Flatbed scanner, how to produce scan data

Abstract

To solve a problem that in a case of making a small product scannable at high speed, a carriage cannot decelerate completely after the finish of reading and is brought into contact with a casing.SOLUTION: A flatbed scanner comprises: a carriage which scans a document while moving in a first direction; an acquisition unit which acquires the size of the document in the first direction; and a control unit which in a first case where the document is large, controls the carriage to scan the document while moving at a lower speed than in a second case where the document is small.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flatbed scanner and a method for producing scan data. [Background technology]

[0002] Patent Document 1 describes a method for selectively improving either the read image quality or the read speed in a scanner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-90258 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the reading speed is increased by increasing the moving speed of the carriage in a flatbed scanner, a long braking distance is required after the reading is completed. At the same time, it is also necessary to suppress the increase in product size. Therefore, when making small products that can be read at high speed, there is a problem that the carriage cannot decelerate sufficiently after the reading is completed and contacts the housing. [Means for solving the problem]

[0005] To achieve the above-mentioned object, a flatbed scanner includes a carriage that reads an original document while moving in a first direction, an acquisition unit that acquires the size of the original document in the first direction, and a control unit that reads the original document while moving the carriage at a slower speed in the first case where the original document is large than in the second case where the original document is small.

[0006] In addition, a flatbed scanner for achieving the above-mentioned object is a flatbed scanner equipped with a carriage that reads an original while moving in a first direction, and a control unit that causes the carriage to read a first original in a first time and to read a second original in a second time, wherein the first direction of the first original is A times (A>1) larger than the first direction of the second original, and the first time is a time that exceeds A times the second time.

[0007] A method of producing scan data to achieve the above objective includes, in a flatbed scanner having a carriage that reads a document while moving in a first direction, obtaining the size of the document in the first direction, and in a first case in which the document is large, reading the document while moving the carriage at a slower speed than in a second case in which the document is small.

[0008] In addition, a method of producing scan data to achieve the above-mentioned object includes, in a flatbed scanner having a carriage that reads an original while moving in a first direction, causing the carriage to read a first original in a first time, and causing the carriage to read a second original in a second time, wherein the first direction of the first original is A times (A>1) larger than the first direction of the second original, and the first time is a time greater than A times the second time. [Brief description of the drawings]

[0009] [Figure 1] Scanner block diagram. [Diagram 2] FIG. [Diagram 3] 13 is a flowchart of a scanning process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Here, the embodiments of the present invention will be described in the following order. (1)Scanner configuration: (2) Scanning process: (3) Other embodiments:

[0011] (1)Scanner configuration: FIG. 1 is a block diagram showing the configuration of a scanner 1 according to an embodiment of the present invention. The scanner 1 is a flatbed scanner that reads a document placed on a document table. The scanner 1 includes a controller 10, a reading unit 20, an operation unit 40, and a communication unit 50. The controller 10 is made up of a well-known processor. Specifically, the controller 10 may be a dedicated circuit such as an ASIC configured to execute a specific process, a CPU that reads and executes a program from a recording medium, or a SOC (System On a Chip). The SOC or ASIC may cooperate with the CPU. The controller 10 controls each unit of the scanner 1 to produce scan data.

[0012] 2 is a schematic diagram showing the reading surface of the document table T. The document table T is a transparent plate-like member such as glass, on which a document is placed by a user. The housing of the scanner 1 is provided with a document cover (not shown) that can be manually opened and closed with respect to the document table T. The reading unit 20 includes a carriage CR equipped with a light source that illuminates an object to be read such as a document, an optical system such as mirrors and lenses that guides reflected light from the object to be read, and an image sensor that receives the guided reflected light and performs photoelectric conversion to read the object to be read.

[0013] The carriage CR moves along a first direction D1 parallel to the surface of the document table T under the document table T. The first direction D1 is also called the sub-scanning direction. The image sensor is a line sensor in which a plurality of photoelectric conversion elements are arranged in a second direction D2 parallel to the surface of the document table T and perpendicular to the first direction D1. The second direction D2 is also called the main scanning direction. In this embodiment, the light source is a white light source. The image sensor is configured with three rows of photoelectric conversion elements, and each row of photoelectric conversion elements is provided with a filter of each color of red (R), green (G), and blue (B). The carriage CR moves along the first direction D1 by a power mechanism (not shown) such as a motor and gears. The controller 10 controls the drive of the power mechanism to move the carriage CR and cause the image sensor to read the document placed on the document table T.

[0014] The image sensor includes an analog front end (not shown). The analog front end includes a circuit that applies gain to the signal output by the photoelectric conversion element according to the amount of received light and outputs the signal, and a circuit that performs A / D conversion. The analog front end adjusts the gain based on information indicating the gain to make the black level of the image sensor the minimum output value and the white level the maximum output value. The controller 10 acquires a signal as a result of reading from the image sensor. The controller 10 performs image processing on the acquired signal to generate scan data, which is image data in a predetermined format. The controller 10 can transmit the generated image data (scan data) to an external device (PC2 in this embodiment) via the communication unit 50.

[0015] The communication unit 50 is a device for communicating with an external device such as the PC 2, and the controller 10 can transmit any information including scan data to the PC 2, and can also receive various instructions and the like from the PC 2. In this embodiment, the controller 10 can obtain information indicating document reading conditions and a scan start instruction from the PC 2. The operation unit 40 includes an input unit that accepts operations by the user. The user can also perform operations such as a scan start instruction on the operation unit 40. The controller 10 accepts the user's instructions via the operation unit 40.

[0016] In this embodiment, as shown in Fig. 2, in the scanner 1, a home position HP is defined near one end T1 in the first direction D1 of the document table T. The home position HP is a position where the carriage CR waits when no reading is being performed. A reference plate 21 is disposed near the home position HP. The document table T is disposed on the opposite side of the reference plate 21 from the home position HP of the carriage CR. The white level and black level are determined based on the measurement results of the reference plate 21.

[0017] The reference plate 21 has a length approximately equal to that of the carriage CR in the second direction D2. The controller 10 corrects the reading result of the document read by the image sensor, based on the white level and the black level.

[0018] When the controller 10 receives information indicating the reading conditions and a scan start instruction from the PC 2, the controller 10 obtains the reading settings necessary for the reading operation from the information indicating the reading conditions. The information indicating the reading conditions includes information indicating color / monochrome selection, output resolution, and the reading range on the platen T. The output resolution is a resolution designated by the user as the resolution of the scan data to be finally output, and the controller 10 determines the reading resolution according to the output resolution.

[0019] In this embodiment, the image sensor can perform reading at a reading resolution of either 300 dpi or 600 dpi. The user can select one of several resolutions between 150 dpi and 600 dpi as the output resolution on the PC 2 and instruct the scanner 1 as the reading condition. The controller 10 selects 300 dpi (second resolution) or 600 dpi (first resolution) as the reading resolution according to the instructed output resolution and performs reading. For example, if the output resolution is equal to or greater than a threshold, 600 dpi is selected, and if it is less than the threshold, 300 dpi is selected. In this way, the correspondence between the output resolution and the reading resolution is predetermined. Note that the controller 10 performs a resolution conversion process on the image data generated by reading at 300 dpi or 600 dpi to generate image data with the output resolution specified by the user.

[0020] The information indicating the reading range is expressed, for example, by the coordinates of the reading start position in the first direction D1, the distance from the reading start position in the first direction D1, and the distance in the second direction D2. The reading start position may be a reading origin O that is predefined on the plane of the manuscript table T, or may be an arbitrary position. Note that a plurality of manuscript size detection sensors (not shown) are provided at a plurality of locations below the manuscript table T, and when automatic detection of the manuscript size is instructed, the controller 10 can determine the manuscript size and orientation from the output of each sensor and obtain the coordinates indicating the reading range. For example, an optical sensor is used as the manuscript size detection sensor, and it can detect whether or not a manuscript is placed at the installation position of the sensor. In this manner, the controller 10 can obtain the size of the manuscript in the first direction. In this case, the controller 10 functions as an acquisition unit.

[0021] Next, the operation of the carriage CR when reading a document will be described. In this example, the description will be continued assuming that the end of the readable range on the T1 side is the readable start position SP, which is the read origin O. Note that the rectangular area indicated by the dashed line in FIG. 2 indicates the readable range by the image sensor. The end of the readable range on the T1 side is the readable start position SP, and the end of the readable range on the T2 side is the read limit position L3. In this embodiment, the maximum size of the document that can be read by the scanner 1 is the legal size. The legal size has a short side that is approximately 6 mm larger than the short side of the A4 size, and a long side that is approximately 60 mm larger than the long side of the A4 size. In this embodiment, the length of the first direction D1 of the readable range indicated by the dashed line is approximately equal to the length of the long side of the legal size document.

[0022] When receiving a scan start command, the controller 10 moves the carriage CR from the home position HP to the reference plate 21 to read the reference plate 21. The controller 10 then accelerates the carriage CR to a preset reading speed before it reaches the reading start position SP from the reference plate 21, and moves the carriage CR from the position of the reading origin O to the end of the document on the end T2 side in the first direction D1 while maintaining a constant reading speed, and causes the image sensor to read the document. If the reading speed (movement speed of the carriage CR) changes during the period when the document is read, it may affect the image quality, so the controller 10 moves the carriage CR at a constant speed during the reading period. When reading up to the end of the document on the end T2 side is completed, the controller 10 decelerates the carriage CR according to a preset deceleration procedure according to the characteristics of the motor, and finally stops the carriage CR. The braking distance required from the reading end position is determined according to the reading speed. When reading at 300 dpi, it is possible to move the carriage CR and read at a higher speed than when reading at 600 dpi, which is a high resolution. The explanation will be continued assuming that when reading is performed at 300 dpi, speed V1 can be adopted as the reading speed.

[0023] In FIG. 2, L1 is the end position of the carriage CR that can move. That is, the carriage CR can move until it reaches the movement limit position L1. L2 is a position that is separated toward the end T1 by the braking distance K1 required to stop the carriage CR at the movement limit position L1 when the reading resolution is 300 dpi and the reading speed is speed V1. In other words, the braking distance K1 of the carriage CR when the reading speed is speed V1 is longer than the distance K2 between the maximum size of the document that can be read and the movement limit position L1 of the carriage CR. In other words, the distance K1 from the position L2 to the movement limit position L1 is longer than the distance K2 between the reading limit position L3, which is the end on the T2 side of the readable range (the range of the dashed line in FIG. 2), and the movement limit position L1.

[0024] Therefore, when the reading end position of the document is on the end T1 side of position L2, the carriage CR reads the document up to the end of the document while moving at speed V1, and then decelerates and can stop at the latest by the movement limit position L1. In this embodiment, when an A4 size document is placed so that its long side is parallel to the first direction D1 and in contact with the reading origin O, the size of the document table T is designed so that the end on the T2 side is closer to the T1 side than position L2. Therefore, in this embodiment, an A4 size document can be read at speed V1.

[0025] When a legal size document is placed on the document table T with its long side parallel to the first direction D1 and in contact with the reading origin O, in this embodiment, the end of the document on the T2 side is at the reading limit position L3 on the T2 side from the position L2. Therefore, assuming that the carriage CR is moved at a speed V1 to perform reading, it is considered that if it is decelerated according to the deceleration procedure, it cannot stop at the movement limit position L1 and will come into contact with the wall of the housing of the scanner 1. On the other hand, if it is decelerated suddenly without following the deceleration procedure, it may shorten the life of the motor, so it is not preferable to decelerate suddenly. That is, in the case of the scanner 1, when reading is performed at a fixed reading speed V1 at 300 dpi, which is the second resolution, there is a problem that the carriage comes into contact with the wall of the housing as described above depending on the size of the document in the first direction D1.

[0026] Therefore, in this embodiment, the controller 10 controls the carriage CR to move at a slower speed to read the original in the first case where the original is large than in the second case where the original is small. In this case, the controller 10 functions as a control unit. Specifically, the controller 10 determines the reading resolution from information indicating the reading conditions acquired from the PC 2. As described above, in this embodiment, the image sensor can perform reading at a reading resolution of either 300 dpi or 600 dpi.

[0027] When reading at 300 dpi, the controller 10 acquires the size of the document in the first direction D1. Specifically, the controller 10 acquires the reading start position and reading end position of the document in the first direction D1, and determines whether the reading end position is on the T1 side of position L2. If the reading end position is on the T1 side of position L2 (second case), the controller 10 performs reading at a reading speed of speed V1. Because the reading end position is on the T1 side of position L2, the carriage CR can be stopped by the movement limit position L1 by decelerating the carriage CR from the reading end position according to a predetermined deceleration procedure.

[0028] When reading is performed at 300 dpi and the reading end position is on the T2 side of position L2 (first case), the controller 10 performs reading at a reading speed V2, which is slower than speed V1. The braking distance when reading at speed V2 is shorter than the braking distance when reading at speed V1. In this embodiment, when reading at speed V2, even if the original is longer than the length from reading start position SP to position L2, the carriage CR can be stopped by movement limit position L1 by decelerating from speed V2 according to a predetermined deceleration procedure, so long as it is up to reading limit position L3.

[0029] When reading at 600 dpi, in this embodiment, reading is performed at a reading speed V3 that is slower than the speed V1. Since the speed V3 is smaller than the speed V1, the braking distance when reading at 600 dpi (speed V3) is shorter than the braking distance when reading at 300 dpi (speed V1). In this embodiment, when reading at 600 dpi (speed V3), both a document shorter than the length from the read start position SP to the position L2 and a document longer than the length (document up to the read limit position L3 on the T2 side from the position L2) can be read at the same speed V3. Furthermore, up to the read limit position L3, the carriage CR can be stopped by the movement limit position L1 by decelerating from the speed V3 according to a predetermined deceleration procedure.

[0030] In this embodiment, the speed V3 is slower than the speed V2. That is, in this embodiment, V1>V2>V3, and reading can be performed using three different speeds depending on the combination of reading resolution and document size. In general, when 300 dpi is selected as the reading resolution, high-speed reading is expected. Since the reading speed V2 is faster than the reading speed V3, when reading at 300 dpi and reading a large-sized document (where the reading end position is on the T2 side of position L2), the document can be read in a shorter time than when reading at 600 dpi.

[0031] As described above, when reading at 300 dpi, the condition for determining whether to switch the reading speed between V1 and V2 is the size of the document in the first direction D1. The determination is made without depending on the size of the document in the second direction D2 perpendicular to the first direction D1. Therefore, the controller 10 reads the document while moving the carriage at a speed that is not dependent on the size of the document in the second direction D2.

[0032] Furthermore, when the carriage CR is caused to read the first document in a first time and the carriage CR is caused to read the second document in a second time, the first direction of the first document is A times (A>1) the size of the second document in the first direction, and the first time is a time exceeding A times the second time. For example, consider the case where an A4 size document (second document) and a legal size document (first document) are read at 300 dpi. The size of the long side of the legal size document (first document) is A times (A>1) the size of the long side of the A4 size document (second document). If the length of the long side of the A4 size document is K, the length of the long side of the legal size document is AK. When these documents are placed on the document table T so that the long side is parallel to the first direction D1 and the short side is in contact with the read start position SP and read, the movement time of the carriage CR for reading is set as a first time for the legal size document (first document) and a second time for the A4 size document (second document). The A4 size document (second document) is read by moving the carriage CR at a reading speed V1, so the second time is K / V1. The legal size document (first document) is read by moving the carriage CR at a reading speed V2, so the first time is AK / V2. Therefore, the first time is A (V1 / V2) times the second time. Since V1>V2, the first time is a time that exceeds A times the second time. In this embodiment, the legal size document (first document) is the largest document that the scanner 1 can read.

[0033] As described above, according to this embodiment, when reading a document size (such as A4 size) that is expected to be used relatively frequently at 300 dpi, high-speed reading is possible. In addition, documents with longer sides than A4, such as legal size, can also be read. In the case of such large documents, even when reading at 300 dpi, the reading speed is slower than that of A4 (but faster than the reading speed at 600 dpi), thereby preventing the carriage CR from coming into contact with the housing. This makes it possible to suppress an increase in the size of the housing.

[0034] (2) Scanning process: 3 is a flowchart showing the scan process. The scan process is started when a scan start instruction is received from the PC 2. When the scan process is started, the controller 10 acquires the reading settings (step S100). That is, the controller 10 acquires the reading settings such as information indicating the reading range, color / monochrome selection, reading resolution (300 dpi or 600 dpi), etc., based on the information indicating the reading conditions.

[0035] Next, the controller 10 sets the reading speed according to the reading settings (step S105). That is, when the reading resolution is 300 dpi, the controller 10 selects the speed V1 as the reading speed, and when the reading resolution is 600 dpi, the controller 10 selects the speed V3 as the reading speed. Next, the controller 10 judges whether the reading resolution is 300 dpi (step S110). When it is judged in step S110 that the reading resolution is 300 dpi, the controller 10 judges whether the reading range exceeds the range that can be read at the speed V1 (step S115). That is, the controller 10 judges whether the reading end position exceeds the position L2.

[0036] If it is determined in step S115 that the reading range exceeds the range that can be read at the speed V1, the controller 10 changes the reading speed (step S120). That is, the controller 10 selects the speed V2 as the reading speed. After executing step S120, or if it is not determined in step S110 that the reading resolution is 300 dpi, or if it is not determined in step S115 that the reading range exceeds the range that can be read at the speed V1, the controller 10 performs a scan process (step S125). That is, the controller 10 moves the carriage CR from the home position HP to the reference plate 21 to read the reference plate 21, accelerates the carriage CR to the above-mentioned selected reading speed from the reference plate 21 to the reading start position, moves the carriage CR while maintaining the reading speed from the reading start position to the reading end position to make the image sensor perform reading, and when reading is completed at the reading end position, decelerates the carriage CR until it stops according to a predetermined deceleration procedure.

[0037] (3) Other embodiments: The above embodiment is an example for implementing the present invention, and various other embodiments can be adopted. For example, the present invention can be applied to a multifunction peripheral equipped with a flatbed scanner. When applied to a multifunction peripheral, the present invention can be applied to all jobs that involve reading (e.g., scan jobs, copy jobs, fax jobs, etc.). Therefore, the scan data can be used in various ways, and can be stored in a recording medium (not shown) equipped in the scanner 1, can be stored in a portable recording medium, can be transmitted to an external device, can be used for printing, or can be transmitted by fax.

[0038] The color of the light source and the type of the image sensor are not limited to those in the above embodiment, and various combinations can be adopted. Either a method of reading by sequentially switching between RGB light sources or a method of reading using a white light source may be used, a reduction optical method may be used in a CIS method, and either a CCD sensor or a MOS sensor may be used. In the above embodiment, the combination of Legal and A4 is used as an example of the combination of the document size in the first case and the document size in the second case, but other combinations may be used. For example, the document size in the first case may be A4 size, and the document size in the second case may be Letter size (the long side is shorter than the long side of A4), or the document size in the first case may be B0 size and the document size in the second case may be A0 size, etc. In addition, when reading an arbitrary range within a document, even if the document size and the orientation when placed are the same, the present invention can be applied to various reading modes in which the reading end position in the first direction is closer to the reading limit position L3 in the first case than in the second case. Furthermore, the document size and reading speed may be associated in three or more stages, such as setting a reading speed faster than that in the second case in the third case in which a document smaller than the second case is read.

[0039] The distance from the white reference position to the document may be longer than the distance from the document to the wall of the housing at the end in the first direction in the first direction in the first case. For example, assume that the length of the document in the first direction D1 in the first case is the same as the length of the readable range in the first direction D1 shown by the dashed line. The wall of the housing at the end in the first direction is the wall of the housing of the scanner 1. The inner wall surface H of the housing is located away from the movement limit position L1 by a small margin. In this case, the distance K3 from the reference plate 21 to the read start position SP (the distance from the white reference position to the document) may be configured to be longer than the distance K4 from the read limit position L3 to the inner wall surface H (the distance from the document to the wall at the end in the first direction). Specifically, the distance K3 from the reference plate 21 to the read start position SP is the distance required for acceleration to the reading speed, and is the distance required for acceleration to the reading speed and constant constant speed movement at the reading speed (because the reading speed needs to be stable by SP). For example, when accelerating from the reference plate 21 with the same initial speed and acceleration, the distance required for acceleration to the reading speed is longer in the second case (reading speed V1) than in the first case (reading speed V2). Therefore, the distance from the reference plate 21 to the reading start position SP is designed to at least meet the distance required for acceleration in the second case. The carriage CR starts accelerating the reference plate 21 at a preset initial speed, accelerates to speed V1 by a preset acceleration procedure before reaching the reading start position SP, and transitions to a constant speed, and reaches the reading start position SP. The distance K2 from L3 to L1 is the braking distance required to stop from speed V2 (because this is the first case), and the distance K4 from L3 to the inner wall surface H is the braking distance K2 plus a small margin. The speed V2 is slower than the speed V1. Also, like acceleration before a reading operation, no distance is required to stabilize the speed (or, even if necessary, it is shorter than during acceleration). Therefore, the distance K4 from the reading limit position L3 to the inner wall surface H can be configured to be shorter than the distance K3 from the reference plate 21 to the reading start position SP. The home position of the carriage may be on the T2 side of the platen. In this case, it is possible to move the carriage to the T1 side of the platen before starting to read the document.

[0040] The scanner may be configured to read at multiple resolutions, or may be configured to read at a single resolution. In the former case, it may be possible to read at three or more resolutions. If it is possible to read at multiple resolutions, it may be configured to change the reading speed depending on the document size when reading at any of the resolutions, or it may be configured to change the reading speed depending on the document size when reading at all resolutions.

[0041] The flatbed scanner only needs to be able to read documents of different sizes, such that when the carriage is caused to read a first document in a first time and the carriage is caused to read a second document in a second time, the first direction of the first document is A times (A>1) larger than the size of the second document in the first direction, and the first time exceeds A times the second time. In this case, the first document may be a document of the maximum size that the flatbed scanner can read. It is sufficient that the above relationship is satisfied at least for documents of the maximum size. Therefore, the above relationship may also be satisfied for documents of sizes other than the maximum size.

[0042] Furthermore, the present invention can be applied as a program or method executed by a computer. The above-mentioned system, program, and method may be realized as a single device or may be realized by using parts of multiple devices, and include various aspects. In addition, it can be modified as appropriate, such as being partly software and partly hardware. Furthermore, the invention can be established as a recording medium of a program that controls the system. Of course, the recording medium of the program may be a magnetic recording medium or a semiconductor memory, and any recording medium developed in the future can be considered in the same way. [Explanation of symbols]

[0043] 1...scanner, 10...controller, 20...reading unit, 21...reference plate, 40...operation unit, 50...communication unit, CR...carriage, HP...home position, L1...movement limit position, L2...position, L3...reading limit position, O...reading origin, SP...reading start position, T...original table, T1...edge, T2...edge

Claims

1. A sensor that moves at a constant speed during a reading period in a first direction perpendicular to a direction in which a plurality of photoelectric conversion elements are arranged. A carriage that reads the document, The carriage is caused to read a first document, and the carriage is caused to read a second document. A control unit A flatbed scanner comprising: The first direction of the first original is A times (A>1) larger than the second direction of the first original. a first time taken to read the first document is equal to a time taken to read the second document, The time is more than A times the second time taken for the Flatbed scanner.

2. The first document is a document of the maximum size that the flatbed scanner can read. The manuscript, 2. The flatbed scanner of claim 1.

3. A sensor that moves at a constant speed during a reading period in a first direction perpendicular to a direction in which a plurality of photoelectric conversion elements are arranged. In a flatbed scanner having a carriage for reading a document, The carriage is caused to read a first document, and the carriage is caused to read a second document. This includes: The first direction of the first original is A times (A>1) larger than the second direction of the first original. a first time taken to read the first document is equal to a time taken to read the second document, The time is more than A times the second time taken for the How the scan data is produced.

Images