this, and the sheet size may be set to various types.

In the above-described embodiment, when different size sheets S are mixedly mounted, the different size sheets S are counted from the first sheet, but the stacking state is affected while a large number of sheets of a predetermined size are stacked. When a very small number of different size sheets S are accumulated, the different size sheets S may not be counted.

(G) Effect of the Invention As described above, according to the present invention, when the control unit stacks a larger size sheet on the sheets already stacked in the stacking unit, the load amount is changed according to the sheet size. Since it is configured, stable stacking can be performed even when sheets of various sizes are mixed.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a sheet stacking apparatus according to the present invention, FIG. 2 is a block diagram showing the configuration of a control unit, and FIG. 3 is a flow chart showing the operation of the present invention. DESCRIPTION OF SYMBOLS 1 ... Sheet stacking device, 2 ... Image forming device, 22 ... Stacking unit, 17,23 ... Stacked amount detecting means, 25 ... Control unit, S ...
… Sheet.

Claims (1)

[Claims] 1. A stacking unit that stacks sheets discharged from an image forming apparatus and gradually descends as the stacking progresses, and a full load detecting unit that detects that the sheets on the stacking unit are in a full load state. In the sheet stacking apparatus provided with the stacking amount switching means, when the sheets of different sizes are stacked on the previously stacked sheet bundle, the stacking amount can be changed according to the sheet size to be stacked later. Characteristic sheet stacking device.