JPH0676173B2 - 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 amount of collected sheets based on the number of collected sheets or the thickness of accumulated sheets, and when a predetermined number of collected sheets is exceeded, the sheet stacking apparatus determines that the sheet is fully loaded. It was displayed on the operation panel.

(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.
As a sheet stacking apparatus that stacks sheets discharged from sheets (abbreviated as “P”), a sheet stacking apparatus that supports a large number of sheet sizes and is capable of stacking a large number of sheets is becoming popular. Therefore, the sheet stacking apparatus needs a strength capable of withstanding the full weight of the maximum size sheets and a means for assisting the alignment when the minimum size sheets are fully loaded. However, the sheets frequently used by many general users are sheets in a specific size range, and in order to accumulate a large number of sheets in the specific size range, the maximum size or the minimum size of sheets ensures the same number of stacking capacity. In order to achieve this, the strength must be increased or a means for preventing the collapse of the sheet must be provided, which results in an increase in cost, and if the desired accumulation capacity of the maximum size or minimum size sheet is adjusted without increasing the cost, There is a problem that the sheet accumulating ability is reduced.

(D) Means for Solving the Problem The present invention is intended to solve the above-mentioned problems, and at least two load amount detecting means are provided in the stacking unit, or the stacking means is provided. It is characterized in that the number of stacked sheets is counted, and based on a sheet size detection signal from the image forming apparatus, the stacking position detection means is switched to change the full-sheet position of the sheets. is there.

(E) Operation Based on the above configuration, when stacking large-sized or small-sized sheets, the first stacking amount detection means detects the full-sized positions of the large-sized and small-sized sheets and stacks the middle-sized sheets. At this time, the second stacking amount detecting means, which has a larger stacking amount than the first stacking amount detecting means, detects the full load position of the middle-sized sheets.

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

As shown in FIG. 4, the sheet stacking apparatus 1 is arranged behind an LBP (laser beam printer) 2 and the LB
The discharge port 5 of the P2 sheet conveying unit 3 and the sheet stacking apparatus 1
It is arranged at the same horizontal position as the carry-in port 7 of the sheet conveying section 6.

As shown in detail in FIG. 1, the sheet stacking apparatus 1 has a sheet conveying section 6 inside the machine body 8 and the conveying section 6
Is a conveyance roller pair 4 (see FIG. 4), conveyance rollers 9a, 9b, 1
0, 11, conveying guides 12, 13, discharge rollers 15, 16 and discharge belts 17 are wound around discharge rollers 19 and 20, and rollers 18 are attached to the rollers 19 and 20. . Further, a sensor 21 is arranged in the upper portion inside the machine body 8, and the sensor 21 is arranged from the transport rollers 10 and 11 to the discharge roller 1.
It is configured to detect the presence or absence of the sheet S on the conveyance paths up to 6,20. Further, on the rear side of the body body 8, a pillar
22 are erected, and rail plates 2 are provided on both side surfaces of the column 22.
3,23 is fixed. The rail plates 23, 23 are provided with rollers 24, 24, 27, 27 provided on one side of the tray drive unit 25.
Is guided and supported so as to be movable in the vertical direction, and a DC motor 26 is arranged in the tray drive section 25. Further, a gear 27 is fixed to the shaft 26a of the motor 26, and a pinion 29 is arranged close to the gear 27. Furthermore,
The pinion 29 meshes with the gear 27 via an idle gear 30, and meshes with a rack 31 provided on the column 22 to move the tray drive unit 25 in the vertical direction by driving the motor 26. Is configured. A tray 32 for accumulating the sheets S is provided above the tray drive unit 25, and a sensor 33 for detecting the presence or absence of the sheets S is arranged on the tray 32. Further, a sensor 35 for detecting the height of the sheets S when the stacking height of the sheets S accumulated on the tray 32 reaches a predetermined height and pushes up the discharge roller 19 is provided in the machine body 8. , The sensor
Reference numeral 35 includes a light emitting portion, a light receiving portion (both not shown), and a lever 18 that moves integrally with the discharge roller 19.

On the other hand, as shown in FIG. 2, the tray drive unit 25 is provided with micro switches 36 and 37 for detecting the lowered position of the tray 32, and thus for detecting the sheet stacking amount on the tray, The microswitches 36, 37 each have an L-shape in a side view, and are provided with levers 39, 40 whose corners are rotatably supported by shafts 39a. Rings 39b and 40b are formed on one side of the levers 39 and 40, and the rings 39b and 40b and the hook 25b projecting inside the case 25a of the tray drive unit 25 are respectively provided with springs. 41,4
1 is stretched. Further, one ends A, A of the levers 39, 40 are biased upward by the springs 41, 41 to push up the lever portions 36a, 37a of the microswitches 36, 37. Further, ribs 42, 43 are provided so as to project in parallel and stepwise in the vertical direction of the column 22, and one end B, B of the levers 39, 40 is brought into contact with the ribs 42, 43 to rotate the ribs 42, 43 so that other Edge A
Is separated from the levers 36a, 37a of the microswitches 36, 37 so that the switches 36, 37 are turned off.

On the other hand, the sheet stacking device 1 and the LBP 2 have control units 45 and 46 as shown in FIG. 3, and the control unit 45 controls the entire device 1 and calculates / processes data from each unit. MP to
A U (microprocessor) 47 is provided and the MPU
In addition, a ROM (read-only memory) 49, a RAM (write / read memory) 50, and an input / output port 51 are provided, which are connected by a bus line to a drive motor 53 of the transport unit 6.
It is configured to control the drive circuits 55 and 56 of the DC motor 26. Further, the input / output port 51 has sensors 21, 33,
The signals from the 35 and the microswitches 36 and 37 are configured to be transmitted via the respective buffer memories 57, 59, 60, 61 and 62, and are connected by the control unit 46 of the LBP2 and the bus line 63. There is.

Next, the operation of this embodiment will be described. Large size sheet S (eg A3, B
4) and the small size sheets S (for example, A5 and B6) are discharged from the discharge port 5 by the sheet conveying unit 3 and are carried in from the carry-in port 7 of the sheet stacking apparatus 1, and the sheet size is detected by the sheet size detecting means (not shown). It is transmitted to the control unit 45 of the stacking device 1. Then, the sheet S is nipped and conveyed between the conveyance guides 12 and 13 to the discharge rollers 16 and 20 by the conveyance roller pair 4 and the conveyance rollers 9a, 9b, 10 and 11. At this time, the sheet S is detected by the sensor 21, and the signal of the sensor 21 passes through the buffer memory 57, the input / output port 51, and the MPU.
Be transmitted to. In addition, the sheet S is formed by the discharge rollers 15, 16, 19, 2
The sheet is discharged onto the tray 32 by 0. Similarly, when a large number of sheets S are accumulated on the tray 32 and the discharge roller 19 is pushed up, the lever 18 blocks the light emitting portion and the light receiving portion of the sensor 35, and the sensor 35 is turned off, so that the sensor 35 is turned on. It is detected that the sheet S has a predetermined height. And the sensor
A signal from 35 is transmitted to the MPU 47, and the MPU 47 commands the DC motor 26 to rotate downward so as to lower the tray drive unit 25. In this way, the tray drive unit 25 descends by a predetermined distance, and the sheets S can be stacked. In this way, when the tray drive unit 25 is sequentially lowered and one end B of the lever 39 contacts the rib 42, the other end B of the lever 39 is separated from the lever 36a of the micro switch 36 and the switch 36 is turned off. It becomes a state. Further, the signal of the switch 36 is transmitted to the MPU 47 via the buffer memory 61, and the MPU 47 judges that it is in the full state based on the signal and notifies the control unit 46 of the LBP2 through the bus line 63. Then, the control unit 46 displays on the operation unit (not shown) of the LBP 2 that the stacking of the sheets on the sheet stacking apparatus 1 is full. Next, the operator confirms the display of the full state, and the sheet S on the tray 32 is
When is removed, the sensor 33 detects that the sheet S is not on the tray 32. Then, when the signal from the sensor 33 is transmitted to the MPU 47 via the buffer memory 59, the MPU
Based on the signal, the DC motor 26 is commanded to rotate to the rising side. As a result, when the tray drive unit 25 rises and the tray 32 pushes up the discharge roller 19, the lever 18 detects the sensor.
The light emitting part and the light receiving part of 35 are blocked, and the sensor 35 is turned off. Further, the signal of the sensor 35 is transmitted to the MPU 47 via the buffer memory 60, and the MPU 47 receives the DC motor based on the signal.
26 is stopped and the tray 32 is made to stand by for stacking the sheets S.

On the other hand, the sheet size is a middle size sheet S (for example, A
4, B5), when the sheets S are successively stacked on the tray 32 and the tray drive unit 25 descends in sequence, the lever 39 contacts the rib 42 and the micro switch 36 is turned off, the micro switch 36 is turned off. Signal of the MPU4 via the buffer memory 61
7, but the MPU 47 does not issue any command. Then, when the sheets S are accumulated on the tray 32, the tray drive unit 25 descends sequentially, the lever 40 contacts the rib 43, and the micro switch 37 is turned off.
Signal is transmitted to the MPU47 through the buffer memory 63,
Based on the signal, the MPU 47 judges that it is fully loaded and
It notifies to the control unit 46 of 2 through the bus line 63. Next, the control unit 46 displays on the operation unit of the LBP 2 that the sheet stacking in the sheet stacking apparatus 1 is full.

In this embodiment, the micro switches 36 and 37 for detecting the tray position are used as the sheet stacking amount detecting means of the tray 32, but a slide volume interlocking with the tray 32 may be used as the detecting means.

Further, in the present embodiment, the sheet accumulation amount is detected by detecting the position of the tray 32, but the number of sheets accumulated may be counted for each sheet size, and the full state may be determined based on this count value. In this way, it is possible to determine the full state based on the sheet size mixed loading ratio even when different sheet sizes are loaded together.

(G) Effect of the Invention As described above, according to the present invention, since the full load position is changed according to the sheet size, the ability to collect sheets in a specific size range used by a large number of users is ensured and the maximum size is increased. And the ability to collect sheets of the smallest size can be tailored to the desired capacity.

Further, the stacking means is guided up and down along the side surface of the apparatus main body, and the motor means for driving the stacking means up and down integrally moves up and down together with the stacking means to drive the pinion. The configuration can be simplified and compacted.

Further, since the rotating body that discharges the sheet to the stacking unit is configured to be movable up and down and also serves as the position detecting unit that detects the upper surface of the sheet or the stacking unit, the structure is simplified and the stacking amount of the sheet or By accurately detecting the upper end position of the stacking means, it is possible to perform accurate lifting control of the stacking means.

Further, since the exclusive presence / absence detection unit for detecting the presence / absence of the sheet on the stacking unit is included, it is possible to accurately detect that the sheet is completely removed from the stacking unit. It is possible to reliably prevent a malfunction such as driving the motor means by collapsing or removing only a part of the sheet, thereby improving reliability.

When the stacking amount of the sheets stacked on the stacking unit is detected by the counting unit that counts the number of sheets, in combination with the information from the sheet size information unit, the stacking position of the stacking unit is set to a large number of sheets. The size can be set appropriately and finely according to the size, and the mounting amount detecting means composed of a plurality of switches or the like is not required, and an extremely simple configuration is sufficient.

In particular, when sheets of different sheet sizes are mixedly loaded on the stacking means, the number of sheets for each sheet size is counted,
The full loading state of the stacking unit can be determined at an appropriate position based on the mixed loading ratio of each sheet size.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a sheet stacking device according to the present invention,
FIG. 2 is a view showing the load amount detecting means, (a) is a plan view, (b) is a side view, and (c) is a perspective view. FIG. 3 is a block diagram showing a control unit of the sheet stacking apparatus, and FIG. 4 is a side view schematically showing a connection state between the image forming apparatus and the sheet stacking apparatus. 1 ... Sheet stacking device, 2 ... Image forming device, 17, 18, 19
...... Rotating body (discharge belt, discharge roller), 26 …… Motor means (DC motor), 29 …… Pinion, 31 …… Rack, 32
........ Stacking means (tray), 33 ... Presence / absence detecting means (sensor), 36, 37 ... Loading amount detecting means (micro switch), 45, 46 ... Control means (control section), S ... Sheet.

Claims (3)

[Claims] 1. A stacking unit that stacks sheets discharged one by one from an image forming apparatus and that can be moved up and down by being guided along a side surface of the apparatus main body, and presence / absence detection for detecting the presence / absence of sheets on the stacking unit. A sheet size for detecting the uppermost position of the stacking unit or the stacking amount of the sheets, and the lowermost position of the stacking unit. A plurality of load amount detecting means arranged at different positions corresponding to the above, and a drive source having a pinion capable of moving up and down together with the stacking means and meshing with a rack for moving up and down,
When the presence / absence detecting means detects the absence of a sheet, the sheet is normally rotated and the stacking means is raised until the position detecting means detects it. A motor unit for lowering the amount of paper, a sheet size information unit for notifying the size of the sheet discharged from the image forming apparatus, and one of the plurality of stacking amount detection units according to the size information from the sheet size information unit. A sheet laminating apparatus comprising: a control unit that selects and activates the sheet. 2. A stacking unit capable of moving up and down for stacking sheets discharged from an image forming apparatus, a stacking amount detecting unit for detecting a stacking amount of sheets on the stacking unit, and a stacking amount from the stacking amount detecting unit. In a sheet stacking device, which comprises means for lowering the stacking means by a fixed amount according to information, counting means for counting the number of sheets stacked in the stacking means is provided as the stacking amount detecting means. Further, a sheet size information means for notifying the size of the sheet discharged from the image forming apparatus is provided, and the number of full sheets is judged for each sheet size according to the size information from the sheet size information means. A sheet stacking device characterized by the above. 3. The sheet stacking apparatus according to claim 2, wherein when different kinds of sheet sizes are mixed, the number of sheets is counted for each sheet size, and the full load position is determined based on the sheet size mixed loading ratio.