JP2889274B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an image forming apparatus such as a copier, a printer, and an image reader (reading device). More specifically, the present invention relates to operating a scanning unit according to a document size. The present invention relates to an image forming apparatus capable of increasing a reading speed.

<Prior Art> In an image forming apparatus such as a copying machine, an original is read by a reading device, and an image is recorded by a recording unit based on the read information. The document is placed on a platen glass and scanned by scanning means.

However, in order to speed up image processing, there has been proposed a method in which a document is moved in a direction opposite to that of the reading unit at the same time as scanning of the reading unit, and reading is performed when the two pass each other. With this configuration, the scanning speed of the reading unit and the moving speed of the document are combined, so that more rapid image reading is possible.

<Problems to be solved by the invention> However, in the conventional low-pass reading configuration, since the reversing position of the reading unit is fixed, there is a limit to the image processing speed achieved by the reciprocating movement of the reading unit. There have been problems such as a reduction in overall productivity when zooming or depending on the size of the document.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to make it possible to change the reversal position of the scanning unit in the reading unit to maximize the image processing speed achieved by the reciprocating movement of the scanning unit. An object of the present invention is to provide an image forming apparatus that can be improved.

<Means for Solving the Problems> A typical means according to the present invention for solving the problems is to convey a document in a first direction on a platen, and then move the document in a direction opposite to the first direction. Transporting in a second direction,
A document conveying means for conveying the next document in the first direction while discharging the document by the discharging means; a scanning means for exposing and scanning the document while relatively moving with respect to the document conveyed by the document conveying means; Control means for performing an exposure scan of the original while moving the scanning means in a direction opposite to the original transport direction while the original transport means transports the original in the second direction; L ₁ , the recording sheet size L _C , the moving speed of the scanning means S _M , the conveyance speed of the document S _B , the distance from the position where the scanning means and the leading edge of the document match to the reversal position of the scanning means Is L _r , and the distance from the matching position to the discharge means is L ₂ ,
L ₂ / S _B <L _r / S _M , and the control means determines that L _r = S _M · L ₁ /
(S _M + S _B ) or L _r = S _M · L _C / (S _M + S _B ) is calculated, and at the timing when the distance moved by the scanning means from the matching position becomes equal to the calculated L _r. It is characterized in that the scanning means is inverted and the timing of conveying the next document in the document conveying means is controlled.

<Operation> In the above-described unit, reading is performed quickly by setting the scanning unit to be inverted with a minimum necessary moving distance according to the moving speed of the scanning unit, the conveyance speed of the original, the size of the original, and the like. I can do it.

<Example> Next, an example of the present invention to which the above means is applied will be described.

(First embodiment)

FIG. 1 is an explanatory diagram showing the internal structure of the copying machine according to the first embodiment, and FIG. 2 is a block diagram of a control device for driving each member.

First, the overall configuration will be described. This apparatus comprises a document transporting unit A for separating and transporting stacked documents 1 one by one, and a reading unit B for reading an image described on the transported document 1.
And recording means C for recording an image on a recording sheet based on the information read by the reading means B.

The reading means B is reciprocally movable, and is configured to read an image of the document 1 when moving in a direction passing by the document 1 to be conveyed, and to reverse and return to the home position after reading is completed. The reversing of the reading means B can be appropriately changed by the control means in accordance with the size of the document and the like, whereby the document is read efficiently.

Next, the configuration of each means will be specifically described with reference to FIG. 1 and FIG.

A. Document Conveying Means The conveying means A according to the present embodiment is configured to circulate and convey the document 1. When a plurality of documents 1 are set on the stacking tray 2, this is detected by the document set sensor S _1. Is done. Then the half-moon roller 3 and the separation roller 4 when the one-sided document driven by separate motors M _1, are separated one by one from the bottom of the document bundle, once after detection of the registration sensor S ₂ within the path I stop is conveyed stopped via the path I and II to a predetermined position of the platen glass 7 on the entire surface by a belt 6 rotating in the direction of arrow a is a conveyance roller 5 and the first direction is driven by a subsequent belt motor M _2, The entire belt 6 is configured to rotate in the direction b to start the copying operation.

Then, the original 1 conveyed by the entire belt 6 passes through the path II.
The large conveying roller 8 driven by a large conveying roller motor M ₃ through the I sent path IV, to VI, the path IV
And is configured as back to the upper surface of the re-document stack by a discharge roller 9 after the original 1 is detected by the discharge sensor S ₃ that is within.

The transport rollers 8a and 8b are pressed against the outer periphery of the large transport roller 8 to secure the transport force of the original 1 by the large transport roller 8. The document conveying force by the large conveying roller 8 and the conveying roller 8a is configured to be larger than the document conveying force by the full-surface belt 6, whereby the leading end of the document 1 is held between the large conveying roller 8 and the conveying roller 8a. After that, even if the entire belt 6 stops or reverses, the original 1 can be pulled out from the platen glass 7 and discharged.

10 is a recycle lever for detecting the document 1 which is one circulated as above, is constructed as is placed on top of the document stack is rotated by the lever motor M ₄ at the start document feed. And that the trailing edge of the final document the document 1 is sequentially fed to fall under its own weight when exiting the recycle lever 10, which lever sensor S ₄ (the lever 10 sensor S ₄ is turned on when falling) detects To detect one cycle of the original.

On the other hand, when the original 1 is a double-sided screen, as described above, the original 1 is once guided from the paths I, II, and III to IV, and the rotatable switching flapper 11 is switched by the switching solenoid 12 so that the leading end of the original 1 is passed. V, and through the path II again by the rotation of the conveying roller 4, the platen glass 7
It is configured to stop after resending above. That is, the original 1 is reversely conveyed by the large conveying roller 8 along the route of the path IV → V → II.

It should be noted that the original 1 is passed one sheet at a time, pass I → II → III → IV → VI
, And by detecting one cycle with the recycle lever 10, the number of documents 1 can be counted.

B. Reading Means Next, the structure of the reading means B is as follows. The exposure lamp 13 below the platen glass 7 irradiates the original 1 on the platen glass 7 with light, and the reflected light is reflected by the first scanning mirror 14a and the second scanning The image is formed on the photosensitive drum of the recording unit C via the mirror 14b, the third scanning mirror 14c, the lens 15, and the fourth scanning mirror 14d.

The exposure lamp 13 as a scanning unit and a first scanning mirror
14a is integrally formed, and is reciprocally movable in the direction of arrow c and d directions along the platen glass 7 by the driving of the optical system motor M _5. That is, when the original 1 is transported in the direction of arrow b, which is the second direction, the first scanning mirror
14a is configured to move in the direction of arrow c passing therethrough to read an image, and after reading is completed, reverse and move in the direction of arrow d to return to the home position.
Incidentally, the first scanning mirror 14a is whether returns to the home position and is configured as detected by the home position sensor S _5.

C. Recording means The configuration of the recording means C consists of an upper cassette 16a, a lower cassette
The recording sheet 18 is supplied by the supply roller 17a or 17b from the 16b or the manual feed slot 16c, is conveyed in the direction of the photosensitive drum 20 in synchronization with the recording timing from the registration roller 19, and the leading end of a latent image and the leading end of the recording sheet 18 described later are moved. It is configured to be conveyed so as to match.

The surface of the photosensitive drum 20 is made of a photoconductor and a seamless photoconductor using a conductor. The drum 20 is rotatably supported on a shaft, and a main motor that operates in response to pressing of a copy start key (not shown). rotates in the arrow e direction by M _6.
When the predetermined rotation control and potential control processing of the photosensitive drum 20 is completed, the reading means B is driven, and the original reflected light is imaged on the photosensitive drum 20 corona-charged by the high-voltage unit 21 via the exposure unit 22 to form an image. An electrostatic latent image is formed.

The electrostatic latent image is developed by a developing roller 23a of a developing device 23 to be visualized as a toner image, and the toner image is transferred to the recording sheet 18 conveyed at a recording timing by a transfer charger 24. You. After completion of the transfer, the recording sheet 18 is separated from the photosensitive drum 20 by a separation charger 25, guided to a fixing device 27 by a conveyor belt 26, and after the transfer toner is fixed by pressure and heating, is discharged by a discharge roller 28. It is configured to be discharged onto the discharge tray 29.

On the other hand, the photosensitive drum 20 after the toner transfer is configured to rotate as it is and the surface thereof is cleaned by a cleaning unit 30 including a cleaning roller and an elastic blade.

D. Control Means Next, the structure of the control means for driving the above members will be described.

In FIG. 2, reference numeral 31 denotes a CPU for performing arithmetic control for controlling the operation of the entire apparatus. In this embodiment, a microcomputer V50 manufactured by NEC Corporation is used. Three
Reference numeral 2 denotes a ROM in which a control program shown in a flowchart to be described later is stored in advance. The CPU 31 controls driving of each member connected via a bus according to a control procedure stored in the ROM 32. Reference numeral 33 denotes a RAM used as storage for input data, a work storage area, and the like.

34 is an interface (I / O) for outputting a control signal from the CPU31 to the load such as the main motor M _6, motor controller for controlling the speed of the optical system motor M ₅
A speed data signal and a rotation direction signal are output to 35. Further, the interface 34 is connected to the clutch 36 of the supply rollers 17a and 17b, the clutch 37 of the registration roller 19, and the exposure unit 22.

38 is home position sensor S _{5 and} image tip sensor
Enter the input signals such as S ₆ is an interface for sending to CPU 31, 39 is an interface for outputting a control signal from the CPU 31 to a load such as a separate motor M ₁ of the document conveying means A, the speed of the belt motor M ₂ A speed data signal, a rotation direction signal, and the like are output to a controller 40 that performs control.
Reference numeral 41 denotes an interface for inputting input signals from the development set sensor S ₁ , the registration sensor S ₂ , the discharge sensor S ₃ , the lever sensor S _{4, and the} like of the development conveyance means A and sending the signals to the CPU 31. In this embodiment, the interfaces 34, 38, 3
The μPD8255 manufactured by NEC Corporation is used as 9,41.

Referring now specifically described the structure of the controller 35 of the optical system motor M _5, which is configured as shown in Figure 3. In Figure 3, 42 is a PLL controller for performing constant-speed control of the optical system motor M _5, which is a reference frequency corresponding to the rotational speed of interest of the motor as is well known
The FS43 is compared with the FG44 output by electrically converting the rotation speed of the motor 19, and the phase difference is detected and output as a motor drive signal. The FG 44 is input to the interface 38.

Further, the drive output from the oscillator 45 resistor R ₁ and capacitor
A triangular wave 46 and the comparator 47 obtained from C ₁ taken out as a PWM (Pulse Width Modulation) control signal, a drive voltage is applied to the optical system motor M _5. This reciprocating motion of the optical system motor M ₅ are, ▲ ▼ / RV signal 49 outputted from the interface output section 48 of the main body control unit, the signal 49
There This electric current to the optical system motor M ₅ is supplied by the transistor Tr ₁ and Tr ₂ when the "low" level is rotated in the forward direction, the first scanning mirror 14a is moved in the direction of arrow c of FIG. 1. Also, the when the signal 49 is "high" level current is supplied to the optical system motor M ₅ by the transistor Tr ₃ and Tr _4, the motor M ₅ is rotated in the opposite direction, the first scanning mirror 14a is first It moves in the direction of arrow d in the figure. Thereby, the first scanning mirror 14a reciprocates.

Rotational speed of the optical system motor M ₅ is determined by the reference frequency FS43, the FS43 is controls the unit CP
It is output from U31, and any frequency can be set by CPU31. That is, the higher the frequency of the reference frequency FS43, rotational speed of the motor M ₅ becomes faster, when the moving speed of the first scanning mirror 14a can. Lowering the frequency to the contrary, the rotation speed of the motor M ₅ is slow, the motor M ₅ current consumption less to be able to slow down the moving speed of the first scanning mirror 14a of.

Therefore, during the copying operation, the CPU 31 can change the moving speed of the first scanning mirror 14a by changing the frequency of the reference frequency FS43 as necessary.

Motor controller of developing and conveying means A shown in FIG.
The configuration of 40 is the same as the optical motor controller 35 described above.
It can be achieved by the PLL control configuration, and can be controlled to any speed by the frequency of FS50.

The belt FG51 in FIG.
And sent to the CPU 31. Also belt motor M ₂
The driving force is transmitted to the conveying roller 5 and the entire belt 6 via the first clutch 52, and is composed as can disconnect the entire belt 6 the driving force of the motor M ₂ by the first clutch 52. Further, a brake 53 is connected to the entire belt 6 so that the operation of the brake 53 can stop the entire belt 6 instantaneously.

Also provided one-way clutch not shown in the transport roller 5, when the belt motor M ₂ drives reversed so that the driving force to the conveying roller 5 is not transmitted. Further separation motor M ₁ is constructed as capable of driving the separation roller 4 and the conveying rollers 5 independently of the belt motor M ₂ by switching the second clutch 54.

Next, document conveying means A for performing copying in a single-sided document copy mode by the image forming apparatus configured as described above.
The operation procedure of the reading means B will be described. The operation will be described with reference to the operation explanatory diagrams of FIGS. 4A to 4D, the flowchart of FIG. 5, the moving distance explanatory diagram of FIG. 6, and the timing chart of FIG.

As shown in FIG. 4 (A), and placing a document 1 of a plurality on the stacking tray 2, put the recycle lever 10 on the document 1 by a predetermined amount drives the lever motor M ₄ (Step1),
The half-moon roller 3 and the separation roller 4 by a predetermined rotation amount to separate a sheet of the document 1 from the bottom of the document stack and then the separation motor M ₁ is driven a predetermined time, the loop abutted against the distal end to the conveying roller 5 To correct skew by forming (St
ep2).

Thereafter, the conveying roller 5 and the entire surface of the belt 6 of the belt motor M ₂ normal rotation to thereby turn on the first clutch 52 in the arrow a direction at full speed (Step3), document 1
The document 1 is conveyed onto the platen glass 7 via the path II while performing the size detection processing (Step 4).

Then, as shown in FIG. 4 (B), with the trailing edge of the document 1 stops the belt motor M ₂ when it is transported to a predetermined position γ of the platen glass 7, and turns off the first clutch 52, and The brake 53 is turned on to immediately stop the document conveyance (Steps 5 and 6).

Then perform optics inverted data processing (Step7), and at the same time moving the first scanning mirror 14a by the optical system motor M ₅ and driven forward at a predetermined set speed by the PLL speed control in the arrow c direction, the belt motor the M ₂ is driven reversely by the PLL speed control at a predetermined set speed rotating entire belt 6 in the direction of arrow b (Step8,9).

And when the home position sensor S ₅ is turned off,
That is, when the first scanning mirror 14a reaches the β point, the brake 5
3 is turned off and the first clutch 52 is turned on to
At a set speed in the direction of arrow b (Steps 10 and 11). As a result, the first scanning mirror 14a and the original 1 move at a set speed in directions that pass each other.

Next, as shown in FIG. 4 (C), starts reading the document 1 from the time point (alpha point) the tip of the first scanning mirror 14a and the document 1 by detecting the image tip sensor S ₆ is met, the reading At the same time as the operation, a latent image corresponding to the read information is formed on the photosensitive drum 20, and the image is recorded on the recording sheet 18. Furthermore unless the lever sensor S ₄ is turned on when the carried the reading operation and the document 1 of the first sheet in parallel, that is, recycle lever 10 has not fallen second sheet of the document 1 is tray to present on 2, after correcting the skew form a loop by conveying the separated motor M ₁ and the second clutch 54 is turned on a predetermined time the leading edge of the second sheet of the document 1 to the transport roller 5 The tip is conveyed to a position immediately before the platen glass 7 (point δ) and is made to stand by (St.
ep12-16). This is to minimize the document transport time when reading the second and subsequent documents.

In the reading operation, as shown in FIG. 4D, the first scanning mirror 14a performs the optical system inversion data processing (the Step
The processing is executed until the position corresponding to the data set in 7) is reached (Step 17), and at this point, the reading of the first sheet is completed (Step 18).

When reading the document 1 and as the ends, the return of the first scanning mirror 14a to the home position by the optical system motor M ₅ is driven to rotate in reverse (Step 19), to drive the large conveying roller motor M ₃ document 1 when there is the conveyance to convey large roller 8 (step 20) the following second sheet after the original 1, that is, when the lever sensor S ₄ is oFF returns to (step 21), step 3 of Figure 5 two The first document 1 is conveyed onto the platen glass 7. At this time, before the read original 1 returns to the stacking tray 2, the second original 1 is conveyed onto the platen glass 7 by the rotation of the entire belt 6. Roller 8 and transport roller
There is no problem because it is added to 8a.

In parallel with the original loading operation, the first scanning mirror 14a
Detects whether or not has returned to the home position (Step 2
2), to stop the optical system motor M ₅ In the time of returning the causes wait to the home position (Step 23), the fifth
Returning to step 4 in the figure, the process waits until the rear end of the second original 1 stops at the predetermined position γ of the platen glass 7.

On the other hand, in step 21, when there is no original 1 on the stacking tray 2, that is, when the lever sensor S ₄ is ON, the original 1 is returned to the stacking tray 2 by the large conveying roller 8 and the reading operation is completed. (Steps 24 and 25).

Next, the relationship between the movement of the first scanning mirror 14a and the movement of the original 1 by the entire belt 6 in the reading will be described with reference to FIG. The moving speed of the first scanning mirror 14a in the direction of arrow c is S _M , the moving speed S _B of the original 1 in the direction of arrow b by the full-surface belt 6, the rotational peripheral speed S _D of the photosensitive drum 20, and the moving speed of the original 1. The length is l ₁ , the distance from the matching position α between the first scanning mirror 14a and the document 1 to the nip position between the large conveying roller 8 and the conveying roller 8a is l ₂ , and the first scanning mirror 14a _Let l _r be the distance to the position that matches the rear end of 1.

At the time of image reading, the first scanning mirror 14a and the original 1 move in mutually passing directions, and the relative speed difference between the two is S _M + S _B , and this is equal to the peripheral speed S _D of the photosensitive drum 20 ( S _M + S _B = S _D ) Set. Thereby, the reading means B
The same latent image is used when the photosensitive drum 20 is used and when it is not used.
And the same recording can be performed.

In order to speed up the timing of loading the next original into the platen glass 7, the leading end of the original that has been read must have already been nipped between the large transport roller 8 and the transport roller 8a at the end of the read. For that purpose l ₂ / S _B
<It is necessary to satisfy the relationship of l _r / S _M. Where l _r = l ₁ −l ₂
It is.

Therefore, if the speed is set so as to satisfy the conditions of S _M + S _B = S _D and l ₂ / S _B <l _r / S _M , it is possible to perform the document exchange operation completely ignoring the time lost by the passing operation. It is what becomes.

Next, a description will be given of image registration by moving the first scanning mirror 14a and the original 1. In this embodiment, as shown in the timing chart of FIG.
The movement of the original 1 stopped at the point
14a (see FIG. 4 (B)) is performed when it reaches the β point exiting the home position sensor S _5, both consistent with α point by such image tip sensor S ₆ at this time it is turned on The image destination is set to be the same as when scanning without sending a normal document.

In order to match at this α point, the first scanning mirror 14a
Setting There and time T _M required to reach α from point β point, the γ points so the document 1 and the time T _B required for the first clutch 52 reaches α from point γ point is turned on becomes equal to Just do it. The time T _B is the time required for the entire belt 6 is constant speed from a stopped state, although there is uncertainty factors, for example the be easily realized by performing the position adjustment of each point. Also, if the movement timing is shifted due to the aging of clutches and motors, etc.,
For example a belt FG51 by CPU31 checks constantly counts within the time T _B, it suffices to move the position of the γ point by correcting the amount of deviation.

Next, a document size detection processing procedure (step 4 shown in FIG. 5) for changing the reversal position of the first scanning mirror 14a according to the document size will be specifically described with reference to the flowchart in FIG.

Counted by the clock signal The procedure for entering the document 1 by first driving the conveying roller 5 and the entire surface of the belt 6 of the belt motor M ₂ in order to transport the path II from the path I from the belt clock interrupter (not shown) and simultaneously driven forward The size check counter to be started is started (Step 41).

The document 1 is conveyed to stop the size check counter at the same time as the rear end has passed the registration sensor S ₂ (Step42,43), conveying rollers 5 to the data
Those corrected by adding the distance fraction to resist sensor S ₂ is the true original size l ₁ from the nip position (Step4
Four). Accordingly, and it sends the data of the document size l ₁ that the detected device body, and then returns to initialize the size check counter (Step45,46). Thus, the size of the document 1 conveyed is detected.

Then the document size l ₁ optical system reversal data processing procedure for setting the reversing position of the first scanning mirror 14a according to (step 7 of FIG. 5) is as shown in the flowchart of FIG. 9, the document size detection apparatus main body data of a document size l ₁ obtained in the process receives (sTEP 71), the moving speed S _M of the first scanning mirror 14a to be set by the PLL speed control in step 8 and step 9 of this data and Figure 5, by the belt moving speed of the document 1 by the motor M ₂ S _B, the distance l _r to the inverted position of the first scanning mirror 14a shown in FIG. _{6, l r = S M · l} 1 / (S M + S B) …… (1) is calculated and this is set as inverted data (St
ep72).

Therefore, when the distance the first scanning mirror 14a is moved from the at image tip matches point α in Fig. 6 is equal to the inverted data length l _r, is determined inversion timing in step 17 of FIG. 5 , The first scanning mirror 14α is inverted from that position. As a result, the first scanning mirror 14α is inverted according to the size of the original, so that the original can be read quickly without any loss.

(Second embodiment)

Next, an embodiment in which the reversal position of the first scanning mirror 14a is variably set according to the cassette size (the size of the recording sheet 18) selected by the operator and the copy magnification will be described.

In this case, the optical system inversion data processing is performed as shown in the flowchart of FIG.

For example, in the apparatus shown in FIG. 1, it is first determined whether or not the operator has selected the upper cassette 16a (Step 7).
1), if it is selected to set the cassette size l _c the upper cassette size (e.g. B5 size) (Step7
2). When the upper cassette 16a is not selected at step 71 and then determines whether lower cassette 16b is selected (STEP 73), lower cassette size cassette size l _c if selected (e.g., B4 Size) (Step 74). Further, in step 73, the lower cassette 16
b is when not selected, sets the maximum size of the manual feed mode may be used in the apparatus of the cassette size l _c was determined to be selected (e.g., A3 size) (STEP 75).
Then, the copy magnification m (for example, 2 times) set by the operator is set (Step 76).

Then said cassette size l _c and copying magnification m, by the moving speed S _B of the document 1 by the driving of the moving speed S _M and the belt motor M ₂ of the first scanning mirror 14a, the first scanning mirror 14
The inverted data l _r of a, as inverted data of _{l r = (S M · l} c / m) / (S M + S B) is calculated as a ... (2), in step 7 it in FIG. 5 Set (Step 77).

In this way, the first scanning mirror 14a is to reverse in response to the copy magnification m and cassette size l _c.

(Third embodiment)

Then in the case where the inversion point of the first scanning mirror 14a as a third embodiment, calculated according to the moving speed S _B and the document size l ₁ of the moving speed S _M and the document 1 in the first scanning mirror 14a, the recording comparing the case where the calculated depending on the size l _c and copying magnification m of the sheet 18, a description will be given of an embodiment for setting a reverse timing travel distance by selecting shorter of the first scanning mirror 14a in the comparison.

In this case, the optical system inversion data processing is performed as shown in the flowchart of FIG.

First, as described in the first embodiment, the document size is received (Step 71), and the first scanning mirror corresponding to the document size is received.
The inverted data l _{r1 of} 14a is calculated as l _r1 = S _M · l ₁ / (S _M + S _B ) in the same manner as in the above equation (1) (Step 72).

The operator then has the aforementioned inverted data l _r2 of the first scanning mirror 14a by the cassette size l _c and copying magnification m selected (2) l _r2 = in the same manner as _{(S M · l c / m} ) / ( S _M + S _B ) (Steps 73 to 75).

Next, the data l _r1 and l _r2 are compared by a comparison means such as an operational amplifier or the like (Step 76). If l _r1 ≧ l _r2 , the data l _r2 is set as inverted data, and if l _r1 <l _r2 , Data l _r1 is set as inverted data (Step 77, 7
8).

With this, data calculated according to the document size,
By inverting the first scanning mirror 14a according to the short distance of the data calculated according to the cassette size and the copy magnification, it is possible to perform efficient image reading in a shorter time.

<Effect of the Invention> As described above, according to the present invention, image reading can be efficiently performed by relatively moving the original reading and scanning unit and the original in opposite directions.
The control is performed in accordance with the document size, the size of the recording sheet, the speed at which the document is conveyed, the moving speed of the scanning means, the distance from the position where the scanning means coincides with the leading edge of the document to the discharge means, etc. By controlling the document conveyance timing, the image forming processing speed due to the reciprocal movement of the scanning means can be maximized, and the overall productivity can be greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the internal structure of a copying machine according to an embodiment of the present invention, FIG. 2 is a block diagram of a control device for operating each member, FIG. 3 is a drive circuit of an optical system motor, FIG. 5A and 5B are flow charts of the document conveying means, and FIG. 6 is a diagram showing the moving speed of the first scanning mirror and the document and the moving distance of the first scanning mirror. FIG. 7 is an explanatory view, and FIG.
FIG. 8 is a flowchart showing a document size detection processing procedure, FIG. 9 is a flowchart showing an optical system inversion data processing procedure, FIG. 10 is a flowchart showing an optical system inversion data processing procedure according to the second embodiment, and FIG. 9 is a flowchart showing an optical system inversion data processing procedure according to the third embodiment. A image reading unit, B is reading means, C is a recording unit, S ₁ is the original set sensor, S ₂ resist sensor (original)
S ₃ is a discharge sensor (document), S ₄ is a lever sensor, S ₅ is a home position sensor, S ₆ is an image sensor, M ₁ is a separation motor, M ₂ is a belt motor, M ₃ is a large roller motor, M ₄ is a lever motor, M ₅ is an optical motor, M ₆
Is a main motor, 1 is a document, 2 is a loading tray, 3 is a half-moon roller, 4 is a separation roller, 5 is a conveyance roller, 6 is a full-surface belt, 7 is a platen glass, 8 is a large conveyance roller, 8a, 8
b is a conveying roller, 9 is a discharge roller, 10 is a recycle lever, 11 is a switching flapper, 12 is a switching solenoid, 13 is an exposure lamp, 14a to 14d are first to fourth scanning mirrors, 15 is a lens, 16a and 16b are A cassette, 16c is a hand slot, 17a and 17b are supply rollers, 18 is a recording sheet, 19 is a registration roller, 20 is a photosensitive drum, 21 is a high-pressure unit, 22 is an exposure unit, 23 is a developing device, 23a is a developing roller, 24 is a transfer charger, 25 is a separation charger, 26 is a conveyor belt, 27 is a fixing device, 28 is a discharge roller, 29 is a discharge tray, 30 is a cleaning unit, 31 is a CPU, 3
2 is ROM, 33 is RAM, 34 is interface, 35 is motor controller, 36 is supply roller clutch, 37 is resist clutch, 38 is interface, 39 is interface, 40 is controller, 41 is interface, 42 is
PLL control unit, 43 is FS, 44 is FG, 45 is oscillator, 46 is triangular wave, 47 is comparator, 48 is interface output unit,
49 is a ▲ ▼ / RV signal, 50 is FS, 51 is a belt FG, 52 is a first clutch, 53 is a brake, and 54 is a second clutch.

────────────────────────────────────────────────── ⁶ Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI H04N 1/04 105 H04N 1/12 Z (56) References JP-A-63-249864 (JP, A) JP-A-58-192028 (JP, A) JP-A-60-214348 (JP, A) JP-A-55-172950 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/00 107 G03G 21 / 00 370-540 G03G 21/14 G03G 13/04-13/05 G03G 15/04-15/05 G03G 27/50

Claims (3)

(57) [Claims] An original is transported on a platen in a first direction, and then the original is transported in a second direction opposite to the first direction. Document transport means for transporting the document in the first direction; scanning means for exposing and scanning the document while moving relative to the document transported by the document transport means; and the second direction of the document by the document transport means during transport to, and a control means for causing the exposure scanning of the original document while moving the scanning means in a direction opposite to the conveying direction of the document, the document size L _1, a recording sheet size L _C The moving speed of the scanning unit is S _M , the conveying speed of the document is S _B , the distance from the position where the scanning unit matches the leading edge of the document to the inversion position of the scanning unit is L _r , and the distance from the matching position is L _r . when the distance to the discharge means to the L _2, L ₂ / S _B <L _r / S _M , wherein the control means is L _r = S _M · L ₁ / (S _M + S _B ) or L _r = S _M
Calculating L _C / (S _M + S _B ), inverting the scanning means at a timing when the distance moved by the scanning means from the matching position becomes equal to the calculated L _r, and An image forming apparatus for controlling a timing of conveying a next document. 2. An image forming apparatus according to claim 1, wherein a document conveying force by said discharge means is larger than a document conveying force when the document is conveyed on said platen in a first direction. 3. The apparatus according to claim 2, wherein the control means calculates the original based on a moving speed of the original and the scanning means and a size of the original.
And L _r, comparing the L _r, which is determined based on the size of the moving speed and the recording sheet of the document and the scanning means means, the moving distance by selecting L _r towards shorter determining reversal timing The image forming apparatus according to claim 1, wherein: