Sheet detection apparatus, sheet detection apparatus control method, and program

Abstract

To detect the width of a transparent sheet without adding a hard constitution for detecting the transparent sheet.MEANS FOR SOLVING THE PROBLEM: An embodiment of the present invention is a sheet detection apparatus which comprises: conveyance means for conveying a sheet in a first conveyance direction; reading means for reading the sheet conveyed by the conveyance means; and control means for controlling the conveyance means and the reading means. The conveyance means comprises, as plural rollers, a first roller located upstream and closest to the reading means, and a second roller located downstream and closest to the reading means, in the first conveyance direction. The control means executes rotation control of the first roller and the second roller so that a first conveyance velocity of the sheet at a position of the first roller and a second conveyance velocity of the sheet at a position of the second roller are differentiated before the sheet is read by the reading means.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a sheet detection device, a control method and a program for the sheet detection device, and more particularly to a technique for detecting the edge of a sheet and detecting the paper width in a recording device. [Background technology]

[0002] Conventionally, image recording devices that record images on sheets have adopted a configuration in which an image is recorded on a sheet while the sheet is transported along a transport path. In addition to the widely used plain paper, many types of sheets are used to meet various applications, one of which is transparent sheets. Furthermore, in image recording devices, the printable area varies depending on the sheet size, so the sheet size must be specified before printing.

[0003] Sheets on the conveyance path of an image recording device are usually flat. Therefore, when recording on a transparent sheet, it is difficult to detect the edge of the sheet when the transparent sheet is read by the reading unit, and the size of the sheet cannot be accurately determined. In other words, when a transparent sheet on the conveyance path is read by the reading unit, the result is very similar to when the conveyance path is read directly (i.e., when there is no transparent sheet). Therefore, it is difficult to distinguish between when there is a transparent sheet and when there is no transparent sheet, and to detect the edge of the sheet, which makes it difficult to determine the size of the sheet.

[0004] To solve this problem, in Patent Document 1, a polarizing filter is placed between a laser projector that irradiates the area near the side edge of the conveyed transparent sheet and a light receiver. The edge of the transparent sheet is detected by utilizing the difference in phase between the light that has passed only through the polarizing filter and the light that has passed through both the polarizing filter and the transparent sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 8-337354 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, a hardware configuration for detecting the transparent sheet must be added, which increases costs.

[0007] In view of the above problems, the present disclosure aims to detect the paper width of a transparent sheet without adding a hardware configuration for detecting the transparent sheet. [Means for solving the problem]

[0008] One embodiment of the present invention is a sheet detection device having a conveying means for conveying a sheet in a predetermined first conveying direction, a reading means for reading the sheet conveyed by the conveying means, and a control means for controlling at least the conveying means and the reading means, wherein the conveying means includes a plurality of rollers, the plurality of rollers including a first roller located upstream of the reading means and closest to the reading means in the first conveying direction, and a second roller located downstream of the reading means and closest to the reading means, and the control means performs rotation control of the first roller and the second roller so as to make a first conveying speed of the sheet at the position of the first roller different from a second conveying speed of the sheet at the position of the second roller before the sheet is read by the reading means. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to detect the paper width of a transparent sheet without adding a hardware configuration for detecting the transparent sheet. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an inkjet recording apparatus 100. [Figure 2] 1 is a perspective view showing a scanner device 106 and its peripheral configuration; [Figure 3] FIG. 1 is a front view showing the scanner device 106 and its peripheral configuration. [Figure 4] Block diagram showing the control configuration of the inkjet recording apparatus 100 [Figure 5] Flowchart of a series of processes including transparency sheet detection [Figure 6] An example of the results of scanning a transparent sheet DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the components described below are merely examples and are not intended to limit the scope of the present disclosure.

[0012] <Configuration of Inkjet Recording Apparatus> FIG. 1 is a cross-sectional view that schematically illustrates an inkjet recording apparatus 100 (hereinafter simply referred to as recording apparatus 100) as a sheet detection device according to an embodiment of the present disclosure. The recording apparatus 100 is an apparatus that records an image on a recording medium (recording an image on a recording medium is also referred to as printing). In this embodiment, as shown in the figure, roll paper 110 is used as the recording medium. Roll paper is continuous paper that can be used for continuous printing. The recording apparatus 100 has a paper feeder 103 that transports the roll paper 110, a main body 111 that actually performs printing, a paper discharger 104 that takes up the roll paper 110, and an operation panel 101.

[0013] The paper feeder 103 is a device that supplies roll paper 110 to the main body 111. The paper feeder 103 rotates the paper tube of the roll paper 110 around a rotation axis 112, and transports the roll paper 110 wound around the paper tube toward the recording device 100 at a constant speed via multiple rollers 115, which serve as transport means. The rollers 115 are, for example, transport rollers, paper feed rollers, and dancer rollers for tension control.

[0014] The paper discharge device 104 is a device that winds up the roll paper 110 transported from the main body 111 into a roll around a paper tube. The paper discharge device 104 rotates the paper tube of the roll paper 110 around a rotating shaft 113, and winds the roll paper 110 transported on the paper tube at a constant speed onto the rotating shaft 113 as a finished roll paper via multiple rollers 115, which form a transport section. In the paper discharge device 104, as shown in the figure, the roll paper 110 is wound around the paper tube of the rotating shaft 113 and held in a roll shape.

[0015] Before printing begins, roll paper 110 is passed from paper feeder 103, through main body 111, and into paper discharge device 104. More specifically, roll paper 110 is set on rotation shaft 112 of paper feeder 103, and the leading edge of roll paper 110 is passed over skew correction device 109. Next, it passes under inkjet recording head 102 provided in main body 111, under drying device 105, and over cooling devices 107 and 108. The roll paper 110 then passes between scanner device 106, which serves as reading means, and lift-up unit 116, and is wound around rotation shaft 113 of paper discharge device 104. In scanner device 106, light emitted from a light source is directed onto the roll paper, and the light reflected by the roll paper is optically read using an optical sensor. The direction in which the roll paper 110 is transported at the position of the scanner device 106 is defined as the X-axis direction, the depth direction of the device as the Y-axis direction, and the up-down direction of the device as the Z-axis direction, with the positive and negative directions of each axis set as shown in the figure. This coordinate system will also be used in other drawings described later in this specification. After the roll paper 110 is fed through the recording device 100, a print job is created using the control PC 114 of the recording device 100, and the created print job is submitted to the recording device 100. After submitting the print job, the user presses the print start button displayed on the operation panel 101 to begin printing.

[0016] <Configuration of the scanner device> FIG. 2 is a schematic diagram showing the scanner device 106, which serves as a reading unit, and its surroundings. It is a bird's-eye view from above the device. A sheet P, which is roll paper 110, is transported in the transport direction, i.e., the positive direction of the X axis (from right to left in the figure), by multiple rollers 115, which serve as a transport unit. The transport speed of the sheet P near the scanner device 106 is controlled using an upstream transport roller 204, which is located closest upstream in the transport direction as viewed from the scanner device 106, and a downstream transport roller 205, which is located closest downstream. The transport speed of the sheet P at the position of the upstream transport roller 204 is controlled to a desired speed using multiple rollers 115 located upstream of the upstream transport roller 204 in the transport direction. The transport speed of the sheet P at the position of the downstream transport roller 205 is controlled to a desired speed using multiple rollers 115 located downstream of the downstream transport roller 205 in the transport direction. The upstream transport roller is referred to as the first roller, and the downstream transport roller is referred to as the second roller. The rotation speed of the upstream transport roller is referred to as the first rotation speed, and the rotation speed of the downstream transport roller is referred to as the second rotation speed. Furthermore, the transport speed of the sheet P at the position of the upstream transport roller is referred to as the first transport speed, and the transport speed of the sheet P at the position of the downstream transport roller is referred to as the second transport speed.

[0017] The sensors 202A and 202B are optical sensors. When using these sensors to read a sheet included in the reading area 203, the rotation speed of the upstream conveyance roller 204 and the rotation speed of the downstream conveyance roller 205 are changed to control the conveyance speed of the sheet P to be slower. The sensors 202A and 202B are arranged in a staggered configuration on the side of the scanner device 106 facing the sheet P so that some of their reading areas overlap in the Y-axis direction. The sensors 202A and 202B are configured to include an imaging element (not shown), such as a CCD sensor or a CMOS sensor. The read image of the reading area 203 obtained as a result of reading by the scanner device 106 is used to calculate various correction values and detect the paper width by detecting the sheet edges. An example of paper width detection will be described later.

[0018] 3 is a front view showing the configuration of the scanner device 106, which is a reading unit, and its surroundings. The scanner device 106 is positioned above the sheet P, and a lift-up unit 116 is provided opposite the scanner device 106, across the conveyance path of the sheet P. An elevation unit 207 located above the lift-up unit 116 is movable in the positive or negative direction of the Z axis, which is the direction perpendicular to the conveyance direction of the sheet P (i.e., up and down), and can move upward to press the sheet P against the scanner device 106. A black plate provided on the top surface of the elevation unit 207 can press the sheet P over the entire reading area that can be read by the scanner device 106.

[0019] 3(a) shows the conveyance state of the sheet P in the normal mode when the scanner device 106 is not used, and as shown in the figure, the sheet P is in a flat state with respect to the scanner device 106. In the normal mode, the rotation speed of the upstream conveyance roller 204 and the rotation speed of the downstream conveyance roller 205 are equal.

[0020] FIG. 3B shows the conveyance state of a sheet P in a mode (reading / inspection mode) for detecting the paper width by detecting the edges of a non-transparent sheet (hereinafter referred to as a non-transparent sheet). In this embodiment, the range of light emitted from the light source of the scanner device 106 is limited to approximately 300 to 500 mm for a CCD and 20 to 50 mm for a CIS. In normal mode, the distance from the light source to the sheet P is outside of this range. Therefore, in the reading / inspection mode for reading the sheet P using the scanner device 106, as shown in FIG. 3B, before conveyance of the sheet P begins, the lifting / lowering unit 207 is moved upward, i.e., in the positive direction of the Z axis (from bottom to top in the figure), to press the sheet P. When the lifting / lowering unit 207 is moved upward, i.e., in the positive direction of the Z axis, the nip pressure of the upstream conveyance roller 204 and the nip pressure of the downstream conveyance roller 205 are reduced. This allows the sheet P to move along with the lifting of the lifting unit 207 on both the upstream and downstream sides of the scanner device 106 in the transport direction. The aforementioned reading inspection mode is a mode in which reading is performed to calculate various correction values or the paper width is detected by detecting the edges of a non-transparent sheet.

[0021] 3(c) shows the conveyance state of sheet P in a mode in which paper width detection is performed by detecting the edges of a transparent sheet (transparent sheet paper width detection mode). By changing the rotation speed of upstream conveyance roller 204 and downstream conveyance roller 205, sheet P is curved as shown in the figure, and the distance between sheet P and scanner device 106 is changed. The curvature of sheet P shortens the distance from scanner device 106 to sheet P. When this distance is about 20 mm (included in the range of light from the light source of scanner device 106), sheet P, which is a transparent sheet, can be read by scanner device 106.

[0022] When the rotation speed of the downstream transport roller 205 is made slower than the rotation speed of the upstream transport roller 204, the curvature of the sheet P increases depending on the duration of this state, and the distance between the sheet P and the scanner device 106 decreases. When the rotation speed of the upstream transport roller 204 and the rotation speed of the downstream transport roller 205 are made equal while the sheet P is in a curved state, the curved state of the sheet P is maintained. When the rotation speed of the downstream transport roller 205 is made faster than the rotation speed of the upstream transport roller 204 while the sheet P is in a curved state, the curvature of the sheet P decreases depending on the duration of this state, and the distance between the sheet P and the scanner device 106 increases.

[0023] <Control configuration of recording device> 4 is a block diagram showing the control configuration of the recording device 100. The recording device 100 is mainly composed of a print engine unit 400 that controls the print engine, and a controller unit 300 that controls the entire recording device. A print controller 402 (control means) controls various mechanisms of the print engine unit 400 according to instructions from a main controller 301. The control configuration will be described in detail below.

[0024] The controller unit 300 has a main controller 301 configured by a CPU. The main controller 301 controls the entire printing apparatus in accordance with programs and various parameters stored in a ROM 306, using a RAM 305 as a work area. For example, when a print job (including print setting information and image data) is input from a host device 500 via a host I / F 302, an image processing unit 307 performs predetermined image processing on the received image data in accordance with instructions from the main controller 301. The main controller 301 then transmits the processed image data to the print engine unit 400 via a print engine I / F 304.

[0025] The recording device 100 may acquire image data from a connected external storage device (such as a USB memory stick). The operation panel 303 (same as the operation panel 101 in FIG. 1) is a mechanism that allows the user to input and output data to and from the recording device, and is specifically a touch panel. The user can use the operation panel 303 to instruct printing and paper feed operations, set the print mode and sheet type, and check information about the recording device, but the user can also input the above-mentioned instructions using a mouse and keyboard connected to the recording device 100.

[0026] The print engine unit 400 has a print controller 402 configured by a CPU. The print controller 402 controls various mechanisms of the print engine unit 400 using RAM 404 as a work area in accordance with programs and various parameters stored in ROM 403. When various commands and image data are input via a controller I / F 401, the print controller 402 temporarily stores the input commands and image data in RAM 404. The print controller 402 causes an image processing controller 405 to convert the stored image data into print data so that the print head 102 can use it for printing operations. When the print data is generated, the print controller 402 causes the print head 102 to perform a printing operation based on the generated print data via a head I / F 406. At this time, the print controller 402 drives the paper feeder 103 and paper discharger 104 shown in FIG. 1 via a conveyance control unit 407 to convey a sheet P, which is a printing medium. Furthermore, the print controller 402 dries and cools the transported sheet P by driving the heaters and fans that constitute the drying device 105, the cooling device 107, and the cooling device 108 via the transport control unit 407. Furthermore, the transport control unit 407 can detect the transport amount of the sheet P using an encoder provided on the transport roller. In accordance with instructions from the print controller 402, a recording operation is performed by the recording head 102 in conjunction with the transport operation of the sheet P, and printing processing is performed.

[0027] The print head 102 is configured to be movable up and down, and is lowered when performing printing processing, but raised during maintenance, etc. A head carriage control unit 408 changes the position of the print head 102 up (or down) depending on the operating state of the printing device 100, such as the maintenance state or the printing state. An ink supply control unit 409 controls the ink supply unit so that the pressure of ink supplied to the print head 102 falls within an appropriate range. When performing maintenance operations on the print head 102, a maintenance control unit 410 moves a maintenance unit below the raised print head 102 and controls maintenance operations for the print head 102, such as capping and wiping.

[0028] The scanner control unit 411 controls the scanner device 106. Specifically, for example, when the image data to be recorded is a test pattern for calculating various correction values, the print controller 402 instructs the conveyance control unit 407 to slow down the conveyance speed of the sheet P. The scanner device 106 then receives an instruction from the print controller 402 as to when to read the test pattern recorded on the sheet P, and reads the test pattern at the specified timing. The recorded image acquired by the reading is stored in the RAM 404. The print controller 402 then executes a process of calculating various correction values using the stored recorded image. The print controller 402 passes the calculated correction values to the image processing controller 405, and the correction values are reflected in subsequent recording operations.

[0029] Furthermore, for example, when reading roll paper that has not yet undergone a recording operation for detecting the paper width by detecting the sheet edge, the print controller 402 instructs the conveyance control unit 407 to change the conveyance speed of the sheet P to a predetermined conveyance speed. This predetermined conveyance speed is used to change the shape of the sheet P near the scanner device 106 into a shape suitable for paper width detection. The scanner device 106 then receives a read timing instruction from the print controller 402 and reads the sheet P at that timing. The recorded image obtained by the read is saved in the RAM 404. The print controller 402 (determination unit) then executes a paper width detection process using the saved read image, and sends the paper width parameters obtained by the paper width detection process to the controller unit 300 via the controller I / F 401. The sent paper width parameters are used for overall control of the recording device performed by the main controller 301.

[0030] 5A and 5B show flowcharts of various reading processes executed by the recording device 100. Fig. 5A is a flowchart of a reading process for detecting the paper width by detecting the edge of a non-transparent sheet. The following describes this reading process with reference to Fig. 5A.

[0031] In S501, the main controller 301 stores information indicating the type of sheet for which edge detection is to be performed (hereinafter referred to as sheet type information) in the RAM 305. Using this sheet type information, the main controller 301 can determine whether the target sheet is a transparent sheet or a non-transparent sheet. Here, it is assumed that, prior to this step, the user operates the operation panel 303 to set the sheet type of a non-transparent sheet, thereby inputting the sheet type information of the non-transparent sheet into the controller unit 300. It is also assumed that, as a result, the sheet type information of the non-transparent sheet is stored by this step.

[0032] In S502, the print controller 402 causes the scanner control unit 411 to raise the lifting unit 207, that is, move it upward (in the +Z direction), thereby pressing against the sheet P. Note that the print controller 402 performs each of the processes in S502 to S506 by loading a program stored in the ROM 402 into the RAM 404 in accordance with an instruction from the main controller 301, and executing the loaded program.

[0033] In S503, the print controller 402 drives the transport control unit 407 to rotate the multiple rollers 115. In this step, the multiple rollers 115 start to rotate, and transport of the sheet P begins. At this time, the print controller 402 drives the transport control unit 407 so that the rotation speed of the upstream transport roller 204 and the rotation speed of the downstream transport roller 205 are the same and the rotation direction of these rollers is forward. Note that, in this specification, "forward rotation" refers to a rotation direction in which the sheet P is transported in the forward direction of the X axis when the upstream transport roller 204 (or the downstream transport roller 205) rotates forward. Note that in this embodiment, each roller included in the multiple rollers 115 has the same shape. Therefore, as long as each roller rotates in the same direction at the same rotation speed, the transport speed of the sheet P at the position of each roller is the same.

[0034] In S504, the print controller 402 executes a reading process to read the sheet P using the scanner device 106.

[0035] In S505, the print controller 402 stops the transport control unit 407 and stops the rotation of the plurality of rollers 115 (including the upstream transport roller 204 and the downstream transport roller 205).

[0036] In S506, the print controller 402 causes the scanner control unit 411 to move the elevator unit 207 downward, that is, downward (-Z direction).

[0037] The read result is subjected to known image analysis, such as the Laplacian method or Canny method, which are edge detection algorithms that detect image edges along the Y direction, which is perpendicular to the transport direction (X direction). This image analysis will be described later with reference to Figure 6. The +X direction is called the first transport direction, and the -X direction is called the second transport direction.

[0038] [First embodiment] Hereinafter, as the reading process according to this embodiment, a reading process for detecting the paper width by detecting the edge of a transparent sheet will be described with reference to FIG. 5(b).

[0039] In S511, the main controller 301 stores the sheet type information in the RAM 305. Here, it is assumed that, prior to this step, the user operates the operation panel 303 to set the sheet type of a transparent sheet, thereby inputting the sheet type information of the transparent sheet into the controller unit 300. It is also assumed that, as a result, the sheet type information of the transparent sheet is stored by this step.

[0040] In S512, the print controller 402 drives the transport control unit 407 to rotate the plurality of rollers 115. In this step, the plurality of rollers 115 start to rotate, and transport of the sheet P begins. At this time, the print controller 402 drives the transport control unit 407 so that the rotation speed of the upstream transport rollers 204 and the rotation speed of the downstream transport rollers 205 are the same and the rotation direction of these rollers is forward. Note that the print controller 402 performs each of the processes in S512 to S519 by loading a program stored in the ROM 402 into the RAM 404 in accordance with instructions from the main controller 301 and executing the loaded program.

[0041] In S513, the print controller 402 drives the transport control unit 407 to reduce the rotation speed of the downstream transport roller 205 while maintaining the rotation speed of the upstream transport roller 204. This step causes the rotation speed of the upstream transport roller 204 to exceed the rotation speed of the downstream transport roller 205. Therefore, if this state continues, the length of the sheet P present on the transport path below the scanner device 106 increases, and the sheet P deforms (bends) between the scanner device 106 and the elevator unit 207, making it possible to change the distance between the sheet P and the scanner device 106. In this embodiment, the print controller 402 executes rotation control of the upstream transport roller and the downstream transport roller so that a first transport speed of the sheet P at the position of the upstream transport roller and a second transport speed of the sheet P at the position of the downstream transport roller are different.

[0042] In S514, the print controller 402 waits for a predetermined time. The predetermined time used in this step is the time required for the sheet P to be curved enough to enable paper width detection by sheet edge detection (i.e., for the sheet P to reach a sheet readable area for paper width detection by sheet edge detection). This predetermined time is set in advance; in other words, data on this predetermined time is stored in the ROM 403 in advance. This predetermined time is referred to as the "sheet curvature formation time." Note that if the print controller 402 waits for longer than the sheet curvature formation time, the sheet P will come into contact with the scanner device 106, so it is desirable to wait for the sheet curvature formation time.

[0043] In S515, the print controller 402 drives the transport control unit 407 to accelerate the rotation speed of the downstream transport roller 205, making the rotation speed equal to the rotation speed of the upstream transport roller 204. This step makes the rotation speed of the upstream transport roller 204 and the rotation speed of the downstream transport roller 205 equal, so that the curved state of the sheet P formed in S514 is maintained.

[0044] In S516, the print controller 402 executes a reading process to read the sheet P using the scanner device 106. At this time, the portion of the sheet P that is within the range of light emitted from the light source of the scanner device 106 is read by the scanner device 106. On the other hand, the portion of the sheet P that is outside that range is not read by the scanner device 106 because the light is directed toward the lifting / lowering unit 207 and is not reflected by the sheet P. Therefore, the color of the upper surface of the lifting / lowering unit 207 may be any color other than white, not limited to black.

[0045] In S517, the print controller 402 drives the transport control unit 407 to reduce the rotation speed of the upstream transport roller 204 while maintaining the rotation speed of the downstream transport roller 205. This step causes the rotation speed of the upstream transport roller 204 to fall below the rotation speed of the downstream transport roller 205. Therefore, if this state continues, the length of the sheet P present below the scanner device 106 will decrease, and the sheet P will deform (become flat) between the scanner device 106 and the lifting / lowering unit 207, making it possible to change the distance between the sheet P and the scanner device 106.

[0046] In S518, the print controller 402 waits until a predetermined time has elapsed. This predetermined time is referred to as the "sheet curvature elimination time." By waiting in this step, the sheet P between the scanner device 106 and the lifting / lowering unit 207 becomes flat.

[0047] In S519, the print controller 402 stops driving the transport control unit 407 and stops the rotation of the upstream transport roller 204 and the downstream transport roller 205. At this time, the sheet P is in a flat state between the scanner device 106 and the lifting unit 207.

[0048] 6 shows an example of the results of reading a transparent sheet in this embodiment. In this embodiment, an image of the sheet P that has stayed under the scanner device 106 during the reading time and an image of the area of the black plate provided on the upper surface of the lifting / lowering unit 207 are read. Area 601 indicates the area (referred to as the sheet reading area) where the sheet exists between the scanner device 106 and the black plate of the lifting / lowering unit 207. In this sheet reading area, light from the light source of the scanner device 106 reaches, and the reading result of the light being reflected by the sheet P is displayed.

[0049] On the other hand, area 602 indicates an area (hereinafter referred to as the elevator unit reading area) where no sheet exists between the scanner device 106 and the black plate of the elevator unit 207. Since light from the light source of the scanner device 106 does not reach this elevator unit reading area, the reading result appears black as shown in the figure.

[0050] The scan results obtained in S504 of FIG. 5 are subjected to well-known image analysis, such as the Laplacian or Canny edge detection algorithm, which detects image edges along the +Y direction perpendicular to the transport direction (+X direction), to determine whether each pixel is a black pixel or a non-black pixel. The print controller 402 (determination unit) then determines the Y-direction position where black pixels change to non-black pixels as the boundary between the presence or absence of a transparent sheet, and determines the position of the non-black pixel as one edge of the transparent sheet. Similarly, the print controller 402 determines the Y-direction position where non-black pixels change to black pixels as the boundary between the presence or absence of a transparent sheet, and determines the position of the non-black pixel as the other edge of the transparent sheet. The paper width of the sheet P can be detected by calculating the Y-direction distance between the two edges derived in this way.

[0051] As described above, in this embodiment, the transparent sheet P is moved within the range of light from the light source of the scanner device 106, and then read by the scanner device 106. This configuration makes it possible to read the difference between the presence or absence of the sheet P.

[0052] [Second embodiment] In the first embodiment, a configuration was described in which the downstream transport roller 205 is decelerated to create a speed difference with the upstream transport roller 204. In contrast, in the present embodiment, a configuration will be described in which the upstream transport roller 204 is accelerated to create a speed difference with the downstream transport roller 205. The transparent sheet reading process according to this embodiment will be described below with reference to FIG. 5(c).

[0053] In S521, the main controller 301 stores the sheet type information in the RAM 305. Here, it is assumed that, prior to this step, the user operates the operation panel 303 to set the sheet type of a transparent sheet, thereby inputting the sheet type information of the transparent sheet into the controller unit 300. It is also assumed that, as a result, the sheet type information of the transparent sheet is stored by this step.

[0054] In S522, the print controller 402 drives the transport control unit 407 to rotate the plurality of rollers 115 at a low speed. "Low speed" means a speed slower than the speed at which the plurality of rollers 115 start to rotate in the first embodiment (S512 in FIG. 5B). In this step, the plurality of rollers 115 start to rotate, and transport of the sheet P begins. At this time, the print controller 402 drives the transport control unit 407 so that the rotation speed of the upstream transport rollers 204 and the rotation speed of the downstream transport rollers 205 are the same and the rotation direction of these rollers is forward. Note that the print controller 402 performs each of the processes in S522 to S529 by loading a program stored in the ROM 402 into the RAM 404 in accordance with instructions from the main controller 301 and executing the loaded program.

[0055] In S523, the print controller 402 drives the transport control unit 407 to accelerate the rotation speed of the upstream transport roller 204 while maintaining the rotation speed of the downstream transport roller 205. This step causes the rotation speed of the upstream transport roller 204 to exceed the rotation speed of the downstream transport roller 205. Therefore, if this state continues, the length of the sheet P present below the scanner device 106 increases, and the sheet P deforms (bends) between the scanner device 106 and the lifting / lowering unit 207, so that the distance between the sheet P and the scanner device 106 can be changed.

[0056] In S524, the print controller 402 waits for a predetermined time. The predetermined time used in this step is the time required for the sheet P to be curved to an extent that paper width detection by sheet edge detection is possible (i.e., the sheet P has reached a sheet readable area for paper width detection by sheet edge detection). This predetermined time is set in advance; in other words, data on this predetermined time is stored in the ROM 403 in advance. This predetermined time is referred to as the "sheet curvature formation time." Note that if the print controller 402 waits for longer than the sheet curvature formation time, the sheet P will come into contact with the scanner device 106, so it is desirable to wait for the sheet curvature formation time.

[0057] In S525, the print controller 402 drives the conveyance control unit 407 to reduce the rotation speed of the upstream conveyance roller 204, and make the rotation speed equal to the rotation speed of the downstream conveyance roller 205. By this step, the rotation speed of the upstream conveyance roller 204 and the rotation speed of the downstream conveyance roller 205 become equal, so that the curved state of the sheet P formed in S524 is maintained.

[0058] In S526, the print controller 402 executes a reading process to read the sheet P using the scanner device 106. At this time, the portion of the sheet P that is within the range of light emitted from the light source of the scanner device 106 is read by the scanner device 106. On the other hand, the portion of the sheet P that is outside that range is not read by the scanner device 106 because the light is directed toward the lifting / lowering unit 207 and is not reflected by the sheet P. Therefore, the color of the upper surface of the lifting / lowering unit 207 may be any color other than white, not limited to black.

[0059] In S527, the print controller 402 drives the transport control unit 407 to accelerate the rotation speed of the downstream transport roller 205 while maintaining the rotation speed of the upstream transport roller 204. This step causes the rotation speed of the upstream transport roller 204 to become lower than the rotation speed of the downstream transport roller 205. Therefore, if this state continues, the length of the sheet P present below the scanner device 106 will decrease, and the sheet P will deform (become flat) between the scanner device 106 and the lifting / lowering unit 207, making it possible to change the distance between the sheet P and the scanner device 106.

[0060] In S528, the print controller 402 waits until a predetermined time has elapsed. This predetermined time is referred to as the "sheet curvature elimination time." By waiting in this step, the sheet P between the scanner device 106 and the lifting / lowering unit 207 becomes flat.

[0061] In S529, the print controller 402 stops driving the transport control unit 407 and stops the rotation of the upstream transport roller 204 and the downstream transport roller 205. At this time, the sheet P is in a flat state between the scanner device 106 and the lifting unit 207.

[0062] As described above, in this embodiment, the transparent sheet P is moved within the range of light from the light source of the scanner device 106, and then read by the scanner device 106. This configuration makes it possible to read the difference between the presence or absence of the sheet P.

[0063] [Third embodiment] In the first embodiment, a configuration was described in which the downstream transport roller 205 is decelerated to create a speed difference with the upstream transport roller 204. In contrast, in the present embodiment, a configuration will be described in which the downstream transport roller 205 is stopped to create a speed difference with the upstream transport roller 204. The transparent sheet reading process according to this embodiment will be described below with reference to FIG. 5(d).

[0064] In S531, the main controller 301 stores the sheet type information in the RAM 305. Here, it is assumed that, prior to this step, the user operates the operation panel 303 to set the sheet type of a transparent sheet, thereby inputting the sheet type information of the transparent sheet into the controller unit 300. It is also assumed that, as a result, the sheet type information of the transparent sheet is stored by this step.

[0065] In S532, the print controller 402 drives the transport control unit 407 to rotate the plurality of rollers 115. In this step, the plurality of rollers 115 start to rotate, and transport of the sheet P begins. At this time, the print controller 402 drives the transport control unit 407 so that the rotation speed of the upstream transport rollers 204 and the rotation speed of the downstream transport rollers 205 are the same and the rotation direction of these rollers is forward. Note that the print controller 402 performs each of the processes in S532 to S539 by loading a program stored in the ROM 402 into the RAM 404 in accordance with instructions from the main controller 301 and executing the loaded program.

[0066] In S533, the print controller 402 drives the transport control unit 407 to stop the rotation of the downstream transport roller 205 while maintaining the rotation speed of the upstream transport roller 204. This step causes the rotation speed of the upstream transport roller 204 to exceed the rotation speed of the downstream transport roller 205. Therefore, if this state continues, the length of the sheet P present below the scanner device 106 increases, and the sheet P deforms (bends) between the scanner device 106 and the lifting / lowering unit 207, so that the distance between the sheet P and the scanner device 106 can be changed.

[0067] In S534, the print controller 402 waits for a predetermined time. The predetermined time used in this step is the time required for the sheet P to be curved enough to enable paper width detection by sheet edge detection (i.e., for the sheet P to reach a sheet readable area for paper width detection by sheet edge detection). This predetermined time is set in advance; in other words, data on this predetermined time is stored in the ROM 403 in advance. This predetermined time is referred to as the "sheet curvature formation time." Note that if the print controller 402 waits for longer than the sheet curvature formation time, the sheet P will come into contact with the scanner device 106, so it is desirable to wait for the sheet curvature formation time.

[0068] In S535, the print controller 402 drives the transport control unit 407 to stop the rotation of the upstream transport roller 204. This step stops the upstream transport roller 204 and the downstream transport roller 205, so the curved state of the sheet P formed in S534 is maintained.

[0069] In S536, the print controller 402 executes a reading process to read the sheet P using the scanner device 106. At this time, the portion of the sheet P that is within the range of light emitted from the light source of the scanner device 106 is read by the scanner device 106. On the other hand, the portion of the sheet P that is outside that range is not read by the scanner device 106 because the light is directed toward the lifting / lowering unit 207 and is not reflected by the sheet P. Therefore, the color of the upper surface of the lifting / lowering unit 207 may be any color other than white, not limited to black.

[0070] In S537, the print controller 402 drives the transport control unit 407 to rotate the upstream transport roller 204 in the reverse direction. When the upstream transport roller 204 starts to rotate in this step, the length of the sheet P present below the scanner device 106 decreases because the rotation of the downstream transport roller 205 has stopped. In other words, the sheet P is deformed (flattened) between the scanner device 106 and the lifting / lowering unit 207. Note that in this specification, "reverse" refers to a rotation direction in which the sheet P is transported in the negative direction of the X axis when the upstream transport roller 204 (or downstream transport roller 205) rotates in the reverse direction.

[0071] In S538, the print controller 402 waits until a predetermined time has elapsed. This predetermined time is referred to as the "sheet curvature elimination time." By waiting in this step, the sheet P between the scanner device 106 and the lifting / lowering unit 207 becomes flat.

[0072] In S539, the print controller 402 stops driving the transport control unit 407 and stops the rotation of the upstream transport roller 204 and the downstream transport roller 205. At this time, the sheet P is in a flat state between the scanner device 106 and the lifting unit 207.

[0073] As described above, in this embodiment, the transparent sheet P is moved within the range of light from the light source of the scanner device 106, and then read by the scanner device 106. This configuration makes it possible to read the difference between the presence or absence of the sheet P.

[0074] The present disclosure can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0075] [Technical Features of the Present Disclosure] The present disclosure includes the following configurations.

[0076] (Configuration 1) A sheet detection device having a conveying means for conveying a sheet in a predetermined first conveying direction, a reading means for reading the sheet conveyed by the conveying means, and a control means for controlling at least the conveying means and the reading means, wherein the conveying means includes a plurality of rollers, the plurality of rollers including a first roller located upstream of the reading means and closest to the reading means in the first conveying direction, and a second roller located downstream of the reading means and closest to the reading means, and the control means performs rotation control of the first roller and the second roller so as to make a first conveying speed of the sheet at the position of the first roller different from a second conveying speed of the sheet at the position of the second roller before the sheet is read by the reading means. (Configuration 2) The sheet detecting device according to configuration 1, wherein the sheet is a transparent sheet or a non-transparent sheet. (Configuration 3) The sheet detecting device according to configuration 1 or 2, characterized in that the control means executes the rotation control when the sheet is a transparent sheet. (Configuration 4) Each of the plurality of rollers has the same shape, The sheet detecting device of any one of configurations 1 to 3, characterized in that the rotation control of the control means causes a first rotation speed for the first roller to be faster than a second rotation speed for the second roller. (Configuration 5) The sheet detecting device according to any one of Configurations 1 to 4, wherein the control means controls the rotation by reducing the second rotation speed while maintaining the first rotation speed. (Configuration 6) The sheet detecting device according to any one of Configurations 1 to 5, wherein the control means performs the rotation control by accelerating the first rotation speed while maintaining the second rotation speed. (Configuration 7) The sheet detecting device according to any one of configurations 1 to 6, wherein the control means stops the second rotation speed as the rotation control. (Configuration 8) The sheet detecting device according to any one of configurations 1 to 7, wherein the control means waits for a predetermined time after executing the rotation control. (Configuration 9) The sheet detecting device according to any one of configurations 1 to 8, wherein the control means waits for a predetermined time, thereby causing the sheet to curve. (Configuration 10) A sheet detection device according to any one of configurations 1 to 9, further comprising a transport path along which the sheet is transported, and the reading means is transported along the transport path and reads the sheet below the reading means. (Configuration 11) A sheet detection device according to any one of configurations 1 to 10, further comprising a detection means for analyzing the reading results by the reading means and detecting the edges of the image, and a detection means for detecting the paper width of the sheet based on the detection results by the detection means. (Control Method 1) A control method for a sheet detection device having a conveying means for conveying a sheet in a predetermined first conveying direction, a reading means for reading the sheet conveyed by the conveying means, and a control means for controlling at least the conveying means and the reading means, wherein the conveying means includes a plurality of rollers, the plurality of rollers including a first roller located upstream of the reading means and closest to the reading means in the first conveying direction, and a second roller located downstream of the reading means and closest to the reading means, and the control method includes a step in which, before the sheet is read by the reading means, the control means performs rotation control of the first roller and the second roller so as to make a first conveying speed of the sheet at the position of the first roller different from a second conveying speed of the sheet at the position of the second roller. (Program 1) A program for causing a computer to execute a control method for a sheet detection device having a conveying means for conveying a sheet in a predetermined first conveying direction, a reading means for reading the sheet conveyed by the conveying means, and a control means for controlling at least the conveying means and the reading means, wherein the conveying means includes a plurality of rollers, the plurality of rollers including a first roller located upstream of the reading means and closest to the reading means in the first conveying direction, and a second roller located downstream of the reading means and closest to the reading means, and the control means has a step of performing rotation control of the first roller and the second roller so as to make a first conveying speed of the sheet at the position of the first roller different from a second conveying speed of the sheet at the position of the second roller before the sheet is read by the reading means. [Explanation of symbols]

[0077] 100 Recording device 106 Scanner Device 115 Roller 202A Sensor 202B Sensor 204 Upstream transport roller 205 Downstream transport roller 402 Print Controller

Claims

1. a conveying means for conveying the sheet in a predetermined first conveying direction; a reading means for reading the sheet conveyed by the conveying means; a control means for controlling at least the transport means and the reading means; A sheet detecting device having: the conveying means includes a plurality of rollers; the plurality of rollers include a first roller located upstream of the reading unit and closest to the reading unit in the first transport direction, and a second roller located downstream of the reading unit and closest to the reading unit, the control means controls the rotation of the first roller and the second roller so that a first conveying speed of the sheet at the position of the first roller and a second conveying speed of the sheet at the position of the second roller are different from each other before the sheet is read by the reading means. A sheet detecting device characterized by:

2. The sheet is a transparent sheet or a non-transparent sheet.

2. The sheet detecting device according to claim 1, wherein the sheet detecting device detects a position of the sheet.

3. When the sheet is a transparent sheet, the control means executes the rotation control.

3. The sheet detecting device according to claim 2.

4. Each of the plurality of rollers has the same shape, The rotation control by the control means causes a first rotation speed for the first roller to be faster than a second rotation speed for the second roller.

4. The sheet detecting device according to claim 3.

5. the control means controls the rotation by maintaining the first rotation speed while reducing the second rotation speed.

5. The sheet detecting device according to claim 4.

6. the control means accelerates the first rotation speed while maintaining the second rotation speed as the rotation control.

5. The sheet detecting device according to claim 4.

7. The control means stops the second rotation speed as the rotation control.

5. The sheet detecting device according to claim 4.

8. the control means waits for a predetermined time after executing the rotation control.

8. The sheet detecting device according to claim 5, wherein the sheet detecting device is a sheet detecting device.

9. The control means waits for a predetermined time, thereby causing the sheet to curve.

9. The sheet detecting device according to claim 8.

10. The sheet conveying device further includes a conveying path along which the sheet is conveyed, the reading means is transported along the transport path and reads the sheet below the reading means; 8. The sheet detecting device according to claim 1, wherein the sheet detecting device is a sheet detecting device.

11. a detection means for analyzing the read result by the reading means and detecting edges of the image; a detection means for detecting the width of the sheet based on the detection result by the detection means; Further comprising: The sheet detecting device according to claim 10 .

12. a conveying means for conveying the sheet in a predetermined first conveying direction; a reading means for reading the sheet conveyed by the conveying means; a control means for controlling at least the transport means and the reading means; A method for controlling a sheet detection device having the conveying means includes a plurality of rollers; the plurality of rollers include a first roller located upstream of the reading unit and closest to the reading unit in the first transport direction, and a second roller located downstream of the reading unit and closest to the reading unit, the control means, before the reading means reads the sheet, performing rotation control of the first roller and the second roller so as to make a first conveying speed of the sheet at the position of the first roller different from a second conveying speed of the sheet at the position of the second roller; A control method comprising:

13. A program for causing a computer to execute the method according to claim 12.

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