Image reader

Abstract

To provide an image reading device that does not increase a size of a structure even in which a position reference member is read by using a reading unit.SOLUTION: An image reading device according to the present invention includes: a first glass configured to enable an original document to be placed on a front surface side thereof; an adjacent portion adjacent to the first glass; a reading unit that is capable of being in contact with at least one of the adjacent portion and the first glass and is configured to read, from a back surface side of the first glass, the original document placed on the first glass by using a sensor while moving from the adjacent portion side in a movement direction; and a position reference portion that is disposed on the front surface side of the first glass and serves as a reference of a position of the reading unit in the movement direction. When the position reference portion is read by the reading unit, the reading unit is in contact with the adjacent portion and the first glass.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an image reading device. [Background technology]

[0002] There is known an image reading device that can read an original while moving a reading unit under a first glass, and read a conveyed original while stopping the reading unit under a second glass. When reading an original while moving the reading unit, it is desirable that the reading unit can move stably. In Patent Document 1, a step between the first glass, the second glass, and a separating member that separates the original from the second glass between the first glass and the second glass is an issue. In order to eliminate the step, a guide member that spans both the second glass and the separating member is used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-106854 A Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, when the reading unit reads a white reference member for calibrating the output from the sensor, the reading unit abuts only against the first glass. However, there is no disclosure regarding a position reference member for calibrating the position of the document relative to the reading unit. If the reading unit abuts only against the first glass when reading the position reference member, the image reading device becomes large. An object of the present invention is to provide an image reading device that does not have a large configuration even when the reading unit reads the position reference member. [Means for solving the problem]

[0005] The image reading device of the present invention includes a first glass on which an original is placed on its front side, an adjacent portion adjacent to the first glass, a reading unit that can abut against at least one of the adjacent portion or the first glass and that reads the original placed on the first glass from the back side of the first glass using a sensor while moving in a movement direction from the adjacent portion side, and a position reference portion that is arranged on the front side of the first glass and serves as a reference for the position of the reading unit in the movement direction, and is characterized in that when the position reference portion is read by the reading unit, the reading unit abuts against the adjacent portion and the first glass. Effect of the Invention

[0006] According to the present invention, it is possible to provide an image reading device that does not have a large configuration even when a position reference member is read by a reading unit. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a perspective view of the image reading device when the document transport unit is open. [Diagram 2] 4 is a cross-sectional view of the image reading device when the document transport unit is closed. FIG. [Diagram 3] 2A and 2B are a top view and a cross-sectional view of a scanner unit that reads a placed document. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. 2 is a top view showing the internal configuration of the scanner unit. [Figure 7] FIG. 2 is a cross-sectional view of the periphery of the image sensor. [Figure 8] FIG. 2 is a block diagram showing an electrical circuit configuration. [Figure 9] 4 is a cross-sectional view showing a position where a reading unit performs various processes. FIG. [Figure 10] 4 is a cross-sectional view showing the position of the reading unit from when the power is turned on until when an image is read. FIG. [Figure 11]4 is a cross-sectional view showing the position of the reading unit from when the power is turned on until when an image is read. FIG. [Figure 12] FIG. 11 is a diagram showing the distribution of brightness levels of an image obtained by reading a reference member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment does not limit the present invention, and not all of the combinations of features described in the present embodiment are necessarily essential to the solution of the present invention. Note that the same configurations will be described with the same reference numerals. Also, the relative arrangements, shapes, etc. of the components described in the embodiments are merely examples, and are not intended to limit the scope of the present invention to only those. Therefore, the present invention can be embodied in various other forms, and various omissions, substitutions, combinations, and modifications can be made within the scope of the invention.

[0009] The image reading device of the present invention can be applied to a flatbed scanner device, or a copying machine, a facsimile, a multifunction machine, etc., which is a combination of a flatbed scanner device and a printing device.

[0010] [Embodiment] <Image reader> The image reading device 100 of this embodiment is a multifunction machine 1 combined with a printing device 400, which is an inkjet printer. FIG. 1 shows a state in which the document transport unit 300 is opened with respect to a document table glass for placing a document of the scanner unit 200. The image reading device 100 is composed of the image reading unit 200 (scanner unit) and a document transport unit 300 (ADF: Auto Document Feeder) arranged on the image reading unit 200. The image reading unit 200 is arranged on the printing device 400. The printing device 400 can transport a sheet from a cassette to the printing unit and record an image on the sheet in the printing unit. The printing unit is an inkjet type that ejects ink from a print head onto the sheet, but may be an electrophotographic type. The multifunction machine 1 can read an image of a document with the image reading device 100 and record the read image on a sheet with the printing device 400.

[0011] 2 is a cross-sectional view of the image reading device 100 in the XZ plane when the document transport unit 300 is closed. The document transport unit 300 is configured with a document transport path 311 (indicated by a thick solid arrow). A part of the document transport path 311 uses a part of the glass frame unit 201 of the scanner unit 200.

[0012] The image reading device 100 of this embodiment has two document reading methods: a fixed document reading method in which the document is fixed and read, and a document conveying reading method in which the document is conveyed and read. The reading unit 207 that reads the document can read an image of one line in the main scanning direction (Y direction) with the image sensor 206. In the fixed document reading method, the document is placed on the front side of the document table glass 202, and the entire document is read by moving the reading unit 207 in the sub-scanning direction (moving direction, X direction) that intersects with the main scanning direction. On the other hand, in the document conveying reading method, the reading unit 207 is placed at a predetermined position (ADF position) under the ADF glass 203, and the document is read while being conveyed by the document conveying unit 300. In FIG. 2, the reading unit 207 in the scanner unit 200 is stopped at the ADF position to read the document 310 conveyed by the document conveying unit 300.

[0013] The document transport section 300 includes a document tray 301 on which documents are placed, a document transport mechanism, and a document discharge section 303. The document transport mechanism is the entire mechanism that transports documents from a pickup roller 304 to a discharge roller 309. The configuration of the document transport mechanism will be described below in order starting from the upstream side of document transport.

[0014] The document 310 placed on the document tray 301 is conveyed toward the separation roller 305 by the pickup roller 304 of the document conveying mechanism, and then conveyed one by one by the separation roller 305 and the separation pad 306 to the downstream conveying roller 307. The document 310 is then conveyed by the conveying roller 307 to the downstream ADF glass 203. When passing through the ADF glass 203, the pressing plate 308 presses the document 310 to bring the document 310 into contact with the ADF glass 203. At this time, the image of the document 310 is read by the image sensor 206. The document 310 that has passed through the ADF glass 203 is separated from the ADF glass 203 by the document separating surface 227 on the downstream side of the ADF glass 203, and is discharged to the document discharge section 303 by the discharge roller 309. The adjacent section 205 is a part of the glass frame 204, and the document separating surface 227 is formed on the upper side. The ADF glass 203 is supported from below by a glass frame 204. In addition, various document detection sensors (not shown) are arranged in the document transport mechanism. The document detection sensors detect the passage of the leading and trailing ends of a document, and are used to control the timing of document reading by an image sensor 206.

[0015] The configuration of the scanner unit 200 of the image reading device 100 will be described below with reference to FIGS.

[0016] FIG. 3 is a top view and a cross-sectional view of the scanner unit 200 when the document transport unit 300 is removed. FIG. 3(a) shows (1) the entire glass frame unit 201, (2) an AA cross-sectional view, and (3) a BB cross-sectional view. FIG. 3(b) is an enlarged view of the cross-section C around the adjacent unit 205 in FIG. 3(a)(2). The glass frame unit 201 is composed of a document table glass 202 for placing a document, an ADF glass 203 for reading the transported document, and a glass frame 204 for holding these glasses. The glass frame 204 also has a document separation surface 227 between the document table glass 202 and the ADF glass 203, which is a part of the document transport path. The adjacent unit 205 with the document separation surface 227 has a glass frame abutment portion 228 that abuts against the side of the document table glass 202, and a document abutment portion 226 that serves as a reference for the position of the document. A glass frame guide surface 233 that becomes part of paths D1 and D2 for the rollers of the reading unit 207 is provided on the rear surface side of the adjacent portion 205. The ADF glass 203 is held by the glass frame guide surface 233. This glass frame guide surface 233 is at the same height as a rear surface 234 of the original table glass so that the reading unit 207 can move stably. Note that a step is generated between the chamfered portion 229 of the original table glass 202 and the rear surface of the adjacent portion 205.

[0017] FIG. 4 is a rear view of the glass frame unit 201. The platen glass 202 is abutted against a glass frame abutment portion 228 of the glass frame 204, and the position in the X direction is determined. The reference member 224 is disposed on the front side (the rear side in this figure) of the platen glass 202 on which the platen glass 202 is placed, below the platen separation surface 227 of the adjacent portion 205 and the flat surface 225 continuing from the platen separation surface 227. The reference member 224 is disposed between the ADF glass 203 and the platen reading area 237 for reading the placed platen. The reference member 224 also has a white reference portion 224W that is white for performing shading correction of the image sensor 206, and a black portion 224B that is black and serves as a position reference in the sub-scanning direction of the image sensor 206. The white reference portion 224W is adjacent to the black portion 224B. However, white reference portion 224W for performing shading correction is the area on the document abutment portion 226 side from the two-dot chain line in the figure. Also, the width of white reference portion 224W is wider than the width of image sensor 206 in the main scanning direction. Therefore, it can be imaged by all elements of image sensor 206. On the other hand, black portion 224B is a partial area of ​​image sensor 206 in the main scanning direction. Black portion 224B is closer to ADF glass 203 than white reference portion 224W in the sub-scanning direction.

[0018] FIG. 5 shows a reading unit 207 that reads an image of a document. (a) is a top view of the reading unit 207, (b) is a view of the reading unit 207 from the back side, and (c) is a view showing a roller unit. The reading unit 207 is composed of an image sensor 206, a sensor holder 217, a slider 218, and a drive unit for moving the reading unit 207. The drive unit is composed of a motor 220 as a drive source, and a speed reduction mechanism and a drive gear 219 (not shown) that transmit the driving force of the motor 220. At both ends of the image sensor 206 in the main scanning direction, a roller unit 211 and a roller unit 212 that guarantee the focal distance with the document are arranged. In each of the roller units 211 and 212, rollers 213 and 214 and rollers 215 and 216 that are abutting portions that abut against the adjacent portion or the document table glass 202 are arranged rotatably in the sub-scanning direction. In addition, a pressure spring 232 is disposed between the image sensor 206 and the sensor holder 217, and the image sensor 206 is constantly pressed against the rear surface of the platen glass 202. When the reading unit 207 moves in the sub-scanning direction, these rollers roll on the dotted line D1 or D2 of the glass frame unit 201 shown in FIG.

[0019] FIG. 6 is a top view showing the internal configuration of the scanner unit. The arrangement of the reading unit 207 and the base frame 223 of the scanner unit 200 is shown. A guide rail 221 with its longitudinal direction as the sub-scanning direction and a rack 222 adjacent to the guide rail 221 are arranged in the approximate center of the base frame 223 in the main scanning direction. In the reading unit 207, the slider 218 is arranged on the guide rail 221 so as to be slidable in the sub-scanning direction, and the drive gear 219 is arranged to mesh with the rack 222. Therefore, when a driving input is input to the motor 220, the drive gear 219 meshing with the rack 222 rotates, and the reading unit 207 can reciprocate along the guide rail in the sub-scanning direction or the return direction. The driving unit may be a belt-driven type arranged on the base frame 223 and transmitting the driving force by a belt.

[0020] Here, the electrical configuration of the reading unit 207 will be described with reference to Figs. 7 and 8. Fig. 7 is a cross-sectional view of the periphery of the image sensor 206. The image sensor 206 incorporates therein three color light emitting elements 102 (LEDs), a rod lens array 209, and a light receiving element 101 having a plurality of elements aligned in the main scanning direction. Light irradiated onto the document from the LEDs 102 is reflected by the document surface, and this reflected light passes through the rod lens array 209 to form an image on the light receiving element 101. The image sensor 206 sequentially switches the three color LEDs 102 on and reads the reflected light from the document for each color, thereby making it possible to obtain the intensity of the reflected light for each color.

[0021] 8 is a block diagram showing the configuration of a control circuit for the reading unit 207. The image sensor 206 is integrated with three-color LEDs 102 that serve as light sources. The control unit 115 causes the reading unit 207 to move the image sensor 206 in the sub-scanning direction below the platen glass 202. At the same time, the LED drive circuit 103 switches and lights up the LEDs 102 of each color for each line, thereby sequentially reading RGB color images. The signal output from the image sensor 206 is amplified by an amplifier (AMP) 104, and then converted by an A / D converter 105 into, for example, an 8-bit digital output.

[0022] The shading RAM 106 stores data for shading correction, which is obtained by performing arithmetic processing on data obtained by reading the white reference portion 224W. The shading correction circuit 107 performs shading correction on the image data read by the image sensor 206 based on the data stored in the shading RAM 106. The peak detection circuit 108 is a circuit that detects the peak value in the read image data for each line, and is used to detect the reference position of the image sensor 206. The gamma conversion circuit 109 performs gamma conversion on the read image data according to a gamma curve that is preset by an external device 113 such as a computer. The buffer RAM 110 is a memory that temporarily stores image data in order to match the timing of the actual reading operation and the communication with the external device 113. The packing / buffer RAM control circuit 111 performs packing processing according to an image output mode (binary, 4-bit multi-value, 8-bit multi-value, 24-bit multi-value, etc.) that is preset by the external device 113. Furthermore, it performs a process of writing the data into the buffer RAM 110, and a process of transferring the image data from the buffer RAM 110 to the interface circuit 112 and outputting it. The interface circuit 112 receives control signals and outputs image signals between the external device 113. The control unit 115 has a CPU, a ROM 115a that stores processing procedures, and a working RAM 115b, and controls each unit according to the procedures of the program stored in the ROM 115a. The timing signal generating circuit 114 divides the output of an oscillator 116, which is a crystal oscillator, according to the settings of the control unit 115, and generates various timing signals that serve as the basis for operation.

[0023] <Reading unit position> Each operation of the reading unit 207 and the position of the reading unit 207 at that time will be described. First, when the user turns on the power, the control unit 115 starts initialization of the reading unit 207. When the initialization is completed, the reading unit 207 moves in the sub-scanning direction to detect a reference mark and determine the reference position of the reading unit 207. The reference position that serves as the reference for the position in the sub-scanning direction is the boundary between the black part 224B and the white reference part 224W. That is, the boundary between the black part 224B and the white reference part 224W is present as the position reference part, and the position reference part functions as a reference mark. The RAM 115b stores the detected reference mark and the determined reference position. Next, the reading unit 207 is moved in the sub-scanning direction based on the reference position to perform shading processing. After that, the reading unit 207 waits until it receives a command to read an image at the home position.

[0024] 9 to 11, the positions and operations of reading unit 207 from initialization to standby will be described. Alphabet characters a to f in Fig. 9 indicate the position of the optical center (dashed line in Fig. 9) of rod lens array 209 when performing each operation of reading unit 207. They are a: position before power is turned on, b: initialization position, c: reference position, d: home position (shading start position), e: shading end position, and f: document reading start position.

[0025] The position of the reading unit 207 before power is turned on is denoted as a for convenience, but it is an arbitrary position. When power is turned on, the RAM 115b does not have current position information of the reading unit 207, so the control unit 115 starts the initialization operation of the reading unit 207. First, the reading unit 207 moves in the return direction opposite to the sub-scanning direction in which the reading unit 207 moves when reading an image. Then, the sensor holder abutment portion 231 of the sensor holder 217 abuts against the inner wall 230 of the base frame 223, and the reading unit 207 stops. When the reading unit 207 cannot move due to the inner wall 230, the current supplied to the motor 220 that drives the reading unit 207 increases. When the supplied current exceeds a threshold value, the control unit 115 can determine that the reading unit 207 has abutted against the inner wall 230 of the base frame 223. The position of the reading unit 207 at this time is the initialization position b (FIG. 10(a)). Further, the roller 215 contacts a glass frame guide surface 233, and the roller 216 contacts a rear surface 234 of the document table glass.

[0026] Next, the reading unit 207 starts moving in the sub-scanning direction to detect the position reference portion of the boundary between the white reference portion 224W and the black portion 224B of the reference member 224. At this time, the roller 215 abuts against the glass frame guide surface 233 and moves while rotating. Meanwhile, the roller 216 abuts against the rear surface 234 of the document table glass and moves while rotating. While maintaining the abutment state of these rollers, the reading unit 207 reaches a position where the position reference portion is read (FIG. 10(b)). At this time, the roller 215 abuts against the rear surface of the adjacent portion 205, and the roller 216 abuts against the rear surface 234 of the document table glass. The rear surface of the adjacent portion 205 and the rear surface 234 of the document table glass are designed to be at the same height. However, in reality, a step occurs due to the tolerance of the parts. The posture of the reading unit 207 when reading the position reference portion is not the ideal posture in which the roller 215 and the roller 216 abut against the same rear surface 234 of the document table glass as shown in FIG. 10(c). However, the image sensor 206 has a wide dynamic range. For example, it reads continuous changes in tone from black to white with an 8-bit resolution of 0 to 255. On the other hand, the position reference portion is detected in the monochrome binarization mode (1 bit) of the image sensor 206. Therefore, even if the attitude of the image sensor 206 is tilted due to component precision, the wide dynamic range does not affect it to the extent that it causes an error in binarization discrimination.

[0027] At the reference position c, the roller 215 maintains a state of being in contact with the back surface of the adjacent portion 205, and is located at a position separated from the step between the glass frame abutting surface 228 and the beveled portion 229 of the platen glass surface. As shown in FIG. 9(b), the distance from the position reference portion (reference position c) to the boundary (step) between the platen glass 202 and the glass frame abutting portion 228 is L1. Note that the length of the black portion 224B in the sub-scanning direction is shorter than L1. Also, as shown in FIG. 9(a), the distance from the optical center of the rod lens array to the apex of the roller 215 is L4. Since L1 is shorter than L4, the relationship L1 < L4 holds. Therefore, the reading unit 207 can read the reference position c in a region not affected by the step. Also, the roller 215 is not on the side of the platen glass 202 beyond the beveled portion 229 of the platen glass surface. Therefore, the operating range from the inner wall 230 of the base frame 223 of the reading unit 207 becomes shorter. Also, since the platen glass 202 can be made shorter, the device width in the sub-scanning direction becomes smaller. That is, in the case of a configuration in which the roller 215 abuts on the back surface 234 of the platen glass at the position where the reference mark is read (FIG. 10(b)), the movable range of the reading unit 207 becomes longer. Also, since the platen glass 202 becomes longer, the device size becomes larger.

[0028] The position that has moved a specified amount in the sub-scanning direction from the reference position c is the home position d (FIG. 10(c)). This home position d is also the start position of the reading operation for shading processing. When moving from the reference position c to the home position d, the roller 215 crosses the step between the glass frame abutting portion 228 and the beveled portion 229 of the platen glass surface and abuts on the same back surface 234 of the platen glass as the roller 216. The distance from the reference position c to the end of the white reference portion 224W in the sub-scanning direction is longer than the distance L4 from the optical center of the rod lens array to the apex of the roller 215. Note that the reading unit 207 waits at the home position d until the reading is started.

[0029] Before reading the image of the document placed on the document glass 202, the control unit 115 performs shading processing of the image sensor 206. The white reference portion 224W is read from the home position d, which is the start position of the shading, in the sub-scanning direction at a predetermined reading resolution up to a predetermined length, and the shading processing ends (FIG. 11(a)). After the shading processing ends, the image sensor returns to the home position d again. In this shading processing, the rollers 215 and 216 of the reading unit 207 maintain a state of contact with the rear surface 234 of the document glass. Therefore, the shading processing is performed in the same posture as when the image is read, and the similarity of the optical system is maintained. Therefore, the shading correction is performed with high accuracy. The reading of the image starts from the document reading start position f, where the reading speed is accelerated from the home position d in the sub-scanning direction and a stable reading speed is reached (FIG. 11(b)).

[0030] <Lighting direction> Here, the relationship between the arrangement of the white reference portion 224W and the black portion 224B of the reference member 224 and the illumination direction in the image sensor 206 will be described. Fig. 12 is a graph showing the brightness level of the image of the reference member 224 read by the image sensor 206. Fig. 12 shows the distribution of brightness levels in the sub-scanning direction corresponding to the E-E cross section in Fig. 4. The vertical axis represents the brightness level, and the horizontal axis represents the distance in the sub-scanning direction.

[0031] The solid line indicates the brightness level when irradiated from the direction of solid arrow 235 in Fig. 7, and the dashed line indicates the brightness level when irradiated from the direction of dashed arrow 236 in Fig. 7. In Fig. 7, light guide 208 that irradiates light in the direction of solid arrow 235 is disposed on the white reference portion 224W side in the sub-scanning direction with respect to rod lens array 209. The light is irradiated from the white reference portion 224 side toward the black portion 224B side. The light guide with respect to dashed arrow 236 is not shown.

[0032] As shown by the solid line in Fig. 12, the brightness level can be considered to be a constant value from the area moved from reference position c toward the white reference portion 224W side by stable distance 1 (approximately 0.5 mm). However, as shown by the dashed line, the brightness level can be considered to be a constant value from the area moved from reference position c toward the white reference portion 224W side by stable distance 2 (approximately 5 mm). The white reference portion up to this stable distance cannot be used as the white reference portion for shading correction. This is because when light is irradiated from the black portion 224B side toward the white reference portion 224W side, the brightness of the white reference portion becomes slightly darker due to the influence of the black portion. Note that if the light does not become darker, it is acceptable to irradiate light from the dashed arrow 236.

[0033] In this embodiment, the light is emitted in the direction of solid arrow 235 shown in Fig. 7, from the white reference portion 224 side to the black portion 224B side. Therefore, it is possible to minimize the width of the reference member 224 in the sub-scanning direction without reducing the shading accuracy. That is, in this embodiment, the image quality of the read image is improved, and the device can be made more compact.

[0034] As described above, when performing the reading operation and the shading process, both rollers are in contact with the rear surface of the platen glass, and when reading the reference mark, only one roller can be in contact with the rear surface of the platen glass. This allows the length of the platen glass to be reduced, and the accuracy of the reading operation and the shading process is not reduced. [Explanation of symbols]

[0035] 202 Document glass 204 Glass Frame 205 Adjacent 207 Reading Unit 224 Reference Component

Claims

1. a first glass on which a document is placed on the front side; An adjacent portion adjacent to the first glass; a reading unit that can come into contact with at least one of the adjacent portion and the first glass, and that reads an original placed on the first glass from a rear surface side of the first glass by a sensor while moving in a moving direction from the adjacent portion side; a position reference unit that is disposed on the front surface side of the first glass and serves as a reference for a position of the reading unit in the moving direction, The image reading device according to claim 1, wherein the reading unit abuts against the adjacent portion and the first glass when reading the position reference portion with the reading unit.

2. a white reference portion provided on the front surface side of the first glass for correcting the image read by the reading unit; 2. The image reading device according to claim 1, wherein, when reading the white reference portion, the reading unit abuts against the first glass without abutting against the adjacent portion.

3. a black portion provided on the front surface side of the first glass and adjacent to the white reference portion on the side of the adjacent portion in the moving direction; 3. The image reading device according to claim 2, wherein the position reference portion is a boundary between the white reference portion and the black portion.

4. 4. The image reading device according to claim 1, further comprising a second glass plate that comes into contact with the transported document on an opposite side of the first glass plate with respect to the adjacent portion in the moving direction.

5. 5. The image reading device according to claim 4, wherein a separating surface for separating the documents is formed above the adjacent portion.

6. 6. The image reading device according to claim 4, wherein the second glass is held by a glass frame that holds the first glass.

7. The reading unit includes a light source.

7. The image reading device according to claim 1, wherein the sensor is disposed on an opposite side of the light source in the direction of movement.

8. the reading unit has a first contact portion and a second contact portion aligned in the movement direction from the adjacent portion side, 8. The image reading device according to claim 1, wherein when the reading unit reads the position reference portion, the first abutment portion abuts against the adjacent portion and the second abutment portion abuts against the first glass.

9. 9. The image reading device according to claim 8, wherein a distance between the first contact portion and the sensor in the movement direction is longer than a distance from a boundary between the adjacent portion and the first glass to the position reference portion.

10. 9. The image reading device according to claim 8, which derives from claim 2, wherein a distance between the first contact portion and the sensor in the movement direction is shorter than a distance from the position reference portion to an end of the white reference portion.

11. 11. The image reading device according to claim 8, wherein the first contact portion and the second contact portion are rotating rollers.

12. 3. The image reading apparatus according to claim 2, wherein the reading unit starts reading the document after reading the white reference portion.

13. An image reading device according to any one of claims 1 to 12, A printing apparatus including a printing unit that records an image on a sheet.

Images