JPH06321383A - Sheet material transfer device, and sheet material feeding device - Google Patents

Abstract

PURPOSE:To transfer a corrugated sheet material separated by a pair of separation rollers under the condition that any wrinkle is not caused. CONSTITUTION:The contact pressure of a drive roller 22A and a driven roller 22B as a pair of transfer rollers 22 which are located just on the downstream side from a pair of separation rollers 10 is varied according to the thickness of a sheet material S by a contact pressure varying mechanism 21. The contact pressure varying mechanism 21 is interlocked with a mechanism which adjusts the overlapped amount of a large diameter part of rollers 10A and 10B as the pair of separation rollers 10. When a cam shaft 16 is rotated clockwise, the exciting force of an exciting spring 27 to excite the driven roller 22B is increased (contact pressure is large) and, when it is rotated counterclockwise, the exciting force of the exciting spring 27 is reduced (contact pressure is small).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The first and third inventions are
The present invention relates to a sheet material conveying device provided in an image reading device or the like.

A second invention relates to a sheet material feeding device provided in an image reading device or the like.

[0003]

[Prior art]

<Prior Art 1> FIG.
As shown in FIG. 1, as a means for separating the sheet materials S fed from the stacking section one by one, a pair of separation rollers 110, 1
11 is used.

The separating roller pairs 110 and 111 rotate the upper roller 110, which has a large frictional force on the sheet material S, in the sheet material conveying direction (forward direction), and reverses the lower roller 111, which has a small frictional force on the sheet material S. By rotating in the sheet material transport direction (reverse direction), only the topmost sheet is
It is designed to separate sheets.

Further, the upper roller 110 and the lower roller 11
As shown in FIG. 9, 1 is a plurality of large diameter parts 110A, 11A.
1A and small diameter portions 110B and 111B are alternately formed, and the large diameter portions 110A and 111A and the small diameter portion 110 are mutually formed.
B and 111B are arranged to face each other.

In this case, the amount of overlap between the large diameter portion 110A of the upper roller 110 and the large diameter portion 111A of the lower roller 111 is changed according to the thickness of the sheet material S.

The sheet material S separated by the pair of separating rollers 110 and 111 is conveyed to a predetermined downstream position by the pair of conveying rollers 112 and 113. <Prior Art 2> In a sheet material feeding device such as an image reading device, as shown in FIG. 23, a sheet material loading device using a common feeding roller 212 is capable of continuous sheet feeding and manual sheet feeding. Some include a table 201.

In such a sheet material feeding device, the sheet material mounting table 201 is commonly used for continuous sheet feeding and manual sheet feeding.
Can swing up and down around the support shaft 201A as the center of rotation.

When the sheet material placing table 201 manually feeds the sheet material one by one using the feeding roller 212, as shown in the figure, the supporting shaft is placed in a substantially horizontal state. It is held by a holding lever 202 which is rotatable about 203 as a rotation center.

When the leading edge of the sheet material is placed on the sheet material mounting table 201 in this posture and fed in the direction of the arrow, the sheet material is fed by the feeding roller 212 rotating in the direction of the arrow, and then rotated in the direction of the arrow. It passes through the separation roller pair 213.

Here, when the leading edge of the sheet material placed on the sheet material mounting table 201 is fed in the direction of the arrow, the feeding roller 21
2, the sheet material detection levers 209 and 21 located immediately upstream of
0 is pushed up by the leading edge of the sheet material and rotates counterclockwise around the support shaft 211 as a rotation center. By the movement of the sheet material detection levers 209 and 210, the sheet material detection means 218
Detects that the sheet material has been fed.

When the sheet material detecting means 218 detects the sheet material, the clutch (not shown) is turned on, and the feeding roller 212 and the upper roller (feed roller) 2 of the separating roller pair 213 are turned on.
13A rotates in conjunction with the sheet material conveying direction (arrow direction).

The lower roller (retard roller) 213B of the separation roller pair 213 always rotates in the counter sheet material conveying direction (arrow direction) after the power is turned on.

Further, when the sheet material placing table 201 continuously feeds a large number of sheet materials stacked by using the feeding roller 212, the holding state by the holding lever 202 is released and the spindle 201A is released. It is in a state of free rocking around.

At this time, the front end (free end) 201C of the sheet material mounting table 201 contacts the horizontal end portion 215A of the guide member 215 and its downward movement is restricted. The sheet material stacked on the sheet material mounting table 201 is always brought into contact with the feeding roller 212 at a predetermined pressure by the push-up lever 204 which rotates upward about the support shaft 205 as a rotation center.

A predetermined sliding resistance force is applied by the friction member 307 between the lowermost sheet of the sheet material stacked on the sheet material placing table 201 and the sheet material placing table 201, and the lowermost sheet is placed. Is prevented from being fed integrally with the upper sheet material (double feed).

When the sheet material stacked on the sheet material mounting table 201 is fed by the feeding roller 212 rotating in the arrow direction, it is sent to the nip portion of the separating roller pair 213 rotating in the arrow direction.

When a plurality of sheet materials are fed to the nip portion of the separation roller pair 213, the sheet materials other than the uppermost sheet are moved by the lower roller 213B which rotates in the direction opposite to the sheet material transporting direction. The uppermost sheet is returned to the upper side, and only the uppermost sheet is sent to the downstream side by the upper roller 213A which rotates in the sheet material conveying direction.

In the case of continuous feeding, the clutch (not shown) is turned on by the input of the start signal, and the feeding roller 21
2 and the upper roller 213A of the separation roller pair 213 rotate in conjunction with the sheet material conveyance direction. Separation roller pair 213
The lower roller 213B always rotates in the direction opposite to the sheet material conveyance direction after the power is turned on.

In such a sheet material feeding device,
Conventionally, as a means for preventing the entire movement of the sheet material stacked on the sheet material mounting table 201 during continuous sheet feeding, the sheet material mounting table 201 is attached via a leaf spring 306 and the sheet material mounting table 201 is mounted. A thin plate-shaped friction member 307 located on the upper surface of the table 201 is used.

The friction member 307 is used for the second sheet material placement second.
When 01 is in the manual feed position as shown in the figure, it is in contact with the feeding roller 212 at a predetermined pressure by the urging force of the leaf spring 306.

Reference numeral 201B in FIG. 23 indicates a sheet material mounting table so that the edge portion of the sheet material is not caught on the edge portion of the friction member 307 which is in contact with the feeding roller 212 during manual feeding. It is a guide formed on a part of 201. <Prior Art 3> An image reading device or the like is provided with a pair of registration rollers for correcting a skewed state of a conveyed sheet material in a sheet material conveyance path.

In the image reading apparatus, a registration roller pair is arranged in the sheet material conveying path upstream of the image reading unit,
After the skewed state of the sheet material is corrected by the pair of registration rollers, the image of the sheet material is read by the image reading unit.

FIG. 34 shows the overall construction of a conventional image reading apparatus.

From the upstream side, the sheet material placing table 401, the feeding roller 405, the separating roller pair 406, and the conveying roller pair 40.
7, registration roller pair 408, image reading unit 409,
A paper discharge roller pair 424 and a paper discharge tray 426 are sequentially arranged.

In the present image reading apparatus, the sheet material S stacked on the sheet material mounting table 401 is separated by the feed roller 405 which rotates in the sheet material conveying direction to form a pair of separation rollers 4.
It is sent to the nip part of 06. At this time, the sheet material S
Is guided to the upper guide 403 and the lower guide 404.

Here, the sheet material mounting table 401 is provided on the support shaft 4.
01A is swingable in the vertical direction about the rotation center, and is pushed upward by the push-up spring 402 so that the sheet material S contacts the feeding roller 405 with a predetermined pressure.

When a plurality of sheet materials S are fed to the nip portion by the separation roller pair 406, the sheet materials S other than the uppermost sheet are moved by the lower retard roller 406B which rotates in the direction opposite to the sheet material conveying direction. Back on 401,
Only the uppermost sheet is sent to the nip portion of the downstream transport roller pair 407 by the upper feed roller 406A that rotates in the sheet transport direction. At this time, the separation sheet material S is guided to the upper guide 403 and the lower guide 404.

The sheet material S fed into the nip portion of the conveying roller pair 407 is fed downstream by the conveying roller pair 407 into the nip portion of the resist roller pair 408 whose rotation is stopped. At this time, the sheet material S is guided to the upper guide 410 and the lower guide 411.

The sheet material S transported by the transport roller pair 407 is a sheet material detection sensor (photointerrupter) 427 installed immediately upstream of the registration roller pair 408.
Detected by. Then, the sheet material detection sensor 42
When 7 detects the leading edge of the sheet material S, the registration roller pair 408, which has stopped rotating after a predetermined time, rotates in the sheet material conveyance direction.

Between the detection of the leading edge of the sheet S by the sheet material detection sensor 427 and the start of rotation of the registration roller pair 408 (within a predetermined time), the pair of conveyance rollers 407.
Register roller pair 40 that is conveyed by and stops rotating
A loop for correcting the skewed state is formed on the sheet material S that has abutted against the nip portion of No. 8.

The sheet material S whose skewed state has been corrected is sent to the image reading section 409 located downstream by the registration roller pair 408, and the images on both sides of the sheet material are read.

The image reading unit 409 includes an upper image reading unit 409A for reading an image on the upper surface of the sheet material and a lower image reading unit 409B for reading an image on the lower surface of the sheet material.

The upper image reading unit 409A is a reflection lamp which guides the illumination lamp 416 for illuminating the upper surface of the sheet material through the transparent portion 414A of the upper reading guide 414 and the image light X reflected vertically on the upper surface of the sheet material in the horizontal direction. A mirror 418,
An imaging lens 420 that transmits the image light X reflected by the reflection mirror 418 to form an image, and the imaging lens 420
The image reading sensor 412, such as a CCD element, which converts the image light X formed by the above into an electric signal.

The lower image reading section 409B is a lighting lamp 417 for illuminating the lower surface of the sheet material via the transparent portion 415A of the lower reading guide 415, and a reflection for guiding the image light Y reflected vertically on the lower surface of the sheet material in the horizontal direction. A mirror 419,
From an image forming lens 421 that transmits the image light Y reflected by the reflection mirror 419 to form an image, and an image reading sensor 423 such as a CCD element that converts the image light Y formed by the image forming lens 421 into an electric signal. Become.

The sheet material S from which the image has been read by the image reading section 409 is discharged onto a sheet discharge tray 426 by a pair of sheet discharge rollers 424 which rotate in the sheet material conveying direction.

In the above-mentioned image reading apparatus, the driving roller 407A and the driven roller 407B of the conveying roller pair 407.
Is a cylindrical roller having a constant width in the width direction of the sheet material S.

The driving roller 408A and the driven roller 408B of the registration roller pair 408 convey the sheet material S to the image reading unit 409 without slipping, so that a predetermined frictional force is obtained between the sheet material S and the sheet material S. It is said to be a rubber roller.

In the present image reading apparatus, by inputting a start signal, the feeding roller 405, the feed roller 406A and the retard roller 406B of the separation roller pair 406, and the driving roller 407 of the conveyance roller pair 407.
A, the driving roller 424A of the paper discharge roller pair 424 is simultaneously driven to rotate in the arrow direction.

[0040]

[Problems to be Solved by the Invention]

<Problem of the First Invention> However, the separation roller pair 110 and 111 shown in the above-mentioned prior art 1 has the upper roller 11 thereof.
0 and the lower roller 111 have a plurality of large-diameter portions 110A, 111
Since A and the small-diameter portions 110B and 111B are included, the sheet material (separation sheet material) S sandwiched between the upper roller 110 and the lower roller 111 is wavy as shown in FIG. 9 along the sheet material conveying direction. Will end up.

Therefore, when the sheet material S is conveyed by the conveying roller pairs 112 and 113 in the next stage, there is a problem that a plurality of wrinkles are likely to occur in the sheet material conveying direction. In particular, in the case of the thin sheet material S having a weak stiffness, the occurrence rate of wrinkles is high.

Therefore, the first invention is made in view of the above-mentioned circumstances, and even if the sheet material separated by the pair of separating rollers is corrugated, the sheet material is conveyed without wrinkling. An object of the present invention is to provide a sheet material conveying device capable of performing the above. <Problem of the Second Invention> However, in the conventional sheet material feeding device shown in the above-mentioned Prior Art 2, when a thin thin sheet material having a weak stiffness is manually fed, the feeding roller 212 is predetermined. Due to the thin plate-shaped friction member 307 that is in contact with the pressure, there is a problem that the leading edge of the sheet material cannot be fed between the feeding roller 212 and the sheet material mounting table 201.

For example, as shown in FIG. 24, the sheet material S
When the leading edge SA of the sheet material strikes the feeding roller 212 and is pushed down, the leading edge SA of the sheet material S is curved and is caught by the friction member 307.

Further, as shown in FIG. 25, when the leading edge of the sheet material S cannot push up the sheet material detection lever 209, the leading edge SA of the sheet material S buckles and is caught by the friction member 307.

As described above, when the leading edge SA of the sheet material S is curved or buckled and is caught by the friction member 307,
It becomes difficult to feed the leading edge SA of the sheet material S between the feeding roller 212 and the sheet material placing table 201, and the feeding material 212 cannot feed the sheet material S.

Therefore, the second invention is made in view of the above-mentioned circumstances, and a sheet which can be reliably fed by a feeding roller even if it is a thin sheet material having a weak stiffness during manual feeding. An object is to provide a material feeding device. <Problem of the Third Invention> However, like the image reading apparatus of the conventional example shown in the above-mentioned conventional technique 3, rubber rollers are used for the driving roller 408A and the driven roller 408B of the registration roller pair 408, and the registration roller is used. The sheet material S is fed to the driving roller 407A and the driven roller 407B of the conveying roller pair 407 that feeds the sheet material S to the nip portion of the pair 408.
When a cylindrical roller having a constant width in the width direction of the sheet is used, the sheet material S transported by the transport roller pair 407 is used.
In some cases, the skew feeding cannot be corrected by the registration roller pair 408.

That is, in order to correct the skewed state of the sheet material S by the registration roller pair 408, the leading edge of the sheet material correctly abuts on the nip portion of the registration roller pair 408, and in this state, a predetermined loop is formed on the sheet material S. It must be.

When the leading edge of the sheet material hits the nip portion of the registration roller pair 408 and a predetermined loop is formed on the sheet material S, the action of the loop causes the entire leading edge of the sheet material to hit the nip portion of the registration roller pair 408 and the sheet. Material S
The skewed condition of is corrected.

However, when the driving roller 408A and the driven roller 408B of the registration roller pair 408 are rubber rollers, the tip of the sheet material cannot enter the nip portion due to the frictional force of the rubber roller, and a loop is formed in the sheet material S. There is.

Therefore, the leading edge of the sheet material S is not aligned with the nip portion, and the skewed state cannot be corrected.

Further, particularly in the case of a thin and weak sheet material S, the leading edge is apt to be caught on the registration roller surface, so that the leading edge of the sheet is not properly aligned with the nip portion of the registration roller. There was also a problem that wrinkles were formed on the surface.

Therefore, the third invention is made in view of the above-mentioned circumstances, and is a thin and weak sheet material which can surely correct the skewed state of the sheet material by the pair of registration rollers. Another object of the present invention is to provide a sheet material conveying device in which wrinkles do not occur at the tip of the sheet material during skew correction.

[0053]

[Means for Solving the Problems]

<Means of First Invention> A first invention is a pair of separating rollers (1
0) is a sheet material conveying device for conveying the sheet material (S) separated one by one to a predetermined downstream position by using an appropriate number of conveying roller pairs (22).

In order to achieve the above object, the first aspect of the present invention is to provide the rollers (22A, 22A) of the conveying roller pair (22) arranged immediately downstream of the separating roller pair (10).
It is characterized by having a contact pressure changing means (21) for changing the contact pressure of B) according to the thickness of the sheet material (S). <Means of Second Invention> A second invention is a sheet material provided with a sheet material mounting table (201) capable of connecting paper feeding using a common feeding roller (212) and manual paper feeding. Related to the feeding device.

In order to achieve the above object, the second aspect of the present invention provides a predetermined gap between the sheet material mounting table (201) and the sheet material when the sheet material mounting table (201) is in a continuous feeding mode. When the sheet material placing table (201) is in a manual feeding state, the sliding material force is not provided between the sheet material placing table (201) and the sheet material. Sliding resistance means (20
7) The sheet material feeding device characterized by having. <Means of Third Invention> A third invention is a pair of registration rollers for correcting the skewed state of the sheet material (S), and a pair of conveyance rollers for conveying the sheet material (S) to the registration roller pair (408). (407), and a sheet material conveying device including:

In order to achieve the above-mentioned object, the third aspect of the present invention uses the conveying roller pair (407) as a cylindrical driven roller (407B) having a constant width in the width direction of the sheet material (S). And a drive roller (407C) having a shape that makes partial contact with the driven roller (407B) intermittently.

[0057]

[Action]

<Operation of the First Invention> According to the sheet material conveying device of the first invention having the above-described configuration, each roller (22) of the conveying roller pair (22) arranged immediately downstream of the separation roller pair (10).
The contact pressure of A, 22B) is changed by the contact pressure changing means (21) so as to be the contact pressure according to the thickness of the sheet material (S).

For example, when a thin sheet material (S) is used, the contact pressure changing means (21) has a pair of conveying rollers (2).
When the contact pressure of each roller (22A, 22B) in 2) is made small and a thick sheet material (S) is used, the contact pressure changing means (21) uses the contact pressure changing means (21) for each roller (2) of the conveying roller pair (22).
2A, 22B) contact pressure is increased.

Therefore, the pair of conveying rollers (22) pinch and convey the sheet material (S) separated by the pair of separating rollers (10) with a contact pressure corresponding to its thickness.

That is, when the sheet material (S) separated by the separation roller pair (10) is a thin sheet material,
The conveying roller pair (22) nips and conveys the sheet material (S) with a weak contact pressure, and when the sheet material (S) is thick, the conveying roller pair (22) presses the sheet material (S) with a strong contact pressure. Hold and transport.

As a result, even if the sheet material (S) separated by the separation roller pair (10) is wavy,
Plural wrinkles do not occur in the sheet material conveying direction due to the contact pressure of each roller (22A, 22B) of the conveying roller pair (22) that conveys the sheet material (S). <Operation of the Second Invention> According to the sheet material feeding device of the second invention having the above-mentioned configuration, when the sheet material mounting table (201) is in the continuous feeding state, the sliding resistance means (207) causes the sheet to move. A state in which a predetermined sliding resistance is applied between the material placing table (201) and the sheet material is achieved. Also, a sheet material mounting table (201)
When the sheet is ready to be manually fed, the sliding resistance means (207) does not apply a sliding resistance force between the sheet material mounting table (201) and the sheet material.

Therefore, when the sheet material is manually fed,
The sliding resistance means (207) does not obstruct the leading edge of the sheet material fed between the sheet feeding roller (212) and the sheet material mounting table (201).

As a result, even when a thin and weak sheet material is manually fed, the leading edge of the sheet material can be reliably fed between the feeding roller (212) and the sheet material placing table (201). The sheet material can be fed without any trouble. <Operation of the third invention> According to the sheet material conveying device of the third invention having the above-mentioned configuration, the cylindrical driven roller (407B) having a constant width in the width direction of the sheet material (S), The sheet material (S) is conveyed to the registration roller pair (408) by a conveying roller pair (407) including a driving roller (407C) having a shape that intermittently makes partial contact with the driven roller 8407B) to form a loop. . However, when the loop reaches a certain amount, the sheet material (S) is pushed back in a direction in which the loop becomes smaller when the driving roller comes into non-contact with the driven roller due to the waist of the sheet. Then, when the driving roller comes into contact with the driven roller, the loop is formed again. In this way, the drive roller repeats the non-contact state and the contact state with the driven roller to repeat the loop formation. That is, the abutting operation of the sheet material (S) to the nip portion of the registration roller pair is repeated.

Thus, even if a loop is formed without the leading edge of the sheet material (S) entering the nip portion of the registration roller pair (408), the abutting operation of the registration roller pair against the nip portion is repeated. The skewed state of the sheet material (S) can be corrected.

The reference numerals in parentheses refer to the drawings and do not limit the structure of the invention.

[0066]

Embodiments of the first, second and third inventions will be described below with reference to the drawings. <Embodiment 1 of the first invention> FIG. 1 shows Embodiment 1 of the first invention.
FIG. 6 is a vertical cross-sectional side view showing an overall configuration of an image reading apparatus including the sheet material conveying device according to the first embodiment.

FIG. 2 is a vertical sectional side view showing a detailed structure of a main part (invention part) of the image reading apparatus, and FIG. 3 is a plan view thereof.

First, the overall structure of the image reading apparatus will be described along the flow of the sheet material.

The sheet material S stacked on the sheet material mounting table 1 is sent to the nip portion of the separation roller pair 10 by the feeding roller 5.

The sheet material S sent to the nip portion of the separation roller pair 10 is separated one by one by the separation roller pair 10 and sent to the nip portion of the conveyance roller pair 22.

The sheet material S sent to the nip portion of the conveying roller pair 22 is sent to the nip portion of the registration roller pair 51 whose rotation is stopped by the conveying roller pair 22.

At this time, the sheet material detecting sensor 23 installed immediately upstream of the registration roller pair 51 detects the leading edge of the sheet material. When the sheet material detection sensor 23 detects the leading edge of the sheet material, the registration roller pair 51, which has stopped rotating after a predetermined time, rotates.

During the period from the detection of the leading edge of the sheet material to the start of rotation of the registration roller 51 (within a predetermined time), the leading edge of the sheet material S transported by the transport roller pair 22 is the nip of the registration roller pair 51 whose rotation is stopped. A predetermined loop is formed at the portion to correct the skewed state.

The sheet material S whose skewed state has been corrected is sent by the registration roller pair 51 between the reading upper guide 57 and the reading lower guide 56, and the images on the upper and lower surfaces of the sheet material are read there.

At the time of reading the image, the sheet material S is held by the registration roller pair 51 and the conveying roller pair 53 at the next stage without slack, and is conveyed at a constant speed.

The image on the upper surface of the sheet material is the upper image reading unit 5.
2A, and the image on the lower surface of the sheet material is read by the lower image reading unit 52B.

The upper image reading unit 52A includes an illumination lamp 55 that illuminates the upper surface of the sheet material through the transparent portion 57A of the upper reading guide 57, and a reflection mirror that guides the image light vertically reflected on the upper surface of the sheet material in the horizontal direction. 59, an image forming lens 61 for transmitting the image light reflected by the reflecting mirror 59 to form an image, and an image reading sensor 63 such as a CCD element for converting the image light formed by the image forming lens 61 into an electric signal.
Consists of.

The lower image reading unit 52B illuminates the lower surface of the sheet material via the transparent portion 56A of the lower reading guide 56, and the reflection mirror 58 which guides the image light horizontally reflected on the lower surface of the sheet material in the horizontal direction. And the reflection mirror 5
An image forming lens 60 that transmits the image light reflected by 8 to form an image, and an image reading sensor 62 such as a CCD element that converts the image light formed by the image forming lens 60 into an electric signal.

The sheet material S, from which the image has been read, is conveyed downstream by the upper and lower conveyor belts 76 and 77, and is ejected outside the apparatus by the ejection rollers 78.

Reference numeral 80 in FIG. 1 is a recording device for recording an image converted into an electric signal by an image reading sensor 62 such as a CCD element on a recording medium such as a magneto-optical disk.
Reference numeral 81 is a display device for displaying an image converted into an electric signal by the image reading sensor 62 such as a CCD element or an image recorded on a recording medium such as a magneto-optical disk, and reference numeral 82 is a transmission section.

Next, the structure of the main part of the image reading apparatus will be described with reference to FIGS.

The sheet material mounting table 1 can be vertically swung about the spindle 1A as a rotation center. The sheet material mounting table 1 is pushed up by a push-up lever 2 rotatable about a support shaft 2B, and when pushed up by the push-up lever 2 (state of FIG. 2), the sheet material mounting table 1 is pushed. The sheet material S stacked on the sheet 1 comes into contact with the feeding roller 5 at a predetermined pressure.

The push-up lever 2 is constantly urged by the urging spring 17 in the direction of pushing up the sheet material mounting table 1. Then, such a push-up lever 2 is provided with the rotary shaft 4
When the cam 4 mounted on A is rotated from the position shown by the solid line in FIG. 1 to the position shown by the imaginary line in FIG. 1, the cam 4 is rotated (moved down) against the biasing spring 17 to the position shown by the imaginary line.

In this way, when the push-up lever 2 is rotationally moved by the cam 4, the sheet material mounting table 1 is supported by the support shaft 1A.
The sheet material S on the sheet material mounting table 1 is separated from the feeding roller 5 by swinging downward about the rotation center, and the sheet cannot be fed.

When the sheet material S on the sheet material mounting table 1 is fed by the feeding roller 5, the cam 4 is rotated to the position shown by the solid line. By doing so, the sheet material mounting base 1 is pushed up by the push-up lever 2 and swings upward, and the sheet material S on the sheet material mounting base 1 contacts the feeding roller 5.

The push-up lever 2 for pushing up the sheet material mounting table 1 is usually at the position shown in the phantom line (home position).
The sheet material mounting table 1 is not pushed up by the cam 4 in FIG.

The push-up lever 2 pushes up the sheet material mounting table 1 when the cam 4 is rotated from the position shown by the phantom line to the position shown by the solid line when the power is turned on.

When the sheet material placing table 1 is pushed up by the push-up lever 2, the presence or absence of the sheet material S stacked on the sheet material placing table 1 is detected by the sheet material detecting sensor (photo interrupter) 7.

The sheet material detection sensor 7 detects the presence / absence state of the sheet material S on the sheet material mounting table 1 through the detection lever 6 which comes into contact with the sheet material S on the sheet material mounting table 1.

That is, when the L-shaped detection lever 6 rotatable about the support shaft 6A is in contact with the sheet material S on the sheet material mounting table 1 (state in FIG. 2),
One end 6B of the detection lever 6 blocks the light from the sheet material detection sensor 7, and the sheet material detection sensor 7 detects the presence of the sheet material.

When the detection lever 6 is not in contact with the sheet material S on the sheet material mounting table 1, one end 6B of the detection lever 6 is in a state of not blocking the light of the sheet material detection sensor 7, and the sheet material detection sensor 7 is Detects the absence of sheet material.

When the sheet material placing table 1 is pushed up by the push-up lever 2 and the sheet material detecting sensor 7 detects the sheet material S on the sheet material placing table 1, the sheet feeding roller 5 and the separation roller are separated through a clutch (not shown). The rotation in the sheet material conveying direction is transmitted to the feed roller 10A of the pair 10, and the feeding of the sheet material S on the sheet material mounting table 1 is started.

Here, when the power is turned on, the rotation in the anti-sheet material conveying direction is transmitted to the retard roller 10B of the separating roller pair 10, and the driving roller 22A of the conveying roller pair 22 is transmitted.
Similarly, the rotation in the sheet material conveying direction is transmitted when the power is turned on. Further, the driven roller 22B of the pair of conveying rollers 22 comes into contact with the driving roller 22A and is driven to rotate in the sheet material conveying direction.

The rotation of the main motor (not shown) is transmitted to the feed roller shaft gear 8A of the feed roller 10A via a clutch (not shown).
Is transmitted to the feeding roller shaft gear 8C of the feeding roller 5 via the gear 8B. Here, the feed roller 10A
Is attached to the feed roller shaft 8 via a one-way rotation clutch 9 and rotates in the sheet material conveying direction.

The rotation of the main motor is driven by the drive roller 2
The rotation of the drive roller shaft 26 is transmitted to the drive roller shaft gear 43 of 2A, and is transmitted to the retard roller shaft 11 of the retard roller 10B via the gears 38, 37, 35 and 33.

The feed roller shaft 8 of the feed roller 10A and the drive roller 26 of the drive roller 22A are rotatably attached to predetermined positions of the image reading apparatus main body (not shown).

The retard roller shaft 11 of the retard roller 10B is rotatably attached to a bracket 14 having a U-shaped cross section which is attached to the drive roller shaft 26 of the drive roller 22A so as to be vertically swingable.

The bracket 14 is biased by a biasing spring 19 in a direction (clockwise direction) in which the retard roller 10B contacts the feed roller 10A. Biasing spring 19
Is interposed between the projection 14A provided at one end of the bracket 14 and the main body of the image reading apparatus.

In the bracket 14, when the cam 15 that abuts the bent portion 14B formed at one end of the bottom wall of the bracket 14 is rotated, the bracket 14 swings up and down about the drive roller shaft 26. By swinging the bracket 14 in the vertical direction by the cam 15, the axial distance between the feed roller 10A and the retard roller 10B can be changed.

When the cam 15 is rotated clockwise, the axial distance between the feed roller 10A and the retard roller 10B is increased, and when the cam 15 is rotated counterclockwise, the feed roller 10A and the retard roller 10B are rotated. The inter-axis distance between them becomes smaller.

Therefore, by rotating the cam 15 clockwise or counterclockwise by a predetermined amount, as shown in FIG.
The overlap amount d between the large diameter portions 10A-1 and 10B-1 of the feed roller 10A and the retard roller 10B can be adjusted to an amount according to the thickness of the sheet material S. When the sheet material S is thick, the overlap amount d is reduced, and when the sheet material S is thin, the overlap amount d is increased.

The cam 15 for swinging the bracket 14 in the vertical direction is rotated clockwise or counterclockwise by a knob 28 provided on the outer end of the cam shaft 16. Knob 28
Is arranged outside the main body of the image reading apparatus.

An operation plate 18 having an arcuate guide groove 18A is fixed on the cam shaft 16. A pin 20A of a slide member 20 installed in the image reading apparatus main body is engaged with the guide groove 18A of the operation plate 18 so as to be movable only in the vertical direction.

The driven roller shaft 30 of the driven roller 22B is
A feed roller shaft 8 of the feed roller 10A is rotatably attached to a bracket 29 having a U-shaped cross section which is attached so as to be vertically swingable.

The bracket 29 is urged by an urging spring (coil spring) 27 in a direction (clockwise direction) in which the driven roller 22B contacts the drive roller 22A. The biasing spring 27 is interposed between the pin 31 provided on one side of the bracket 29 and the pin 20B provided on the slide member 20.

Therefore, by changing the biasing force (tension) of the biasing spring 27, the driven roller 22B and the driving roller 22 are
The contact pressure with A can be adjusted. The adjustment of the contact pressure between the driven roller 22B and the drive roller 22A can be performed in conjunction with each other by adjusting the overlap amount d of the feed roller 10A and the retard roller 10B described above.

Here, the cam shaft 16, the operating plate 18, the slide member 20, the biasing spring 27, and the bracket 29 constitute a contact pressure changing mechanism 21.

That is, when the sheet material S is thick, the overlap amount d between the feed roller 10A and the retard roller 10B is reduced. For this reason, when the cam 28 is rotated clockwise by the knob 28 by a predetermined amount, the cam shaft 16
By the action of the operation plate 18 that rotates integrally with the urging spring 2 (the pin 20A moves downward along the guide groove 18A).
The slide member 20 supporting one end of 7 moves downward. Therefore, the urging spring 27 expands and its urging force is strengthened, and the contact pressure between the driven roller 22B and the drive roller 22A increases.

When the sheet material S is thin, the overlap amount d between the feed roller 10A and the retard roller 10B is increased. For this reason, when the cam 28 is rotated counterclockwise by the knob 28 by a predetermined amount, the operating plate The slide member 20 moves upward by the action of 18 (the pin 20A moves upward along the guide groove 18). For this reason,
The urging spring 27 contracts and its urging force is weakened, and the contact pressure between the driven roller 22B and the drive roller 22A becomes low.

As described above, when the sheet material S is thick, the contact pressure between the driven roller 22B and the driving roller 22A is increased,
When the sheet material S is thin, the contact pressure between the driven roller 22B and the drive roller 22A is reduced, so that the separation roller pair 1
When the sheet material S that is wavy at 0 is conveyed,
A plurality of wrinkles does not occur on the sheet material S in the sheet material conveyance direction, and the sheet material S is smoothed.

That is, in the case of a thin sheet material S, since the contact pressure between the driven roller 22B and the driving roller 22A is low,
Even when the corrugated sheet material S is sandwiched by both rollers 22B and 22A, the corrugated portion of the sheet material S can escape in the roller axial direction.

Further, since the thick sheet material S is stiff, even if the contact pressure between the driven roller 22B and the drive roller 22A is somewhat high, the corrugated portion of the sheet material S sandwiched between the rollers 22B and 22A is a roller. Can escape axially.

When the contact pressure between the driven roller 22B and the driving roller 22A is lowered, the conveying force of the conveying roller pair 22 is reduced, but in the case of the thin sheet material S, the guide plate 2 has a weak stiffness.
The resistance received from 4, 25 and the like is small, and therefore, the conveyance is not impossible.

Further, in the case of the thick sheet material S, since it is stiff, the resistance received from the guide plates 24, 25, etc. is large. For this reason, a large carrying force is required for the carrying roller pair 22, but since the contact pressure between the driven roller 22B and the driving roller 22A is increased, carrying is not impossible.

The magnitude of the contact pressure between the driven roller 22B and the driving roller 22A with respect to the thickness of the sheet material S depends on the overlap amount d between the feed roller 10A and the retard roller 10B, the driven roller 22B with respect to the sheet material S,
It is appropriately set in consideration of the frictional force of the drive roller 22A.

Here, the driven roller 22B and the drive 22A
Has a roller length capable of sandwiching the sheet material S including the corrugated area (area a shown in FIG. 5) of the sheet material S generated in the feed roller 10A and the retard roller 10B.

The rotation of the drive roller 22A is controlled by the gear 3
It is transmitted to the driven roller 22B via the rollers 2 and 34, and the conveying force of the conveying roller pair 22 is increased. In this case, the pitch circle diameter of the gear 32 is adjusted to the outer diameter of the drive roller 22A, and the gear 34
The pitch circle diameter is adjusted to the outer diameter of the driven roller 22B. The gears 32 and 34 mesh with each other so as not to interfere with the adjustment of the contact pressure between the driven roller 22B and the drive roller 22A.

When the leading edge of the sheet material S conveyed by the conveying roller pair 22 is detected by the sheet material detecting sensor (photo interrupter or the like) 23 arranged immediately downstream of the conveying roller pair 22, the feeding roller 5 and the feed roller 5 are fed. The clutch transmitting the rotation to the roller 10A is disengaged.

From this point onward, the feeding roller 5 and the feed roller 10A are rotated together with the sheet material S conveyed by the conveying roller pair 22, but when the sheet material S passes through the feeding roller 5 and the feed roller 10A, the rotation is sequentially stopped. To do. Therefore, the second and subsequent sheet materials S are not fed.

When the trailing edge of the sheet material S being transported by the transport roller pair 22 is detected by the sheet material detection sensor 23, the clutch for transmitting the rotation to the feeding roller 5 and the feed roller 10A operates again, The next sheet material S is fed.

In this way, when the sheet material S on the sheet material mounting table 1 is sequentially fed and the sheet material S on the sheet material mounting table 1 is exhausted, it contacts the sheet material S on the sheet material mounting table 1. The detection lever 6 that has been operated falls to the notch (not shown) of the sheet material mounting table 1, and the sheet material detection sensor 7 detects the absence of the sheet material.

When the sheet material detecting sensor 7 detects the absence of the sheet material, the cam 4 at the position shown by the solid line rotates to the position shown by the imaginary line, the push-up lever 2 is released, and the sheet material placing table 1 descends. To do. <Second Embodiment of First Invention> FIG. 6 shows a second embodiment of the first invention.
FIG. 3 is a vertical cross-sectional side view showing the configuration of the sheet material conveying device according to the present invention.

In describing the present sheet material conveying device, the sheet material conveying device of the first embodiment (FIGS. 2 and 3).
The same members and the like are designated by the same reference numerals, and the description of those that are structurally and functionally unchanged will be omitted.

In this sheet material conveying device, when the sheet material S enters the nip portion of the conveying roller pair 22, the thickness of the sheet material S is detected and the contact pressure between the driving roller 22A and the driven roller 22B is A contact pressure changing mechanism 90 that automatically changes the contact pressure according to the thickness of the sheet material S is provided.

The contact pressure changing mechanism 90 includes a displacement sensor 92 for detecting the thickness of the sheet material S and a driven roller 22B.
An urging spring (coil spring) 93 for urging the drive roller 22A, a slide member 94 for changing the urging force (tension) of the urging spring 93, and a vertical movement of the slide member 94. A forward / reverse rotatable motor (pulse motor) 95 and a home position sensor 96 for detecting the home position position of the slide member 94.
A limit sensor 98 for detecting the lowest point position of the slide member 94, and a CP for controlling the motor 95.
And U100.

The displacement sensor 92 is installed near the tip of a displacement amount amplification arm 91 extending from one end of the bracket 29. Then, the actuator 92A contacts the displacement amount amplification arm 91 to detect the displacement amount of the displacement amount amplification arm 91.

Here, the driven roller 2 of the conveying roller pair 22.
2B is attached to a bracket 29 which can be vertically swung about the feed roller shaft 8 as a center of rotation. Therefore, when the sheet material S enters the nip portion of the pair of transport rollers 22, the thickness of the sheet material S is reduced. Accordingly, the bracket 29 is displaced up and down. However, since the displacement amount of the bracket 29 is small, the displacement sensor 92 detects the displacement amount of the displacement amount amplification arm 91 that amplifies the displacement amount of the bracket 29.

The biasing spring 93 is interposed between the arm 91 and the upper end of the slide member 94. Then, the slide member 94 is expanded and contracted to change the biasing force.

The slide member 94 is installed so as to be movable only in the vertical direction with respect to the main body of the image reading apparatus (not shown). The slide member 94 includes a moving rack 94.
A is formed.

A gear 97 is attached to the rotating shaft of the motor 95, and the gear 97 meshes with the rack 94A of the slide member 94.

Therefore, when the motor 95 is rotated clockwise in FIG. 6, the slide member 94 moves upward and the urging spring 93 contracts. When rotated in the counterclockwise direction, the slide member 94 moves downward to move the biasing spring 93.
Grows.

The home position sensor 96 detects whether or not the vertically movable slide member 94 is at a predetermined home position position (state of FIG. 6), and the slide member 94 is at the predetermined home position position. And a detection signal is output.

The limit sensor 98 detects whether or not the vertically movable slide member 94 is at a predetermined lowermost point position (a position lower than that in the state of FIG. 6), and determines the predetermined lowermost point position. When it is in, the detection signal is output.

The slide member 94 in the contact pressure changing mechanism 90 has a sheet material S at the nip portion of the pair of conveying rollers 22.
When is not entered, it is always placed at the home position position detected by the home position sensor 96.

As described above, in the biasing spring 93 when the slide member 94 is at the home position, the contact pressure between the driven roller 22B and the drive roller 22A becomes an intermediate value between the maximum contact pressure and the minimum contact pressure. It has a biasing force.

When a thick sheet material S enters the nip portion of the pair of conveying rollers 22, the slide member 94 at the home position is moved downward to increase the urging force of the urging spring 93. Driven roller 22B
The contact pressure between the drive roller 22A and the drive roller 22A is strengthened.

When a thin sheet material S enters the nip portion of the pair of conveying rollers 22, the slide member 94 at the home position is moved upward to lower the urging force of the urging spring 93. The contact pressure between the driven roller 22B and the drive roller 22A is weakened.

As described above, when the sheet material S has not entered the nip portion of the pair of transport rollers 22, the slide member 9
4 is placed at the home position and the slide member 94 is moved upward or downward from the home position, the driven roller 22B and the drive roller 2 are moved.
The contact pressure with 2A can be changed quickly.

After the power is turned on, if the sheet material S has not entered the nip portion of the conveying roller pair 22 and the slide member 94 is not at the home position position, the slide member 94 must be moved to the home position position. Here, the procedure for moving the slide member 94 to the home position will be described.

First, the motor 95 is rotated counterclockwise to move the slide member 94 downward. When the slide member 94 that has moved downward is detected by the home position sensor 96, the rotation of the motor 95 is stopped. At this point, the slide member 94 is set to the home position position.

When the slide member 94 is at a position lower than the home position, the slide member 94 is moved down to the position detected by the limit sensor 98. When the slide member 94 is detected by the limit sensor 98, the motor 95 is reversely rotated (clockwise) to move the slide member 94 upward. Then, when the slide member 94 is detected by the home position sensor 96, the rotation of the motor 95 is stopped. At this point, the slide member 94 is set to the home position position.

In the operation of setting the slide member 94 to the home position position, the motor 95 is controlled by the home position sensor 96 and the limit sensor 98.
Is performed based on the detection signal from the slide member 9
In the operation of moving 4 from the home position (contact pressure changing operation), the motor 95 is controlled based on the signal from the displacement sensor 92.

FIG. 7 shows the motor 9 of the contact pressure changing mechanism 90.
5 is a block diagram showing a configuration of a control circuit for controlling the control unit 5 of FIG.

The CPU 100 includes an input / output circuit (I / 0)
Through 101, the displacement sensor 92, the home position sensor 96, the limit sensor 98, the motor drive circuit 10
2. A pulse counter 103 is connected. A motor 95 is connected to the motor drive circuit 102, and a pulse generation circuit 104 is connected to the pulse counter 103.

Next, a method of controlling the motor 95 in the CPU 100 will be described.

The CPU 100 uses the sheet material conveying roller pair 2
If the sheet material S does not enter the nip portion of No. 2 (this state can be determined by the signal sent from the displacement sensor 92) and the detection signal from the home position sensor 96 is not input, the sheet material S is input via the input / output circuit 101. Motor drive circuit 1
A drive signal is output to 02 to rotate the motor 95 counterclockwise.

As a result, the slide member 94 not in the home position moves downward.

When the detection signal is input from the home position sensor 96, the CPU 100 outputs a stop signal to the motor drive circuit 102 via the input / output circuit 101 to stop the rotation of the motor 95.

As a result, the slide member 94 located above the home position is set to the home position.

Further, the CPU 100 uses the limit sensor 9
When the detection signal is input from 8, the motor 95 is rotated in the reverse direction.

As a result, the slide member 94 moves upward from the lowest point position.

When the detection signal is input from the home position sensor 96, the CPU 100 outputs a stop signal to the motor drive circuit 102 via the input / output circuit 101 to stop the rotation of the motor 95.

As a result, the slide member 94 located below the home position is set to the home position.

The above-described operation is premised on the fact that the sheet material S does not enter the nip portion of the sheet material conveying roller pair 22 after the power is turned on, and the detection signal from the home position sensor 96 is not input. If they are available, they are always done.

When the detection signal (the signal corresponding to the thickness of the sheet material S) from the displacement sensor 92 is input through the input / output circuit 101, the CPU 100 receives the input signal (current value).
Is compared with a predetermined value. Here, the predetermined value is the biasing force value of the biasing spring with respect to the input current value (thickness of the sheet material).

Then, the CPU 100 sends a drive signal to the motor drive circuit 102 via the input / output circuit 101 in order to move the slide member 94 so that the biasing force of the biasing spring 93 becomes a value corresponding to the input current value. Output, motor 95
Is rotated in a predetermined direction.

Here, the direction in which the slide member 94 at the home position is moved can be obtained based on the urging force value of the urging spring 93 at the home position.

That is, when the biasing force value corresponding to the input current value is smaller than the biasing force value at the home position, the slide member 94 is moved upward. in this case,
The motor 95 is rotated clockwise.

When the biasing force value corresponding to the input current value is larger than the biasing force value at the home position,
The slide member 94 is moved downward. In this case, the motor 95 rotates counterclockwise.

When the motor 95 rotates in a predetermined direction, the pulse generation circuit 104 generates a pulse corresponding to the rotation of the motor 95. Then, the pulse is measured by the pulse counter 103, and the CP is transmitted via the input / output circuit 101.
Input to U100.

When the pulse value sent from the pulse counter 103 reaches a predetermined value, the CPU 100 outputs a stop signal to the motor drive circuit 102 via the input / output circuit 101 to stop the motor 95. As a result, the contact pressure between the driven roller 22B and the drive roller 22A becomes a contact pressure according to the thickness of the sheet material S. Here, the predetermined value is a pulse value corresponding to the biasing force value of the biasing spring.

In the case of the contact pressure changing mechanism 90 of this embodiment, the thickness of the sheet material S that has entered the nip portion of the conveying roller pair 22 is detected, and the driven roller 22B of the conveying roller pair 22 and the driving roller 22A are detected. Since the contact pressure is changed to the contact pressure according to the thickness of the sheet material S, for example, even when the sheet materials S stacked on the sheet material mounting table 1 have different thicknesses, the present invention can be dealt with.

Further, when the sheet material S having a corrugation is conveyed by the conveying roller pair 22, the wrinkles generated in the sheet material S are gradually moved in the nip portion of the conveying roller pair 22 in the corrugated portion in the roller axial direction. As a result, the wrinkles do not occur at the tip of the sheet material S because they occur in the part where the escape area is lost.

Therefore, even if the contact pressure is changed after the sheet material S enters the nip portion of the conveying roller pair 22 as in the case of the contact pressure changing mechanism 90 of the present embodiment, the response speed is the sheet material conveyance. There is no problem if it is appropriate for speed,
Wrinkles can be prevented.

The first aspect of the invention is based on the above-mentioned first and second embodiments.
Not limited to the sheet material conveying device of the image reading device shown in
It can also be applied to a sheet material conveying device of an image forming apparatus such as a copying machine, a printer, and a facsimile. <Embodiment 1 of the second invention> FIG. 10 is a vertical cross-sectional side view showing a configuration of a sheet material feeding device according to Embodiment 1 of the second invention. 11 is a plan view showing the configuration of the sheet material feeding device, and FIG. 12 is a bottom view showing the configuration of the main part of the sheet material feeding device.

In the description of the present sheet material feeding device, the same members and the like as those of the above-mentioned conventional sheet material feeding device (FIG. 23) are designated by the same reference numerals and are structurally and functionally unchanged. The description of the items is omitted. The same applies to each sheet material feeding device of Embodiments 2 and 3 of the second invention described later.

In the present sheet material feeding device, when the sheet material placing table 201 is in the manual feeding posture at the end of the sheet material placing table 201 facing each feeding roller 212 (state of FIG. 10). Is located below the upper surface of the sheet material mounting table 201, and when the sheet material mounting table 201 is in the continuous feeding state (state of FIG. 18), a friction plate (sliding plate) that protrudes to the upper surface of the sheet material mounting table 201. Resistance means) 207.

The friction plate 207 is attached to the support member 206 attached to the lower surface side of the sheet material mounting table 201.

As shown in FIG. 13 (plan view) and FIG. 14 (side view), the support member 206 has a T-shape in plan view, and a pedestal portion 206A serving as an attachment portion of the friction plate 207.
And an arm portion 206B which is an attachment portion to the sheet material mounting table 201.
And the left and right rotation restricting portions 206C and 206C which are contact portions with the lower surface of the sheet material mounting table 201.

A friction plate 207 is attached to the upper surface of the pedestal portion 206A, and a thin plate-shaped arm portion 206B and rotation restricting portions 206C and 206C are integrally formed on the lower surface side of the pedestal portion 206A.

15 (bottom view) and FIG. 1 are provided at the end of the sheet material mounting table 201 facing the respective feeding rollers 212.
As shown in FIG. 6 (side view), a rectangular notch 201D is formed, and on the upper surface side of this notch 201D portion, left and right strip-shaped thin plate portions 201 that are contact portions of the feeding roller 212.
E and 201E are extended.

The supporting member 206 is the sheet material mounting table 201.
On the other hand, the pedestal portion 206A has a strip shape on the left and right sides of the thin plate portion 201A.
The arm portion 206B so that it is located between E and 201E.
The end portion of is fixed with a screw 206D.

When the sheet material mounting table 201 is in the manual sheet feeding mode shown in FIG. 10, the friction plate 20 on the pedestal portion 206A is used.
7 is at a position lower than the lower surfaces of the left and right strip-shaped thin plate portions 201E, 201E, and the left and right rotation restricting portions 206C,
206C is located away from the lower surface of the sheet material mounting table 201.

Therefore, when the sheet material placing table 201 is in the manual feed feeding mode, the friction plate 207 moves to the sheet material placing table 2
It is under the top of 01. As a result, the leading end of the sheet material that is manually fed can be smoothly inserted between the feeding roller 212 and the left and right strip-shaped thin plate portions 201E and 201E that are in contact with the feeding roller 212 at a predetermined pressure.

Further, when the sheet material placing table 201 is in the continuous paper feeding posture shown in FIGS. 17 and 18, when the pushing-up lever 204 is in a state of pushing up the sheet material placing table 201 (state of FIG. 18), the pushing-up lever is pushed. 204 presses the lower surface of the support member 206. As a result, the arm portion 206B bends until the left and right rotation restricting portions 206C and 206C come into contact with the lower surface of the sheet material mounting table 1, and the pedestal portion 206A.
The upper friction plate 207 projects to the upper surface of the sheet material mounting table 201.

Therefore, during continuous sheet feeding, the bottom sheet of the sheet material stacked on the sheet material mounting table 201 is the friction plate 2.
The state of contact with 07 prevents the bottom sheet from being fed integrally with the upper sheet material. <Embodiment 2 of the Second Invention> FIGS. 19 and 20 are longitudinal side views showing the configuration of a sheet material feeding device according to Embodiment 2 of the second invention.

In the present sheet material feeding device, when the sheet material placing table 201 is in the manual feeding posture at the end of the sheet material placing table 201 facing each feeding roller 212 (state of FIG. 19). When the sheet material placing table 201 is in the continuous sheet feeding state (the state shown in FIG. 20), the friction roller is pressed by the push-up lever 204 and cannot rotate. Sliding resistance means) 21
6 is provided.

The friction roller 216 is used for the sheet material mounting table 20.
It is rotatably attached to a support member 217 attached to the lower surface side of No. 1. The friction roller 216 has a structure in which a friction member 216A is wound around the outer peripheral portion.

The support member 217 is formed of a leaf spring and has an arm 217A. Then, the arm portion 217A is screwed to the sheet material mounting table 201.
It is fixed at B.

In this way, the support member 217 attached to the lower surface side of the sheet material mounting table 201 is restricted from moving upward by the roller shaft 216B that abuts the lower surface of the sheet material mounting table 201.

When the sheet material mounting table 201 is in the manual sheet feeding position shown in FIG. 19, the friction roller 216 rotatably supported by the supporting member 217 is moved toward the feeding roller 212 by the urging force of the arm portion 217A. It comes into contact with a predetermined pressure.

Therefore, when the feeding roller 212 rotates,
Since the friction roller 216 is rotated by the feeding roller 212, the leading end of the sheet material that is manually fed is set to the feeding roller 2
It can be smoothly inserted between 12 and the friction roller 216.

Further, when the sheet material mounting table 201 is in the continuous paper feeding position shown in FIG. 20, the push-up lever 204 for pushing up the sheet material mounting table 201 presses the friction roller 216.

Therefore, the friction roller 216 comes to project to the upper surface of the sheet material mounting table 201 in a non-rotatable state.

Therefore, the bottom sheet of the sheet material stacked on the sheet material mounting table 201 is prevented from coming into contact with the non-rotating friction roller 216 and the bottom sheet is fed integrally with the upper sheet material. To do.

Here, by setting the frictional force between the friction roller 216 and the push-up lever 204 to be larger than the frictional force between the friction roller 216 and the sheet material, the friction roller 216 formed by the sheet material. It prevents the accompanying rotation of. <Embodiment 3 of the second invention> FIG. 21 is a vertical sectional side view showing the configuration of a sheet material feeding device according to a third embodiment of the second invention, and FIG. 22 is a main part of the sheet material feeding device. It is a bottom view which shows a structure.

In the present sheet material feeding device, the sheet material mounting table 2 is provided on the lower surface side near the tip of the sheet material mounting table 201.
A charging device 218 for charging 01 and adsorbing the sheet material on the entire upper surface of the sheet mounting base 201 is provided.

The charger 218 is used for the sheet material mounting table 20.
When 1 is in the manual sheet feeding mode (state of FIG. 21), the sheet material mounting table 201 is turned off so as not to be charged. Then, when the sheet material mounting table 201 is in the state of continuous sheet feeding, it is turned on to charge the sheet material mounting table 201.

Further, a rectangular notch 201F is formed at the end of the sheet material mounting table 201 facing each feeding roller 212, and the notch 201F is provided on the upper surface side thereof.
The strip-shaped thin plate portion 2 serving as a contact portion at the center of the feeding roller 212
01G is extended.

Further, recesses 201H, 201H for fitting the left and right side portions of the feeding roller 212 are formed on the upper surfaces of the left and right side portions of the notch 201F.

When the sheet material placing table 201 is in the manual sheet feeding state shown in FIG. 21, the strip-shaped thin plate portion 201G of the sheet material placing table 201 comes into contact with the feeding roller 212 with its own spring force at a predetermined pressure. ing. Further, in the manual sheet feeding state, as described above, the sheet material mounting table 201 is not in the charged state.

Therefore, the leading edge of the sheet material manually fed can be smoothly inserted between the feeding roller 212 and the sheet material mounting table 201.

When the sheet material placing table 201 is in the continuous feeding state, the sheet material placing table 201 is pushed by the pushing force of the push-up lever 204 which pushes up the sheet material placing table 201.
The strip-shaped thin plate portion 201G is bent more than in the manual sheet feeding state, and the left and right side portions of the feeding roller 212 are left and right concave portions 201G.
H, 201H comes to enter. When in the continuous paper feeding state, as described above, the sheet material mounting table 201 is in the charged state.

Therefore, the sheet material mounting table 2 in which the bottom sheet of the sheet material stacked on the sheet material mounting table 201 is charged
01 is attached to the upper surface to prevent the lowermost sheet from being fed integrally with the upper sheet material.

Here, since the frictional force between the sheet material and the feeding roller 212 is set to be larger than the sheet material adsorbing force of the sheet material mounting table 201, the lowermost sheet should be completely fed. You can

Further, since the sheet material attracting force of the sheet material mounting table 201 is set to be larger than the frictional force between the sheet materials, the bottom sheet is fed integrally with the upper sheet material. There is no need to be done. <Embodiment 1 of the third invention> FIG. 26 is a vertical cross-sectional side view showing the overall configuration of an image reading apparatus including a sheet material conveying device according to Embodiment 1 of the third invention.

FIG. 27 is a perspective view showing the structure of the separation roller pair, the conveyance roller pair, and the registration roller pair of the image reading apparatus.

In the description of the present image reading apparatus, the same members as those of the conventional image reading apparatus (FIG. 34) are designated by the same reference numerals, and those which are structurally and functionally unchanged. Will not be described. The same applies to the image reading apparatus according to the second embodiment of the third invention described later.

In the present image reading apparatus, the conveying roller pair 407 is located at a cylindrical driven roller 407B having a constant width in the width direction of the sheet material S, and substantially in the center of the sheet material S in the width direction. In addition, it is constituted by a star-shaped drive roller 407C which makes partial contact with the driven roller 407B intermittently.

When the separation sheet material S is conveyed to the registration roller pair 408 by the conveyance roller pair 407, the registration roller pair 408 which is not rotating after the front end of the sheet material S is detected by the sheet material detection sensor 427. After the leading edge of the sheet material S reaches the nip portion of the registration roller pair 408, the star-shaped drive roller 4
It is set so that 07C rotates several times.

The conveying roller pair 407 intermittently conveys the sheet material S, abuts the leading end of the sheet material S against the nip portion of the registration roller pair 408 whose rotation is stopped, until the registration roller pair 408 rotates. In between, a star-shaped drive roller 4
07C rotates several times to form a loop on the sheet material S.

At this time, since the star-shaped drive roller 407C rotates in a state of intermittent partial contact with the driven roller 407B, the contact state and the non-contact state of the driven roller 407B are alternately repeated. There is. Therefore,
When the star-shaped drive roller 407C is not in contact with the driven roller 407B, the loop thus formed disappears due to the restoring force of the waist of the sheet material S, and the operation of forming a loop again in the contact state is repeated. become.

Therefore, even if a loop is formed in a state where the leading edge of the sheet material S does not enter the nip portion of the registration roller pair 408, the leading edge of the sheet material S is aligned with the nip portion of the registration roller pair 408 in the above-described repetition. Then, the skewed state is corrected.

Further, since the star-shaped drive roller 407C is in contact with the driven roller 407B via the projection 407C-1 at the substantially central portion in the width direction of the sheet material S, the sheet material S is skewed. Then, when the left and right loop amounts are different, when the projection 407C-1 of the star-shaped drive roller 407C contacts the driven roller 407B, the projection 4 of the star-shaped drive roller 407C
Since the leading side having a large loop amount rotates in the backward direction around 07C-1, the skewed state can be corrected more effectively.

[0205] In the thin and weak sheet material S whose tip portion is easily caught by the registration roller surface, the skewed state can be effectively corrected, and wrinkles do not occur at the tip of the sheet material when it is caught in the registration roller. .

Here, the star-shaped drive roller 407C is used.
If the peripheral speed is set to be higher than the sheet material conveying speed, the conveyance of the sheet material S is accelerated, and the leading edge of the sheet material easily enters the nip portion of the registration roller pair 408.

28, 29, and 30, the sheet material S separated by the separation roller pair 406 is conveyed by the conveyance roller pair 407 to the registration roller pair 408 whose rotation is stopped, and the registration roller pair 408 obliquely moves. The flow until the state is corrected and the state of the star-shaped drive roller 407C are shown.

When the leading edge of the sheet material S transported by the transport roller pair 407 reaches the immediately upstream portion of the registration roller pair 408, it is detected by the sheet material detection sensor 427 (FIG. 28).

After a lapse of a predetermined time from this point, the registration roller pair 408 whose rotation is stopped rotates.

The sheet material S detected by the sheet material detection sensor 427 further advances, and the leading edge of the sheet material reaches the nip portion of the registration roller pair 408 (FIG. 29).

From this point, star-shaped drive roller 407C
By rotating the sheet several times, a predetermined loop for correcting the skewed state of the sheet material S is formed.

The loop formed on the sheet material S disappears due to its own restoring force when the star-shaped drive roller 407 comes into non-contact with the driven roller 407B. When the star-shaped drive roller 407C comes into contact with the driven roller 407B again, a loop is formed. By repeating this several times, the skewed state of the sheet material S is corrected. Figure 30
Indicates this state.

If the distance (pass length) L between the separation roller pair 406 and the registration roller pair 408 is set to be equal to or longer than the longest usable sheet material S, the sheet material S
When correcting the skewed state, the rear end of the sheet material S passes through the nip portion of the separation roller pair 406, so that the degree of freedom of the sheet is increased and the leading end of the sheet material S is easily aligned with the nip portion of the registration roller pair 408. As a result, the skewed state can be surely corrected.

However, the shortest sheet material S that can be used here is the distance L1 between the separation roller pair 406 and the conveyance roller pair 407, the conveyance roller pair 407 and the registration roller pair 4.
It is restricted to a longer one than the distance L2 between 08. <Embodiment 2 of Third Invention> FIG. 31 is a vertical cross-sectional side view showing an overall configuration of an image reading apparatus including a sheet material conveying device according to Embodiment 2 of the third invention.

In the present image reading apparatus, when the sheet material detection sensor 427 detects the leading edge of the sheet material S being conveyed by the conveying roller pair 407, at that time, the feed roller 406A and the retard roller 406 of the separation roller pair 406 are retarded. The contact state of the roller 406B is released.

In this way, the registration roller pair 49
8, when correcting the skewed state of the sheet material S, the skewed state can be reliably corrected by utilizing the rotation of the sheet material S due to the action of the loop. Then, in the case of this configuration, as in the case of the configuration in which the distance L between the separation roller pair 406 and the registration roller pair 408 is made larger than the length of the longest sheet material S to be used (FIG. 26), usable sheets can be used. The material size is not restricted.

In this image reading apparatus, the feed roller 406A is fixed in position with respect to the image reading apparatus main body (not shown), and the retard roller 406B is fixed in position.
Feed roller 406A for the main body of the image reading device
It is attached so that it can move toward and away from.

The retard roller 406B is the solenoid 4
When 28 is in the ON state, the feed roller 406A
Is in contact with a predetermined pressure. And solenoid 4
When 28 is turned off, it is separated from the feed roller 406A. At this time, the retard roller 406B is pushed down by the lever 429 that rotates counterclockwise about the support shaft 429A by the biasing force of the coil spring 430.

Therefore, when the sheet material detection sensor 427 detects the leading edge of the sheet material, the solenoid 428 is turned off and the rollers 406A, 40 of the separation roller pair 406 are separated.
Release the contact state of 6B.

In this embodiment, when the sheet material detection sensor 427 detects the leading edge of the sheet material, the separation roller pair 40
The contact state of the rollers 406A and 406B of No. 6 is released. At this time, if the rear end of the sheet material S has not passed the feeding roller 405, the sheet material mounting table 401 is lowered to remove the sheet material S from the sheet material S. The feeding roller 405 is separated.

In each of the first and second embodiments described above, the case where a star-shaped roller located at the center of the sheet material S in the width direction is used as the driving roller 407 of the conveying roller pair 407 has been described. The drive roller 407C of the pair 407 may be a gear type roller shown in FIG. 32, an impeller type roller shown in FIG. 33, or the like. In short, the driven roller 40
If the roller has a structure that intermittently contacts 7B,
Regardless of the length of the roller, it can perform the same function as a star-shaped roller when correcting a skewed state.

The third aspect of the invention is based on the above-mentioned first and second embodiments.
Not limited to the sheet material conveying device of the image reading device shown in
It can also be applied to a sheet material conveying device of an image forming apparatus such as a copying machine, a printer, and a facsimile.

[0223]

As described above, in the sheet material conveying device of the first invention, the contact pressure of each roller of the conveying roller pair arranged immediately downstream of the separation roller pair is set to the thickness of the sheet material. I changed it accordingly.

Therefore, the conveying roller pair conveys the sheet material separated by the separating roller pair with a contact pressure corresponding to the thickness thereof.

Therefore, even when the conveying roller pair conveys a thin and weak sheet material from the separating roller pair, the corrugated portion of the sheet material is in the roller axis direction in the nip portion of the conveying roller pair. Since there is pressure to escape,
Wrinkles do not occur in the pair of conveying rollers.

Further, in the sheet material feeding device of the second invention, the bottom sheet of the sheet material stacked on the sheet material mounting table is not fed integrally with the upper sheet material during continuous sheet feeding. The sliding resistance means that provides the sliding resistance between the bottom sheet on the sheet material placing table and the sheet material placing table does not give resistance to the manually fed sheet material during manual feeding. I chose

Therefore, the leading edge of the manually inserted sheet material is smoothly inserted between the feeding roller and the sheet material mounting table and reliably fed by the feeding roller.

Further, in the sheet material conveying device of the third invention, the driving roller of the conveying roller pair for conveying the sheet material to the registration roller pair is a roller which is in contact with the driven roller intermittently.

Thus, the abutting operation against the pair of registration rollers can be repeated.

Therefore, even when a loop for correcting the skewed state is formed in a state where the leading edge of the sheet material does not enter the nip portion of the registration roller pair, the above-mentioned protrusion of the registration roller pair onto the nip portion is formed. By repeating the applying operation, the skewed state of the sheet material is surely corrected.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an overall configuration of an image reading apparatus including a sheet material conveying device according to a first embodiment of the first invention.

FIG. 2 is a vertical sectional side view showing a detailed configuration of a main part (invention part) of the image reading apparatus.

FIG. 3 is a plan view showing a detailed configuration of a main part (invention part) of the image reading apparatus.

FIG. 4 is a front view showing an overlapping state of a feed roller large diameter portion and a retard roller large diameter portion of a separation roller pair in the image reading apparatus.

FIG. 5 is a front view showing a corrugated region generated in the pair of separation rollers.

FIG. 6 is a vertical cross-sectional side view showing the configuration of the sheet material conveying device according to the second embodiment of the first invention.

FIG. 7 is a block diagram showing a configuration of a motor control circuit of a contact pressure changing mechanism provided in the sheet material conveying device.

FIG. 8 is a vertical cross-sectional side view showing a configuration of a separation roller pair of a conventional example and a conveyance roller pair that conveys a sheet material separated by the separation roller pair downstream.

FIG. 9 is a front view showing a corrugated state of a sheet material generated in the pair of separation rollers.

FIG. 10 is a vertical cross-sectional side view showing a configuration of a sheet material feeding device according to a first embodiment of the second invention and a state of a friction plate when the sheet material mounting table is in a manual sheet feeding posture.

FIG. 11 is a plan view showing the configuration of the sheet material feeding device.

FIG. 12 is a bottom view showing the configuration of the main part of the sheet material feeding device.

FIG. 13 is a plan view showing a configuration of a support member that supports a friction plate provided in the sheet material feeding device.

FIG. 14 is a side view showing the configuration of the support member.

FIG. 15 is a bottom view showing the configuration of a friction plate supporting member installation portion of the sheet material mounting table provided in the sheet material feeding device.

FIG. 16 is a side view showing a configuration of a friction plate support member installation portion of the sheet material mounting table.

FIG. 17 is a vertical cross-sectional side view showing a state of the friction plate when the sheet material mounting table of the sheet material feeding device is before the continuous sheet feeding operation.

FIG. 18 is a vertical cross-sectional side view showing a state of the friction plate when the sheet material mounting table is in a continuous paper feeding operation.

FIG. 19 is a vertical cross-sectional side view showing a configuration of a sheet material feeding device according to a second embodiment of the second invention and a state of a friction roller when the sheet material mounting table is in a manual feeding state.

FIG. 20 is a vertical cross-sectional side view showing a state of the friction roller when the sheet material mounting table is in a state of continuous sheet feeding.

FIG. 21 is a vertical cross-sectional side view showing a configuration of a sheet material feeding device according to a third embodiment of the second invention and a state in which the sheet material placing table is in a manual feeding posture.

FIG. 22 is a bottom view showing the configuration of the main part of the sheet material feeding device.

FIG. 23 is a vertical cross-sectional side view showing a configuration of a sheet material feeding device of a conventional example and a state of a friction member when the sheet material placing table is in a manual feeding state.

FIG. 24 is a vertical cross-sectional side view showing a state in which the leading edge of the sheet material abuts on the feeding roller and is curved when the sheet material feeding device is manually fed.

FIG. 25 is a vertical cross-sectional side view showing a state in which the leading edge of the sheet material is buckled by the detection lever during manual feeding of the sheet material feeding device.

FIG. 26 is a vertical cross-sectional side view showing the overall configuration of the image reading apparatus including the sheet material conveying device according to the first embodiment of the third invention.

FIG. 27 is a perspective view showing configurations of a separation roller pair, a conveyance roller pair, and a registration roller pair of the image reading apparatus.

FIG. 28 is a vertical cross-sectional side view showing a state where the sheet material is being conveyed to the registration roller pair by the conveyance roller pair.

FIG. 29 is a vertical cross-sectional side view showing a state where the leading edge of the sheet material conveyed by the pair of conveying rollers abuts against the nip portion of the pair of registration rollers.

FIG. 30 is a vertical cross-sectional side view showing a state in which the skewed state of the sheet material conveyed by the conveying roller pair is corrected by the registration roller pair.

FIG. 31 is a vertical cross-sectional side view showing the overall configuration of an image reading apparatus including a sheet material conveying device according to a second embodiment of the third invention.

FIG. 32 is a perspective view showing another example of the structure of the driving roller of the pair of conveying rollers which constitutes the third invention.

FIG. 33 is a perspective view showing still another example of the structure of the driving roller of the pair of conveying rollers which constitutes the third invention.

FIG. 34 is a vertical cross-sectional side view showing the overall configuration of a conventional image reading apparatus.

[Explanation of symbols]

 10 Separation roller pair 21, 90 Contact pressure changing mechanism (contact pressure changing means) 22, 407 Conveying roller pair 22A, 407C Driving roller 22B, 407B Followed roller 201 Sheet material mounting table 207 Friction plate (sliding resistance means) 212 Feeding Roller 216 Friction roller (sliding resistance means) 218 Charging device (sliding resistance means) 408 Registration roller pair S Sheet material

Claims (7)

[Claims] 1. A sheet material conveying device for conveying a sheet material, which has been separated one by one by a pair of separating rollers, to a predetermined downstream position by using an appropriate number of pairs of conveying rollers. A sheet material conveying device comprising contact pressure changing means for changing the contact pressure of each roller of the pair of conveying rollers that is formed according to the thickness of the sheet material. 2. The contact pressure changing means changes the contact pressure of each roller of the conveying roller pair in conjunction with the operation of changing the overlap amount of each roller of the separation roller pair. Item 1. The sheet material conveying device according to item 1. 3. The contact pressure changing means changes each roller contact pressure of the conveying roller pair based on the thickness information from the sheet material thickness detecting means for detecting the thickness of the sheet material. The sheet material conveying device according to claim 1. 4. Connected paper feeding using a common feeding roller,
In a sheet material feeding device provided with a sheet material placing table capable of manual sheet feeding, when the sheet material placing table is in a state of continuous feeding, a predetermined distance is provided between the sheet material placing table and the sheet material. Sliding resistance means for applying a sliding resistance force and for not applying a sliding resistance force between the sheet material mounting base and the sheet material when the sheet material mounting base is in a manual feeding state A sheet material feeding device comprising: 5. A sheet material conveying device comprising: a registration roller pair that corrects a skewed state of a sheet material; and a conveyance roller pair that conveys the sheet material to the registration roller pair. A sheet material conveying device comprising: a cylindrical driven roller having a constant width in the width direction of the sheet material; and a driving roller having a shape which makes partial contact with the driven roller intermittently. 6. The sheet material conveying device according to claim 5, wherein the pair of driving rollers of the conveying rollers are rotationally driven at a peripheral speed higher than the sheet material conveying speed. 7. The sheet material conveying device according to claim 5, wherein after the leading edge of the sheet material reaches the nip portion of the pair of registration rollers, a conveying force is applied to the sheet material only by the pair of conveying rollers. .