JP2011043732A - Document feeder and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document feeder capable of surely improving a stacking property of an ejected document while alleviating a user's burden, and an image forming apparatus to which the document feeder is mounted. <P>SOLUTION: The document feeder includes: reading side rollers (36 and 37) capable of conveying the document conveyed from an upstream side toward an ejection roller (42) from a reading part (7); a reading side drive means driving the reading side rollers by varying reading speed set in each reading mode; an ejection side drive means installed separately from the reading side drive means and driving the ejection roller at predetermined ejection speed; and a control means (80) changing the ejection side drive means within a range that the set reading speed is varied after the trailing edge of the document passes through the reading side roller. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a document feeding device that transports a document to a predetermined image reading position and an image forming apparatus equipped with the document feeding device.

This type of image forming apparatus is equipped with a document feeder and a reading unit, and a document set on a document tray of the document feeder is conveyed toward an image reading position of the reading unit, and an image surface thereof is read. .
In an image forming apparatus using an electrophotographic process, a photosensitive drum is charged in advance and an electrostatic latent image is formed by irradiating the surface of the drum with laser light. Next, the developed toner image is transferred and fixed on a sheet.

  Here, the document feeder has a reading-side roller facing the reading unit, and the rotation speed (reading speed) of the reading-side roller is set corresponding to the reading mode set on the operation panel or the like. The The reading speed also varies depending on the performance of the image forming apparatus on which the document feeder is mounted.

  On the other hand, the document conveyed from the document tray is sent to the discharge tray of the document feeder at a predetermined discharge speed. If this discharge speed is set equal to the reading speed described above, the document does not reach the discharge tray. There is a bug. Therefore, a technique for changing the discharge speed with respect to the reading speed is disclosed (for example, see Patent Document 1).

JP-A-2-210339

By the way, the discharge tray described above is positioned below the discharge roller in the vicinity of the discharge roller, and has a shape that is inclined upward along the discharge direction, so that single-sheet discharge originals can be stacked in the thickness direction. is there.
That is, in view of the shape of the discharge tray and the fact that the reading speed varies depending on the reading mode and the like, when the document is sent to the discharge tray, an optimal discharge satisfying the consistency (stackability) of the discharged document is provided. There should be speed.

However, in the above-described conventional technology, the discharge speed is simply made higher than the reading speed, and no particular consideration is given to fine control for improving the stackability.
In this case, it may be possible to separately provide a guide for aligning the leading edge of the discharged document on the discharge tray. However, considering the various sizes of the discharged document, it is necessary to change the position of the guide as appropriate. Inconvenient.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a document feeding device and an image forming apparatus equipped with the document feeding device, which can solve the above-mentioned problems and reduce the burden on the user while reliably improving the stackability of discharged documents.

A first invention for achieving the above object is a document feeding device for feeding a document conveyed from a document tray and having its image surface read by a reading unit to a discharge tray by a discharge roller.
A reading-side roller capable of conveying the document conveyed from upstream toward the discharge roller from the reading unit; and a reading-side driving unit configured to drive the reading-side roller while changing the reading speed to a reading speed set for each reading mode. The discharge-side drive means is installed separately from the reading-side drive means, and the discharge-side drive means for driving the discharge roller at a predetermined discharge speed, and the discharge-side drive means after the trailing edge of the document has passed the read-side roller, And control means for changing within a variable range of the set reading speed.

According to the first invention, the document is sent to the discharge tray by the discharge roller after the image surface is read by the reading unit.
Specifically, the reading-side roller can convey the document read by the reading unit toward the discharge roller, and the reading-side roller is read at a reading speed set for each reading mode by the reading-side driving unit. To drive. For example, based on the reading speed in the standard mode, the reading speed in the high-speed scanning mode is faster than the reading speed in the standard mode, and the reading speed in the mode that requires high image quality is slower than the reading speed in the standard mode.

  Here, if the discharge roller is also driven at the same reading speed, if the reading speed is low, the discharge speed of the discharge roller also becomes low, so that the trailing edge of the document tends to remain on the discharge roller. On the other hand, when the reading speed is high, the discharge speed is also increased, so that the document is easily dropped from the discharge tray, and in any case, the stackability of the discharged document is deteriorated.

However, discharge speed acceleration / deceleration control is applied to the control means of the present invention.
Specifically, the discharge side driving means is installed separately from the reading side driving means, and the discharge roller is driven separately from the reading side roller. While the document is being conveyed by the reading side roller, the discharge roller rotates at the same speed as the reading side roller. However, after the trailing edge of the document has passed the reading side roller, Rotate at a speed of.
As described above, if the discharge speed is changed within the variable range of the reading speed, the optimum discharge speed can be aimed at, and the stackability of the discharged original can be improved.

According to a second aspect of the present invention, in the configuration of the first aspect, after the trailing edge of the document has passed the reading side roller, the control means sets the reading speed set to the discharge side driving means from a predetermined reference speed. If the reading speed is higher than the slow reading speed, the discharging speed is made slower than the fast reading speed when the set reading speed is faster than a predetermined reference speed. .
According to the second invention, in addition to the operation of the first invention, the reading speed is within a variable range of the reading speed, and the reading speed is less than the predetermined speed on the basis of the predetermined speed (for example, the reading speed in the standard mode). In this case, the discharge speed is faster than the reading speed, whereas when the reading speed is equal to or higher than a predetermined speed, the discharge speed is slower than the reading speed.
Therefore, not only can the discharge speed be freely changed with respect to the reading speed, but the fine paper control does not reach the high document reading speed on the discharge tray, but the slow reading speed is exceeded. Therefore, it is possible to aim at a high discharge speed, and it is possible to reliably improve stackability of discharged originals while reducing the burden on the user as compared with the conventional case.

According to a third invention, in the configuration of the first or second invention, the control means sets the discharge speed after the trailing edge of the document has passed the reading-side roller to be substantially constant within the range of the reading speed. Features.
According to the third invention, in addition to the effects of the first and second inventions, the discharge speed is always kept constant regardless of the value of the reading speed. This also contributes to improving the stackability of the discharged document.

According to a fourth aspect of the present invention, in the configuration of the first to third aspects of the present invention, the apparatus further comprises detection means for detecting the state of the document sent to the discharge tray, and the control means is configured to discharge the sheet according to the detection result of the detection means Is further changed.
According to the fourth aspect of the invention, in addition to the effects of the first to third aspects, the discharge tray is formed so that sheets of discharged originals can be stacked in the thickness direction. The discharge speed is increased or decreased as compared with the reading speed, and can be further increased or decreased in view of the state of the discharged document, so that the stackability of the discharged document can be further improved.

According to a fifth aspect of the invention, in the configuration of the fourth aspect of the invention, the detecting means is a counter for measuring the number of documents sent to the discharge tray, and the control means is configured to discharge the sheet when the number of documents by the counter is small. For the side drive means, the discharge speed is made faster than the value obtained from the relationship with the reading speed.
According to the fifth aspect of the invention, in addition to the action of the fourth aspect of the invention, when the number of discharged originals is small, the leading edge of the original discharged from the discharge roller is resisted by the inclination of the discharge tray in the vicinity of the discharge roller. As a result, the trailing edge of the document is likely to remain on the discharge roller. However, since the control means in this case increases the document discharge speed, this point also contributes to improving the stackability of the discharged document.

According to a sixth invention, in the configuration of the fourth or fifth invention, the detection means is a counter for measuring the number of documents sent to the discharge tray, and the control means is used when the number of documents by the counter is large. Is characterized in that the discharge speed is made slower than the value obtained from the relationship with the reading speed for the discharge side driving means.
According to the sixth invention, in addition to the effects of the fourth and fifth inventions, when the number of discharged originals is already large, the leading edge of the original is along the uppermost layer of the originals already placed. As a result, the document is more easily dropped from the discharge tray. However, since the control means in this case slows down the document discharge speed, the end surfaces of the discharged document are more easily aligned, which also contributes to improving the stackability of the discharged document.

According to a seventh invention, in the configuration of the fourth or fifth invention, the detecting means is a counter for measuring the number of documents sent to the discharge tray, and the control means is for increasing the number of documents by the counter. In proportion to the discharge-side drive means, the discharge speed is gradually made slower than the value obtained from the relationship with the reading speed.
According to the seventh invention, in addition to the effects of the fourth and fifth inventions, the control means gradually slows down the document discharge speed in accordance with the number of discharged documents. Are even more certain.

The eighth invention is an image forming apparatus equipped with any one of the first to seventh document feeders.
According to the eighth invention, in addition to the effects of the first to seventh inventions, the stackability of the discharged document is further improved, so that the user's work period for the image forming apparatus can be shortened. Reliability is also improved.

  According to the present invention, it is possible to provide a document feeding device in which the discharge speed is finely controlled, reducing the burden on the user, and improving the stackability of the discharged document, and an image forming apparatus equipped with the same.

1 is a cross-sectional front view of a multi-function peripheral equipped with a document feeder of this embodiment. FIG. 2 is a perspective view of the document feeder in FIG. 1. FIG. 3 is a cross-sectional front view of the document feeder of FIG. 2. FIG. 3 is a control block diagram of the document feeder in FIG. 2. It is a flowchart of discharge speed acceleration / deceleration control by the controller of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross section viewed from the front side of a multifunction machine 1 which is an example of an image forming apparatus.
The multifunction machine 1 of this embodiment has an in-body discharge-type apparatus main body 2, and a discharge tray 14 is formed below the reading unit 7.

  An original feeding device 20 is mounted on the upper side of the apparatus main body 2, more specifically, on the upper side of the reading unit 7, and the original feeding device 20 is configured to be able to automatically convey the original to a predetermined image reading position (ADF: Auto Document Feeder). Specifically, when the multifunction device 1 is used as a copying machine, a facsimile, or a network scanner, a document is transported from the document feeder 20 and its image surface is optically read by the reading unit 7.

  On the other hand, a front loading type paper supply device is disposed at the lower part of the apparatus main body 2. Specifically, the supply device according to the present exemplary embodiment is provided with two upper and lower paper feed cassettes 3 along the height direction of the main body 2. Each cassette 3 is configured to be detachable from the main body 2, and when pulled out toward the front side of the multifunction device 1, the inside of the cassette 3 is opened to the outside, while the rear surface of the multifunction device 1. When pushed toward the side, the inside is closed.

In addition, arrows indicated by solid lines in the same figure represent a sheet conveyance path and its conveyance direction.
Various cassettes P before image formation are accommodated in each cassette 3 in a stacked state, and the sheets P are separated one by one from the cassette 3 and sent out in the left direction in the figure. The paper P in the transport path 4 is transported upward along the left side surface of the apparatus main body 2.

In addition, an openable manual feed tray 5 is provided on the right side surface of the apparatus main body 2, and the sheet fed from the manual feed tray 5 is also transported to the transport path 6 and then transported upward.
Inside the apparatus main body 2, a registration roller, an image forming unit 9, and a transfer unit 10 are sequentially arranged on the downstream side when viewed in the sheet conveyance direction. An exposure unit 8 and a toner container 11 are provided on the right side of the image forming unit 9, and laser light L is irradiated from the exposure unit 8 toward the photosensitive drum of the image forming unit 9. The toner is developed.

A fixing unit 12 and a discharge branching unit 13 are sequentially arranged on the downstream side of the transfer unit 10 when viewed in the paper conveyance direction, and a duplex printing unit 16 is arranged on the left side of the conveyance path 4. The duplex printing unit 16 includes a reverse conveyance path having one end connected to the downstream side of the fixing unit 12 in the conveyance path 4 and the other end connected to the upstream side of the image forming unit 9. In the case of single-sided printing, the paper discharged from the fixing unit 12 is discharged to the paper discharge tray 14 via the discharge roller 15.
On the other hand, in the case of double-sided printing, the paper is once sent to the paper discharge tray 14 and then switched back to the reverse conveyance path of the duplex printing unit 16 by the reverse drive of the discharge roller 15. 4 is returned to the upstream side of the image forming unit 9 and sent again toward the image forming unit 9.

Here, the document feeder 20 described above has a feeder main body 21 that can transport a document placed on the right side of FIG. 1 to the left and discharge it again to the right.
Specifically, as shown in FIG. 2, the feeder main body 21 has a document tray 22 that extends obliquely upward to the right from the central portion, and the document tray 22 is located at the central portion. Thus, the document is read from the reading position 39 and set on the document tray 22.

The document tray 22 is provided with a width alignment guide 28, and the width alignment guide 28 is configured to be movable in the document width direction. When the width alignment guide 28 comes into contact with the side end portion of the document set on the document tray 22, the document setting position is determined.
The feeder main body 21 includes a paper feed cover 25 on the left side of the document tray 22 (FIGS. 2 and 3).

  The paper feed cover 25 is rotatably supported by the feeder main body 21 at the left end in the figure, and can open and close a document transport path disposed inside the paper feed cover 25 with respect to the outside. That is, the paper feed cover 25 in the state shown in the figure has the conveyance path closed, and the outer surface of the paper feed cover 25 corresponds to the top surface of the document feeder 20, while the inner surface of the paper feed cover 25 is conveyed. It functions as a road guide.

Here, when the paper feed cover 25 is rotated counterclockwise as viewed in FIGS. 2 and 3, the above-described transport path is opened, and various rollers disposed around the transport path can be seen. it can.
More specifically, a pickup roller 30, a separation roller pair 33, and a registration roller 35 are sequentially arranged in this conveyance path when viewed in the document conveyance direction from the document tray 22 (FIG. 3).

The pickup roller 30 is installed on the paper feed cover 25, contacts a document located on the uppermost layer of the document tray 22, and sends the document toward the separation roller pair 33. Whether or not the document is conveyed and the orientation of the document can be detected by a set switch or the like installed on the paper feed cover 25.
The separation roller pair 33 is provided on each of the paper feed cover 25 and the feeding apparatus main body 21, and feeds the document one by one toward the registration roller 35.

The registration roller 35 forms a nip with the opposing roller and feeds the document to the reading position 39 at the adjusted predetermined timing while correcting the oblique feeding of the document.
Further, a reading guide 38 is disposed on the downstream side of the registration roller 35 when viewed in the document conveying direction, and faces the contact glass of the reading unit 7. Specifically, this contact glass is composed of a wide document placing glass and a long and narrow document automatic reading glass located on the left side of the document placing glass in FIG.

More specifically, the document feeder 20 of the present embodiment also functions as a document presser, and the feeder main body 21 is rotatably supported by the apparatus main body 2 on the back side of the multifunction machine 1. The apparatus main body 21 can be opened and closed with respect to the reading unit 7.
Then, a resin-made pressing plate is provided on the lower surface of the feeding device main body 21, and the former document placement glass faces the pressing plate. When the original placed on the glass is pressed with a pressing plate and a predetermined button is pressed down, the image surface of the original can be read by a CCD via a mirror, a lens or the like disposed in the reading unit 7.

On the other hand, the latter glass for automatic reading of the document faces the reading guide 38 at the reading position 39 in FIG.
Specifically, a reading-side roller 36 is installed in the feeding apparatus main body 21 on the upstream side of the reading guide 38 when viewed in the document conveying direction, and a nip is formed with the opposing rollers so that the document faces the reading guide 38. Transport. When the document passes between the reading guide 38 and the automatic document reading glass, the image surface of the document is read.

  A reading side roller 37 and a path switching unit 40 are installed on the downstream side of the reading guide 38. The path switching unit 40 can switch between a conveyance path from the reading position 39 toward the reversing tray 23 and a conveyance path from the reading position 39 toward the discharge tray 24. And the document is conveyed toward the reverse tray 23 and the discharge tray 24 in accordance with the position of the path switching unit 40.

Here, when the conveyance path directly from the reading position 39 to the discharge tray 24 is selected by the path switching unit 40, the discharge roller 42 is disposed on the downstream side of the reading roller 37 when viewed in the document conveyance direction. The discharge tray 24 is arranged in this order.
The discharge roller 42 forms a nip with the opposing roller, and sends the document read at the reading position 39 to the discharge tray 24.

As shown in FIG. 3, the discharge tray 24 is positioned below the discharge roller 42 in the vicinity of the discharge roller 42, and has a shape inclined upward along the discharge direction. Can be laminated in the thickness direction.
On the other hand, when the conveyance path from the reading position 39 toward the reversing tray 23 is selected by the path switching unit 40, the reversing roller 44, The reversing trays 23 are arranged in this order.

The reversing tray 23 of this embodiment is used when both the front surface and the back surface of the document are read at the reading position 39.
Specifically, the reverse tray 23 is disposed between the document tray 22 and the discharge tray 24, and extends in the discharge direction like the document tray 22, and places a document between the document tray 22. It has a space where it can be placed.

The reversing roller 44 is provided in the vicinity of the discharge roller 42 and has a function of conveying the document from the reading side roller 37 toward the reversing tray 23, and the direction in which the document on the reversing tray 23 is conveyed. It has a function of conveying in the reverse direction.
When the reversing roller 44 rotates clockwise as viewed in FIG. 3, the document read at the reading position 39 can be conveyed to the reversing tray 23. On the other hand, when the reversing roller 44 rotates counterclockwise, the traveling direction of the document conveyed to the reversing tray 23 is reversed, and the document on the reversing tray 23 is directed toward the registration roller 35 or switched back. It can be conveyed toward the path 47.

As described above, there are two paths in the direction of switching back the document, and these paths are selected by the path switching unit 41 located on the left side of the reverse roller 44 as viewed in FIG.
Then, if it is necessary to read the front surface and the document conveyed to the reversing tray 23 and then the back surface, the path switching unit 41 selects a conveying path from the reversing tray 23 to the registration rollers 35. The reverse roller 44 cooperates with the roller 45 to convey the original on the reverse tray 23 toward the registration roller 35.

  On the other hand, when the back side is also read at the reading position 39 thereafter, the document is conveyed to the reverse tray 23. In this case, the path switching unit 41 does not select the transport path from the reversing tray 23 toward the registration roller 35, selects the transport path from the reversing tray 23 toward the switchback transport path 47, and the reversing roller 44 has a roller 45. The document on the reverse tray 23 is conveyed toward the switchback conveyance path 47 in cooperation with the above.

  The switchback conveyance path 47 of this embodiment communicates the conveyance path from the reading position 39 to the reversing tray 23 and the conveyance path from the reading position 39 to the discharge tray 24. It is formed in a substantially C shape having a small curvature as compared with a greatly curved path that reaches the discharge tray 24 directly via the roller 35 and the reading position 39.

The switchback conveyance path 47 is provided with a conveyance roller 48 in the vicinity of the reversing roller 44, and a nip is formed with the opposite roller, and the original conveyed on the conveyance path 47 is conveyed toward the discharge roller 42. To do.
Here, the various rollers 30, 33, 35 to 37, 42, 44, 48 described above are controlled by a controller (control means) 80 in the feeder main body 21 (FIG. 4).

  As shown in the figure, the controller 80 of this embodiment includes a path control unit 82 and a motor control unit 84. For example, the controller 80 selects a reading mode set by input from an operation panel (not shown). Based on this, a predetermined program is executed. More specifically, the path control unit 82 outputs a drive signal to the above-described path switching units 40 and 41 to determine a document transport path.

The motor controller 84 outputs drive signals to the motors that drive the various rollers 30, 33, 35 to 37, 42, 44, and 48.
Specifically, the motor control unit 84 of this embodiment includes a reading side adjustment unit 86 and a discharge side adjustment unit 88, and drives the reading side rollers 36 and 37 and the discharge roller 42 by separate motors.

  More specifically, the reading side adjustment unit 86 outputs a driving signal to the reading side motor based on a signal from the mode setting unit 72 of the main ECU 70. For example, the reading side adjustment unit 86 outputs a standard signal, a high-speed scan mode, or a high image quality ( When one of the modes requiring high resolution is selected as described above, the reading speed is set. As a result, when the reading side adjustment unit 86 outputs a signal for driving at the reading speed corresponding to each mode to the reading side motor (reading side driving means), the reading side rollers 36 and 37 rotate at the reading speed.

If the reading speed in the standard mode is used as a reference, the reading speed in the high-speed scan mode is faster than the reading speed in the standard mode, and the reading speed in the mode that requires high image quality is slower than the reading speed in the standard mode.
On the other hand, after the trailing end of the document has passed the reading side roller 37, the discharge side adjusting unit 88 determines the reading speed set by the reading side adjusting unit 86, that is, the rotation speed of the reading side rollers 36 and 37. Outputs a signal for driving at different discharge speeds to the discharge motor (discharge drive means).

More specifically, when the set reading speed is slow, for example, in a mode that requires high image quality, the discharge side adjustment unit 88 sends a signal that makes the discharge speed faster than the slow reading speed in the mode. Output to the motor. Thereby, the discharge roller 42 rotates at a higher discharge speed than the slow reading speed in the mode.
On the other hand, when the set reading speed is high as in the high-speed scan mode, for example, a signal for making the discharge speed slower than the high reading speed is output to the discharge side motor, and the discharge roller 42 depends on the mode. Rotates at a slower discharge speed than the fast reading speed.

As described above, the discharge-side adjustment unit 88 reduces or increases the discharge speed of the discharge roller 42 according to the set reading speed. However, the controller 80 detects, for example, a document placed near the discharge roller 42. A signal from a counter (detection means) 90 capable of detecting the number of sheets is also input.
In this embodiment, the discharge roller 42 is configured to be driven separately from the reading side rollers 36 and 37, so that the discharging side adjustment unit 88 determines the detection result of the counter 90 in addition to the relationship with the reading speed. Based on this, the discharge speed can be further reduced or increased.

Referring to FIG. 5, a flowchart of discharge speed acceleration / deceleration control by the controller 80 is shown. Hereinafter, the operation according to the present invention of the document feeder 20 configured as described above will be described.
In step S501 in the figure, for example, a reading mode of a standard mode, a high-speed scan mode, or a mode requiring high image quality is set on the operation panel or the like, and the process proceeds to step S502.

In step S502, reading of the document is started at the reading position 39. Specifically, the uppermost document among the documents set on the document tray 22 is conveyed toward the reading position 39 via the registration roller 35 and the reading side roller 36 by pressing a predetermined button, and the reading position 39 Is read.
Subsequently, when only one side of the document is read based on a signal from the path control unit 82, it is conveyed directly from the reading side roller 37 toward the discharge roller 42.

  Alternatively, when both sides of the original are read, the reading side roller 37 passes through the reversing tray 23, the registration roller 35, the reading side roller 36, the reading position 39, the reversing tray 23, and the switchback conveyance path 47 and then discharged. It is conveyed toward the roller 42. These reading side rollers 36 and 37 rotate at respective reading speeds set by the reading side adjusting unit 86.

  On the other hand, the discharge side adjustment unit 88 sets a discharge speed that is increased / decreased from the reading speed set by the reading side adjustment unit 86, and the discharge roller 42 rotates at this discharge speed. For example, in the case of a reading speed in a mode that requires high image quality, the discharge speed is made faster than the reading speed, and in the case of a reading speed in a high-speed scan mode, the discharging speed is made higher than the reading speed. Slow down. In the case of the reading speed in the standard mode, the discharging speed may be set substantially the same as the reading speed, and the discharging speed in this case is changed according to the next counted number of sheets.

Next, in step S503, the controller 80 determines the state of the discharged document sent to the discharge tray 24 by the discharge roller 42. For example, is the number of documents measured by the counter 90 smaller than the predetermined number A? Determine whether or not.
If the number of originals by the counter 90 is smaller than the predetermined number A, that is, in this case, it is necessary to adjust so that the originals are discharged along the inclined portion of the discharge tray 24. In step S504, the discharge side adjusting unit 88 sets a discharge speed faster than the discharge speed value obtained from the relationship with the reading speed described above, and rotates the discharge roller 42 via the discharge side motor. Let

This point will be described in detail. Assuming that the maximum stack number of the discharge tray 24 is, for example, 100 sheets, and assuming that the discharge speed when the stack number of the discharge tray 24 reaches 50 sheets is E, the discharge side adjustment unit 88 is When the number of stacked discharge trays 24 is 0 to 25, a discharge speed faster than the discharge speed E is set.
As a result, when a slow discharge speed is set when the number of discharge trays 24 is small, the leading edge of the document sent from the discharge roller 42 hangs down and enters the inclined portion of the discharge tray 24 at a steep angle, and the document is stuck. The paper is bent or rounded, or the load when climbing the inclined portion of the discharge tray 24 is increased, so that the document sent from the discharge roller 42 is bent immediately after being discharged, resulting in poor discharge. However, due to the setting of the discharge speed by the discharge side adjustment unit 88, the leading edge of the document sent from the discharge roller 42 enters at a gentle angle with respect to the inclined portion of the discharge tray 24, and when the rising portion rises. The load is also reduced, and poor discharge can be avoided.

Subsequently, in step S505, the controller 80 determines whether or not reading of the document set on the document tray 22 has been completed. If reading of all the documents has not been completed, the process returns to step S502. On the other hand, when all the originals have been read, the series of routines are exited.
On the other hand, when the number of documents measured by the counter 90 reaches the predetermined number A in step S503, the process proceeds to step S506.

  In step S506, the discharge side adjustment unit 88 sets a discharge speed slower than the discharge speed value obtained from the relationship with the reading speed described above, and rotates the discharge roller 42 via the discharge side motor. This is because it is necessary to adjust so that the leading edge of the document does not jump out of the discharge tray 24. Then, the process proceeds to step S505, and a series of routines are exited after all the originals have been read.

More specifically, the discharge side adjustment unit 88 sets the same value as the discharge speed E when the number of stacked discharge trays 24 is 26 to 74, while the number of stacked discharge trays 24 is 75 to 100. For the sheet, a discharge speed slower than the discharge speed E is set.
As a result, when the number of discharge trays 24 is large, there is not enough room in the height of the document stopper (not shown) that can be installed at the end of the discharge tray 24. The original document jumps out of the discharge tray 24 beyond the document stopper, resulting in a discharge failure. However, according to the setting of the discharge speed by the discharge side adjustment unit 88, the document sent from the discharge roller 42 does not jump out from the discharge tray 24 toward the outside of the apparatus main body 2, and discharge failure can be avoided.

  On the other hand, in the multi-function device 1 equipped with the document feeding device 20, the sheets are separated and sent one by one from the cassette 3 and the manual feed tray 5, and the sheets reach the registration rollers in the apparatus main body 2. This registration roller feeds the paper to the transfer unit 10 while correcting the oblique feeding of the paper and timing the toner image formed by the image forming unit 9.

Further, based on the image data of the reading unit 7, irradiation of the laser beam L by the exposure unit 8 is controlled in the multifunction device 1. As a result, an electrostatic latent image of the document image is created on the drum in the image forming unit 9, and then a toner image is formed on the drum from the latent image using the toner in the toner container 11 and transferred to a sheet. .
Thereafter, the sheet is fed toward the fixing unit 12 with an unfixed toner image carried thereon, and the toner image is fixed. Next, the paper discharged from the fixing unit 12 is discharged to the paper discharge tray 14 through the discharge branching unit 13.

When double-sided printing is performed in contrast to this single-sided printing, the paper discharged from the fixing unit 12 is sent to the paper discharge tray 14 and then switched to the double-sided printing unit 16 side by reverse driving of the discharge roller 15. The sheet is fed back to the conveyance path 4 and sent again toward the transfer unit 10. In this case, the toner image is transferred to the surface of the paper that has not been printed.
In this embodiment, the discharge speed of the discharge roller 42 is changed based on the predetermined number A. However, the discharge speed may be gradually decreased in proportion to the increase in the number of documents by the counter 90.

  On the other hand, in the above embodiment, the discharge speed of the discharge roller 42 is set within a range from a slow reading speed to a high reading speed. However, the discharge side adjustment unit 88 may adjust the discharge speed of the discharge roller 42 to be substantially constant between the slow reading speed and the high reading speed. This is because the discharge speed of the original on the discharge tray 24 can be kept more constant by this fixed discharge speed, which also contributes to improving the stackability of the discharged original.

As described above, according to this embodiment, the document is sent to the discharge tray 24 by the discharge roller 42 after the image surface is read at the reading position 39.
Specifically, the reading side rollers 36 and 37 can convey the document read at the reading position 39 toward the discharge roller 42, and the reading side rollers 36 and 37 are read by the reading side motor for each reading mode. Drives at the reading speed set to.

  Here, if the discharge roller 42 is also driven at the same reading speed, if the reading speed is slow, the discharge speed of the discharge roller 42 is also slow, so that the trailing edge of the document remains on the discharge roller 42. It becomes easy. On the other hand, when the reading speed is high, the discharge speed is also increased, so that the leading edge of the document is easily dropped from the discharge tray 24, and in any case, the stackability of the discharged document is deteriorated.

However, discharge speed acceleration / deceleration control is applied to the controller 80 of the present invention.
Specifically, the discharge motor is installed separately from the reading motor, and the discharge roller 42 is driven separately from the reading rollers 36 and 37. Then, after the trailing end of the document has passed the reading roller 37, the discharge side adjustment unit 88 changes the discharge speed within a variable range of the reading speed with respect to the discharge side motor. When the set scanning speed is slow (for example, a mode that requires high image quality) with reference to the speed, the discharge speed is made faster than the slow scanning speed, while the set scanning speed is fast (for example, high-speed scan mode). Outputs a signal that makes the discharge speed slower than this fast reading speed.

  Therefore, simply changing the discharge speed freely with respect to the reading speed makes the discharge speed still slower and the trailing edge more likely to remain, despite the low reading speed (for example, high resolution), and Although the reading speed is high (for example, low resolution), the discharge speed is further increased and the sheet is more easily dropped from the discharge tray 24. The discharge speed does not reach a high scanning speed but can exceed the slow scanning speed, and an optimal discharge speed can be aimed at. The stackability of the will improve.

Further, the discharge tray 24 is formed so that sheets of discharged originals can be stacked in the thickness direction. The discharge speed by the discharge side adjustment unit 88 is increased or decreased as compared with the reading speed, and can be further increased or decreased in consideration of the state of the discharged document, so that the stackability of the discharged document can be further improved. .
Further, if a slow discharge speed is set when there are few discharged documents, the leading edge of the document sent from the discharge roller 42 hangs down and enters the inclined portion of the discharge tray 24 at a steep angle. Or the load when climbing the inclined portion of the discharge tray 24 becomes large, so that the document sent from the discharge roller 42 is folded immediately after being discharged, resulting in poor discharge. However, since the discharge-side adjustment unit 88 in this case increases the document discharge speed, the leading edge of the document sent from the discharge roller 42 enters at a gentle angle with respect to the inclined portion of the discharge tray 24. The load when climbing up the inclined portion is also reduced, so that it is possible to avoid the discharge failure and contribute to the improvement of stackability of the discharged document.

  Furthermore, if a high discharge speed is set when there are already a large number of discharged documents, the document sent from the discharge roller 42 jumps out of the apparatus main body 2 from the discharge tray 24, resulting in a discharge failure. However, since the discharge-side adjustment unit 88 in this case slows down the document discharge speed, the document sent from the discharge roller 42 does not jump out from the discharge tray 24 toward the outside of the apparatus body 2, and the discharged document The end faces can be more easily aligned, discharge defects can be avoided, and the stackability of discharged documents can be improved.

Further, if the discharge side adjustment unit 88 gradually decreases the document discharge speed in accordance with the number of discharged documents, the end surfaces of the discharged documents are more reliably aligned.
Further, since the stacking property of the discharged document is improved, the user's work period for the multifunction device 1 can be shortened, and the reliability of the multifunction device 1 is also improved.
The present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims.

For example, in the above embodiment, the state of the discharged document is detected by the counter 90, but the detection means of the present invention may be a sensor that can measure the height of the document loaded on the discharge tray 24. Further, assuming that a document on the discharge tray 24 is extracted during the discharge, a scale capable of measuring the weight of the document on the discharge tray 24 may be used.
An example of detection at the former discharge position will be specifically described. If the counter 90 measures, the height of a document corresponding to about 50 sheets (hereinafter referred to as a height near 50 sheets) is used as a reference. The discharge side adjustment unit 88 sets a discharge speed faster than the discharge speed E described above until the height of the document loaded on the discharge tray 24 reaches the height of the vicinity of the 50 sheets. This is because a discharge speed slower than the discharge speed E may be set when the height of the stacked originals exceeds the height of the vicinity of the 50 sheets.

  In the above-described embodiment, an example in which the image forming apparatus is embodied in a multifunction peripheral is shown. However, the present invention is naturally applicable to a copying machine, a printer, and the like having a document feeding device. In this case as well, as described above, there is an effect that the stackability of the discharged document is reliably improved while reducing the burden on the user.

1 MFP (image forming device)
7 Reading unit 20 Document feeding device 22 Document tray 24 Discharge tray 36, 37 Reading side roller 42 Discharge roller 80 Controller (control means)
86 Reading side adjustment unit 88 Discharge side adjustment unit 90 Counter (detection means)

Claims (8)

A document feeder that feeds a document conveyed from a document tray and whose image surface is read by a reading unit to a discharge tray by a discharge roller,
A reading side roller capable of conveying the original conveyed from upstream toward the discharge roller from the reading unit;
Reading-side drive means for driving the reading-side roller by changing it to a reading speed set for each reading mode;
Discharging side driving means that is installed separately from the reading side driving means and drives the discharging roller at a predetermined discharging speed;
A document feeding mechanism comprising: a control unit configured to change the discharge side driving unit within a variable range of the set reading speed after the trailing edge of the document has passed through the reading side roller. apparatus. The document feeder according to claim 1,
After the trailing edge of the document has passed through the reading side roller, the control means sets the discharging speed to the discharging side driving means when the set reading speed is slower than a predetermined reference speed. An original feeding device characterized in that the document feeding device is set to be faster than the slow reading speed, and when the set reading speed is faster than the predetermined reference speed, the discharge speed is made slower than the fast reading speed. The document feeder according to claim 1 or 2,
The document feeding device according to claim 1, wherein the control means makes the discharge speed after the trailing edge of the document passes the reading side roller substantially constant within the range of the reading speed. The document feeder according to any one of claims 1 to 3,
Further comprising detection means for detecting the state of the document sent to the discharge tray;
The document feeder according to claim 1, wherein the controller further changes the discharge speed in accordance with a detection result of the detector. The document feeder according to claim 4,
The detecting means is a counter for measuring the number of documents sent to the discharge tray;
The control means makes the discharge speed faster than the value obtained from the relationship with the reading speed with respect to the discharge side drive means when the number of originals by the counter is small. Document feeder. The document feeder according to claim 4 or 5,
The detecting means is a counter for measuring the number of documents sent to the discharge tray;
The control means makes the discharge speed slower than the value obtained from the relationship with the reading speed with respect to the discharge side drive means when the number of documents by the counter is large. Document feeder. The document feeder according to claim 4 or 5,
The detecting means is a counter for measuring the number of documents sent to the discharge tray;
The control means causes the discharge speed to be gradually made slower than the value obtained from the relationship with the reading speed with respect to the discharge side drive means in proportion to an increase in the number of documents by the counter. A document feeder characterized by its characteristics.   An image forming apparatus comprising the document feeder according to claim 1.

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