JPH0733184B2 - Paper feeder - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a sheet feeding device for feeding a sheet to an image transfer unit in, for example, an electronic copying machine.

2. Description of the Related Art Conventionally, as a paper feeding device of an electronic copying machine, for example, automatic paper feeding for automatically feeding paper in a paper feeding cassette and manual paper feeding for manually feeding paper are the same. Some are designed to be performed from the paper feed port.

In such a sheet feeding device, an approximately half-moon shaped sheet feeding roller for feeding the sheet and a registration roller for temporarily stopping the sheet fed by the sheet feeding roller and then sending it to the image transfer portion are used. There is.

A solenoid is provided for each of the paper feed roller and the register roller, and the solenoid controls the drive of the paper feed roller and the registration roller separately.

[Problems with the Background Art] However, in such a conventional paper feeding device, the paper feeding roller and the registration roller can be driven and controlled separately, but since solenoids are used for each, cost is increased, and space and space are required. There is a problem that it is disadvantageous in terms of weight.

Furthermore, even if one solenoid is used, the operations of automatic feeding and manual feeding of the feeding roller and the registration roller are the same, so that the proper operation cannot be performed and reliable feeding is impossible. Met.

[Object of the Invention] The present invention has been made in view of the above circumstances, and it is an object of the present invention to switch and control a sheet feeding roller and a registration roller with a single solenoid. Automatic feeding and manual feeding are suitable for each operation, and reliable feeding is possible. Furthermore, manual feeding is performed without any new feeding mechanism for manual feeding. An object of the present invention is to provide a paper feeding device capable of performing the above.

SUMMARY OF THE INVENTION According to the present invention, when the automatic paper feeding and the manual paper feeding are performed from the same paper feeding port, the driving of the half-moon-shaped paper feeding roller and the registration roller is switched by the operation of one solenoid. In addition, both the automatic sheet feeding from the sheet feeding cassette and the manual sheet feeding from the manual sheet feeding table can be performed by the half-moon shaped sheet feeding roller.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an electronic copying machine equipped with a paper feeding device according to the present invention. That is, reference numeral 1 denotes a housing, and a photosensitive drum 2 which rotates in the direction of the arrow a in the figure is provided at the substantially central portion thereof. A document table 3 for supporting a document is provided on the upper part of the housing 1 so as to be reciprocally movable in the direction of arrow b in the figure. By moving the document table 3 in synchronism with the rotation of the photosensitive drum 2, the light emitted from the exposure lamp 4 is reflected by the document on the document table 3, and the reflected light is convergent optical transmission. An image is formed on the photosensitive drum 2 by the body 5, and is reflected on the photosensitive drum 2 as an inverted image of the original. At this time, by charging the photoconductor drum 2 by the charging charger 6, a reverse image of the document is formed as an electrostatic latent image on the photoconductor drum 2, and the electrostatic latent image is developed by the developing device 7.
The toner is attached so that the toner becomes visible.

On the other hand, a paper feed mechanism 8 for supplying the paper P below the photoconductor drum 2 (image transfer portion 12) is provided below the developing device 7. The paper feed mechanism 8 is detachably attached to a side portion of the housing 1 and holds a plurality of paper sheets P, ...
And a paper feed tray 24 formed on the paper feed cassette 9 for manually feeding the paper P, and a paper feed roller 10 for feeding the paper P from the paper feed cassette 9 one by one. Further, the paper P sent by the paper feed roller 10,
Alternatively, the manually fed sheet P is temporarily stopped, and the inclination of the leading edge of the sheet P is corrected so that the leading edge of the sheet P and the leading edge of the toner image on the photosensitive drum 2 coincide with each other. The configuration is such that it has a registration roller 11 as a conveyance roller that sends it to the image transfer unit 12.
Here, the paper feed roller 10 is, for example, the paper feed cassette 9
The roller is a substantially half-moon shaped roller having a contact portion 10a that comes into contact with the paper P inside and a non-contact portion 10b that does not come into contact with the paper P. Has become.

Then, the paper P conveyed by the registration roller 11
Is sent to the image transfer unit 12. Paper P sent to image transfer unit 12
Is brought into close contact with the surface of the photoconductor drum 2 at the transfer charger 13, and at this time, the paper P by the charger 13 is transferred.
The toner image on the photosensitive drum 2 is transferred by the charging. Then, the residual toner on the surface of the photosensitive drum 2 after the transfer is removed by the cleaner 14, and the static electricity removing lamp is further added.
Afterimages are erased by 15 to return to the initial state. On the other hand, the paper P after the transfer has the peeling charger 16
After being electrostatically separated from the photoconductor drum 2 by the action of, the transfer image is guided along the conveyance path 17 and passes through a pair of heat rollers 18 as a fixing device to heat and fix the transferred image. Then, the paper P after fixing is configured to be discharged to the tray 20 outside the housing 1 by the pair of paper discharge rollers 19.
The photosensitive drum 2, the document table 3, the developing device 7, the paper feed roller 10, the registration roller 11, the heat roller 18, and the paper discharge roller 19 are operated by a motor 21 as a drive source.

In addition, a switch (hereinafter referred to as a paper feed switch) 22 as a detector for detecting a paper feeding state is provided near the registration roller 11 (front side), and further near the paper discharge roller 19 (front side). A switch (hereinafter, referred to as a paper discharge switch) 23 as a detector for detecting the paper discharge state is provided. Each of these switches is provided mainly for detecting a paper jam (also referred to as a jam).

The housing 1 is divided into an upper housing 1a and a lower housing 1b with a transport path 17 as a boundary, as shown by a double-dotted chain line, and both housings 1a and 1b are provided at one end. It is pivotally supported at a fulcrum (not shown) so that the upper housing 1a can be opened at a predetermined angle in the direction of arrow c in the drawing. Where the upper housing
1a includes a photosensitive drum 2, a document table 3, an exposure lamp 4, a converging light transmitter 5, a charging device 6, a developing device 7, a paper feed roller 10, an upper roller of the registration roller 1, a cleaner 14, and a discharge lamp.
15 and the like are provided respectively, and in the lower housing 1b, the paper feed cassette 9, the lower roller of the registration roller 11, the chargers 13 and 16,
Transport path 17, heat roller 18, paper discharge roller 19, tray 20,
A motor 21 and the like are provided respectively.

FIG. 2 shows a document table driving mechanism. That is,
The driving force of the gear 31 directly connected to the motor 21 is transmitted to the electromagnetic clutch 36 via the gears 32, 33, 34, 35 for transmitting the driving force. The electromagnetic clutch 36 is designed to perform three switching operations in the case where the driving force is not transmitted to the pulley 37 by the control signal, in the case where the driving force is transmitted in the forward direction, and in the case where the driving force is transmitted in the reverse direction. Then, the driving force transmitted to the pulley 37 is transmitted to the document table 3 by the wires 38 having both ends fixed to the document table 3, and moves the document table 3. In addition, the pulley
Reference numeral 39 is for making the path of the wire 38 substantially parallel to the platen 3 so as not to come into contact with other portions.

3 to 6 show a document table position detecting mechanism. That is, as shown in FIG. 3, three magnets 41, 42, and 43 are attached to the original table 3 at predetermined intervals in a straight line, and the two maniguenets 44 and 44 are attached to both ends of the magnets 41, 42 and 43 by shifting the phases. 45 are attached. Further, as shown in FIG. 4, reed switches 46 and 47 for detecting the magnets 41 to 45 are attached to the housing 1. The reed switch 46 detects that the magnets 41 to 43 are above it, and the reed switch 47 is the magnets 44 and 45.
It is placed out of phase like a magnet so that it can detect that it is on it.

4 to 6, the positions of the magnets detected by the reed switch 46 are P41, P42, P43, and the positions of the magnets detected by the reed switch 47 are P44, P45. FIG. 4 is a diagram when the document table 3 is located at the home position. The home position is a position where the original table 3 is stopped at the end of the copying operation, and as shown in FIG. 6, only the reed switch 47 is turned on by the magnet 45 in the original table 3 in the arrow direction (hereinafter referred to as forward) of the drawing. When it is at the movement stop position (hereinafter referred to as the original platen limit position) where it can be detected by the operation, the movement starts in the direction of the arrow in FIG. This is detected by the second turn-on, that is, the reed switch 46 is turned on by the magnet 43. Further, FIG. 5 shows a backward movement stop position (hereinafter referred to as a platen start position).
FIG. 6 is a diagram when the document table 3 is located at the position. The original table start position is detected by turning on the reed switches 46 and 47 simultaneously by the magnets 41 and 44.
Further, the reed switch 46 is turned on for the first time after the original platen 3 starts to move forward from the original platen start position and is not at the original platen start position, that is, the magnet 42.
As a result of the reed switch 46 being turned on, the registration roller start position is detected. As described above, since the photoconductor drum 2 and the document table 3 are driven so as to be synchronized with each other, the registration roller 11 is set so that the leading end of the toner image on the photosensitive drum 2 and the leading end of the paper P are aligned. The timing of starting the rotation can be taken from the document table 3 instead of from the photosensitive drum 2. This registration roller
The position to start rotating 11 is the registration roller start position.

FIG. 7 shows the paper feed mechanism 8. That is,
The half-moon-shaped feed roller 10 is attached to a rotary shaft 51, and a sleeve 52 is attached to the rotary shaft 51. The sleeve 52 is connected to a transmission mechanism (not shown) through which the driving force of the motor 21 is transmitted via the spring clutch 53, and the driving force of the motor 21 is transmitted to the rotary shaft 51 via the spring clutch 53 and the sleeve 52. It is supposed to be done. Further, a projection 54 is provided on the inner peripheral portion of the sleeve 52, and projections 55, 56 are provided on the outer peripheral portion with a phase shift as shown in the figure. When one end of the locking lever (control lever) 57 is locked to the protrusions 54 to 56 and the protrusions 54 to 56 are locked by the locking lever 57. The motor 21
The driving force from is not transmitted to the rotating shaft 51. That is, the locking lever 57 is substantially T-shaped, swings left and right about a shaft 58 as a fulcrum, and is driven by a solenoid (hereinafter referred to as a sheet feeding solenoid) 59. When the sheet feeding solenoid 59 is off, the coil spring 60 urges the sheet feeding solenoid 59 in a direction to lock the protrusions 55 and 56 on the sleeve 52.
When is turned on, it is driven in the direction in which the protrusion 54 on the sleeve 52 is locked against the pulling force of the spring 60.

The registration roller 11 is attached to the rotary shaft 61,
One of the rotating shafts 61 is connected to a transmission mechanism (not shown) for transmitting the driving force of the motor 21 via the spring clutch 62, and the driving force of the motor 21 is transmitted to the spring clutch 62.
Is transmitted to the rotary shaft 61 via. The spring clutch 62 is locked by the other end of the locking lever 57 when the sheet feeding solenoid 59 is off. That is, the spring clutch 62
When the paper feeding solenoid 59 is off, the driving force of the motor 21 is not transmitted to the rotary shaft 61 by being locked by the locking lever 57, and when the paper feeding solenoid 59 is on,
When the locking by the locking lever 57 is released, the driving force of the motor 21 is transmitted to the rotating shaft 61 and the registration roller 11 is rotated in the direction of the arrow in the figure.

Further, in FIG. 7, 63 is a detection piece for detecting the angle of the sleeve 52, which is attached to a predetermined portion of the outer peripheral surface of the sleeve 52. A detector 64 for detecting the detection piece 63 is provided at a predetermined portion on the outer peripheral portion of the sleeve 52. The detector 64 optically detects the detection piece 63 and uses, for example, a photo interrupter.
Here, the angle at which the detection piece 63 is detected is determined by the locking lever 57 when the sheet feeding solenoid 59 is turned on when the driving force is transmitted to the spring clutch 53.
The angle is detected from the point where 52 is the closest to the protrusion 54 where the protrusion 54 can be locked without rotating one round to the point where the protrusion 55 is locked by the locking lever 57.

The operation of the paper feed roller 10 and the shift roller 11 by the operation of the locking lever 57 in such a configuration will be described with reference to FIGS. 8 to 11. Although the paper feed roller 10 and the sleeve 52 are on the same axis, the operation will be described here by drawing them to the left and right as illustrated in order to make the operation easier to understand. First, FIG. 8 shows a paper feed roller.
10 is in the reference position. This is the paper feed solenoid
59 is off, the locking lever 57 is pulled by the spring 60 about the shaft 58 as a fulcrum, the projection 55 is locked by the locking lever 57, and the rotation in the direction of the arrow in the figure is stopped. . In this state, the detection piece 63 is as shown in the figure, and the angle is at a marginal angle detected by the detector 64. Further, since the spring clutch 62 is also locked by the locking lever 57, the registration roller
11 has stopped. In this state, the paper feed solenoid 59 is turned on to release the locking of the protrusion 55 by the locking lever 57, and when the sleeve 52 rotates and the detection piece 63 is no longer detected by the detector 64, the paper feed is performed again. Turn off the solenoid 59.
The state at this time is as shown in FIG. By doing so, the sleeve 52 is further rotated to the state shown in FIG. At this time, the paper feed roller 10 also rotates to the angle shown in FIG. 9, and the paper P is sent to a position where the leading end of the paper P is abutted by the registration roller 11 which is locked by the locking lever 57 at this time. Then, from the state shown in FIG. 9, when the registration roller start position is detected, the sheet feeding solenoid 59
When is turned on, the spring clutch by the locking lever 57
The locking of 62 is released and the registration roller 11 rotates, so that the paper P is conveyed so that the front end of the paper P coincides with the front end of the toner image on the photosensitive drum 2. Further, at this time, the locking of the protrusion 56 by the locking lever 57 is also released and the paper feeding roller 10 also rotates, so that the paper P is pushed afterward,
The paper is fed reliably. Then, as shown in FIG.
The protrusion 54 provided at an angle such that the paper P is not pressed by the paper feed cassette 9 or the paper P in the paper feed cassette 9 by the paper feed roller 10 is locked by the locking lever 57. At this time, the registration roller 11 continues to rotate.

Although the above description is for the case of automatic sheet feeding, in the case of manual sheet feeding, the leading edge of the sheet P has already been applied to the registration roller 11 at the time of starting the copying operation, and therefore the registration roller start position is detected. Until the state shown in FIG. 8 is detected, the sheet feeding solenoid 59 is turned on at the time of detection, and the sheet P is pushed to the state shown in FIG. 10 as described above.

Then, the timing when the trailing edge of the paper P has passed the registration roller 11 is detected by turning off the paper feed switch 22, and at that time, the paper feed solenoid 59 is turned off and the eighth
It is returned to the reference position in the figure and prepared for the next copying operation.

It should be noted that FIG. 11 shows that the detector 64 cannot detect the detection piece 63 when the locking lever 57 crosses the protrusion 55. For example, when the power is turned off during the copying operation. The situation shown in FIG. 11 may occur.

FIG. 12 schematically shows the entire control circuit.
That is, it is a microprocessor as the 71 main control unit and controls the entire copying machine. This microprocessor
71, the paper feed switch 22, the paper discharge switch 23, the reed switches 46, 47 (hereinafter,
Signals from the document table switch), the detector 64, and the like are input. And the microprocessor 71
Determines and processes each input signal, and the interface circuit according to the program stored in advance.
Various control signals are output to each control device via 73. For each control signal, the exposure lamp 4, the motor 21, the electromagnetic clutch (hereinafter referred to as the original plate clutch) 36, the paper feeding solenoid 59, and the high-voltage power supply 7 for supplying power to the charging charger 6.
4, a high-voltage power supply 75 for supplying power to the transfer charger 13 and the peeling charger 16, a blade solenoid 76 for pressing the blade of the cleaner 14 against the photosensitive drum 2, and the like, which are operated by control signals To do.

The microprocessor 71 is configured, for example, as shown in FIG. That is, the microprocessor 71
It is a one-chip microprocessor with the architecture shown in Fig. 13. In the figure, 81 is an arithmetic unit (ALU) having an arithmetic determination function, 82 is a read only memory (ROM) for storing a processing program, and 83 is a random memory for storing data.
An access memory (RAM), 84 is an input / output port and an input / output control unit (IO) for transmitting / receiving a signal to / from an external device.
C), 85 is a program counter (PC), 86 is a flag (F
LAG), 87 is an accumulator (ACC), 88 is a stack register (STACK), and 89 is an interrupt control unit (INC).

To briefly explain the operation of the microprocessor 71, the address of the processing program stored in the ROM 82 is designated by the PC 85, the instruction read from the ROM 82 is decoded, and the instruction is executed.
The AG86 stores the carry, borrow, and other states of the result of the operation judgment. The calculation result is stored in the RAM 83 via the ACC87 or an instruction by the ACC87. STACK88 designates the depth of the subroutine, stores the return address of the main routine, and is also used to save the contents of PC85 at the time of interrupt. When an internal interrupt and an interrupt from an external terminal (INT) are requested, the INTC89 terminates the instruction being executed at that point and starts interrupt processing.

When the interrupt processing is started, the contents of the PC 85 are saved in the STACK 88, the address is jumped to a specific address for interrupt processing, the interrupt processing program is executed, and then the main program is restored.

FIG. 14 is a control flowchart when the power of the sheet feeding mechanism 8 is turned on and a general flowchart of the copying operation. Normally, when the power is turned on, it is considered that the paper feed roller 10 is in the standard unit shown in FIG. 8, but it is also possible that the state shown in FIG. 11 may occur when the power is turned off during the copying operation. To be Therefore, it is necessary to control the paper feed roller 10 to be always at the reference position when the power is turned on. This is steps A1 to A9. First, in step A1, the motor 21, which is the driving force for the paper feed roller 10, is rotated. Here, the detector 64
Control changes depending on whether 63 is detected. Step A2 makes this determination. First, the case where the detection piece 63 is detected will be described. The fact that the detection piece 63 is being detected means that at this point, as described above, the sheet feeding solenoid 59
When the switch is turned on, it means that it is necessary to make one round to lock the protrusion 5 by the lock lever 57, and then the paper feed roller 10 also makes one round to supply a new paper P. There is a high possibility that it will end up. Therefore, in this case, the process proceeds to step A6, and if the paper discharge switch 23 is turned on and the paper P is not discharged, the motor is operated until the paper P is discharged.
Perform step A6 to activate 21. Step A7
When the power is turned on, since the paper feeding solenoid 59 is originally off, it is the same as not doing anything. Step A8 includes at least the time T4 required until the projection 55 is locked by the locking lever 57 from an angle at which the detection piece 63 can be detected at least, even when the paper ejection switch 23 is not turned on. This is for rotating the motor 21 to surely bring the paper feed roller 10 to the reference position in FIG. And step
Stop motor 21 at A9.

Next, a case where the detector 64 does not detect the detection piece 63 will be described. For example, this state may be as shown in FIG. 11. It is unlikely that the stop lever 57 will be locked. Therefore, in step A3, the paper feeding solenoid 59
Is turned on, and is rotated until the detection piece 63 is detected in step A4. The detection of the detection piece 63 means that the locking lever 57 locks the protrusion 55 even when the sheet feeding solenoid 59 is turned off, that is, at the position shown in FIG. Further, when the paper feed solenoid 59 is on, the registration roller 11 is rotating. Therefore, when the paper feed switch 22 is turned on and the paper P reaches the registration roller 11, the paper feed switch 22 is turned off. Until that is done, the motor 21 is continuously rotated by step A5, and the motor 21 is rotated by step A6 as described above until further discharging, and the same procedure as described above is performed. The initial check in step A10 is a routine for checking whether or not copying is possible, for example, checking whether or not the temperature of the heat roller 18 is heat fixing possible. If this initial check is completed and the copy is ready, step A1
Transition to the copy standby routine of 1. In this routine, the number of copies is set, and the routine waits until the copy switch is turned on and the copy operation is started. If it is determined in step A12 that the copy switch has been turned on, the process proceeds to step A13, in which the copying process including charging, exposure, transfer, charge removal, and fixing described above is sequentially executed to perform copying.
The copying operation is repeated until it is determined in A14 that copying of the set number of sheets has been completed. In addition, abnormalities such as paper jams are also checked during the copying operation.

Further, the control during the copying operation will be described with reference to the flowchart shown in FIG. When the copying operation is started, the process proceeds to step B1, the blade solenoid 76, the motor 21, the static elimination lamp 15, and the high-voltage power supply 75 (chargers 13 and 16) are turned on, and the process proceeds to step B2. In step B2, it is determined whether or not the document table 3 is at its start position by the document table switches 46 and 47.
If the start position is not reached, the process proceeds to step B3, where a control signal is sent to the document table clutch 36 to move the document table 3 backward, and the process proceeds to step B4. In the above step B2, when the document table 3 is at the start position, the step B3 is skipped and the process proceeds to step B4. In step B4, the original platen 3 is moved to the original platen start position, and when the original platen switches 46 and 47 are both turned on to detect the original platen start position, the process proceeds to step B5. In step B5, it is determined whether or not the manual paper feed mode is set. If the manual paper feed mode is not set, that is, if the automatic paper feed mode from the paper feed cassette 9 is set, the process proceeds to step B6. In step B6, the paper feed solenoid 59 is turned on and the locking lever 57
Then, the locking of the protrusion 55 is released to start feeding, and the process proceeds to step B7. In the manual feed mode in step B5, the paper feed mechanism 8 is not operated here as described above, and the process proceeds to step B7. In step B7, the exposure lamp 4
Lights up, and the process proceeds to step B8. In step B8, a control signal is sent to the document table clutch 36 to move the document table 3 forward, and the process proceeds to step B9. In step B9, the high voltage power supply 74 (charger 6) is turned on, and the process proceeds to step B10. In step B10, it is again determined whether or not the manual paper feed mode is set. In the manual paper feed mode, the paper feed mechanism 8 is not operated yet. In the automatic paper feed mode, the process proceeds to step B11. In step B11, the detector 64 cannot detect the detection piece 63, that is, the locking lever 57 releases the locking of the protrusion 55, and the time when the sleeve 52 and the sheet feeding roller 10 start to rotate is detected and step B12 Proceed to. In step B12, the paper feeding solenoid 59 is turned off and the protrusion 56
Is locked and the process proceeds to step B13. In step B13, the registration roller start position described above is determined, and step B14
Proceed to. In step B14, it is determined whether or not the paper feed switch 22 is turned on. If it is not turned on, step B15
Proceed to. In step B15, it is again determined whether the manual paper feed mode is set. In the manual feed mode, the feed mechanism 8 has not been operated yet, so the feed roller 10 is at the reference position shown in FIG. Therefore, the normal copy operation stop routine (step B23 described later)
~ 25). On the other hand, if it is not in the manual paper feed mode, it means that the paper was not fed normally even though the paper feed mechanism 8 is already in operation, so an error process is performed. By the way, if the paper feed switch 22 is turned on in step B14, it means that the paper is being fed normally, so the process proceeds to step B16. In step B16, the sheet feeding solenoid 59 is turned on to rotate the registration roller 11, and the process proceeds to step B17. Normally, the paper feeding solenoid 5
The time to turn off 9 is the time when the paper feed switch 22 is turned off and the paper P has finished passing through the registration rollers 11 as described above. In step B17, the platen glass 3 is moved to the platen switch 4
It is judged whether or not it has moved to the original platen limit position which is detected by turning on only 7 and when it is moved, the entire surface of the original document is exposed and charging of the photoconductor drum 2 becomes unnecessary, so the process proceeds to step B18. In step B18, high voltage power supply 74
Off, and proceed to Step B19. In step B19, a control signal is sent to the document table clutch 36 to move the document table 3 backward, and the process proceeds to step B20. In step B20, the exposure lamp 4 is turned off, and the process proceeds to step B21. Step B21
Then, it is determined whether or not the platen 3 has moved to the home position detected by the platen switch 46, and if it has moved, the process proceeds to step B22. In step B22, it is judged whether or not copying of the set number of sheets is completed. If not, step B4
Then, the copying operation described above is repeated, and if the copying operation is completed, the process proceeds to step B23. In step B23, the platen clutch
A control signal is sent to 36 to stop the platen 3, and step B2
Go to 4. At step B24, it is judged by the signal from the paper discharge switch 23 whether or not the copied paper P is completely discharged, and when the paper is completely discharged, the routine proceeds to step B25. Step B
At 25, the high-voltage power supply 75, the static elimination lamp 15, the motor 21, and the blade solenoid 76 are turned off to end the copying operation,
The copy standby state shown in FIG. 14 is entered.

In the control of the copying machine of the present invention, the microprocessor 71
The internal interrupt of is used. This interrupt process is set to be repeated at a constant cycle. This is the 16th
Explaining with reference to the drawing, when the power is turned on, the main program of the programs normally stored in the ROM 82 is executed. However, for example, by setting INTC89 so that an internal interrupt is generated every 12 msec from the start of the copy operation, 12 msec from the start of the copy operation.
When the time has passed, the main program is suspended, the interrupt program is executed, and after the interrupt program ends, the main program is executed again. Furthermore, 12m se
The flow of the program is such that the interrupt program is executed when c has elapsed, that is, 24 m seconds after the start of the copying operation.

By the way, as described in the explanation of FIG. 14, an abnormality such as a paper jam is also checked during the copying operation, and the following will explain the paper jam check of these abnormalities.
The paper jam check is performed by an interrupt program that is repeatedly performed at regular intervals. This will be described with reference to the flowchart shown in FIG. 17. Step C1
~ C4, C5 ~ C8, C9 ~ C11 each perform one type of paper jam check. In steps C1 to C4, the paper feed switch 22 is turned on for the fed paper P, and the paper feed switch 22 is turned on even if the registration roller 11 is rotated and the paper P is conveyed, but the paper feed switch is not operated for a predetermined time T1. It is an abnormal check that 22 does not turn on. That is, if the interrupt period is t,
If it is detected in step C2 that the registration roller 11 is turned on after the paper feed switch 22 is detected to be turned on in step C1 (step S3), step C3
Add "1" to the timer set in RAM83 by (initial value of timer is 0). Since an interrupt is generated every t here, an address in the RAM 73 can serve as a timer. Whether or not the value of this timer has become larger than the value of T1 / t is judged in step C4 every time "1" is added, and if it has become larger, that is, even if the registration roller 11 is rotating, it is supplied. It means that the paper switch 22 is on for T1 or more, and since it is abnormal, error processing is performed. Steps C5 to C8 are performed for a certain time even though the registration roller 11 is rotated and the paper P is conveyed.
Even if T2 elapses, the leading edge of the paper P reaches the paper discharge switch 23 and the switch 23 does not turn on. For example, the photosensitive drum 2
The abnormality check is performed such that the sheet P is not normally peeled from the sheet, or the sheet P is not normally conveyed to the heat roller 18. That is, from detecting the turning on of the registration roller 11 in step C5 to detecting that the paper discharge switch 23 is turned on in step C6 is monitored by the timer set in the RAM 83 as in steps C1 to C4. In step C8, it is determined whether or not the value of the timer is larger than T2 / t. If the value is large, the above-mentioned abnormality is detected, and error processing is performed. Step C9 ~
C11 is an abnormality check that the sheet P is not discharged even if a certain time T3 has elapsed after the sheet discharge switch 23 is turned on, that is, a sheet jam occurs near the sheet discharge switch 23 and the sheet P is not discharged. That is, if it is normal in steps C5 to C8, the paper ejection switch 23 is turned on, so if it is detected in step C9, the paper ejection switch 23 is turned on by the timer set in the RAM 83 as in steps C1 to C4. The time being monitored is monitored, and it is judged in step C11 whether or not the value of the timer has become larger than T3 / t.

Next, the error processing will be described with reference to the flowchart shown in FIG. If an error is detected, the step
At D1, the third document is stopped, and the exposure lamp 4, charging charger 6, transfer charger 13, and peeling charger 16 are turned off. At the time when this error is detected, the positional relationship between the stop lever 57 and the projections 55 and 56, that is, the angle state of the paper feed roller 10 is unknown. Therefore, steps D2 to D4 to set the reference position in FIG. D7 takes place. If the detector 64 detects the detection piece 63 in step D2, it is the position where the protrusion 55 is locked by the locking lever 57 even if the paper feeding solenoid 59 is turned off. Turn off 59 (originally the feed solenoid
It is the same as doing nothing when 59 is off), at least until the protrusion 55 is locked by the locking lever 57 from the marginal angle at which the detection piece 63 can be detected as when power is turned on. During time T4, the motor 21 continues to rotate and is reliably set to the reference position. If the detection piece 63 is not detected in step D2, the position shown in FIG. 11 can be considered. Therefore, in step D3, the sheet feeding solenoid 59 is turned on and the protrusion 54 is locked by the locking lever 57. Be able to lock. Then, the position is almost as shown in FIG. 10, and when it is judged in step D4 that the detection piece 63 has been detected, the locking lever 57 moves the protrusion body.
In order to set 55 as the reference position for locking, steps D5 and D6 are executed as in the case where the detection piece 63 is detected, and the motor 21 is stopped in step D7. Further steps
The static elimination lamp 15 is turned off at D8, the blade solenoid 76 is turned off at step D9, and the blade of the cleaner 14 is separated from the photosensitive drum 2. Then, in step D10, a paper jam is displayed, and other functions are stopped.

[Effects of the Invention] As described in detail above, according to the present invention, the switching between the sheet feeding roller and the registration roller can be controlled by a single solenoid. It is possible to provide a paper feeding device capable of performing appropriate operations, ensuring reliable paper feeding, and performing paper feeding without any new paper feeding mechanism for manual paper feeding.

[Brief description of drawings]

FIG. 1 is a view for explaining an embodiment of the present invention. FIG. 1 is a schematic vertical sectional front view of an electronic copying machine, FIG. 2 is a side view showing a document table driving mechanism, and FIGS. FIG. 7 is a diagram for explaining the document table position detecting mechanism, FIG. 7 is a perspective view showing the main part of the paper feeding mechanism, and FIGS. 8 to 11 are diagrams for explaining the operation of the paper feeding mechanism. FIG. 12 is a block diagram schematically showing the overall control circuit, FIG. 13 is a configuration diagram of a microprocessor, FIG. 14 is a control flowchart at power-on and a general flowchart of copying operation, and FIG. 15 is a copying operation. FIG. 16 is a control flowchart, FIG. 16 is a flow chart of a program including a microprocessor interrupt, FIG. 17 is a flowchart for detecting a paper jam, and FIG. 18 is a flowchart for error processing when a paper jam occurs. 2 ... Photosensitive drum, 3 ... Original platen, 4 ... Exposure lamp, 7 ... Developing device, 8 ... Paper feeding mechanism, 9 ... Paper feeding cassette (paper storage unit), P ... Paper, 10 ...... Paper feed roller, 11
...... Registration roller (conveying roller), 12 ...... Image transfer section,
21 …… Motor, 22 …… Paper feed switch, 23 …… Paper feed switch, 24 …… Bypass feeder, 52 …… Sleeve, 53 …… Spring clutch, 54 ～ 56 …… Protrusion, 57 …… Stop lever (control lever), 59 ... Paper feeding solenoid, 62 ... Spring clutch, 63 ... Detection piece, 64 ... Detector, 71 ... Microprocessor (main control unit).

Claims (1)

[Claims] 1. A paper feed cassette for storing paper, a manual paper feed tray formed on the paper feed cassette for feeding manual paper, and provided to face the paper storage surface of the paper feed cassette. During rotation, a part of the circumference is placed on the uppermost portion of the sheet feeding cassette by contacting the sheet placed on the uppermost portion of the sheet feeding cassette or the sheet manually fed on the manual feeding tray. A paper feed roller with a half-moon-shaped cross section that feeds the placed paper or the paper manually fed to the manual paper feed tray, and the paper fed by the paper feed roller is arranged after the paper feed roller. When the registration roller that further conveys the paper after it is positioned and the automatic paper feed mode for feeding paper from the paper feed cassette are set, the paper is fed by the paper feed roller after the rotation of the paper feed roller is started. The rotation of the paper feed roller is temporarily stopped when the paper is rotated to the first angle at which the paper reaches the registration roller, and then the rotation of the paper feed roller is restarted so that the paper feed roller is set to the paper feed cassette. The rotation of the paper feed roller is stopped at the time when the paper is rotated to a second angle at which the paper is not placed, and when the manual paper feed mode for feeding paper from the manual paper feed tray is set, the paper feed is performed. Rotation amount control means for stopping the rotation of the paper feed roller when the paper feed roller rotates to the second angle at which the paper feed roller does not contact the paper placed in the paper feed cassette after the roller starts rotating; A sheet feeding device comprising: