JP4380473B2 - Image processing device - Google Patents

Description

The present invention is related to the image processing apparatus.

  Image processing apparatuses such as copying machines and facsimile machines are provided with an image reading apparatus. Some image reading apparatuses include an automatic document feeder (ADF). As a method of reading an image of an original with this type of image reading apparatus, the original conveyed by the automatic original conveying apparatus is once laid on the platen glass and stopped, and in this state, the image of the original is moved by moving the optical scanning system. In addition to the reading method, there is known a method of reading (flow-reading) an image of a moving document conveyed by an automatic document feeder while the optical scanning system is fixed at a predetermined position. The latter method is also called CVT (Constant Velocity Transport). The former method requires the optical scanning system to reciprocate in the sub-scanning direction every time a document is read, whereas the latter method allows a plurality of documents to be continued with the optical scanning system fixed. Can be read. For this reason, the latter method can provide higher productivity than the former method.

  Also, an image processing apparatus such as a copying machine equipped with a CVT image reading apparatus needs to detect the document size before starting to read the image of the document actually conveyed by the automatic document conveying device. Many have functions. Functions that require detection of the document size before reading an image include an automatic paper selection function and an automatic magnification selection function. The automatic paper selection function is a function that automatically selects an appropriate paper size according to the original size to be scanned and the specified magnification. This is a function for automatically selecting a magnification for enlarging or reducing according to the size. Therefore, in any case, it is necessary to grasp the document size before reading.

  In the present specification, it is assumed that the document size varies depending on whether the orientation of the document is portrait or landscape, even for documents of the same standard size (A3, B4, A4, B5, letter, half letter, etc.). When an automatic document feeder transports a document, an “L” identification code is attached to the size of a vertically oriented document that is transported with the long side of the document facing the transport direction. It is assumed that an identification code “S” is attached to the size of a lateral document conveyed with the short side facing in the conveyance direction. The paper size is handled in the same manner as the document size. From this, for example, as shown in FIG. 10, there are two types of document sizes (or paper sizes) such as A4L and A4S in the document size (or paper size) of A4 depending on the orientation. .

  Generally, as a method for detecting a document size, a plurality of document detection sensors are attached to a portion where a document is set (hereinafter referred to as “document setting portion”), and the document size is determined based on the detection result of each document detection sensor. A method of detecting is known. However, in this detection method, when a plurality of originals having different sizes are processed in a mode in which the originals are mixedly mounted on the original setting unit (hereinafter referred to as an original mixed mode), the detection result of each original detection sensor depends on the maximum original size. Will be. For this reason, only the maximum document size can be detected among a plurality of documents set in the document setting unit.

  Therefore, a method is also known in which a document detection sensor is provided in the middle of the conveyance path from the document setting unit to the image reading position (position where the document image is read), and the document size is detected based on the detection result of the document detection sensor. It has been. In this detection method, a plurality of first detection sensors are provided at different positions in the main scanning direction, and the document size in the main scanning direction (hereinafter also referred to as “document width”) based on the detection results of the plurality of first detection sensors. And a second detection sensor is provided at a position where all manuscript sizes that can be handled pass, and the second detection sensor detects the passage of the leading edge of the document until the trailing edge of the document is detected. Based on this, the document size in the sub-scanning direction (hereinafter also referred to as “document length”) is detected. According to this detection method, the document size can be detected (determined) from the document width and the document length detected using the respective detection sensors even when processing in the document mixed mode.

  However, in order to grasp the document size before reading the image, it is necessary to detect the document length at a stage before the document is sent to the image reading position. For this reason, even if a detection sensor for detecting the document length is arranged in the immediate vicinity of the document setting unit, it is necessary to secure a conveyance path that is longer than the document length of the maximum handling size between the document setting unit and the image reading position. is there. Therefore, for example, if the maximum document size is A3 size, it is necessary to secure a long conveyance path of 420 mm or more between the document setting unit and the image reading position. This increases the size and weight of the automatic document feeder.

  Conventionally, the following techniques have been proposed for such problems. For example, in Patent Document 1 below, the document size is not fixed, and when the leading edge of the document reaches the image reading position, image reading is started and image data is written in the memory, and the document size is fixed. Then, a technique for reading out image data already written in a memory and performing image processing has been proposed. Also, in Patent Document 2 below, the size of a document is detected by empty conveyance in which the document is conveyed without reading an image at the image reading position, and then the document is again read using the reversing mechanism of the automatic document conveyance device. A technique for reading an image by sending it to an image reading position has been proposed. Further, in Patent Document 3 below, when a double-sided reading mode for reading images on both sides of a document is set, the size of the document is detected by idle conveyance, and then the document is recovered using the reversing mechanism of the automatic document conveyance device. A technique for reading the image in the order of the back surface and the front surface has been proposed.

JP-A-9-331418 JP-A-11-167229 JP 2002-252738 A

  However, in the technique described in Patent Document 1, it is necessary to set an image reading area in accordance with the maximum size manuscript that can be handled regardless of the size of the manuscript actually conveyed. Therefore, when the actual document size is smaller than the maximum size, it is necessary to perform processing such as cutting out a necessary area from the actual reading area for the image data written in the memory. In addition, there is a concern that the cost increases due to an increase in storage capacity and the productivity decreases due to an increase in the amount of image data. In addition, since processing is performed with the maximum size document set to a temporary document size, an error that is incomprehensible to the user may occur. For example, when A4 size paper is set in the paper storage tray of the copying machine and A3 size paper is not set, when copying an image of an A4 size document on the same A4 size paper, Assuming that the size is A3 size (maximum size) larger than A4 size and trying to process in the automatic paper selection mode, the user is prompted even though A4 size paper used for copy processing is loaded. The occurrence of an incomprehensible (unnecessary) error that A3 size paper is not set is notified.

  On the other hand, in the techniques described in Patent Documents 2 and 3, when detecting the document size before reading an image, in the single-sided reading mode in which an image on one side of the original is read, empty conveyance is performed as in the double-sided reading mode. It is necessary to go and detect the size of the document. Further, since the document surface is reversed when the idle conveyance is performed, it is necessary to carry out the idle conveyance twice before reading the image. Therefore, productivity at the time of single-sided reading is reduced.

An image processing apparatus according to the present invention includes a document transport unit that transports a document, a reading unit that reads an image of a moving document transported by the document transport unit, and a main scanning direction of the document transported by the document transport unit Output means for outputting the size information of the document, extraction means for extracting the document size candidates based on the size information in the main scanning direction of the document output from the output means, and candidates for the document size extracted by the extraction means Determining means for sequentially determining one of the temporary document sizes, and determining means for determining whether or not an error occurs when image processing is performed by applying the temporary document size determined by the determining means with the door, before reaching the image reading position by the tip reading means conveying the document by the document conveying means, one of the temporary for document size determination means for determining means has determined error When it is determined that there is no occurrence, reading of the document image is started at the image reading position, and when the determination unit determines that an error has occurred for all the temporary document sizes determined by the determination unit, the document is detected at the image reading position. An empty conveyance process for conveying an original without reading an image is performed .

  In the image processing apparatus according to the present invention, a document size candidate is extracted based on size information in the main scanning direction of the document conveyed by the document conveying means, and one of the extracted document size candidates is temporarily stored. By determining the original size, it is possible to start reading the original image before detecting the actual original size (true original size). Also, it is determined whether or not an error occurs when image processing is performed by applying a provisional document size, and if it is determined that an error occurs in the provisional document size, the provisional document size candidate is selected. By changing the size of the original, it is possible to avoid an inexplicable error occurrence notification.

  According to the present invention, when a document image is read by the CVT method by applying the document mixed mode or the like, the document image can be read while avoiding the productivity reduction and the incomprehensible error occurrence notification in the single-sided reading mode as much as possible. It can be done appropriately and efficiently.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration example of an image reading apparatus with an automatic document feeder to which the present invention is applied. The illustrated image reading apparatus 1 includes an apparatus main body 2 incorporating a reading unit, and a document pressing portion 3 supported on the apparatus main body 2 by a hinge mechanism or the like so as to be opened and closed. On the upper surface of the apparatus main body 2, a first document table 4 used in a first reading mode described later and a second document table 5 used in a second reading mode described later are arranged in parallel. Yes. Each of the first and second document tables 4 and 5 is configured using a glass substrate (transparent glass substrate or the like) having optical transparency. The first document table 4 and the second document table 5 are partitioned by an abutment guide member for positioning the document on the first document table 4.

  The document pressing unit 3 is opened and closed by a user when pressing a document placed on the first document table 4 from above. The document pressing unit 3 is provided with a document setting unit 6, a document discharge unit 7, and a document transport unit 8 which are components of the automatic document transport device. The document setting unit 6 is a portion where a document (document bundle) read in the second reading mode based on the CVT method is set, and is formed using, for example, a document supply tray. The document discharge portion 7 is a portion where a document read in accordance with the second reading mode is discharged, and is formed using, for example, a document discharge tray. The document setting unit 6 and the document discharge unit 7 are arranged in a vertical positional relationship with the document pressing unit 3.

  The document transport unit 8 transports the documents set in the document setting unit 6 one by one, moves the transported document on the second document table 5, and finally toward the document discharge unit 7. The document is discharged. The document conveying unit 8 is provided with a feeding roller 9, a first conveying roller 10, a registration roller 11, a second conveying roller 12, and a discharge roller 13. The document transport path includes a main transport path R1 from the calling roller 9 to the discharge roller 13 via the first transport roller 10, the registration roller 11, and the second transport roller 12, and the first transport path from the discharge roller 13. It is formed by a reverse conveyance path R2 that reaches the roller 10 and a reverse discharge path R3 that extends from the discharge roller 13 to the document discharge portion 7. Gate members (not shown) for guiding the traveling direction of the document are provided at the junction and branching portions of the main transport path R1 and the reverse transport path R2.

  The feeding roller 9 feeds the document set on the document setting unit 6 onto the main transport path R1. The first transport roller 10 transports the document fed by the feed roller 9 to the registration roller 11 side along the main transport path R1. The registration roller 11 feeds the document conveyed by the first conveyance roller 10 onto the second document table 5. The second transport roller 12 receives the document that has passed over the second document table 5 by the feeding of the registration roller 11 and transports it to the discharge roller 13 side. The discharge roller 13 receives the document transported by the second transport roller 12 and discharges it to the document discharge unit 7. The discharge roller 13 feeds the original conveyed by the second conveyance roller 12 to the reverse conveyance path R2 as necessary, or discharges the original to the original discharge section 7 through the reverse discharge path R3.

  Inside the apparatus main body 2, an optical scanning system 14, an imaging lens 15, and a reading sensor 16 are provided as reading means for reading an image of a document. The optical scanning system 14 includes a full-rate carriage 17 and a half-rate carriage 18 that are supported so as to be movable in the horizontal direction (direction corresponding to the sub-scanning direction) in the drawing. A lamp 19 and a first mirror 20 are mounted on the full rate carriage 17, and a second mirror 21 and a third mirror 22 are mounted on the half rate carriage 18.

  The full-rate carriage 17 and the half-rate carriage 18 move in the direction of the arrow Y using a common carriage moving motor as a drive source when reading an image of the document placed on the first document table 4. . At this time, the half-rate carriage 18 moves with a movement amount (movement speed) that is 1/2 that of the full-rate carriage 17, so that the carriage 17, 18 moves from any position in the direction of the arrow Y to the original surface. The optical path length to the reading sensor 16 is always kept constant.

  The lamp 19 irradiates light toward the original surface to be read. Reflected light from the original surface is sequentially reflected by the first mirror 20, the second mirror 21, and the third mirror 22. The imaging lens 15 forms an image of the light reflected by the third mirror 22 on the imaging surface of the reading sensor 16 at a predetermined reduction magnification. The reading sensor 16 is an image sensor for reading a document image, and is constituted by, for example, a three-line color CCD sensor. The reading sensor 16 photoelectrically converts reflected light from the document surface in units of pixels and outputs analog image signals of R (red), G (green), and B (blue).

  Here, the first reading mode is the first reading mode in which the optical scanning system 14 is moved from the preset home position (left end in FIG. 1) along the first document table 4 in the direction of the arrow Y. This is an operation mode for reading an image of an original placed on the original table 4. On the other hand, in the second reading mode, the optical scanning system 14 is stopped at a predetermined position (home position or the vicinity thereof), and the second document table 5 is moved by the conveying operation of the document conveying unit 8. This is an operation mode for reading an image of an original moving. The image reading position where the document image is read in the second reading mode is set on the second document table 5 in the document transport direction by the document transport unit 8. Therefore, in the second reading mode, the first mirror 20 of the full-rate carriage 17 is disposed immediately below the image reading position set on the second document table 5.

  The length of the main conveyance path R1 from the document setting unit 6 to the second document table 5 is set to be shorter than the maximum document size (for example, A3 size document length = 420 mm). A document length is detected in the middle of the main conveyance path R1 from the document setting unit 6 to the second document table 5 (more specifically, between the feeding roller 9 and the first conveyance roller 10). A first detection sensor 23 and a second detection sensor 24 for detecting the document width are provided. These detection sensors 23 and 24 are configured using, for example, a reflection type photosensor in which a light emitting element and a light receiving element are arranged on the same sensor surface, and when a document is present on a conveyance path facing the sensor surface. Is turned on, and is turned off when not present.

  Each of the detection sensors 23 and 24 is disposed on the downstream side of the feeding roller 9 and in the vicinity of the feeding roller 9 in the document transport direction (direction corresponding to the sub-scanning direction). In the direction orthogonal to the document transport direction (the direction corresponding to the main scanning direction), the first detection sensor 23 is located at a position where documents of all sizes that can be handled by the image reading device (automatic document transport device) pass. In contrast, a plurality of second detection sensors 24 are arranged at predetermined intervals corresponding to the standard size of each document.

  More specifically, for example, as shown in FIG. 2, the second detection sensor 24 includes five detection sensors 24A, 24B, 24C arranged in a line (on a straight line) in a direction orthogonal to the document conveyance direction (arrow direction). 24D and 24E. Then, when setting the document on the document setting unit 6, for example, assuming that one side edge of all the documents is set against the common side guide surface 25, in the direction orthogonal to the document conveyance direction, A detection sensor 24A at a position separated from the side guide surface 25 by a first distance L1, a detection sensor 24B at a position separated by a second distance L2, a detection sensor 24C at a position separated by a third distance L3, and a fourth A detection sensor 24D is arranged at a position separated by a distance L4, and a detection sensor 24E is arranged at a position separated by a fifth distance L5. These distances are set such that L1 <L2 <L3 <L4 <L5. As a specific example, the first distance L1 is set to an intermediate value of 0 to 148 mm, the second distance L2 is set to an intermediate value of 148 mm to 180 mm, and the third distance L3 is set to an intermediate value of 180 mm to 210 mm. The fourth distance L4 is set to an intermediate value of 210 mm to 257 mm, and the fifth distance L5 is set to an intermediate value of 257 mm to 297 mm.

  Subsequently, as an operation of the image reading apparatus according to the embodiment of the present invention, in particular, a basic operation when the second reading mode is set in which the image of the document set on the document setting unit 6 is read by the CVT method. The operation will be described.

  First, the originals set in the original setting unit 6 are sequentially called from the top by the calling roller 9 to the main conveying path R1, and then sent to the registration roller 11 via the first conveying roller 10. Next, the document is sent to the second document table 5 by the registration roller 11. At this time, the image of the document moving on the second document table 5 is read by the reading sensor 16 via the optical scanning system 14 and the imaging lens 15. The document that has passed through the second document table 5 is sent to the discharge roller 13 via the second conveyance roller 12. When operating in the single-sided reading mode for reading only one side image of the original, the original is discharged to the original discharge unit 7 by the discharge roller 13 as it is.

  On the other hand, when operating in the double-sided reading mode for reading the images on both sides of the document, the rotation direction of the discharge roller 13 when the trailing edge of the document is transported past the second transport roller 12 to the vicinity of the discharge roller 13. Is reversed. As a result, the document is sent from the main transport path R1 to the reverse transport path R2, and is again sent to the first transport roller 10 via the reverse transport path R2. Next, the original is sent from the first conveying roller 10 to the registration roller 11, and then sent to the second original table 5 by the registration roller 11. At this time, the original surface on which the image is first read is upward when passing through the second original table 5, so the image on the opposite side of the original surface is read by the reading sensor 16. The document that has passed through the second document table 5 is sent to the discharge roller 13 via the second conveyance roller 12.

  Thereafter, when the trailing edge of the document is transported past the second transport roller 12 to the vicinity of the discharge roller 13, the rotation direction of the discharge roller 13 is reversed again at that time. In this case, the document is sent from the main transport path R1 to the discharge reversing path R3 and is discharged to the document discharge section 7 through the discharge reversing path R3. The reason why the document is discharged through the discharge reversing unit R3 in this way is that the page order of the document set in the document setting unit 6 and the page order of the document discharged to the document discharge unit 7 when operating in the duplex reading mode. This is because of matching.

  Next, an image processing method suitable for application to an image processing apparatus such as a digital copying machine or a digital multi-functional peripheral equipped with the image reading apparatus having the above-described configuration will be described. Here, a processing procedure in the case of reading an image of an original in the second reading mode by applying the original mixed mode will be described with reference to flowcharts of FIGS. Such processing is realized by the functional configuration shown in the block diagram of FIG. In FIG. 6, the extraction unit 26 extracts document size candidates based on the output from the second detection sensor 24. The document size detection unit 27 detects the actual document size (hereinafter, true document size) based on the output from the first detection sensor 23 and the output from the second detection sensor 24. The size determination unit 28 determines one of the document size candidates extracted by the extraction unit 26 as a temporary document size, and changes the temporary document size as necessary among the document size candidates. To do. The provisional document size is applied to set parameters such as an image reading area and a reading magnification when reading of a document image is started before a true document size is determined.

  The error determination unit 29 determines whether an error occurs when image processing is performed by applying a temporary document size. The size matching determination unit 30 compares the true document size detected by the document size detection unit 27 with the provisional document size determined by the error determination unit 29 that no error will occur, thereby determining the size of both documents. It is determined whether or not they match. The error notification unit 31 notifies the user that an error will occur when it is necessary to notify the occurrence of an error during the processing by the size determination unit 28 or the processing by the error determination unit 29. is there.

  First, when a start button for instructing reading of an image is pressed in a state where a document is set in the document setting unit 6, the document conveyance unit 8 starts conveying the document (step S1). Next, when the first detection sensor 23 is switched from the off state to the on state, the time measurement by the timer is started at that time (in other words, the timing when the leading edge of the document passes the detection position of the first detection sensor 23) ( Steps S2, S3).

  Next, the on / off state of the second detection sensor 24 is confirmed (step S4). At this time, among the plurality of detection sensors 24A to 24E constituting the second detection sensor 24, the detection sensor in which the document exists at the detection position is turned on, and the detection sensor in which the document does not exist at the detection position is off. It becomes a state. For example, when the width of the document actually transported by the document transport unit 8 is larger than the distance L3 shown in FIG. 2 and smaller than the distance L4, the detection sensors 24A, 24B, and 24C are turned on. The detection sensors 24D and 24E are turned off. The on / off states of the detection sensors 24A to 24E are output as size information in the main scanning direction of the document.

  Subsequently, a document size candidate is extracted based on the on / off state of the second detection sensor 24 (step S5). This extraction process is performed by the extraction unit 26. When there are a plurality of document size candidates, all of them are extracted. Document size candidates are extracted using, for example, a document size reference table shown in FIG. The document size reference table shown in FIG. 2 is when the detection sensors 24A to 24E are arranged with the distance L1 = 70 mm, the distance L2 = 160 mm, the distance L3 = 200 mm, the distance L4 = 230 mm, and the distance L5 = 270 mm in FIG. Applicable. In the document size reference table, on / off states of the detection sensors 24A to 24E and document size candidates including priority order are registered in association with each other. As an example, under the condition that the detection sensors 24A, 24B, and 24C are on and the detection sensors 24D and 24E are off, a plurality of (four in this example) document sizes such as A4S, A5L, half letter L, and lator S are used. Candidates are registered in association with each other. Among these document size candidates, A4S is first, A5L is second, halfletter L is third, and lator S is fourth. Yes.

  Here, a method of determining the priority order assigned to the document size candidates will be described. There are several methods for determining the priority order. As a first method, a method of determining the priority order based on the use frequency of the document size assuming the use state of the user can be considered. Specifically, the priority order is determined according to the order in which the document size is expected to be used frequently. For example, when it is predicted that the usage frequency of the document size is higher in the order of A4, B5, A3, B4,..., When A4S and A5L are included in the document size candidates, A4S is given a higher priority than A5L. To do.

  As a second method, a method of determining the priority order based on the application frequency of the orientation of the document when setting the document, assuming the usage situation of the user, can be considered. Specifically, the priority order is determined according to the orientation of the document (vertical orientation, landscape orientation) that is expected to be applied frequently. For example, if it is predicted that the application direction of the document orientation is higher in landscape orientation (with identification code S) than portrait orientation (with identification code L), when A4S and A5L are included in the document size candidates, A5L is set. The priority is higher than A4S.

  As a third method, a method of determining the priority order based on the size of the document can be considered. Specifically, the priority order is determined in descending order of the document size, and conversely, the priority order is determined in descending order of the document size. For example, when A4S and A5L are included in the document size candidates, in the former case, A4S is given a higher priority than A5L, and in the latter case, A5L is given a higher priority than A4S.

  As a fourth method, when documents are sequentially conveyed one by one, a method of determining the priority order based on the document size (true document size) detected by the previous document conveyance can be considered. Specifically, if the document size candidate extracted by the previous document conveyance is included in the document size candidates extracted by the current document conveyance, the document size candidate is assigned the first priority. To do. For example, when the document size detected by the previous document conveyance is A5L and the document size candidates extracted by the current document conveyance include A4S and A5L, A5L is set as the first priority. For the second and subsequent ranks, the priority order is determined by the first method, the second method, or the third method. Further, when the document size candidates extracted in the current document conveyance do not include the document size detected in the previous document conveyance, the first method, the second method, or the third method described above. To determine the priority. In the mixed document mode, when a plurality of documents of different sizes are mixed, the same size documents may be stacked on top of each other (in other words, the same size documents may be transported continuously). Since the priority order is determined by the fourth method, the provisional document size having a high priority order increases the probability that it matches the true document size. Therefore, this is very preferable in avoiding a mismatch between the temporary document size and the true document size (size mismatch).

  Furthermore, when determining the priority order, it is also effective to switch the priority order determination method between when the first document is transported and when the second and subsequent documents are transported. For example, when the first document is transported, the priority order is determined based on the first method, the second method, or the third method, and when the second and subsequent documents are transported, the fourth method is performed. The priority order is determined based on the method. The first original refers to the original conveyed first when the start button for starting reading is pressed.

  When the document size candidates to which the priority order is assigned are extracted in this way, the document size candidate with the highest priority order is determined as a temporary document size (step S6). For example, when four document size candidates such as A4S, A5L, half letter L, and lator S are extracted with reference to the document size reference table as described above, A4S having the highest priority is temporarily selected. Determine the document size. This determination process is performed by the size determination unit 28. Subsequently, it is determined whether or not an error occurs when image processing such as copy processing is performed by applying the previously determined temporary document size (step S7). This determination process is performed by the error determination unit 29. Whether the error determination unit 29 generates an error when image processing is performed in the currently set processing mode (for example, automatic paper selection mode, automatic magnification selection mode) or processing conditions (specified paper size, variable magnification). Whether or not is determined by various parameter calculations.

  The contents of the error to be determined here include, for example, an error due to a so-called no sheet in which a sheet of a size used for the copy process (or a tray for storing the sheet) is not set, an orientation of the document and a sheet in the copy process There are errors due to vertical and horizontal misalignments, errors due to incompatibility of copy magnification in the automatic paper selection mode, errors due to incompatibility of magnification selection in the automatic magnification selection mode, and the like. In addition, for products equipped with post-processing devices such as staple processing (paper binding processing) and punch processing (paper punching processing), errors due to incompatibility of the staple position and punch position, errors due to incompatibility of the staple size and punch size, etc. Is also confirmed.

  Specific examples of error occurrence are shown in FIGS. First, in FIG. 8, when copying an image of a B4S size document onto A3S size (specified size) paper in the automatic magnification selection mode, if the provisional document size is determined to be B4S, the magnification is 115.4%. Since (B4 original → magnification adapted to A3 paper) is set, the orientation of the paper and the orientation of the copy image do not cause an error, but if the temporary original size is determined to be B5L, the magnification is 163.2%. Since (B5 original → magnification adapted to A3 paper) is set, the paper orientation does not match the copy image orientation, resulting in an error. For example, when an image of an AS3 size document is copied to an AS3 size sheet in the automatic magnification selection mode, the temporary document size is automatically determined to be A4L. The same occurs even when the original image is enlarged at the selected 141.1% magnification.

  Also, in FIG. 9, when copying an image of a B4S size document in the automatic paper selection mode in accordance with the condition of 100% magnification, if the temporary document size is determined to be B4S, the paper size is set to B4S. Therefore, an error does not occur if B4S paper is set, but if the provisional document size is determined to be B5L, the paper size is set to B5L, so even if B4S size paper is set. If no B5L size paper is set, an error occurs when there is no paper. Such an error due to the absence of paper, for example, when an A3S paper is set and an A4L paper is not set, an A3S size original image is copied in the automatic paper selection mode according to the condition of 100% magnification. In this case, the same occurs even when the temporary document size is determined to be A4L.

  If it is determined in step S7 that an error occurs in the temporary document size, another document size candidate that has not yet been determined whether or not an error has occurred among the document size candidates extracted in step S5. Is checked (step S8). If another document size candidate exists, the provisional document size is changed with priority given to the document with the highest priority (step S9). If another document size candidate does not exist, a step described later is performed. The process proceeds to S23. Processing for changing the provisional document size is performed by the size determination unit 28. Further, after changing the temporary change size in step S9, the process returns to step S7.

  As a result, for example, candidates for four document sizes such as A4S, A5L, half letter L, and lator S are extracted, and it is determined that an error occurs when A4S having the highest priority is determined as the temporary document size. In this case, the provisional document size is changed to A5L, which has the second highest priority after A4S. If it is determined that an error occurs even if the temporary document size is changed from A4S to A5L, the temporary document size is changed to the half-lator L having the second highest priority after A5L, and it is determined that an error still occurs. In this case, the temporary document size is changed to letter S. Incidentally, the processing of steps S2 to S9 is performed before the leading edge of the document conveyed by the document conveying unit 8 reaches the image reading position (before reading of the document image).

  On the other hand, if it is determined in step S7 that an error does not occur due to the temporary document size, the registration roller 11 feeds the document onto the second document table 5 (image reading position) and starts reading the document image there. (Step S10). Next, it is confirmed whether or not the true document size has been detected (step S11). If the true document size has not been detected, the process proceeds to the next step S12, and if it has been detected, the process proceeds to step S17 described later.

  In step S12, it is confirmed whether or not the first detection sensor 23 has been switched from the on state to the off state. When the first detection sensor 23 has been switched to the off state, at that time (in other words, the trailing edge of the document is the first detection sensor 23). At the time of passing through the detection position), the measured value of the timer is read (step S13). The measured value of the timer read here is that the leading edge of the document passes through the detection position of the first detection sensor 23 (the first detection sensor 23 detects passage of the leading edge of the document), and the trailing edge of the document is first. This is a value indicating the time required to pass the detection position of the detection sensor 23 (the first detection sensor 23 detects the passage of the trailing edge of the document). Next, after calculating the document length (the size of the document in the sub-scanning direction) based on the previously measured value of the timer (step S14), a true document size that matches this document length is detected (step S14). S15). This detection process is performed by the document size detection unit 27. The true document size corresponds to the size of the document actually transported by the document transport unit 8. The document size candidate extracted based on the on / off state of the second detection sensor 24 and the first detection sensor 23. It is detected by referring to the document length calculated based on the measured value of the timer that measures the ON holding time. For example, in a situation where four document size candidates such as A4S, A5L, half letter L, and lator S are extracted based on the output from the second detection sensor 24, the document length is determined based on the output from the first detection sensor 23. When the document length is calculated to be approximately 297 mm, the true document size is detected as A4S. When the document length is calculated to be approximately 148 mm in the same situation, the true document size is detected as A5L.

  Subsequently, it is determined whether or not the true document size detected in step S15 matches the provisional document size determined not to cause an error in step S7 (step S16). This determination process is performed by the size suitability determination unit 30. If it is determined that both document sizes match, the document image reading is continued (step S17). If it is determined that the two document sizes do not match, reading of the document image is interrupted (step S18), and then a return operation for re-conveying the document is performed (step S19). In this case, the image data obtained until the reading of the document image is interrupted. Further, in the document returning operation, the document transported from the second transport roller 12 to the discharge roller 13 after passing through the second document table 5 is reversed so that the rotation direction of the transport roller 13 is reversed. It is sent to the first conveying roller 10 via R2. Incidentally, since the original surface is reversed when the original is passed through the reverse conveying path R2 in the returning operation, in the single-sided reading mode, the original is again passed through the reverse conveying path R2 before the original image reading is started. However, in the double-sided reading mode, it is not necessary to pass through the reverse discharge path R3 when discharging the original by changing the reading order of the original.

  Next, after re-conveying the original (step S20), it is determined whether or not an error occurs when image processing such as copy processing is performed by applying the true original size detected in the previous step S15. (Step S21). This determination process is performed by the error determination unit 29. If it is determined that an error occurs in the true document size, the process proceeds to step S28 described later. If it is determined that an error does not occur with the true document size, the process returns to step S10 to start reading the document image. In this case, since the true document size has already been detected, reading of the document image is continued. The re-conveying of the original means that the original is conveyed again along the main conveyance path R1 in order to read the image of the original.

  On the other hand, if it is determined that an error occurs in step S7 even if all the original size candidates extracted in step S5 are applied, and there are no temporary original size change candidates, the process starts from step S8. The process moves to step S23 to carry out empty conveyance. The idle conveyance refers to a process of conveying a document without reading a document image at an image reading position. The document conveyance speed during empty conveyance is set to the same speed as the document conveyance speed during image reading.

  Subsequently, the on / off state of the first detection sensor 23 is confirmed (step S24). When the first detection sensor 23 is switched from the on state to the off state, the measured value of the timer is read at that time (step S25). Next, after calculating the document length based on the previously measured value of the timer (step S26), a true document size matching the document length is detected (step S27). This detection process is performed by the document size detection unit 27. Thereafter, the occurrence of an error is notified together with the document size detection result (step S28). This notification process is performed by the error notification unit 31. In this notification process, since the true document size is detected prior to the notification process, the user is notified that an error occurs with the true document size.

  As described above, in this embodiment, when reading an image of a document in the second reading mode to which the mixed document mode is applied, the main scanning of the document output from the second detection sensor 24 is started before the reading is started. Since the original size candidates are extracted based on the direction size information, and one of them is determined as the temporary original size, the original size is detected after the original size is detected by empty conveyance as in the prior art. It is possible to avoid a decrease in productivity in the single-sided reading mode as in the case of starting reading. In this embodiment, it is determined whether or not an error occurs when image processing is performed by applying a temporary document size. If it is determined that an error occurs, the previously extracted document size is determined. Since the tentative document size is changed among the candidates, it is possible to avoid an incomprehensible error occurrence notification as in the case where processing is performed with the maximum size set to the tentative document size as in the prior art.

  Further, in the present embodiment, when the true document size is detected during document conveyance after the reading of the document image is started, and it is determined that the detected true document size does not match the provisional document size, Since the original is re-conveyed, even when the true original size does not match the temporary original size, the image can be appropriately read by re-conveying the original.

  In addition, an error occurs when there is no temporary document size change candidate before starting to read the original image, or when it is determined that an error will occur at the true original size after starting reading the original image. Therefore, only when an error occurs at the true document size (in other words, only when an error occurrence notification is necessary), the user can be notified of the error. As a result, useless error occurrence notification can be prevented.

1 is a schematic diagram illustrating a configuration example of an image reading apparatus with an automatic document feeder to which the present invention is applied. It is a figure which shows the arrangement | positioning state of the 2nd detection sensor for document width | variety detection. FIG. 10 is a flowchart (No. 1) illustrating a processing procedure when an original image is read in a second reading mode by applying the original mixed mode. FIG. FIG. 10 is a flowchart (part 2) illustrating a processing procedure when an original image is read in the second reading mode by applying the mixed original mode. FIG. FIG. 10 is a flowchart (part 3) illustrating a processing procedure in a case where an original document mixed mode is applied and an image of an original is read in a second reading mode. 1 is a functional block diagram illustrating a main configuration of an image processing apparatus according to an embodiment of the present invention. FIG. 6 is a diagram showing a document size reference table used when extracting document size candidates. It is FIG. (1) explaining the generation example of an error. It is FIG. (2) explaining the generation example of an error. It is a figure which shows the specific example of the size description according to the direction of the original.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 6 ... Original setting part, 7 ... Original discharge part, 8 ... Original conveyance part, 14 ... Optical scanning system, 15 ... Imaging lens, 16 ... Reading sensor, 23 ... 1st detection sensor, 24 ... 2nd detection sensor, 26 ... Extraction unit, 27 ... Document size detection unit, 28 ... Size determination unit, 29 ... Error determination unit, 30 ... Size conformity determination unit, 31 ... Error notification unit

Claims (9)

An original conveying means for conveying an original;
A reading unit that reads an image of a moving document conveyed by the document conveying unit;
Output means for outputting size information in the main scanning direction of the document conveyed by the document conveying means;
Extraction means for extracting document size candidates based on size information in the main scanning direction of the document output from the output means;
Determining means for sequentially determining one of the original size candidates extracted by the extracting means as a temporary original size;
Determination means for determining whether or not an error occurs when image processing is performed by applying the provisional document size determined by the determination means;
When the determination unit determines that no error has occurred for any temporary document size determined by the determination unit before the leading edge of the document conveyed by the document conveyance unit reaches the image reading position by the reading unit. Starts reading the document image at the image reading position, and when the determination unit determines that an error has occurred for all the provisional document sizes determined by the determination unit, the document image is read at the image reading position. An image processing apparatus that performs an empty conveyance process for conveying a document without performing reading . When the determination unit determines that no error has occurred for any temporary document size determined by the determination unit, after reading the document image at the image reading position, the true document size is detected, When the true document size matches the provisional document size determined that the error has not occurred, reading of the document image is continued.
The image processing apparatus according to claim 1. When the determination unit determines that no error has occurred for any temporary document size determined by the determination unit, after reading the document image at the image reading position, the true document size is detected, When the true document size does not match the provisional document size determined that the error has not occurred, reading of the document image is interrupted.
The image processing apparatus according to claim 1. The determination unit determines that the determination unit determines that an error has occurred in any temporary document size before the leading edge of the document conveyed by the document conveyance unit reaches the image reading position by the reading unit; Change the temporary document size according to a predetermined priority order
The image processing apparatus according to claim 1. The priority order is determined based on the frequency of use of the document size used by the user.
The image processing apparatus according to claim 4. The priority order is determined based on the application frequency of the orientation of the document when the user sets the document.
The image processing apparatus according to claim 4. The priority is determined based on the true document size detected in the previous document conveyance.
The image processing apparatus according to claim 4. The priority order determination method is switched between when the first document is transported and when the second and subsequent documents are transported.
The image processing apparatus according to claim 4. The priority order is determined so that the true document size detected in the previous document conveyance becomes the first.
The image processing apparatus according to claim 7.

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