JPH0266571A - Automatic document feeding type copying machine - Google Patents

Abstract

PURPOSE:To shorten a time required for copying action by measuring a predetermined time after a detecting means detecting a leading edge generates a detecting signal. CONSTITUTION:After a detecting means DSD1 detecting at last the leading edge generates a detecting signal in the carrying direction of a document D supported by a supporting means 47. The signal generating means generates a counting signal in synchronization with the speed that the supporting means 47 carries a document. After a counting means measures a predetermined time based on the signal from the signal generating means, copying paper is started to be carried to a photosensitive body. In such a way, even if a document is freely supported by the supporting means 47 to perform reading and exposing actions, a picture on a photosensitive body can be surely transferred onto the carried copying paper. Thus, the period for reading the document can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic copying machine, and particularly to an electrostatic copying machine for copying sheet-like originals.
Circulating automatic document feeder (rRDH
The present invention relates to an automatic document feeding type copying machine equipped with a copying machine (referred to as J) and the like.

Conventional technology Optical reading devices, such as transfer-type electrostatic copying machines, which optically read the original image by exposing the surface of the original to slit light, read sheet-shaped originals by exposing the front surface of the original to light. In some cases, an RDH or the like that automatically transports the image to the reading area is used.

FIG. 7 shows a transfer type electrostatic copying machine 1 equipped with a conventional RDH.
FIG. At the top of the body of the copying machine 1, an RDH 2 and a thick document pressing plate 3 are provided. In order to copy the sheet-like original 4, this sheet-like original 4 is
The documents are stacked and stored in the document storage section 5 in the DH2. The originals 4 stored in the original storage unit 5 are fed one by one by a paper feed roller 6 and conveyed toward a first support tube 7 having a right cylindrical shape. Registration rollers 8 are provided immediately in front of the first support cylinder 7, and the registration rollers 8 hold the original 4, and determine the timing for transporting the first support cylinder 71\original 4.
It is controlled as described above. The first support cylinder is provided with suction means and the like, and the transported original 4 is brought into close contact with the first support cylinder. The downstream end of the document 4 in the conveyance direction that is in close contact with the first support tube is held by a retaining plate 9 (see FIG. 8) provided on the outer peripheral surface of the first support tube 7. It is conveyed onto the first transparent plate 11 of the first reading area 10 provided at the lower part of the cylinder 7. The support area 12 on the outer peripheral surface of the first support @7
At this point, the driving timing of the registration rollers 8 is adjusted so that the downstream end of the original 4 in the transport direction coincides with the rotated holding plate 9, and the downstream end of the original 4 in the transport direction is held on the holding plate 9. is controlled.

On the first transparent plate 11 One surface of the transported original 4 facing the first transparent plate 11 is irradiated with light from an exposure lamp 13 provided near the first reading area 10; A reading exposure operation is performed on the surface of the image. In the first reading area 10 , the original 4 whose one surface has been read is conveyed to the second support cylinder 15 via the original reversing means 14 . A registration roller 16 similar to the registration roller 8 is provided immediately in front of the second support jump 15 . The registration rollers 16 are controlled in the same way as the registration rollers 8 described above, and are
is transported to the second support cylinder 15. A second reading area 18 including a second transparent plate 17 is provided at the bottom of the second support cylinder 15, and the other surface of the document 4 that has not yet been read is read and exposed.

The original 4 whose both sides have been read is returned to the original storage unit 51 and stored.

In each reading area 10.18, the light from the exposure lamp 13 of one optical system is irradiated onto one of the surfaces of the original 4, and the reflected light from the surface of the original 4 passes through the optical system 19 and onto the photoreceptor 20. An image is formed in the exposure area 21. Photoreceptor 20
is driven to rotate in the direction of arrow 22. First, in the upper part of FIG. A latent image is formed. The electrostatic latent image formed is
The toner image is visualized by the developing device 24.

Further, the copy paper 25 is first fed from a cassette 26 or the like by a paper feed roller 27, and is conveyed toward the photoreceptor 20. Registration rollers 28 are provided immediately before the photoconductor 20, and the registration rollers 28 sandwich the copy paper 25, and the timing of conveying the copy paper P onto the photoconductor 20 is controlled. A drive motor that transmits rotational power to the drive shaft is connected to the drive shaft via a registration roller drive clutch PSC (not shown).The toner image visualized on the photoreceptor 20 as described above is , the registration roller drive clutch PSC is switched from the on-state layer to the on-state layer so that the image is reliably transferred onto the conveyed copy paper 25 in the two transfer regions where the transfer corona dischargers are provided. By starting to drive the registration rollers 28, the timing of conveyance of the copy paper 25 is controlled.

The transferred copy paper 25 is conveyed to the fixing device 30 and fixed, completing the copying of one surface. In order to make a copy on the other surface of the copy paper 25 that has not yet been copied, the copy paper 25 is transferred to the intermediate tray 32 via a copy paper reversing means 31.
transported to. The copy paper 25 is again fed from the intermediate tray 32 and conveyed onto the photoreceptor 20, and a copying operation is performed on the other surface l\ which has not yet been copied. The copy paper 25 on which the copying operation has been completed is discharged to the bin 33.

Problems to be Solved by the Invention Conventionally, a holding plate for holding the downstream end in the conveyance direction of a document conveyed to the support tube is provided on a predetermined outer peripheral surface of the support tube. That is, since the downstream end in the conveyance direction of the original document that is closely attached to the support tube is always a part of the holding plate, the position where the document is closely supported on the support tube is always the same and predetermined position.

In order to cause the holding plate to hold the downstream end of the original in the transport direction in the support area, the timing of transporting the original onto the support cylinder must be controlled by the registration rollers. In other words, in order to hold the document on the holding plate in the support area on the support tube, the document must wait at the registration roller until the holding plate comes just in front of the support area. It takes a lot of time to convey the original to the reading area, and the entire copying operation of the copying machine takes time.

Conventionally, the position of this holding plate on the support cylinder is predetermined, so that the downstream end of the document supported on the support cylinder in the conveyance direction cannot be detected by the central processing circuit of the control device in the copying machine. can. Therefore, after the original is held on the holding plate, the surface of the original is read, and the registration rollers that transport the copy paper are driven/stopped so that the read original image is transferred onto the copy paper on the photoreceptor. Timing control is easily performed by using counters, timers, etc. within the central processing circuit.

If the above-described waiting time for the original document can be eliminated and the original document can be supported on the support cylinder at will without being constrained by the position of the support cylinder-shaped holding plate, the time required for the copying operation can be shortened. However, if the holding plate is not provided and the document is arbitrarily supported on the support tube, the downstream end in the conveying direction of the document supported on the support tube cannot be detected. Therefore, the above-mentioned timing for conveying the copy paper is determined by register ■−.
Since the image cannot be controlled by the roller, the image corresponding to the surface of the original document cannot be transferred onto the copy paper during transfer on the photoreceptor, resulting in poor performance as a copying machine.

An object of the present invention is to solve the above-mentioned problems, and it is possible to arbitrarily support a document on a support tube,
Furthermore, in order to transfer the copy paper onto the photoreceptor, we are able to control the conveyance of the copy paper onto the photoreceptor, thus reducing the time required for the copying operation as a copying machine. It is about providing.

Means for Solving the Problems The present invention provides a copying machine that optically scans the original while supporting the original on a support means and rotating the support means in the original transport direction, the original being supported by the support means. detection means for detecting at least the leading edge along the conveyance direction of the document; signal generation means for generating a clock signal in synchronization with the document conveyance speed by the support means; and a clock means for measuring a set time, and after the detection signal is generated from the detection means and the set time is measured by the clock means based on the clock signal of the signal generating means, conveyance of the copy paper is started. This is an automatic document feeding type copying machine.

fY According to the present invention, in a copying machine that optically scans an original while supporting the original on a supporting means and rotating the supporting means in the original transporting direction, the original is supported by the supporting means in the transporting direction. After the detection means for detecting at least the leading edge along the document generates a detection signal, the signal generation means generates a clock signal in synchronization with the document conveyance speed by the support means. After a predetermined set time is measured by the clock means based on the clock signal from the signal generating means, conveyance of the copy paper to the photoreceptor is started.

According to the above-described operation, even if the document is arbitrarily supported by the supporting means and the reading exposure operation is performed, the document can be reliably transferred onto the copy paper conveyed on the photoreceptor. Therefore, the time required for the reading operation of this original can be shortened, and further the time required for the copying operation of the copying machine can be shortened.

Embodiment A, Structure FIG. 1 is a simplified sectional view of an automatic original feeding type copying machine 11!140 which is an embodiment of the present invention. At the top of the body 41, there is a circulating automatic document feeder (hereinafter referred to as [RD HJ) 42 for reading and exposing a sheet document.
and a thick original press plate 4 for covering thick originals such as books.
3 is provided.

Furthermore, a first transparent plate 44, a second transparent plate 45, and a third transparent plate 46 are provided on the upper part of the body 41. The first transparent plate 44 is attached to the lower part of the first support cylinder 47 inside the RDH 42.
A reading area 48 is provided. Second transparent plate 45
are provided for the second reading area 50 at the bottom of the four second support cylinders in the RD H42. Further, the third transparent plate 46
is the press for thick originals [No. 3 at the bottom of 43 for reading thick originals.
A reading area 51 is provided.

A document detection element DSDI is provided near the outer circumferential surface of the first support tube 47 on the right cylinder to detect the conveyance position of a sheet-like document on the first support tube 47 .

FIG. 2 is a simplified cross-sectional view of the document detection element DSDI and its surroundings. As the detection element DSD 1, for example, a reflective photodetection element is used. The DSD1 includes a light emitting element 52 such as an LED, and a light receiving element 53 such as a photodiode that detects reflected light from the light emitting element 52 as will be described later. The light emitted from the light emitting element 52 is irradiated toward the outer peripheral surface of the rotating first support tube 47.

The outer peripheral surface of the first support tube 47 is treated with a color having a low reflectance, and most of the light emitted from the light emitting element 52 is reflected on the outer peripheral surface of the first support tube 47. do not. Therefore, the light emitted from the light emitting element 52 does not reach the light receiving element 53/\, and the detection element DSDI is in an off state. This first support tube 47/\\The original document to be read for copying is conveyed, and this document document is closely supported by the first support tube 47, and the switching area 54 on the outer peripheral surface of the first support tube 47 , the light emitted from the light emitting element 52 is reflected by the surface of the document tray, which has a higher reflectance than the outer peripheral surface of the first support tube 47 . The reflected light reaches the light receiving element 53, and the detection element DSD1 is turned on. That is, the detection element DSDI is switched from the OFF state to the ON state when the downstream end Df in the transport direction of the document, which has been transported while being closely supported by the first support cylinder 47, passes through the switching area 54. The detection element DSD 1 is switched from the on state to the off state when the upstream end Dr in the conveying direction of the document passes through the switching area 54 . Further, near the outer circumferential surface of the second support cylinder 49, a reflective light detection element is provided as a similar document detection element DSD2. Note that each detection element DSDI
, DSD2 is generally referred to as DSD.

Also, inside the body 41, there is an optical system 56 that guides the surface of the document read in each reading area 48.50° 51 to the photoreceptor 55;
A copying section 57 centered around a photoreceptor 55, and a copy paper transport path 5 that transports a copy paper P for copying a pattern corresponding to a document.
8 is provided.

When copying sheet-like originals, the sheet-like originals [ ) are stored in a stack in a document storage section 61 provided in the RDH 42 . When copying starts, the document is sequentially fed one by one by the paper feed roller 62 from the top, and guided to the transport start opening 64 of the transport path 63. At the conveyance start port 64, even if two or more overlapping documents are guided by the action of the sorting roller 65, etc.,
The sheets are separated one by one and transported to the transport path 63. The document conveyed through the conveyance path 63/\ is conveyed to the first support cylinder 47. Immediately before the first support tube 47, the first support tube 47
Registration rollers are not provided to control the timing of conveying the original document to the first support cylinder 47, and the original document conveyed through the conveyance path 63 is arbitrarily conveyed to the first support cylinder 47.

A suction port (not shown) or the like is formed on the outer peripheral surface of the first support cylinder 47 which is rotationally driven in the direction of arrow 59, and a suction means is connected inside. The document is conveyed by the drive of the suction means, is closely supported by the first support cylinder 47, and is conveyed to the first reading area 48/\.

When the downstream end Df of the document in the conveyance direction passes through the switching area 54 while the document is being conveyed to the first reading area 48, the detection element DSD1 is switched from the OFF state to the ON state. After passing through the switching area 54, the document passes over the first transparent plate 44 provided in the first reading area 48. One surface of the original document passing over the first transparent plate 44 is irradiated with light from an exposure lamp 66 of the optical system 56, and a reading exposure operation to be described later is performed.

FIG. 3 is a simplified cross-sectional view of the first support tube 47 and its surroundings. The downstream end Df of the original in the conveying direction is the switching area 54
The center position 1t67 of the first transparent plate 44, which is located at a distance of conveyance distance 11 from
pass later. That is, based on the set time T l after the detection element DSDI is switched from the OFF state to the OFF state, the downstream end Df of the original document in the conveying direction reaches the center position 67 of the first transparent plate 44, and the reading exposure movement (ya starts.

The first reading area 48 is irradiated with light from the exposure lamp 66
The reflected light from one surface of the original document passing over the first transparent plate 44 passes through the optical path 68 of the optical system 56 and is focused in the exposure area 70 of the photoreceptor 55 which is being rotated toward the arrow 69. Image. The optical system 56 is exposed to light, the professional 6, and the reflector 7.
1.72, 73, zoom lens 74, and reflector 75
It consists of:

The photoreceptor 55, which is being rotated by the arrow 69/\, is first charged by the main corona discharger 76 in the upper part of FIG.

When the charged photoreceptor 55 rotates to the exposure gt area 70, the reflected light from one surface of the document tray is condensed in this exposure area 70. An electrostatic latent image is formed.This electrostatic latent image is transferred to the developing device 7.
7, the toner image is developed into a toner image, and is transferred in a transfer area 78 to a copy paper P conveyed by seven transfer type corona dischargers as will be described later.

Copy paper P is fed from a cassette 80 by a paper feed roller 81 and conveyed to a conveyance path 82. The conveyance end end of the conveyance path 82 includes a registration roller 83 that controls the timing of conveyance of the copy paper P, and a reflective detection element that detects whether or not the copy paper P has been conveyed to the position of the registration roller 83. A copy paper detection element MS is provided. A drive circuit such as a motor is connected to the rotational drive shaft of the registration roller 83 via a registration roller drive clutch PSC that functions as a conduction/cutoff switch when transmitting rotational power to the drive shaft. . Copy paper P is on conveyance path 8
2 and passing through the position where the detection element MS is provided, the detection element MS is kept on. Also,
When the copy paper P is not present at the position where the detection element MS is provided, the detection element MS is in an OFF state. Copy paper P
Since the clutch PSC is in the OFF position until the timing for conveying the paper, the registration rollers 83 are not driven and are stopped. Therefore, the copy paper P that has been conveyed through the conveyance path 82 waits at the position of the registration rollers 83. are doing.

FIG. 4 shows a simplified diagram of the photoreceptor 55 and registration roller 83.
FIG. The rotational circumferential speed of the registration roller 83 during rotation and the rotational circumferential speed V2 of the photoreceptor 55 during rotation are the same speed. A transfer area 78 where a toner image in which an electrostatic latent image is visualized is transferred onto copy paper P.
The moving distance @12 is longer than the conveyance distance 13 by which the copy paper P is conveyed from the position of the registration roller 83 to the transfer area 78. Therefore, after the downstream end in the moving direction of the electrostatic latent image begins to be formed in the exposure area 70, the downstream end in the moving direction of the electrostatic latent image moves along the outer peripheral surface of the photoreceptor 55 by a moving distance 14 according to the first equation. After the set time T2 required for this, the clutch PSC is switched from the OFF state to the OFF state to drive the registration roller 83 and transport the copy paper P to the transfer area 78 on the photoreceptor 55, thereby removing the electrostatic latent image. The downstream end of the toner image visualized on the photoreceptor 55 in the moving direction coincides with the downstream end Pf of the copy paper P in the transporting direction in the transfer area 78 .

14=12-13...(1) Time required for the light from the exposure lamp 66 of the optical system 56 to pass through the optical path 68 and form an image at the exposure mH70 after being reflected on one surface of the document tray is so small that it can be ignored. That is, the time when the downstream end Df of the document in the conveyance direction reaches the center position 67 of the first transparent plate 44 is the time when the
There is no problem in assuming that this is the time when an electrostatic latent image corresponding to one surface of the document tray begins to be formed in the exposure area 70 of . Therefore, after the downstream end Df in the conveyance direction of the original document supported by the first support cylinder 47 passes through the switching unit +454 and the detection element DSDI is switched from the OFF state to the ON state,
After the set time T3 according to the system 1 of the second equation, the clutch PS
Switch C from off state to on state, and register roller 8
By starting the drive of 3 and conveying the copy paper P,
The downstream end in the moving direction of the toner image formed on the photoreceptor 55 corresponding to one surface of the document sheet read on the first reading area 48 is the downstream end in the conveying direction of the copy paper P in the transfer type IA78. Matches Pf. That is, the toner image formed on the photoreceptor 55 and corresponding to one surface of the document sheet is reliably transferred onto the copy paper P. The copy paper P on which the transfer has been performed is transported by the transport means 84 to the fixing device 85/\, where fixing is performed and the copying operation on one surface is completed.

T3=T1+T2... (2) The original document which has completed the reading exposure operation on one front side by the first reading area 4S is then conveyed to the second support tube 49 via the document reversing means 86. .

The second support cylinder 49 has the same structure as the first support cylinder 47, and supports the transported document in close contact with it. Second
The document supported by the support cylinder 49 passes over the second transparent plate 45 in the second reading area 50 and is still in the first reading area 4.
The light from the exposure lamp 66 that has moved from the first reading area 48 to the second reading area 50/\ is irradiated onto the other surface that has not been read in step 8, and a reading exposure operation is performed.

A document detection element DSD2 is provided near the second support cylinder 49 in the same way as the vicinity of the first support cylinder 47 in FIG. After T3, the clutch PSC is switched from the OFF state to the ON state, the registration roller 83 is driven, and the copy paper P waiting at the registration roller 83 is transferred to the transfer type I! l
i78/\Transfer and transfer the image. The document trays whose both sides have been read as described above are returned to the bottom of the document trays stacked and stored in the document storage section 61 and stored therein.

In addition, when one side of the copy paper P is copied, i.e., one-sided copying is performed, the copy paper P, on which one surface I\ has been copied, passes through the conveyance means 85 and is transferred to the conveyance path 8.
7 and is discharged to a bin 88.

Furthermore, when the other side, which has not yet been copied, is copied, ie, so-called double-sided copying is performed, the copy paper P on which the copying on the - side has been completed is conveyed to the copy paper reversing means 89. Copy paper reversing means 8 transport paths 90-93/\
The conveyed copy paper P is discharged to an intermediate tray 95 by a conveyance roller 94 and stored therein. The copy sheets P stored in the intermediate tray 95 are stored so that one surface on which copying has been completed faces upward in FIG.

The copy paper P stored in the intermediate tray 95 is fed to the paper feed roller 96.
The paper is fed again by the controller, and is transported again to the transport path 82 via the one-layer transport path 97, and is subjected to the same control (distribution) as described above by the registration rollers 83, and the transfer area 7 on the photoreceptor 55 is
At 8, the transfer is made to the other surface which has not yet been copied.

First, the copy paper P passes through the conveyance means 84 and then passes through the fixing device 8.
Fixed at 5. The copy paper P on which both sides l\ have been copied is discharged to the bin 88 via the conveyance path 87.

Note that FIG. 1 shows a cassette 98.9 other than the cassette 80.
9 are provided, each having a different size.
are stored, and paper feed rollers 100, 1 can be adjusted depending on the application.
01 through the transport path 82/\. Further, when the rotational drive/stop of the registration roller 83 is controlled according to the above-mentioned timing, if the copy paper detection element MS is not switched from the OFF state to the ON state by the time when the registration roller 83 is driven to make a straight turn, the copy paper This indicates that the copy paper P has not been conveyed to the registration rollers 83 even though it is the timing to start conveyance. Therefore, since the copy paper P cannot be transported and the copying operation cannot be performed, other processing such as temporarily stopping the electrical system within the machine body 41 is performed.

B. Derivation of set time The respective set times Tl and T2 described above are derived below. The first support tube 47 is moved to the arrow 59, and then the second support tube 49 is moved to the arrow 59.
A pulse generator E that generates pulses in synchronization with the circumferential rotation speed of the first support tube 47 is connected to the drive circuit of the motor that rotates the first support tube 47 in the direction of the arrow 60 . A central processing circuit CPU provided in the control device of the aircraft body 41 is provided with a counter C that detects the number of pulses generated by the pulse generator E, and a timer T that measures a predetermined set time. By this counter C and timer T, the above-mentioned set time Tl,
Measure T2.

With reference to FIG. 3, the set time T1 is derived.

The set time T1 starts after the document supported by the first support tube 47 passes through the switching area 54, that is, the document detecting element D
After the SD 1 is switched from the OFF state to the ON state, the transport unit 'Ml 1 up to the center position 67 of the first transparent plate 44 provided in the first reading area 48 is rotated at a rotation peripheral speed 1. This is the time during which the downstream end Df in the conveying direction of the original document supported by the first support cylinder 47 moves, and follows the third equation.

If the rotational peripheral speed (2) of the photoreceptor 55 is set constant, the rotational peripheral speed (1) of the first support tray 47 is determined by the rotational peripheral speed (1) of the rotational peripheral speed (2) of the photoconductor 55, which is equal to The relational expression of Equation 5 is followed by the magnification Z (see Equation 4) which is the ratio of the magnitude ΔP.

According to the fifth equation, the rotational circumferential speed (1) of the first support cylinder 47 is variable depending on the magnification 2. Therefore, according to the third equation, when setting I?
? IT1 depends on the multiplication factor 2, and for each multiplication factor Z this set time TI must be reset.

However, the time corresponding to the set time Go1 can also be measured by detecting the number of pulses generated from the pulse generator E in synchronization with the rotational circumferential speed ■1 of the first support cylinder 47. Since the pulses generated by the pulse generator E are synchronized with the rotational circumferential speed (1) of the first support cylinder 47, the conveyance distance 11 is detected while the downstream end D f of the original document in the conveyance direction is conveyed. The number of pulses N1 to be generated is always constant.

This always constant set pulse number N1 is derived. 1st
The diameter of the support member 47 is R1, and the central angle of the moving path @11 is θ1.
Then, the moving distance 11 is the number of pulses generated by the pulse generator E in synchronization with the rotational peripheral speed 1 of the sixth type first support cylinder 47, and the pulses generated during one rotation of the first support cylinder 47. If the number is NO, then the minute distance Δr that the outer circumferential surface of the first support cylinder 47 moves in one pulse follows the seventh equation.

According to Equation 6 and Equation 7, the set number of pulses N1 generated from the pulse generator while the downstream end Df in the conveyance direction of the original document is conveyed by the conveyance portion ml1 is determined by the Equation 8 detection element DSD from the OFF state to the ON state. After switching to the state and counting the set number of pulses N1 derived from equation 8 by the counter C, the downstream end Df of the original document conveyance direction is always at the first
At the center position 67 of the first transparent plate 44 in the reading area 48, a first
This is reached regardless of the peripheral rotational speed (1) of the support cylinder 47, and an electrostatic latent image begins to be formed in the exposure area 70 of the photoreceptor 55.

Note that the rotational circumferential speed of the second support cylinder 49 is the same as the rotational circumferential speed (1) of the first support cylinder 47.

Therefore, by setting the position of the detection element DSD2,
After the detection element DSD2 is switched from the OFF state to the ON state, the downstream end Df of the original document in the conveyance direction is located in the second reading area 5.
The set number of pulses indicating the time required to reach the center position of the second transparent plate 45 at zero can be derived in the same manner as the set number of pulses N1 for the first support tube 47 described above.

On the other hand, the set time T2 is a period in which the registration roller drive clutch Psc is turned off to start driving the registration rollers 83 that transport the copy paper P after the electrostatic latent image begins to be formed on the exposure area 70 on the photoreceptor 55. This is the time it takes to switch from the off state to the off state.

This set time T2 is derived with reference to FIG.

If the diameter of the photoreceptor 55 is R2, and the center angle of the moving distance 12 in which the electrostatic latent image formed from the exposure area 7o is visualized as a toner image and moves to the transfer area 78 is θ2, then the moving path Ml 2 follows Equation 9.

Since the rotational circumferential speed 2 of the photoreceptor 55 is always set constant, the time T4 required for the moving path 1liI12 is always constant regardless of the magnification 2 of the copying machine according to equation 10.

On the other hand, the conveyance distance of the copy paper P from the registration roller 83 to the transfer area 78 on the photoreceptor 55! 3, the conveyance time T5 during which the copy paper P is conveyed is the 11th time since the rotational circumferential speed of the registration roller 83 is the same as the rotational circumferential speed (2) of the photoreceptor 55.
Follow the formula.

Further, a delay time ΔT5 is required as a delay from when the clutch PSC is switched from the off state to the on state until the registration roller 83 is completely rotated at the rotational circumferential speed 2. Therefore, the time T50 from when the clutch PSC is switched from the OFF state to the ON state until the registration roller 83 is driven and the copy paper P is conveyed to the transfer area 78 follows Equation 12.

T50=T5←ΔT5... (12) The set time T2 is the lag time T4 during which the electrostatic latent image formed in the exposure area 70 is visualized as a toner image and is conveyed to the transfer area 78, It can be derived according to the relationship of Equation 13 using the transport time T50 from when the clutch PSC is switched from the off state to the on state until the copy paper P is transported to the transfer area 78.

T2=T4-T2O... (13) This set time T2 is always constant regardless of the magnification Z of the copying machine, so it can be set in advance.

Therefore, after the document detection element DSD was switched from the OFF state to the ON state by the document conveyed to the support cylinder, the counter C counted the set number of pulses N1, and then the timer T measured the set time T2. Later, copy paper P
When the registration roller driving clutch PSC, which drives the registration rollers 83 that convey the image, is switched from an OFF state to an OFF state, a transfer area 78 on the photoreceptor 5 is formed on the outer peripheral surface of the photoreceptor 55 and corresponds to the surface of the original document. The downstream end in the moving direction of the toner image being transferred matches the downstream end Pf in the transporting direction of the copy paper P being transported, and the toner image is reliably transferred to the copy paper P. This set number of pulses N1 can be set depending on the position of the detection element DSD in each support cylinder,
Further, the set time T2 is always the same. Therefore, the set pulse number N1 and setting time qT2 do not need to be reset in accordance with the magnification 2 of the copying machine, and can be set and determined in advance.

If the above-mentioned measuring means is used, even if the original document is arbitrarily supported on the support cylinder and the reading exposure operation is performed in the reading area,
The timing at which the toner image formed on the photoreceptor is reliably transferred onto the copy paper P can be controlled.

C1 Operation Below, the operation of this embodiment will be explained using timing charts and flowcharts. FIG. 5 is a timing chart for explaining the operation of the automatic document feeding type copying machine 40 of the present invention. The original document in the RDH 42 is set to perform a reading exposure operation only in the first reading area 48, and to only pass through the second reading area 50 without being read. No. 51121 (1) is connected to a drive circuit that rotationally drives each support tube 47.49, and generates a pulse from a pulse generator E in synchronization with the rotation peripheral speed ■1 of each support tube 47.49, and No. 51J ( 2) shows the off/on state of the document detection element DSD, FIG.
4) is a timer T that measures a predetermined setting time T2.
measurement state, the fifth [ff1 (5) is the registration roller 83
Registration roller drive clutch PSC to drive the
5 (6) shows the off/on state of the registration roller 83.
Timing chart I showing the on/off state of the copy paper detection element MS that detects the withdrawal position of the copy paper P fed to the
It is.

The original document is supported and conveyed by the first support tube 47, and the switching area 54 on the outer peripheral surface of the first support tube 47, which is provided with the document detection element DSD in the vicinity, is set to the downstream end Df in the conveyance direction of the document document.
When To passes, the document detection element DSD switches from the off state to the on state (time To). When the document detection element DSD is switched on, the counter C generates a pulse 7. %
The pulse emitted from E starts counting the set number of pulses N1 corresponding to the set time T1. When ill t
1, after the counter C finishes counting the set number of pulses N1, the counter C counts up and stops.

At this time t1, the downstream end Df of the original document in the conveying direction is at the first
The center position 67 of the transparent plate 44 is reached, and the reading exposure does not move Y.
starts.

From time t1 when counter C counts up, timer T
Measurement of the set time T2 is started. At time t2, timer T finishes measuring the set time T2, and this timer T stops. At this time t2, the registration roller drive clutch PSC is switched from the off state to the on state, the drive of the registration rollers 83 starts, and the conveyance of the copy paper P onto the photoreceptor 55 starts. By starting conveyance of the copy paper P at this timing, in the transfer area 78, the downstream end in the moving direction of the toner image formed on the photoreceptor 55 and corresponding to the surface of the document sheet and the conveyance of the copy paper P The downstream ends Pf in the conveyance direction coincide, and the toner image is reliably transferred onto the copy paper P.

At time t3 before time t2, the copy paper detection element MS provided near the registration rollers 83 is switched from the off state to the on state, and the copy paper P is being conveyed to the registration rollers 83. If the copy paper detection element MS is not turned on by one time t2 when the copy paper P must be detected, the copy paper P cannot be transported even though it is the timing to transport the copy paper P.

Therefore, since the copying operation cannot be performed, other processing such as temporarily stopping the electrical system of the copying machine is performed.

The time T6 from time t3 to time t2 is an arbitrary time.

The document detection element DSD, which detects the conveyance position of the document tray, switches from the OFF state to the ON state at time to, and then
The on state is continued until time t4 when the upstream end Dr of the original in the conveyance direction passes through the switching area 54, and at time t4 it is switched to the off state.

Further, the copy paper detection element MS is switched from the off state to the on state at time t3, and then the copy paper detection element MS is switched from the off state to the on state at time t5.
The on state continues until the upstream end Pr in the conveying direction passes, and the on state is switched to the off state at time t5. There is some conveyance distance left for the copy paper P from the copy paper detection element MS to the position of the registration roller 83, so that at time t
After the clutch PSC is switched to the off state at step 5,
After a preliminary time T7 for the copy paper P to reliably pass through the registration rollers 83 has elapsed, the clutch PSC is switched from the OFF state to the OFF state at time t6, and the rotational drive of the registration rollers 83 is stopped.

At time t4, the document detection element DSD, which has been switched from the on state to the off state, waits in the off state in order to detect the downstream end Df in the conveying direction of the subsequently conveyed document. Therefore, after the time variation f t 4, at any time t7
At this point, the second document sensor turns on the document detection element DSD, and the counter C and timer T measure the set time again. This time t7 is arbitrary, and there is no problem even if the registration roller 83, which is conveying the copy paper, is in the middle of a stopped state in order to copy the front surface of the document paper that has been conveyed first, i.e. There is no need to keep the document to be continuously conveyed on standby until the registration rollers 83 stop. After the document detection element DSD is turned on at least at time t7, the counter C
The time t8 when the set pulse number N1 and the set time T2 are measured by the timer T is the previous copy paper P.
It is sufficient if it is raining at time t 69J when the conveyance is finished. Therefore, according to the above-mentioned timing, even if the document is arbitrarily supported on the first support cylinder 47 and conveyed, the five-light body 55
It is possible to control the timing of upward transport.

FIG. 6 is a flowchart for explaining a program for controlling the operation of the automatic document feeding type copying machine 4° of the present invention. The original document in the RDH 42 is set to perform a reading operation only in the first reading area 48 and only pass through the second reading area 50 without being read. In this embodiment, the number of originals to be copied is set to 10. The program is structured as shown in Figure 6 (1) and (2), and from a certain step in Figure 6 (1), the program in Figure 6 (2) runs in parallel with the program in Figure 6 (1). and start processing.

First, when the program shown in FIG. 6(1) is started, in step s1, a variable X representing the number of original sheets being copied is set to "1". In step s2, the document detection element DSD, which detects the conveyance position of the document on the first support cylinder 47, is turned off, and in step S3, the copy paper detection detects the conveyance position of the copy paper P being conveyed by the registration rollers 831. setting the element MS to the OFF state, and setting the registration roller drive clutch PSC that rotationally drives the registration roller 83 to the OFF state in step S4;
Proceed to step s5.

In step S5, the switching area 54 on the first support tube 47
It is determined whether the detection element DSD has been switched from the OFF state to the ON state by passing the downstream end Df of the original document in the conveying direction. If the original has not yet been conveyed and the detection element DSD is still in the OFF state, the process of step s5 is repeated again, and the downstream end Df of the original in the conveyance direction passes through the switching area 54 and the detection element DSD is turned off. When switched to the on state, the process advances to step S6. At the same time as the process advances to step S6, a program shown in FIG. 6(2), which will be described later, starts.

In step S6, it is determined whether the detection element DSD has been switched from the on state to the off state by passing the upstream end Dr of the original document in the conveying direction through the switching area 54 on the first support cylinder 47. If the original is still being transported through the switching area 54 and the detection element DSD is in the on state, the process of step S6 is repeated again, and the upstream end D of the original in the transport direction is
When r passes through the switching region 54, the detection element DS
When D is switched from the on state to the off state, the process advances to step s7.

In step S7, the number of originals transported to the first support cylinder 47 for copying and passing the position where the detection element DSD is set reaches the total number of originals to be copied (10 in this embodiment). It is decided whether or not it was done. step s
1, the value of the variable X representing the number of sheets of originals being copied is set to "1", so the process advances from step s7 to step S8. In step S8, the value of variable X is incremented and the process proceeds to step B 5 /\. Thereafter, the processes from step 55 to step S8 are repeated, and when the value of variable X reaches the total number of copies to be made in step s7, this program ends.

When the detection element DSD is turned on in step s5 in the program of FIG. 6(1), the process proceeds to step s6 and the program of FIG. 6(2) starts. When the program starts, in step m1, the counter C that counts the set number of pulses N1 generated from the pulse generator E is set to the initial value rOJ, and in step [r1
2, the timer T that measures the set time T2 is set to the initial value "
0”. In step m3, counter C
starts counting, and proceeds to step m4.

In step m4, it is determined whether the count value of the counter C has reached the set number of pulses N1. still counter C
If the count value of has not reached the set pulse number N1,
The process of step rn4 is repeated again, and when the count value of the counter C reaches the value of the set number of pulses Nl, the process proceeds to step m5/\. Counter C ends counting in step r""5, and timer T ends counting in step r""5.
starts measuring the set time T2, and proceeds to step m7.

In step m7, it is determined whether the time measured by the timer T has reached the set time T2. If the time measured by timer T has not yet reached the set time T2, step r is executed again.
17 is repeated, and when the time measured by the timer T reaches the set time T2, the process proceeds to step rn8. In step m8, it is detected whether or not the copy paper P has been conveyed near the registration rollers 83. It is determined whether or not the copy paper detection element MS has been switched from the off state to the on state.The copy paper P has not yet been conveyed near the registration roller 83, and the detection element MS is in the off state. Then, proceed from step m8 to step rri9 /\.

In step m9, in order to transfer the toner image formed on the photoconductor 55 corresponding to the surface of the document tray onto the copy paper P in the transfer area 78 on the photoconductor 55, the registration rollers 83 that convey the copy paper P are moved. This indicates that the copy paper P has not been conveyed to the registration rollers 83 even though it is the timing to start the rotational drive. Therefore, processing such as temporarily stopping the electrical system in the body 41 of the copying machine and stopping the copying operation is performed.

If the copy paper P has already been conveyed near the registration roller 83 in step rn8 and the detection element MS has been turned on, the process advances to step rn10. In step mlO, in order to start rotationally driving the registration roller 83, the registration roller driving clutch PSC is used.
from the off state to the on state, step rn11
Proceed to.

In step mll, the conveyance of the copy paper P by the registration roller 83 is nearing completion, the upstream end Pr of the copy paper P in the conveyance direction passes the position of the detection element MS, and the detection element MS is switched from the on state to the off state. It is determined whether or not. If the detection element MS is in the ON state because the copy paper P is still being conveyed, the process of step mll is repeated again, and the upstream end Pr of the copy paper P in the conveyance direction passes the position of the detection element MS, and the detection element MS is turned on. When the MS is switched from the on state to the off state, the process advances to step m12. In step rn12, after the preliminary time T1 during which the upstream end Pr of the copy paper P in the conveyance direction has been conveyed over the conveyance distance from the position of the detection element MS to the position of the registration rollers 83, a clutch that controls the rotational drive of the registration rollers 83 has elapsed. The PSC is switched from the OFF state to the OFF state, the rotational drive of the registration roller 83 is stopped, and this program is ended.

Even if the first support cylinder 47 arbitrarily supports the document tray and performs the reading exposure operation according to the above-mentioned program, in the transfer area 78, the reading exposure operation causes the image to be placed on the photoreceptor 55 corresponding to the surface of the document tray. Copying is performed so that the downstream end in the moving direction of the toner image in which the formed electrostatic latent image is visualized matches the downstream end Pf in the conveying direction of the copy paper P, and the toner image is reliably transferred onto the copy paper. It is possible to control the conveyance of paper P.

In this embodiment, a set pulse number N1 counted by a counter C and a timer T are used to match the downstream end of the toner image in the moving direction and the downstream end of the transported copy paper in the transport direction in the transfer area on the photoreceptor. The set time T2 measured by is set constant. This set number of pulses N1
By resetting the set time T2 to various values, it is possible to move the transfer position of the toner image onto the copy paper in the transport direction.

In this embodiment, in order to measure the set time, the counter C
and timer T are used. However, in another embodiment, the counter C may not be used and the timer T alone may be used. That is, the time T1 for measuring the set number of pulses N1 by the counter C is reset according to the magnification Z during each copying operation, and the set time T2 is further taken into account.
By setting the set time T3 according to the second equation as the set time measured by the timer T, the same operation as in this embodiment can be performed.

Further, in this embodiment, a pulse generator that generates pulses synchronized with the support tube is connected to a drive circuit that rotationally drives the support tube. As another example, it may be advantageously implemented by forming a gear-like shape on the outer peripheral surface of the support tube and measuring the number of teeth of the gear as the support tube rotates using a rotary encoder or the like attached to the periphery of the support tube. can do.

Furthermore, in this embodiment, a reflective photodetector element is used as the detection element DSD for detecting the moving position of the document on the support tube. As other embodiments, a transmission type photodetection element, a mechanical type detection element, etc. are used. The transmission type detection element is, for example, a light emitting element such as an LED that is fixed inside the support tube without rotation of the support tube and emits light toward the outer circumferential surface of the support tube. It can be constructed by installing a light receiving element near the surface to receive light from the light emitting element. The mechanical detection element has a claw-like part that is in contact with the outer peripheral surface of the support tube, and the claw-like part is displaced as the document passes through it.This TII structure also allows the detection of the original. It can be advantageously implemented in detecting a moving position.

Further, in this embodiment, the original is conveyed by a circulation type automatic original feeding device. As another example, instead of using a circulating system, a starting document storage section is provided on one side of the reading area to feed the original into the reading area, and an end document storing section is provided on the other side to store the original that has passed through the reading area. A document storage section is provided for transporting the document from one side to the other, and the reading operation is carried out between the two sides.
This can also be carried out advantageously by using a transport type automatic document feeder or the like that performs a 100% transfer.

Effects of the Invention According to the present invention, even if a document is read at an arbitrary timing, a predetermined set time is measured after the detection means for detecting at least the leading edge of the document along the conveyance direction generates a detection signal. This makes it possible to control the timing at which an image corresponding to the surface of the document read on the photoreceptor is transferred onto copy paper. By arbitrarily performing the reading exposure operation of the original, it becomes possible to perform the reading exposure operation continuously without having to wait for the original in front of the reading area. Therefore, the time required to transport the original to the reading area can be significantly reduced, and the time required for copying multiple sheets of original in the copying machine can also be shortened, improving the performance of the copying machine. .

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view of an automatic document feeding type copying machine 40 which is an embodiment of the present invention, and FIG. 2 is a document detection element DSD.
3 is a simplified sectional view of the first support tube 47 and its surroundings, and FIG. 4 is a simplified sectional view of the photoreceptor 55 and the registration roller 83. ,
FIG. 5 is a timing chart for explaining the operation of the automatic document feeding type copying machine 40 of the present invention, and FIG. 6 is a flowchart for explaining the program for controlling the operation of the automatic document feeding type copying machine 40 of the present invention. , FIG. 7 is a simplified cross-sectional view of the conventional automatic document feeding type copying machine 1, and No. 8 [2! 1 is a perspective view of a photoreceptor 7. FIG. 40... Automatic document feeding type copying machine, 42... Circulation type automatic document feeding device (RDH), 47... First support cylinder, four... Second support cylinder, 55... Photoreceptor, 56...Optical system, 66...Exposure lamp, 83...Registration roller, D...Document, Df...Downstream end in the conveying direction of document, P...
...Copy paper, DSD...Document detection element, MS...Copy paper detection element, PSC...Registration roller drive clutch, C...Counter, T...Timer, E...Pulse generator , N1... set pulse number, Tl, T2. T3・
・・Setting time agent Patent attorney Number of strokes

Claims (1)

[Scope of Claims] A copying machine that optically scans the original while supporting the original on a supporting means and rotating the supporting means in the transporting direction of the original, the original being supported by the supporting means along the transporting direction. a detection means for detecting at least the leading edge; a signal generation means for generating a clock signal in synchronization with the document conveyance speed by the support means; and a signal generation means for receiving the clock signal from the signal generation means to measure a predetermined set time. and a clock means, after the detection signal is generated from the detection means, the set time is measured by the clock means based on the clock signal of the signal generation means, and then conveyance of the copy paper is started. Features: Automatic document feeding type copying machine.