JP2007329769A - Image reader, laser beam printer loaded with the same, facsimile, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader capable of improving the durability of a dirt-preventing effect by changing a carrying route of a recording medium in accordance with a paper feeding mode, a laser printer loaded with the image reader and an image forming apparatus such as a facsimile. <P>SOLUTION: The image reader provided with a separation part B for separating recording media one by one, carrying means 12, 14 for carrying each separated recording medium to a reading/carrying part, a first surface reading part E for reading out the first surface of the carried recording medium, a second reading part F for reading out the second surface of the recording medium, a guide means 26 movably arranged oppositely to a reading unit 25 of the second surface reading part F and having a function to be a reference for shading, and a driving means 34 for driving the carrying means 12, 14 includes distance variable devices 44 to 49 capable of changing a distance between the fixed reading unit 25 and the shading member 26. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that conveys, reads and discharges a recording medium (original) in an image forming apparatus such as a copying machine, and an image forming apparatus such as a laser printer and a facsimile equipped with the image reading apparatus.

In an image forming apparatus such as a copying machine, in a sheet-through DF that performs reading while a reading unit is fixed and a recording medium (original) is conveyed, an abnormal image (streaked image) is observed when foreign matter stays and adheres to the reading unit. In order to eliminate this inconvenience, several techniques are known (for example, see Patent Documents 1 and 2).
In order to solve the above inconvenience, Patent Document 1 discloses a configuration in which a guide member on a reading position is rotatable. Further, Patent Document 2 discloses a configuration in which a guide plate having a shading function that is not partially circular is used by being divided into a shading surface and a conveyance surface.
JP 2001-238047 A JP 2002-51194 A

Further, in order to solve the problem that an abnormal image (streaked image) appears when foreign matter stays and adheres to the reading unit, a technique in which antifouling processing is performed on the reading position is also known. Since the recording medium comes into contact with the reading position, there is a problem that the antifouling effect is reduced in proportion to the number of times the recording medium passes.
SUMMARY OF THE INVENTION An object of the present invention is to improve the durability of the antifouling effect by changing the conveyance path of the recording medium according to the paper passing mode, and to form an image such as a laser printer and a facsimile equipped with the image reading apparatus. To provide an apparatus.

In order to solve the above-described problems, the invention described in claim 1 includes a separation unit that separates the recording media one by one, a conveyance unit that conveys the separated recording medium to the reading conveyance unit, and a conveyance unit A first surface reading unit that reads the first surface of the recording medium, a second surface reading unit that reads the second surface of the recording medium, and a reading unit of the second surface reading unit are arranged and movable. A distance variable device capable of changing a distance between the fixed reading unit and the guide means in an image reading apparatus provided with guide means having a reference function during shading and drive means for driving the transport means. An image reading apparatus having a configuration including the above is characterized.
According to a second aspect of the present invention, there is provided the image reading apparatus according to the first aspect, wherein the distance between the reading unit and the guide unit is changed using a driving unit.
According to a third aspect of the present invention, there is provided the image reading apparatus according to the second aspect, wherein the number of the driving means is one.
According to a fourth aspect of the present invention, there is provided the image reading apparatus according to any one of the first to third aspects, wherein the change in the distance between the reading unit and the guide means is performed corresponding to a reading mode. Features.
According to a fifth aspect of the present invention, the distance between the reading unit and the guide means is changed by supporting / pressurizing the vicinity of both ends of the guide means. It features an image reading device.
According to a sixth aspect of the present invention, the distance between the reading unit and the guide means is changed by supporting / pressurizing the vicinity of the center of the guide means. It features an image reading device.

According to a seventh aspect of the present invention, there is provided the image reading device according to the fifth or sixth aspect, wherein the connecting member that connects the plurality of supporting / pressurizing members is made of metal.
The invention according to claim 8 is the image reading device according to claim 7, wherein the plurality of pressure members rotate about the connecting member that connects these pressure members.
According to a ninth aspect of the present invention, the distance from the fulcrum to the point at which the pressure member presses the guide means is shorter than the point at which the pressure member is pressed from the fulcrum by the driving means. 8 is an image reading apparatus.
According to a tenth aspect of the present invention, there is provided a laser beam printer equipped with the image reading device according to any one of the first to ninth aspects.
The invention described in claim 11 is characterized by a facsimile equipped with the image reading apparatus described in any one of claims 1-9.
According to a twelfth aspect of the present invention, there is provided an image forming apparatus including the image reading apparatus according to any one of the first to ninth aspects.

  According to the present invention, since the distance between the reading unit and the guide means is variable, the conveyance path can be changed depending on the mode, and the durability of the antifouling performance of the reading unit can be improved without affecting the quality. . Since the distance between the reading unit and the guide means (shading agent) is variable, the transport path can be changed depending on the mode, and the antifouling performance of the reading unit can be improved without affecting the quality. .

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the overall configuration of an automatic document feeder. FIG. 2 is a block diagram showing a drive control unit of the automatic document feeder shown in FIG.
FIG. 1 shows an automatic document conveying apparatus or a read recording medium processing apparatus (hereinafter referred to as ADF) used in an apparatus for reading an image while conveying a read recording medium (original) to a fixed reading unit at a predetermined speed. And a reading unit.
The basic configuration, operation, and action will be described below with reference to FIG. The ADF includes a recording medium setting unit A for setting a double-sided recording medium bundle to be read, a separation feeding unit B for separating and feeding recording media (originals) one by one from the set double-sided recording medium bundle, It includes a resist portion C having a function of primarily abutting and aligning the surface of the recorded recording medium and a function of pulling out and transporting the aligned recording medium.
Further, the ADF turns a recording medium to be conveyed and turns the recording medium surface toward the reading side (downstream side), and a first surface for reading an image on the recording medium from below the contact glass. And a second surface reading / conveying unit F for reading the second surface of the recording medium after reading the first surface.
Further, the ADF includes a paper discharge unit G that discharges the recording medium whose second surface is read by the second surface reading unit F unit, and a stack unit H that stacks and holds the recording medium after reading is completed. It is out.
Furthermore, as shown in FIG. 2, the ADF includes drive units 33 to 37 and 38 that drive the above-described transport operation, and a controller unit 39 that controls a series of operations.

A main body portion 50 covered with the contact glass 21 under the ADF is disposed below the reading position 20 of the reading conveyance unit E on the first surface, and is not shown in the drawing / writing device, imaging device, and paper feeding device. And an image forming apparatus such as a laser printer and a facsimile provided with an operation unit and a main body control unit.
The recording medium bundle 1 to be read is set on the recording medium table 2 including the movable recording medium table 3 with the recording medium surface facing upward. Further, the width direction of the recording medium bundle 1 is positioned in a direction orthogonal to the transport direction by a side guide (not shown). A set of recording media is detected by the set filler 4 and the set sensor 5 and transmitted to the main body control unit 41 by the I / F 40.
Further, the recording medium length detection sensor 30 or 31 provided on the surface of the recording medium table 3 (a reflection type sensor or an actuator type sensor that can detect even one recording medium is used) conveys the recording medium. An approximate length is determined. In this case, a sensor arrangement that can determine at least whether the size of the recording medium is vertical or horizontal is required.

The movable recording medium table 3 can be moved up and down in the a and b directions shown in FIG. 1 by a bottom plate raising motor 37 (FIG. 2). When the set filler 4 and the set sensor 5 detect that the recording medium is set, the bottom plate raising motor 37 is rotated forward to raise the movable recording medium table 3 so that the uppermost surface of the recording medium bundle contacts the pickup roller 7. Let
The pickup roller 7 is moved in the c and d directions shown in the figure by a cam mechanism (not shown) by a pickup motor 33, and the movable recording medium table 3 is raised and pushed by the upper surface of the recording medium on the movable recording medium table 3. Then, it goes up in the direction c, and the upper limit can be detected by the table rise detection sensor 8.
When the print key is pressed by the main body operation unit 43 and a recording medium paper feed signal is transmitted from the main body control unit 41 to the ADF control unit 39 via the I / F 40 via the I / F 42, the pickup roller 7 feeds paper. The motor 34 is rotationally driven by normal rotation to pick up several (ideally, one) recording media on the recording medium table 2.
The rotation direction is a direction in which the uppermost recording medium is conveyed to the paper feed port. The paper feeding belt 9 is driven in the paper feeding direction by the normal rotation of the paper feeding motor 34, and the reverse roller 10 is driven to rotate in the reverse direction to the paper feeding by the normal rotation of the paper feeding motor 34. The recording medium is separated, and only the top recording medium can be fed.

More specifically, when the reverse roller 10 is in contact with the paper feed belt 9 at a predetermined pressure and is in direct contact with the paper feed belt 9 or in a state of being in contact with one sheet of recording medium, the reverse roller 10 If the recording medium enters between the sheet feeding belt 9 and the reverse roller 10 in the unlikely event that the recording medium is rotated counterclockwise by the rotation, the rotation force is lower than the torque of the torque limiter. Is set.
The reverse roller 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an excess recording medium, thereby preventing double feeding. The recording medium separated into one sheet by the action of the paper feed belt 9 and the reverse roller 10 is further fed by the paper feed belt 9, the leading end is detected by the abutting sensor 11, and the pull-out roller 12 is further stopped. I hit it.
Thereafter, the recording medium is fed by a distance corresponding to a predetermined amount determined from the detection of the abutting sensor 11, and as a result, the recording medium is fed while being pressed against the pull-out roller 12 with a predetermined amount of deflection. By stopping the motor 34, the driving of the paper feed belt 9 is stopped.
At this time, by rotating the pickup motor 33, the pickup roller 7 is retracted from the upper surface of the recording medium, and the recording medium is fed only by the conveying force of the paper feeding belt 9, so that the leading end of the recording medium is a pair of upper and lower rollers of the pull-out roller 12. The tip is aligned (skew correction).

The pull-out roller 12 has a skew correction function and is a roller for transporting the skew-corrected recording medium to the intermediate roller 14 after separation, and is driven by the reverse rotation of the paper feed motor 34. At this time (when the paper feed motor 34 is reversely rotated), the pull-out roller 12 and the intermediate roller 14 are driven, but the pickup roller 7 and the paper feed belt 9 are not driven.
A plurality of recording medium (document) width sensors 13 are arranged in the depth direction and detect the size in the width direction orthogonal to the conveying direction of the recording medium conveyed by the pull-out roller 12. Further, the length of the recording medium in the transport direction is detected from the motor pulse by reading the leading and trailing ends of the recording medium with the abutment sensor 11.
When the recording medium is conveyed from the registration unit C to the turn unit D by driving the pull-out roller 12 and the intermediate roller 14, the conveyance speed in the registration unit C is set to be higher than the conveyance speed in the reading conveyance unit E. Thus, the processing time for feeding the recording medium to the reading and conveying section E is shortened.

When the leading edge of the recording medium is detected by the reading inlet sensor 15, before the leading edge of the recording medium enters the nip between the upper and lower roller pairs of the reading inlet roller 16, the recording medium is decelerated to make the recording medium conveying speed the same as the reading conveying speed. Start.
At the same time, the reading inlet motor 35 is driven to rotate forward to drive the reading inlet roller 16, and the reading outlet motor 38 is driven to rotate forward to drive the reading outlet roller 23.
When the registration sensor 17 detects the leading edge of the recording medium, the registration sensor 17 decelerates over a predetermined conveyance distance, temporarily stops before the reading position 20, and transmits a registration stop signal to the main body control unit 41 via the I / F 40. .
Subsequently, when a reading start signal is received from the main body control unit 41, the recording medium that has been stopped in registration is accelerated and conveyed so as to rise to a predetermined conveying speed until the leading edge of the recording medium reaches the reading position 20. .
At the timing when the leading edge of the recording medium detected by the pulse count of the reading inlet motor 35 reaches the first surface reading and conveying unit E, the main body control unit 41 is instructed until the trailing edge of the recording medium passes through the first surface reading and conveying unit E. Then, a gate signal indicating the effective image area in the sub-scanning direction on the first surface is transmitted.
During the reading of the first surface of the recording medium, the relationship between the linear velocities is within a linear velocity difference of 1%, and the relationship of the reading inlet roller 16 linear velocity ≦ the reading outlet roller 23 linear velocity. In the case of single-sided recording medium reading, since the second side is not read, the distance between the second side reading unit 25 and the guide member 26 having a shading reference function is 0.5 mm or more, and the recording medium is placed on the second side as much as possible. Do not touch the reading unit 25.

FIG. 3 is a schematic perspective view showing the distance variable device for changing the distance between the second surface reading unit and the shading member (guide means) according to the present invention in a state separated from the second surface reading unit. FIG. 4 is a schematic perspective view showing the distance variable device of FIG. 3 in a state of being brought close to the second surface reading unit.
The distance variable device is a guide member 26 that is a shading member disposed under the second surface reading unit 25 indicated by a chain line, and is disposed at one end in the longitudinal direction of the guide member 26 in a direction orthogonal thereto and the cam 44. The lever 45 pushed down by the lever 45, the lever 47 disposed at the end portion of the guide member 26 so as to face the lever 45, the shaft 46 made of metal as a connecting member for connecting the levers 45, 47, and the guide member 26 It is composed of compression springs 48 and 49 that elastically support lower portions at both ends.
The distance variable device rotates a cam 44 appropriately disposed at a position in contact with the lever 45 shown in FIG. 3 by a motor (not shown), pressurizes the lever 45, and pushes down the lever 45 about the shaft 46. The rotation angle of a motor (not shown) is controlled by a sensor (not shown) and rotates by an appropriate amount.

When the cam 44 pushes down the lever 45, the guide member 26 which is a shading member is pushed down. The coupling between the lever 45 and the shaft 46 and between the lever 47 and the shaft 46 is not shown, but each has a coupling shape such as a D-cut.
The rotation of the lever 45 by the cam 44 is transmitted to the lever 47 through the shaft 46, and the distance between the guide member 26 and the second surface reading unit 25 is increased as shown in FIG. In this configuration, the guide member 26 is supported and pressed at both ends, but it is also possible to support and pressurize the vicinity of the central portion of the guide member 26.
The relationship between the linear velocities during the reading of the first surface of the recording medium is within 1% of the linear velocity difference, and the relationship is “the first reading exit roller 23 linear velocity ≦ the second reading exit roller 27 linear velocity”. It has no configuration. The recording medium that has passed through the second surface reading conveyance unit F is conveyed to the paper discharge unit G.
At this time, when the front end of the recording medium is detected by the paper discharge sensor 24, the paper discharge motor 36 is driven to rotate forward to rotate the paper discharge roller 28 counterclockwise. Further, by the discharge motor pulse count from the detection of the leading edge of the recording medium by the discharge sensor 24, the discharge motor driving speed is reduced immediately before the trailing edge of the recording medium comes out of the nip of the upper and lower roller pairs of the discharge roller 28, Control is performed so that the recording medium discharged onto the paper discharge tray 29 does not jump out.

When reading a double-sided recording medium, the distance between the second surface reading unit 25 and the guide member 26 having a shading reference function is set to about 0.2 mm, and the recording medium is brought into contact with the second surface reading unit 25.
At that time, the cam 44 is rotated by a motor (not shown), and the force to push down the lever 45 about the shaft 46 is released. The rotation angle of a motor (not shown) is controlled by a sensor (not shown) and rotates by an appropriate amount.
As described above, although not shown, by providing a driving means, that is, a motor, the second surface reading unit 25 and the shading member 26 are automatically linked to mode information, that is, mode information for single-sided or double-sided reading. Can change the distance.
Thereby, the conveyance path can be changed depending on the mode, and the durability of the antifouling performance of the second surface reading unit 25 can be improved without affecting the quality. In this case, if the motors are combined into one, it is possible to save power.

When the cam 44 releases the force to push down the lever 45, the guide member 26, which is a shading member, approaches the second surface reading unit 25 by the compression springs 48 and 49, and the distance between them becomes narrow as shown in FIG. .
In this manner, the distance between the second surface reading unit and the shading member 26 is changed by supporting / pressurizing the vicinity of both ends of the shading member 26. A plurality of support / pressure members, that is, a shaft 46 which is a member connecting the levers 45 and 47 is made of metal. Therefore, sufficient strength can be ensured.
Further, the plurality of pressure members, that is, the levers 45 and 47 rotate with a shaft 46 connecting them as a fulcrum. The distance from the fulcrum to the point where the levers 45, 47 press the shading member 26 is shorter than the point from the fulcrum where the levers 45, 47 are pressed by driving means (not shown).

The relationship between the linear velocities during the reading of the first surface of the recording medium is such that the linear velocity difference is within 1%, and the first reading exit roller 23 linear velocity ≧ second reading exit roller 27 linear velocity is set to bend. The recording medium that has passed through the second surface reading conveyance unit F is conveyed to the paper discharge unit G.
At this time, when the front end of the recording medium is detected by the paper discharge sensor 24, the paper discharge motor 36 is driven to rotate forward to rotate the paper discharge roller 28 counterclockwise. Further, by the discharge motor pulse count from the detection of the leading edge of the recording medium by the discharge sensor 24, the discharge motor driving speed is reduced immediately before the trailing edge of the recording medium comes out of the nip of the upper and lower roller pairs of the discharge roller 28, Control is performed so that the recording medium discharged onto the paper discharge tray 29 does not jump out.
By mounting the image reading apparatus provided with the above-described variable distance device according to the present invention in an image forming apparatus such as a laser printer or a facsimile, the antifouling performance of the second surface reading unit 25 can be improved, and foreign matter Abnormal images can be reduced for a long period of time.

1 is a schematic diagram illustrating an overall configuration of an automatic document feeder. FIG. 2 is a block diagram illustrating a drive control unit of the automatic document feeder in FIG. 1. It is a schematic perspective view which shows the distance variable apparatus which changes the distance of the 2nd surface reading unit and shading member by this invention in the state separated from the 2nd surface reading unit. It is a schematic perspective view which shows the state variable apparatus of FIG. 3 in the state which was made to adjoin to the 2nd surface reading unit.

Explanation of symbols

ADF Automatic document feeder (reading medium processing device)
B Separator E First surface reader F Second surface reader 12 Conveying means (conveying roller)
14 Conveying means (intermediate roller)
25 Second surface reading unit 26 Guide means (shading member, guide member)
34 Drive means (paper feed motor)
44 Variable distance device (cam)
45 Distance variable device (lever)
46 Distance variable device connecting member (connecting member, shaft)
47 Distance variable device (lever)
48 Distance variable device (compression spring)
49 Variable distance device (compression spring)
50 Image forming equipment (laser printer, facsimile)

Claims (12)

  A separation unit that separates the recording medium one by one, a conveyance unit that conveys the separated recording medium to the reading conveyance unit, a first surface reading unit that reads a first surface of the conveyed recording medium, and a recording medium A second surface reading unit that reads the second surface, a guide unit that is disposed opposite to the reading unit of the second surface reading unit and that is movable and serves as a reference function during shading correction; and An image reading apparatus comprising: a driving unit that drives the image reading apparatus, wherein the image reading apparatus includes a variable distance device that changes a distance between the reading unit and the guide unit.   2. The image reading apparatus according to claim 1, wherein a distance between the reading unit and the guide unit is changed using a driving unit.   The image reading apparatus according to claim 2, wherein the number of the driving units is one.   The image reading apparatus according to claim 1, wherein a change in the distance between the reading unit and the guide unit is performed in accordance with a reading mode.   5. The image reading apparatus according to claim 1, wherein a distance between the guide unit and the reading unit is changed by supporting / pressing the vicinity of both ends in the longitudinal direction. 6.   5. The image reading apparatus according to claim 1, wherein the distance between the reading unit and the guide unit is changed by supporting / pressurizing the vicinity of the center of the guide unit. 6.   7. The image reading apparatus according to claim 5, wherein the connecting member that connects the plurality of support / pressure members is made of metal.   The image reading apparatus according to claim 7, wherein the plurality of pressure members rotate about the connecting member that connects the pressure members.   9. The image reading apparatus according to claim 8, wherein a distance from the fulcrum to a point where the pressure member presses the guide unit is shorter than a point where the pressure member is pressed from the fulcrum by a driving unit. .   A laser beam printer comprising the image reading apparatus according to claim 1.   A facsimile, comprising the image reading device according to any one of claims 1 to 9.   An image forming apparatus comprising the image reading apparatus according to claim 1.

Images