CN1530306A - Paper feeder in image reading device - Google Patents

Abstract

A paper feeder includes a plurality of roller pairs arranged in pairs on the downstream side of a reading point, and the roller pairs are a driving roller section and a driven roller section pressing on the driving roller section. The outer layer of at least each drive roller section is made of a material having a relatively high coefficient of friction with the document paper, such as rubber, and the outer layer of at least each driven roller section is made of a material with a low coefficient of friction relative to the document paper become. The driving roller section is arranged on an axis perpendicular to the paper feeding direction, and the driven roller section is arranged symmetrically with respect to the centerline of the width of the document paper on an axis inclined to the paper feeding direction. In addition, the axes of the driven roller segments are inclined so that the end of the axis of each roller segment farthest from the center line is located on the upstream or downstream side of the sheet feeding direction, and the end closest to the center line is located on the opposite side from the other. The downstream side or upstream side in the direction of paper feed where one end is opposite.

Description

Paper feeder in image reading device

technical field

The present invention relates to a paper feeder capable of feeding paper such as documents in an image reading apparatus, and particularly to a structure capable of preventing the Image reading failure caused by the momentary stop of the fed paper in the reading section.

Background technique

Usually, in facsimile machines, scanners, and copiers, multiple documents are stacked at one place, and these documents are fed one by one by an automatic document feeder, so that the documents can be read without a linear CCD camera or a linear contact image sensor (CIS). The reading part is able to read the images on the file. In this case, a sheet feeder including a pair of rollers (with one driving roller and one driven roller used as a pair) is provided on the downstream side of the reading section. If the axes of the driving roller and the driven roller are arranged in a direction perpendicular to the paper feeding direction, the nip portion between the driving roller and the driven roller extends in the axial direction of the rollers and is parallel to the direction perpendicular to the paper feeding direction. Therefore, at the moment when the leading edge of the paper collides with the gripping portion along the length of the gripping portion and the width of the paper, the load at the collision point is large, and the feeding of the paper is momentarily stopped, causing damage to the paper at the reading portion. The movement of the image is read, and the image data cannot be obtained accurately.

On the other hand, when the paper passing through the paper discharge mechanism does not have rigidity (insufficient rigidity), as a structure for enhancing rigidity, Japanese Laid-Open Patent Document No. 2001-310857 ( FIGS. 1 to 5 ) discloses a A paper discharge mechanism that discharges paper from the inside of the device. This mechanism consists of a pair of rollers, which are a driving roller and a driven roller that presses against the driving roller. The axis of the driven roller that presses the paper to the driving roller that conveys the paper in the paper discharge direction is located on a plane parallel to the axis of the driving roller, and is arranged symmetrically with respect to the center line of the paper being discharged and inclined with respect to the axis of the driving roller .

According to this structure, the discharged paper is bent at the center of the width, and this bending is continuously generated in the conveying direction, which generates shape-based rigidity in the paper, thereby giving the paper rigidity. Therefore, it is possible to prevent the paper from hanging down downstream of the roller feed, and it is possible to prevent paper jamming at the time of discharge.

However, if the paper feeder consisting of paired rollers having the structure disclosed in the foregoing publication is arranged on the downstream side of the reading section, the bending protruding substantially at the center of the document may continue to occur until reaching the upstream side of the feeding. side. Thus, the curvature may be a curvature approaching or away from the reading portion, so that the distance from the document to the reading portion may vary between portions with and without curvature. Consequently, the extent to which the document approaches the reading portion along its width varies greatly. Thus, image data of the correct size cannot be obtained.

Contents of the invention

The present invention provides a sheet feeder in an image reading apparatus capable of correctly obtaining an image.

According to the present invention, a sheet feeder for feeding sheets in an image reading apparatus having an image reading section includes: a driving roller assembly disposed on a downstream side of the reading section in a sheet feeding direction and including a driving roller; and A driven roller assembly includes a driven roller pressed against the drive roller. The friction coefficient between the outer layer of the driven roller and the supplied paper is smaller than that between the outer layer of the driving roller and the paper, the axis of the driving roller is perpendicular to the paper feeding direction, and the axis of the driven roller is inclined relative to the paper feeding direction. The nip portion between the driven roller and the driving roller becomes a point with respect to the leading edge of the paper perpendicular to the paper feeding direction. After the paper is clamped, the paper is conveyed in the direction of discharging the paper by the drive roller with a higher coefficient of friction, and slippage occurs between the driven roller with a lower coefficient of friction and the paper. Therefore, since the entry resistance of the leading edge of the paper at the nip portion is reduced, the impact is less. Therefore, a small impact does not cause the phenomenon of temporarily stopping the advance of the paper or bending the paper at the reading portion. Therefore, problems such as distortion of image read data at the read portion do not arise, so that the read operation can be stably maintained.

According to the present invention, the driven roller assembly includes a plurality of driven rollers, the driven rollers are arranged symmetrically on both sides of the center of the fed paper width, and the axes of the driven rollers are arranged obliquely in the center of the fed paper width on both sides. The nip portion formed between the driven roller and the driving roller is also symmetrically arranged with respect to the center of the width of the paper, so that the paper is not deviated in the width direction of the paper. Since the paper is conveyed stably, problems such as distortion of image read data at the reading portion do not occur, so that the reading operation can be stably maintained.

According to the present invention, the axes of the driven rollers are set in such a way that the end of each axis away from the center of the fed paper width is located on the upstream side of the paper feeding direction, while the end of each axis near the center of the fed paper width The end of the is located on the downstream side in the paper feeding direction. With this structure, the paper is clamped at portions close to both sides of the paper with respect to the width, so that image reading can be realized more stably.

According to the present invention, in the driven roller assembly, a plurality of driven rollers are provided on each side of the center of the fed paper width. With this structure, the paper can be held in the holding portion regardless of the size of the paper.

According to the present invention, the axes of the driven rollers disposed on each side of the center of the fed paper width are aligned on each side of the center of the fed paper width. Also in this case, regardless of the size of the paper, the paper can be held at the holding portion, and the driven roller is supported by one shaft, so that the structure can be simplified.

According to the present invention, the axes of the plurality of driven rollers are not arranged in a straight line so that one end of each driven roller axis on the side away from the paper width center is arranged on the upstream side in the paper feeding direction, and one end near the paper width center is arranged. One end of each driven roller axis on the side is disposed on the downstream side in the sheet feeding direction. In this case, wider paper is processed at the nip portion between the driven roller and the drive roller provided on the side away from the paper width center, and the driven roller and the drive roller on the side closer to the paper width center Narrow paper can be handled at the nip between the drive rollers. In addition, the amount of movement in the direction in which each driven roller comes into contact with the driving roller can be reduced. Therefore, the paper passing between the rollers can be properly discharged in a predetermined direction.

According to the present invention, the driven roller assembly includes a loading member that urges the driven roller toward the driving roller, and the loading member can independently load the driven roller at least on both sides of the center of the width of the paper being fed. Therefore, the force of the clamping portion on both sides can be kept constant.

According to the present invention, the paper feeder further includes: a conveying roller pair disposed upstream of the reading point in the paper feeding direction, wherein a paper conveying path from the conveying roller pair to the pair of driving and driven rollers is curved. Since the leading edge of the paper collides with the nip portion, the paper is susceptible to impact (resistance). However, when the paper is conveyed on the curved paper conveying path, it is possible to reduce the possibility of occurrence of undesired conditions such as temporary stop or bending of the paper at the reading portion, so that the beneficial effects of the present invention are more remarkable.

Description of drawings

Embodiments of the present invention are described in detail with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a multifunctional device including a document reader having an automatic document feeder according to an embodiment of the present invention;

Fig. 2 is a perspective view showing the cover of the document reader with the automatic document feeder opened from the main body casing;

Fig. 3 is a side sectional view showing the main part of the document reader with the automatic document feeder;

4 is a top view of a pair of discharge rollers disposed on the downstream side of the document reading portion with respect to the sheet feeding direction;

Figure 5A is a top view of driven rollers other than driving rollers;

FIG. 5B is an enlarged perspective view showing guide grooves for supporting shafts supporting driven rollers;

Figure 5C is an enlarged cross-sectional view along the line Vc-Vc shown in Figure 5A;

FIG. 6A is a view showing a first embodiment of the present invention;

FIG. 6B is a view showing another embodiment of the present invention;

Fig. 6C is a view showing another embodiment of the present invention.

Detailed ways

An illustrative embodiment of the invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, this embodiment is applicable to a document reader 2 having an automatic document feeder 6 in a multifunctional device 1 having a fax function, a scanning function, a copying function and a printing function.

On the top surface of the main body casing 3 of the multifunctional device 1, a large-sized glass plate 4 for placing documents is fixed in a horizontal state. At the front of the top surface of the main body casing 3, an operation panel portion 5 is provided. The operation panel 5 includes a ten-digit keypad for performing a facsimile function, a scan function, and a copy function, buttons for sending various operation instructions, and a liquid crystal display.

As shown in FIGS. 1 and 2 , the document reading machine 2 with the automatic document feeder 6 is composed of a cover assembly 7 , the automatic document feeder 6 and a reading element 9 . The cover assembly 7 is fixed to the rear edge of the top surface of the main body casing 3 via a hinge 8 so as to be able to turn up and down. The automatic sheet feeder 6 is provided on one end of the top surface of the cover assembly 7 . The reading element includes a linear CCD camera device, which is provided on one end of the lower surface of the glass plate 4a on one side of the glass plate 4. The glass plate 4 is fixed to the upper surface of the main body casing 3 . In this embodiment, the structure adopted by the document reading machine 2 is: a document placed on the large-sized glass plate 4 is fixed face down by a fixing element 7a. The fixing element 7 a is, for example, a sponge pad provided on the lower surface of the cover assembly 7 . According to the image reading instruction, the image on the document is read by the reading element 9 moving on the guide rail 10 provided along the lower surface of the large-sized glass plate 4 .

1 to 3, the structure of the automatic document feeder 6 in the document reading machine 2 will be described. As shown in FIG. 1, a housing portion 11 of the automatic document feeder 6 is fixed on one end of the cover assembly 7, and a file tray 12 is disposed at one end of the housing portion 11 at an oblique angle so that its free end extends upward. Below the document tray 12, a paper discharge tray 13 is formed on the top surface of the cover assembly 7 from which documents P are discharged.

As shown in FIG. 3 , in the case portion 11 , a start portion 14 a of the upper path plate 14 is disposed in abutment against the file tray 12 . On the upper side path plate 14 are provided a separation roller 15 (for feeding documents P while separating documents stacked in multiple layers on the document tray 12 one by one), a paper sensor 16 (which has a The detection lever 16a) which is rotated by contact with it, and a pair of paper feed rollers 17a, 17b. The downwardly bent end portion 14b of the upper path plate 14 and the starting portion 18a of the lower path plate 18 partially overlap. An end portion 18 b of the lower path plate 18 extends toward discharge rollers 19 , 20 provided in a proximal end portion of the paper discharge tray 13 . A pair of conveying rollers 21a, 21b is provided near the start portion 18a of the lower path plate 18 on the upstream side of the reading point 23a. Next to the conveyor rollers 21a, 21b, there is provided a rear sensor 22 with a detection lever 22a. The detection lever 22a detects the front and rear edges of the document P to find out its length and determine a paper jam. The lower path plate 18 is bent downward at a central portion with respect to the feeding direction, and includes a reading window 23 at its lowest position. The reading window 23 is rectangular in plan view and opens above the reading device 9 in the rest position. The reading window 23 is formed such that the length Lo in the paper feeding direction is short and the length in the direction perpendicular to the paper feeding direction is long (see FIGS. 1 and 3 ). A plurality of ribs 24 are provided above the lower path plate 18 so that the lower surface of the document P from which the image is read can slide on the surface of the reading point 23a with a narrow gap through which the document P can pass. On one edge of the side glass plate 4a is fixed a guide 25 capable of guiding the document P passing the reading point 23a toward the downstream side in the feed direction on the upper surface of the lower path plate 18 .

The end of cover 26 on one end of housing portion 11 (opposite file tray 12) is rotatable about axis 27 and is structured to expose the upper portion of upper path plate 14 in the event of a paper jam.

Below, with reference to accompanying drawing 3,4 and 5, illustrate the structure of a pair of discharge roller, this pair of discharge roller is a drive roller 19 and a driven roller 20, and these two rollers can play a role in the discharge side of supply direction. The role of paper utensils. The driving roller 19 and the driven roller 20 are disposed on the downstream side of the reading point 23a. Both the driving roller 19 and the driven roller comprise a plurality of roller segments. The drive roller 19 provided on the upper side is fixed to a drive shaft 29 parallel to the direction perpendicular to the paper feed direction (X-axis direction in FIG. 4 ), and the drive shaft 29 is along the paper feed direction, by A drive motor and a drive gear are shown turning. At least the outer peripheral layer of the driving roller 19 is made of rubber, which has a very large coefficient of friction compared to Document P. With respect to the width of the document (the paper size in the Y-axis direction in FIG. 4), on each side of the center line O of the document P, symmetrically at a plurality of positions on the drive shaft 29 and the support shaft 30 (in In this embodiment, the roller segments of the paired drive roller 19 and the driven roller 20 are provided at four locations or in pairs.

On the other hand, at least the outer peripheral layer of the roller segment of each driven roller 20 is made of a synthetic material such as polyacetal, which has a lower friction with respect to the document P than the driving roller 19 coefficient.

In order to use only the driving roller 19 to control the feeding direction of the paper to prevent paper deviation, the driven roller 20 preferably has a minimum coefficient of friction, that is, the friction coefficient of the driven roller 20 must be at least lower than that of the driving roller 19 .

The roller segments of the driven roller 20 are mounted on a pair of support shafts 30 so as to be pressed against the corresponding roller segments of the driving roller 19, respectively. In the embodiment shown in Figures 4 and 5, two roller sections of the driven roller 20 are arranged symmetrically on each side of the center line O, and the axis 20a of the roller section of the driven roller 20 (the axis of the support shaft 30) Not perpendicular to the paper feeding direction (X-axis direction), that is, not parallel to the Y-axis direction, but inclined by an angle θ (for example, 1-3 degrees in this embodiment) relative to the Y-axis. The roller segments of the driven roller 20 are arranged obliquely so that the roller segments of the driven roller 20 closer to the center line O are located on the downstream side in the sheet feeding direction, and the roller segments of the driven roller 20 farther from the center line O are located on the upstream side (see FIG. 5A ) . The support shaft 30 is supported in a guide groove 31 which opens upward in the housing part 11 so that the support shaft 30 can move vertically (FIG. 5B). The supporting shaft 30 is loaded by a loading member 33 (such as a coil spring, a leaf spring, and an elastic member made of rubber), wherein the loading member is installed in a recessed receiving portion formed adjacent to each guide groove 31. In section 32, therefore, a segment of driven roller 20 is pressed against a segment of drive roller 19 (FIG. 5C).

The guide grooves 31 supporting the respective support shafts 30 are formed in pairs at misaligned positions so that the inside guide grooves 31 (provided on the side near the center line O) are located on the downstream side in the sheet feeding direction with respect to the drive shaft 29 , while the outer guide groove 31 (provided at a position away from the center line O) is located on the upstream side in the sheet feeding direction with respect to the drive shaft 29, so that the support shaft 30 is inclined at an angle θ.

According to the above structure, as shown in FIGS. 4 and 6A, the leading edge P1 of the document P conveyed from the upstream side of the sheet feeding direction first collides with the nip portions N1, N1 between the roller segments of the driving roller 19 and the roller segments of the driven roller 20. . The nip portions N1, N1 are located closest to the upstream side in the sheet feeding direction (FIG. 6A) of the obliquely disposed roller segments of the driven roller 20, and substantially contact the leading edge P1 of the document P at multiple points so that the impact is small. Therefore, when the document P is fed by the transport rollers 21a, 21b and passes the reading point 23a, and the leading edge P1 of the document P collides with the nip portions N1, N1, the impact (entry resistance of the leading edge P1) can be greatly reduced. A small impact does not cause the phenomenon that the advancement of the document P is temporarily stopped or the document P is bent at the reading point 23a. Therefore, there is no problem of distortion of the image read data at the read point 23a, so that the read operation can be stably maintained.

In the embodiment shown in FIG. 6B, the roller segments of the driven roller 20 are arranged symmetrically on both sides of the center line O, and the axis 20a is arranged obliquely so that the roller segments of the driven roller 20 close to the center line O are located upstream in the paper feeding direction. side, and the roller section of the driven roller 20 away from the center line O is located on the downstream side in the paper feeding direction.

In the embodiment shown in FIG. 6C , the roller segments of the driven roller 20 near each side of the center line O are arranged obliquely in such a manner as to be located on the upstream side in the sheet feeding direction. The axis 20a of the roller segment of the driven roller 20 away from the central line O is perpendicular to the paper feeding direction (X-axis direction), that is, arranged parallel to the Y-axis direction.

The embodiment shown in Figures 6B and 6C has the advantage of being able to securely secure the leading edge P1 of the document P at the pair of gripping portions N1 and still form a point contact even when the width W1 of the document P is small form, as in the embodiment shown in Figure 6A.

As another example, the driving roller 19 can be combined into one or two roller sections extending in a continuous length along the Y-axis direction, and a plurality of driven roller 20 roller sections can be arranged to press the one or two roller sections at a certain interval. roll section. As an alternative, a loading member 33 may be provided for each roller segment of the driven roller 20 so as to independently drive the driven roller segments.

In addition, on the roller segment of the driven roller 20, the axis 20a of only one roller segment of the driven roller 20 can be inclined toward the upstream side or the downstream side of the paper feeding direction in the same principle as the embodiment.

Since the loading member 33, which loads the roller section of the driven roller 20 so as to be in contact with the drive roller 19, is provided on each axis 20a arranged symmetrically with respect to the document width center, the number of installation positions of the loading member 33 can be reduced, Thereby, the cost can be reduced.

If the nip portion N1 between the delivery rollers 21a, 21b on the upstream side of the reading point 23a to the nip portion N1 between the discharge rollers 19, 20 on the downstream side of the reading point 23a is formed curvedly in the direction from the top to the bottom As for the paper feeding path, the document P loses its own rigidity compared to when the paper feeding path is linear. Therefore, when the leading edge P1 of the document P hits the nip portion N1 between the discharge rollers 19, 20, the document P may stop for a moment or bend at the reading point 23a due to the impact (resistance). However, with the above structure, it is possible to avoid problems such as bending. Additionally, in FIG. 3, the orientation of the paper (document P) may be changed in the path from the reading point 23a to just before the nip between the discharge rollers 19, 20 so that the paper is substantially parallel to the glass plate 4, The leading edge P1 can then be inserted into the clamping portion. With this structure, the impact at the gripping portion can be reduced, and thus the conveyed document P can be prevented from bending at the reading point 23a.

The present invention can be applied not only to an automatic sheet feeder but also to a paper discharge portion located on the downstream side of a device capable of feeding sheets (documents P) one by one and reading while being conveyed.

Claims (20)

1. feeder, it is used for supplying with paper at the arrangement for reading image with reading image part, and it comprises:

A driven roller assembly, it is read downstream partly and comprises a driven roller to being arranged on along paper feeding; And

A driven voller assembly, it comprises a driven voller that is pressed on the driven roller;

Wherein, driven voller skin and the friction coefficient of the friction coefficient that is supplied to paper less than driven roller skin and paper; And

The axis normal of driven roller in paper feeding to setting, and the axis of driven voller with respect to paper feeding to being obliquely installed.

2. feeder according to claim 1, wherein: the driven voller assembly comprises a plurality of driven voller roller sections, these driven voller roller sections are arranged on the both sides at the width center that is supplied to paper symmetrically, and the axis of driven voller roller section is obliquely installed the both sides at the width center that is supplied to paper symmetrically.

3. feeder according to claim 2, wherein: the set-up mode of the axis of driven voller roller section is, away from the end of each axis at the width center that is supplied to paper all be positioned at paper feeding to upstream side, and near the end of each axis at the width center that is supplied to paper be positioned at paper feeding to the downstream.

4. feeder according to claim 2, wherein: in the driven voller assembly, a plurality of driven voller roller sections are set all on each side at the width center that is supplied to paper.

5. feeder according to claim 4, wherein: the axis that is arranged on the driven voller roller section on each side at the width center that is supplied to paper on each side at the width center that is supplied to paper in line.

6. feeder according to claim 4, wherein: the setting that do not form straight line of a plurality of driven voller roller sections, so that be arranged on away from the driven voller on the side at paper width center paper feeding to upstream side, and near the driven voller on the side at paper width center be arranged on paper feeding to the downstream.

7. feeder according to claim 2, wherein: the driven voller assembly comprises a loaded member towards driven roller promotion driven voller roller section, and described loaded member can independently load driven voller roller section in the both sides at the width center that is supplied to paper at least.

8. feeder according to claim 1, it also comprises: one right to the conveying roller that is arranged on the read point upstream side along paper feeding, wherein, is crooked from conveying roller to the paper transportation path to a pair of driven roller and driven voller.

9. feeder according to claim 1, wherein: the axis of driven voller is with respect to 1 °～3 ° of the leading-edge droops that is supplied to paper width.

10. feeder according to claim 2, wherein: the driven roller assembly has the quantity a plurality of driven roller roller sections identical with driven voller roller section.

11. a downstream paper delivering mechanism is used for carrying the recording medium that is supplied to from operating position, it comprises:

One first axle drive shaft, it is perpendicular to the direction of the supply of recording medium;

A driven roller, it is arranged on first axle drive shaft;

One second axle drive shaft, it has at least two shaft parts, and each shaft part tilts with respect to first axle drive shaft;

At least one driven voller, it is installed on each shaft part of second axle drive shaft.

12. downstream according to claim 11 paper delivering mechanism, wherein: the bevelled angle is 1 °-3 °.

13. downstream according to claim 11 paper delivering mechanism, wherein: described driven roller with respect to the friction coefficient of recording medium greater than the friction coefficient of described driven voller with respect to recording medium.

14. downstream according to claim 13 paper delivering mechanism, wherein: described driven roller is made of a plurality of roller sections identical with the quantity of described driven voller, and it is right that driven voller and driven roller roller section form a conveying.

15. downstream according to claim 11 paper delivering mechanism, wherein: described bevelled position is that the second axle drive shaft shaft part is positioned on the recording medium direction of the supply than first the axle drive shaft more upstream or the position in downstream more the end at close center, and another end of this second axle drive shaft shaft part is positioned at than this first axle drive shaft more downstream or the position of upstream more.

16. downstream according to claim 11 paper delivering mechanism, wherein: described second axle drive shaft has four shaft parts, and two innermost shaft parts tilt with respect to first axle drive shaft, and two outermost shaft parts are parallel to first axle drive shaft.

17. downstream according to claim 15 paper delivering mechanism, wherein: described second axle drive shaft has four shaft parts, and two innermost shaft parts tilt with respect to first axle drive shaft, and two outermost shaft parts are parallel to first axle drive shaft.

18. a processing equipment, the medium that its use is transferred is used for reading or print image, and it has a downstream paper delivering mechanism, and this downstream paper delivering mechanism comprises:

One first axle drive shaft, it is perpendicular to the direction of the supply of medium;

A driven roller, it is arranged on first axle drive shaft;

One second axle drive shaft, it has at least two shaft parts, and each shaft part tilts with respect to first axle drive shaft;

At least one driven voller, it is installed on each shaft part of second axle drive shaft.

19. processing equipment according to claim 18, wherein: the bevelled angle is 1 °-3 °, and described driven roller with respect to the friction coefficient of recording medium greater than the friction coefficient of described driven voller with respect to recording medium.

20. processing equipment according to claim 19, wherein: described bevelled position is that the second axle drive shaft shaft part is positioned on the medium direction of the supply than first the axle drive shaft more upstream or the position in downstream more the end at close center, and another end of this second axle drive shaft shaft part is positioned at than this first axle drive shaft more downstream or the position of upstream more.

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