JP2930817B2 - Automatic document feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder, and more particularly to an automatic document feeder installed on an electrophotographic copying machine for feeding, feeding, stopping and discharging a document on a platen glass.

[0002]

2. Description of the Related Art In recent years, in order to improve copy efficiency, a copying system has been widely constructed by combining an electrophotographic copying machine with an automatic document feeder. In such a copying system, a pre-step mode has been developed. In the pre-step mode, if the size of the document is less than half the area of the platen glass, strictly speaking, the length of the document is less than half the distance from the exposure reference point on the downstream side in the transport direction to the entrance of the platen glass. when it, as shown in FIG. 35, and conveyed to the exposure position where the tip of the document D ₁ is the tip of the exposure reference point O navel position, intermediate reference points of a substantially central portion of the platen glass 29 for the next document D ₂ O 'is conveyed to a pre-step position where the tip of the navel is positioned, keep feeding to further the next document D ₃ is the inlet section (first-out reference point P) of the navel tip of the platen glass 29 positioned. Thereafter, the originals are sequentially and intermittently conveyed to P, O ', and O. In the pre-step mode, the time required for document exchange is the time required to transport the document by approximately half the length of the platen glass 29, which greatly contributes to maintaining good copy productivity.

In the pre-step mode, the distance PO 'is equal to the distance OO', and the original is step-feeded by the distance (PO '= OO') by the transport belt. As shown in FIG. 36, the document D ₂ is overshoots only from exposure reference point O [Delta] x, the original D ₃ that is conveyed by the same conveyor belt also becomes possible to overshoot the intermediate reference point O 'by [Delta] x. At this time, when the next document D ₄ to the first-out and fed to the pre-output reference point P, the distance to convey the document D ₃ to the exposure reference point O becomes O'O-Δx, the next document D ₄ intermediate reference point It stops at O 'just before Δx. As described above, the variation in the conveyance amount due to the belt is accumulated, and the document replacement time may be increased. If the document exchange time is not performed within a preset time, the copying speed will be reduced. Therefore, it is desirable that the document replacement time does not vary, especially does not increase.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic document feeder capable of preventing the accumulation of variations in document exchange time in the pre-step mode. In order to achieve the above object, an automatic document feeder according to the present invention includes, in addition to a control unit for executing a pre-step mode, an error in a leading end stop position of a document conveyed to a pre-step position on a platen glass. And a means for correcting the position where the next document waits at the entrance of the platen glass in accordance with the error detected by the detecting means.

[0005] As shown in FIG. 37, the document D ₃ that is conveyed to the pre-step position has gone too far by [Delta] x (error detection value) with respect to the intermediate reference point O ', the leading edge of the next document D ₄ first out The vehicle is stopped so as to exceed the reference point P by Δx (correction value). Next document exchange operation the document D ₃ is the tip is performed so as to be positioned in the exposure reference point O, this time Δx only following a first-out feeding position is corrected document D ₄ is the tip of the intermediate reference point O 'Will be positioned correctly.
If the error at the intermediate reference point O ′ is −Δx, the correction value of the advance feeding position of the next document is also −Δx.

According to the present invention, even if the transport amount (stop position) of the document on the platen glass by the transport belt varies, the variation accumulates at the stop position of the next document sent to the platen glass. Therefore, in the pre-step mode, it is possible to minimize the variation in the document exchange time. Further, in the automatic document feeder according to the present invention, in advance feeding, the document is made to stand by so that the leading end thereof is located at a predetermined advance reference point, and the leading end stop position of the document transported to the pre-step position is set. Timing of feeding the document from the advance feeding position according to the error,
Alternatively, the speed at which the document is sent from the advance feeding position may be corrected.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic document feeder according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an automatic document feeder 50 (hereinafter, ADF) according to an embodiment of the present invention.
), The copying machine body 1 and the sorter 90 are shown.

At substantially the center of the copying machine main body 1, a photosensitive drum 10 is installed so as to be rotatable at a constant peripheral speed v in the direction of arrow a. Around the photosensitive drum 10, along a rotation direction thereof, a main eraser 11, a charging charger 12, a sub-eraser 13, a developing device 14 using a magnetic brush system, a transfer charger 15, and a paper separating charger 1.
6. A blade-type cleaner 17 is provided. Further, an optical system 20 is disposed above the photosensitive drum 10.

The photoreceptor drum 10 has a photoreceptor layer on its surface, and is rotated in the direction of the arrow a to form a main eraser 11, a charger 12 and a sub-eraser 13.
As a result, the image of the document set on the platen glass 29 is exposed by the optical system 20. The electrostatic latent image formed on the photosensitive drum 10 by the exposure is converted into a toner image by the developing device 14.

The optical system 20 scans an image of a document set on the platen glass 29 on the photosensitive drum 10 directly below the platen glass 29. That is, at the time of image scanning, the exposure lamp 21 and the first mirror 22 are integrated with the peripheral speed v of the photosensitive drum 10 (constant irrespective of the same magnification or variable magnification) by v / m (m: copy magnification). Arrow b at speed
Move in the direction. At the same time, the second mirror 23 and the third mirror 24 move in the direction of the arrow b at a speed of v / 2m. When the copy magnification is changed, the projection lens 25 moves on the optical axis and the fourth mirror 26 swings to correct the optical path length.

The copy sheets are accommodated in an upper sheet feeding section 31 and a lower sheet feeding section 34, and are fed one by one from one of them based on an operator's selection. Each paper feed unit 31, 3
4 is provided with paper feed rollers 32 and 35, and separation rollers 33 and 36 composed of a forward rotation roller and a reverse rotation roller.
The paper fed from the upper paper feed unit 31 is transported by a transport roller 37.
It is sent out to the timing roller 38 installed immediately before the image transfer section through b and 37c. Sheets fed from the lower sheet feeding section 34 are transport rollers 37a, 37b, 37c.
To the timing roller 38.

Immediately above the upper paper feed unit 31, both sides /
An intermediate tray 47 for processing the composite copy is provided. The sheet re-supplied from the intermediate tray 47 by the sheet re-supply roller 48 and separated by the separating roller 49 is sent out to the timing roller 38 through the transport roller 37c. The sheet sent to the timing roller 38 once waits here, and is sent to the transfer section by turning on the timing roller 38 in synchronization with the image formed on the photosensitive drum 10. The paper is brought into close contact with the photosensitive drum 10 at the transfer section, and the transfer charger 15
The toner image is transferred by the corona discharge from the photosensitive drum 10 and separated from the photoreceptor drum 10 by the AC corona discharge from the separation charger 16 and the strength of the paper itself. Thereafter, the sheet is sent to the fixing device 40 through the conveyor belt 39,
The toner is fixed, and is stored in the sorter 90 through the transport rollers 41 and 42.

On the other hand, the photosensitive drum 10 keeps the arrow a even after the transfer.
Then, the remaining toner is removed by the cleaner 17 and the remaining charge is erased by the main eraser 11 to prepare for the next copy process. In the composite copy mode, the paper on which the image of the odd-numbered original has been transferred is changed in the paper passing direction downward by the paper passing switching claw 43, and
4, 45, and 46 are stored on the intermediate tray 47. In the two-sided copy mode, the paper is
And is switched back by reversing the transport roller 42, the paper feed direction is changed downward by the switching claw 43, and the transport rollers 44 and
5 and 46 are stored on the intermediate tray 47. Thereafter, the sheet is re-fed from the intermediate tray 47 in order to double-sided / composite copy the image of the even-numbered document.

By the way, in the copying machine body 1, the copying process is started and the first sheet is
When the printer stands by just before 8, the advance processing is performed in which not only the second sheet but also the third sheet is fed to the sheet feed path in advance. For example, in the paper feeding from the lower sheet 34, second sheet P ₂ Following first sheet P ₁ is fed to the feeding path, further the third sheet P ₃ Also transport roller 3
Paper is fed just before 7a. Such advance processing is performed not only in the multi-copy mode but also in the single copy mode using the ADF 50 to improve the copy speed.

On the other hand, the sorter 90 is a non-sort tray 9
This is a well-known type having a 1, 20-stage sort tray 92, and the description thereof is omitted. Next, the ADF 50 will be described in detail. FIG. 2 shows a schematic configuration of the ADF 50. This AD
F50 generally includes a document tray 51, a pickup roller 54, a register roller 58, a transport belt 60,
It comprises a discharge roller 65 and a paper discharge tray 69.
The ADF 50 is installed on the upper surface of the copying machine main body 1 so that the transport belt 60 is located on the platen glass 29, and a hinge fitting (not shown) provided on the back side for an operator to manually set a document. ), The platen glass 29 can be opened. The opening and closing of the ADF 50 is detected by a magnet sensor (not shown), and the operation of the ADF 50 becomes possible only after it is detected that the ADF 50 is correctly closed.

The document tray 51 includes a pair of side regulating plates 5.
2. A tip stopper 53 is provided. The document is placed on the tray 51 with the first page facing upward. The leading end stopper 53 swings downward during sheet feeding and retracts from the regulation position. The pickup roller 54 is attached to the end of a lever 57 rotatable around the support shaft of the normal rotation separating roller 55, and moves down together with the lever 57 to press the upper surface of the document during paper feeding. A reverse separating roller 56 is elastically pressed against the forward separating roller 55 from below.

The register roller 58 is provided with pinch rollers 59a and 59b on the upper and lower sides thereof, and once positions the leading end of the fed document at a nip portion with the pinch roller 59a.
Thereafter, the document is conveyed to the entrance of the platen glass 29 while turning over the document. The transport belt 60 is a platen glass 29
Driven roller 61 and driving roller 62 so as to cover the entire surface of
It is stretched endlessly between and. In order to bring the surface of the belt 60 into contact with the platen glass 29 at a constant pressure, a number of backup rollers 63 are rotatably installed inside the conveyor belt 60. This transport belt 60
Is normally rotated in the direction of arrow c, and the original is
The extremity is adjusted to the exposure reference point O, which is the boundary between the platen glass and the platen glass 29, and stopped. The document feed / transport / stop / discharge processing will be described in detail below.

As a method of stopping the original at the exposure reference point O, there are a scale mode and a pulse control mode. The scale mode is a mode in which the leading end of the scale 28 is made to protrude from the surface of the platen glass 29, and the leading end of the document conveyed by the carrying belt 60 is brought into contact with the scale 28 to forcibly stop. In the pulse control mode, the scale 28 is retracted below the surface of the platen glass 29, the transport amount of the document is counted based on the number of rotations of the drive motor, and the transport is performed so that the leading edge of the document reaches the exposure reference point O. In this mode, the rotation of the belt 60 is stopped.
The ADF 50 employs a pulse control mode.

The reversing / discharging roller 65 has pinch rollers 66a and 66b above and below the reversing / discharging roller 65. The reversing / discharging roller 65 further includes a switching claw 67 for switching a paper passing path for reversing the duplex document around the reversing / discharging roller 65. I have. That is, at the time of document reversal, the switching claw 67 is located away from the surface of the roller 65 as shown in FIG.
The document discharged from above is guided to the outer peripheral surface of the roller 65. The document is turned around the rollers 65 and returned to the platen glass 29 again. At this time, the transport belt 60 is driven to rotate in the direction opposite to the arrow c. On the other hand, when the document is discharged, the switching claw 67 has the tip of the reversing / discharging roller 65.
The document is discharged onto the tray 69 through the discharge roller 68 while being guided by the lower surface of the switching claw 67.

The ADF 50 is driven and controlled by various motors, clutches, and sensors shown in FIGS. That is, the pickup roller 54 is driven by a cam (not shown) driven by the pickup motor M1.
The lowering position is detected by a pickup sensor SE10 which is turned on and off by the notch of the cam. As shown in FIG.
4. The separating rollers 55 and 56 are driven to rotate by a sheet feeding motor M2, and the transport belt 60 is driven by a main motor M3 that can rotate forward and reverse. The reverse / discharge roller 65 and the discharge roller 68 are driven to rotate by a reverse / discharge motor M4. The register roller 58 is driven to rotate by the paper feed motor M2 when the document clutch is turned on when the electromagnetic clutch CL is turned on. When the document is conveyed by the transport belt 60, the register clutch 58 is turned off and driven to rotate by the main motor M3. A one-way clutch OCL is interposed between the main motor M3 and the register roller 58, and the register roller 58 is provided only when the motor M3 is rotating forward.
Is rotated so that no rotational force is transmitted during reverse rotation. An electromagnetic brake BRK1 is provided on the support shaft of the register roller 58, and the drive roller 6
An electromagnetic brake BRK2 is attached to each of the two support shafts to prevent unnecessary rotation of the register roller 58 and the transport belt 60.

Further, the motors M2 and M3 are provided with encoders E2 and E3 for generating rotation pulse signals for detecting the number of rotations, and the pulse signals are input to the microcomputer CPU2. The pulse signal is used for detecting the document length and controlling the document stop position. The ADF 50 is provided with the following document detection sensor. The empty sensor SE11 is installed near the pickup roller 54 and detects the presence or absence of a document on the tray 51. The register sensor SE12 is provided immediately before the register roller 58, and detects a document sent from the tray 51. The width sensor SE13 is installed at a side portion substantially at the same position as the sensor SE12, and has a role of detecting the size of the document in the width direction. The timing sensor SE14 is installed at the entrance of the platen glass 29,
It serves as a reference for document transport control and has a role in detecting the length of the document. The discharge sensor SE15 detects a document discharged from the platen glass 29, and detects the document SE1.
Reference numeral 6 detects a document that has been inverted by the inversion / discharge roller 65.

Here, the document feeding / transporting / discharging processing by the ADF 50 will be described in detail. The document is placed on a tray 51 with the first page facing upward, both sides are regulated by a side regulating plate 52, and the leading end is regulated by a stopper 53. The document is detected by the empty sensor SE11, and a copy process (document feeding operation) is enabled. When the print key by the operator is on, the pickup motor M1 is turned on a predetermined time, the pickup roller 54 is lowered onto the original D _1, and the stopper 53 is retracted [FIGS. 3 (a) Reference.

After a certain time, the paper feed motor M2 is turned on,
As the rollers 54, 55, 56 are driven to rotate,
First original D ₁ is separated into one roller 55, 56
It is sent out from between, and its tip comes into contact with the nip portion between the register roller 58 and the pinch roller 59a. Manuscript D ₁
Is detected by the register sensor SE12, the electromagnetic brake BRK1 is turned on, and the register roller 58 is locked. This register roller 58 by abutment of the leading end of the original D ₁ is to prevent the driven rotation.

[0024] After a certain time from the detection of the leading end of the original by the sensor SE12, the tip end of the original D ₁ forms a slight loop immediately before the register roller 58 [see FIG. 3 (b)], the feed motor M2 is turned off Is done. With this, original D
The skew of ₁ is corrected. Also, the pickup motor M1
Is turned on for a certain period of time, and the pickup roller 54 rises.

Next, the electromagnetic clutch CL is turned on, the electromagnetic brake BRK1 is turned off, and the sheet feeding motor M2 is turned on. At this, the document D ₁ is started the conveyance by the register rollers 58, the same time and on the feed motor M2, and starts counting the number of rotation pulses of the motors M2 emanating from the encoder E2, were counted n1 pulses At this point, the sheet feeding motor M2 is turned off, and deceleration by the regenerative brake is started. When n2 pulses have been counted from the turning off of the sheet feeding motor M2, the electromagnetic brake BRK1 is turned on,
Stop the register roller 58 without fail. Thereafter, the electromagnetic brake BRK1 and the electromagnetic clutch CL are turned off.
At this, it becomes possible to first sheet of first-out feeding of the document D ₁ is completed [FIG. 3 (c) Browse, document D ₁ has a tip at the inlet portion of the platen glass 29, details of the timing sensor SE14 It stands by immediately before (the first reference point P).

[0026] When the above first-out feeding for the original D ₁ as is completed, then the main motor M3 rotates forward on.
At this time, the electromagnetic clutch CL is off, and the register roller 58 is rotationally driven together with the transport belt 60,
Original D ₁ is carried onto the platen glass 29 [Fig. 3
(D)]. During this loading, the timing sensor SE1
4 detects the leading end of the original D ₁ and at the same time, the encoder E
3 starts counting the number of rotation pulses of the main motor M3. The sensor SE14 the document D ₁
Upon detection of the trailing end, the pickup motor M1 is turned on a predetermined time, to press the document D ₂ pickup roller 54 is lowered for the next feed process, waits.

In the present embodiment, when a document is carried into the platen glass 29 from the advance feeding position, the register roller 58 and the transport belt 60 are driven to rotate by the main motor M3. This is because, when both are driven by different motors, it is difficult to synchronize the drive start timing and the document conveyance speed of both, and special control is required for synchronization. If the two driving sources are the same, the difficulty of such synchronization is eliminated.

The number of pulses from the encoder E2 counted during the advance feeding of the original and the timing sensor S
The length of the document in the transport direction is detected by the sum of the number of pulses from encoder E3 counted until E14 is turned off (document trailing edge detection). Further, the width of the document is detected by turning on and off the width sensor SE13, and the size of the document is determined by both of them. The platen glass 29 has an area corresponding to the A3 size. Therefore, when the one-sided original is set on the tray 51 and the length of the original is 216 mm or less, the original is stopped when the leading end thereof reaches the intermediate reference point O ′ (see FIG. 3D), The pre-step mode described below is executed. On the other hand, if the length of the original exceeds 216 mm, the original is conveyed until its leading end reaches the exposure reference point O, and the normal single-sided normal mode is executed.

In the pre-step mode, the following control is performed to stop the original at the pre-step position. First, when n3 pulses from the encoder E3 are counted, the main motor M3 is turned off, and deceleration by regenerative braking is started. The electromagnetic brake BRK2 is turned on when n4 pulses have been counted since the main motor M3 was turned off,
Stop the conveyor belt 60 without fail. The reason why the deceleration is once performed by the regenerative brake and then the electromagnetic brake BRK2 is operated is to prevent a variation in stop timing (conveyance amount) when the brake is suddenly forcibly operated. Another reason is to reduce the expansion and contraction of the transport belt 60 made of an elastic body (based on rubber) to reduce the stopping accuracy of the document.

[0030] As mentioned above, when stopping the rotation of the conveyor belt 60, the leading end of the original D ₁ is designed to reach the intermediate reference point O '. However, the electromagnetic brake BRK2
It takes a short time for the transport belt 60 to actually stop even if the operation is performed, and this causes some variation. That is, strictly speaking, the leading end of the original D ₁ is (not or reaches) slightly gone too far from the intermediate reference point O 'may become. Here, the error of the document D ₁ of the leading edge stopping points with respect to the intermediate reference point O 'and [Delta] x. If not reached, the error is-
Δx.

The error Δx is detected as follows. As described above, when the timing sensor SE14 is turned on (detecting the leading edge of the document), counting of the number of pulses from the encoder E3 of the main motor M3 is started, and the electromagnetic brake BRK2 is operated when n3 + n4 pulses are counted. Are configured to stop at the intermediate reference point O ′. However, the rotation of the main motor M3 is stopped when the number of pulses n3 + n4 + x slightly increased / decreased from the n3 + n4 pulses due to the response characteristics of the electromagnetic brake BRK2, fluctuations in the braking performance, and the like. In this embodiment, when the rotation of the main motor M3 stops, this error is detected as an x pulse and stored in the CPU 2.

Next, the second original D ₂ on the tray 51 to the first-out feeding position-feed [Fig 4 (e) Reference. Although first-out feeding process is basically the same as described above, since the document D ₁ of the first sheet has an error of x pulses the intermediate reference point O ', the paper feed motor M2 after being resist Is turned on, the sheet feeding motor M2 is turned off when n1 + x pulses are counted. This in, so that the first-out feeding position of the next document D ₂ is corrected according to the error x pulse between the intermediate reference point O 'of the previous document D _1.

Next, conveys a document D ₁ from the pre-step position to the exposure position where the front end is positioned in the exposure reference point O.
First, the main motor M3 is turned on. With this, original D
_1, the transport of D ₂ is resumed, at the same time starts counting the number of pulses from the encoder E3 and on the motor M3. In this embodiment, the leading edge of the document is set so as to reach the exposure reference point O from the intermediate reference point O 'when the pulse from the encoder E3 is counted by n5 + n4 + a after the main motor M3 is turned on. However, as described above, since the leading end of the original D ₁ stopped at the pre-step position occurs an error of x pulses the intermediate reference point O ', at the time the pulse is n5-x pulse count from the encoder E3 The main motor M3 is turned off, and deceleration by regenerative braking is started. Further, when the n4 pulses are counted, the electromagnetic brake BRK2 is turned on, and the transport belt 60 is stopped. This in document D ₁ is its front end exposed reference point O
Is stopped at the exposure position located at. The leading edge of the _second original D2 reaches the intermediate reference point O 'and stops [FIG.
(F)].

By the way, since the original D ₂ is that the first-out feeding position is previously corrected by x pulses, without being influenced by the error x pulse between the first sheet of the intermediate reference point O of the document D ₁ ' Is conveyed / stopped to the pre-step position. However, in practice, as described in the transfer / stop of the document D _1,
When the rotation of the transport belt 60 stops after the operation of the electromagnetic brake BRK2, there is a slight variation, and the document D ₂
, An error is generated between the reference point and the intermediate reference point O ′. That is to convey at the same time conveys a document D ₁ from the pre-step position to the exposure position, the document D ₂ from first-out feeding position to the pre-step position. For the conveyance of the original D _2, as described above, it counts the number of pulses from the encoder E3 concurrently on the main motor M3, alternatively, the main from the on timing sensor SE14 (the detection of the leading end of the original D ₂₎ It detects how much the number of pulses counted until the motor M3 is turned off is shifted from n3 + n4 + a. Without this shift, the leading end of the original D ₂ will be stopped correctly in the intermediate reference point O '. Here, the error of the document D ₂ with respect to the intermediate reference point O 'and y pulse.

On the other hand, when the trailing edge of the document D ₂ is detected by the register sensor SE12, the pickup motor M
1 for a predetermined time on to be pressed against the pickup roller 54 on the third original D _3. When the leading end of the original D ₂ reaches the intermediate reference point O ', turns on the sheet feed motor M2 in a state of turning off the electromagnetic clutch CL. This by the pickup roller 54 is driven separating rollers 55 and 56 rotate, the document D ₃ are fed from the tray 51, the leading end once waits in the nip between the register roller 58 and the pinch roller 59a [FIG 4 (f )reference]. Here, image exposure is performed on the _first document D1 by the optical system 20. During this image exposure, the paper feed motor M2 is turned on to feed the _third original D3 in advance (see FIG. 4 (g)). In this advance feeding process, the leading edge of the _second document D2 has an error of y pulse with respect to the intermediate reference point O ′.
The motor M2 is turned off when n1 + y pulses are counted after the paper feeding motor M2 is turned on. Thus, the advance feeding position of the _third original D3 has been corrected in accordance with the error y pulse of the _second original D2.

Next, the main motor M3 and the discharge motor M
Turn on 4. At this, the first document D ₁ tray 6
Is discharged onto the 9, second original D ₂ is transported to the exposure position, third original D ₃ is conveyed to the pre-step position [Figure 4 (h) Reference. Specifically, the counting of the number of pulses from the encoder E3 is started simultaneously with the turning on of the main motor M3, and the main motor M3 is turned off when n5-y pulses are counted, and deceleration by regenerative braking is started. Further, when the n4 pulses are counted, the electromagnetic brake BRK2 is turned on, and the transport belt 60 is stopped.
Since the document D ₃ is being corrected its first-out feeding position by y pulses, it is not affected by the error y pulses at pre-step position of the original D ₂ of the second sheet, and stops at the pre-step position . However, the document D ₃ produces a new error between the tip of the intermediate reference point O '. This error is referred to as a z pulse.

On the other hand, when the trailing edge of the document D ₃ is detected by the register sensor SE12, the same manner, it presses the original D ₄ of the fourth sheet in the pickup roller 54, the document D ₃ tips intermediate reference point O Upon reaching the 'to turn on the feed motor M2, the document D ₄ whose tip once wait for the nip between the register roller 58 and the pinch roller 59a [FIG 4 (h) reference. Here, image exposure is performed on the _second document D2, and the paper feed motor M2 is turned on to feed the _fourth document D4 in advance (see FIG. 5 (i)). In this first-out feeding process, third original D ₃ is to have an error of z pulse in the pre-step position, and turns off the motor M2 at the time of counting the n1 + z pulses the sheet feeding motor M2 from ON. This means that the advance feeding position of the _fourth document D4 has been corrected in accordance with the error z pulse of the _third document D3.

Hereinafter, the above-described operation is repeatedly executed.
With second original D ₂ is discharged onto the tray 69,
Third original D ₃ is transported to the exposure position, 4-sheet document D ₄ is conveyed to the pre-step position [Figure 5 (j) Reference. Here document conveyance amount in is n5 + n4-z, the document D ₄ without being affected by the 3rd error z pulses of the document D _3, and, previous document D _1, D ₂ of the error x pulse , Y pulse stops and stops at the pre-step position. When the image exposure for the original D ₃ is completed, FIG. 5 where the document D ₃ together with is discharged onto the tray 69, 4-sheet document D ₄ is conveyed / stop to the exposure position
(K)]. Further, when the image exposure is completed for the original D _4, so that the document D ₄ is discharged onto the tray 69 [FIG 5 (l) Reference.

On the other hand, if the length of the original exceeds 216 mm, the single-sided normal mode is executed. In this case, when the trailing end of the first document is detected by the register sensor SE12, the pickup roller 54 is lowered. After the leading edge of the first document is detected by the timing sensor SE14, the pulse from the encoder E3 of the main motor M3 changes to n.
The motor M3 is turned off at the time when the count has been counted 7, and deceleration by regenerative braking is started. Further, when n4 pulses are counted from the turning off of the motor M3, the electromagnetic brake BR
K2 is turned on, and the transport belt 60 is stopped. As a result, the first document is conveyed / stopped to the exposure position where the leading end is located at the exposure reference point O. Here, image exposure is performed on the first document, and the second document is fed in advance. That is, after a certain period of time after the main motor M3 is completely stopped, the sheet feeding motor M2 is turned on to separate the second document from other documents, and the leading end of the document is nipped between the register roller 58 and the pinch roller 59a. To correct the skew. After that, while turning on the electromagnetic clutch CL,
The sheet feeding motor M2 is turned on again, and the register roller 58 is rotated. As a result, the conveyance of the second original to the advance sheet feeding position is started, and the motor M2 is turned off when the pulse of the encoder E2, which has started counting simultaneously with the turning on of the sheet feeding motor M2, is counted as n1. Start deceleration by the brake. When the feeding motor M2 is turned off and the pulse from the encoder E2 is counted n2, the electromagnetic brake BRK1 is turned on to complete the advance feeding process of the second original.

When the image exposure for the first document is completed, the main motor M3 and the discharge motor M4 are turned on, the first document is discharged onto the tray 69, and the second document is advanced to the first sheet feeding position. To the exposure position. Thereafter, the above-described control is repeated until the final document is discharged onto the tray 69. Next, the control of the ADF 50 will be described in detail.

The control is performed by controlling C for controlling the copying machine body 1.
PU1 (see FIG. 7) and C for controlling the ADF 50
This is executed by PU2 (see FIG. 8). CPU1,2
Exchange information at the required timing. By the way, in the description of the control procedure, on-edge is a sensor,
A flag, a signal, or the like means that the state is switched from the off state to the on state, and an off edge means that these are switched from the on state to the off state.

FIG. 9 shows a main routine of the CPU 1 for controlling the main body 1 of the copying machine. When the power is turned on and the CPU 1 is reset and the program starts, in step S1, the RAM is cleared, various registers are reset, and initial settings for setting various devices to the initial mode are performed. Subsequently, the internal timer is started in step S2. The internal timer determines the time required for one of the main routines, and its value is set in step S1. Further, this internal timer is a reference for counting of various timers appearing in each subroutine.

Next, the subroutines of steps S3 and S4 are sequentially called, necessary processing is performed, and in step S5, the process returns to step S2 after the internal timer is terminated. Step S3 is a subroutine for executing a copy process. Step S4 carries out other processing, for example, control of the toner fixing device 40, detection of a paper jam, and the like.

The CPU 1 is connected to the CPU 2 via a serial communication line, and transmission and reception are performed in step S6 by interrupt processing. Next, a control procedure of the CPU 2 for controlling the ADF 50 will be described. Before that, a counter, a pulse, and a timer used in the control there will be described. Counter PCNTM2: Encoder E of paper feed motor M2
It is incremented by one pulse output from 2.

Counter PCNTM3a: Main motor M
3 is incremented by one pulse output from the encoder E3. Counter PCNTM3b: Similarly, is incremented by one pulse output from the encoder E3 of the main motor M3. Counter PPSE14: Stores the number of pulses until the leading edge of the document reaches the detection point of timing sensor SE14 from advance reference point P.

Counter PSIZE: Stores the number of pulses corresponding to the length of the document. Counter POVER: Stores the number of pulses when the leading edge of the document set at the pre-step position exceeds the intermediate reference point O '. Counter LST: Displays the number of documents located inside the ADF 50. When "0", the original is in the advance feeding position,
Indicating that it is in the pre-step position and the exposure position,
When it is "1", it indicates that the document is at the pre-step position and the exposure position (that is, the last two sheets),
In the case of "2", the document is only at the exposure position (that is,
(Last one).

Pulse n1: feed motor M during advance feed
Number of pulses from turning on 2 to turning off. Pulse n2: the number of pulses from turning off the paper feeding motor M2 to turning on the electromagnetic brake BRK1 during advance feeding. Pulse n3: The first document is the timing sensor SE14
The number of pulses from the detection in step (1) until the main motor M3 is turned off to stop at the pre-step position.

Pulse n4: The number of pulses from turning off the main motor M3 to turning on the electromagnetic brake BRK2 to stop the original at the pre-step position and / or the exposure position. Pulse n5: the number of pulses from turning on the main motor M3 to turning it off in order to convey the document from the pre-step position to the exposure position.

Pulse n7: In the single-sided normal mode, the number of pulses from when a document is detected by the timing sensor SE14 to when the main motor M3 is turned off to stop at the exposure position. Pulse nL: the number of pulses when the length of the document corresponds to 216 mm. It is used to determine whether to execute the pre-step mode by comparing the number of pulses stored in the counter PSIZE.

NSE14O ': The number of pulses corresponding to the distance that the document is transported from the detection point of the timing sensor SE14 to the intermediate reference point O'. Timer T101 is set to the time until the pickup roller 54 completely falls from the home position. Timer T102 is set to the time from when the leading edge of the document sent out from the tray 51 is detected by the register sensor SE12 to when it comes into contact with the nip portion between the register roller 58 and the pinch roller 59a and the skew is corrected. .

Timer T103: The timer T103 is set to the time from when the paper feeding motor M2 is turned off until it stops. Timer T104: The time is set from when the electromagnetic brake BRK1 is turned on to when the register roller 58 stops. Timer T105 is set to the time from when the electromagnetic brake BRK1 is turned off to when the constraint on the register roller 58 is released.

Timer T201 is set to the time from when the electromagnetic brake BRK2 is turned on to when the transport belt 60 stops. Timer T202 is set to the time from when the electromagnetic brake BRK2 is turned off to when the restraint on the transport belt 60 is released. Timer T301: Set to the time to delay the start of document ejection.

Timer T302 is set to the time from when the trailing end of the document is detected by the discharge sensor SE15 to when the document is discharged onto the tray 69. Timer T303: Set to the time from when the discharge motor M4 turns off to when it stops. FIG. 10 shows a main routine of the CPU 2 for controlling the ADF 50.

When the power is turned on and the CPU 2 is reset and the program starts, in step S11, the RAM is cleared, various registers are reset, and initial settings for setting various devices to the initial mode are performed. Subsequently, the internal timer is started in step S12. The internal timer determines the time required for one of the main routines, and its value is set in step S11. The internal timer also serves as a reference for counting various timers appearing in a subroutine described below.

Next, the subroutines of steps S13 to S15 are sequentially called, necessary processing is performed, and step S13 is executed.
At 16, the process returns to step S12 after the end of the internal timer. Step S13 is a subroutine for exchanging the original on the platen glass 29. Step S14 is a subroutine for counting various timers. Step S15 performs other processing, that is, A / D conversion, input processing, output processing, paper jam detection, and the like.

The interrupt processing for the CPU 2 includes various interrupt processing such as control of the main motor M3 in step S17, and data transmission processing and data reception processing with the CPU 1 in steps S21 and S22 shown in FIG. Is performed as appropriate regardless of the processing of. FIG. 12 shows an initialization subroutine executed in step S11.

In step S31, each data in the RAM is
Clear each counter. In step S32, the timer T
101 to T106, T201, T202, T301 to T
Reset 303. In step S33, each flag described below is reset. In step S34, the motors M1, M2, M3, and M4, the electromagnetic clutch CL, and the electromagnetic brakes BRK1 and BRK2 are turned off. Step S
At 35, the internal timer is set to a predetermined value. In step S36, the paper feed status K is set to "1". In step S37, other initial settings are processed.

FIG. 13 shows a document exchange subroutine executed in step S13. In this subroutine, MODE is checked in step S40, and the following processing is performed based on the value. MODE is initially reset to "0". At this time, a start check is processed in step S41. In the subroutine of step S41, MODE is set to a predetermined value according to the document conveyance mode selected by the operator. (See FIG. 14, steps S68, S69, S70).

When MODE is "1", the mode is a one-sided document transport mode, and in step S42, the document is transported from the tray 51 to the advance feeding position. Subsequently, in step S43, pre-step feeding for transporting the one-sided document to the pre-step position and the exposure position, or single-sided normal feeding for transporting the one-sided document directly to the exposure position is performed. Further, in step S44, a process of discharging the document from the exposure position to the tray 69 is performed.

If MODE is "2", the mode is a double-sided original transport mode, in which sheet feeding is performed in step S45, and setting of the double-sided original to the exposure position is performed in step S46.
In step S47, the sheet is discharged. Details of these processes are omitted. When MODE is "3", it is a 2-in-1 mode. 2-in-1 mode means that two originals are
This is a copy mode in which two original images are formed on a single copy sheet by arranging them successively on the platen glass 29 as a set. Here, sheet feeding is performed in step S48, setting of two documents on the platen glass 29 is performed in step S49, and sheet discharging is performed in step S50. Details of these processes are omitted.

FIG. 14 shows a start check subroutine executed in step S41. This subroutine is processed when MODE is "0", that is, when the ADF 50 is in a standby state. First, in step S61, it is determined whether or not the empty sensor SE11 is on. If it is not turned on, the document has not yet been set on the tray 51, and this subroutine is immediately terminated.
When the sensor SE11 is turned on (when a document is set on the tray 51), it is determined in a step S62 whether or not the flag DCHG is "1". The flag DCHG is a command for requesting the exchange of a document when it is “1”.
Sent from This flag DCHG is set to “1” when the print key is turned on and the image scanning for the number of copies is completed.
Is set to Therefore, if the flag DCHG is "1", the flag DCHG is reset to "0" in step S63, and the sheet feeding status K is set to "3" in step S64.
And return. The status K is used in the paper feeding subroutine, and the paper feeding process is started when it is set to “3”.

On the other hand, when the sensor SE11 is on and the flag D
If CHG is “0”, it is determined in step S65 whether or not the status K is “2”, and in step S66, whether or not the status K is “20”. If the status K is “2”, that is, if the return of the pickup roller 54 to the home position has been completed, as described below,
If the value is other than "20", the subroutine is terminated. If the status K is "20", that is, as described below, after the first original has been fed in advance, the original mode is checked in step S67.
If in the single-sided mode, MODE is set to "1" in step S68.
And if the mode is the duplex mode, the MO is set in step S69.
DE is set to "2", and if it is a 2-in-1 mode, MODE is set to "3" in step S70. continue,
In step S71, the set status S used when the original is set on the platen glass 29 is set to "1", and this subroutine ends.

FIGS. 15 to 19 show a subroutine for paper feed executed in step S42. In this subroutine, the paper feed status K is checked in step S80, and the following processing is performed based on the values "0" to "11" and "20". The status K is initially reset to "0", and no processing is performed at this time.

When the status K is "1" (see step S36 of the initial setting), the pickup roller 54 is returned to the upper home position. That is, step S
At 81, the pickup motor M1 is turned on, and step S8
When the off edge of the pickup sensor SE10 is confirmed in step 2, the motor M1 is turned off in step S83 assuming that the pickup sensor SE10 has returned to the home position, and the status K is set to "2" in step S84.

When the status K is "2", no processing is performed and the process stands by. When the status K is "3" (see step S64 for start check, steps S217, S269, and S337 for single-sided document setting), document feeding is started. First, in step S91, the pickup motor M1 is turned on. Here, when the pickup roller 54 descends and the on-edge of the sensor SE10 is confirmed in step S92, the motor M1 is turned off in step S93 and the timer T101 is set in step S94 because the pickup roller 54 has descended to a predetermined position. , The status K is set to "4" in step S95.

When the status K is "4", in step S101, the process waits for the end of the timer T101, that is, waits for the pickup roller 54 to completely stop descending and press the document, and then in step S102, feeds the document. The paper motor M2 is turned on, and the status K is set to "5" in step S103. As a result, the pickup roller 54 and the separating rollers 55 and 56 rotate, and the original is sent out from the tray 51, separated into one uppermost layer, and the register roller 5 is separated.
Go to 8.

If the status K is "5", it is determined in step S105 whether or not the register sensor SE12 is on-edge.
If detected at E12), the timer T
102 and set the electromagnetic brake B in step S107.
Turn on RK1. Thus, the register roller 58 is locked. Subsequently, the status K is set to "6" in step S108.

When the status K is "6", the process waits for the end of the timer T102 in step S111, and then proceeds to step S111.
At 112, the sheet feeding motor M2 is turned off. Here, the leading end of the document comes into contact with the nip portion between the register roller 58 and the pinch roller 59a to form a predetermined amount of loop, and skew is corrected. Subsequently, the timer T103 is set in step S113, and the status K is set to "7" in step S114.

When the status K is "7", the electromagnetic clutch CL is turned on in step S121, and the process proceeds to step S12.
After waiting for the end of the timer T103 at 2, the electromagnetic brake BRK1 is turned off at step S123. Thus, the register roller 58 can be driven to rotate by the sheet feeding motor M2. Subsequently, at step S124, the counter PCNTM2
Is reset to "0", the sheet feeding motor M2 is turned on in step S125, the pickup motor M1 is turned on in step S126, and the status K is turned on in step S127.
Is set to “8”. When the sheet feeding motor M2 is turned on, the document is started to be conveyed by the register roller 58, and the number of pulses from the encoder E2 is set to PCNTM2.
Starts counting. Also, the pickup motor M1
Is turned on, the pickup roller 54 starts returning upward.

When the status K is "8", the count value of PCNTM2 is set to n1 + POVE in step S131.
It is determined whether it is R or not. Normally, PCNTM2 is n1 + PO
Before counting VER (N in step S131)
O), the sensor SE10 is determined to be off-edge in step S134, and the pickup motor M is determined in step S135.
Turn 1 off. Thus, the pickup roller 54 has returned to the home position. When PCNTM2 counts n1 + POVER (however, POVER
Is initially reset to "0"),
In step S132, the paper feeding motor M2 is turned off, and in step S133, the status K is set to "9". Here, the sheet feeding motor M2 starts to decelerate due to the action of the regenerative brake.

If the status K is "9", the count value of PCNTM2 is incremented by n1 + POVE in step S141.
It is determined whether or not R + n2. When n1 + POVER + n2 is counted, the electromagnetic brake BR is determined in step S142.
K1 is turned on, the timer T104 is set in step S143, and the status K is set to "10" in step S144. Thus, the rotation of the register roller 58 is stopped, and the advance feeding of the document is completed. POVER is 1
It is reset to "0" when feeding the first document.
The first document is stopped when the leading edge reaches the advance reference point P at n1 + n2 + α (α is an error). For the second and subsequent documents, the error of the leading end of the preceding document with respect to the intermediate reference point O 'is stored in POVER as the pulse number (see steps S214 and S264), so that the first sheet feeding position is corrected. . Also, by turning on the regenerative brake before the electromagnetic brake BRK1 is turned on to decelerate the sheet feeding motor M2, variations in the amount of rotation due to the inertia of the motor M2 after the electromagnetic brake BRK1 is turned on are suppressed, and the error α can do.

When the status K is "10", after the end of the timer T104 is confirmed in step S151, that is, after the register roller 58 is completely stopped, the count value of PCNTM2 is stored in PSIZE in step S152. Subsequently, at step S153, the electromagnetic clutch CL is turned off, and at step S154, the electromagnetic brake BRK is turned off.
Turn 1 off. As a result, the connection of the register roller 58 with the sheet feeding motor M2 is released, and the register roller 58 becomes free.
Further, the timer T105 is set in step S155, and the status K is set to "11" in step S156.

When the status K is "11", the end of the timer T105 is confirmed in step S161, and the status K is set to "20" in step S162.
When the status K is "20", the advance feeding of the document has been completed, and the process stands by without any processing. FIG.
30 show a subroutine for setting a one-sided document at a predetermined position on the platen glass 29, which is executed in step S43.

In this subroutine, the set status S is checked in step S170, and its value "0" to "2" is checked.
The following processing is performed based on "2." If the status S is “0” (at the time of initialization), MOD is set in step S171.
E is reset to "0", and the paper feed status K is set to "2" in step S172.

If the status S is "1" (feed completed, see steps S66 and S71), step S175
Turns on the main motor M3, and sets the status S to "2" in step S176. Here, the register roller 58 and the transport belt 60 are driven to rotate, and the first-fed original is started to be conveyed onto the platen glass 29.

When the status S is "2", if the on-edge of the timing sensor SE14 is confirmed in step S181, that is, if the leading edge of the document is detected by the sensor SE14, the encoder E3 of the main motor M3 is detected in step S182. PC that counts the number of pulses output from
The NTM 3a is reset to "0" and the counting is started. Subsequently, the status S is set to "3" in step S183.

When the status S is "3", if the off-edge of the register sensor SE12 is confirmed in step S191, that is, if the rear end of the document is detected by the sensor SE12, the count value of PSIZE (step S192) is reached. Step S152) and PCNTM3 at that time
The count value of “a” is added and stored in PSIZE. This count value corresponds to the length of the document. Subsequently, in step S193, PSIZE is compared with the pulse nL. nL
Is the number of pulses corresponding to a document length of 216 mm,
If PSIZE <nL, the status S is set to "4" in step S194, and the pre-step mode is executed. If PSIZE ≧ nL, the status S is set to “17” in step S195, and the one-sided normal mode is executed.

When the status S is "4", if it is confirmed in step S201 that the count value of the PCNTM 3a has reached n3, the main motor M3 is turned off in step S202 and the status S is set to "5" in step S203. set. Here, the main motor M3 starts decelerating by the action of the regenerative brake. When the status S is "5", when it is confirmed in step S205 that the count value of the PCNTM3a has reached n3 + n4,
In step S206, the electromagnetic brake BRK2 is turned on.
Subsequently, the timer T201 is set in step S207, and the status S is set to "6" in step S208. Thus, the document is set at the pre-step position. By turning on the regenerative brake before turning on the electromagnetic brake BRK2 to decelerate the main motor M3,
The variation in the rotation amount due to the inertia of the motor M3 after the electromagnetic brake BRK2 is turned on is suppressed, and the stop position accuracy of the document, that is,
An error with respect to the intermediate reference point O ′ at the leading end of the document can be reduced. Furthermore, the amount of contraction of the transport belt 60 that occurs after the electromagnetic brake BRK2 is turned on can be reduced, and the displacement of the document due to the contraction of the belt can be eliminated.

When the status S is "6", the timer T201 is confirmed to have ended in step S211.
After the transport belt 60 is completely stopped, the process proceeds to step S212.
To turn off the electromagnetic brake BRK2, and set the timer T202 in step S213. Subsequently, step S21
In step 4, the count value (number of pulses) of PCNTM3a is used as nS
The value obtained by subtracting E14O 'is stored in POVER.
PCNTM3a is a count value (the number of pulses) corresponding to the distance that the document is actually conveyed from the detection point of the timing sensor SE14 to the pre-step position.
O ′ is the number of pulses corresponding to the distance conveyed from the detection point of the timing sensor SE14 to the intermediate reference point O ′.
Accordingly, the POVER stored in step S214 corresponds to an error with respect to the intermediate reference point O 'of the document stopped at the pre-step position, and this POVER is used in steps S131 and S141 in the advance feeding process, so that the advance feeding is performed. The advance feeding position of the original on paper is corrected according to the stop position error of the original.

Next, in step S215, it is determined whether the empty sensor SE11 is on or off. If the sensor SE11 is on, the next document is present on the tray 51, so the paper feed status K is set to "3" in step S217, and the status S is set to "7" in step S218. If the sensor SE11 is off, all the originals on the tray 51 have been fed, and the LST
Is set to “1”, and in step S218, the status S
Is set to “7”.

If the status S is "7", the timer T202 is confirmed to have ended in step S221, that is,
If the main motor M3 becomes completely free when the electromagnetic brake BRK2 is turned off, the status S is set to "8" in step S222. When the status S is "8",
In step S225, it is determined whether the paper feeding status K is “20”. If the status K is set to "20", the advance feeding of the next document has been completed, so that the PCNTM 3b is reset to "0" in step S226 and the counting thereof is started. Subsequently, in a step S227, it is determined whether or not the flag DSET is “1”.
The flag DSET indicates that the document is set at the exposure position (see step S266). Flag DSE
If T is “0”, the process moves to step S230, and “1”
If so, the flag DSET is reset to "0" in step S228, the discharge status H used to discharge the document to the tray 69 is set to "1" in step S229, and the process proceeds to step S230.

In step S230, the main motor M3 is turned on. Then, in step S231, the value of the counter LST is checked. LST indicates the number of documents in the ADF 50. If "0", the document is located at the advance feeding position. In this case, the status S is set to "9" in step S232. If the LST is not "0", there is no original at the advance feeding position, and in this case, the status S is set to "10" in step S233.

When the status S is "9", when the on-edge of the timing sensor SE14 is confirmed in step S235, that is, when the leading edge of the document is detected by the sensor SE14, the PCNTM 3a is set to "0" in step S236.
And the counting is started. Here, the measurement of the transport amount of the next document to the pre-step position is started. Subsequently, in step S237, the status S
Is set to “10”.

If the status S is "10", the count value of the PCNTM3b is set to n5-PO in step S241.
Upon confirming that the VER has been reached, step S242 is performed.
To turn off the main motor M3, and set the status S to "11" in step S243. Here, the main motor M3 starts decelerating by the action of the regenerative brake. When the status S is "11", P is set in step S251.
When it is confirmed that the count value of the CNTM3b has reached n5-POVER + n4, the value of the counter LST is checked in step S252. If the LST is other than “2”, that is, if at least two documents exist on the platen glass 29 before the document transport here, the electromagnetic brake BRK2 is turned on in step S253, and in step S254 The timer T201 is set. If the LST is “2”, only the final document was present at the exposure position before the document was conveyed here, and the electromagnetic brake BRK2
Without turning on (for discharging the original), step S2
At 54, the timer T201 is set. Subsequently, the status S is set to "12" in step S255.

When the status S is "12", after the end of the timer T201 is confirmed in step S261, that is, after the transport belt 60 is completely stopped, step S2 is executed.
At 62, the electromagnetic brake BRK2 is turned off, and step S26 is performed.
At 3, the timer T202 is set. Then, step S
In step 264, a value obtained by subtracting nSE14O 'from the count value (number of pulses) of PCNTM3a is stored in POVER. Here, the memory value of POVER is determined in step S
As described at 214, this corresponds to the stop position error of the document conveyed to the pre-step position with respect to the intermediate reference point O '. In this embodiment, a stop position error with respect to the intermediate reference point O 'is always detected, and if there is a next document in accordance with the value, it is used for correcting the advance feeding position.

Next, at step S265, the counter LST
Is determined to be "2", that is, if only the last original is present at the exposure position, the process proceeds to step S273.
Resets the LST to "0" and sets the status S to "22" in step S274. If the LST is other than “2”, at least two originals
If it is present on the step S9, the flag DSET is set to "1" in a step S266. The flag DSET indicates that the document has been set at the exposure position.

Next, at step S267, the counter LST
Check the value of. If "1", the document exists only at the exposure position and the pre-step position before that, and since the document is currently set only at the exposure position, the LST is incremented to "2" at step S270. The status S is set to "13" in step S272. On the other hand, if the LST is other than "1", that is, if it is "0" (see step S265), since the document has been set at the exposure position, pre-step position and advance feeding position before that, the empty sensor is set at step S268. It is determined whether or not SE11 is on. If the sensor SE11 is ON and the original remains on the tray 51, the process proceeds to step S2.
At 69, the paper feed status K is set to "3", and at step S272, the status S is set to "13". If the sensor SE11 is off and no original remains on the tray 51, since the original is currently set only at the exposure position and the pre-step position, the LST is set to "1" in step S271, and the status S is set in step S272. Is set to “13”.

When the status S is "13", it is confirmed in step S275 that the timer T202 has expired, that is, if the main motor M3 is completely free when the electromagnetic brake BRK2 is turned off in step S262, the step S275 is executed. In step S276, the status S is set to "14".
When the status S is "14", the flag DCHG is "1" in step S281 (request for document exchange), and the paper feed status K is "20" in step S282.
(Completion of advance feeding) and step S28
After confirming that the paper ejection status H is "6" (completion of paper ejection) in step 3, the flag DCHG is determined in step S284.
Is reset to "0", and the status S is set to "8" in step S285. Thus, the document exchange process is restarted.

When the status S is "15" (when executing the one-sided normal mode, see step S355), it is determined in step S291 whether or not the flag DSET is "1". If “1”, that is, if the document is set at the exposure position, the flag DS is set in step S292.
ET is reset to "0", the discharge status H is set to "1" in step S293, and the main motor M3 is turned on in step S294. Thus, the discharge of the document from the exposure position is started. Subsequently, the value of the counter LST is checked in step S295. If the LST is "0", the next original has been fed in advance, so the status S is set to "16" in step S296. L
If ST is not "0", that is, if there is no original at the advance feeding position, in step S297, PCNTM3a is reset to "0" and the counting is started. Subsequently, in step S298, the status S is set to "1".
7 ”.

When the status S is "16", when the on-edge of the timing sensor SE14 is confirmed in step S301, that is, when the leading edge of the document is detected by the sensor SE14, the PCNTM 3a is set to "0" in step S302. Reset and start counting. Subsequently, in step S303, the status S is set to "1".
7 ”.

When the status S is "17", when it is confirmed in step S311 that the count value of the PCNTM 3a has reached n7, the main motor M3 is turned off in step S312, and the status S is set to "18" in step S313. set. Here, the main motor M3 starts decelerating by the action of the regenerative brake. Status S
Is "18", PCNTM3 is set in step S321.
After confirming that the count value of “a” has reached n7 + n4, the value of the counter LST is checked in step S322. If LST is not "1", that is, since the next original is at the advance feeding position, the electromagnetic brake BRK2 is turned on in step S323, and the process proceeds to step S324. If LST is "1", that is, since there is no original at the advance sheet feeding position and only the last original has been set at the exposure position, the timer T201 is reset at step S324 while the electromagnetic brake BRK2 is kept off. Set
In step S325, the status S is set to "19".

When the status S is "19", after the end of the timer T201 is confirmed in step S331, that is, after the conveyance belt 60 is completely stopped, step S3 is executed.
At step S32, the electromagnetic brake BRK2 is turned off, and at step S33
At 3, the timer T202 is set. Then, step S
At 334, the value of the counter LST is checked. If LST is not "1", that is, if the next original has been set at the advance feeding position, the next original has been set at the exposure position, and the flag DSET is set to "1" at step S335. . Further, in step S336, it is determined whether or not the empty sensor SE11 is on. If the sensor SE11 is ON and the document remains on the tray 51, the paper feed status K is set to "3" in step S337, and the status S is set to "20" in step S339. If the sensor SE11 is off and no document remains on the tray 51, the document is currently set only at the exposure position, so the LST is set to "1" in step S338, and the status S is set to "20" in step S339. Set to. On the other hand, if LST is “1” (NO in step S334), that is, since the last original has been discharged,
In step S340, LST is reset to "0", and in step S341, status S is set to "22".

If the status S is "20", the end of the timer T202 is confirmed in step S345, that is, if the main motor M3 is completely free, the status S is set to "21" in step S346. . When the status S is "21", the flag DCHG is "1" in step S351 (document replacement request), and in step S352, the paper feeding status K is "20" (completion of advance feeding). After confirming that the discharge status H is "6" (discharge completion) in step S353, the flag DCHG is reset to "0" in step S354, and the status S is set to "1" in step S355.
5 ”. Thus, the document exchange process is restarted.

When the status S is "22", after confirming the end of the timer T202 in step S361, that is, when it is confirmed that the main motor M3 is completely free, the status S is changed in step S362. "0"
And the subroutine ends. FIG.
FIG. 33 shows a subroutine for processing the discharge of a document, which is executed in step S44.

Here, the paper discharge status H is checked in step S370, and the following processing is performed based on the values "0" to "6". When the status H is "0", it is an initial state and does not perform any processing. Status H is "1"
In the case of (1), when the document begins to be discharged from the exposure position (see steps S229 and S293), the timer T301 is set in step S371, and the status H is set to "2" in step S372. The timer T301 delays the driving of the discharge motor M4 until immediately before the leading edge of the document reaches the reverse / discharge roller 65.

When the status H is "2", when the end of the timer T301 is confirmed in step S375, the discharge motor M4 is turned on in step S376, and the process proceeds to step S3.
At 77, the status H is set to "3". Here, the reversing / discharge roller 65 and the discharge roller 68 start rotating, and the document starts to be discharged onto the tray 69. When the status H is "3", the discharge sensor S is determined in step S381.
After confirming the off-edge of E15, that is, when the rear end of the document is detected by the sensor SE15, the timer T302 is set in step S382, and the status H is set to "4" in step S383.

When the status H is "4", the end of the timer T302 is confirmed in step S385, that is,
After the document is completely discharged onto the tray 69, the process proceeds to step S
At 386, the discharge motor M4 is turned off. Further, in step S387, the timer T303 is set, and in step S38
At step 8, the status H is set to "5". Status H
Is "5", the timer T303 is determined in step S391.
Is completed, that is, when the discharge motor M4 is completely stopped, the status H is set to "6" in step S392.

When the status H is "6", no processing is performed and the process stands by. As described above, in the above-described embodiment, the register roller 58 is driven to rotate by the feed motor M2 at the time of advance feeding, and the register roller 58 is driven to rotate together with the transport belt 60 by the main motor M3 at the time of document replacement. Then, the stop position error at the pre-step position is determined by the feed motor M2 during the advance feeding of the next original.
Is controlled to correct the advance feeding position. As a result, it is possible to prevent an error from the intermediate reference point O 'at the pre-step position of the previous document from affecting the accuracy of stopping the next document at the pre-step position.

On the other hand, if a configuration in which the register roller 58 is driven completely independently of the conveyor belt 60 is employed, the same effect can be achieved by other control methods. That is,
As shown in FIG. 34, the main motor M3
0 is driven, and the register roller 58 is driven only by the sheet feeding motor M2 via the electromagnetic clutch CL. Of course, the document conveying speeds of the register roller 58 and the conveying belt 60 are the same.

In such a configuration, at the time of advance feeding, the original is stopped so that its leading end is always located at the advance reference point P. Then, at the time of document exchange, the timing at which the next document is sent out from the advance sheet feeding position is changed in accordance with the stop error Δx of the previous document at the pre-step position. For example, if the leading end of the previous document has passed the intermediate reference point O 'too much, the paper feeding motor M2 is turned on, and the main motor M3 is turned on when the pulse from the encoder E2 is output by an amount corresponding to the error + Δx. I do. If the leading end of the previous document has not reached the intermediate reference point O ', the main motor M3
Is turned on, and when the pulse from the encoder E3 is output by an amount corresponding to the error −Δx, the sheet feeding motor M2 is turned on. That is, when the error is positive, the transport timing of the original at the advance feeding position is advanced according to the error, and when the error is negative, the transport timing is delayed according to the error. However, in such a control method, it is necessary to consider the rising characteristics of the sheet feeding motor M2 and the main motor M3 when setting the advance reference point P.

On the other hand, in the driving system shown in FIG. 34, if a stepping motor is used as the sheet feeding motor M2, the same effect can be achieved by controlling the number of driving pulses during the start-up time of the motor M2. Specifically, it is assumed that the leading end of the document is stopped at the advance reference point P and that the motors M2 and M3 are simultaneously turned on. If the leading end of the previous document has passed the intermediate reference point O 'too much, the motor M2 is driven by adding the number of pulses corresponding to the error Δx during the rise time of the paper feeding motor M2. If the leading end of the previous document has not reached the intermediate reference point O ', the feed motor M
The motor M2 is driven while the number of pulses corresponding to the error -Δx is reduced during the rise time of 2. In this case, the original transport amount per one pulse for driving the paper feed motor M2 is equal to the original transport amount per one pulse output from the encoder E3 of the main motor M3.

Further, in the above two embodiments, when the original is set at the advance feeding position, an error between the leading end and the advance reference point P is also detected, and when the timing of sending the original is corrected, Considering this advance error,
Document exchange can be controlled more accurately. The automatic document feeder according to the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the invention.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an automatic document feeder (ADF) and a copying machine main body according to the present invention.

FIG. 2 is a sectional view showing an internal configuration of the ADF.

FIG. 3 is an explanatory view showing document conveyance in a pre-step mode.

FIG. 4 is an explanatory view showing document conveyance in a pre-step mode, continued from FIG. 3;

FIG. 5 is an explanatory view showing document conveyance in a pre-step mode, continued from FIG. 4;

FIG. 6 is a block diagram showing a drive system.

FIG. 7 is a block diagram showing a CPU 1 for controlling a copying machine main body.

FIG. 8 is a block diagram showing a CPU 2 that controls the ADF.

FIG. 9 is a flowchart showing a main routine of the CPU 1;

FIG. 10 is a flowchart showing a main routine of the CPU 2;

FIG. 11 is a flowchart showing a subroutine of an interrupt process in the CPU 2;

FIG. 12 is a flowchart showing a subroutine for initialization in the CPU 2;

FIG. 13 is a flowchart showing a document exchange subroutine in the CPU 2;

FIG. 14 is a flowchart showing a subroutine of a start check in the CPU 2;

FIG. 15 is a flowchart showing a sheet feeding subroutine in the CPU 2;

FIG. 16 is a flowchart showing a sheet feeding subroutine in CPU 2, and is a continuation of FIG.

FIG. 17 is a flowchart showing a paper feed subroutine in the CPU 2, and is a continuation of FIG. 16;

FIG. 18 is a flowchart showing a sheet feeding subroutine in CPU 2, and is a continuation of FIG. 17;

FIG. 19 is a flowchart showing a sheet feeding subroutine in CPU 2, and is a continuation of FIG. 18;

FIG. 20 is a flowchart showing a subroutine for single-sided document setting in the CPU 2;

21 is a flowchart showing a subroutine for single-sided original setting in the CPU 2, and is a continuation of FIG. 20.

FIG. 22 is a flowchart showing a one-sided document setting subroutine in the CPU 2, and is a continuation of FIG. 21;

FIG. 23 is a flowchart showing a one-sided document setting subroutine in CPU 2, and is a continuation of FIG. 22;

24 is a flowchart showing a one-sided document setting subroutine in the CPU 2, and is a continuation of FIG. 23.

25 is a flowchart showing a subroutine for single-sided original setting in the CPU 2, and is a continuation of FIG. 24.

26 is a flowchart showing a one-sided document setting subroutine in the CPU 2, and is a continuation of FIG. 25. FIG.

27 is a flowchart showing a one-sided document setting subroutine in CPU 2, and is a continuation of FIG. 26. FIG.

FIG. 28 is a flowchart showing a one-sided document setting subroutine in CPU 2, and is a continuation of FIG. 27;

FIG. 29 is a flowchart showing a one-sided document setting subroutine in the CPU 2, and FIG. 28 is continued.

30 is a flowchart showing a one-sided document setting subroutine in CPU 2, and is a continuation of FIG. 29.

FIG. 31 is a flowchart showing a paper discharge subroutine in the CPU 2;

FIG. 32 is a flowchart showing a paper discharge subroutine in CPU 2, and is a continuation of FIG. 31.

FIG. 33 is a flowchart showing a paper discharge subroutine in CPU 2, and is a continuation of FIG. 32.

FIG. 34 is a block diagram showing a drive system according to another embodiment of the present invention.

FIG. 35 is an explanatory diagram illustrating document conveyance in a pre-step mode.

FIG. 36 is an explanatory view showing accumulation of document stop position errors in a pre-step mode.

FIG. 37 is an explanatory diagram showing the correction of the advance feeding position in the pre-step mode.

[Explanation of symbols]

 29: platen glass 50: automatic document feeder 54: pickup roller 58: register roller 60: transport belt O: exposure reference point O ': intermediate reference point P: advance reference point SE12: register sensor SE14: timing sensor CPU2: microcomputer

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yusuke Morikami 2-3-1-13 Azuchicho, Chuo-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Camera Co., Ltd. 430 No. 1 Kobayashi Inside Niska Corporation (56) References JP-A-62-89943 (JP, A) JP-A-1-236138 (JP, A) JP-A-5-262441 (JP, A) Japanese Utility Model No. 4 -94343 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/00 107 B65H 5/02 B65H 7/00-7/20

Claims (3)

(57) [Claims] 1. A sheet feeding means for feeding a stacked document one sheet at a time to an entrance of a platen glass, a conveying means for conveying / stopping the fed document on the platen glass,
When the length of the original is less than half the distance from the exposure reference point on the downstream side in the transport direction to the entrance of the platen glass, in an automatic document feeder composed of a discharging means for discharging the document from the platen glass The document is continuously and intermittently conveyed to a pre-step position where the leading edge of the document is located at an intermediate reference point substantially at the center of the platen glass and an exposure position where the leading edge of the document is located at the exposure reference point, and the next document is transferred. Control means for feeding paper and waiting at the entrance, detecting means for detecting an error in the stop position of the leading end of the document conveyed to the pre-step position, and detecting the error in accordance with the error detected by the detecting means. An automatic document feeder, comprising: a correction unit configured to correct a position where the document waits at the entrance. 2. A sheet feeding means for feeding a document in a stacked state one sheet at a time to an entrance of a platen glass, a conveying means for conveying / stopping the fed document on the platen glass,
When the length of the original is less than half the distance from the exposure reference point on the downstream side in the transport direction to the entrance of the platen glass, in an automatic document feeder comprising a discharge means for discharging the document from the platen glass The document is conveyed continuously and intermittently to a pre-step position where the leading edge of the document is located at an intermediate reference point substantially at the center of the platen glass and an exposure position where the leading edge of the document is located at the exposure reference point. Control means for feeding and leading the original to a standby position at an advance feeding position where the leading end of the original is located at the advance reference point; detecting means for detecting an error in the stop position of the leading end of the original conveyed to the pre-step position; Correction means for correcting the timing at which the next document is sent from the advance paper feed position in accordance with the error detected by the automatic document feeder. . 3. A sheet feeding means for feeding the stacked documents one by one to the entrance of the platen glass, a feeding means for feeding / stopping the fed documents on the platen glass,
When the length of the original is less than half the distance from the exposure reference point on the downstream side in the transport direction to the entrance of the platen glass, in an automatic document feeder composed of a discharging means for discharging the document from the platen glass The document is continuously and intermittently conveyed to a pre-step position where the leading edge of the document is located at an intermediate reference point substantially at the center of the platen glass and an exposure position where the leading edge of the document is located at the exposure reference point, and the next document is transferred. Control means for feeding and leading the original to a standby position at an advance feeding position where the leading end of the original is located at the advance reference point; detecting means for detecting an error in the stop position of the leading end of the original conveyed to the pre-step position; An automatic document feeder, comprising: a correction unit configured to correct a speed at which the next document is fed from the advance paper feed position in accordance with the error detected by the automatic document feeder.