JPH03174555A - Automatic document feeding device - Google Patents

Abstract

PURPOSE:To make a document carrying speed low and to improve stabilization in separating performance by low-speed loosening at the time of feeding a document by fixing the specified interval between documents and the length of a carrying path in the case of the document having the smallest size in a feeding direction. CONSTITUTION:The feeder is constituted of a document feeding part 10 for feeding one document D from a bundle of documents to a document platen glass 2, a carrying part 20 for carrying the fed document to a specified position on the glass 2, a document carrying-out part 30 for ejecting the document fed from the document carrying part 20 to a paper ejecting tray 39 after finishing the exposure of an image. In the case of the document having the smallest size in the feeding direction, the interval between the documents and the length of the carrying path are fixed so that an (N-1)th document Dn+1 which has been exposed before the exposure of an Nth document Dn+2 is stopped in the carrying path and an (N-2)th document Dn is completed to be ejected while the Nth document Dn+2 is being exposed. Thus, the document carrying speed is made low and the stabilization of the document separating performance is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement in an automatic document feeder in a recording device such as an electrophotographic copying machine, and more specifically, to adjust the timing of document ejection according to each document size. The present invention relates to an automatic document feeder that automatically adjusts the operation of ejecting the document in conjunction with the exposure and efficiently performs the operation of discharging the document.

[Conventional technology]

The automatic document feeder (hereinafter referred to as ADF) of a copying machine is a device that automatically transports the original set on the original tray to the original table, has the copying machine make copies, and then outputs it onto the output tray. It is. This device is suitable for high-speed copying of a large number of sheet originals. Furthermore, especially in recent copying machines, in order to improve copying performance, the copying speed has been increased, and accordingly, the document conveyance speed of the ADF has also been increased (approximately 1000 to 1200 mm/5ea).

In addition, documents are fed and ejected in a timely and efficient manner.
opm (number of original sheets fed per minute in ADF) and c p
It is conceivable to improve copy productivity, which is the ratio of the number of copies per minute in a copying machine. As a conventional example of these, Japanese Patent Application Laid-Open No. 6247636 (Conventional Example 1) discloses that two originals are automatically sent out sequentially on a document table, each original is conveyed for a set time by a detection means, and the individual originals are conveyed for a predetermined time. This is a method of aligning it with the mounting position. Furthermore, Japanese Patent Application Laid-Open No. 60-36236 (Conventional Example 2) discloses a method in which the trailing edge of the transported document is stopped by aligning it with the document stop position, and paper feeding is started before the discharged document reaches the discharge roller. Moreover, when the next fed document stops at the reference position, the trailing edge of the discharged document can reach the discharge roller.
It is disclosed that it is possible to speed up the supply and discharge processing. Furthermore, in Japanese Patent Application Laid-Open No. 61-32836 (Conventional Example 3), originals of various sizes are conveyed sequentially to a standby position at appropriate intervals, and after the exposure of the previous original is completed, each original is This system simultaneously transports the originals and moves the next waiting original to the copying position. Regardless of the size of the original, the originals can be transported sequentially with the minimum amount of travel of the transport belt, making it efficient. It is disclosed that copying work is possible.

The operation of exchanging originals on the original platen glass using these conventional ADFs is as follows: (1) After a paper ejection sensor detects that the original on the original platen has been ejected, the next original is sent out from the stack section and then stopped.

■A method in which the previous document is ejected before the conveyance belt that transports the document stops (the document is fed).

■A method of switching back the document feeding path on the glass surface of the document table, and passing the next document onto the glass surface while the previous document is being ejected from the glass surface.

etc. are known.

However, in ■ and ■, the above-mentioned copy productivity o
Increasing pm/cpm has some drawbacks in terms of functionality.
Regarding this, if we assume that the copying machine is currently copying 45 sheets per minute, the drum linear speed is currently 260 mm/sea, and the transport linear speed is calculated with the goal of 100% copy productivity, (I) the time required to copy one sheet. is 60/45 = 1.33
3 seconds, and (II) exposure time (as A4 size) is 210mm/26
0mm= 0.808sec (l[[) Possible conveyance time-1,333-0,808=
0.525sec However, i [Length of stacking glass 450m
Let it be m.

■The distance from the end surface of the glass to the outlet is 240 mm.

(TV) Conveyance speed - (450mm+240mm)10.
525 = 1.314 m/s Therefore, the speed is 1.3 m without considering the allowance for starting and stopping the motor rotation, switching back the document, etc.
It can be seen that a high linear velocity of /sec or higher is required. Although the speed of copying machines has increased recently, this speed is 1.0 to 1.
Even considering that it is about 2 m/sec, it can be said that the speed is quite high.

However, increasing the document conveyance speed causes various problems such as an increase in the size of the motor, an increase in power consumption, an increase in the degree of document damage, and a decrease in document separation performance.

Regarding case (■), the copy productivity is high, but the two originals A and B are misaligned between the original platen glass and the conveyor belt. In other words, when the Ai original is ejected, the BW original is inserted. This method is considered to have the drawbacks of folded originals and the possibility of paper jams. Furthermore, since the A document is ejected during exposure after inserting the Bi document, a clutch that turns off only the drive of the conveyance belt or a dedicated conveyance belt motor is required, which is disadvantageous in that it is expensive.

[Problem to be solved by the invention]

As mentioned above, we provide an ADF that has high copying productivity without particularly increasing the document transport speed, can be done with a single motor, and is not particularly prone to jamming even with folded documents. It is something to do.

[Means to solve the problem]

The present invention aims to solve the above-mentioned problems in automatic document feeders and to increase the number of copies processed.

An automatic document feeder of the present invention that achieves the above object sequentially transports a plurality of sheet-like documents to an image exposure section, stops the documents at the image exposure section, and performs scanning exposure by moving an optical system. In an automatic document feeder that conveys the document to the document eject tray after exposure, at least in the case of the minimum size document in the feeding direction, if the Nth document is being exposed, the exposure is completed before that (N-1). ) Stop the original in the transport path, and then press (
N-2) The conveying path length of the document interval is determined so that the discharge of the th document is completed.

Also, the present invention provides a method for starting from the leading edge of the Nth document (N
-1) This is achieved by an automatic document feeder characterized in that the trailing edge of the th document is determined by recognizing the document size.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing the document conveyance path of the automatic document feeder according to the present invention, FIG. 2 is an external perspective view of a copying machine equipped with the automatic document feeder, and FIG. 3 is a drive system of the automatic document feeder ( Fig. 4 is a schematic diagram of the entire drive system configuration of this device, Fig. 5 is a schematic diagram of one document transport path during duplex original copying, and Fig. 6 is a time chart. . The structure and operation of the automatic document feeder will be explained with reference to these figures.

The automatic document feeder (ADF) of the present invention is shown in FIGS.
As shown in the figure, there is a document feeder lO installed on the copying machine main body 1, which feeds one document from a stack of documents placed on the document tray 11 onto the document table glass 2; 10
a transport unit 20 that transports the original fed from the original to a predetermined position (image exposure scanning position) on the original table glass 2 on the original table;
The document transport unit 30 includes a document transport unit 30 that discharges the document sent out from the document transport unit 20 onto a paper discharge tray 39 after image exposure is completed.

Now, FIGS. 3 and 4 will be explained starting from the drive system. There is a motor M as a driving source in the center, and a paper feed section 10 is on the left side.
In the center is the drive system of the transport section 20, and on the right is the drive system of the original discharge section 30. GO using motor M as the drive source.

Through each gear of Gl, the toothed pulley P1. P2 is rotated, and the original ejection section 3 is moved by the toothed belts Bl and B2, respectively.
0, the document feeding section 10, and the document feeding section 10 connects a separation belt roller 13A, a paper feeding roller 15.degree. G3゜G4. G5. G
6.

The gear G6 at the end of the shaft of the roller 13A has a clutch 1 built into it, and is free except during paper feeding rotation. Similarly, the paper discharge reversing roller 31 includes gears Go, Gl and pulleys PI, P4.
P5 and gear G7. Driven through G9, and also driven by gear G9
2 is installed in the one-way clutch, and gear G7 is installed in the one-way clutch 3. As a result, belt B1. B
2 rotate in the direction of the arrow shown.

Regarding the schematic diagram in FIG. 5, the automatic document feeder of the present invention has the feature that it can also make double-sided copies of double-sided documents, and the document feeder passes through the same conveyance path as normal single-sided copying and
When surface exposure (copying) is completed, arrow S1. The paper takes the path S2, is not ejected even after passing through the ejection reversing roller 31 and the pinch rollers 32 and 33, and is inverted and conveyed.Then it takes the path shown by arrows R1 and R2, and is placed on the original platen glass again for second side exposure (reverse side copying). 2
It is exposed (copied) to the paper, takes the path of arrows SL and S2 again, and this time passes through the paper ejection reversing roller 3L, pinch rollers 32, 33, and the path of arrow S3 to the paper ejection roller 35.
This shows the state in which the paper is ejected onto the paper ejection tray 39.

Further, FIG. 6 shows a time chart of the document feeding and conveying process of this apparatus, which is similar to the above-mentioned FIG. 1.

This diagram shows the operation details explained in Figures 3 and 4 over time, and shows the document size detection sensor, ejection detection sensor, drive motor, timer, paper feed clutch, etc. on the left vertically and horizontally. By pressing the ADF start signal (copy button) on the operating element and the right mechanism, copying starts from the first document (Dnth sheet), and then (Dnth sheet).
+1st sheet) and (D n + '; 1st sheet) are graphed over time to show how the aforementioned operating elements respond to the progress of copying. Now, regarding this, we will add the above-mentioned figures 1, 2 and 3,
This will be explained in detail.

Now, a document tray 11 is set on the document tray 11, which is installed so as to protrude from the left side of the copying machine main body l. This document can be copied by pressing the copy button (not shown).
The paper feed solenoid SDI is activated, and the movable guide plate 12 is raised to press the document sheet against the handling belt 13. Next, by driving the motor M, the handling belt 13 is moved to the roller 1.
3A starts rotating in the direction of the arrow connected to the drive source, and in cooperation with the stop roller 14, the topmost document D is rotated.
Only n is sent out. When the leading edge of the document tray reaches the nip exit of the paper feed roller 15 rotating in the direction of the arrow, the detection signal from the document size sensor PS1 turns off the paper feed clutch 1, and the driving force transmission of the handling belt 13 is stopped. After it is cut off, it rotates freely, but the preceding manuscript D
Only paper n is conveyed by the paper feed roller 15.

The document Dn conveyed by the paper feed roller 15 passes above the stopper plate 3 that positions the rear end of the document Dn, and then passes between the document table glass 2 installed on the top surface of the copying apparatus main body 1 and the document conveyance section 20. reaches the pressure contact position of the conveyor belt 21, and is further conveyed by the frictional force of the rotating conveyor belt 21. The conveyor belt 21 is stretched between a rotatable drive roller 23 and a driven roller 24 on bearing plates fixed to both side walls of the housing 22, and can be rotated forward and backward by a motor M.

The lower running surface of the conveyor belt 21 includes pressure rollers 25, 26,
It is pressed against the two sides of the document table glass by angles 27° and 28. When the size of the document Dn is automatically detected by the leading and trailing edges of the document Dn passing the document size detection sensor PSl, the motor M changes from normal rotation to reverse rotation.
The document Dn that has gone too far is moved backward and the trailing edge of the document is stopped by the stopper plate 3.
It hits and stops moving. Thereafter, exposure (copying) is performed by optical scanning within the copying machine main body l. After the exposure is completed, the motor M is turned on, the paper discharge reversing roller 31 rotates, the document Dn is conveyed, and the document Dn is stopped at a position in front of the document table glass 2 and the paper discharge roller 35. Document D that then stops
The next document Dn+1 is conveyed by turning on the paper feed clutch 1 so as to keep the distance from the document size detection sensor PS1.
When the document D is reached, the paper feed clutch Kl is turned off, the document length is detected, and the handling belt 13 is released, but the document D
n+1 is transported to the optical scanning position. Furthermore, manuscript D
When the optical scan of document n+1 is completed (copying is completed), the document D is conveyed to the document discharge section 30, and the document D that was previously conveyed and stopped.
n is transported, and the rear end is the document ejection detection sensor PS2
When the installation location is reached, a suction timer starts so that the discharge section solenoid SD2 performs the suction operation, and at the same time the discharge section solenoid SD2 turns ON, the paper discharge roller 35 is rotated, the document Dn is clamped, and the paper discharge roller 35 is rotated. 3
5 shows the progress of paper ejection. These manuscripts Dn,
Dn+l and next manuscript Dfi+2. The movement of Dn+3 is shown in FIGS. 7 and 8. In addition, in the present invention, the exposure of the final document (
Even after copying is completed, it is necessary to drive the motor M until the two originals are ejected due to the above-mentioned content.

Note that when the interval between each document is b1 and the length of the document is L,
The dimensional relationship between these is 2 L + b<A<2 L+2b
It is desirable to do so. However, the conveyance path A is the distance from the stopper plate 3 to the paper discharge roller 35, as shown in the schematic diagram of FIG.

■With the current dimensions (2L+b), A = 450mm (W stacking table glass length), and discharge Wk path length - 240mm, then b = 450mm +
240mm - 210mm (A4 size) x 2゛, therefore b = 270mm (interval). If the circumferential speed of the photosensitive drum is normally 0.525 seconds,
The conveyance speed of the original is 270 mm + 210 mm (A4 size) / 0.525 sec" = 914 mm/sec.

However, in this case, if we do not take into account the rise and fall of the motor, the conventional speed is 1.314n++n/
Since it is at S position, it can be lowered to 914mm/S. This relationship (2L+b) is shown in FIG.

■Furthermore, with the dimension (2L+2b), b = 135m
m, and the conveyance speed of the document is 135 mm + 21
0mm (A4 size) / 0.525' = 657mm
/S, and can be made. This (2L+2b
) is shown in Figure 10. By providing the above-mentioned relationship (■), it is possible to reduce the conveyance speed of the document, which is a great advantage in terms of functional performance as will be described later. Also, if A is within the range of the above formula, it means that during optical scanning (W optical copying), the leading edge of the preceding document is
It is necessary to prevent the unsightly protrusion from being pushed out.

In addition, the document size detection sensor PS1 recognizes the document size.
In addition to this method, a document width regulating plate may be provided on the document tray 11, and the amount of movement of this plate during setup may be detected by a sensor to recognize the document size of the document type. Alternatively, the document size may be manually determined. The key may be memorized manually.

〔Effect of the invention〕

As described above, according to the automatic document feeder of the present invention, it is possible not only to reduce the document feed speed, but also to stabilize and improve separation performance and smooth document feed by performing low-speed separation during document feeding. This is effective in preventing damage to the leading edge of the document. In addition, it is possible to reduce the load on the motor, save power consumption, and install a small, low-torque motor. Furthermore, if the speed is not reduced, it is possible to improve the copy productivity O pm / C pm.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the document conveyance path of the automatic document feeder according to the present invention, FIG. 2 is an external perspective view of a copying machine equipped with the automatic document feeder, and FIG. 3 is a drive system of the automatic document feeder ( Fig. 4 is a schematic diagram of the overall drive system configuration of this device, Fig. 5 is a schematic diagram of the document transport path during double-sided original copying, and Fig. 6 is a schematic diagram of the document transport path of this device. 7 and 8 are schematic diagrams showing the document conveyance process of the present apparatus, and FIGS. 9 and 10 are schematic diagrams illustrating the document interval dimension conditions of the present apparatus. l...Copy machine body 2...Original table glass 3...
- Stopper plate 10...Paper feed section 11...Document tray 12...Movable guide plate 13...Sorting belt 15...Paper feed roller 20...Transportation section
21... Conveyor belt 23... Drive roller
24...Followed roller 30...Document discharge section 31
...Paper discharge reversing roller 32.33...Pinch roller
34... Pressure lever 35... Paper ejection roller D.
・・Document G1~GIO・・Gear Kl・・2. 3...One-way clutch M...Motor P1 to P7...Drive pulley PSl...Document size detection sensor PS2...Document discharge detection sensor SDI...Paper feed solenoid Sn2. Sn2... Discharge unit solenoid S... Forward arrow b for double-sided originals... Spacing R... Return arrow L for double-sided originals... Length of original

Claims (2)

[Claims] (1) Multiple sheets of originals are sequentially conveyed to the image exposure unit, the originals are stopped at the image exposure unit, the optical system is moved to perform scanning exposure, and after exposure, the originals are transported to the original output tray. In an automatic document feeder that uses an automatic document feeder, at least in the case of the minimum size document in the feeding direction, while the Nth document is being exposed, the (N-1)th document, which has been exposed previously, is stopped in the transport path. , (N-2) The automatic document feeder is characterized in that the document interval and the conveyance path length are determined so that the (N-2)th document has been completely discharged. (2) The automatic document feeder according to claim 1, wherein the trailing edge of the (N-1)th document from the leading edge of the Nth document is determined by recognizing the document size. .