JP4006291B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that reads an image of a document sheet that is being conveyed, and in particular, aims to stabilize the conveyance of the document sheet.
[0002]
[Prior art]
Conventionally, the following two methods are well known as methods for reading an image on a document used in an image reading apparatus.
[0003]
The first method is a document fixing method. In this method, a document is set on a document table by a predetermined method, and a document fixed on the document table glass is scanned by a movable optical carriage so that an image on the document is read by an image reading unit. It is. The second method is a document conveyance method. This is a method in which a document is conveyed at a predetermined conveyance speed and is read by a predetermined reading unit by a fixed optical carriage.
[0004]
In the latter document conveying method, the optical carriage can be fixed as compared with the former document fixing method, and it is not necessary to reciprocate the optical carriage every time. For this reason, the apparatus configuration is not complicated, and there is an advantage over the former document fixing method in that the processing speed is increased. Further, with the recent progress of digital processing technology in copying machines and the like, even when a plurality of copies are formed from the same document, the document can be read only once. That is, once read image information is temporarily stored as digital information in a storage medium such as a computer, it becomes easy to recreate a necessary number of copy images based on the stored image information. . Also in this respect, the superiority of the image reading by the document conveying method has been further increased.
[0005]
Further, when a document includes images on both sides thereof, two optical carriages are provided along the document transport path from the viewpoint of convenience of operation and speeding up when reading the images on both sides. There is also a reading device configured to read an image included on each side of the document. According to such an apparatus configuration, the images included on the front and back sides of the document conveyed along a predetermined path can be read and read almost simultaneously, so that the reading process in the double-sided copy of the document can be speeded up. be able to.
[0006]
As an original reading type image reading device, an automatic original feeding unit for automatically feeding and conveying an original is mounted on the upper part of an original reading type image reading unit, and the optical carriage is stopped at a predetermined position. Thus, it is common to read an image of a document conveyed on the platen glass. In such a configuration, the automatic document feeder has a function of a pressure plate that presses the document placed on the platen glass onto the platen glass, and is configured to be openable and closable with respect to the image reading unit.
[0007]
Further, in an image reading apparatus capable of reading both sides, a second optical carriage is provided in a position where the document is opposed to the first optical carriage of the document fixing and reading unit in the document automatic feeding unit. As a result, a configuration is adopted in which both sides of the document can be read almost simultaneously. In such an apparatus, the second optical carriage is also configured to be openable and closable with respect to the image reading unit integrally with the automatic document feeding unit.
[0008]
[Problems to be solved by the invention]
However, in the case of the prior art as described above, the following problems have occurred. That is, in the image reading apparatus of the document transport system as described above, disturbance of the document behavior during reading adversely affects the reading accuracy. For example, the read image may be expanded or contracted due to a change in the document conveying speed during reading or a vertical movement in the conveying path, or the image may be suddenly disturbed.
[0009]
In particular, in the case of a color scanner, each color reading element arranged in the document conveyance direction is read at a timing that matches the document conveyance speed, and is electrically superimposed to recreate a color image. . For this reason, the disturbance of the behavior of the document during conveyance appears as a color shift of the read image.
[0010]
For this reason, a document conveyance type image reading apparatus requires high accuracy for document conveyance, and the document conveyance path is configured to remove, as much as possible, elements that disturb the document behavior, such as steps. It is necessary to
[0011]
However, in the image reading apparatus having both the document fixing method and the document conveying method as described above, the image reading unit and the document feeding unit are configured to be openable and closable so that they are conveyed by the document feeding unit. When the original is guided to the image reading unit, it is inevitable that the original passes through the step of the original feeding unit.
[0012]
For this reason, when the trailing edge of the document passes through such a step, the document suddenly moves up and down, thereby disturbing the behavior of the document with respect to the optical carriage, such as the conveyance speed and position of the document. It will have an adverse effect such as color shift. In particular, there is a problem that such a phenomenon appears remarkably in a thick original with strong stiffness.
[0013]
Accordingly, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an image reading apparatus that stabilizes the conveyance of a document sheet from a document feeding unit to an image reading unit. Is to provide.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, a typical configuration of an image reading apparatus according to the present invention includes an image reading unit having a reading unit capable of reading an image of a document on a document table, and an open / close state with respect to the image reading unit. A document feeding unit that feeds a document sheet to the reading unit in a stopped state and a document feeding unit that is provided in the document feeding unit and guides the document sheet to the document reading position of the reading unit. In the image reading apparatus including the sheet conveyance path, the document feeding unit is rotatably provided, and the leading end of the document feeding unit is in contact with the image reading unit in the process of opening and closing the document feeding unit. rotates while maintaining the a guide member forming a part of the sheet conveying path, has a guide member for guiding the document sheets fed by said original feeding unit to the document reading position of said reading means The guide member is When the document feeding unit is closed, the contact state with the image reading unit is maintained on the upstream side of the document reading position in the document sheet transport direction, and the sheet transport path and the document are maintained in the contact state. It is arranged so as to be continuously connected to the reading position .
[0015]
An image reading unit having a reading unit capable of reading an image of a document on the platen, and an image reading unit that is openable and closable with respect to the image reading unit, and that supplies a document sheet to the reading unit in a stopped state. In an image reading apparatus comprising: a document feeding unit that feeds; and a sheet conveyance path that is provided in the document feeding unit and guides a document sheet to the document reading position of the reading unit. A guide member that is freely provided and rotates while maintaining a state in which the tip is in contact with the surface of the document feeding unit in the process of opening and closing the document feeding unit. A guide member that guides the fed document sheet to a document reading position of the reading unit; and the guide member is located upstream of the document reading position in the document conveyance direction when the document feeding unit is closed. The document supply Maintaining the contact state of the parts, and, in the above contact state, characterized in that it is arranged so as connect with said original reading position and the sheet conveyance path continuously.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
[First embodiment]
A first embodiment of an image reading apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of an image reading apparatus according to the present embodiment, FIG. 2 is an enlarged view of a main part of the image reading apparatus, FIG. 3 is a schematic perspective view of the image reading apparatus, and FIG. FIG.
[0017]
Note that the image reading apparatus shown in each drawing is an apparatus applicable as an image reading apparatus in a digital copying machine. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment and the following embodiments limit the scope of the present invention only to those unless otherwise specified. It is not intended.
[0018]
(overall structure)
First, the configuration of the entire image reading apparatus will be described with reference to FIGS. As shown in FIG. 1, the image reading apparatus generally includes a flatbed image reading unit (hereinafter referred to as FB1) that reads and fixes a surface of a document, and automatic feeding that is attached to the upper surface of the FB1. Device (hereinafter referred to as ADF2). A part of the FB1 and a part of the ADF2 are combined to form a document conveyance reading unit.
[0019]
The FB 1 has a mechanism for reading a surface image of a document placed and fixed. The FB 1 includes a reference original plate glass 3 that is a translucent plate material on which an original is placed. In addition, a first optical carriage A as a reading unit for reading a document is provided below the document table glass 3.
[0020]
The first optical carriage A is connected to an endless drive belt 5, and this drive belt 5 is further connected to a drive motor 6. The power of the drive motor 6 is transmitted to the first optical carriage A via the drive belt 5, so that the first optical carriage A is movable in parallel with the document table glass 3.
[0021]
The first optical carriage A is used for both the document fixing method and the document conveying method. That is, the first optical carriage A has a function of reading an image on a document placed and fixed on the platen glass 3 (fixed reading function). The first optical carriage A also has a function of reading an image on a document being conveyed (a flow reading function) while stopped at a predetermined position.
[0022]
The lamp 7 disposed on the upper surface of the first optical carriage A is a light source for irradiating light on the document. The reflected light reflected from the document is guided to the CCD 9 by the reflecting mirror 8 and the condenser lens 10. The CCD 9 is a known photoelectric conversion element that converts incident light into an electrical signal. On the platen glass 3, a document abutting reference plate 11 is provided which serves as a reference for the position of the document when placing the document on the platen glass 3.
[0023]
On the other hand, the ADF 2 includes a document stacking tray 13 serving as a document stacking unit for placing and stacking documents on the top thereof. The document on the document stacking tray 13 is regulated by the document side regulating plate 12 at both sides in the transport (feed) direction.
[0024]
The well-known document presence / absence sensor 15 recognizes the presence of the document by detecting the leading edge of the document with the lever crest. In addition, the known document length detection sensor 14 also detects the length of the document. In addition, a weight 16 for pressing the leading edge of the document fed from the document stacking tray 13 from above, and a document shutter 17 for preventing the leading edge of the document from entering the separation feeding unit are provided.
[0025]
The pickup roller 18 provided in the ADF 2 has a function of sequentially feeding stacked documents from the lowest one. The document fed out by the pickup roller 18 is conveyed to the document conveying / reading unit by the downstream feeding roller 20.
[0026]
In addition, a separation belt 19 is provided at a position facing the feeding roller 20 across the document conveyance path. The separation belt 19 is rotationally driven so as to apply a conveying force to the document in a direction opposite to the document feeding direction. In this way, the overlapped originals are separated by the separation belt 19 so that the originals are reliably sent out one by one.
[0027]
A pre-registration sensor lever 21 provided in the ADF 2 detects the leading edge of the document and measures the timing of document loop creation. The registration roller pair 22 sends the conveyed document to the reading unit at a predetermined timing. The document leading edge detection sensor 23 detects the leading edge of the document sent out by the registration roller pair 22.
[0028]
The document transport upper guide 24 is provided at a position facing the document table glass 3. The document transport upper guide 24 has a role of guiding the document to the first reading unit 25. The first reading unit 25 is set in a gap between the platen glass 3 and the document transport upper guide 24. Accordingly, the image included in the document surface (first surface) is read by the optical carriage A staying at a fixed position when the document passes through the first reading unit 25.
[0029]
The second optical carriage B as the back surface reading means is provided in a position facing the first optical carriage A and the document table glass 3 in the ADF that holds the second optical carriage B. Similar to the first optical carriage A, a reflection mirror and a CCD are arranged in the second optical carriage B. As described above, the second optical carriage B having substantially the same configuration as the first optical carriage A reads an image included in the other surface (second surface (back surface)) of the document by the second reading unit 27. . The second reading unit 27 is set slightly downstream of the first reading unit 25 in the document feeding direction on the document transport path along the document table glass 3.
[0030]
The document after passing through the first reading unit 25 and the second reading unit 27 is discharged out of the FB 1 by the discharge roller pair 33. A discharge stacking tray 32 for stacking the documents discharged by the discharge roller pair 33 is provided on the side surface of the FB 1.
[0031]
As shown in FIG. 3, the ADF 2 is configured to be openable and closable with respect to the FB 1. When the ADF 2 is opened, the sheet conveyance path is separated into upper and lower portions as shown in FIG.
[0032]
As shown in FIG. 4A, a guide flapper 28 serving as a guide member is provided for the ADF 2 at a portion where the document sent from the ADF 2 falls on the FB 1. The guide flapper 28 is provided so as to be rotatable with respect to the ADF 2 about a shaft 29. The guide flapper 28 is configured such that its tip hangs downward due to its own weight. However, the tip of the guide flapper 28 can be actively directed downward by biasing means such as a spring.
[0033]
Accordingly, the guide flapper 28 is configured to rotate while the tip end of the guide flapper 28 is in contact with the upper surface (upper surface) of the FB1 during the opening / closing operation of the ADF 2. When the ADF 2 is closed, the state where the tip of the guide flapper 28 is in contact with the upper surface of the FB 1 is maintained. The operation of the image reading apparatus configured as described above will be described below.
[0034]
(Original fixing method)
First, an operation for reading an image by the document fixing method will be described. In this case, first, the operator opens the ADF 2, places the document on the document table glass 3, and sets the document so that one end of the document is in contact with the document abutting reference plate 11. Next, the operator closes ADF2. As a result, the original is pressed and fixed to the original table glass 3 by the pressure plate 4. This also corrects the curl and the like of the original and also closely contacts the original table glass 3. Thereafter, the operator presses a document reading start button provided on an operation panel (not shown). As a result, the document reading operation is started.
[0035]
Next, a document reading operation will be described. First, the drive belt 5 starts to operate when power is supplied by the drive motor 6. As a result, the carriage A moves to a predetermined initial position. Then, the carriage A is accelerated until it reaches a predetermined speed while moving from the initial position to the document reading position. Further, after reaching the predetermined speed, the carriage A reaches the leading end position of the document abutted against the document abutting reference plate 11 while maintaining the speed. Thereafter, the carriage A moves while maintaining a predetermined speed, and reads the document. After reading the entire surface of the document, the carriage A is reversed in the direction opposite to the reading direction by the reverse drive of the drive motor 6 and returns to a predetermined standby position.
[0036]
(Original transport method)
Next, an operation for reading an image by the document conveyance method will be described. In this case, the operator first loads the document on the document stacking tray 13 of the ADF 2. At this time, the ADF 2 can know from the document length detection sensor 14 and the document presence / absence sensor 15 that the document is placed on the document stacking tray 13. Further, the operator can know the size of the document by the combination of detection with the document length detection sensor 14 by setting the document width by the document side regulating plate 12.
[0037]
Next, in the above state, the operator presses a document reading start button (not shown). Then, the document shutter 17 that restricts the leading edge of the document is opened, and the document bundle is conveyed to the document separation unit by the weight 16 and the pickup roller 18. Next, the original is separated and fed one by one by the separation belt 19 and the feeding roller 20. After the leading edge of the document reaches the registration roller pair 22 and the document forms a predetermined loop by the pre-registration sensor, the rotation of the feeding roller 20 is stopped.
[0038]
After a predetermined timing, the registration roller pair 22 starts to rotate and conveys the document. The leading edge of the conveyed document is detected by the document leading edge detection sensor 23, and the time for the document to reach the document reading position is determined. Then, the document is guided to the first reading unit 25 by the document transport upper guide 24. Then, the document passes through the first reading unit 25 at a predetermined conveyance speed. At this time, the image on one side of the document is sequentially read by the first optical carriage A while the document is being conveyed.
[0039]
In addition, the document reaches the second reading unit 27. Similarly to the above, the document passes through the second reading unit 27 at a predetermined conveyance speed. At this time, the image on the other side (back side) of the document is sequentially read by the second optical carriage B while the document is being conveyed. The leading edge of the document passes through the second reading unit 27 and is then conveyed by the discharge roller pair 33. After all the images of the document are read, the document is discharged onto the discharge stacking tray 32. The above is a series of operation modes when performing both-side reading of a document.
[0040]
Next, the operation of the guide flapper 28 will be described. In the state where the ADF 2 is opened, the guide flapper 28 has its tip positioned downward as shown in FIG.
[0041]
When the ADF 2 is closed as shown in FIG. 4 (b), the tip of the guide flapper 28 comes into contact with the FB1. Then, the guide flapper 28 is rotated about the shaft 29, so that the leading end of the guide flapper 28 is in contact with the FB1, and is rotated to a proper position to form a sheet conveyance path.
[0042]
At this time, since the tip of the guide flapper 28 is in contact with the FB1, the step between the ADF2 and the FB1 is smoothly connected. Accordingly, it is possible to suppress the vertical movement of the document that occurs when the trailing edge of the document falls on the stepped portion. In addition, since the guide flapper 28 is configured to be rotatable about the shaft 29, the tip of the guide flapper 28 can be moved even if there is a difference in airframe between the ADF 2 and the FB 1 caused by variations in parts and assembly. Since it always hits the FB1, it is possible to eliminate the step in the sheet conveyance path.
[0043]
As described above, the conveyance stability of the document is improved, and the quality of the read image can be improved. In particular, in the case of reading a color image, the color shift of the image can be suppressed.
[0044]
[Second Embodiment]
A second embodiment of the image reading apparatus according to the present invention will be described with reference to the drawings. FIG. 5 is an enlarged cross-sectional view of the characteristic part of the image reading apparatus according to the present embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
[0045]
In the first embodiment, the configuration in which the guide flapper 28 serving as the guide member is provided in the ADF 2 serving as the document feeding unit has been described. On the other hand, this embodiment demonstrates the structure which provided the guide member in FB1 side which is an image reading part.
[0046]
As shown in FIG. 5, a guide flapper 30 that is a guide member for FB1 is provided at the step portion between FB1 and ADF2. The guide flapper 30 is provided so as to be rotatable with respect to the FB 1 about the shaft 31.
[0047]
The tip of the guide flapper 30 is urged upward by a spring (not shown) as urging means. Thus, the ADF 2 is located at an upward angle when the ADF 2 is open. On the other hand, when the ADF 2 is closed, the ADF 2 is pushed by the ADF 2 and rotates about the shaft 31 to form a sheet conveyance path in a state where the ADF 2 hits the ADF 2.
[0048]
With such a configuration, the tip of the guide flapper 30 can be reliably brought into contact with the ADF 2, and the step between the ADF 2 and the FB 1 can be smoothly connected as in the first embodiment. , The behavior of the document can be stabilized.
[0049]
Therefore, as in the case of the first embodiment, the document transport stability can be improved, and the quality of the read image can also be improved. In particular, in the case of reading a color image, the color shift of the image can be suppressed.
[0050]
Further, the guide flapper 30 can also function as the document abutting reference plate 11 when the document fixing method is read by the FB1. That is, the front end surface of the guide flapper 30 can function as a reference surface of the end portion of the document, and the number of parts can be reduced.
[0051]
[Third embodiment]
A third embodiment of the image reading apparatus according to the present invention will be described with reference to the drawings. FIG. 6 is a perspective view of the characteristic part of the image reading apparatus according to the present embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0052]
In the present embodiment, a configuration will be described in which the guide flapper 28 described as the guide member in the first embodiment is divided into a plurality of parts in a direction perpendicular to the document conveyance direction. It should be noted that the guide flapper 30 described as the guide member in the second embodiment can be similarly divided and provided.
[0053]
As shown in FIG. 6, a plurality of guide flappers 34a and 34b are provided in the step portion between FB1 and ADF2 in a direction perpendicular to the document conveyance direction. These guide flappers 34a and 34b are provided so as to be independently rotatable with respect to the ADF 2 around a shaft 35 indicated by a one-dot chain line in FIG.
[0054]
Further, the guide flappers 34a and 34b are configured such that their tips hang downward by an urging means such as its own weight or a spring. Accordingly, the guide flappers 34a and 34b are rotated while the tips of the guide flappers 34a and 34b are in contact with the upper surface of the FB1 in the process of opening and closing the ADF 2.
[0055]
The guide flapper is divided into a plurality of directions perpendicular to the document conveyance direction, and each of the guide flappers is configured to be independently rotatable. Therefore, each end of each of the guide flappers 34a and 34b when the ADF 2 is closed. Is rotated so as to maintain a state of being in contact with the upper surface of the FB1.
[0056]
Therefore, when the amount of step between FB1 and ADF2 is not constant in the document transport direction, the step is smoothed by bringing the guide flappers 34a and 34b into contact with the upper surface of FB1 more reliably than in the first embodiment. Therefore, the behavior of the document can be further stabilized.
[0057]
In this embodiment, the guide flapper is divided into two parts in the document transport direction. However, the guide flapper may be divided into three or more parts so as to be independently rotatable.
[0058]
【The invention's effect】
As described above, the image reading apparatus according to the present invention can maintain the state in which the leading end of the guide member is in contact with the opposed document feeding unit or the image reading unit by the rotatable guide member. It is possible to stabilize the conveyance state of the sheet and improve the quality of the read image.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an image reading apparatus according to a first embodiment.
FIG. 2 is an enlarged view of a main part of the image reading apparatus.
FIG. 3 is a schematic perspective view of an image reading apparatus.
FIG. 4 is an enlarged cross-sectional view of a characteristic portion in the image reading apparatus.
FIG. 5 is an enlarged cross-sectional view of a characteristic part of the image reading apparatus according to the second embodiment.
FIG. 6 is a perspective view of a characteristic part of an image reading apparatus according to a third embodiment.
[Explanation of symbols]
A ... First optical carriage B ... Second optical carriage 1 ... FB
2 ... ADF
3 ... reference platen glass 4 ... pressure plate 5 ... drive belt 6 ... drive motor 7 ... lamp 8 ... reflection mirror 9 ... CCD
10… Condensing lens
11 ... Document reference plate
12… Original side regulating plate
13 ... Document stacking tray
14… Detection sensor
15 ... Document presence sensor
16… weight
17… Original shutter
18… Pickup roller
19… Separation belt
20 ... Feed roller
21… Sensor lever before registration
22… Registration roller pair
23… Document tip detection sensor
24 ... Document transport upper guide
25… First reading section
27… Second reading section
28… Guide flapper
29… axis
30… Guide flapper
31… axis
32… discharge loading tray
33… discharge roller pair
34a… Guide flapper
34b… Guide flapper
35… axis

Claims (11)

An image reading unit having reading means capable of reading an image of a document on a document table;
A document feeding unit that is provided so as to be openable and closable with respect to the image reading unit, and that feeds a document sheet to the reading unit in a stopped state;
A sheet conveyance path that is provided in the document feeding section and guides a document sheet to the document reading position of the reading unit;
In an image reading apparatus comprising:
One of the sheet conveyance paths, which is rotatably provided in the document feeding unit and rotates while maintaining a state in which the leading end is in contact with the image reading unit in the process of opening and closing the document feeding unit. A guide member that forms a section, the guide member that guides a document sheet fed by the document feeding section to a document reading position of the reading unit ,
The guide member maintains a contact state with the image reading unit on the upstream side of the document reading position in the document sheet conveying direction when the document feeding unit is closed, and in the contact state, An image reading apparatus , wherein a sheet conveying path and the document reading position are continuously connected . The image reading apparatus according to claim 1, wherein a plurality of the guide members are provided in a direction orthogonal to a document conveyance direction, and each of the guide members is independently rotatable with respect to the document feeding unit.   The image reading apparatus according to claim 1, wherein the guide member maintains a contact state of the guide member with a surface of the image reading unit by the weight of the guide member. An image reading unit having reading means capable of reading an image of a document on a document table;
A document feeding unit that is provided so as to be openable and closable with respect to the image reading unit, and that feeds a document sheet to the reading unit in a stopped state;
A sheet conveyance path that is provided in the document feeding section and guides a document sheet to the document reading position of the reading unit;
In an image reading apparatus comprising:
A guide member that is rotatably provided in the image reading unit and rotates while maintaining a state in which a tip thereof is in contact with the surface of the document feeding unit in the process of opening and closing the document feeding unit; A guide member for guiding the document sheet fed by the document feeding unit to the document reading position of the reading unit ;
The guide member maintains a contact state with the document feed unit on the upstream side of the document reading position in the document transport direction when the document feed unit is closed, and in the contact state, An image reading apparatus , wherein a sheet conveying path and the document reading position are continuously connected . The image reading apparatus according to claim 4, wherein a plurality of the guide members are provided in a direction orthogonal to the document conveyance direction, and are independently rotatable with respect to the image reading unit.   The image reading apparatus according to claim 4, further comprising an urging unit that urges a leading end of the guide member toward a surface of the document feeding unit.   The image reading apparatus according to claim 4, wherein the guide member includes a guide surface for positioning a document placed on the document table.   The image reading apparatus according to claim 1, wherein the document feeding unit has a cover function that covers a document placed on the document table.   2. The back side reading unit for reading an image on a surface opposite to a side read by the reading unit of a sheet fed by the document feeding unit in the document feeding unit. The image reading apparatus according to claim 8.   The image reading apparatus according to claim 1, wherein the reading unit reads an image of a document placed on the document table while moving in parallel with the document table.   11. The image reading according to claim 1, wherein the reading unit reads an image of a document sheet fed by the document feeding unit while stopped at a predetermined position. apparatus.

Images