JPH03232633A - Mult1-stage paper feed device - Google Patents

Abstract

PURPOSE:To prevent occurrence of jamming by setting the sheet conveying speed of a conveying means downstream of a common conveying passage to a value which is always higher than the sheet conveying speed of a conveying means upstream thereof so that a sheet is conveyed preferentially of pulling of the sheet. CONSTITUTION:When the leading end of an image-transfer sheet is pinched between intermediate rollers 12a, 12b in a paper feed unit 3B, the image-transfer sheet is pulled by the intermediate rollers 12a, 12b at a higher speed. At this time, a part of the sheet pinched between intermediate rollers 12a, 12b on the trailing end side is rotated by the action of a gear 20a incorporated with a one-way clutch at a conveying speed of the image-transfer sheet, and is conveyed in a rotating condition in which the sheet is fed preferentially of pulling of the image-transfer sheet. Thereby, the image-transfer sheet if fed, without causing any slack, to the direction of the paper feed unit 3A in the conveying passage 10. Similarly, the image-transfer sheet is conveyed on a conveying path 10A in the paper feed unit 3A, thereby the image-transfer sheet is fed to a copying machine body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multistage paper feeding device that transports paper by stacking a plurality of paper feeding units to form a common transport path.

[Conventional technology]

For example, in an image forming apparatus such as a copying machine, it is necessary to reproduce a formed image on paper. For this reason, a conveyance path is formed to convey paper, or transfer paper in the case of a copying machine, to the area where the image is formed, and transfer paper of various sizes is supplied according to the requirements of the copying machine, and the image is transferred. will be implemented.

An example of this is a multistage paper feeding device disclosed in Japanese Patent Laid-Open No. 136442/1983. This multi-stage paper feeder is different from a paper feeder equipped with multiple paper feed trays for storing copy paper.
The copy paper is drawn out from the paper feed port of the paper feed tray selected in response to an instruction from the copying machine, and is conveyed to the bottom of the image form of the copying machine via a common conveyance path. In other words, the multi-stage paper feeding device according to this conventional example includes a copy paper transport means that can change the transport speed, and a detection device that is provided at a predetermined position on the copy paper transport path and detects the passing of the leading and trailing edges of the copy paper. and a signal detected by the detection means, measures the time until the leading edge of the copy paper conveyed first arrives, and compares this with a reference value. The copying machine is equipped with a control means for changing the conveyance speed for a predetermined period of time, so that copying paper is fed into the paper feed port of the main body of the copying machine at regular intervals.

In this conventional example, paper feed trays arranged in multiple stages are used, and copy sheets are conveyed through a paper feed port of the main body of the copying machine at regular intervals via a common conveyance path. When copy paper is transported using a common transport path in this way, the copy paper that has been separated and fed from the paper feed tray is transported via a transport path that is previously provided on the paper feed device side. If configured, the conveyance speed on the conveyance path can be easily adjusted by using one drive source.

However, when a paper feed tray such as the conventional paper feed tray is used, there is a limit to the types of copy paper that can be stacked. Therefore,
A paper feed tray as a storage means for copy paper, a separating/feeding device that separates the copy paper in the paper feed tray and feeds the paper to the transport path, a 4ti feed roller, and a drive motor that drives the transport roller. Paper feeding devices have been developed in which conveying devices including the above are stacked as one unit, that is, a sheet feeding unit, according to the needs of the user, and the conveying path of each sheet feeding unit is used as a common conveying path to convey copy sheets.

[Problem to be solved by the invention]

By the way, when a common conveyance path is used in this way, if the conveyance speed of copy sheets on the common conveyance path varies, jams may occur within the conveyance path. In particular, if the conveyance speed of the upstream conveyance roller is higher than the conveyance speed of the downstream conveyance roller of the conveyance path, a jam occurs between the re-conveyance rollers.

In other words, when copy paper is transported using a common transport path, as in the conventional example described above, the copy paper that has been separated and fed from the paper feed tray is transported through a transport path that is provided in advance on the paper feed device side. If it is configured to transport, the transport speed on the transport path can be easily adjusted by using a single drive source. However, if each paper feeding unit is independent including its drive source, the load may vary depending on the paper feeding unit.
Variations in the drive source including the drive motor, variation in the drive power source, etc. occur. Therefore, when copy sheets are conveyed through a common conveyance path constituted by each paper feed unit, conveyance control that takes into account the variations is required. In this way, in order to take into account the manufacturing and operational variations of each part of each paper feeding unit and to perform control that reduces the variation error of each paper feeding unit, it is necessary to use, for example, servo control, synchronous motor drive, etc. It is necessary to introduce high-precision rotation speed control technology.

However, it is undeniable that the cost will increase if the above-mentioned high-precision rotation speed control technology is introduced.

The present invention has been made in view of the actual state of the prior art, and its purpose is to provide a low-cost multistage paper feeding device that is free from the risk of jamming. ] The above object includes a storage container for storing paper, a separating and feeding means for sequentially separating and feeding paper sheets one by one from the storage container;
A plurality of paper feed units each having a conveyance means for conveying the paper separated and fed by the separation paper feed means via a conveyance path are stacked, and a common conveyance path is formed by the conveyance path of each of the paper feed units. At the same time, the conveyance means of each paper feeding unit forms a relay conveyance means, and furthermore, the paper conveyance speed of the conveyance means on the downstream side in the conveyance direction of the common conveyance path is always set to be higher than the paper conveyance speed of the conveyance means on the upstream side in the conveyance direction. This is achieved by a multistage paper feeding device configured to separate paper from the storage container of an arbitrarily selected paper feeding unit and feed the paper through a common conveyance path.

To control the speed of the conveyance means of the multi-stage paper feeder, the conveyance means are driven by DC motors, and the voltage applied to these DC motors is set so that the conveyance speed on the downstream side of the common conveyance path is higher than the conveyance speed on the upstream side. This is done by introducing an applied voltage control circuit that performs drive control.

[Operation] According to the above means, since the paper transport speed on the downstream side in the transport direction is always higher than the paper transport speed on the upstream side, the paper is transported by the pulling assistant. This prevents the paper from becoming loose between the conveying means of each paper feeding unit, thereby suppressing the occurrence of jams. Further, by driving the conveyance means by a DC motor and controlling the conveyance speed by a voltage applied to the DC motor, there is no need to introduce particularly high-precision rotation speed control technology.

〔Example〕

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

FIG. 2 is a schematic diagram showing the overall configuration of the copying machine according to the embodiment. A paper feed unit (3B) with the same configuration as this paper feed unit 3A,
3C are stacked and placed on a dedicated table 4.

The copying machine main body 2 has a known optical system 2a and an image forming section 2b, and an original image obtained by exposing an original placed on a platen glass 5 above the optical system 2a is transferred to a reflecting mirror. The image is formed on the photoreceptor 7 of the image forming section 2b through an optical path 6 consisting of a lens and a lens, and a latent image of the original image is formed on the photoreceptor 7. The latent image formed on the photoreceptor 7 is developed into a toner image by a developing device, and is transferred to the transfer charger 8 position as the photoreceptor 7 rotates. Then, the toner image on the photoreceptor 7 is transferred by the transfer charger 8 onto the transfer paper fed into the copying machine main body 2.

The transfer paper onto which the toner image has been transferred is fixed by a fixing device 9, and the original image is copied onto the transfer paper.

The paper feed unit l-3A on the copying machine main body 2 side and the additional paper feed units 3B and 3C have the same configuration as described above, and are stacked vertically as shown in FIG. Units) Conveyance paths 10A, I formed in 3A, 3B, 3C
The OB and IOC pass through the upper and lower surfaces of each sheet feeding unit 3A, 3B, and 3C, forming one i11* feeding path 10. FIG. 1 is an explanatory view of the main parts of the paper feeding unit. As shown in the figure, transfer paper is placed near the upper end of the paper feed unit 3B following the paper feed unit 3A on the main body side.
Guide members 11a and llb for smoothly guiding to 0B
Intermediate (conveyance) rollers 12a and 12b serving as conveyance means are provided at the upper end of the paper feed unit 3B with a conveyance path 10B in between. These intermediate rollers 1
Minute irregularities are formed on the surfaces of 2a and 12b.

A storage container (tray) 13 is provided in the paper feed unit 3B facing the guide member 11b, and a transfer paper 14b of a type corresponding to the storage container is stored in the storage container 13. A half-moon paper feed roller 15 is disposed as a separating and feeding means, facing the transfer paper located in the uppermost layer of the transfer paper 14b. The half-moon paper feed roller 15 is set at its initial position so that its flat surface faces the top layer of transfer paper.

Further, as shown in a partially enlarged view in FIG. 1, an intermediate sensor 16 is provided near the intermediate rollers 12a and 12b on the downstream side (the side closer to the copying machine main body 2) in the transfer paper conveyance direction. There is.

FIG. 3 shows further essential parts of the paper feeding unit, and FIG. 3(a) is a front sectional view of the essential parts, and FIG. 3(b) is a side view thereof. As shown in the figure, a DC motor 37 is installed inside the housing of the paper feed unit 3B via a bracket 50.
A gear 18 is attached to the rotating shaft of the DC motor 37, and the gear 18 and the idle gear 19 mesh with each other. A gear 20a equipped with a one-way clutch is provided on the intermediate roller shaft 21a.
and a paper feed clutch transmission gear 20b, the gear 20
a is meshed with the idle gear 19. The paper feed clutch transmission gear 20b further meshes with the idle gear 22, and this idle gear 22 further feeds the paper for half a month. Note that the intermediate roller 12b is a driven roller that follows the intermediate roller 12a that is driven by the intermediate roller shaft 21.

In this case, for example, if the rotation speed of the gear 18 fixed to the rotating shaft of the DC motor 37 is 123 rpw+, the roller shaft 21 of the intermediate roller 12a rotates at 123 rpm,
The roller shaft 23 of the half-moon paper feed roller 15 is 55.35rpr
It is set to rotate with @.

Further, when the clutch mechanism 20 is activated, the half-moon paper feed roller 15, which rotates to separate the transfer paper and send it to the conveyance path 10B, rotates once, and then the paper feed drive bracket 2
5 is actuated and separated from the drive system, it stands still while maintaining its original position, and when the next paper feed signal is input, it repeats the same one-rotation operation.

As shown in the control circuit diagram in FIG.
N2 and CN3 connect the paper feed unit 3B in parallel with the control circuit unit 30A of the paper feed unit 3A on the main body side.
, 3C are connected to control circuit units 30B and 30C.

Output port 310 of CPU 31 of control circuit unit) 30
is connected to a logic circuit 32, and the output terminal of this logic circuit is connected to the relay selection drive circuit 33 of the control circuit unit) 30A of the paper feed unit) 3A. The DC power supply 34 of the control circuit unit 1-30 includes a transistor 35 and a diode ZD.

It is connected to a relay circuit 36 consisting of ZD, , ZD, and relays RAI, RA2, and RA3.

A DC motor 37 is connected between this relay circuit 36 and a motor control terminal of an output port 310 of the CPU 31 . Further, the sensors 38 of the paper feed unit 3A are connected to the input port 311 of the CPU 31 of the control circuit unit 30.

The paper feed units 3B and 3C are connected to the control circuit unit 30.
Also, the connecting connector, CN2. It is connected via CN3 in exactly the same way as the paper feed unit 3A.

In such a configuration, when the control circuit unit 30A of the paper feed unit 3A is connected to the control circuit unit 3°,
The detection signals from the sensors 38 become ready to be taken into the CPU 31. At the same time, the CPU 31
A control signal for driving relay RAI is inputted to relay selection drive circuit 33 from.

The relay selection drive circuit is turned on by inputting this control signal.
As a result, relay RAI is energized, and DC voltage V2E11 can be applied to DC motor 37.

Similarly, the connection connector CN of the control circuit unit 30
2. When the optional units (first-stage and second-stage paper feed units) 3B and 3C are connected to CN3, the detection signals from the sensors 38 of each paper feed unit are sent to the CPU 3.
1 can be imported. Then, in the paper feed unit 3B, the relay RA2 is energized, and the DC voltage ■2° can be applied to the DC motor 37, and the paper feed unit 3
At step C, relay RA3 is energized and DC voltage V2.C is applied to DC motor 37. becomes ready to be applied.

As shown in FIG. 2, paper feed units 3A, 3B, 3
Although they are installed in the order of C, in the present invention, the DC voltage v
Each paper feeding unit 3A when zt+t l v and □+V2□ are respectively applied.

Number of revolutions M per unit time of DC motor 37 of 3B and 3C
The following relationship is set between +, Mx, and 'Lly.

Ml ≧M2≧M, ・・・・・・・・・(
1) Figure 5 shows the DC voltage VZfll + in this case.
v2゜.

The relationship between v zn's and the rotational speed of the DC motor 37 is shown, including the variation e in the characteristics of each DC motor (1
) It is designed to satisfy the second condition.

Therefore, the transport speed of the transfer paper in the transport path 10 by the intermediate rollers 12a and 12b of the paper feed units 3A, 3B, and 3C is V, , V, respectively.

■, then the following equation holds true.

■Work≧V2≧■, ・・・・・・・・・(2
) In the above, three paper feed units 3A, 3B, 3t3
It is possible to provide A, 3B...3N,
In that case, the rotational speed of the DC motor and the conveyance speed by the intermediate roller of each paper feeding unit corresponding to equations (1) and (2) are as follows:
Paper feed units 3A, 3B, etc. from the side closest to the copying machine main body 2.
... Assuming that they are arranged in the order of 3N, each is given by the following formula.

N1≧N2≧N,・・・・・・≧NN ・Old・・・・
(3) ■1≧■2≧■3・Old・・≧■8 ・・・・Old・(4) Next, the operation of the copying machine to which the present invention is applied will be explained.

In FIG. 2, when copying is performed on transfer paper stored in the storage container 13 of paper feed unit 1-3C, the selection of paper feed unit 3C is performed manually or automatically on the operation panel (not shown). , place the original on the contact glass 5 and turn on the start button.

In the copying machine main body 2, the original is exposed to light as described above, and a toner image of the original is formed on the photoreceptor 7.

On the other hand, when the start button is turned on, the paper feed units 3A, 3
A voltage VZDI is applied to each DC motor 37 of B and 3C.
+v2゜+VZ. is applied to each DC motor 37
are N,,N,, respectively, per unit time.

Therefore, each rotation speed N+ is adjusted so that this variation range does not overlap.
, Nt, N, are set.

When the DC motor 37 of the paper feed unit 3C rotates, the end of the flat surface of the half-moon paper feed roller 15 comes into contact with the top layer of transfer paper, and as the half-moon paper feed roller 15 rotates, one sheet of the top layer of transfer paper is It is separated and sent out to the conveyance path 10C.

The leading edge of the transfer paper sent out to the conveyance path 10C is moved to the paper feed unit) 3 which starts rotating due to the rotation of the DC motor 37.
It is held between intermediate rollers 12a and 12b of C, and is conveyed along the conveyance path 10 by the rotation of intermediate rollers 12a and 12b. If the intermediate sensor 16 of the paper feed unit) 3G does not detect the copy paper after a predetermined period of time, or if the transfer paper remains detected even after a predetermined period of time has passed, it is determined that a jam has occurred. Then, a jam occurrence warning signal is issued.

The leading edge of the transfer paper is located at the intermediate roller 12a of the paper feed unit) 3B.
, 12b, the transfer paper is held between intermediate rollers 12a,
12b at a faster rate. At this time,
Intermediate rollers 12a and 12b of the paper feed unit 3c on the end side
The portion held between the two is rotated at the conveying speed of the transfer paper by the action of the one-way clutch equipped gear 20a, and is conveyed in a tension-free rotating state. Therefore, the transfer paper passes through the paper feeding unit 3 within the transport path 10 without causing any slack.
It is transported in the A direction. Similarly, the paper feed unit 3A is also transported through the transport path 10A, and the transfer paper is fed to the copying machine main body 2.

In this way, in the copying machine of the above embodiment, the leading edge of the transfer paper is transported in the common transport path 10 at a higher transport speed than the trailing end by the intermediate rollers 12a and 12b of the paper feed unit at the corresponding position. The transfer paper is fed into the copying machine main body 2 without jamming due to slack.

As described above, according to the above embodiment, since the transfer paper is conveyed by pulling, each paper feeding unit 3A is driven independently.
, 3B, 3C intermediate rollers 12a.

It is possible to suppress the occurrence of jams due to variations in the conveyance speed of the conveyor belt 12b. In this case, since there is no need to introduce speed control technology, the paper feeding device also becomes low cost.

Further, it is possible to easily install a required number of paper feed units having the same configuration without performing complicated mechanical connections, and copy a document under desired conditions.

In addition, in the embodiment, a system has been described in which the voltage applied to the DC motor is changed by switching the relay of the relay circuit using the relay selection drive circuit, but the present invention is not limited to the embodiment. For example, a configuration may be adopted in which a voltage signal calculated by a logic circuit is applied to the DC motor in response to a command signal from the CPU, or a configuration in which an operator manually switches the voltage applied to the DC motor.

〔Effect of the invention〕

As is clear from the above description, according to the invention configured as described above, the paper can be conveyed in a pulling manner through the common conveyance path, so that no jam occurs. A low-cost multistage paper feeding device can be provided.

Further, according to the invention as set forth in claim 2 configured as described above, it is possible to realize pull-free paper conveyance with a simple applied voltage control circuit without the need to introduce particularly high-precision rotation speed control technology, and thereby prevent jamming. Figures 4, t, and Q all illustrate a copying machine to which the present invention is applied, and Figure 1 is an explanatory diagram showing the configuration of the main parts. , Fig. 2 is an explanatory diagram showing the overall configuration, Fig. 3 is an explanatory diagram showing the configuration of the drive device of each paper feeding unit, Fig. 4 is a control circuit diagram, and Fig. 5 is a characteristic diagram of the drive motor. .

10...Common conveyance path, 10A, l OB
, IOC...... Conveyance path, 12a, 12b.
・・・・・・・・・Intermediate roller, 13・・・・・・・・・
Storage container, ↓L ox-14b, h 10ka...
・Transfer paper, 15... Half-moon paper feed roller, 3
0... Control circuit unit, 31...
...CPU, 33...Relay selection switching circuit, 34...DC power supply, 36...
・・・・・・Relay circuit, 37・・・・・・DC motor.

Figure 5 vzo3 ZD2 zot VB2 □

Claims (2)

[Claims] (1) A storage container that stores paper, a separating and feeding means that sequentially separates and feeds sheets of paper one by one from this storage container, and conveys the separated and fed sheets by this separation and feeding device. A plurality of paper feed units each having a conveyance means for conveying the paper through a path are stacked, and a common conveyance path is formed by the conveyance path of each of the above-mentioned paper feed units, and the conveyance means of each paper feed unit relays forming a conveyance means, further setting the paper conveyance speed of the conveyance means on the downstream side in the conveyance direction of the common conveyance path so as to always be equal to or higher than the paper conveyance speed of the conveyance means on the upstream side in the conveyance direction;
A multi-stage paper feeding device that separates paper from a storage container of an arbitrarily selected paper feeding unit and feeds the paper through a common conveyance path. (2) The above-mentioned conveyance means are driven by DC motors, and these DC motors are driven by an applied voltage control circuit that sets the applied voltage so that the conveyance speed on the downstream side of the common conveyance path is higher than the conveyance speed on the upstream side. The multistage paper feeding device according to claim 1, wherein the multistage paper feeding device is drive-controlled.