JP2003252479A - Paper conveying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent unpleasant sound generated by a paper feeder. <P>SOLUTION: This paper conveying device is provided with paper feed rollers 14, 22 receiving and conveying paper, and a registration roller pair 16 conveying the paper conveyed from the paper feed rollers 14, 22. After the paper is butted on the registration roller pair 16 to be bent, conveyance of the paper is restarted at a prescribed timing. Guide members 40, 43 are provided at the deflection formation part of the paper. The guide members 40, 43 are provided with a plurality of elastic Mylar sheets 41, 42, 44, 45, and tip ends of the Mylar sheets 42, 45 contact with bellies of the Mylar sheets 41, 44 at a prescribed angle. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device applied to electrophotographic copying machines, printers, facsimiles and the like.

[0002]

2. Description of the Related Art In an image forming section of an image forming apparatus such as an electrophotographic copying machine, a printer or a facsimile machine,
After the toner image formed on the photoconductor is transferred onto the transfer paper by the transfer device, the toner image is fixed and discharged to the outside of the apparatus. For example, as shown in FIG. 18, the transfer paper is fed from a paper feed tray, passes through the paper feed rollers 101 and 103, and is temporarily stopped with the leading end abutting against the registration roller pair 105 in front of the transfer device, The registration roller pair 105 is driven in synchronization with the timing of the toner image on the photoconductor 107 to feed the transfer paper to the transfer position.

However, the collision sound when the front end of the transfer paper hits the registration roller pair is very annoying. For example, in Patent Document 1, the speed at which the transfer paper collides with the registration roller pair is slowed down and stopped. The noise generated when the transfer paper collides with the pair of registration rollers is reduced.

Further, a noise is generated when the transfer sheet is driven by the pair of registration rollers and is conveyed to the image forming section while being driven. That is, FIGS.
As shown in 0, the driving of the paper feed roller pair that grips the trailing edge of the transfer paper is sequentially stopped in order to prevent double feeding of the paper. There was a sound when was suddenly extended.

[0005]

[Patent Document 1] Japanese Unexamined Patent Publication No. 9-175693

[0006]

Further, when the pair of registration rollers and the roller gripping the transfer paper are simultaneously driven when the transfer paper is re-conveyed, it is possible to prevent the paper from being abruptly stretched. For efficiency, the roller gripping the transfer paper rotates faster than the rotation speed of the registration roller, and even if it is driven to rotate at the same time, the trailing edge of the transfer paper is conveyed faster. There was a problem that the deflection increased and it became a jam.

An object of the present invention is to prevent an unpleasant sound generated from a paper feeding device.

[0008]

According to a first aspect of the present invention, there is provided a sheet feeding means for accommodating a sheet and conveying the sheet, and a registration roller adjusting means for conveying the sheet conveyed from the sheet feeding means. In a paper transporting device that abuts a sheet against the registration roller adjusting means to give it a bend, and then starts the transport of the sheet again at a predetermined timing, a buffering means is provided at the bend forming portion of the sheet, and a plurality of buffering means are provided. The elastic sheet member is provided, and the leading end of one sheet member is in contact with the antinode of the other sheet member at a predetermined angle.

According to the first aspect of the invention, the sheet conveyed from the sheet feeding means is conveyed to the registration roller adjusting means while being assisted by the conveyance assisting roller. The sheet hits the registration roller adjusting means and is bent. At this time, the flexible portion of the sheet hits the cushioning means of the deflection forming portion, and the two sheet members of the cushioning means bulge outward. In this way, the sheet member is deformed along with the bending of the sheet to gradually disperse the bending force of the sheet, so that it is possible to suppress the instantaneous buckling of the sheet without instantaneous bending. It is possible to reduce the occurrence of the collision sound.

According to a second aspect of the present invention, in the sheet conveying apparatus according to the first aspect, there is provided registration roller adjusting means for conveying the sheet conveyed from the detachable paper feed tray, and the registration roller adjusting means. In a paper transporting device that starts transporting paper again at a predetermined timing after hitting the paper with a certain amount of flexure, if the optional device is not used, the sound insulation means is provided at the attachment / detachment port for removing the optional device. It is characterized by

According to the invention of claim 2, claim 1
In addition to the same effect as the invention described in (1), the sound insulation means is provided at the attachment / detachment port, so that when the optional device is not used, the attachment / detachment port is opened and the sheet abuts the registration roller adjusting means from this opening. It is possible to prevent sound and sound from leaking when the paper flexes.

According to a third aspect of the invention, a sheet is accommodated,
Further, a sheet feeding unit for feeding the sheet and a registration roller adjusting unit for feeding the sheet conveyed from the sheet feeding unit are provided, and the sheet is abutted against the registration roller adjusting unit to give a bend, and then at a predetermined timing. In the paper transport device that starts transporting the paper again, when the registration roller adjusting means is operated at a predetermined timing to restart the transport of the paper, the paper transport speed of the registration roller adjusting means is one upstream paper. It is characterized in that it is faster than the paper transportation speed of the transportation means.

According to the third aspect of the present invention, the sheet conveyed from the sheet feeding means is conveyed to the registration roller adjusting means. The paper hits the registration roller adjusting means,
Deflection is formed. Then, at the timing of image formation, the registration roller adjusting means is driven to convey the sheet toward the image forming unit. At the time of re-conveyance, only the registration roller adjusting means is not driven, and the rotation speed of the registration roller adjusting means is driven faster than the rotation speed of the paper feed roller on the downstream side. It will disappear as it gets older. Therefore, unlike the conventional case, the sound that the deflection is suddenly extended is not generated by driving only the registration roller adjusting means.

According to a fourth aspect of the invention, in the sheet conveying apparatus according to the third aspect, when the sheet is abutted against the registration roller adjusting means, the sheet is temporarily stopped and the sheet is re-conveyed from the registration roller adjusting means. The registration roller adjusting means and the sheet feeding means are driven in synchronization with each other, and thereafter, the driving of the sheet feeding means is stopped with the trailing edge of the sheet sandwiched by the sheet feeding means.

According to the invention described in claim 4, claim 3
In addition to the same effect as the invention described in (1), the leading end of the sheet abuts the registration roller adjusting means to form a bend. Then, at the timing of image formation, the registration roller adjusting means is driven to convey the sheet toward the image forming unit. Then, the driving of the sheet feeding unit is stopped while the trailing edge of the sheet is left in the sheet feeding unit for a predetermined length. In this way, by stopping the driving of the paper feeding means leaving the trailing edge of the paper for a predetermined length, it is possible to prevent the paper from being continuously fed.

According to a fifth aspect of the invention, in the sheet conveying apparatus according to the fourth aspect, a stop time for sandwiching the rear end of the sheet is calculated according to the sheet size, and the sheet feeding means is driven based on this stop time. It is characterized by stopping.

In the invention described in claim 5, claim 4
In addition to the same effects as the described invention, the stop time for sandwiching the trailing edge of the paper is calculated according to the paper size, and the driving of the paper feeding unit is stopped based on this stop time. Therefore, it is possible to prevent continuous feeding of the paper regardless of the size of the paper.

According to a sixth aspect of the invention, a sheet is accommodated,
In addition, the sheet feeding unit that conveys the sheet, the registration roller adjusting unit that conveys the sheet conveyed from the sheet feeding unit, and one or more relay conveying units between the sheet feeding unit and the registration roller adjusting unit are provided. In a paper transporting device that starts transporting the paper again at a predetermined timing after abutting the paper on the adjusting means to give a bend, a second drive that directly connects the registration roller adjusting means and the relay transporting means. A transmission means is provided, and when the sheet is re-conveyed from the registration roller adjusting means, the registration roller adjusting means and the relay conveying means are synchronously driven.

According to the sixth aspect of the present invention, the leading end of the sheet conveyed from the sheet feeding means strikes the registration roller adjusting means, and the sheet is bent in this state. Further, the trailing edge of the paper is in a state of being sandwiched by the relay conveyance means. Then, when the sheet is re-conveyed from the registration roller adjusting means, the relay conveying means and the registration roller adjusting means rotate in synchronization with each other by the second drive transmission means to convey the sheet to the image forming section. In this way, since the relay conveying means and the registration roller adjusting means can rotate at the same number of revolutions at the same time, it is possible to convey the paper from the registration roller conveying means while keeping the deflection, and the paper is stretched rapidly. It is possible to prevent the generated sound.

According to a seventh aspect of the present invention, in the sheet conveying apparatus according to the sixth aspect, the second drive transmission means is a one-way drive transmission means provided in either the registration roller adjusting means or the relay conveyance means. Until the paper is conveyed to the registration roller adjusting means, the second drive transmitting means idles so that the paper conveying speed of the relay conveying means rotates faster than the paper conveying speed of the registration roller adjusting means. .

According to the invention of claim 7, claim 6
In addition to the same effect as the invention described above, when the relay conveying means rotates at a relatively higher speed than the registration roller adjusting means, the one-way drive transmitting means acts to adjust the registration roller to adjust the registration roller. Not transmitted to the means. Therefore, the sheet can be conveyed at high speed until the sheet hits the registration roller adjusting means, and the image forming speed is not reduced.

According to an eighth aspect of the invention, in the sheet conveying apparatus according to the seventh aspect, the second drive transmission means transmits the driving force by the timing belt, and the one-way drive transmission means is the relay conveyance means. It is characterized in that it is provided in.

According to the eighth aspect of the present invention, the same effect as that of the seventh aspect of the invention is obtained, and the timing belt operates only when the registration roller adjusting means is driven. Since there is no noise, there is little noise.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 6 illustrates the image forming apparatus 100.
FIG. 2 is a configuration cross-sectional view showing the outline of a digital copying machine that is an embodiment of the present invention. The image forming apparatus 100 includes a main body 1 and a paper feed bank unit 2 capable of two-stage paper feed. Since the main body 1 alone has the two-stage paper feed tray, the function of the image forming apparatus 100 can be exhibited without the paper feed bank unit 2. The route indicated by the solid line arrow in FIG. 6 is the paper transport route during image formation when paper is fed from the first tray 10 of the main body 1. When feeding paper from the second-stage tray 11, the third-stage tray 12, and the fourth-stage tray 13 of the main body 1, the paper conveyance route is shown by a broken line, and no matter which tray is used, the final 1 Merge onto the same route as the tray tray 10.
FIG. 1 is a cross-sectional view of a portion of the paper feeding / conveying system of FIG. 6 (from the second tray to the photoconductor 6). In the central portion of FIG. 1, three types of transport routes A, B and C are shown.

A is a path from the first tray 10. The sheet separated by the sheet feed roller 14 and the separation pad 25 by only one sheet is detected by the registration detection 27 and abuts against the registration roller pair 16, and is subjected to the timing adjustment while forming the deflection, and then moves toward the photoconductor 6. .

B is a path from the second tray 11. The sheet separated by the sheet feeding roller 22 and the separation pad 26 by one sheet moves upward while being assisted by the conveyance assisting roller 23, and goes toward the relay roller pair 24. The sheet merges with the path A further upward while passing the relay detection 28 located at the same position as the relay roller pair 24. After that, the first tray 1
The operation is the same as that for sheets from 0.

Reference numeral C denotes a paper path when a double-sided conveyance unit (not shown) which is an external option, a large-volume paper feeding bank (not shown), and the like are installed. The exterior 31 has an opening 30 for conveying a sheet, which is provided as an external option. If no option is installed, it is left open. The paper that has been transported from the external option is
Immediately, it merges with the path A, and performs the same operation as the sheet from the first tray 10.

In this embodiment, the sound leaked from the opening 30 when the optional external device is not installed and the paper fed from the first tray 10 or the other trays 11, 12 and 13 are registered by the registration roller. The impact noise generated when the pair 16 is contacted to form a bend is reduced. When installing an external option, the opening 3
Since 0 is blocked by the option and sound leakage does not occur, it is not necessary to use this configuration.

The deflection forming section 46 for reducing the collision of the sheet fed from the first tray 10 with the registration roller pair 16.
In addition, the deflection forming unit 47 for sheets fed from other than the first tray 10 is provided. The flexure forming portion 47 is provided with resin or metal guide members 40 and 43 in the sheet conveying direction, and the guide members 40 and 43 are arranged by combining two sheets of Mylar 41, 42, 44, 45 which are elastic films. . One of the mylars 41, 44 was provided in the substantially center of the belly so that the other of the mylars 42, 45 contacted at a predetermined angle.

FIG. 2 shows the case where paper is fed from the first tray 10.
The figure which shows the shape change of the mylars 41 and 42, FIG. 3 is the figure which actually conveyed the paper from the 1st tray, FIG. 4 is the 2nd tray 1.
FIG. 5 is a diagram showing the shape change of the mylar when the sheet is fed from No. 1, and FIG. 5 is a diagram showing the sheet actually conveyed from the second tray 11. The sheet sent out from the first tray 10 passes between the sheet feeding roller 14 and the separation pad 25, and the leading edge of the sheet hits the registration roller pair 16. Then, the operation is stopped for a predetermined time in order to set the timing of image formation. At this time, the paper forms slack. It is arranged so that the most inflated portion of the slack is around the contact point between the mylars 41 and 42. By bringing the two mylars 41 and 44 into contact with each other in this manner, it is possible to suppress mutual vibration of the mylars 41 and 44. The deformation of the mufflers 41, 44 causes the bending of the paper while gradually dispersing the force, so that the paper is not flexibly bent and the vibration of the paper is suppressed, so that the noise is slightly generated. Second tray 11
When the paper is fed from the above, the above-mentioned operation is performed and the same operational effect is obtained. Moreover, since the sound leaking to the opening 30 is shielded by the exterior portion 31a, it is possible to reduce the noise.

Next, other embodiments will be described. In the description, parts having the same effects as the parts described above are designated by the same reference numerals, and detailed description of the parts will be omitted. To do.

In the second embodiment, a method of preventing a sound generated when the paper is re-fed and which is caused by a sharp extension of the bending of the front end of the paper will be described. FIG. 7 is a block diagram of a control system which is a carrier device of the present invention, and the control means 84 is a central processing unit (CPU) having various judgment and processing functions.
In response to signals from the registration detection 27, the relay detection 28, the paper size detection 33, etc., the main motor 35, the registration clutch 36, the paper feed clutch 37, and the relay clutch 38 are operated.
ROM, which is a program memory that stores programs for controlling ON / OFF and fixed data, RAM, which is a data memory that stores processing data, and input / output circuit (I / O)
And so on.

FIG. 8 is a diagram for explaining the transport path length from the paper feed trays 10 and 11 to the registration roller pair 16 and the transport speed of the paper. The following times are based on the assumption that there is no paper slip due to the rollers. 1st tray 1
Distance from 0 to registration roller pair 16 is L1 = 90m
m, the transport speed is 180 mm / s, the transport time is 0.
5 seconds. When the distance from the second tray 11 to the relay roller pair 24 is L2 = 90 mm and the transportation speed is 180 mm / s, the transportation time is 0.5 seconds. When the distance L3 from the relay roller pair 24 to the registration roller pair 16 is 110 mm and the transportation speed is 180 mm / s, the transportation time is 0.61 seconds. After the registration roller pair 16, the transport path length from the first tray 10 to the registration roller pair 16 is L1 = 90 m.
m, the transport path length from the second tray 11 to the registration roller pair 16 is L2 + L3 = 200 mm.

In short, the first tray 10 has a short distance to the registration roller pair 16, and even if the conveyance speed is lowered, it has little effect. Therefore, after the conveyance speed is lowered and the sheet is bent, the registration is performed when the sheet is re-conveyed. The roller pair 16 and the paper feed roller 14 were simultaneously operated to convey the paper while keeping the flexure of the paper. In addition, the paper feed roller 14 is set to 1 from the rear end of the paper.
The paper feed clutch 37 is disengaged so that the 0 mm portion remains.

FIG. 9 is an explanatory diagram of sheet tray size detection. The trays 10, 11, 12, and 13 have the same configuration, but the first tray 10 will be described here. A handle 34 for pulling out and a separation pad 25 are arranged on the tray 10. Further, on the front side of the first tray 10, a dial-switching type paper size detection 32,
33 is attached. With the first tray 10 pulled out, the dial 32 is rotated to select the set paper size. When the first tray 10 is set in the main body 1 in this state, the size detection switch 33 on the main body 1 side is pressed according to the paper size set in the dial. The size detection 33 detects the presence / absence of a tray set and the paper size.

FIG. 10 is a timing chart for explaining the second embodiment. The paper conveyance speed is 120 mm / s from the paper feed to the registration roller pair 16, and the registration roller pair 1
It is 120 mm / s after 6 as well. In the figure, the English letter a,
b, c, ... are the first motions, Roman numerals i, ii, ii
i, ... Are the operations of the second sheet. In addition, A is for flexure formation and B is for timing adjustment. In the embodiment of the present invention, all A4 horizontal size sheets are used.

In response to the start signal, the main motor 35 is rotated (a), and after a certain period of time, the paper feed clutch 37 is turned on.
When it becomes N (b), the paper feed roller 14 is rotated and the first paper feed from the first paper feed tray 10 is started. When the leading edge of the paper reaches the registration sensor 27 (c), the paper feed clutch 37 is turned off after a certain period of time, and the rotation of the paper feed roller 14 is stopped (d). Between c and d, the leading edge of the sheet hits the stopped registration roller pair 16 to form a bend. Between d and e, a timing adjustment time for image formation is taken, after which the registration clutch 36 and the paper feed clutch 37 are turned on (e, f), and the paper feed roller 14 and the registration roller pair 16 are rotated. , Convey paper with the paper bent. Then, with the trailing edge portion of the sheet of about 10 mm left on the paper feed roller 14, the paper feed clutch 37 is turned off to stop the paper feed roller 14 (g). Then, the feeding of the second sheet is started (i), the first sheet is pulled out of the registration roller pair 16 (h), and after a lapse of a certain time, the registration clutch 36 is turned on.
It becomes FF. Since the subsequent operations (ii to viii) for the second sheet are the same as those for the first sheet, the description thereof will be omitted.

As described above, in the first tray 10, the front end of the paper is temporarily stopped in a state of abutting against the registration roller pair 16, and the registration roller pair 16 is driven to transfer the paper in synchronism with the image forming portion. Although the sheet is fed to the position, since the registration roller pair 16 and the sheet feeding roller pair 14 are simultaneously driven at the same rotation speed, the sheet can be moved while keeping the deflection, and only the registration roller pair 16 is driven as in the conventional case. However, the collision noise of the paper due to the sudden buckling of the paper does not occur. Further, since the conveying speed is slowed down, the impact noise at the time of colliding with the registration roller pair 16 can be reduced.

Since the size of the paper can be detected by the size detectors 32 and 33 of the first tray 10, the paper feed clutch 3
By previously inputting the stop timing data of No. 7, a portion (10 m
m) can be set according to the paper size. Further, when waiting for the feeding of the second sheet until the trailing edge of the first sheet passes through the registration sensor, the feeding timing is delayed by 0.32 seconds for each sheet, and The number of image formations is reduced. Therefore, when feeding the second and subsequent sheets, it is set in advance so that the set sheet interval is obtained, and the sheets are fed at the set timing. For example, if the second sheet is set to be fed 0.25 seconds before the first sheet exits the registration sensor 27, the first sheet becomes 0.25 seconds later than the conventional one, but two sheets are fed. From the eyes onward, an image can be formed at the same timing as the conventional one.

Even when the feed roller 14 and the registration roller pair 16 are set at a constant speed, the registration roller pair 16 has a slip load of 1 to 2% because the axial load applied to the roller shaft is about 4 to 6 kgf. On the other hand, the paper feed roller 14 has a slip ratio of 10% at about 300 gf, the relay roller pair 24 has a slip ratio of about 2 to 8% at about 500 gf to 1 kgf,
Deflection is absorbed by the amount of slippage and noise generation is reduced. The axial load of the registration roller pair 16 is large, followed by the relay roller pair 24, and the smallest is the paper feed roller 14, which means that the drive of the downstream side is driven when the drive of the upstream side shaft is disconnected. This is because the paper is easily pulled by force.

FIG. 11 is a timing chart showing a state where one sheet is passed from the second tray 11. In response to the start signal, the main motor 35 rotates (a), after a certain time elapses, the paper feed clutch 37 is turned on (b), the paper feed roller 22 rotates, and the first paper feed from the second tray 11 is started. To do. After the operation of the paper feed clutch 37, the relay clutch 38 is turned on after a lapse of a certain time (c), and the relay roller pair 24
Rotate to transport the paper. When the paper reaches the relay sensor 28 (d), the paper feed clutch 37 is turned on after a certain period of time.
It becomes FF, and the rotation of the paper feed roller 22 is stopped (e).
In this state, the paper is still sandwiched between the paper feed roller 22 and the separation pad 26, so that the paper is pulled by the relay roller pair 24 until the rear end of the paper comes off. The leading edge of the sheet reaches the registration sensor 27 (f), and the relay clutch 38 is turned off after a certain period of time, and the rotation of the relay roller pair 24 is stopped (g). Between f and g, the leading edge of the paper hits the registration roller pair 16 that is stopped, and forms a bend. After the timing adjustment time (between g and h) for image formation, the registration clutch 36 and the relay clutch 38 are turned on again, the registration roller pair 16 and the relay roller pair 24 restart their driving, and the sheet remains in a bent state. It is transported as it is.

As described above, also in the second tray 11, after the sheet is bent, the registration roller pair 16 and the relay roller pair 24 are simultaneously driven when the sheet is re-conveyed, so that the sheet can be conveyed while keeping the deflection. You can prevent the noise when the paper is stretched rapidly. Also, unlike the first paper feed unit, the paper feed roller 2
Since the trailing edge of the sheet is gripped by the relay roller pair 24 instead of 2, the double feed unlike the sheet feeding roller 14 of the first tray 10 is not performed, so the drive of the relay roller pair 24 is cut off. No need.

In the second tray 11 of the above-described second embodiment, the paper cannot be conveyed at high speed, so that the image forming processing capability becomes lower than that of the conventional one. In the third embodiment, the conveyance speed to the registration roller pair 16 can be made high. In the second tray 11, the pair of registration rollers 16
And the relay roller pair 24 are directly connected to each other.
The second drive transmission means is not driven while the sheet is conveyed to the registration roller pair 16 and the second drive transmission means is used by the second drive transmission means during the re-conveyance from the registration roller pair 16. 16 and the relay roller pair 24 are driven simultaneously. The state in which the second drive transmission means is provided will be described below.

FIG. 12 is a schematic plan view of the paper transport drive system, FIG.
3 is a side sectional view of FIG. The main motor 35 is transmitting to the paper feed / conveyance drive system via the first timing belt 51. The first timing belt 51 rotates the first gear pulley 52 arranged on the stud 66. The first gear pulley 52 meshes with the registration gear 53 and the idle gear 54. The registration gear 53 is integrated with the registration clutch 36, and transmits the drive of the registration gear 53 to the registration roller 16 via the registration shaft 65. The idle gear 54 meshes with the second gear pulley 55,
The gear pulley 55 meshes with the first paper feed gear 56 and the relay gear 58.

The first paper feed gear 56 includes a paper feed shaft 68 and a bearing 76.
And a paper feed clutch (not shown). Relay gear 58
Is equipped with a relay clutch 38 and drives the relay roller 24 via a relay roller shaft 70. The second gear pulley is drivingly transmitted to the third gear pulley 61 via an idle pulley 60 and a second timing belt 57 having a belt tensioner 59. The third gear pulley 61 rotates around the stud 72 and serves as a drive source for the second sheet feeding unit. The third gear pulley 61 meshes with the second paper feed gear 62 and the second relay clutch 63.

In the present invention, the paper transport drive system 4 described above is used.
In addition to 9, a second drive transmission means is provided. That is, the registration roller 16 of the registration roller shaft 65 and the bearing 75
The first pulley 80 and the relay roller shaft 70 are provided with a second pulley 81 between them, and the timing belt 48 is stretched over both pulleys 80 and 81 so that the registration roller shaft 65 and the relay roller shaft 70 can directly drive and transmit. I did it. A one-way clutch 82 is provided on either one of the pulleys 80 and 81.

FIG. 14 shows the second pulley 8 of the relay roller shaft 70.
1 shows an example in which the one-way clutch 82 is provided, and FIG. 15 shows an example in which the first pulley 80 of the registration roller shaft 65 is provided with the one-way clutch 82. FIG. 14 shows a first pulley 80 that rotates integrally with the registration roller shaft 65 and a second pulley 80 that incorporates a one-way clutch 82 with a timing belt 48.
The case where the drive is given to the pulley 81 counterclockwise is shown. That is, the second pulley 81 makes the relay roller shaft 70
On the other hand, when it tries to rotate counterclockwise, the relay roller shaft 70 is driven by the wedge action of the cam surface of the one-way clutch 82 and the relay roller shaft 70 due to the effect of the roller 90 and the chevron shape 91. This is the case where the registration roller pair 16 rotates and the drive of the relay roller pair 24 is cut off.

The second pulley 81 tries to rotate clockwise relative to the relay roller 70 (actually, the relay roller shaft 70 tries to rotate counterclockwise with respect to the second pulley 81). ), The roller 90 and the chevron shape 91 cause the relay roller shaft 70 to idle.

Next, when the registration roller pair 16 conveys the first sheet to the photoconductor at 120 mm / s, the second sheet is conveyed by the relay roller pair 24 toward the registration roller pair 16 by 180 mm / s. The case of being transported by s will be described. In this case, the relay roller shaft 70 is 180 mm
The second pulley 81 rotates at a rotation speed corresponding to a conveyance speed of / s, and the second pulley 81 rotates at a rotation speed corresponding to a conveyance speed of 120 mm / s. The rotation speed of the second pulley 81 is 0 and the rotation speed of the relay roller shaft 70 is 60 mm / s. When the relay roller shaft 70 rotates at a relatively high speed,
Due to the action of the one-way clutch 82, the shaft idles, and the drive of the relay roller shaft 70 is not transmitted to the registration roller shaft 65.

In FIG. 15, the mounting direction of the one-way clutch 82 is set such that the mountain shape with respect to the rotation direction of the shaft is opposite to that in FIG. In this case, the registration roller shaft 6
When 5 tries to rotate counterclockwise with respect to the second pulley 81, the second pulley 81 rotates due to the wedge action of the cam surface of the one-way clutch 82 and the registration roller shaft 65 due to the effect of the roller 90 and the chevron shape. . Therefore, when the registration roller pair 16 starts refeeding, the relay roller pair 2
Even if the drive of 4 is cut off, the relay roller pair 24 rotates in synchronization with the rotation of the registration roller pair 16.

When the relay roller shaft 70 rotates counterclockwise and the drive is transmitted to the second pulley 81 by the first pulley 80 and the timing belt 48, that is, when the registration roller pair 16 is in the standby state, Due to the action of the one-way clutch 82, the second pulley 81 runs idle and does not transmit the drive to the registration roller shaft 65. Further, when both the registration roller shaft 65 and the second pulley 81 are driven in the same direction, and when the second pulley 81 has a relatively high rotation speed as in FIG. 14, the action of the one-way clutch 82 is generated. The pulley spins. Therefore, the drive of the relay roller shaft 70 is not transmitted to the registration roller shaft 65. However, the timing belt 48 operates.

That is, in the embodiment of FIG. 14, the timing belt 48 operates only when the registration roller pair 16 is driven, but in the embodiment of FIG. 15, either the registration roller pair 16 or the relay roller pair 24 is driven. At this time, the timing belt 48 operates. Therefore, noise is less generated in FIG. 14 because there is no unnecessary operation of the timing belt 48.

The flow of paper when the paper is fed from the second tray 11 will be described with reference to the timing chart of FIG.
The case where two horizontal sheets are continuously passed is described. In order to improve the image forming ability, when the first sheet passes through the relay sensor 28, the second sheet is fed. The sheet conveyance speed is from the sheet feed roller 22 to the registration roller pair 1.
Up to 6 was 180 mm / s, and after the registration roller pair 16 was 120 mm / s which is the image forming speed.

In response to the start signal, the main motor 35 is rotated (a), and after a certain period of time, the paper feed clutch 37 is turned on.
When it becomes N (b), the paper feed roller 22 rotates, and the feeding of the first sheet from the second tray 11 is started. After the operation of the paper feed clutch 37, the relay clutch 38 is turned on after a lapse of a certain time (c), and the relay roller 24 is rotated to convey the paper.
When the paper reaches the relay sensor 28 (d), the paper feed clutch 37 is turned off after a certain period of time, and the paper feed roller 22
Stops rotating (e).

The leading edge of the paper reaches the registration sensor 27 (f), and after a lapse of a certain time, the relay clutch 38 is turned off, and the rotation of the relay roller 24 is stopped (g). f-g
The leading edge of the sheet hits the pair of registration rollers 16 which is stopped during the interval to form a bend. After the timing adjustment time (between g and h) for image formation, the registration clutch 36
Is turned on (h), the registration roller pair 16 is driven, and the sheet is conveyed to the image forming unit. Conventionally, the relay roller 24 does not rotate when the relay clutch 38 is OFF, but in the present invention, since the one-way clutch 82 is connected, the drive is transmitted to the relay roller shaft 70 at the same timing as the registration roller shaft 65, and the relay roller shaft 70 is relayed. The roller 24 rotates. Therefore, since the sheet is conveyed in a state in which the deflection is maintained, the sound of the sheet suddenly expanding does not occur (hatched portion indicated by X).

When the paper feed clutch 37 is turned on again (i) and the paper feed roller 22 is rotated, the second tray 11 is rotated.
The second sheet is fed from. Then, the relay clutch 38 is turned ON after a certain time has passed (ii) the relay roller 2
4 is rotated and the paper is conveyed. When the second sheet reaches the relay sensor 28 (iii), the sheet feeding clutch 37 is turned off after a certain period of time, and the rotation of the sheet feeding roller 22 is stopped (iv). At this time, the first sheet passes the registration sensor 27 (j), and the registration clutch 36 is turned off (k) after a certain period of time. When the second sheet reaches the registration sensor 27 (v), the relay clutch 38 is turned off after a certain period of time (vi), and the relay roller 24
Stops rotating. From (vi) to (vii), both the relay clutch 38 and the registration clutch 36 are OFF, and the sheet is stopped for timing. After that, the registration clutch 36 is turned on (vii), the registration roller pair 16 is driven, and the sheet is conveyed to the image forming unit. From (vii) to (viii), the relay clutch 38 is OFF, but since the one-way clutch 82 is connected, the drive is transmitted to the relay roller shaft 70 at the same timing as the registration roller shaft 65, and the relay roller 24
Rotates. Therefore, it is possible to convey the sheet while keeping the deflection, and it is possible to prevent the generation of the sound of the sheet suddenly expanding (hatched portion indicated by Y).

The operation of the relay clutch 38, the registration clutch 36, and the one-way clutch 82 is shown below the timing chart of FIG. Between a and c, the relay clutch 38 and the registration clutch 36 are OFF, and between c and g, only the relay clutch 38 is ON, and the relay roller shaft 70 is rotated to convey the paper at high speed. At this time, the one-way clutch 82 idles, and the drive is not transmitted to the pulley. g ~
Between h, both relay clutch 38 and registration clutch 36 are O
This is FF, and the timing is being adjusted by stopping the paper. Between h and II, both the relay clutch 38 and the registration clutch 36 are OFF, but since the one-way clutch 82 is connected, the drive is transmitted to the relay roller shaft 70 at the same timing as the registration roller shaft 65, and the relay roller 2
4 rotates.

Therefore, since the sheet is conveyed in a state where the sheet is flexed, the sound of sudden extension of the sheet does not occur. ii
Between ~ k, the relay clutch 38 is turned on to pass the second sheet of paper. At this time, the registration clutch 36 is also ON because the first sheet is being conveyed. That is, the relay roller 24 conveys the second sheet at 180 mm / s, and the pair of registration rollers 16 conveys the first sheet at 120 m.
It is transported at m / s. At this time, the relay roller shaft 70
The relay roller pair 24 rotates at a rotation speed of 180 mm / s, and the pulley 120 mm / s by the timing belt 48.
It rotates at a rotation speed of s. When the rotation speed of the relay roller shaft 70 is higher than that of the pulley, the one-way clutch 82
Is idle, the registration roller pair 16 is 180 mm /
It does not rotate in s.

Between k and vi, the relay clutch 38 has two sheets of paper.
Since the first sheet is passed and hits the registration roller pair,
It is in the N state. On the other hand, the registration clutch 36 is in the OFF state because it has finished feeding the first sheet. At this time, the one-way clutch 82 idles, so that the drive is not transmitted to the pulley. Between vi and vii, both the relay clutch 38 and the registration clutch 36 are in the OFF state, and the sheet is stopped to adjust the timing.

The relay clutch 38 is turned off between vii and viii.
State, the registration clutch 36 is in the ON state. Although the relay clutch 38 is OFF, the drive is transmitted to the relay roller shaft 70 at the same timing as the registration roller shaft 65 because the one-way clutch 82 is connected, and the relay roller 24 is connected.
Rotates. Therefore, since the sheet is conveyed while keeping its deflection, the sound of sudden extension of the sheet does not occur.

As described above, by adding the drive system using the one-way clutch 82 between the registration roller shaft 65 and the relay roller shaft 70, the paper is transferred to the registration roller pair 16
Until it is conveyed to, the relay roller pair 24 can be rotated at a high speed by high rotation, and in this case, the rotation of the relay roller shaft 70 is not transmitted to the registration roller shaft 65. When the sheet is re-conveyed from the registration roller pair 16, the second sheet
The drive system can rotate the relay roller shaft 70 and the registration roller shaft at the same time.
It is possible to carry from 6 while keeping the deflection of the paper,
It is possible to prevent the sound generated when the paper is stretched suddenly.

FIG. 17 is a diagram showing experimental effects of the paper feeding device of the present invention. In the conventional example and the present example, the noise measurement is started at the same timing when the paper feed is started, and the measurement distance and the installation location of the measuring instrument are the same. The peak of the graph at the start of sheet feeding is the impact noise of the clutch when the sheet feeding clutch 37 is turned on. The collision sound when the paper collides with the pair of registration rollers 16 is about 1 in this embodiment as compared with the conventional example.
There is a 0 dB decrease, which is a significant difference. this is,
This is because the sheet is flexed slowly due to the impact absorbed by the mylar and the sound generated by the exterior portion 31a is shielded in this embodiment. The peak after the timing adjustment is an impact sound when the registration clutch 36 is turned on.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, although the present embodiment has been described assuming a monochrome copying machine, it may be related to a color copying machine, a printer, a FAX, or the like. The embodiment described by taking the second tray as an example can be applied to the case where the second tray is transported from another tray.

[0064]

According to the first aspect of the invention, the sheet conveyed from the sheet feeding means hits the registration roller adjusting means to form a bend, but the sheet member is deformed as the sheet bends. Since the deflection of the sheet is gradually dispersed, the vibration of the sheet can be suppressed without instantaneous bending, and the generation of sound can be reduced.

According to the second aspect of the present invention, the same effect as that of the first aspect is obtained, and by providing the sound insulating means at the attachment / detachment opening, the attachment / detachment opening is opened when the optional device is not used. It is possible to prevent the sound of the sheet hitting the registration roller adjusting means from the opening and the leakage of the sound generated when the sheet is bent.

According to the third aspect of the invention, when the sheet is re-conveyed,
Since only the registration roller adjusting means is not driven, and the rotation speed of the registration roller adjusting means is faster than the rotation speed of the downstream paper feed roller, only the registration roller adjusting means is driven as in the conventional case. By doing so, the sound that the deflection is suddenly expanded does not occur.

According to the invention described in claim 4, the same effect as the invention described in claim 3 is obtained, and the driving of the paper feeding means is stopped by leaving the trailing edge of the paper for a predetermined length. It is possible to prevent the sheets from being continuously fed.

According to the invention described in claim 5, the same effect as that of the invention described in claim 4 is obtained, and it is possible to prevent the continuous feeding of the paper regardless of the size of the paper.

In the sixth aspect of the present invention, since the relay conveying means and the registration roller adjusting means can rotate at the same number of revolutions at the same time, the sheet is conveyed from the registration roller conveying means while keeping the deflection. It is possible to prevent the sound generated when the paper is stretched suddenly.

According to the seventh aspect of the present invention, the same effect as that of the sixth aspect of the invention can be obtained, and the sheet can be conveyed at a high speed until the sheet hits the registration roller adjusting means, and the image forming speed is lowered. There is nothing to do.

According to the eighth aspect of the invention, the same effect as that of the seventh aspect of the invention can be obtained, and since the timing belt operates only when the registration roller adjusting means is driven, there is no unnecessary timing belt operation. Low noise generation.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a sheet conveying device according to an embodiment.

FIG. 2 is a diagram showing a change in shape of a mylar when paper is fed from a first tray.

FIG. 3 is a diagram in which a sheet is actually conveyed from the first tray.

FIG. 4 is a view showing a shape change of a mylar when a paper is fed from a second tray.

FIG. 5 is a diagram in which a sheet is actually conveyed from a second tray.

FIG. 6 is a schematic cross-sectional view of a digital copying machine that is an example of an image forming apparatus.

FIG. 7 is a block diagram of a control system that is a carrying device of the present invention.

FIG. 8 is a diagram in which a sheet is actually conveyed from the first tray.

FIG. 9 is an explanatory diagram of sheet tray size detection.

FIG. 10 is a timing chart illustrating a second embodiment.

FIG. 11 is a timing chart showing a state in which one sheet is passed from the second tray in the second embodiment.

FIG. 12 is a schematic plan view of a paper transport drive system.

FIG. 13 is a side sectional view of FIG.

FIG. 14 is a diagram in which a one-way clutch is provided on the second pulley of the relay roller shaft.

FIG. 15 is a diagram in which a one-way clutch is provided on the first pulley of the registration roller shaft.

FIG. 16 is a timing chart showing the flow of paper when the paper is fed from the second tray in the third embodiment.

FIG. 17 is a diagram showing experimental effects of the paper feeding device of the present invention.

FIG. 18 is a diagram showing a conventional paper transport device.

FIG. 19 is a timing chart showing a case where a sheet is conveyed from the first tray of the conventional example.

FIG. 20 is a timing chart showing a case where a sheet is conveyed from the second tray of the conventional example.

[Explanation of symbols]

14, 22 Paper feeding rollers (paper feeding means) 16 Registration roller pair (registration roller adjusting means) 24 Relay roller pair (relay transportation means) 40, 43 Guide member (buffer means) 41, 42, 44, 45 Mylar (sheet 82) One-way clutch (one-way driving means)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3F049 DA12 EA13 LA01 LA05 LA07                 3F101 FA03 FB02 FD04 FE02 LA02                       LA05 LA07 LB03                 3F102 AA02 AA10 AA11 AB01 BA02                       BB02 DA08 EA03 FA06 FA08                 3F343 FA02 FB02 FB03 FB04 FC28                       HA06 KB02 KB08

Claims (8)

[Claims] 1. A paper feed means for accommodating and transporting a paper sheet, and a registration roller adjusting means for carrying the paper sheet transported from the paper feeding means. In a sheet conveying device that starts to convey a sheet again at a predetermined timing after holding the sheet, a buffering unit is provided in a bend forming portion of the sheet, and the buffering unit includes a plurality of elastic sheet members, and one sheet member The sheet conveying device, wherein the front end of the sheet is in contact with the antinode of the other sheet member at a predetermined angle. 2. A registration roller adjusting means for conveying the paper conveyed from a detachable paper feed tray, the paper is abutted against the registration roller adjusting means to have a bend, and then again at a predetermined timing. 2. The sheet conveying apparatus according to claim 1, wherein a sound insulating unit is provided at a mounting / demounting port for detaching the optional apparatus when the optional apparatus is not used in the sheet conveying apparatus for starting sheet conveyance. 3. A paper feed unit for accommodating and transporting the paper, and a registration roller adjusting unit for carrying the paper transported from the paper feeding unit. The paper is abutted against the registration roller adjusting unit. In a sheet conveying device that starts conveying a sheet again at a predetermined timing after giving a bend, the registration roller adjusting means is operated at a predetermined timing to start the sheet conveyance again. The paper transporting device is faster than the paper transporting speed of the upstream paper transporting means. 4. When the sheet is abutted against the registration roller adjusting means and temporarily stopped, and when the sheet is re-conveyed from the registration roller adjusting means, the registration roller adjusting means and the paper feeding means are driven in synchronization, and thereafter. 4. The sheet conveying device according to claim 3, wherein the driving of the sheet feeding unit is stopped in a state where the sheet trailing end is sandwiched by the sheet feeding unit. 5. The sheet conveying apparatus according to claim 4, wherein a stop time for nipping the trailing edge of the paper is calculated according to the paper size, and the driving of the paper feeding unit is stopped based on the stop time. 6. A paper feed means for accommodating and transporting paper, a registration roller adjusting means for carrying the paper transported from the paper feeding means, and one between the paper feeding means and the registration roller adjusting means. In the paper conveyance device including the above-mentioned relay conveyance means, which allows the registration roller adjusting means to have a bend by hitting the paper and then starts conveying the paper again at a predetermined timing, the registration roller adjusting means and the relay conveyance means are provided. Is provided with a second drive transmission means for directly connecting them, and when the sheet is re-conveyed from the registration roller adjusting means, the registration roller adjusting means and the relay conveying means are driven in synchronization with each other. apparatus. 7. The second drive transmission means is provided with the one-way drive transmission means on either the registration roller adjusting means or the relay conveying means, and the second drive transmitting means is provided until the sheet is conveyed to the registration roller adjusting means. 7. The paper transporting device according to claim 6, wherein the drive transporting means rotates so that the paper transporting speed of the relay transporting means rotates faster than the paper transporting speed of the registration roller adjusting means. 8. The second drive transmission means transmits the driving force by a timing belt, and the one-way drive transmission means comprises:
The sheet conveying apparatus according to claim 7, wherein the sheet conveying apparatus is provided in the relay conveying means.