JP7165231B2 - Image reader - Google Patents

Description

The present invention relates to an image reading apparatus having a reading section that reads an image of a document being conveyed by a conveying section.

Japanese Unexamined Patent Application Publication No. 2002-200003 describes an example of an image reading apparatus that conveys a document set on a setting section to a predetermined reading position and reads an image of the document conveyed to the reading position by a reading section.

By the way, when a color document is transported, a transport failure such as a paper jam is more likely to occur than when a monochrome document is transported. Therefore, in the image reading apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200003, when reading the image of a color document, the document is conveyed at a lower speed than when reading the image of a monochrome document. Specifically, when information is input based on a user's operation, the controller of the image reading apparatus determines whether to read a color document image or a monochrome document image. Then, the normal transport mode is selected when reading an image of a monochrome document, and the transport mode for lower-speed transport than the normal transport mode is selected when reading an image of a color document. The transport section is operated in the transport mode selected in this way.

JP 2003-128298 A

By the way, an image reading apparatus may read images of various documents having different thicknesses. When transporting thin documents, transport failures such as paper jams are more likely to occur than when transporting thick documents. Therefore, when reading an image of a thin document, it is desirable to convey the document at a lower speed than when reading an image of a thick document.

However, in an image reading apparatus that causes a reading section to read an image of a document being conveyed by a conveying section, there is generally a correlation between the conveyance speed of the document and the resolution of the acquired image. Specifically, image data, which is data of an image with higher resolution, is generated as the document transport speed is lower. Therefore, when the document transport speed is changed according to the thickness of the document, the generated image data is not limited to image data having a resolution desired by the user.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus capable of generating image data having a resolution desired by a user even when the document transport speed is variable.

An image reading apparatus for achieving the above object comprises a conveying section that conveys a document, a reading section that reads an image of the document conveyed by the conveying section, and image data that is data of an image read by the reading section. and a control unit that generates a specific An operation of reading an image from a document when setting information is not input to the control unit is set as a first reading mode, and an operation of reading an image from the document when the specific setting information is input to the control unit. is set as the second reading mode, the control section causes the reading section to read an image from a document conveyed by the conveying section at a speed corresponding to the requested resolution in the first reading mode. and generate image data of an image read by the reading unit, and in the second reading mode, the image is read from the document conveyed by the conveying unit at a lower speed than in the first reading mode. By delaying the timing compared to the case of the first reading mode while causing the unit to read the image, the image data of the image having the same resolution as that of the case of the first reading mode is generated. Under the condition that the second reading mode is selected, the control unit changes the reading mode to be executed from the second reading mode to the first reading mode when starting to read an image based on the next job. Switch to read mode.

According to the above configuration, when image reading is instructed in a situation where the specific setting information is not input to the control section, the first reading mode is performed. That is, when the user recognizes that the document is not thin, the user instructs the image reading apparatus to read the image without performing a user operation such as inputting the specific setting information to the control unit. be done. At this time, the resolution of the image based on the generated image data can be selected by the user when the user inputs the reading instruction. Therefore, the document is conveyed at a conveying speed correlated with the resolution requested by the user, and image data of the resolution requested by the user is generated. Therefore, it is possible to provide the user with image data having a resolution desired by the user.

On the other hand, when image reading is instructed under the condition that the specific setting information is input to the control section, the second reading mode is executed. That is, when the user recognizes that the document is thin, the user instructs the image reading device to read the image after performing the user operation to input the specific setting information to the control unit. be done. At this time, although the document is conveyed at a lower speed than in the case of the first reading mode, image data of an image having the same resolution as in the case of the first reading mode is generated. That is, it is possible to provide the user with image data that does not depend on the transport speed of the document while suppressing transport failures such as paper jams. Therefore, even if the document transport speed is variable, it is possible to generate image data having a resolution desired by the user.

In the image reading apparatus, the control unit inputs the specific setting information while the conveying unit is conveying one of the originals when continuously reading images of a plurality of originals. In this case, it is preferable to switch the reading mode to be performed from the first reading mode to the second reading mode at the start of reading the image of the document next to the one document.

According to the above configuration, when the images of a plurality of originals are read continuously, if the specific setting information is input to the control unit while one of the originals is being conveyed, the one original is read. The first reading mode is continued until the reading of the image is completed. That is, while one document is being transported, the reading mode is not changed, and the transport speed of the same document is not changed. Therefore, it is possible to suppress an increase in the control load due to the switching of the reading mode during image reading.

After that, when reading the image of the next document, the second reading mode is executed instead of the first reading mode. That is, when reading the images of the first and subsequent documents, the documents are conveyed at a low speed. Moreover, since it is the second reading mode, even if the document is conveyed at a low speed, image data, which is image data with the same resolution as in the case of the first reading mode, is generated. Therefore, at the time of reading the images of the originals after the first original, the originals are conveyed at a low speed, thereby suppressing the occurrence of conveyance failures of the same originals and providing the user with image data that does not depend on the conveying speed. becomes possible.

Further, an image reading apparatus for achieving the above object comprises a conveying section for conveying a document, a reading section for reading an image of the document conveyed by the conveying section, and an image read by the reading section. and a control unit for generating data, wherein an operation of reading an image from a document conveyed by the conveying unit when the document is not thin is set as a first reading mode, and the conveying unit When the operation of reading an image from a thin document conveyed by the unit is set to the second reading mode, the control unit sets the resolution to the requested resolution in the first reading mode. causing the reading unit to read an image from a document conveyed by the conveying unit at a corresponding speed, generating image data of the image read by the reading unit, and generating image data of the image read by the reading unit; While causing the reading section to read an image from a document conveyed by the conveying section at a lower speed than in the mode, image data of an image having the same resolution as in the first reading mode is generated. Note that "when the document is not thin" means that the document is not thinner than the specified thickness, and "when the document is thin" means that the document is thicker than the specified thickness. is thin.

According to the above configuration, the first reading mode is performed when the document conveyed by the conveying section is not thin. When the user instructs the image reading apparatus to read the image of the document, the user can select the resolution of the image based on the generated image data. Therefore, it is possible to provide the user with image data having a resolution desired by the user.

On the other hand, when the document conveyed by the conveying section is thin, the second reading mode is performed. In this case, although the document is conveyed at a lower speed than in the first reading mode, image data having the same resolution as in the first reading mode is generated. That is, it is possible to provide the user with image data that does not depend on the transport speed of the document while suppressing transport failures such as paper jams. Therefore, even if the document transport speed is variable, it is possible to generate image data having a resolution desired by the user.

The image reading apparatus includes a sound wave sensor that outputs sound waves to a document being transported by the transport section and detects an attenuation rate of the sound waves. When the attenuation rate of the sound wave detected by the sound wave sensor is less than the determination attenuation rate under the condition that the document is being conveyed, it is determined that the thickness of the document being transported by the transport unit is thin, and the second reading mode is performed. is preferred.

The thinner the document, the smaller the attenuation rate of the sound waves detected by the sound wave sensor. Therefore, in the above configuration, when the attenuation rate of the sound wave detected by the sound wave sensor is less than the determination attenuation rate, it can be determined that the thickness of the document being conveyed is thin, so the second reading mode is performed. I'm trying By using the detection result of the sound wave sensor in this way, the second reading mode can be automatically selected and executed.

In the above image reading device, the sound wave sensor is a sensor for detecting whether or not a plurality of documents are being conveyed while overlapping each other, and is used to determine whether or not a plurality of documents are being conveyed while being overlapped. A multiple feeding detection attenuation rate larger than the determination attenuation rate is provided as a threshold value of the above, and the control section controls the attenuation rate of the sound wave detected by the sound wave sensor under the condition that the document is being conveyed by the conveying section. When the attenuation rate is equal to or more than the determination attenuation rate and less than the double feed detection attenuation rate, the first reading mode is performed, and the sound wave detected by the sound wave sensor under the condition that the document is conveyed by the conveying section. is equal to or higher than the multi-feeding detection attenuation rate, it is preferable to stop the document transport by the transport section and the image reading by the reading section.

When a plurality of documents are conveyed while being overlapped, the attenuation rate of sound waves detected by the sound wave sensor tends to be greater than when only one document is conveyed. Further, the attenuation rate of sound waves when two documents with thin thickness are overlapped becomes larger than the attenuation rate of sound waves when one document is conveyed which is not thin. Therefore, according to the above configuration, the multi-feeding detection attenuation rate, which is the threshold value for determining whether or not a plurality of documents are being conveyed in an overlapping state, is set to a value larger than the determination attenuation rate. By using this multi-feeding detection attenuation factor, it is possible to determine whether a single not-thin original is being conveyed, or whether a plurality of originals are being conveyed in an overlapping state. By employing such determination results, it is possible to appropriately drive the image reading apparatus according to the situation.

In the above image reading device, the conveying unit includes a pair of conveying rollers located upstream in the document conveying direction from the reading unit, and a pair of conveying rollers arranged upstream in the conveying direction of the document from the pair of conveying rollers. and a feed roller for feeding toward the roller pair, and the sound wave sensor is preferably arranged between the feed roller and the transport roller pair in the transport direction of the document.

According to the above configuration, it is possible to determine whether or not the document being transported is thin on the upstream side in the transport direction of the reading unit.
In the above image reading apparatus, the control unit changes the reading mode to be performed from the second reading mode to the first reading mode when a predetermined end condition is satisfied under the condition that the second reading mode is selected. It is preferable to switch to the reading mode of

According to the above configuration, the mode can be switched from the second reading mode to the first reading mode when the execution of the second reading mode becomes unnecessary.
In the image reading apparatus, when the setting information for ending the second reading mode is input under the condition that the second reading mode is selected, the control unit reads the next image. It is preferable to switch the reading mode to be executed from the second reading mode to the first reading mode.

According to the above configuration, when the setting information indicating that the execution of the second reading mode is unnecessary is input, the first reading mode can be executed when reading the next image.
In the image reading apparatus, the control unit selects the reading mode to be executed when starting reading an image based on the next job under the condition that the second reading mode is selected. It is preferable to switch from the reading mode to the first reading mode.

According to the above configuration, the first reading mode can be automatically performed when reading an image based on the next job.

1 is a perspective view showing a schematic configuration of an image reading apparatus according to a first embodiment; FIG. FIG. 2 is a side view showing a conveying device and its peripheral members of the image reading apparatus; A table for explaining a plurality of first reading modes. FIG. 2 is a block diagram for explaining the functional configuration of the image reading apparatus; 4 is a flowchart for explaining a processing procedure when reading an image with the image reading apparatus; 10 is a flowchart for explaining a processing procedure when reading an image with the image reading apparatus according to the second embodiment; FIG. 11 is a block diagram for explaining the functional configuration of an image reading apparatus according to a third embodiment; FIG. 4 is a flowchart for explaining a processing procedure when reading an image with the image reading apparatus;

(First embodiment)
A first embodiment embodying an image reading apparatus will be described below with reference to FIGS. 1 to 5. FIG.
As shown in FIG. 1, the image reading apparatus 11 of this embodiment includes a housing 12 and a cover member 13 rotatably supported by the housing 12 . The cover member 13 is provided with a user interface 50 of the device. That is, the user interface 50 has multiple buttons 51 and multiple lamps 52 .

One of the buttons 51 is a specifying button 51A that is operated when instructing to read an image in a second reading mode, which will be described later. One of the lamps 52 is a specification lamp 52A that is lit when the specification button 51A is in the ON state. Note that the identification lamp 52A is extinguished when the identification button 51A is in the OFF state.

Further, as shown in FIG. 2, the image reading device 11 is provided with a setting section 14 in which a document MS whose image has not yet been read is set. When a plurality of manuscripts MS are set on the setting section 14 , the manuscripts MS are stacked on the set section 14 . Further, inside the housing 12, a transporting device 20 as a transporting unit that transports the document MS and a reading device 30 that reads an image of the document MS transported by the transporting device 20 are provided. Then, the originals MS set in the setting section 14 enter the housing 12 one by one and are conveyed along a predetermined conveying path. The image of the document MS is read while being conveyed, and the document MS whose image has been read is discharged from the housing 12 .

As shown in FIG. 2, the transport device 20 includes a feed roller 21, a feed roller pair 22, a transport roller pair 23, and a discharge roller pair 24, which are arranged in order from upstream to downstream in the document MS transport direction. there is Further, the transport device 20 includes a feed motor 25 and a transport motor 26 as drive sources for transporting the document MS. The drive force from the feed motor 25 is transmitted to the feed roller 21 , and the drive force from the transport motor 26 is transmitted to the feed roller pair 22 , the transport roller pair 23 and the discharge roller pair 24 .

The feeding roller 21 feeds the lowest document MS among the plurality of documents MS set in the setting section 14 into the housing 12 . A guide member 27 is arranged above the feed roller 21 . This guide member 27 restricts the entry of documents other than the lowest document MS into the housing 12 .

The feed roller pair 22 has a drive roller 221 drivingly connected to the transport motor 26 and a driven roller 222 to which driving force from the transport motor 26 is transmitted through the drive roller 221 . As the driving roller 221 and the driven roller 222 rotate, the document MS is nipped between the two rollers 221 and 222 and sent out toward the transport roller pair 23 .

The driven roller 222 of the feed roller pair 22 is a retard roller to which a constant rotational load is applied by a torque limiting mechanism such as a torque limiter. Therefore, when a plurality of manuscripts MS are fed into the housing 12 from the setting section 14 in a state of being overlapped, only one manuscript MS is fed downstream in the transport direction by the feed roller pair 22 . In this respect, the two rollers 221 and 222 that constitute the feed roller pair 22 function as “feed rollers” that feed the document MS toward the transport roller pair 23 .

The transport roller pair 23 is arranged upstream of the reading device 30 in the transport direction, which is on the right side in the drawing. The conveying roller pair 23 has a driving roller 231 drivingly connected to the conveying motor 26 and a driven roller 232 to which the driving force from the conveying motor 26 is transmitted through the driving roller 231 . As the drive roller 231 and the driven roller 232 rotate, the document MS is nipped between the two rollers 231 and 232 and conveyed toward the reading device 30 .

The discharge roller pair 24 is arranged downstream of the reading device 30 in the transport direction, which is the left side in the drawing. The discharge roller pair 24 has a drive roller 241 drivingly connected to the transport motor 26 and a driven roller 242 to which driving force from the transport motor 26 is transmitted through the drive roller 241 . As the driving roller 241 and the driven roller 242 rotate, the document MS is nipped between the two rollers 241 and 242 and discharged out of the housing 12 .

The reading device 30 has two reading units 31 and 32 arranged on both upper and lower sides of the document MS conveyed along the conveying path. Among the reading units 31 and 32 , the lower reading unit is the first reading unit 31 , and the upper reading unit is the second reading unit 32 . That is, the first reading section 31 reads an image on one side (lower side in the drawing) of the manuscript MS, and the second reading section 32 reads an image on the other side (upper side in the drawing) of the manuscript MS. As the reading unit, for example, a contact image sensor module (CISM) can be cited. Of course, modules other than the CISM may be employed as the reader.

Note that, as shown in FIG. 2, an edge detection sensor 600 that detects the edge of the document MS is provided between the reading device 30 and the pair of transport rollers 23 in the transport direction of the document MS.
In addition, a multifeed detection sensor 610 is provided between the feed roller pair 22 and the transport roller pair 23 in the transport direction of the documents MS for detecting that a plurality of documents MS are transported in an overlapping state. ing. The double feed detection sensor 610 is a sound wave sensor and has an output section 611 that outputs sound waves and an input section 612 that receives the sound waves output from the output section 611 . One of the output unit 611 and the input unit 612 is arranged above the document MS transported along the transport path in the figure, and the output unit 611 and the input unit 612 are arranged below the document MS transported along the transport path in the figure. The other of the section 611 and the input section 612 is arranged. In the example shown in FIG. 2, an input section 612 is arranged on the upper side of the drawing, and an output section 611 is arranged on the lower side of the drawing.

Then, the double feed detection sensor 610 detects the attenuation rate α of the sound waves. When the output value of the sound wave output from the output unit 611 is "X1" and the input value of the sound wave input to the input unit 612 is "X2", the attenuation factor α is expressed by the following relational expression (Equation 1) is a value that can be calculated using

α = (X1-X2)/X1 (Formula 1)
By the way, in the image reading device 11 of this embodiment, the user can select the resolution of the image based on the image data output from the device. That is, the first reading mode, which is an example of an image reading mode, can be selected by the user's operation of the user interface 50 or the user's operation of an external device communicating with the image reading apparatus 11 .

Further, in the image reading device 11 that reads the image of the document MS being conveyed by the reading units 31 and 32, the lower the conveying speed of the document MS, the higher the resolution of the image data generated. be. Therefore, it can be said that the first reading mode for providing high-resolution image data to the user is a mode in which the document MS is conveyed at a speed correlated with the resolution requested by the user.

FIG. 3 shows an example of a table showing a plurality of (three in this case) first reading modes. As shown in FIG. 3, the first mode is a reading mode in which the document MS is transported at a high speed and low-resolution image data is generated. The second mode is a reading mode in which the document MS is transported at a medium speed and image data with a medium resolution is generated. The third mode is a reading mode in which the transport speed of the document MS is low and high-resolution image data is generated.

When the user instructs the image reading device 11 to read an image, the user can select one reading mode (that is, the first reading mode) from among the above three modes.

Here, with the image reading device 11 of the present embodiment, it is possible to read images of various manuscripts MS having different thicknesses. Further, the thinner the document MS, the more likely it is that a transport failure such as a paper jam will occur during transport. In order to suppress the occurrence of such transport failures, it is desirable to transport the document MS at a low speed.

Therefore, as described above, the user interface 50 is provided with the specifying button 51A. This specifying button 51A is a button that is turned on when reading an image of a document MS that is likely to cause a transport failure during transport, such as a thin document MS. Then, when the specification button 51A is turned on by the user's operation, specific setting information, which is information relating to a specific user operation, is input to the control device 60 (see FIG. 4) as a control section of the image reading device 11. and a second reading mode different from the first reading mode is implemented. The "specific user operation" referred to here is a button operation by the user for turning on the specification button 51A.

That is, the operation of reading an image from the document MS when specific setting information is not input to the control device 60 is set as the first reading mode. Further, the operation of reading an image from the document MS when specific setting information is input to the control device 60 is set as the second reading mode.

The second reading mode is a mode for generating image data with the same resolution as in the first reading mode while conveying the document MS at a lower speed than in the first reading mode. For example, when the user selects to implement the first mode, that is, when the resolution requested by the user is low, and the specifying button 51A is turned on, the following second mode read mode is implemented.
- The document MS is conveyed at a lower speed than when the first mode is carried out. For example, it is transported at the transport speed of the document MS in the third mode or at a speed corresponding to the same transport speed.
• Generate image data with the same resolution as in the first mode.

Further, when the specifying button 51A is turned on under the condition that the user has selected the third mode, that is, under the condition that the resolution requested by the user is high, the following second read mode is implemented.
- The document MS is conveyed at a lower speed than when the third mode is executed.
• Generate image data with the same resolution as in the third mode.

Since the document MS is conveyed at a low speed by executing the second reading mode, the occurrence of conveyance failure of the thin document MS is suppressed even when the image of the thin document MS is read. be. Moreover, even if the document MS is conveyed at such a low speed, the resolution of the image based on the generated image data is the resolution requested by the user, that is, in the first reading mode selected by the user. have the same resolution.

Next, the control device 60 of the image reading device 11 will be described with reference to FIG.
The control device 60 includes a microcomputer including a CPU, ROM, RAM, etc., and various driver circuits. As shown in FIG. 4, the control device 60 includes a transport control section 61, a mode selection section 66, a data generation section 64, and a data output section 65 as functional sections configured by at least one of software and hardware. I'm in.

The transport controller 61 controls the transport device 20 . That is, when an instruction to start transporting the document MS, that is, an instruction to read the image of the document MS is input, the transport control unit 61 drives the delivery motor 25 to rotate the feed roller 21 . As a result, one document MS is sent into the housing 12 from the setting section 14 . Then, when the document MS conveyed by the rotation of the feed roller 21 is nipped by the two rollers 221 and 222 forming the feed roller pair 22, the transport control unit 61 stops driving the feed motor 25. .

Further, the transport control unit 61 rotates the rollers 221 , 231 , 241 , 222 , 232 , and 242 of the feed roller pair 22 , the transport roller pair 23 and the discharge roller pair 24 by driving the transport motor 26 . The start timing of the transport motor 26 may be the same as the start timing of the delivery motor 25 or may be later than the start timing of the delivery motor 25 . Then, the transport control unit 61 stops driving the transport motor 26 after the timing at which the trailing edge of the document MS passes the discharge roller pair 24 .

Information about the transport speed of the document MS is input from the mode selection unit 66 to the transport control unit 61 . Then, the transport control unit 61 controls driving of the transport motor 26 so as to transport the document MS at a speed based on the input information.

The mode selection unit 66 determines the reading mode to be performed based on the user information input when reading the image. That is, when information for specifying the image resolution is input from the user interface 50 or an external device, the mode selection unit 66 selects the first reading mode according to the image resolution requested by the user. (see Figure 3). For example, when the user requests a high-resolution image, the mode selector 66 selects the third mode. The mode selection unit 66 then outputs information about the selected reading mode to the transport control unit 61 and the data generation unit 64 . Also, the mode selection unit 66 selects the second reading mode when the specification button 51</b>A is on, and outputs information about the second reading mode to the transport control unit 61 and the data generation unit 64 .

The data generation unit 64 controls the reading units 31 and 32 of the reading device 30 and acquires the images read by the reading units 31 and 32 . Then, the data generating section 64 generates image data that is the data of the images read by the reading sections 31 and 32 and outputs this image data to the data output section 65 .

The resolution of the image based on the image data generated at this time is the resolution according to the information about resolution input from the mode selection unit 66 . That is, when the specifying button 51A is in the OFF state, the data generation unit 64 generates image data having a resolution corresponding to the transport speed of the document MS. On the other hand, when the specification button 51A is in the ON state, the data generation unit 64 generates image data with the resolution requested by the user even if the transport speed of the document MS is low.

Acquisition of an image from the document MS is realized by causing the reading units 31 and 32 to read the image at predetermined timings while the document MS is being conveyed. Therefore, the resolution of the images acquired by the reading units 31 and 32 increases as the conveying speed of the document MS decreases. Therefore, the resolution of the image acquired when the second reading mode is performed may be higher than the resolution desired by the user. Therefore, in the second reading mode, the data generator 64 lowers the resolution of the acquired image to the resolution desired by the user, and generates image data with the same resolution.

Further, when the second reading mode is performed, the data generation unit 64 controls the reading unit 31 so that an image with a low resolution (that is, an image with the resolution when it is assumed that the first reading mode is performed) can be obtained. , 32 may be controlled. For example, by delaying the predetermined timing, it is possible to acquire an image with a resolution lower than the resolution corresponding to the conveying speed of the document MS. In this case, the data generation unit 64 can generate image data with the resolution requested by the user even if the transport speed of the document MS is low. In other words, it is not necessary to perform processing for lowering the resolution of the acquired image.

The data output unit 65 transmits the image data generated by the data generation unit 64 to the external device.
Next, with reference to the flowchart shown in FIG. 5, the processing procedure for reading the image of the document MS will be described.

As shown in FIG. 5, it is determined whether or not the specification button 51A is in the ON state under the condition that any one of the first mode, the second mode and the third mode is selected. (step S11). If the specifying button 51A is in the OFF state (step S11: NO), the first reading mode is selected (step S12), and the process proceeds to step S14, which will be described later. On the other hand, if the specification button 51A is on (step S11: YES), the second reading mode is selected (step S13), the specification lamp 52A is turned on, and the process proceeds to the next step S14. be.

In step S14, image reading is started by starting the selected reading mode. For example, when the specification button 51A is in the OFF state and the second mode is selected, the document MS is conveyed at a medium speed by the conveying device 20, and image data of medium resolution is generated. When the specifying button 51A is on and the second mode is selected, the document MS is transported at a low speed by the transporting device 20, and image data of an image with medium resolution is generated.

While the image is being read in this way, it is determined whether or not the attenuation rate α detected by the double feed detection sensor 610 is equal to or greater than the double feed detection attenuation rate αTh1 (step S15). . The multi-feeding detection attenuation rate αTh1 is a threshold value for determining whether or not a plurality of originals MS are being conveyed in an overlapping state. For example, when only one original document MS of normal thickness is conveyed and this original document MS is positioned between the output section 611 and the input section 612 of the multi-feeding detection sensor 610, the attenuation factor α is defined as "standard attenuation rate”. In this case, the double feed detection attenuation factor αTh1 is set to a value larger than the standard attenuation factor.

If the attenuation rate α is equal to or greater than the double-feeding detection attenuation rate αTh1 (step S15: YES), it can be determined that a plurality of documents MS are being conveyed while overlapping each other, and therefore image reading is stopped. (step S16). In this case, the transport of the document MS is stopped, and the user is notified of the error by the user interface 50 . After that, this processing is terminated.

On the other hand, when the attenuation factor α is less than the double-feeding detection attenuation factor αTh1 (step S15: NO), it can be determined that only one document MS is being conveyed, and image reading is continued. Then, it is determined whether or not the image reading is completed (step S17).

Note that the trailing edge of the document MS can be detected based on the results of reading by the reading units 31 and 32 . That is, based on the results of reading by the reading units 31 and 32, it is possible to determine whether or not the trailing edge of the document MS is positioned downstream of the reading units 31 and 32 in the transport direction. Then, when the trailing edge of the document MS is located downstream of the reading units 31 and 32 in the transport direction, it can be determined that the reading of the image of the document MS has been completed.

If the reading of the image of the document MS has not been completed yet (step S17: NO), the process proceeds to step S15 described above, and the reading of the image is continued. On the other hand, if the reading of the image of the document MS is completed (step S17: YES), the process proceeds to the next step S18.

At step S18, it is determined whether or not there is a next document MS whose image should be read. If there is a next document MS (step S18: YES), the process proceeds to the above-described step S14, and transportation of the next document MS is started. In this case, the transport speed of the next document MS is equal to the transport speed of the previous document MS. On the other hand, if there is no next document MS (step S18: NO), the image data generated by the data generation section 64 is output by the data output section 65 (step S19), and this process ends.

When continuously reading the images of a plurality of manuscripts MS, the specifying button 51A may be operated by the user during the continuous reading of a series of images. In the image reading apparatus 11 of the present embodiment, such operation of the specification button 51A by the user is disabled. That is, even if the specification button 51A is operated during continuous reading of images, the transport speed of one document is made equal to the transport speed of the document next to the one document. In other words, the operation of the specifying button 51A is valid before the continuous reading of a series of images is started, that is, before the process described with reference to FIG. 5 is started.

As described above, according to the image reading apparatus 11 of the present embodiment, the following effects can be obtained.
(1) When image reading is instructed in a situation where the identification button 51A is in the OFF state, the first reading mode is performed. That is, when the user recognizes that the document MS set on the setting unit 14 is not thin, the user instructs the image reading device 11 to read an image without turning on the specification button 51A. be. At this time, the resolution of the image based on the generated image data can be selected by the user when the user inputs the reading instruction. Therefore, the document MS is conveyed at a conveying speed corresponding to the resolution of the image requested by the user, and image data of the resolution requested by the user is generated. Therefore, it is possible to provide the user with image data having a resolution desired by the user.

On the other hand, when image reading is instructed under the condition that the identification button 51A is in the ON state, the second reading mode is performed. That is, when the user recognizes that the original document MS set on the setting unit 14 is thin, the specifying button 51A is turned on and the user instructs the image reading device 11 to read an image. . At this time, although the document MS is conveyed at a lower speed than in the first reading mode, image data having the same resolution as in the first reading mode is generated. That is, it is possible to provide the user with image data that does not depend on the transport speed of the document MS while suppressing transport failures such as paper jams. Therefore, even if the transport speed of the document MS is variable, it is possible to generate image data with a resolution desired by the user.

(Second embodiment)
Next, a second embodiment in which the image reading device 11 is embodied will be described with reference to FIG. In addition, in the second embodiment, part of the processing procedure when the specification button 51A is in the ON state is different from that in the first embodiment. Therefore, in the following description, the parts that are different from the first embodiment will be mainly described, and the same reference numerals will be given to the same member configurations as in the first embodiment, and redundant description will be omitted. do.

FIG. 6 shows a flowchart for explaining the processing procedure when reading the image of the manuscript MS.
As shown in FIG. 6, it is determined whether or not the specifying button 51A is in the ON state under the condition that any one of the first mode, the second mode and the third mode is selected. (step S11). If the specifying button 51A is in the OFF state (step S11: NO), the first reading mode is selected (step S12), and the process proceeds to step S14, which will be described later. On the other hand, if the specification button 51A is on (step S11: YES), the second reading mode is selected (step S13), and the process proceeds to the next step S14.

In step S14, image reading is started by starting the selected reading mode. When the attenuation rate α detected by the double-feeding detection sensor 610 becomes equal to or greater than the double-feeding detection attenuation rate αTh1 while the image is being read in this way (step S15: YES), a plurality of Since it can be determined that the documents MS are conveyed in an overlapping state, image reading is stopped (step S16). In this case, the transport of the document MS is stopped, and the user is notified of the error by the user interface 50 . For example, the identification lamp 52A is lit. After that, this processing is terminated.

On the other hand, when the attenuation factor α is less than the double-feeding detection attenuation factor αTh1 (step S15: NO), it can be determined that only one document MS is being conveyed, and image reading is continued. Then, if the reading of the image of the document MS has not been completed yet (step S17: NO), the process proceeds to the above-described step S15, and the reading of the image of the document MS is continued. On the other hand, if the reading of the image of the document MS has already been completed (step S17: YES), the process proceeds to the next step S18.

At step S18, it is determined whether or not there is a next document MS whose image should be read. If there is no next document MS (step S18: NO), the image data generated by the data generation section 64 is output by the data output section 65 (step S19), and this process ends.

On the other hand, if there is a next document MS (step S18: YES), the process proceeds to the above-described step S11, and transportation of the next document MS is started. In other words, if the specification button 51A is changed during reading of the previous image, although the feeding speed of the document MS is changed from the time of reading the current image, the resolution of the generated image based on the image mode is the same as that of the previous image. The resolution is the same as when the image was read.

For example, if the specifying button 51A is switched from the OFF state to the ON state during reading of the previous image, the first reading mode was executed when the previous image was read, whereas the current image reading is performed in the first reading mode. Sometimes a second reading mode is implemented. That is, at the start of reading the current image, the mode to be executed is switched from the first reading mode to the second reading mode.

On the other hand, if the specification button 51A is switched from the ON state to the OFF state during the reading of the previous image, the second reading mode was executed at the time of reading the previous image, whereas the reading of the current image is performed. Sometimes a first read mode is implemented. That is, in a situation where the second reading mode is selected, when the setting information for ending the second reading mode is input, the mode to be executed is set to the second mode at the start of reading the current image. A read mode is switched to a first read mode. Therefore, in the image reading apparatus 11 of the present embodiment, the "predetermined end condition" corresponds to the fact that the specification button 51A is switched from the ON state to the OFF state by the user's operation of the specification button 51A.

As described above, according to the image reading apparatus 11 of the present embodiment, in addition to the same effect as the effect (1) of the first embodiment, the following effect can be obtained.
(2) When the images of a plurality of manuscripts MS are read continuously, if the specification button 51A is turned on while one manuscript out of the manuscripts MS is being conveyed, the image of one manuscript cannot be read. Implementation of the first reading mode continues until reading is completed. That is, while one document is being transported, the reading mode is not changed, and the transport speed of the same document is not changed. Therefore, it is possible to suppress an increase in the control load due to the switching of the reading mode during image reading.

After that, when reading the image of the next document, the second reading mode is executed instead of the first reading mode. That is, when reading the images of the first and subsequent documents, the documents are conveyed at a low speed. Moreover, since it is the second reading mode, even if the document is conveyed at a low speed, image data with the same resolution as in the first reading mode is generated. Therefore, at the time of reading the images of the documents after the first document, the user is provided with image data independent of the transport speed while suppressing the occurrence of transport failure of the same document MS by transporting the document MS at a low speed. can provide.

(3) However, when the specifying button 51A is shifted from the ON state to the OFF state while the image of the document MS is being read in the second reading mode, the execution of the second reading mode is stopped. It can be determined that the termination condition is satisfied. Therefore, when reading the image of the next document MS, the first reading mode is executed, and the document MS is conveyed at the speed specified by the first reading mode. Therefore, when the execution of the second reading mode becomes unnecessary, it is possible to appropriately switch from the second reading mode to the first reading mode.

(Third embodiment)
Next, a third embodiment of the image reading device 11 will be described with reference to FIGS. 7 and 8. FIG. In the third embodiment, the thickness of the document MS whose image is to be read is automatically detected, and whether the second reading mode or the first reading mode is to be performed is determined based on the detection result. The points to be determined are different from those in the first and second embodiments. Therefore, in the following description, the parts that are different from the first and second embodiments will be mainly described, and the same reference numerals will be given to the same member configurations as those of the first and second embodiments. duplicate explanation shall be omitted.

The control device 60 of the image reading device 11 will be described with reference to FIG.
The control device 60 includes a microcomputer including a CPU, ROM, RAM, etc., and various driver circuits. As shown in FIG. 7, the control device 60 includes a transport control section 61, a mode selection section 66, a data generation section 64, and a data output section 65 as functional sections configured by at least one of software and hardware. I'm in.

Based on the attenuation rate α detected by the double-feed detection sensor 610, the mode selection unit 66 determines whether or not the document MS being transported is thin. If it is determined that the document MS is not thin, the mode selection unit 66 selects the first reading mode (see FIG. 3) corresponding to the image resolution requested by the user, and selects the selected first reading mode. information about the reading mode (for example, the third mode) to the transport control unit 61 and the data generation unit 64 . On the other hand, when it is determined that the document MS is thin, the mode selection unit 66 selects the second reading mode, and outputs information about the selected second reading mode to the transport control unit 61 and the data generation unit 64. .

Here, an example of a method for determining whether or not the document MS being conveyed is thin will be described.
That is, when the document MS is positioned between the output unit 611 and the input unit 612 of the double feed detection sensor 610 , the sound wave output from the output unit 611 is input to the input unit 612 through the document MS. At this time, when sound waves pass through the manuscript MS, the thinner the manuscript MS, the less likely the sound waves are attenuated. That is, the thickness of the document MS can be estimated to some extent based on the attenuation factor α of the sound wave. Therefore, a determination attenuation rate αTh2 is provided as an attenuation rate that serves as a criterion for determining whether or not the thickness of the document MS is thin. I am trying to judge.

It should be noted that a plurality of thin originals MS may be conveyed in an overlapping state. For example, when two originals MS overlap each other, the attenuation factor α detected by the multi-feeding detection sensor 610 is greater than the attenuation factor when one not thin original MS is being conveyed. Therefore, the multi-feeding detection attenuation factor αTh1 is set to a value that is larger than the attenuation factor when a single not-thin document MS is being conveyed. Thus, when the attenuation rate α is equal to or greater than the determination attenuation rate αTh2 and less than the double feed detection attenuation rate αTh1, it can be determined that the document MS being conveyed is not thin. On the other hand, when the attenuation rate α is equal to or greater than the double-feeding detection attenuation rate αTh1, it can be determined that a plurality of originals MS are being conveyed in an overlapping state.

Next, with reference to the flowchart shown in FIG. 8, the processing procedure for reading the image of the document MS will be described.
As shown in FIG. 8, the document MS is started to be transported in the first reading mode according to the image resolution requested by the user (step S31). Then, when the document MS is positioned between the output portion 611 and the input portion 612 of the double-feeding detection sensor 610, it is determined whether the attenuation rate α detected by the double-feeding detection sensor 610 is less than the judgment attenuation rate αTh2. It is determined whether or not (step S32). That is, in step S32, it is determined whether or not the document MS being transported is thin.

When the attenuation rate α is less than the determination attenuation rate αTh2 (step S32: YES), it is determined that a thin document MS is being conveyed, and the reading mode is changed from the first reading mode to the second reading mode. Switch (step S33). As a result, the transport speed of the document MS is decreased. When the second reading mode is started in this manner, the identification lamp 52A is lit. Then, the process proceeds to the next step S34.

In step S34, it is determined whether or not the leading edge of the document MS has been detected by the edge detection sensor 600. FIG. If the leading edge of the document MS has not yet been detected (step S34: NO), the process proceeds to step S32 described above. On the other hand, if the leading edge of the document MS has been detected (step S34: YES), the process proceeds to step S37, which will be described later. That is, when the leading edge of the document MS passes the edge detection sensor 600 and reaches just before the reading device 30, the change of the reading mode is prohibited, and the conveying speed of the document MS is not changed.

On the other hand, in step S32, when the attenuation rate α is equal to or greater than the determination attenuation rate αTh2 (NO), it can be determined that the document MS being transported is not thin. It is determined whether or not it is less than the detected attenuation rate αTh1 (step S35). In this step S35, it is determined whether or not a plurality of originals MS are conveyed in an overlapping state. If the attenuation factor α is less than the double-feeding detection attenuation factor αTh1 (step S35: YES), it can be determined that one not thin document MS is being conveyed. The process proceeds to S34. In this case, the images are read by the reading sections 31 and 32 while the document MS is being transported at the transport speed specified in the first reading mode. Note that when the document MS is being conveyed in the first reading mode as described above, the specification lamp 52A is turned off.

On the other hand, when the attenuation rate α is equal to or greater than the double-feeding detection attenuation rate αTh1 (step S35: NO), it can be determined that a plurality of documents MS are being conveyed while being overlapped, and therefore image reading is stopped. (step S36). In this case, the transport of the document MS is stopped, and the user is notified of the error by the user interface 50 . After that, this processing is terminated.

In step S37, reading of the image of the document MS being conveyed is started. Then, it is determined whether or not the attenuation factor α detected by the double-feeding detection sensor 610 while the image is being read in this manner is less than the double-feeding detection attenuation factor αTh1 (step S38). . If the attenuation rate α is greater than or equal to the double-feeding detection attenuation rate αTh1 (step S38: NO), it can be determined that a plurality of documents MS are being transported while being overlapped, so the process proceeds to step S36 described above. migrated. That is, when it is detected that a plurality of originals MS are being conveyed in an overlapping state, the image reading that is being performed is stopped.

On the other hand, if the attenuation rate α is less than the double-feeding detection attenuation rate αTh1 (step S38: YES), it is determined whether or not the reading of the image of the document MS being conveyed is completed (step S39). If the reading of the image has not been completed yet (step S39: NO), the process proceeds to step S38 described above, and the reading of the image is continued. On the other hand, if image reading has been completed (step S39: YES), the process proceeds to the next step S40.

In step S40, it is determined whether or not there is a next document MS whose image should be read. If there is a next document MS (step S40: YES), the process proceeds to the above-described step S31, and transportation of the next document MS is started. In this case, the transport of the document MS in the first reading mode is started even after the image is read in the second reading mode. That is, the completion of reading the image of the document MS corresponds to the "predetermined end condition" for switching the mode from the second reading mode to the first reading mode.

On the other hand, if there is no next document MS (step S40: NO), the image data generated by the data generation section 64 is output by the data output section 65 (step S41), and this process is terminated.

As described above, according to the image reading apparatus 11 of the present embodiment, the following effects can be obtained.
(4) When the document MS being conveyed by the conveying device 20 is not thin, the first reading mode is performed. When the user instructs the image reading device 11 to read the image of the document MS, the user can select the resolution of the image based on the generated image data. Therefore, it is possible to provide the user with image data, which is data of an image having a resolution desired by the user.

On the other hand, when the document MS being conveyed by the conveying device 20 is thin, the second reading mode is performed. In this case, although the document MS is conveyed at a lower speed than in the first reading mode, image data having the same resolution as in the first reading mode is generated. That is, it is possible to provide the user with image data that does not depend on the transport speed of the document MS while suppressing transport failures such as paper jams. Therefore, even if the transport speed of the document MS is variable, it is possible to generate image data with a resolution desired by the user.

(5) The image reading apparatus 11 of the present embodiment determines that the thickness of the document MS being conveyed is thin when the attenuation rate α of sound waves detected by the double feeding detection sensor 610 is less than the determination attenuation rate αTh2. Therefore, the second reading mode is implemented. By using the detection result of the double feeding detection sensor 610 in this manner, the second reading mode can be automatically selected and executed.

(6) The double feed detection attenuation rate αTh1, which is the threshold value for determining whether or not a plurality of documents MS are being conveyed in an overlapping state, is set to a value larger than the judgment attenuation rate αTh2. Then, by using this multi-feeding detection attenuation factor αTh1, it is possible to determine whether only one not thin original is being conveyed, or whether a plurality of originals are being conveyed in an overlapping state. By employing such determination results, the image reading device 11 can be appropriately driven according to the situation.

(7) Note that the double feed detection sensor 610 is arranged between the transport roller pair 23 and the delivery roller pair 22 in the transport direction. Therefore, it is possible to determine whether or not the document MS being transported is thin before the leading edge of the document MS reaches the position of the reading device 30 . Therefore, it is determined whether to switch the mode from the first reading mode to the second reading mode or to continue the first reading mode before the reading of images by the reading units 31 and 32 is actually started. can do. Therefore, it is not necessary to change the transport speed of the document MS while the image is actually being read by the reading units 31 and 32 .

(8) Then, when the transport of the document MS in the second reading mode is completed, the condition for ending the second reading mode is satisfied, so the transport of the document MS in the first reading mode is started. Therefore, when reading the images of a plurality of manuscripts MS continuously, if a part of each manuscript MS is a thin manuscript, the manuscript is conveyed at a low speed only when reading the image of the thin manuscript. can do. Therefore, even when reading an image of a document that is not thin, a decrease in throughput of the image reading apparatus 11 can be suppressed as compared with the case where the document is conveyed at a low speed.

Note that each of the above embodiments may be modified as follows.
- In the third embodiment, if the double feed detection sensor 610 is arranged upstream of the reading device 30 in the transport direction, the same double feed detection sensor 610 is positioned between the feed roller pair 22 and the transport roller pair 23 in the transport direction. You may arrange|position in other positions except between. For example, the double feed detection sensor 610 may be arranged between the reading device 30 and the transport roller pair 23 in the transport direction.

If the sensor can detect whether or not the thickness of the document MS being transported is thin and whether or not multiple documents MS are being transported in an overlapping state, sensors other than the sound wave sensor can be used for double feeding. It may be applied as a detection sensor.

The larger the load applied to the pair of rollers rotating with the transport motor 26 as the driving source, the larger the current value flowing through the transport motor 26 when transporting the document MS. Such a load changes depending on the thickness of the document MS being conveyed and the number of overlapping documents MS. Therefore, in the second embodiment, it is determined whether or not the document MS being transported is thin based on the current value flowing through the transport motor 26 instead of the attenuation factor α detected by the double feed detection sensor 610. You may make it Similarly, in each of the first and second embodiments, it may be determined based on the value of current flowing through the transport motor 26 whether or not a plurality of documents MS are being transported in an overlapping state.

- In each of the first and second embodiments, the user operation for selecting the second reading mode is performed by an external device capable of communicating with the image reading device 11 instead of the user interface 50 of the image reading device 11. You may do so. In this case, the second reading mode is implemented when the control device 60 of the image reading device 11 receives specific setting information, which is information related to user operation, from the external device.

In each of the first and second embodiments, when image reading in the second reading mode is completed and image reading based on the next job is to be performed, the specification button 51A is turned off and the specification button 51A is turned off. The reading lamp 52A may be extinguished to carry out the first reading mode. In this case, inputting an image reading instruction based on the next job to the control device 60 corresponds to the "end condition".

- In each of the above embodiments, the second reading mode is executed as necessary even when the third mode is selected by the user. The second reading mode may not be performed when selected. In this case, for example, in each of the first and second embodiments, when the third mode is selected, the third mode is selected regardless of whether the specification button 51A is on or off. mode will be implemented. Further, in the third embodiment, when the third mode is selected, even if the attenuation rate α of the sound waves detected by the double feed detection sensor 610 is less than the determination attenuation rate αTh2, the third mode is selected. mode will be implemented.

- In each of the first and second embodiments, even when the specification button 51A is in the ON state, the attenuation rate α of sound waves detected by the double feed detection sensor 610 is equal to or greater than the determination attenuation rate αTh2. Occasionally, a first read mode may be implemented. Alternatively, the second reading mode may be executed when the specifying button 51A is in the ON state and the attenuation rate α of the sound waves detected by the double feed detection sensor 610 is less than the determination attenuation rate αTh2. good.

Further, when the identification button 51A is in the OFF state, the first reading mode is executed even if the attenuation rate α of the sound waves detected by the double feed detection sensor 610 is less than the determination attenuation rate αTh2. may

- The reading device 30 may be configured to include only one of the first reading section 31 and the second reading section 32 .
- The transport device 20 may be configured without the delivery motor 25 . In this case, the feed roller 21 may be rotated by driving the transport motor 26 .

The image reading device may be embodied in another device such as a facsimile device as long as it generates image data relating to an image of a document and outputs the data to an external device.

DESCRIPTION OF SYMBOLS 11... Image reading apparatus 20... Conveying apparatus as a conveying part 221, 222... Roller functioning as a delivery roller 23... Conveying roller pair 31, 32... Reading part 60... Control device as a control part 600... Edge detection sensor composed of sound wave sensors, MS: document, α: attenuation rate, αTh1: double feed detection attenuation rate, αTh2: judgment attenuation rate.

Claims (2)

a transport unit capable of transporting documents of different thicknesses;
a reading unit that reads an image of a document conveyed by the conveying unit;
An image reading device comprising: a control unit that generates image data that is data of an image read by the reading unit;
The reading unit reads an image of the document at predetermined timing when the document is conveyed by the conveying unit,
The control unit selects a first reading mode when specific setting information is not input to the control unit, and selects a second reading mode when specific setting information is input to the control unit. and select
The control unit
In the first reading mode, the reading unit reads an image from a document conveyed by the conveying unit at a speed corresponding to the required resolution, and image data of the image read by the reading unit is generated. ,
In the second reading mode, the resolution of the image read by the reading unit is read while causing the reading unit to read an image from a document conveyed by the conveying unit at a lower speed than in the first reading mode. is reduced to generate image data of an image with the same resolution as in the first reading mode, and
The control unit switches the reading mode to be performed from the second reading mode to the first reading mode when a predetermined end condition is satisfied under the condition that the second reading mode is selected,
The image reading apparatus, wherein the predetermined termination condition is that an image reading instruction based on a next job is input. The predetermined termination condition is that an image reading instruction based on the next job is input, and that the specific setting information is input from the state in which the specific setting information is being input by the user's operation. 2. The image reading apparatus according to claim 1 , further comprising switching to a state in which the image reading apparatus is not in use.

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