JPS6236240A - Sheet feeder of copying machine - Google Patents

Abstract

PURPOSE:To suppress cost as well as power consumption by furnishing a blower in a convergent passage of the downstream part of a suction path for suction of sheets, and by supplying the air from this blower divergently to jets for floating the sheet bored in both sheet feeders for two-side copying and single- sided copying in plural number. CONSTITUTION:Suction means 43, 44a, 44b, and 44c of sheet feeders for both two-side copying and single-sided copying perform suction from suction holes in respective transport belts and connected with a blower 40 through a suction duct 45. The duct 45 is equipped with a neg. pressure adjusting valve 50 and a mechanism relief valve 51. The air from blower 40 is led to jet nozzle 32, 33a, 33b, and 33c via a duct 38 and a divergent duct 36, and the jetting pressure is adjusted with a valve 37. Valves 37, 50 of selected feeders are opened to make single-sided copying, while the valve 37 of another nozzle 32 is opened to make copying on No.1 side in two-side copying, wherein a motor 41 is switched over into high or low speed in accordance with the air supply quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feeding device used in a copying machine capable of copying on both the front and back sides of paper.

Conventional technology: FF # FE m /71 Ma Liao EFx E l
"11j-sesu7b/n-%6" copying machines have become quite popular, but in such copying machines capable of double-sided copying, there is a method that uses air to reliably feed paper one sheet at a time. paper feeders have become widely used (Japanese Patent Application Laid-Open No. 56-256441, also
-56442 etc.)'.

In the double-feeding device, when feeding paper to be copied from the paper feed tray, air is blown onto the paper stacked on the paper feed tray, separating the sheets one by one and separating the sheets so that double feeding does not occur. We make sure to supply one sheet at a time.

An air nozzle for blowing air is attached to each paper feeding device that stores paper of various sizes. The number of protrusions serving as air supply sources for supplying air to the air nozzles corresponds to each paper feeding device.

Furthermore, these paper feeding devices have little need to replace valve parts that change over time, and the structure of the device itself is simple.

Problems to be Solved by the Invention However, in the paper feeding device of the conventional copying machine described above, a corresponding number of expensive blowers are installed for each of the plurality of paper feeders. However, there are problems in that the cost is high and the amount of power consumed increases due to driving a plurality of blowers.

The present invention has been made in view of these problems, and an object of the present invention is to provide a paper feeding device for a copying machine that is inexpensive and consumes less power.

Means for Solving the Problems In order to achieve the object of the present invention, a paper feed device for a copying machine of the present invention includes a plurality of single-sided copy paper feed devices and a double-sided copy paper feed device, and these paper feed devices An air nozzle means that levitates the paper by ejected air and an air vacuum means that adsorbs the paper to the conveying means are installed, the air passages of the respective air vacuum means are joined on the downstream side, and this joining passage is branched to connect the air nozzle means to the respective air nozzle means. The air passage is connected to the air passage, and a blower is interposed in the merging passage.

In a preferred embodiment of the present invention, in addition to the above configuration, an air switching means is provided for selectively supplying air from the blower to the air nozzle means of the single-sided copying paper feeding apparatus or the double-sided copying paper feeding apparatus. Moreover, as a driving means for the blower, a rotational speed switching means that can switch the rotational speed of the blower in at least two stages is installed.

Operation According to the paper feeding device of the present invention, a single blower is used to suck or supply air to the air vacuum means and air nozzle means respectively attached to a plurality of single-sided copy paper feed devices and double-sided copy paper feed devices. With this configuration, the cost of a paper feeding device used in a copying machine capable of double-sided copying can be considerably reduced.

Moreover, the single-sided copy paper feed device and the double-sided copy paper feed device are provided with air nozzle means for blowing air onto the paper sheets on the paper feed tray to reliably separate the sheets one by one from the paper feed tray. Therefore, in terms of preventing double feeding of paper or paper jams, a highly reliable paper feeding device can be provided by using one blower.

Example Embodiments of the present invention will be described below based on the drawings.

Figure 81T1 shows a schematic configuration of an example of a copying machine to which the present invention is applied. In the paper feed section of the main body of the copying machine, single-sided copy paper feeding devices 1 (1a, 1b, 1c) are provided in three stages: an upper stage, a middle stage, and a lower stage. The paper placed on the paper feed tray 2 (2a, 2b, 2c) of each single-sided copy paper feeding device 1 is transported by the drive 0-/L/3 (3a, 3b, 3c) and the driven roll 4 (4a, 4b, The conveyor belt 5 (5a, 5b, 5c) wound around the conveyor roll 6 (6a, 6b, 6c) and the pin l''-lua (7a
, 7b, 7c).
b18c), Particle Transport 9
is supplied to

II by the conveyor belt 10 of the particle transport 9! The second sheet of paper is transported downward in the figure, and is sent to the transfer section of the photosensitive drum 12 via the registration transport 11. ,@Developments on the optical drum 12 are
A transfer corotron transfers the image onto the paper at a predetermined timing. The paper on which the image has been transferred is sent to the fixing unit 11i116 by the vacuum transport 15, where the image is fixed, and then sent to the switching gate 17. At the switching gate 17, in accordance with a command from the copying machine main body, the paper path is switched so that the paper for single-sided copying is transferred to the discharge tray 18, and the paper path for the paper for double-sided copying is switched to be sent to the duplex copying paper feeding device 20.

When double-sided copying is performed, a single-sided copy sheet is supplied onto the paper feed tray 21 of the double-sided copying paper feeder 20, from which the paper is sent out by the bottom feed type paper feeder 20, and then transferred to the particle transport 9 and the resistor. The second image is transferred to the back side of the paper via the ration transport 11 by a transfer section of a transfer drum 12. Thereafter, the transferred image on the paper is fixed via the fixing device 16, and the fixed paper is discharged onto the discharge tray 18 by switching the switching gate 17. In the double-sided copying paper feeding device 20, the paper feed tray 21 thereof is inclined slightly downward to the right as shown in FIG. installed. The sheets stacked on the paper feed tray 21 are conveyed from the lowest sheet by a conveyor belt 24 wound around a drive roll 23 and a driven roll 22, and are sandwiched between a conveyor roll 25 and a pinch roll 26. It is designed to be sent to the particle transport boat 9 via a guide 27.

The double-sided copy paper feed device 1R20 and the single-sided copy paper feed devices 1a, 1b, 1G are connected to conveyor belts 24.5a, 5b, 5.
Air nozzle means 30.31 (31a, 31b, 31
C) is provided.

To explain these air nozzle means 30.31 based on FIGS. 1 and 2, each air nozzle 32.33
(33a, 33b, 33c) A valve 37 is interposed in each of the fume ducts 36 (air passages). A merging passage 38 is formed further upstream of these valves 37, and air nozzles 32.3 are connected to this merging passage 38.
A dual blower 40 for supplying air to the air conditioner 3 is interposed. This dual blower 40 is driven by the driving force of a motor 41 via a drive belt 42.

On the other hand, further upstream of the dual blower 40, air vacuum means 43, 44 (44a, 44b) shown in FIG.
, 44C) via an intake duct (air passage) 45. The air vacuum means 43, 44 are devices that generate negative pressure in suction holes (not shown) formed in the conveyor belt 24.5 to attract paper to the conveyor belt, and the air vacuum means downstream of these devices Each of the ducts 45 is provided with a valve 50 for adjusting the negative pressure generated in the suction holes formed in the conveyor belt 24.5.

A mechanical relief valve 51 as shown in FIGS. 6 and 7 is provided in the middle of the intake duct 45 on the side of the single-sided copy paper feeder 1. As shown in FIGS. When the negative pressure inside the intake duct 45 becomes higher than a predetermined value, the valve body 52 swings clockwise in the figure around the fulcrum a against the spring 53, thereby introducing atmospheric air into the intake duct 45. , plays the role of a safety valve.

Next, the operation of the paper feeding portion of the copying machine will be explained.

i) For single-sided copying: Dual floor 4 is activated by the copy start signal from the copier main unit.
0 rotates, and as shown in FIGS. 1 and 3, the paper feed tray 2a
For example, the paper feed tray 2a selected from 12b and 2C.
The valve 37 corresponding to the paper feeding device 1a is opened, and air is blown onto the paper on the paper feed tray 2a from the air nozzle 33a on the downstream side of the opened valve 37. Paper feed tray 2
The uppermost sheet on top a is attracted to the conveyor belt 5a by the negative pressure generated in the suction hole (not shown) of the conveyor belt 5a, and this attracted sheet passes through the particle transport 9 via the conveyor roll 6a and is transferred to the resist. The toner image is synchronized with the toner image formed on the photosensitive drum 12, and the toner image is transferred onto the paper by the action of the transfer corotron 13.

After that, the fixing bag M is passed through the vacuum transport boat 15.
16, where the transferred image on the paper is fixed. The switching gate 17 is then operated by an electromagnetic solenoid (not shown).
is switched to the position indicated by the broken line in FIG. 1, and the fixed paper is ejected to the ejection tray 18.

11) In the case of copying the first side of double-sided copying: The dual floor 40 rotates in response to a copy start signal, and then, as shown in FIGS. 2a and the valve 37 corresponding to the double-sided copy paper feeder ft20 are opened, and air is supplied from the air nozzle 32 and the corresponding air nozzle 33a of the single-sided copy paper feeder ft20.

The paper fed from the single-sided copy paper feeding device 1 is
Through the process described in i), the image is transferred at the transfer portion of the photosensitive drum 12 and sent to the switching gate 17 via the fixing device 16. The switch 17 is switched to the position shown by the solid line in FIG.

Here, the paper feed tray 21 is slightly inclined as shown in FIG. Then, as shown in FIG. 8, the end guide 55 made of a wear-resistant member is rotated in the six directions of arrows by a motor (not shown), and the air flow from the air nozzle 32 causes a gap between the paper feed tray 21 or the stacked paper and the paper. Friction due to electrostatic attraction acting on the paper is reduced, and the fed sheets are brought closer to the side guides 56, thereby regularly aligning the sheets one by one on the paper feed tray 21. The position of the end guide 55 in the feeding direction is automatically set to match the paper size of the selected single-sided copy paper feed tray 2a.

1ii) In the case of copying on the second side of double-sided copying; the paper that has been copied on one side is stored on the paper feed tray 21 for duplex copying, and from this state, the paper for duplex copying is fed by the second side copy start signal of the paper. Device 20 is started.

That is, as shown in FIG. 5, the valve 37.5o is open, and the lowest sheet of the stacked sheets is placed on the conveyor belt 24, passed through the conveyor roll 25 and the vacuum transport 9, and is exposed to light. It is sent to the drum 12. Then, in the same way as described in i) and ii) above, the image is transferred and fixed on the second side of the paper, and then placed on the output tray.
It is discharged at 8.

The sheets stacked on the double-sided copy paper feed tray 21 in this manner are fed out in sequence starting from the lowest sheet.

In the case of the first side of double-sided copying in ii) above, as shown in FIG.
Since both the valve 37 (37a in this case) in the air nozzle means 31 of the single-sided copy paper feeding device 1 are opened simultaneously, the dual blower 4
0, the required amount of air to be supplied is considerably larger than in the cases of FIGS. 3 and 5. This is done by blowing air from one of the air nozzle means 31 when sending paper from one of the paper feed trays 2, and at the same time aligning the paper that has been copied on one side in the paper feed I-ray 21 for double-sided copying. This is because it is necessary to blow air from the air nozzle means 30 in order to do so. Therefore, in this case, a pulse signal is sent to the drive motor 41 to switch the rotation speed of the dual blower 40 to a high speed rotation side in response to a command from a control circuit (not shown) from the copying machine main body, thereby increasing the rotation speed of the dual blower 40 to a high speed. The air supply amount is increased by switching to the rotation side. The dual blower 40 used in this example is:
Since the blower has a dual blower structure with two coaxial impellers, when the blower rotation speed increases, the suction or ejection pressure of the air vacuum means 43, 44 and the air nozzle means 32, 33 increases simultaneously. There is.

FIG. 9 shows a drive motor 41 of the dual blower 40.
The wiring circuit for driving is shown.

64 is a drive coil, 65 is an excitation coil, and the phase of the current flowing through the excitation coil 65 is advanced by 90 degrees from the phase of the current flowing through the drive coil 64 by a capacitor 66. This causes the drive motor 41 to rotate clockwise. Reference numeral 61 is a switch for turning on and off the power supply 60, and reference numeral 62 is a rotation speed switching relay for switching the rotation speed of the drive motor 41. The switching relay 62 is
In this state, it is on the high speed side, and when reversed, it switches to the low speed side.

Switching of the rotational speed of the dual blower 40 during double-sided copying will be explained with reference to the timing chart shown in FIG. 10. When the copy start signal is detected, the switch 61 for driving the dual blower 40 is turned on, and the relay 62 is switched to the high speed side as shown in the figure. After copying the first side of the paper, when the trailing edge of the final paper is detected by the end detection means of the single-sided copying paper feeding device 1, the relay 62 is reversed from the state shown in the figure, and the rotational speed of the drive motor 41 is set to the low speed side. If a copy start signal is input within 10 seconds thereafter, copying of the second side of the paper is started. If a copy start signal is not input within 10 seconds, the dual blower 40 is temporarily turned off and rotates at a low speed when the next copy start signal is input.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described in detail, one blower is used as an air supply source for the air vacuum means and air nozzle means used in a double-sided copying paper feeding device and a plurality of single-sided copying paper feeding devices. Therefore, by using only one expensive core, power consumption can be reduced and costs can be reduced. Furthermore, by sharing one blower, it is possible to provide a highly reliable paper feeding device that does not cause double feeding of paper or paper jams.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a paper feeding section in an embodiment of a copying machine to which the present invention is applied, FIG. 2 is a schematic configuration diagram showing an air supply system in an embodiment of the present invention, and FIG. 3 4 shows a schematic structure showing the valve state of the air supply system shown in FIG. 2 during single-sided copying, and FIG. 4 shows a schematic structure showing the valve state of the air supply system shown in FIG. Figure 5 is a schematic configuration diagram showing the state of the valve during double-sided copying in the air supply system of Figure 2, and Figures 6 and 7 are partial cross-sections showing the operation of the mechanical relief valve. Figure 8 is a schematic diagram of the paper feed tray of the double-sided copy paper feeder, Figure 9 is a circuit diagram of the drive motor of the dual blower, and Figure 10 is a diagram for explaining the operating state of the copying machine. This is a timing chart. 1 (1a, 1b, 1G)...Single-sided copy paper feeding device,
2 <2a, 2b, 2c) - paper feed tray, 3 (3a,
3b, 3c) --- Drive roll, 4 (4a, 4b, 4
c) ---driven roll, 5 (5a, 5b, 5c)
...Transportation heald, 12...Photosensitive drum, 13
... Transfer: 10 trons, 16... fixing device,
17... Switching gate, 18... Ejection tray, 20... Double-sided copy paper feeding device, 21... Paper feed tray, 30. 31 (31a, 31b, 31 G) - Air nozzle means, 36... Fumarole duct 1~, 37... valve, 38
...merging passageway, 40...dual blower,
43.44 (44a, 44b, 44c) - Vacuum means, 45... Intake duct, 62... Relay.

Claims (1)

[Claims] A plurality of single-sided copying paper feeding devices and a plurality of double-sided copying paper feeding devices are provided, and air nozzle means for levitating the paper by ejected air and air vacuum means for sucking the paper onto a conveying means are attached to these paper feeding devices. A paper feeding device for a copying machine, characterized in that the downstream sides of the air passages are joined, the joining passage is branched and connected to the air passage of each of the air nozzle means, and a blower is interposed in the joining passage.