JPS6341354A - Sheet loading device - Google Patents

Abstract

PURPOSE:To always secure the superior arrangement of the loaded paper sheets independently of the loading quantity by varying the driving time of a lowering means for lowering a loading means according to the counted value of a counting means for the loaded paper sheets. CONSTITUTION:After the arrival at an outlet roller, an output paper sheets is transported further, and discharged and loaded onto a tray 19 or the loaded paper sheets on the tray 19. When the paper sheeets are loaded continuously, the loaded paper sheet surface rises, and a paper discharging roller 14 is lifed up gradually, and when the roller 14 is lifted up to a prescribed position, a controller detects this state by the input supplied from a paper surface sensor 18, and an elevating and lowering motor 23 is driven to lower the tray 19. The motor driving time is selectively determined by the counted value in a counting device, namely the number of sheets of the loaded paper sheets 20 on a tray 21. In other words, as the number of loaded paper sheets increases, the time for lowering the motor is reduced by a prescribed time, and the tray lowering quantity in the case ranging from the small quantity loading to the large quantity loading can be kept constant, and can be kept in the range in which the superior loading arrangement can be secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a device for stacking sheets (hereinafter referred to as paper) discharged from a sheet processing device such as a printer or a copying machine.

[Prior art]

2. Description of the Related Art Conventionally, as a device for stacking paper ejected from a printer, a copying machine, etc., a device having a stacking tray that can be raised and lowered is known.

FIG. 7 schematically shows a conventional configuration of a stacking tray of a paper stacking device having a stacking tray that can be raised and lowered. 2 is a paper discharge roller, 2 is a paper discharge port, 3 is a stacking tray, and 4 is a stacked paper stacked on the stacking tray 3.

In FIG. 7, when the hard copy output sheets are sequentially conveyed by the sheet discharge roller 1 and outputted from the sheet discharge port 2, the output sheets are stacked on the primary stacking tray 5, which becomes the stacked paper 4. Here, when the number of stacked papers 4 increases and the paper surface approaches the paper discharge port 2 by a predetermined amount, a tray lift motor (not shown) is driven for a certain period of time to lower the stacked tray. Further, the timing of this tray descent is given by a stacked paper surface sensor (not shown) that detects when the stacked paper surface has risen to a certain position.

If the output is continued further, the tray lifting motor is driven for a certain period of time so that the tray is lowered every time the paper surface rises to a specified position. That is, during continuous loading, the loading tray 5 is intermittently lowered. FIG. 8 shows a conventional control flowchart for lowering the stacking tray during the loading process.

By the way, to ensure the alignment of the stacked papers in the stacking tray,
The angle of incidence when the paper ejected from the paper ejection port 2 contacts the stack tray 5 or the stack 4 already loaded is always within a certain range depending on the shape of the stack tray 5, etc. is desirable. In other words, it is desired that the distance between the paper discharge port 2 and the paper surface of the stacked paper 4 is always within a certain range.

In general, many paper stacking devices having elevating trays carry out large-volume stacking, and the weight of the stacked papers stacked on the stacking tray is thought to vary over a wide range. In other words, the load applied to the loading tray lifting motor also varies over a wide range. Therefore, in the control that detects only the paper surface and drives the motor for a certain period of time as described above, the speed of the motor or the rise time in the case of a constant speed control motor changes depending on the load, so the paper surface of the paper ejection port 2 and the paper stack 4 There was a problem in that the distance between the stacked sheets was no longer within a range that guaranteed alignment of the stacked sheets.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet stacking device that eliminates the problems of the conventional example described above and can always guarantee good alignment of stacked sheets regardless of the stacking amount.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 6 show embodiments of the present invention.

FIG. 1 shows a main cross section of the stacking section of the paper stacking device according to the present invention.6. 7. 8. 9 is a conveyance roller that conveys the paper in the stacking device; 10. 11 is a conveyance guide that defines a paper conveyance path; 12. 13. 14. Reference numeral 15 denotes a group of paper ejection rollers that eject the conveyed paper to a stacking tray, which will be described later. 16 indicates a paper ejection belt that is wrapped around the paper ejection rollers 14 and 15. Reference numeral 17 indicates conveyance from the transport rollers 9 and 8 to the paper ejection rollers 13 and 15. This is a sensor (photointerrupter) that detects the presence or absence of paper on the path, and is hereinafter referred to as a paper discharge sensor. Reference numeral 18 denotes a sensor (photointerrupter) that detects the paper surface of the stacked paper, which will be described later, based on the position of the paper discharge roller 14, and is hereinafter referred to as a paper surface sensor. Reference numeral 19 denotes a tray on which the paper discharged from the paper discharge roller is stacked; 20, the stacked paper stacked on the tray 19; and 21, a sensor for detecting the presence or absence of paper on the tray 20, hereinafter referred to as a tray paper presence/absence sensor. Reference numeral 22 denotes a tray drive unit that controls lifting and lowering of the tray 19, 23 a DC motor that provides driving force for lifting and lowering the tray, and 2
4, 25, and 26 are a group of gears that convert the rotational force of the DC motor 23 into a force for lifting and lowering the tray.

FIG. 2 shows the configuration of FIG. 1 in an electrical block diagram. 27 is a paper stacking device according to the present invention, 30 is a control device for the paper stacking device 27, and 31 is a paper conveying force in the paper stacking device 27 (conveying roller group 6, 7, 8, 9, paper ejection roller group 1
2. 13. 14. 15); 32 is a microcomputer in the control device 30; 33 is a ROM in which program information for operating the microcomputer 32 is stored; 34 is a ROM in the microcomputer 32; "RAM" that stores or provides information according to specifications, 35
36 is an input/output device that takes in each input information in the paper stacking device to the microcomputer 32 and outputs signals to each output device according to instructions from the microcomputer; This is a counting circuit that counts the number of sheets of paper.

In the configurations shown in FIGS. 1 and 2 above, when output paper is inserted into this stacking device from a hard copy output device such as a printer, the output paper is conveyed along the conveyance path between the id 11 and the conveyance roller 7. .6 toward the conveyance rollers 9, 8, and from the conveyance rollers 9, 8 further to the exit roller group 12.
13. 14. 15. At this time, the paper discharge sensor 17 is turned on when there is paper at that position, and turned off when there is no paper.

That is, when a plurality of output sheets are conveyed, the sheet discharge sensor 17 repeats 0N10FF each time. That is, by counting the number of times the paper ejection sensor turns from OFF to ON, the number of output sheets that have been conveyed (later to be stacked) can be determined. The counting circuit 36 performs this counting.

The counting circuit has a function of adding 1 to the count value each time the paper ejection sensor is turned from OFF to ON, and a function of setting the count value to zero by inputting a clear signal, which will be described later. Further, count value information of the counting circuit is input to the microcomputer 32 via the input/output circuit 35, and a clear signal for the count value is sent from the microcomputer 32 to the input/output circuit 3.
5 to the counting circuit. When the microcomputer 32 determines that there is no stacked paper 20 on the tray 19 based on the input information from the paper presence/absence sensor 21, it generates a count clear signal.

As described above, the microcomputer 32 can know the number of sheets 20 stacked on the tray 21 at any given time. Fourth
The figure shows a flowchart of the above counting operation.

Next, the output paper that has reached the exit roller is further conveyed,
The paper is discharged onto the tray 19 or onto the stack of paper already stacked on the tray 19 and stacked. As the sheets are further stacked continuously, the surface of the stacked sheets rises, and accordingly, the paper discharge roller 14 is gradually lifted up. When the paper discharge roller 14 is lifted up to a predetermined position, the control device 36 detects this based on the input from the paper surface sensor 18, and drives the tray lift motor 23 to lower the tray 19. (Gear 24
(When the tray is rotated CCW, the tray is lowered.) The motor drive time at this time is selectively determined by the count value by the counting device, that is, the number of @sheets 20 loaded on the tray 21 at that time.

In general, as the number of trays loaded increases, so does the mass, so the load on the motor decreases due to the influence of gravity when lowering the tray. Therefore, with a DC motor (without constant rotation control), the rotation speed will be high, and the amount of tray descent per unit time will be large. If the time for lowering the motor is shortened by a predetermined time as the number of sheets loaded increases, the amount of tray descent when the tray is lowered can be kept constant from when a small amount is loaded to when the tray is fully loaded. The positional relationship between the stacked paper surface and the stacked paper surface can be maintained within a range that can guarantee good product S alignment.

Figure 5 shows the motor drive time when the tray is lowered when the number of sheets loaded on the tray (N) is N≦NA (state 1), NA<N<NB.
(state 2), NB≦N (state 3) (however, NA<Ns)
The three-stage TF ([s] (state 1
) TM[Sl (for state 2), TL(Sl
12 is a flowchart of an embodiment of tray lowering control that is changed to (in the case of state 3). (The positional relationship between the paper ejection port and the stacked paper surface in order to obtain good stacking alignment has a certain range, so the tray lowering time can be changed depending on the case within that range.) Fig. 6 is an example of a system using a paper stacking device according to the present invention. 42 is a paper stacking device according to the present invention, and 34 is a laser beam printer that provides hard copy output paper to the paper stacking device 42.

〔effect〕

As explained above, by providing a means for counting the number of loaded sheets and changing the driving time of the lowering means that lowers the loading means according to the counted value, good alignment that is not affected by the amount of sheets loaded can be achieved. A sheet stacking device having the above structure can be realized.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the loading section of the paper stacking device according to the present invention, FIG. 2 is a block diagram of the embodiment shown in FIG. 1, and FIG. 3 is a schematic diagram showing the torque-rotation speed characteristic of the DC motor. , FIG. 4 is a flowchart of the stacked paper counting operation of the embodiment,
FIG. 5 is a flowchart showing the tray lowering control of the embodiment, FIG. 6 is a diagram showing an example of the system configuration of the embodiment, FIG. 7 is a schematic diagram showing the conventional example, and FIG. 8 is the tray lowering control of the conventional example. FIG. 18...Paper surface sensor, 19...Tray, 21...
Paper presence/absence sensor, 23...DC motor, 36...Counting circuit.

Claims (1)

[Scope of Claims] A loading means for loading sheets conveyed from a sheet processing section; a lowering means for lowering the loading means; a counting means for counting the number of sheets loaded on the loading means; a control means for lowering the loading means by intermittently driving the means, the control means comprising:
A sheet loading device characterized in that the driving time of the lowering means is changed according to a count value by the counting means.