Image reading apparatus and recording apparatus

Abstract

To provide an image reading apparatus configured to improve the quality of reading a large-size document.SOLUTION: An image reading apparatus comprises: a first conveyance roller for conveying a document in a conveyance direction; a first sensor unit arranged downstream of the first conveyance roller in the conveyance direction to read the document; a second sensor unit arranged downstream of the first sensor unit to read the document; and a second conveyance roller arranged downstream of the second sensor unit in the conveyance direction to convey the document. The image reading apparatus includes an intermediate roller arranged between the first conveyance roller and the second conveyance roller in the conveyance direction to convey the document. The conveyance speed of the second conveyance roller is higher than the conveyance speed of the first conveyance roller. The conveyance speed of the intermediate roller is equal to or higher than the conveyance speed of the first conveyance roller and lower than the conveyance speed of the second conveyance roller.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image reading device that conveys an original and reads an image therefrom, and a recording device. [Background technology]

[0002] Patent Document 1 describes an image reading device that reads images on large-sized documents such as A0 and A1 while transporting them. Line sensors that read the images are arranged in a staggered pattern at two reading positions in the transport direction. Meanwhile, drive rollers that transport the document are also arranged in a staggered pattern in the opposite phase to the line sensors at two reading positions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-203840 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration as disclosed in Patent Document 1, when two rows of drive rollers in the transport direction transport a document at the same speed, the document may bend. When the document is bent, the quality of the read image decreases. [Means for solving the problem]

[0005] The image reading device of the present invention is an image reading device comprising a first transport roller that transports a document in a transport direction, a first sensor unit that is arranged downstream of the first transport roller in the transport direction and reads the document, a second sensor unit that is arranged downstream of the first sensor unit and reads the document, and a second transport roller that is arranged downstream of the second sensor unit in the transport direction and transports the document, and is characterized in that it also comprises an intermediate roller that is arranged between the first transport roller and the second transport roller in the transport direction and transports the document, wherein the transport speed by the second transport roller is greater than the transport speed by the first transport roller, and the transport speed by the intermediate roller is greater than or equal to the transport speed by the first transport roller and less than the transport speed by the second transport roller. Effect of the Invention

[0006] According to the present invention, it is possible to provide an image reading device that improves the reading quality of a large-sized document. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of a sheet-fed scanner. [Diagram 2] FIG. 1 is a diagram illustrating a configuration of an image reading device. [Diagram 3] FIG. 2 is a block diagram showing a hardware configuration of the image reading apparatus. [Figure 4] 3A and 3B are diagrams illustrating a state in which a document is transported in the image reading device. [Diagram 5] FIG. 11 is a flowchart showing a sequence before starting to read an image. [Figure 6] FIG. 11 is a flow chart showing a sequence after the start of image reading. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the mode for carrying out the present invention will be described based on the examples with reference to the drawings. Note that the dimensions, materials, shapes, and relative positions of the components described in the embodiments may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. In other words, it is not intended to limit the scope of the present invention to the following embodiments.

[0009] <First Example> (Configuration of image reading device) 1 is a perspective view of a sheet-fed scanner 100 that reads an image while transporting a document. Scanner 100, which is an image reading device, has a supply port 101 for supplying document 200 on the front side, and a supply table 102 on which document 200 is placed. A user places the leading end of document 200 on supply table 102 so that the center of document 200 is located at the center of supply port 101. Next, the user inserts document 200 into supply port 101 while sliding it on supply table 102 in the transport direction. Note that supply port 101 allows a certain degree of misalignment and inclination in the width direction of readable document 200 when inserted.

[0010] The scanner 100 has a housing with a pivotable top cover 104 on the top surface. A user can access the transport path and the reading unit by opening the top cover 104 upward. The scanner 100 has an operation unit / display unit 103 on the top surface of the housing, outside the top cover 104 in the width direction of the document 200. The operation unit / display unit 103 may be divided into an operation unit 407 and a display unit 408, which will be described later. The operation unit / display unit 103 is composed of physical keys, a touch panel, a Liquid Crystal Display Panel (hereinafter, LCD), and the like. A user can set the reading conditions by the operation unit 407, and can check the status of the device by the display unit 408. In the coordinate system, the width direction of the document is the x direction, the transport direction of the document is the y direction, and the up-down direction is the z direction, as shown in FIG. 1.

[0011] FIG. 2 is a schematic diagram showing the transport path of the original 200. FIG. 2(a) is a cross-sectional view, and FIG. 2(b) is a top view. The original 200 is inserted from the supply tray 102 on the front side, transported in the transport direction (y direction) by the transport means, and discharged from the discharge port on the rear side. A plurality of rollers, which are transport means, are arranged on the transport path along which the original 200 is transported. They are arranged in the order of the upstream transport roller 203, the intermediate roller 204, the intermediate roller 205, and the downstream transport roller 210 from the supply port 101 side. Each roller transports the original 200 by clamping the original 200 at a clamping position using a roller pair of two rollers. In the roller pair, the upper roller is driven by the drive of the lower roller. The original detection sensor 201 that detects the original 200 is arranged on the supply tray 102 side with respect to the upstream transport roller 203, and detects the inserted original 200. An edge detection sensor 202 that detects the edge of the original 200 is disposed on the side of the intermediate roller 204 with respect to the upstream conveying roller 203, and detects the leading or trailing edge of the original 200. The original detection sensor 201 and the edge detection sensor 202 irradiate light onto the original 200 and detect the presence or absence of the original by receiving the light reflected from the original 200. However, these sensors are not limited to optical sensors and may be mechanical sensors.

[0012] The image reading device may be a multifunction machine equipped with a recording unit that records the read image or the image based on the recording data. The multifunction machine further includes a storage unit that stores the recording medium, a transport unit that transports the recording medium from the storage unit, and a recording unit that records on the recording medium transported by the transport unit. The recording unit records the image on the recording medium by an electrophotographic method, an inkjet method, or the like.

[0013] The reading unit that reads the original 200 is disposed on the conveying path. The reading unit is composed of a plurality of line sensor units that are physically separated from each other. The line sensor unit is, for example, a contact type line image sensor (CIS), and light emitted from a light source is reflected by the original 200 and forms an image on the line image sensor. Each line sensor unit 207 (1 to 3) has a plurality of light receiving elements arranged in the main scanning direction (x direction). The width of each line sensor unit 207 (1 to 3) is shorter than the width of the original. Therefore, images read by each line sensor unit 207 (1 to 3) are joined together to form a single image. Each line sensor unit 207 (1 to 3) is arranged in a staggered arrangement alternately at one of two rows of reading positions on the upstream side and downstream side separated in the conveying direction (y direction) of the original 200. Here, the explanation will be given on the premise that the branch numbers (1 to 3) of the line sensor units 207 increase as they proceed in the x direction. The line sensor unit 207-2 is disposed at a reading position on the upstream side, and the line sensor unit 207-1 and the line sensor unit 207-3 are disposed at a reading position on the downstream side. When the reading ranges of the line sensor units 207 (1 to 3) are projected onto the x-axis, a part of the reading ranges of the adjacent line sensor units 207 (1 to 3) overlap each other. The overlapping part of the reading ranges becomes a seam (DB) of each image data. In this embodiment, three line sensor units 207 (1 to 3) are disposed in the width direction. However, the number of line sensor units is not limited to three, and may be five or more, as long as the number of units is staggered. Also, the number of units may be an even number, not limited to an odd number, at each reading position.

[0014] Here, each roller will be described. The upstream transport roller 203 and the downstream transport roller 210 extend beyond the width of the document. Each roller is driven by a drive motor 211. In order to transmit the drive of the drive motor 211, the downstream transport roller 210, the intermediate roller 205, and the drive motor 211 are wound around each rotation shaft by a single belt 212. In addition, tension is applied to the belt 212 by a tension application mechanism 213. The downstream transport roller 210 can transport the document 200 at a transport speed higher than that of the intermediate roller 205 by changing the gear diameter or roller diameter. The downstream transport roller 210 may be driven by a motor different from that of the intermediate roller 205. In this case, the transport speed of the downstream transport roller 210 and the intermediate roller 205 can be freely changed. In addition, the lower transport roller 210 and the intermediate roller 205 may be connected by a gear. The transport speed of the document 200 is changed by changing the gear.

[0015] Meanwhile, the upstream transport rollers 203, the intermediate rollers 204, and the intermediate rollers 205 are wound around each of their respective rotation shafts by a single belt 206. The drive of the drive motor 211 is transmitted to the belt 206 by the rotation of the intermediate rollers 205. Therefore, the upstream transport rollers 203, the intermediate rollers 204, and the intermediate rollers 205 can be rotated synchronously at the same speed. Here, the upstream transport rollers 203, the intermediate rollers 204, and the intermediate rollers 205 transport the original 200 at the same transport speed. Meanwhile, the downstream transport rollers 210 transport the original 200 faster than the intermediate rollers 204 and the intermediate rollers 205. When the original 200 is transported by the upstream transport rollers 203 and the downstream transport rollers 210, the original 200 is transported at a stable transport speed by the tension of the downstream transport rollers 210.

[0016] Next, the arrangement of the intermediate roller 205 and the intermediate roller 204 relative to the line sensor unit 207 will be further described. At the upstream reading position, the line sensor unit 207-2 is arranged between the intermediate roller 204-2 and the intermediate roller 204-1. In addition, in the transport direction, the intermediate roller 204-2 and the intermediate roller 204-1 are arranged at a position overlapping with the line sensor unit 207-2. Meanwhile, the intermediate roller 205 is arranged between the line sensor unit 207-1 and the line sensor unit 207-3. In addition, in the transport direction, the intermediate roller 205 is arranged at a position overlapping with the line sensor unit 207-1 and the line sensor unit 207-3. In addition, in the transport direction, the line sensor unit 207-3 is arranged between the intermediate roller 204-2 and the downstream transport roller 210, and the line sensor unit 207-1 is arranged between the intermediate roller 204-1 and the downstream transport roller 210. On the other hand, line sensor unit 207-2 is disposed between upstream conveying roller 203 and intermediate roller 205. Also, in the main scanning direction, the width of the intermediate roller is shorter than the width of each line sensor unit 207. At the upstream reading position, the intermediate rollers and line sensor units alternate in this order as the reader proceeds in the x direction. On the other hand, at the downstream reading position, the line sensor units and intermediate rollers alternate in this order as the reader proceeds in the x direction. This order can be applied to cases where there are more than three or an even number of lines. The relationship between the line sensor units and intermediate rollers on the upstream and downstream sides may be interchanged.

[0017] The reading surface of the line sensor unit 207 faces the glass plate 208, and the focal position of reading is the contact surface between the original 200 and the glass plate 208. The pressing plate 209 presses the passing original 200 against the glass plate 208 with a predetermined pressure in a pressing area. The intermediate roller 205 also plays a role in discharging the original 200 that has passed through the pressing area on the upstream side to a reading position on the downstream side.

[0018] The clamping position of the intermediate roller 204-2 and the intermediate roller 204-1 is on the upstream side with respect to the reading position of the line sensor unit 207-2. Also, the clamping position of the intermediate roller 205 is on the upstream side with respect to the reading position of the line sensor unit 207-3 and the line sensor unit 207-1. That is, at each of the reading positions on the upstream side and the downstream side, the line sensor unit 207 is disposed downstream (in the +y-axis direction) from the roller. This is because if the reading position of the line sensor unit 207 is disposed upstream from each roller, tension may not be applied to the original 200. Note that the difference (DA) between the reading positions of the line sensor units corresponding to the clamping positions of the intermediate rollers is set to be equal to or smaller than the margin area at the rear end of the original 200 in the conveying direction. That is, after the image is read at the reading position, the original 200 passes through the intermediate rollers. As a result, the influence on the image data is reduced.

[0019] FIG. 3 is a block diagram showing a hardware configuration of the scanner 100. The control unit 400 controls the reading of an image by the reading unit and the transport of the document 200 on the transport path. The control unit 400 includes a CPU 401, a memory 402, a motor control circuit 403, an interface (hereinafter, IF) unit 404, a bus 409, a power supply unit 405, and an A / D conversion unit 406. The operation unit / display unit 103 is connected to the CPU 401 and is a touch panel with an LCD composed of an operation unit 407 and a display unit 408. The LCD of the display unit 408 displays information on the document 200 from which an image is to be read and information on the settings of the device according to an instruction from the CPU 401. In addition, the user can input to the scanner 100, for example, change the reading format and the settings of the device, by operating the touch panel of the operation unit 407 while checking the information displayed on the LCD of the display unit 408.

[0020] The drive motor 211 is driven by the CPU 401 via a motor control circuit 403. Each roller, such as the upstream transport roller 203, the intermediate roller 204, the intermediate roller 205, and the downstream transport roller 210, rotates when driven by the drive motor 211. The outputs of the document detection sensor 201 and the edge detection sensor 202 are input to the CPU 401. The CPU 401 executes the reading operation of the multiple line sensor units 207 (1 to 3) and the transport operation of the document 200 based on the changes in the output signals of these sensors and the state of the drive motor 211.

[0021] The multiple line sensor units 207 (1 to 3) output the read images as analog signals to the control unit 400. The analog signals output from the multiple line sensor units 207 (1 to 3) are converted into digital signals by the respective A / D conversion units 406 and input to the CPU 401. The CPU 401 processes the data converted into digital signals by the respective A / D conversion units 406, splices the images together, and can transmit the spliced ​​data as image data to an external device connected by USB or LAN via the IF unit 404. The power supply unit 405 generates a voltage required for each unit and supplies power. The memory 402 can store multiple lines of image data. The line sensor units acquire three-color images, but may also acquire black and white images.

[0022] (Document transport status) 4A and 4B are diagrams showing the transport state of the original. In Fig. 4A, when a user inserts an original 200 from the supply port 101, an original detection sensor 201 detects the original 200. When the original 200 is detected, a drive motor 211 rotates and transmits a driving force to a belt 212. As a result, the upstream transport rollers 203, the downstream transport rollers 210, the intermediate rollers 205, and the intermediate rollers 204 rotate. Here, the downstream transport rollers 210 are rotated so as to have a transport speed faster than that of the intermediate rollers 205, and tension is applied to the original 200.

[0023] In FIG. 4B, the leading edge of the document 200, which is drawn into the housing by the rotation of the upstream transport rollers 203, is detected by the edge detection sensor 202. When the leading edge of the document is detected by the edge detection sensor 202, the control unit 400 calculates the timing to start reading. After that, the document 200 is transported downstream by the intermediate rollers 204 and 205 in sequence. Meanwhile, when the timing to start reading is reached, the line sensor unit 207 starts reading the image of the document 200. In FIG. 4C, the leading edge of the document 200 reaches the downstream transport rollers 210. At this time, the document 200 is read by the multiple line sensor units 207 (1 to 3) while being transported by each roller. In addition, the downstream transport rollers 210 rotate so as to have a transport speed higher than the intermediate rollers 205 and the upstream transport rollers 203. The difference in transport speed applies tension to the document 200. As a result, the posture of the document 200 during transport is stable.

[0024] In Fig. 4(d), when the rear end of the original 200 passes the upstream transport rollers 203, the rear end of the original is detected by the edge detection sensor 202. When the rear end of the original is detected by the edge detection sensor 202, the control unit 400 calculates the reading end timing. In Fig. 4(e), when the original 200 passes the intermediate rollers 205, the reading of the image by the line sensor unit 207 ends at the reading end timing. Thereafter, the original 200 is discharged from the discharge port by the downstream transport rollers 210. During this time, the downstream transport rollers 210 rotate so as to have a faster transport speed than the intermediate rollers 205 and the upstream transport rollers 203, as described above.

[0025] (flowchart) Figures 5 and 6 are flow charts showing the image reading sequence for reading an image. Figure 5 shows the sequence up to the start of image reading, and Figure 6 shows the sequence after the start of image reading. The sequences in Figures 5 and 6 are executed consecutively.

[0026] In step S501, control unit 400 periodically executes the detection operation of document 200 by document detection sensor 201. When a user inserts document 200, document detection sensor 201 detects document 200 (FIG. 4(a)). If document 200 is detected by document detection sensor 201, the process proceeds to S502.

[0027] In step S502, the control unit 400 starts rotating the drive motor 211. When the drive motor 211 starts rotating, the upstream transport rollers 203, the intermediate rollers 204, the intermediate rollers 205, and the downstream transport rollers 210 start rotating by the belts 212 and 206, respectively. The document 200 is pulled from the supply table 102 into the inside of the transport path by the upstream transport rollers 203 (FIG. 4(b)). At this time, the transport speed of the document 200 by the downstream transport rollers 210 is higher than the transport speed by the upstream transport rollers 203, the intermediate rollers 204, and 205.

[0028] In step S503, control unit 400 periodically executes an operation of detecting the edge of the document by edge detection sensor 202. When the leading edge of document 200 drawn into the inside of the conveying path reaches a predetermined position, edge detection sensor 202 detects the leading edge of document 200. When the leading edge of document 200 is detected, the process proceeds to S504.

[0029] In step S504, control unit 400 determines the timing to start reading the image of original 200. The reading start timing is calculated using the conveying speed of upstream conveying rollers 203 and the distance from edge detection sensor 203 to the upstream reading position. After the reading start timing is determined, original 200 passes between glass plate 208 and pressing plate 209.

[0030] In step S505, when the reading start timing arrives, the control unit 400 starts reading the original document using the line sensor unit 207. In parallel with this, the original document 200 is transported in sequence by the intermediate rollers 204 and 205. Then, in FIG. 4(c), the leading edge of the original document 200 reaches the downstream transport rollers 210. At this time, the downstream transport rollers 210 are rotating so as to have a transport speed higher than the intermediate rollers 205 and the upstream transport rollers 203. Due to the difference in transport speed, tension is applied to the original document 200, and the posture of the original document 200 during transport becomes more stable. After this, the control unit 400 continues the operation of reading the original document 200 using the multiple line sensor units 207(1-3) and the operation of transporting the original document in the transport path.

[0031] In step S601, the control unit 400 periodically executes the detection operation of the original 200 by the edge detection sensor 202 (FIG. 4(d)). If the edge detection sensor 202 detects the original 200, the control unit 400 determines that the rear edge of the original 200 has not yet arrived. On the other hand, if the edge detection sensor 200 no longer detects the original, the control unit 400 determines that the rear edge has arrived.

[0032] In step S602, when the rear end of the document 200 is detected, the control unit 400 determines the timing to end reading of the image. The timing to end reading is calculated using the conveying speed of the intermediate rollers 205 and the distance from the edge detection sensor 203 to the downstream reading position.

[0033] In step S603, when the timing for ending reading arrives, the control unit 400 ends image reading by the multiple line sensor units 207 (1-3) (FIG. 4(e)). When image reading ends, image stitching is performed. When the original 200 passes through the intermediate rollers 205, the state in which tension is applied to the original 200 ends. Thereafter, the original 200 is transported by the downstream transport rollers 210 and discharged from the rear side of the scanner 100.

[0034] In step S604, the control unit 400 stops driving the drive motor 211. After that, the control unit 400 ends the reading operation and the transport operation of the original 200.

[0035] With the above configuration, even after the rear end of the document 200 has passed the upstream transport rollers 203, tension can be maintained on the document 200 by the intermediate rollers 205 and the downstream transport rollers 210. As a result, degradation in the image quality of the read image can be suppressed.

[0036] <Second Example> The second embodiment is a sheet-fed type image reading apparatus configured with a plurality of line sensor units arranged in a staggered manner, similar to the first embodiment. Here, differences from the first embodiment will be particularly described.

[0037] The arrangement of each roller and each line sensor unit 207 (1-3) is the same as in the first embodiment. The upstream transport roller 203 and the intermediate roller 204 are rotated so that the transport speed of the original 200 is the same transport speed. On the other hand, the intermediate roller 205 is rotated so that the transport speed of the original 200 is faster than that of the upstream transport roller 203. Furthermore, the downstream transport roller 210 is rotated so that the transport speed of the original 200 is faster than that of the intermediate roller 205. The difference in transport speed is appropriately adjusted by the gear diameter or roller diameter. Note that a configuration in which the driving motor is divided for each roller may be used. As a result, the transport speed of the original 200 increases in the order of the downstream transport roller 210, the intermediate roller 205, and the upstream transport roller 203. Note that both the first embodiment and the second embodiment may be selected. In this case, the transport speed by the intermediate roller 205 is equal to or faster than the transport speed by the upstream transport roller 203.

[0038] In this way, a difference in conveying speed can be created and tension can be maintained even between the intermediate roller 205 and the upstream conveying roller 203. Even if the leading edge of the document 200 has not yet passed the downstream conveying roller 210, the area of ​​the leading edge of the document 200 that is not subjected to tension during the reading operation can be made smaller. [Explanation of symbols]

[0039] 207 Line sensor unit 203 Upstream transport roller 204 Intermediate Roller 205 Intermediate Roller 210 Downstream conveying roller

Claims

1. a first conveying roller for conveying the document in a conveying direction; a first sensor unit disposed downstream of the first transport roller in the transport direction and configured to read a document; a second sensor unit disposed downstream of the first sensor unit and configured to read a document; a second transport roller disposed downstream of the second sensor unit in the transport direction and configured to transport a document, an intermediate roller disposed between the first transport roller and the second transport roller in the transport direction and configured to transport the document; an image reading device, characterized in that a conveying speed by the second conveying roller is faster than a conveying speed by the first conveying roller, and a conveying speed by the intermediate roller is faster than or equal to the conveying speed by the first conveying roller and slower than the conveying speed by the second conveying roller.

2. 2. The image reading device according to claim 1, wherein the intermediate roller is disposed at a position overlapping with the second sensor unit in the transport direction.

3. 3. The image reading apparatus according to claim 2, wherein the intermediate roller and the first transport roller have the same transport speed.

4. 3. The image reading apparatus according to claim 2, wherein a conveying speed of the intermediate roller is higher than a conveying speed of the first conveying roller and lower than a conveying speed of the second conveying roller.

5. 3. The image reading apparatus according to claim 2, wherein a nipping position where the intermediate rollers nip the document in the transport direction is upstream of a reading position by the second sensor unit.

6. 6. The image reading device according to claim 5, wherein a distance between the clamping position and the reading position in the transport direction is equal to or smaller than a margin area at a rear end of the document.

7. 3. The image reading apparatus according to claim 2, wherein a plurality of the second sensor units are arranged in a width direction of the document, and the intermediate roller is arranged between the second sensor units.

8. 3. The image reading apparatus according to claim 2, further comprising a second intermediate roller that is disposed at a position overlapping with the first sensor unit in the transport direction and transports the document.

9. 9. The image reading apparatus according to claim 8, wherein a plurality of the second intermediate rollers are arranged in a width direction of the document, and the second sensor unit is arranged between the second intermediate rollers.

10. a first belt that is wound around the second conveying roller and the intermediate roller; 4. The image reading apparatus according to claim 3, further comprising: a drive motor for driving the first belt.

11. 11. The image reading apparatus according to claim 10, further comprising an applying mechanism for applying tension to the first belt.

12. 4. The image reading apparatus according to claim 3, further comprising a second belt that is wound around the first transport roller and the intermediate roller.

13. 2. The image reading device according to claim 1, wherein the intermediate roller is disposed at a position overlapping with the first sensor unit in the transport direction.

14. An image reading device according to any one of claims 1 to 13, a recording unit that records the image read by the image reading device on a recording medium.

Images