JPH0750364Y2 - Automatic document feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic document feeder for an image forming apparatus that includes a platen that supports a document for illuminating the document, and conveys the document on the platen. An automatic original having a conveying member provided to face the platen, a paper feed port through which an original of computer paper fed on the platen passes, and an original discharging unit for conveying the original sent from the platen after illumination is completed. Regarding the feeder.

2. Description of the Related Art It is well known that an automatic document feeder of the above type is mounted and used in an image forming apparatus such as an electrophotographic copying machine or a digital copying machine. With this type of document feeder, in addition to normal sheet documents, long computer paper (hereinafter referred to as CF paper) with continuous pages is automatically fed toward the platen, and after illumination. It can be discharged automatically.

In the conventional document feeding apparatus of this type, even when copying CF paper, the paper is automatically fed from the first page to the platen through the feeding port, and after the illumination of the first page is finished,
Transport the CF paper and stop the second page on the platen,
It was configured to do that lighting.

In the above configuration, when printing is performed on a predetermined area on each page of the CF paper, the predetermined copy paper can be obtained by feeding and copying each page. That is, as illustrated in FIG. 1 (a), the printing portions P ₁ , P ₂ , P are correctly printed at the predetermined positions of the pages 1a, 1b, 1c, ... Separated at the folds 2a, 2b ,. _{When 3} ... Is formed, these prints can be copied without problems to obtain a copy paper C on which an image I is formed at a predetermined position as shown in FIG. 1 (b).

However, in some cases, as illustrated in FIG. 1 (c), the printing is not performed at a predetermined position on each page 1a, 1b, 1c ... Of the CF sheet 1, and the printing portions P ₁ , P ₂ , P ₃ There is a case where ... is formed over two pages. In such a case, the conventional automatic document feeder automatically feeds the CF sheet 1 from the first page, stops the first page at a predetermined position on the platen, and copies it. The copy paper C lacking the image I is obtained as shown in FIG.

To eliminate the above problem, the operator manually sets the first printing portion P ₁ at a predetermined position on the platen to copy only when the first page of the CF sheet 1 is copied, and after that, One page may be automatically fed so that each page can be copied.

For example, when copying the CF paper 1 shown in FIG. 1 (c), the first printing portion P ₁ is placed at a predetermined position on the platen and then copied. After that, one page of CF paper is automatically fed and copied. By doing so, the correct copy paper as shown in FIG. 1 (b) can be obtained from all the printing portions P ₁ , P ₂ , P ₃ .

By the way, in the conventional automatic document feeder, a sprocket hole 3 (see FIGS. 1 (a) and 1 (c)) of CF paper is provided on the downstream side of the platen so that the CF device can be automatically fed page by page. A sensor is provided to detect the number of sprocket holes for one page, and while CF paper is conveyed page by page, the CF paper is stopped each time and copying is performed. The reason for arranging the sensor on the downstream side of the platen is to enable reliable control of conveyance and stop of the last page of CF paper.

However, when the operator manually sets the first page of CF paper on the platen as described above,
The position will be slightly different depending on the position where the printing section P ₁ is formed, and the first page will always be the predetermined reference position on the platen, as in the case of automatic feeding from the first page of CF paper. It is never set. For this reason,
The CF paper sprocket hole set on the platen
In some cases, the sensor installed on the downstream side of the platen may not come into contact with the sensor. In such a case, after illuminating the first page of CF paper, the sprocket hole is detected and the CF
It is impossible to correctly convey one sheet of paper.

If the sensor is provided on the upstream side of the platen in order to solve the above-mentioned problem, a predetermined distance exists between the platen and the sensor, and it becomes impossible to control conveyance and stop of the final page.

OBJECT The invention originates from the above-mentioned novel recognition,
The purpose is that even if the first page of the CF paper is manually set on the platen, the original of the CF paper can be reliably conveyed and stopped for each page including the last page. The purpose is to provide an automatic document feeder of the type stored in.

In order to achieve the above-mentioned object, the present invention provides an automatic document feeder described at the beginning for detecting a sprocket hole of a document on a computer sheet and controlling conveyance and stop of the document on the computer sheet by the detection pulse. A first sensor and a second sensor for detecting whether or not the document on the computer paper is present at a position where it can be detected by the first sensor are provided in the conveyance direction of the document on the computer paper.
It is arranged on the upstream side of the platen so that the computer paper document is fed to a predetermined position on the platen after the second sensor stops detecting the computer paper document.
There is proposed an automatic document feeder which is provided with a control means for controlling conveyance and stop of a computer paper document.

At this time, when the first page of the computer paper original is set on the platen, a reference position for positioning the upstream side portion of the computer paper original in the conveyance direction and the second sensor are set. If the distance between them is l and the length of one page of the computer paper document is L1, then l ≦ L1
And the first sensor detects a predetermined number smaller than the sprocket holes for one page of the computer paper document, it is desirable to reduce the conveyance speed of the computer paper document. .

Further, it is particularly advantageous to provide the paper feed port separately from the paper feed means for feeding a normal sheet document to the platen, and to dispose the transport member on the transport path from the paper feed port to the platen.

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

FIG. 2 is a sectional view showing a part of an electrophotographic copying machine 4 which is an example of an image forming apparatus and an automatic document feeder 5 mounted on the electrophotographic copying machine 4.

A platen 6 made of, for example, transparent glass is fixedly installed on the upper portion of the copying machine 4, and an original fed in is placed on the upper surface of the platen 6 as described later. Below the platen 6, a first scanner 9 including a light source 7 and a first mirror 8 and a second scanner 12 including second and third mirrors 10 and 11 are arranged. These scanners 9 and 12 are shown in the drawing. Move from the home position to the left in the figure. At this time, the original document supported on the platen 6 is illuminated by the light from the light source 7, and the reflected light is reflected by the first, second and third mirrors 8, 10, 11 and then passes through the lens 13, After being reflected by the fourth mirror 14 which is fixedly arranged, a photoconductor (not shown) is reached and an electrostatic latent image corresponding to the original image is formed there. As is well known, this latent image is visualized with toner, and the visible image is transferred onto a transfer paper, whereby a copy paper as shown in FIG. 1 (b) is obtained.

As described above, the illustrated electrophotographic copying machine 4 is provided with the platen 6 for supporting the original for illuminating the original,
The automatic document feeder 5 for the copying machine 4 includes a platen 6
In order to convey the upper document, a conveyor belt 15 which is an example of a conveying member provided facing the platen 6, a sheet feeding means 16 for feeding a normal sheet document to the platen 6, and a sheet feeding device 16 are sent to the platen 6. It has a paper feed port 17 through which a document of CF paper passes, and a document discharge means 18 for conveying the document sent out from the platen 6 after illumination.

The conveyor belt 15 is stretched over a large number of rollers, one of which is a drive roller 19 driven clockwise by a drive motor M2 which is schematically shown in FIG. 2 (that is, in a state where it is separated from the document feeder 5). It is driven to rotate. As a result, the conveyor belt 15 is driven in the direction of the arrow, and the platen 6
The upper document is conveyed.

The conveyor belt 15, the roller therefor, and the document discharge means 18 are covered by a common cover 20, which are integrally rotatably supported by the main body of the copying machine 4 and are rotated in the lifting direction. The platen 6 is opened to the outside, and the document can be placed on the platen 6 by manual operation.

Next, in order to understand the present invention, a normal sheet document is fed by a paper feeding means.
An example of the action of automatically feeding the platen 6 by means of 16 and the configuration related thereto will be clarified.

First, a main switch (not shown) of the copying machine is turned on, and sheet original sheets (not shown) are set on the original set table 21 in a bundle. As a result, the document set sensor 22 of the sheet feeding means 16 is turned on by the leading edge of the sheet document. In this state, if a print switch (not shown) of the copying machine 4 is pressed, based on the paper feeding command generated from the copying machine side,
The automatic document feeder 5 starts operating. That is, the paper feeding means
The 16 call rollers 23, 23 rotate counterclockwise, and the sheet document advances. At the same time, the separating roller 24 rotates counterclockwise, and by the action of the roller 24 and the separating blade 25 pressed against the separating roller 24, only the lowest one sheet original is fed between the pullout roller pair 26. Platen 6
Be transported to.

Each roller 23, 24, 26 of the above-mentioned sheet feeding means 16 is rotationally driven by the drive motor M1 schematically shown in FIG.

When the leading edge of one fed sheet original is placed on the platen 6, the original is conveyed by the conveyor belt 15 driven in the direction of the arrow.
Is transported on the platen 6. Then, when the trailing edge of this document passes the registration sensor 27 of the sheet feeding means 16,
The fact is detected by the sensor 27, and after the detection, the sheet original moves by a predetermined distance, then the conveyance belt 15 stops, and the sheet original stops on the platen 6. At this time, the trailing edge of the sheet document matches the reference position X on the platen 6. Such control is performed by the encoder E2 attached to the drive motor M2.
(FIG. 4).

The scanners 9 and 12 are then activated, as described above,
The original supported by the platen 6 is illuminated by the light source 7, and the copy operation is performed.

When the copying of a predetermined number of sheets of the above-mentioned sheet original is completed, the copying machine side issues a command to feed the next sheet original to the automatic original feeder 5, and at the same time, the sheet original already copied is discharged. Automatic document feeder 5
A paper discharge command is transmitted to. As a result, the next sheet original is fed by the paper feeding means 16, the transport belt 15 is driven again in the direction of the arrow, and the illuminated sheet original is sent out from the platen 6, and the original is continuously discharged. Is discharged outside the device. This operation is continuously performed, and the sheet originals are automatically fed one by one and copied.

The document ejecting means 18 shown as an example in FIG. 2 has an intermediate conveying roller 28 for conveying the document ejected from the platen 6, and when the sheet document is ejected as it is, it is provided on the downstream side of the roller 28. The switching claw 29 is kept in the position indicated by the solid line. Therefore, the sheet original is conveyed as it is to the left side in the horizontal direction by the intermediate conveyance roller 28 and the paper ejection roller 35 on the downstream side thereof, and is ejected to the outside of the apparatus.

When the sheet original should be inverted and discharged, the switching claw 29 is switched to the position shown by the chain line. Therefore, the platen 6
For sheet originals that have exited from the above, follow the route B1, B2 in Fig. 3 (a).
As shown in FIG. 4, the sheet is conveyed by being guided by the switching claw 29 and sandwiched between the first and second reversing rollers 30 and 31 (arrow B1), and then the rotation of these rollers 30 and 31 is reversed. Is discharged out of the apparatus as indicated by arrow B2 in FIG.

An image is also formed on the back side of the sheet original, and when the image is continuously copied, the next sheet original is not fed from the paper feeding means 16 and the first and second sheets are fed as indicated by arrow D in FIG. 3 (b). Turn the roller 3 of the sheet original coming out of the second reversing rollers 30 and 31.
The sheet is wound around 2 and conveyed, passed between the second and third reversing rollers 31 and 33, and fed again onto the platen 6 to make a copy.

The drive motor M3 schematically shown in FIG. 2 is a motor that drives each roller in the above-described document discharging means 18.

In order to improve the copying efficiency, the feeding of the next original may be started before the copying of the sheet original on the platen 6 is finished, and then the previous sheet original on the platen 6 may be discharged. With this arrangement, a part of the previous sheet document is placed on the platen 6 at the time when the next sheet document is stopped on the platen 6, but this sheet document is securely stopped without being stopped by the intermediate conveyance roller 28. Is discharged.

Next, we clarify the operation when copying a CF paper document and the related structure.

In this case, first the CF as shown in Fig. 1 (a) or (c)
The original of the sheet 1 is manually inserted from the front end thereof into a sheet feeding port 17 provided separately from the above-described sheet feeding means 16.
At that time, when the printing portions P ₁ , P ₂ , P ₃ ... Are formed at predetermined positions as in the CF paper 1 shown in FIG. 1 (a),
The first fold 2a is aligned with the reference position X on the platen 6, and the first page 1a of the CF sheet 1 is set on the platen 6. When the printing spot is misaligned as shown in FIG. 1 (c), the fold line 2a is set so as to be displaced from the reference position so that the _first printing portion P1 is correctly copied. That is, the printing parts P ₁ , P ₂
The intermediate part X1 (FIG. 1 (c)) is set to the reference position X. As described above, the reference position X is used for positioning the upstream side portion of the first page 1a of the CF paper 1 on the platen 6 when the first page 1a of the original is set on the platen 6. To be

The remaining CF paper portion coming out of the paper feed port 17 can be placed, for example, by folding it on the table 21 or at another place as shown in FIG.

Since the platen 6 can be exposed by lifting the cover 20 during the above operation, the operation can be easily performed.

When the cover 20 is closed in the above-mentioned state and the main switch and the print switch of the copying machine 4 are pressed, a paper feeding command is issued from the copying machine 4 side to the automatic document feeder 5, but as will be described later in detail, this feeding operation is performed. Depending on the paper command, neither the conveyor belt 15 nor the ejecting means are activated, and the CF paper 1 remains stopped on the platen 6.

In the state where the CF paper is stopped as described above, the first printing portion P ₁ of the CF paper is copied by a predetermined number according to the operation described above, and as shown in FIG. can get.

When the illumination operation for the first printing portion P ₁ is completed, a paper discharge command is issued from the copying machine side, and based on this, the drive motors M2, M3 shown in FIG. In addition to operating in the direction of the arrow, the rollers of the document discharging means 18 also operate. At this time, the switching claw 29 is always kept at the position shown by the solid line in FIG. 2, so that the CF sheet 1 is horizontally conveyed by the intermediate conveying roller 28 and the sheet discharging roller 35. As a result, the printing section P ₂ of the second page of CF paper is conveyed toward the platen 6.

On the other hand, the platen 6 in the original feeding direction of the CF paper 1
Upstream side of the sheet, in the example shown in the figure, between the sheet feed port 17 and the platen 6, the sprocket hole 3 of the original of the CF sheet 1 is detected,
A first sensor 36 for controlling conveyance and stop of the CF paper document by the detection pulse, and a second sensor 36 for detecting whether or not the computer paper document is in a position detectable by the first sensor 36. A sensor 37 is provided. In the illustrated example, the two sensors 36 and 37 are arranged side by side in a direction perpendicular to the paper surface of FIG. At that time, the distance between the reference position X and the second sensor 37 is set to 1 and CF
Each value is set so as to satisfy l ≦ L1, where L1 is the length of one page of the original document. That is, the distance 1 from the position where both sensors 36 and 37 detect the CF paper to the reference position X is set to be equal to or less than the length L1 of one page of the CF paper 1 document (FIG. 1 (a)). -ing

In addition, in the transport path portion from the paper feed port 17 to the platen 6,
Although a guide member (not shown) is provided to guide both side edges of the CF paper 1 and prevent the skew, the CF paper 1
No transport member is provided for transporting the.

As described above, the copy to the first print section P ₁ is completed, and CF
When the conveyance of the paper is started, the first sensor 36 causes the CF paper 1
When the sprocket hole 3 (FIG. 1 (a) or (c) in FIG. 1) formed in the sprocket hole is detected, and the number of detected pulses is one page of the CF sheet 1, for example, 22, the drive motors M2, M
3 stops and therefore CF paper 1 stops. At this time, the second printing portion P ₂ is positioned at a predetermined position on the platen 6.

Then, the second printing portion P ₂ is illuminated and copied, and after the illumination operation is finished, the CF paper 1 is conveyed again in the same manner as described above, and the third printing portion P ₃ is moved to the predetermined position on the platen 6. Stop at the position, and this is copied. In this way, the first sensor 36 detects the sprocket hole 3 and the CF
The printing portion of each page is sequentially copied while controlling the conveyance and stop of the paper, and during this operation, the second sensor 37 always detects the presence of the CF paper.

When the trailing edge of the last page of the CF sheet 1 reaches both sensors 36, 37 and passes through these sensors 36, 37, the first sensor 3
6 cannot detect the sprocket hole 3. Therefore, if this is the case, it will not be possible to control the transport of CF paper and its stop.

Therefore, from the time when the second sensor 37 no longer detects the CF sheet 1, instead of the control by the detection of the first sensor 36, the CF sheet 1 is conveyed and stopped by a control unit including, for example, a timer unit or a pulse generation unit. Is configured to control. That is, from the time when the second sensor 37 no longer detects the CF paper 1, the conveyance of the CF paper by the first sensor 36,
The stop control is automatically switched to the transport and stop control by the control means. By doing so, even if the first sensor 36 does not detect the sprocket hole 3, the CF sheet 1 will be
By stopping the CF paper 1 after a lapse of a predetermined time or after a predetermined number of pulses are generated, the printing portion of the last page can be correctly positioned and stopped at a predetermined position on the platen 6, and the copy is disturbed. Can be done without. After the copying of the printing section of the last page is completed, the entire CF sheet 1 is carried out from the automatic document feeder, and the series of operations is completed.

FIG. 4 is a block diagram of the entire circuit of the automatic document feeder 5 for obtaining the above-described operation.

In FIG. 4, the CP of the copying machine 4 and the automatic document feeder 5
Information is transmitted to the U38 by serial communication, and each of the above-mentioned sensors 22, 27, 36, 37 and other various sensors (not shown in FIG. 2) provided in the document discharging means 18 139, 239, 339.
Is output to the CPU 38 via the input buffer 39. Further, each of the drive motors M1, M2, and M3 described above outputs a motor ON / OFF command from the CPU 38, a speed command for controlling the motor speed (out of 6-bit data from the CPU), and a motor rotation direction. It is configured to be driven via the servo motor circuits S1, S2, S3 to which the forward / reverse command to be determined is input, and to operate according to the command of the CPU 38. Further, the solenoid and the display for activating the switching claw 29 described above are driven by the driver circuit 4 according to a command from the CPU 38.
Driven through 0. Servo motor circuits S1, S2, S3 are
Pulses from encoders E1, E2, E3 attached to drive motors M1, M2, M3 are used for speed control, and pulse information is CP
Supplied to U38. CPU38, based on this pulse information,
Controls the position of the original. Also, some of them are drive motors M1, M
It is also used to detect anomalies in 2 and M3.

The CPU 38 has an analog port (for example, μPD7810 made by NEC), and variable resistors are connected to the analog ports AN1 and AN2, and the resistance value is supplied to the CPU 38 with a resolution of 256. This information is used to control the stop position of the document.
Since there are some variations depending on the individual automatic document feeders, it is assumed that the number of stop pulses to the document reference position X (FIG. 2) after the sheet document passes the registration sensor 27 is 640 in one device. , The value of the resistor VR1 can be changed so that the pulse number is obtained. In software, for example, 600 pulses (fixed value) and 600 + (VR1 analog value) can be adjusted.

Next, the details of the operation flow relating to the control and the stop of the CF paper will be clarified. The mode in which the CF paper is conveyed will be referred to as the CFF mode.

In the "CFF mode check" routine shown in FIG.
Checking whether to enter the mode or not.

First, insert CF paper from the paper feed port 17.
The second sensor 37 that detects the presence of paper is turned on (fifth
(FIG. 5) When the sheet feeding means 16 for feeding a normal sheet original is not in operation (FIG. 5) and the sheet original is not set on the table 21, that is, the original set sensor 22.
When is not turned on (Fig. 5), the operation of CFF mode is started. This indicates that the operation of feeding and copying a normal sheet original is prioritized.

When the above conditions are satisfied, the automatic document feeder 5 transmits a command "with document" to the copying machine 4 side (FIG. 5).
This information indicates that the original has been set on the automatic original feeder 5 on the copying machine 4 side. Therefore, when the print switch of the copying machine 4 is pressed down, the automatic original feeder 5 is displayed.
A paper feed command for feeding the original is transmitted (FIG. 5). When a normal sheet document is to be fed, this signal causes the automatic document feeder 5 to start the sheet feeding operation. However, in the CFF mode, the sheet feeding operation does not start as described above, and the copying machine does not start. CF is sent to the copying machine 4 by the paper feed command from the 4 side.
Send the paper size (Fig. 5). This information is used as information for automatically selecting a transfer sheet on the copying machine side and automatically selecting a copy magnification.

The CFF mode flag is set on the side of the automatic document feeder 5 in response to the paper feed command (FIG. 5). This flag is CFF
It is to check that the mode has been entered.

As described above, the automatic document feeder 5 side apparently does not operate during the operation in the CFF mode even though the paper feed command is received from the copying machine 4. Therefore, it is not necessary for the copying machine 4 side to distinguish between the normal sheet original and the CF sheet 1, and the control mode thereof can be simplified. Of course, CF paper 1
Is sent to the copy machine 4 side, and the CF
It can also be configured to perform control corresponding to the paper.

After checking that the CFF mode flag has been set (Fig. 5), as described above, the first printing section of CF paper 1
Although P ₁ is illuminated and the copy operation is performed, after the illumination is completed, the copy machine 4 sends a paper discharge command to the automatic document feeder 5 to discharge the copied document (see FIG. 5). ). This command causes the automatic document feeder 5 to send CF
Since the operation to convey and stop the paper (CFF operation) is performed, C
Set "1" to FFJBC (CFF operation counter) (5th
Figure). A series of operations thereafter will be described later with reference to FIGS. 7 to 15.

On the other hand, in the "CFF pulse check" routine shown in FIG. 6, it is checked whether the CFF mode flag is set (FIG. 6), and if it is set,
It is checked whether or not the first sensor 36 for detecting the sprocket hole 3 is turned on (FIG. 6). That is, the first
If the detection pulse when the sprocket hole 3 is detected by the sensor 36 of FIG. 16 is as shown in FIG. 16, it is checked whether the sensor 36 is detecting the hole 3 in the ON state or the OFF state. Is done. Here, when the first sensor 36 is off, CFFEGF (CFF edge flag)
Are reset (FIG. 6). If the sensor 36 is in the ON state, it is checked whether or not CFFEGF is set (Fig. 6), and if not set, CFFEGF is set (Fig. 6). At the same time, a counter CFFCNT that counts the number of sprocket holes detected by the first sensor 36 counts the number of holes (FIG. 6). Further, a counter (or timer) CFFJMT for checking whether or not the CF sheet 1 has jammed during its transportation.
Is cleared, which will be described later.

The counting of the sprocket holes and the clearing of CFFJMT by the above-mentioned counter CFFCNT are performed at the leading edge of the sprocket holes 3 as can be understood from FIG. That is, from when the sprocket hole 3 of the CF sheet 1 being conveyed is not present to when the hole 3 is detected, in other words,
It is executed at the rising edge T of the pulse shown in FIG.
Therefore, even if the first sensor 36 is in the ON state, the CFFE
When GF is set, the operations shown in FIG. 6 are not executed, and these operations are always executed at the rising edge T of the pulse. In this way, the number of the sprocket holes 3 can be counted while being detected by the sensor 36.

Next, FIGS. 7 to 15 show the CFF operation counter CFFJB described above.
It is a flowchart which shows what kind of operation is performed according to the count number of C.

As described above with reference to FIG. 5, when the automatic document feeder 5 receives the paper discharge signal (FIG. 5), CFFJBC
Is set to "1", so "CFJO" shown in FIG.
The "B" routine multi-jumps by the number of CFFJBC. If CFFJBC is “1”, “CFJB” shown in FIG. 9 is displayed.
Jump to the 1 ”routine.

In this routine, first, the drive motor M2 for the conveyor belt 15 is
Then, the speed command of the motor M3 for driving the discharging means 18 is set so as to be in the high speed state H, and both motors M2, M3 are turned on. At the same time, the counter CFFCNT that counts the number of sprocket holes 3 detected by the first sensor 36 is cleared and CFFJBC is set to "2" (Fig. 9). The CF sheet 1 is conveyed by such an operation, and the first page of the CF sheet 1 is discharged from the platen 6.

When CFFJBC becomes "2" (see also Fig. 7), "CFJOB"
By the multi-jump of "CFJB2" shown in FIG. Here, every time this routine is entered, the counter CFFJMT for detecting a jam is incremented (FIG. 10), which will also be described later.

Next, when a predetermined number of sprocket holes 3 have been counted, the speeds of the drive motors M2 and M3 are set to low speed L, and CFFJBC is set to "3" (Fig. 10,). The first sensor 36 is CF
When a predetermined number of sprocket holes corresponding to one page of the document on the sheet 1 are detected, the conveyance speed of the document on the CF sheet 1 is reduced. In this example, the length of one page of CF paper 1 is 2
It is assumed that 22 sprocket holes 3 are formed on one page at 2.11 inches, and when the count number reaches 18,
The above operation is executed. The reason why the drive motors M2 and M3 are made to have a low speed before the conveyance of one page of the CF paper 1 is completed is to accurately stop the CF motor 1 at a predetermined position when the CF paper 1 is stopped. The operation when the CFFCNT count number in FIG. 10 is less than 18 will be described later.

When CFJB becomes “3” (see also 7), CFFJMT is incremented as shown in FIG. 11 (this will also be described later).
(Fig. 11). When the counter CFFCNT counts the number 22 of sprocket holes 3 for one page of CF paper (Fig. 11), the drive motors M2 and M3 are braked, the motors are stopped rapidly, and after this processing, CFFJBC is set to "4". Set (11th
Figure).

In the "CFJB4" routine, as shown in Fig. 12, CF paper 1
Stops, the on / off command of the drive motors M2, M3 is turned off, CFFJBC is set to "0", and the initial state is set (Fig. 12).

As described above, the printing portion P ₂ of the second page of the CF sheet 1 is set at a predetermined position on the platen 6, the copy operation is performed, and the above-described operation is continuously repeated.

In FIG. 10, the second sensor 37 for detecting the presence of CF paper, in which the count number of the counter CFFCNT does not reach 18,
Is turned off (FIG. 10), it means that the trailing edge of the last page of the CF sheet 1 has passed the second sensor 37. In this case, the CF sensor 1 and the counter CFFCNT cannot carry or control the CF sheet 1, so that the encoder attached to the drive motor M3, which is an example of pulse generation means, cannot be performed.
E3 (Fig. 4) controls the feeding and stopping of the CF sheet 1. The control by the first sensor 36 and its counter CFFCNT is automatically switched to the control by the encoder E3 which is an example of the control means. That is, in FIG. 10, when it is checked that the second sensor 37 is off, the counter M3TPC that counts the pulses of the encoder E3 is cleared, and the speeds of the drive motors M2 and M3 are set to the low speed state L. At the same time, "5" is set in CFFJBC. In this way, "CFJB5" shown in Fig. 13
Shift to the routine. Note that the motors M2 and M3 are set to the low speed as described above in order to improve the stop position accuracy of the CF sheet 1 also in this case.

In the "CFJB5" routine, it is checked whether or not the above-mentioned counter M3TPC has counted a predetermined number, "44" in this example (Fig. 13). This count is counter M3TP
It corresponds to the distance from when C starts counting pulses to when the print portion of the last page on the CF sheet 1 reaches a predetermined position on the platen 6. Therefore, at this time, the drive motors M2 and M3 are quickly braked and stopped, and the CF sheet is stopped (Fig. 13). Also, CFFJBC is set to "6" (Fig. 13) and a command for no document is sent to the copying machine 4 side to inform that it is the last page of CF paper.

As shown in FIG. 14, in the “CFJB6” routine, the drive motors M2 and M3 are operated at high speed H by the paper discharge command (FIG. 14) sent from the copying machine side after illumination of the last page, and C
F paper 1 is ejected (Fig. 14). Also, set "7" in CFFJBC and set the timer CF to eject the last page.
Clear EDTM (Computer Form End Timer) (Fig. 14).

In the "CFJB7" routine shown in Figure 15, the timer CFEDTM
After the time expires (Fig. 15), the drive motors M2 and M3 are turned off, the CFF mode flag is reset, and CFFJBC
Is set to "0" to be in the initial state, and the series of CFF modes is ended.

The overall flow is as follows: CFFJB0 to CFFJB4 are repeated while CF paper 1 is continuously copied, and CFFJB is used at the last page.
B0, CFFJB1, CFFJB2, CFFJB5, CFFJB6, and CFFJB7 will be processed.

By the way, the counter CFFJMT cleared in the step shown in FIG. 6 is incremented each time the routine of "CFJB2" and "CFJB3" is entered. That is, this counter is cleared each time the first sensor detects the sprocket hole 3, and the first edge is located between the leading edges of the two sprocket holes of the CF sheet that is normally conveyed without jamming.
When the counter counts 50, which is longer than the time it takes to pass the sensor 36, the CF sheet is determined to be a jam. More specifically, in the "CFJB3" routine shown in FIG. 11, the counter CFFCNT
In the state before the number of sprocket holes for one page is counted by 22, the counter CFFJMT is checked, and
(Fig.) When this counts 50 pulses, it is determined that a jam of CF paper has occurred, the drive motors M2 and M3 are turned off, and jam flags used for various jam processes are set (Fig. 11). If the CF paper 1 is conveyed without jamming, it will not count up to 50 pulses and the counter CFFJMT will be cleared before that. For example, if the pitch of the sprocket holes 3 is 1/2 inch,
When the first sensor 36 detects the sprocket hole 36 about every 20 to 30 msec and the counter CFFCNT counts this, and the counter CFFJMT counts up (increments) every 2 to 3 msec, CF If the paper 1 is conveyed normally, CFFJMT is cleared when 10 to 15 pulses are counted, and does not reach more than 50 pulses. When calculated backward, the time interval for detecting hole 3 in CF paper is 10
When 0 to 150 msec or more cannot be detected, a jam is detected,
As described above, the drive motors M2 and M3 are turned off.

The automatic document feeder 5 in this example can reverse and convey sheet originals having images formed on both sides as described above, and the copying machine 4 can transfer images on the front and back sides of the transfer sheet. It has a double-sided copying function that can form On the other hand, the CF sheet 1 has a print formed on only one side thereof, and images are not formed on both sides. In this situation, if the operator wants to make a double-sided copy from CF paper, it should normally operate the operation key to select the copy mode to obtain a double-sided copy from a single-sided original. There is a possibility that a mode for obtaining a double-sided copy from a double-sided original is selected. Therefore, in order to obtain double-sided copy even in such a case, the same processing as when the paper ejection signal shown in FIG. It is desirable to configure so that

As can be seen from the above description, in the automatic document feeder 5 according to the present invention, since the first sensor 36 for detecting the sprocket hole 3 is provided on the upstream side of the platen 6,
In order to obtain a predetermined copy paper as shown in FIG. 1 (b),
Even if the first page of the CF sheet 1 is manually set on the platen 6 and the copy operation is performed while automatically feeding the second and subsequent pages, this can be correctly conveyed page by page and stopped. Moreover, the second sensor that detects the presence of CF paper
After the second sensor 37 stops detecting the CF sheet document, the CF sheet document is conveyed so that the last page of the CF sheet document is sent to a predetermined position on the platen. Since the stop is controlled by the control means, the final page can be correctly set on the platen and copied.

In the above-described embodiment, the pulse generation means mainly composed of the encoder E3 attached to the drive motor M3 and the counter M3TPC for counting the pulses are used for the CF sheet after the second sensor stops detecting the CF sheet. A control unit is configured to control the conveyance and stop of the sheet so that the sheet is fed to a predetermined position above. Of course, as shown above, timer means may be used instead of the pulse generating means such as the encoder E3. Further, instead of the encoder E3, for example, an encoder attached to the drive system such as the conveyor belt 15 or its roller or shaft may be used.

When the CF paper on the platen 6 has been illuminated, a paper ejection command is sent from the copier side, but the drive motes M2 and M3 start operating only in response to this paper ejection command to convey the CF paper. A conveyor belt 15 as an example of a conveyor member and a discharging unit
Drive 18 In other words, in the CFF mode, the CF paper is not conveyed by the paper feed command from the copying machine side. For this reason, the first page of the CF sheet 1 can be manually set on the platen 6 without any trouble. If the CF paper is conveyed by the paper feed command as in the case of copying a normal sheet document, the CF paper is sent out from the platen 6 before starting the copy of the first page, and the predetermined copy should be performed. Is impossible.

Further, in the CFF mode, the CF sheet may be configured to be conveyed by the sheet feeding unit 16 that feeds a normal sheet document.
In this way, since the separation roller 24 and the separation blade 25 that presses against the separation roller 24 are provided in the paper feeding means 16, the CF
When the paper passes between them, it is subjected to a large frictional force, and the paper may be skewed. Even if a normal sheet original is subjected to frictional force from the separating roller 24 and the separating blade 25, it is rare that the sheet original is skewed because the length of the sheet original is short. Each skew accumulates, and finally there is a possibility that a large skew appears.

Therefore, in the illustrated automatic document feeder 5, a CF paper feed port 17 is provided separately from the paper feed means 16 for feeding a normal sheet document to the platen 6, and a separation roller 24 and a blade are provided when the CF paper is conveyed. The friction force of 25 does not act on the CF paper to prevent the skew. A conveying member for conveying the CF sheet, such as a pair of conveying rollers, may be provided between the paper feed port 17 and the platen 6, but since the first page of the CF sheet is manually set on the platen 6. If so, the first page of the CF paper is already located under the conveyor belt 15, so even if the above-mentioned conveyor member is not provided,
The paper can be sequentially transported by the transport belt 15. From this point of view, in this example, no transport member is provided in the transport path from the paper feed port 17 to the platen 6. As a result, the cost of the automatic document feeder 5 can be reliably reduced.

By the way, in the above-described embodiment, the CPU switches the conveyance control and the stop control of the CF sheet by the first sensor 36 to the control by the encoder E3, but FIG. 17 makes it easier to understand the switching means. A specific example configured will be shown.

In FIG. 17, the trailing edge of the last page of the CF sheet 1 is the first and second pages.
Before passing through the sensors 36 and 37, the detection pulse is output from the first sensor 36 which detects the sprocket hole 3 of the CF paper, and this detection pulse is input to the first AND circuit 50. On the other hand, when the second sensor 37 is detecting the CF paper, the output from the sensor 37 becomes L level, which is input to the second AND circuit 51 and also inverted by the inversion circuit 52 to change to H level. It becomes a level and is input to the first AND circuit 50. Further, the pulse output of the encoder E3 of the drive motor M3 is input to the second AND circuit 51 via the frequency divider 53.
The outputs of the first and second AND circuits 50 and 51 are both OR circuits 54.
Is input to the CPU 138 and its output is input to the CPU 138.

In the above-described state, the first AND circuit 50 outputs a pulse corresponding to the pulse output of the first sensor, and this pulse is input to the OR circuit 54, but the output from the second sensor 37 is at the L level. There is no AND output from the second AND circuit 51. Therefore, the OR circuit 54 outputs a pulse signal corresponding to the output of the first sensor 36, which is input to the CPU 138 and counted by the counter. This operation is performed during the period indicated by W1 in FIG. 18 to control the conveyance and stop of the CF paper.

Next, when the trailing edge of the last page of the CF sheet passes through the first and second sensors 36 and 37, the second sensor 37 no longer detects the CF sheet and its output becomes H level. Therefore, the output is input to the first AND circuit 50 at the L level and is input to the second AND circuit 51 as it is at the H level. On the other hand, the output of the first sensor 36 is kept at H level,
The output of the encoder E3 via the frequency divider 53 is input to the second AND circuit 51 as in the case described above.

Therefore, the AND output from the first AND circuit 50 disappears, and the output corresponding to the pulse output of the frequency divider 53 from the second AND circuit 51 is input to the OR circuit 54. Therefore, the OR circuit 54 outputs the same pulse output as the output from the frequency divider 53, which is input to the CPU 138 and counted, and the CF sheet conveyance and stop are controlled. This action is the 18th
It is performed during the period indicated by W2 in the figure.

When the trailing edge of the last page of the CF sheet passes through the second sensor 37 and its output changes from the L level to the H level, the signal is input to the CPU 138, whereby the first sensor 36
The counter that counts the pulse signal output from the counter is switched to the counter that counts the pulse output from the frequency divider 53, and the latter counter counts the pulse output from the frequency divider 53 as described above. It

When the trailing edge of the CF paper passes the sensors 36, 37 as described above, the switching means shown in FIG.
The control by is automatically switched to the control by the encoder E3.

Next, when the illumination of the CF paper on the platen 6 is finished,
A paper discharge command for operating the drive motors M2 and M3 is generated in order to convey the paper, but an example of means for generating the paper discharge command will be described with reference to FIG.

The first scanner 9 shown in FIG. 2 returns to the home position again after illuminating the original on the platen 6, but at this time, the home scanner sensor 60 shown in FIG. 19 is turned on and its output is changed. It is input to the AND circuit 61.

On the other hand, the operator sets the number of copies to be obtained from one original before the start of copying, and the set number is set in the counter 62 shown in FIG.

The copy counter counts the number of copies of a certain page of CF paper, and the set number set in the counter 62 is subtracted.
When the counter 62 detects “0”, a copy end signal is output, and this is input to the AND circuit 61. At this time, the output of the home sensor 61 is also input to the AND circuit 61, so that the AND circuit 61 outputs a paper discharge signal. Based on this, the drive motors M2 and M3 start operating, and the CF sheet is conveyed by one page.

The example in which the automatic document feeder according to the present invention is mounted and used in an electrophotographic copying machine has been described above. However, the automatic document feeder according to the present invention can be used for an image forming apparatus such as a digital copying machine. Is natural.

Effect Since the present invention is configured as described above, the following excellent effects can be obtained.

According to the configuration described in claim 1, even if the first page of the CF sheet is manually set on the platen, the last page of the CF sheet is set to 1
It is possible to reliably convey and stop page by page.

According to the configuration of claim 2, in addition to the above effects,
When the CF paper is stopped, there is an advantage that it can be stopped more accurately at a predetermined position.

According to the configuration described in claim 3, there is an advantage that the skew of the CF sheet can be prevented and the cost of the automatic document feeder can be reduced.

[Brief description of drawings]

FIGS. 1 (a) and 1 (c) illustrate a computer original document and the state of a printing unit formed on the original, and FIG. 1 (b) shows a copy sheet on which an image is copied in a normal position. FIG. 1 (d) is an explanatory view showing a copy paper on which an image is copied with a shift, FIG. 2 is a sectional view showing a part of a copying machine and an automatic document feeder, and FIGS. 3 (a) and 3 (b). ) Is an explanatory view showing a sheet document discharge mode, FIG. 4 is a block diagram of the entire circuit of the automatic document feeder, FIGS. 5 to 15 are CFF mode flowcharts, and FIG. 16 is detection by the first sensor. FIG. 17 is a block diagram showing another configuration example of the switching means, FIG. 17 is a timing chart corresponding to the configuration shown in FIG. 17, and FIG. It is a block diagram shown. DESCRIPTION OF SYMBOLS 1 ... Computer paper, 1a ... 1 item 3 ... Sprocket hole, 5 ... Automatic document feeder 6 ... Platen, 17 ... Paper feed port 18 ... Document ejection means, 36 ... First sensor 37 ... Second sensor, X ... Reference position

Claims (3)

[Scope of utility model registration request] 1. An automatic document feeder for an image forming apparatus, which is provided with a platen for supporting the original for illuminating the original, and is provided to face the platen for conveying the original on the platen. An automatic document feeder having a transport member, a paper feed port through which a document of a computer sheet to be fed onto the platen passes, and a document discharging unit that transports a document fed from the platen after illumination is completed. A first sensor for detecting the sprocket hole of the document and controlling the conveyance and stop of the document of the computer paper by the detection pulse, and whether the document of the computer paper is in a position where it can be detected by the first sensor A second sensor for detecting the temperature is arranged upstream of the platen in the conveyance direction of the original on the computer paper, and the second sensor is A control means is provided for controlling conveyance and stop of the computer paper original so that the computer paper original is fed to a predetermined position on the platen after the original of the computer paper is no longer detected. Automatic document feeder. 2. When setting the first page of a computer paper document on the platen, a reference position for positioning the upstream side portion of the first page of the computer paper document in the conveyance direction, and the second sensor. When the distance between and is 1, and the length of one page of the computer paper document is L1, then l
The transport speed of the original document of computer paper is reduced when the first sensor detects a predetermined number smaller than the sprocket hole for one page of the original document of computer paper, where ≦ L1 is satisfied. Automatic document feeder. 3. The paper feed port is provided separately from a paper feed means for feeding a normal sheet document to the platen, and no feed member is provided in the feed path from the paper feed port to the platen. The automatic document feeder according to claim 1.