JPH03126959A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a sheet from remaining on an intermediate tray even if the current mode is not a double-sided image forming mode by ejecting a sheet placed on the intermediate tray outside a device if the sheet is confirmed to be placed on the intermediate tray when a power source is turned on or when a double-sided copying mode is not set. CONSTITUTION:The device is provided with a sheet presence or absence detecting means B detecting whether sheets are placed on the intermediate tray. When the power source is turned on or when a double-sided copying mode setting means A does not set the double-sided image forming mode, the sheet presence or absence detecting means B detects that the intermediate tray contains sheets, a paper eject means C feeds them from the intermediate tray and ejects them outside the device without forming an image thereon. Consequently, sheets never remain on the intermediate tray in any modes other than the double-sided image forming mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to image forming apparatuses such as laser printers and copying machines.

[Conventional technology]

An image forming apparatus such as a copying machine is provided with a duplex mode setting means, and when the duplex image forming mode is set by the duplex mode setting means, the sheet on which the image forming process for one side has been completed is once conveyed to an intermediate tray and stored; There is a system in which paper is re-fed from the intermediate tray and image formation processing is performed on the back side.

In such an image forming apparatus, for example, a copying machine, when an operator performs one-sided copying, if the operator presses the copy start key without noticing that duplex copy mode is set, the copying Once the paper has been processed, it is not ejected to the outside of the machine, but is inevitably conveyed to the intermediate tray.

Therefore, in such a case, without setting the original on the contact glass, press the copy start key again in duplex copy mode to make a blank copy of the paper stored in the intermediate tray and remove it from the machine. I was trying to get the paper to eject.

However, if you cancel the double-sided copy mode, make a single-sided copy again, and then finish the operation.

There was a problem in that the paper stored in the intermediate tray remained without being ejected outside the machine.

Therefore, in order to solve this problem, as mentioned above, if the duplex copy mode is canceled while there is paper in the intermediate tray, a message indicating that there is paper in the intermediate tray is displayed, and copying starts in that state. In recent years, copying machines have been provided on the market in which when a key is pressed, the paper remaining in the intermediate tray is ejected from the machine without performing a copying operation.

[Problem to be solved by the invention]

However, even in such copying machines, if the operator turns off the power without performing the above operations,
Alternatively, if the copy start key is not pressed for a long time even though the above message is displayed, the paper may remain in the intermediate tray for a long time, and depending on the surrounding environment, it may absorb moisture, dry out, etc. The paper characteristics (frictional resistance, curl, stiffness, etc.) change, impairing paper feeding and transportability, and then when the copy start key is pressed and the remaining paper is fed from the intermediate tray, the paper does not feed.

There has been a problem in that problems such as jams may occur and the paper may not be smoothly ejected out of the machine.

This invention has been made in view of the above points, and it is possible to automatically eject the paper to the outside of the machine if there is paper remaining in the intermediate tray even though the duplex image forming mode is not set. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the present invention is provided with a duplex mode setting means A for setting a duplex image forming mode, as shown in functional blocks in FIG. 1, and when the duplex image forming mode is set by the means. , in an image forming processing device in which the paper for which image forming processing has been completed on one side is once conveyed to an intermediate tray and stored, and then the paper is re-fed from the intermediate tray to perform image forming processing on the back side, the paper is transferred to the intermediate tray. A paper presence/absence detection means B detects whether paper is stored in the intermediate tray, and a paper presence/absence detection means B detects whether paper is stored in the intermediate tray when the power is turned on or when duplex image forming mode is not set by the duplex mode setting means A. If it is detected that the paper is being printed, a paper ejecting means C is provided which feeds the paper from the intermediate tray and ejects the paper as it is outside the machine without performing any image forming process.

[For production]

According to the image forming apparatus configured as shown in FIG. 1, when the power is turned on or when the double-sided image forming mode is not set by the double-sided mode setting means A,
When it is detected that paper is stored in the intermediate tray, the paper ejecting means C feeds the paper from the intermediate tray and ejects the paper as it is outside the machine without performing image forming processing, so that double-sided image formation is possible. Paper does not remain in the intermediate tray even though it is not in the mode, and the conventional problems described above can be prevented.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to FIG. 2 and subsequent figures.

FIG. 2 is an overall configuration diagram showing a copying machine with an automatic document feeder according to the present invention.

This copying machine with an automatic document feeder includes a main body 1, a table 2, and an intermediate tray 41 that is attached to the main body 1 and that temporarily stacks and stores sheets that have been copied on one side during double-sided copying. It is composed of unit 3 etc.

On one side of the main body 1, a plurality of paper feed trays 4 (only two are shown for simplicity) each containing paper of different paper sizes are removably attached, and on the other side, a copy tray 4 is attached. A sorter 5 equipped with a large number of bins 5a for sorting and stacking output sheets is installed, and the front exterior of the upper part is equipped with various keys and indicators necessary to operate this copying machine, which will be described later. An operation panel 15 is provided.

Furthermore, on the top of the main body 1, there is a J.
Automatically feeds M documents one by one and attaches them to the contact glass 20.
An automatic document feeder (ADF) 5 is attached to the top and is ejected after the exposure process is completed.

Inside this main body 1, there is a photoreceptor drum 8° and a charging section 9.
．． Exposure optical system 10. Developing section 11. Transfer section 12. Fixing section 13. A paper ejection conveyance unit 14 and the like consisting of a conveyance roller and a paper guide plate are provided.

Further, the table 2 is provided with a large paper feed tray 16, which can effectively store paper of a frequently used size.

In the case of automatic double-sided copying, the paper is sent out from the selected paper feed tray by the paper feed roller 18, and is conveyed to the photosensitive drum 8 by the registration roller 19 at a predetermined timing, and the image of the document is transferred to the transfer unit 12. (toner image) is transferred.

After it passes through the fixing unit 13 and is fixed, it is sent to the automatic duplexing unit 3 through the conveyance path 32, where the switching claw 17 is switched to the position shown, and is once stacked in the intermediate tray 41 thereof.

Thereafter, this stacked paper is inserted deeply into the main body 1 into the paper refeed conveyance section 60 which is a part of the automatic duplexing unit 3.
The paper is re-fed through the photosensitive drum 8 and sent to the photosensitive drum 8 again, and the reverse side is copied in the same manner.

Then, when it is ejected from the fixing section 13, this time the switching claw 1
7 is switched to the side of the paper ejection transport section 14, and the paper on which both sides have been copied is sent to the sorter 5 and ejected onto one of the bins 5a.

FIG. 3 is an overall configuration diagram showing the automatic duplex unit 3 of this copying machine.

This automatic duplex unit 3 switches the conveyance path of the paper after fixing to either the paper ejection side or the paper refeeding side using the switching claw 17, and when switching to the paper refeeding side, the paper is transferred to the conveyance path 3.
2 to the stack section 40, which will be described later.
0, and a stack unit 40 having an intermediate tray 41 for once stacking the fed sheets, and a stack unit 40 having an intermediate tray 41 for once stacking the fed sheets, and a stack unit 40 for copying the back side of the sheets stacked on the intermediate tray unit 41 for which one side has been copied. The paper refeeding unit 50 includes a paper refeeding unit 50 that refeeds paper by reversing the transport direction, and a paper refeeding transport unit 60 that transports the paper to be refed toward the photosensitive drum 8 again.

The conveying path 52 of the branching portion 30 is composed of a plurality of conveying rollers and a paper guide plate, and a discharge detection fin 31 for detecting a jam or the like is provided at the end thereof.

A light-shielding plate is integrally formed on the release detection fin 31 and the paper end detection fin 53 (to be described later), for example, at the rear part of the rotating shaft, and when each of the fins is pushed and rotated by the paper, the light-shielding plate is formed. The plate blocks the optical path of the optical sensor (photointerrupter) and changes the detection signal that is input from the sensor to the CPU of the main body control section, which will be described later.

Therefore, the CPU can detect the passage or presence of paper from the respective states of the discharge detection holder 31 and the paper end detection holder 53, which will be described later.

As shown in FIG. 4, which shows an enlarged schematic configuration diagram, and FIG. , a paper shifter that comes into contact with the upper surface of the paper conveyed into the intermediate tray 41 and moves the paper in the direction opposite to the direction in which the paper enters the intermediate tray 41 (in the direction of arrow A in FIGS. 4 and 5). It is composed of a roller 42 and a pair of side fences 43a and 43ib6 that can be moved toward and away from each other until they come into contact with both sides Pb and Pc of the sheet P shown in FIG.

The intermediate tray 41 is formed by side plates 41a and 41b of a predetermined height capable of storing, for example, 50 sheets of paper, and a bottom portion 41c.A solenoid 44 is attached to one of the side plates 41a, and the solenoid 44 is operated. The iron is pivotally supported on a shaft 46 and pivoted to one end of a rank-shaped link 45 so as to be able to swing in the direction of arrow B in FIG.
A paper feeding roller 42 is rotatably attached to the other end.

Further, a motor 47 for actively driving the one-paper feeding roller 42 is built into the side plate 41b, and the output shaft via the speed reduction mechanism rotates the shaft 4B. A belt 71 stretched between J 48 and a pulley 49 integrally fixed to the paper collecting roller 42 rotates the paper collecting roller 42 in the direction of arrow C in FIGS. 4 and 5.

The paper refeeding unit 50 is located at the bottom 4 of the intermediate tray 41 shown in FIG.
The leading edge of paper P stacked in 1c.

A pressure mechanism 80 that makes it possible to re-feed the topmost sheet by pushing it up with a pressure plate 81.

A refeed roller 51 contacts the upper surface of the leading edge of the paper pushed up by the pressure mechanism 80, a transport path 52 formed by a pair of transport rollers and upper and lower guide plates, and It is composed of a paper end detection filler 53 and the like that detects the presence or absence of the paper.

It should be noted that a front plate is provided close to the tip of the pressure plate 81, and is used to align the paper at the tip by bringing the tip of the paper conveyed into the intermediate tray 41 into contact with a vertical wall surface. Side plate 54
is formed integrally with the lower guide plate of the conveyance path 52.

The pressurizing mechanism 80 includes a pressurizing plate 81, a cam plate 83 eccentrically fixed to a rotating shaft 82 that rotates half a rotation when a solenoid (not shown) is turned on, and a cam plate 83 that rotates so that a pin is always in contact with the outer peripheral surface of the cam plate 83. A.1 force is applied, the contact piece 84b rotates in the direction of the arrow around the support shaft 84a, and the contact piece 84b
(
(See also Figures 7 and 8).

FIG. 6 is a perspective view showing the opening system of the side fences 45a, 43b.

The side fences 4'5a and 43b are connected to the intermediate tray 41.
A drive wire 75 is driven by a stepping motor 72 fixed in the side plate 41b and wound around a pulley 73 fixed to its output shaft.The drive wire 75 is wound around a pulley 74 rotatably attached to the side plate 41a. Both ends are connected via a coil spring and stretched in parallel, and one of the parallel parts is attached to the side fence 43a, and the other is attached to the side fence 43b, respectively, with a stopper 76a.

76b.

FIG. 9 is a plan view showing the configuration of the operation panel 15 in FIG. 2.

The operation panel 15 has various operation keys at the bottom, such as a sorter key 869, a double-sided copy key 879, and a page continuous copy key 882.
Magnification setting key 89. Paper selection key 90, density adjustment key 9
1a, 91b, numeric keypad 92, number confirmation key 93. Clear stop key 94, print (copy) start key 95. A mode clear key 961, interrupt key 97, etc. are provided.

Further, a display panel 98 is provided in the upper part of the operation panel 15, and this display panel 98 includes an abnormality display section 98a,
Displays and operation keys such as a document number display section 99a and a document number setting key 99b are provided.

The error display section 98a displays an error message to inform you of a paper jam, lack of developer or toner, or that the copying machine is left open to clear the error condition. Is displayed.

The number of originals to be copied set on the original tray 7 of the ADF 6 shown in FIG. 2, which is set by the original number setting key 99b, is displayed on the original number display section 99a.

FIG. 10 is a block diagram showing the configuration of the control system of the copying apparatus in this embodiment.

A microcomputer (CPU
) 101 is connected to a group of operation key switches 106 of the copying machine via an I10 buffer 104, and also includes mechanical circular state detection sensors 107 and a pulse generator 108 that generates pulses synchronized with the rotation of the photosensitive drum 8. are connected to each other.

Then, the CPU 101 connects the RAM 102. R.O.
M1os, and I10 buffers 104 and 105, respectively.

Furthermore, the I/O buffers 104 and 105 are connected to the display element 111 of the operation board, the mechanical movement system, and the R light via their respective drivers 110 and 112.

It is connected to charging, developing system, wandering paper thread, fixing system, peripheral equipment, etc.

Note that the RAM 102 is backed up by a battery, and its contents are maintained even if the power switch of the copying machine is turned off.

Here, the basic operation of the automatic duplexing unit 3 configured as shown in FIGS. 3 to 8 will be specifically explained.

To perform automatic double-sided copying using the automatic duplexing unit 3 in the copying machine shown in FIG. 2, first turn on the main switch (not shown) of the main body 1 (power on), and then copy using the display panel 98 shown in FIG. After checking the condition, set the original to be copied on the original tray 7 of the ADF 5 shown in FIG. Then, double-sided copy key 8 on the operation panel 15
7 to set the double-sided copy mode, and after setting necessary items such as the number of original sheets, paper size, copy density, etc. using the aforementioned operation keys, the print start key 95 is pressed.

As a result, the control unit in FIG. 10 and the control unit (not shown) in the ADFB start sequence control, and one document is automatically fed from the FX document tray 7 onto the contact glass 20, charged, and While the exposure and development steps are executed, paper corresponding to the selected paper size is fed from the paper feed tray 4 or 16 by the paper feed roller 18 and registration roller 19, and as described above, the paper corresponding to the selected paper size is fed to the photosensitive drum 8. After the original image (toner image) formed thereon is transferred and fixed by the fixing unit 15, the paper on which one side has been copied is conveyed onto the intermediate tray 41 of the automatic duplex unit 3.

At this time, when the leading edge of the paper passes through the release detection filler 31 shown in FIG.
The solenoid 44 shown in FIG. 5 is turned ON, the paper shifting roller 42 is lifted upward by the link 45 and retracted, the motor 47 rotates, and the paper shifting roller 42 rotates in the direction of arrow C.

When the paper is fed onto the bottom 41Q of the intermediate tray 41 and its rear end passes the release detection filler 31 shown in FIG. A solenoid (not shown) is turned OFF, and the paper feeding roller 42 rotating in the direction of arrow C is thereby lowered, and the set state of the pressure plate 81 is released, that is, the cam plate 8'5 is moved to the position shown in FIG. 7, the lever 84 is rotated in the direction of arrow E by a spring force (not shown), and its contact piece 84b causes the pressure plate 81 to move to the bottom 41c of the intermediate tray 41 (FIG. 4). It goes down until it becomes flat.

Then, when the paper shifting roller 42 descends onto the top surface of the paper P and makes light contact with it, the paper is returned in the direction of arrow A, and its leading edge P
a butts against the front side plate 54, as shown in FIG. 7, and the tips thereof are aligned. Then, at the end timing, the solenoid 44 is turned on and rises again, leaving the top surface of the paper P.

Thereafter, this operation is repeated as many times as the number of sheets stacked on the intermediate tray 41.

After that, when the final paper is stacked on the intermediate tray 41,
After a short delay, the stepping motor 72 (FIG. 6) rotates and the opening wire 75 is moved, thereby opening the pair of side fences 43a as shown in FIG.

43b is the home position (position R in the maximum open state)
The paper P is horizontally aligned by moving in the direction of narrowing the gap from there until it comes into contact with both sides Pb and Pc of the paper.

Furthermore, the cam plate 83 of the pressure mechanism 80 rotates half a turn to the position shown in FIG.
pushes up the pressure plate 81, so the leading edge of the paper P on the pressure plate 81 is lifted as shown in FIG. 51 in preparation for the paper refeeding operation from this intermediate tray 41.

Next, when the back side original is set and the print start key 95 is pressed, the paper refeed roller 51 rotates in the direction of arrow G, and the paper reverses its transport direction and is sent to the transport path 52, as shown in FIG. The paper is again sent to the photosensitive drum 8 through the re-feed paper age feeding path 60 shown in FIG.
The sheets on which both sides have been copied are sequentially discharged to the bins 5a of the sorter 5 through the paper discharge conveying section 14.

FIG. 11 is a flowchart of the main routine showing the basic operation of this copying apparatus (under the control of the control section 100).

This routine starts when the copier is powered on, first performs power-on initialization processing, then sequentially executes print pre-processing, copy pre-processing, copy processing, and copy end processing, and then Before returning to the print preprocessing or copy preprocessing for copying, the single-sided copy mode is set by the power-on initialization process.

FIG. 12 is a flowchart showing the print preprocessing subroutine of FIG. 11.

In this print preprocessing, first, it is determined whether the duplex mode flag is ON (duplex copy mode), and then the duplex mode flag is turned on.
If it is in the state, the mode setting process is performed, and then the process proceeds to the print preparation process.

If it is in the OFF state (single-sided copy mode), it is determined whether or not there is paper in the intermediate tray. If not, the process proceeds to the mode setting process, and if there is, it is set as a jogger (paper alignment operation on the intermediate tray). When the processing is completed, the ejection flag is turned on, that is, the flag for feeding the remaining paper on the intermediate tray 41 in Fig. 3 and ejecting it outside the machine without printing is turned on. Proceed to the preparation process.

When the print preparation process is completed, a print condition check process is performed to enable the copy operation, and if printing is possible (print permission flag is ON), the process proceeds to print start check process, otherwise the ejection flag is ON. It is determined whether the state is the same or not.

If the ejection flag is not ON, the process returns to determining whether the duplex mode flag is ON or not, and if it is ON, print start check processing is performed, and as a result, when the print start flag is ON, the main routine shown in Figure 11 is performed. Return to and proceed to the next copy preprocessing routine.
If it is not in the ON state, the process returns to determining whether the duplex mode flag is in the ON state or not, and this process is repeated.

FIG. 13 is a flowchart showing a subroutine of the jogger set process of FIG. 12.

In this jogger set process, it is first determined whether or not the jogger set has been completed, and if it has been completed, the process directly returns to the routine of FIG. 12.

If it is not completed, it is determined whether the stepping motor (hereinafter simply referred to as "motor") 72 shown in FIG. The process proceeds to a determination as to whether or not a sensor (not shown) for detecting the state when the side fences 43a+4'5b are opened to the maximum is in the ON state.

If the home position sensor is not ON, the motor 72 is reversed and the side fence 4 shown in FIG.
3a and 43b are moved in the opening direction, and the process returns to the routine of FIG.

Also, if the home position sensor is turned on,
By rotating the motor 72 in the forward direction, the side fences 43a and 45
b is moved in the direction of narrowing the interval, and at the same time, counting of pulses applied to the motor 72 is started, and the process returns to the routine of FIG. 12.

On the other hand, in determining whether or not the motor 72 is in the normal rotation state, if the motor 72 is in the normal rotation state, the size data of the paper on the intermediate tray 41 is read. This size data is stored in the backed up RAM 102 in FIG.

Next, if the counted number of pulses reaches the number of pulses corresponding to the size data, the motor 72 is turned off, the side fences 4'5a and 43b are stopped at the positions where they touch both ends of the paper, and the jogger is turned off. The setting is completed and the process returns to the routine shown in FIG.

FIG. 14 is a flowchart showing a subroutine of the mode setting process shown in FIG. The processing related to each mode setting such as the mode is sequentially executed, and when the processing is completed, the process returns to the routine shown in FIG. 12.

FIG. 15 is a flowchart showing a subroutine of the print preparation process shown in FIG.
Return to the routine shown in the figure.

FIG. 16 is a flowchart showing a subroutine of the printing condition check process shown in FIG.
When there is no paper on top, the fixing temperature has reached the target value, cleaning has been completed, and toner replenishment has been completed, the print permission flag is turned on and the process returns to the routine shown in FIG. 12.

Further, if any of the above answers is NO, the print permission flag is turned OFF and the process returns to the routine shown in FIG. 12.

FIG. 17 is a flowchart showing a subroutine of the print start check process of FIG. 12.

In this print start check process, it is first determined whether or not the discharge flag is in the ON state, and if it is in the ON state, the print start flag is directly turned ON and the process immediately returns to the routine of FIG. 12.

If the discharge flag is OFF, then it is determined whether or not the print permission flag is ON, and if it is ON, the print start key 95 in FIG. 9 is pressed (print SW is OFF).
N) Determine whether or not it has been done.

Then, when the print start key 95 is pressed, or if the auto print flag is turned on, the print start flag is turned on and the process returns to the routine shown in FIG. 12.

FIG. 18 is a flowchart showing the copy preprocessing subroutine of FIG. 11.

In this copy preprocessing, first turn on the main motor.

Executes print ON initialization processing such as turning on the copying flag, clearing the copy counter, clearing the pulse counter, clearing the paper ejection counter (described later), turning off the copy ready display, and turning off the document set flag, and then clearing the selected source. After starting to feed paper from the paper tray or intermediate tray 41, it is determined whether or not the discharge flag is in the ON state.

Then, if the ejection flag was in the ON state, it remained as is; otherwise, developer supply processing and original paper feeding processing were performed (
At this time, it is assumed that the original is set in the original tray 7 of the ADF 5 in Fig. 2), and then it is determined whether the paper feeding is OK or not, that is, whether the paper is fed in the correct state. , if the paper feeding is OK, it is again determined whether the ejection flag is in the ON state or not.

If the discharge flag is ON, if the discharge flag is OFF, if both the developer supply and original paper supply are OK, the process returns to the main routine shown in FIG. 11 and proceeds to the next copy processing routine.

FIG. 19 is a flowchart showing the copy processing subroutine of FIG. 11.

This copy process includes initial settings and input/output processing.

The abnormality check processing is sequentially performed, and if an abnormality is found, the process proceeds to an abnormality processing routine (not shown).

If there is no abnormality, repeat processing and repeat timing check processing are performed, and if it is a repeat timing, repeat end check processing is performed, and when the repeat is completed, the process returns to the main routine of FIG. 11 and proceeds to the copy end processing routine.

FIG. 20 is a flowchart showing a subroutine of the repeat process in FIG. Return to the routine shown in the figure.

FIG. 21 is a flowchart showing the subroutine of the copy control process in FIG. Return to the routine of FIG. 20.

Therefore, the paper re-fed from the intermediate tray 41 is
The back side is not printed and is discharged to the selected bin 5a of the sorter 5 shown in FIG. 2 installed outside the machine.

Further, if the discharge flag is in the OFF state, the count number of pulses generated by the pulse generator 108 in FIG.
Turn on the exposure lamp when .

Turn on the scanner when it is "40", V' when it is r42J
When the F power is ON and r83J is on, the developing bias is turned ON, and thereafter, each time the count pulse number reaches the set number, a predetermined process is executed one after another, and when the process is completed, the process returns to the routine of FIG. 20.

FIG. 22 is a flowchart showing a subroutine of the intermediate tray control process in FIG. 20. In the intermediate tray control process in FIG. The solenoid 44 for raising and lowering the paper gathering roller is turned off to lower the paper gathering roller 42, and the solenoid for raising and lowering the pressure plate (not shown) is turned on to lower the pressure plate 81.

Next, when the above-mentioned pulse number becomes "↓↓O", the solenoid 44 for raising and lowering the 1st paper feed roller is turned on, and then, when the count value of the paper ejection counter reaches the set number of sheets (original set number of sheets), The aforementioned jogger set process shown in FIG. 13 is performed.

When this is completed, the solenoid for raising and lowering the pressure plate is turned off to raise the pressure plate 81 shown in FIG. 4 in preparation for refeeding paper from the intermediate tray 41. When this is completed, the intermediate tray storage flag is turned ON and the routine proceeds to the routine shown in FIG. 20.

FIG. 23 is a flowchart showing the subroutine of the sensor check process of FIG. 20.

In this sensor check process, first, it is determined whether or not an intermediate tray gate sensor (not shown) that detects the state of the discharge detection filler 31 shown in FIG. 4 is in the ON state.

Then, when the release detection filler 31 is pushed by the paper and rotates, and the intermediate tray gate sensor is turned on, the intermediate tray gate sensor set flag is turned on, and the solenoid 44 for raising and lowering the paper feeding roller shown in FIG. 5 is turned on. After raising the paper feeding roller 42, the process returns to the routine shown in FIG.

On the other hand, if the intermediate tray gate sensor is OFF.

Proceed to determine whether or not the intermediate tray gate sensor set flag is ON, and if it is ON, turn the intermediate tray gate sensor set flag OFF, add "↓" to the count value of the paper ejection counter, and at the same time set the intermediate tray gate sensor set flag to OFF. The ray control counter starts counting the pulses sent from the pulse generator 108 in FIG. 10, and returns to the routine in FIG. 20.

FIG. 24 is a flowchart showing a subroutine of the copy end process of FIG. 11.

In this copy end process, a copy end check process is first performed, and then it is determined whether or not the copying mode flag is in the OFF state, and if it is in the OFF state, it is determined whether or not the discharge flag is in the ON state.

If the ejection flag is not ON, the process directly returns to the main routine shown in FIG. 11 and returns to the print preprocessing routine, and if the ejection flag is ON, it is determined whether or not there is paper on the intermediate tray 41. If there is, the process returns to the main routine and returns to the copy preprocessing routine. If not, the ejection flag and the intermediate tray storage flag are turned off, and then the process returns to the main routine and returns to the print preprocessing routine.

FIG. 25 is a flowchart showing a subroutine of the copy completion check process of FIG. 24.

In this copy completion check process, it is first determined whether the copying flag is ON or not. If it is OFF, the process returns to the subroutine shown in FIG. 24, and if it is ON, then whether the duplex mode flag is ON or not is determined. Determine whether

If the duplex mode flag is in the ON state, it remains as is, and if the duplex mode flag is in the ON state, it is determined whether the back mode flag is in the ON state or not, and if the result is in the ON state,
All sensors placed on the transport path (transport path sensors)
Then, if all the conveyance path sensors are in the OFF state, the back side mode flag and the copying flag are respectively turned OFF, and then the process returns to the subroutine of FIG. 24.

On the other hand, if the back side mode flag is not in the ON state, it is determined whether or not the intermediate tray storage flag is in the ON state, and if it is in the ON state, the back side mode flag is turned ON, and then the copying flag is turned OFF. Return to the subroutine shown in the figure.

As described above, according to this embodiment, the CPU 101 shown in FIG. 10 determines whether or not paper is stored in the intermediate tray 41 based on the detection signal input according to the state of the paper end detection filler 53 shown in FIG. When the power is turned on or when the duplex copy mode is not set, the intermediate tray 41
When it is confirmed that the paper is stored in the intermediate tray 41, the paper is fed from the intermediate tray 41 and is ejected to the outside of the machine without being printed, so that no paper remains in the intermediate tray 41.

Therefore, the conventional problem that paper is left in the intermediate tray 41 for a long time causes the paper characteristics to change due to the influence of the surrounding environment, impairing paper feeding and conveyance performance, is solved. The rate at which problems such as non-feed or jams occur when the remaining paper is fed is greatly reduced.

Although an embodiment in which the present invention is applied to a copying machine has been described, the present invention can be applied to various image forming apparatuses including printers and the like having an intermediate tray.

〔Effect of the invention〕

As described above, according to the present invention, if there is paper remaining in the intermediate tray even though the duplex image forming mode is not set, the paper is automatically ejected to the outside of the machine.

Therefore, the characteristics of the paper stored in the intermediate tray 41 will not change and the paper feeding and conveyance performance will not be impaired.
It is possible to significantly reduce the incidence of problems such as non-feeding and paper jams when feeding the paper.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the basic configuration of this invention. FIG. 2 is an overall configuration diagram showing an example of a copying machine with an automatic document feeder in which this invention is implemented. FIG. 3 also shows an automatic duplexing unit. 4 and 5 are general 811i configuration diagrams showing an enlarged view of the vicinity of the stack part in FIG. 3 and a perspective view of its external appearance. FIG. 7 and 8 are perspective views showing the active system. FIGS. 7 and 8 are explanatory diagrams for explaining the relationship between the positions of the cam plate and the pressure plate of the pressure mechanism 80 in FIG. 3. FIG. 9 is a layout diagram showing the configuration of the operation panel of the copying machine shown in FIG. 2. FIG. 10 is a block diagram showing the general configuration of the control section in the main body of the copying machine, FIG. 11 is a flow diagram showing the main routine of the control operation by the control section in FIG. 10, and FIG. 12 is the same as the one shown in FIG. FIG. 13 is a flowchart showing a subroutine for print preprocessing in FIG. 12; FIG. 13 is a flowchart showing a subroutine for jogger set processing in FIG. 12; Figure 14 is a flowchart showing the subroutine of the mode setting process in Figure 12, Figure 15 is a flowchart showing the subroutine of the print preparation process in Figure 12, and Figure 16 is the subroutine of the print condition check process in Figure 12. Flow diagram showing. FIG. 17 is a flow diagram showing a subroutine of the print start check process of FIG. 12. FIG. 18 is a flowchart showing the copy preprocessing subroutine of FIG. 11. Figure 19 is a flowchart showing the copy processing subroutine in Figure 11, Figure 20 is a flowchart showing the repeat processing subroutine in Figure 19, and Figure 21 is a flowchart showing the copy control processing subroutine in Figure 20. Figure 22 is a flowchart showing the subroutine of the intermediate tray control process in Figure 20, Figure 23 is a flowchart showing the subroutine of the sensor check process in Figure 20, and Figure 24 is the copy end process in Figure 11. FIG. 25 is a flow diagram showing a subroutine of the copy completion check process of FIG. 24. 3...Automatic duplex unit 15...Operation panel 3
1... Release detection filler 40... Stack part 41
...Intermediate tray 42...Paper feeding roller 43a
, 45b...Side fence 44...Solenoid (for raising and lowering the paper feeding roller) 47...
Motor (for rotating the paper feeding roller) 50... paper refeeding section
51... Paper refeed roller 53... Paper end detection filler 54... Front side plate 60... Paper refeed transport section 72... Stamping motor (for side fence movement) 81... Pressure plate 87...Double-sided copy key 95...Print (copy) start key 100...
...Control unit (for the copying machine main body) 101...Microcomputer (CPU) 02...
・RAM 108...Pulse generator j@1 Figure s3 Figure 4 Figure 5 Figure 71! ! 1111 Figure 12 Copy pre-disposal route/To Figure 13 Figure 1 Figure 16 Figure 17 Figure 18 Figure 19 Figure 1120 Figure 21 Figure G cabinet 22 Figure 1q Only CI 824 Figure 21123 Figure 825 Figure pre/ To pre-treatment routine

Claims (1)

[Scope of Claims] 1. A double-sided mode setting means for setting a double-sided image forming mode is provided, and when the double-sided image forming mode is set by the means, the paper on which the image forming process for one side has been completed is once conveyed to the intermediate tray. In the dual image forming apparatus, the paper is stored in the intermediate tray and is re-fed from the intermediate tray to perform an image forming process on the back side. When the power is turned on or when the duplex image forming mode is not set by the duplex mode setting means, when the paper presence/absence detection means detects that paper is stored in the intermediate tray, the paper is removed from the intermediate tray. An image forming apparatus comprising a paper ejecting means for feeding paper and ejecting the paper directly to the outside of the apparatus without performing image forming processing.