JP4678167B2 - Image reading device - Google Patents

Description

The present invention relates to an image reading apparatus using a document cover.

2. Description of the Related Art Conventionally, there has been known an image reading apparatus that presses a document placed on a document table with a document mat (see, for example, Patent Document 1). A conventional original mat is composed of, for example, a urethane material and a resin sheet attached to the urethane material.
However, when a urethane material is used, there is a problem that the cost is high because the material cost for the urethane material is required and the processing cost for processing the urethane material into a predetermined shape is required.

Conventionally, there are known document covers that contain a film transport device that transports a film such as a 35 mm strip film to a document reading area of an image reading device, and a transmission light source unit that illuminates a transparent document such as a film. Yes. When a film transport device or a transmission light source unit is accommodated in the document cover, the document cover becomes thick, resulting in a problem that the size of the image reading device increases in the height direction.
JP 2003-75944 A

The present invention has been created in view of such problems, and an object thereof is to provide a low-cost original mat.
Another object of the present invention is to provide an original mat that reduces the thickness of the original cover, an original cover using the original mat, and an image reading apparatus using the original cover.

In order to achieve the above object, a document mat according to the present invention is a document mat for pressing a document placed on a document table of an image reading apparatus, the sheet holding the document, and the sheet stretched flat. A locking portion that locks both ends of the sheet, wherein the locking portion is formed in a frame shape, and the frame-shaped surface is in contact with the back surface of the surface of the sheet that holds the document. . According to this original mat, since the urethane material is not used, the cost of the original mat can be reduced.

Furthermore, in the original mat according to the present invention, the locking portion is formed in a frame shape, and the frame-shaped surface is in contact with the back surface of the surface of the sheet that holds the original. According to this original mat, the frame-shaped surface comes into contact with the back surface of the sheet, so that bending of the intermediate portion of the sheet can be prevented and the original can be pressed more reliably.
Further, in the original mat according to the present invention, the sheet is provided apart from the back side of the sheet pressing surface of the sheet in a direction perpendicular to the back side, and when the sheet is pressed against the original and bent toward the counter original plate side, A sheet pressing portion that contacts the back surface of the sheet is further provided. According to this original mat, when the sheet is bent by a thick original, the sheet abuts against the sheet pressing portion to prevent further bending, so that even a thick original can be reliably pressed.

  Furthermore, the original mat according to the present invention further includes a substrate on which the locking portion is provided, and the substrate has a recess that is recessed toward the sheet when viewed from the back side of the surface of the sheet that holds the original. According to this original mat, if the original cover to which the original mat is attached has a convex portion that protrudes toward the original mat, the convex portion can be accommodated in the concave portion. Thereby, the thickness of the entire document cover including the document mat can be reduced.

In order to achieve the above object, a document cover according to the present invention relates to the document mat according to any one of claims 1 and 2 that presses a document placed on a document table, and the document mat is detachable. A mat locking portion to be stopped. According to this document cover, since the document mat according to any one of claims 1 and 2 is provided, the cost of the document cover can be reduced.

In order to achieve the above object, an original cover according to the present invention includes an original mat according to claim 3 for holding down an original placed on an original table, and a mat engaging portion for detachably engaging the original mat. And an accommodating space formed by the recess of the original mat. According to the document cover, for example, accessory parts of the document cover can be accommodated in the accommodation space.
Furthermore, the document cover according to the present invention further comprises a convex portion projecting toward the document mat side,
The convex portion is accommodated in the accommodation space. According to this document cover, the thickness of the entire document cover including the document mat can be reduced by projecting a thick part in the document cover as a projection and accommodating the projected projection in the recess. .

In order to achieve the above object, an image reading apparatus according to the present invention includes a document table, a document cover according to claim 4, 5 or 7 that holds the document placed on the document table, and a document table. And an image sensor for reading the placed document. According to this image reading apparatus, since the original mat that does not use the urethane material is provided, the cost of the image reading apparatus can be reduced.

Hereinafter, the best mode for carrying out the present invention will be described based on examples.
FIG. 2A is a schematic diagram of an image scanner 1 as an image reading apparatus according to an embodiment of the present invention. The image scanner 1 is a so-called flatbed type that reads a reflective document placed on a document table 11 or a transparent document conveyed by a film conveyance device 14.
The document table 11 is formed of a transparent plate such as a glass plate, and a document M such as a printed document, a photo, or a book is placed on the surface of the platen.

  The document cover 12 is connected to the housing 13 so as to be swingable from a posture in which the plate surface of the document table 11 is opened by a hinge (not shown) to a posture in which the plate surface of the document table 11 is covered. The document cover 12 accommodates a film transport device 14 for transporting photographic film, a first light source unit (not shown), and the like. The film transporting device 14 transports the 35 mm strip film inserted from the insertion port 15 onto the opening 18 of the film transporting device 14 with the belt 17 hung on the pulley 16. When reading the film, the original mat 19 is removed, and the lower surface of the film conveying device 14 is in pressure contact with the surface of the original table 11. A first light source unit (not shown) includes a first light source, a reflector, a diffusion plate, an inverter circuit for the first light source, and the like. The light emitted from the first light source is reflected by the reflector, diffused by the diffusion plate, and illuminates the film conveyed to the opening with uniform illuminance from the side opposite to the document table 11.

  The original mat 19 is detachably attached to the original cover 12. The original mat 19 presses down the original M placed on the surface of the original table 11 and covers the original table 11 so that light other than the light emitted from the second light source 20 does not illuminate the original M. The original mat 19 is attached to the original cover 12 by being engaged with a mat engaging portion (not shown) of the original cover 12 when reading a reflection original, and is removed when reading a transparent original such as a film.

  The carriage 21 is slidably fitted to a guide rod 24 that is parallel to the surface of the platen 11. The carriage 21 is mounted with a second light source 20, a mirror 25, a lens 26, and an image sensor 27. The carriage 21 is pulled by a belt 23 hung on a pulley driven by a carriage conveyance motor 22 and reciprocates in the α direction parallel to the surface of the platen 11. The image reading device may be a mirror moving type in which the positions of the image sensor and the lens are fixed with respect to the document table, and the main scanning range is moved in the width direction by moving a plurality of mirrors in conjunction with each other. A contact image sensor using a rod lens array may be used instead of the reduction optical system.

  The second light source 20 is also composed of a tube illumination device such as a fluorescent tube lamp. The second light source 20 is mounted on the carriage 21 so that its longitudinal axis extends in a direction perpendicular to the longitudinal axis of the guide rod 24 and parallel to the document table 11. The reflected light on the main scanning range of the reflective original irradiated to the second light source 20 is reflected by the mirror 25 and enters the lens 26, and is condensed on the light receiving surface of the image sensor 27 by the lens 26.

  The image sensor 27 is a so-called linear image sensor in which a large number of photoelectric conversion elements (not shown) composed of photodiodes or the like are linearly arranged. The image sensor 27 is mounted on the carriage 21 so that a large number of photoelectric conversion elements are arranged in parallel with the central axis of the tubular second light source 20. Electric charges corresponding to the amount of received light are accumulated in each photoelectric conversion element of the image sensor 27 by photoelectric conversion. The electric charge accumulated in each photoelectric conversion element is transferred to the output unit of the image sensor 27 by a CCD (Charge Coupled Device) or the like. The analog image signal output from the image sensor 27 is converted into a digital signal by the AFE unit 36 shown in FIG.

FIG. 2B is a block diagram illustrating a hardware configuration of the image scanner 1.
The image scanner 1 includes a control unit 31, a first illumination unit 32, a second illumination unit 33, an image sensor 27, a main scanning drive unit 34, a carriage transport unit 35, an analog front end (AFE) unit 36, and a digital image processing unit 37. , And an interface 38. The image scanner 1 is connected to a personal computer (PC) 40 or the like via a communication line, for example, a USB (Universal Serial Bus) cable via the interface 38. The control unit 31 is also connected to the film transport device 14.

  The control unit 31 includes a CPU, a ROM, and a RAM. The CPU executes a program stored in the ROM and controls each unit of the image scanner 1 to read a document placed on the document table 11. The ROM is a non-volatile memory that stores various programs and various data, and the RAM is a memory that temporarily stores various programs and various data.

The 1st illumination part 32 is comprised from the 1st light source unit mentioned above, the control circuit for 1st illumination parts, etc. The control circuit for 1st illumination parts receives the 1st illumination part control signal transmitted from the control part 31, and controls lighting of the 1st light source, and light extinction.
The 2nd illumination part 33 is comprised from the 2nd light source 20 mentioned above, the inverter circuit for 2nd light sources which is not shown in figure, the control circuit for 2nd illumination parts, etc. The second illumination unit control circuit receives the second illumination unit control signal transmitted from the control unit 31, and controls turning on and off of the second light source 20.

The main scanning drive unit 34 is a drive circuit that outputs drive pulses necessary for driving the image sensor 27 to the image sensor 27, and includes a synchronization signal generator, a drive timing generator, and the like.
The carriage transport unit 35 includes the above-described carriage transport motor 22, a carriage transport motor drive circuit, a carriage drive unit control circuit, and the like. The carriage drive unit control circuit receives the carriage conveyance control signal transmitted from the control unit 31 and controls the rotation direction, rotation speed, and the like of the carriage conveyance motor 22.

The analog front end (AFE) unit 36 includes an analog signal processing unit, an A / D converter, and the like. The analog signal processing unit performs amplification, noise reduction processing, and the like on the analog image signal output from the image sensor 27. The A / D converter quantizes the analog image signal output from the analog signal processing unit, and outputs a digital representation pixel value of a predetermined bit length for each photoelectric conversion element of the image sensor 27.
The digital image processing unit 37 performs processing such as shading correction and gamma correction on the pixel value output from the AFE unit 36 to generate digital image data.

Next, the original mat will be described.
FIG. 3 is a perspective view of the original mat 19 as viewed from the side where the sheet 45 is stretched. A surface 45b shown in FIG. 3 is a surface for pressing the document. The original mat 19 includes a substrate 44 and a sheet 45 that holds the original. Specifically, the material of the sheet 45 is, for example, a polyester film.

  4A is a perspective view showing a cross section of the original mat 19 and the housing 13, and FIG. 4B is an enlarged view of a rectangular region 50 indicated by a broken line in FIG. 4A. The substrate 44 is formed in a flat plate shape, and when viewed from the document table 11 side, a locking portion 46 that protrudes in a rectangular shape toward the document table 11 side, and a recess that is recessed from the approximate center of the locking portion 46 to the side opposite to the document table 11. 47 and a sheet pressing portion 48 projecting in a rectangular shape from the approximate center of the concave portion 47 toward the document table 11 side. Since the locking portion 46 is formed with the concave portion 47, as a result, the locking portion 46 protrudes into a frame shape. The outer peripheral shape of the locking portion 46 is substantially the same shape as the document table 11 and is formed slightly smaller than the document table 11. Further, a rectangular opening 49 is formed in the original mat 19 so as to straddle the locking portion 46 and the concave portion 47.

  FIG. 5 is a cross-sectional view of a part of the original mat 19 and the original table 11. One end portion of the stretched sheet 45 is bonded to the surface of the bottom wall portion 53 of the locking portion 46 facing the document table 11 with a double-sided tape or an adhesive. The same applies to the other end of the sheet 45 (not shown). Thereby, both ends of the sheet 45 are locked to the locking portions 46 in a stretched state as shown in FIG. The portion of the sheet 45 that protrudes from the locking portion 46 is fixed by being sandwiched between the first support portion 50 and the second support portion 51 that protrude from the substrate 44. As described above, the locking portion 46 is formed in a frame shape, and the frame-shaped surface of the locking portion 46 contacts the sheet 45. For this reason, it is possible to prevent the intermediate portion of the sheet 45 from being bent and to press the document more reliably.

The locking portion 46 is composed of a wall portion 52 and a bottom wall portion 53. Accordingly, the original mat 19 has a recess recessed on the sheet 45 side opposite to the sheet 45 side with the locking portion 46 interposed therebetween. Forms a recess 54 indicated by hatching in FIG.
The surface of the recess 47 facing the side opposite to the sheet 45 is located on the sheet 45 side of the surface 44 a of the substrate 44 facing the side opposite to the sheet 45. Accordingly, the recess 47 forms a recess recessed toward the sheet 45 on the side opposite to the sheet 45 with the engaging portion 46 interposed therebetween, specifically, a recess 55 indicated by hatching in FIG. The side wall of the recess 47 also serves as a rib that prevents the bottom wall portion 53 of the locking portion 46 from bending. In addition, as shown in FIG. 5, you may provide the rib 57 for preventing the bending of the bottom wall part 53 separately. Similarly to the locking portion 46 and the recessed portion 47, the sheet pressing portion 48 also forms a recess 56 indicated by hatching in FIG. The dent 54, the dent 55, and the dent 56 are recessed toward the sheet 45 when the original mat 19 is viewed from the Y direction in the drawing. In other words, the dent 54, the dent 55, and the dent 56 are recessed toward the sheet 45 when the original mat 19 is viewed from the back surface 45a side of the surface 45b (see FIG. 3) of the sheet 45 that holds the original. The dent described in the claims corresponds to the dent 54, the dent 55, and the dent 56.

The sheet pressing portion 48 is provided apart from the back surface 45a of the surface 45b (see FIG. 3) for pressing the document of the sheet 45 in a direction perpendicular to the back surface 45a. Specifically, the sheet pressing portion 48 is provided at a distance of about 0.5 mm in the X direction perpendicular to the back surface 45a from the back surface 45a when the sheet 45 is stretched without bending.
FIG. 6A is a schematic diagram showing a cross section of the original mat 19 and the original cover 12. The cross section of the original mat 19 shown in FIG. 6A is a cross section taken along the line AA shown in FIG. As shown in the drawing, the document cover 12 is formed with a first convex portion 61 projecting toward the document mat 19 side on the side facing the document mat 19 side. Specifically, the first convex portion 61 is a portion projecting toward the document table 11 side of the film transport device 14. When the original mat 19 is attached to the original cover 12, the protruding portion of the film conveying device 14 is accommodated in the recesses 55 and 56 shown in FIG. 5 as shown in FIG. In addition, you may accommodate in the dent 54. As described above, when the recesses 54, 55, and 56 are provided in the original mat 19, the portion protruding from the original cover 12 can be accommodated. For this reason, when there is a part thicker than other parts among the constituent parts accommodated in the document cover 12, the part is projected and the projected part is accommodated in the recess of the document mat 19. The entire thickness of the document cover 12 including the document mat 19 can be reduced. As a result, the thickness of the entire image scanner 1 can be reduced. When the original mat 19 is configured without using the urethane material, the original cover 12 can be made thin because the original mat 19 can secure a dent as described above.

  FIG. 6B is a schematic diagram showing a cross section of the original mat 19 and the original cover 12. The cross section of the original mat 19 shown in FIG. 6B is a cross section taken along line BB shown in FIG. As shown in the figure, the document cover 12 is formed with a second convex portion 62 projecting to the document mat 19 side on the side facing the document mat 19 side. Specifically, the second convex portion 62 is, for example, a first light source inverter circuit. When the original mat 19 is attached to the original cover 12, the first light source inverter circuit is accommodated in the opening 49 of the original mat 19 as shown. As described above, when the opening 49 is provided in the original mat 19, a portion that cannot be accommodated in the recess 47 can be accommodated. In addition, the 2nd convex part 62 may be a 1st light source unit, for example.

Next, the operation of the original mat 19 will be described.
FIG. 1A is a schematic diagram showing a state where a thin original 71 such as paper placed on the original table 11 is pressed by the original mat 19. In the case of the thin document 71, the outer edge portion of the document 71 is pressed against the locking portion 46 via the sheet 45, and thus is pressed against the surface of the document table 11 without warping. The central portion of the document 71 is pressed by the tension of the sheet 45 that is locked in a stretched state, and is pressed against the surface of the document table 11 without warping.

  FIG. 1B is a schematic diagram showing a state in which the book 72 placed on the document table 11 is pressed by the document mat 19. In the case of a thin original such as paper, the sheet 45 does not bend toward the side opposite to the original platen 11, but in the case of a thick original such as the book 72, the sheet 45 is bent depending on the thickness of the original. However, since the sheet pressing portion 48 is provided in the vicinity of the sheet 45, when the sheet 45 is bent to some extent, the sheet 45 is brought into contact with the sheet pressing portion 48 as shown in the drawing to prevent further bending. Therefore, even a thick original can be reliably pressed. Further, if the sheet pressing portion 48 prevents the sheet 45 from being greatly bent, the sheet 45 is extended by repeated large bending by the thick original, and thereby the tension of the sheet 45 is lost. It is possible to prevent even a thin document from being pressed.

According to the original mat 19 of the present invention described above, the original mat 19 can be configured without using a urethane material. Therefore, the cost of the original mat 19 can be reduced.
Further, according to the original mat 19 of the present invention, the sheet 45 is locked to the locking portion 46 in a stretched state, so that the distortion of the sheet 45 can be almost eliminated. Specifically, a recess 47 is formed at the center of the frame-shaped locking portion 46, and the stretched sheet 45 is locked so as to cover the recess 47. Thus, the distortion of the portion covering the recess 47 can be almost eliminated. For example, it is also conceivable to form the original mat 19 by projecting the locking portion 46 into a rectangular shape instead of a frame shape and attaching the sheet 45 to the entire plane. However, when the original is pressed with the sheet 45 attached to the entire plane, if the plane to which the sheet 45 is attached is distorted, the sheet 45 is also distorted, and the original does not contact the original mat 19 when the original is pressed. There is a possibility that a part is generated, and the part is lifted from the document table 11 to deteriorate the image quality. Therefore, the plane on which the sheet 45 is attached must be formed without distortion. However, if an attempt is made to form a flat surface with high accuracy so that the sheet 45 is not distorted, the manufacturing cost increases, and as a result, the cost cannot be reduced. If the sheet 45 is stretched so as to cover the recess 47 by providing the recess 47, the sheet 45 can be made almost flat. Therefore, it is easier to distort the sheet 45 than when the plane 45 is accurately formed and the sheet 45 is stretched on the plane. Can be eliminated. Therefore, the original mat 19 having a small distortion of the sheet 45 can be manufactured at a low cost.

  In the first embodiment, the case where the document cover 12 is provided with the first convex portion 61 and the second convex portion 62 projecting toward the document mat 19 side is described as an example. The protrusion may not be provided. In that case, the recesses 54, 55, and 56 may accommodate accessory parts of the image scanner 1.

(Second embodiment)
FIG. 7A is a perspective view schematically showing the substrate 76 of the original mat 75 according to the second embodiment, and FIG. 7B is a cross-sectional view taken along line AA shown in FIG. . The substrate 76 of the second embodiment is provided with a locking portion 77 that projects in a generally rectangular shape, and an opening 78 is formed in the approximate center of the locking portion 77. That is, the original mat 75 of the second embodiment is not formed with the recess 47 formed in the original mat 19 of the first embodiment. The sheet 45 is locked in a stretched state by adhering both ends to the surfaces 77 a and 77 b of the locking portion 77.

(Third embodiment)
FIG. 8 is a perspective view schematically showing the substrate 82 of the original mat 81 according to the third embodiment. A cross-sectional view taken along line BB of the original mat 81 according to the third embodiment has the same shape as FIG. As shown in the figure, the substrate 82 of the third embodiment is provided with locking portions 83 that are spaced apart from each other and extend in parallel. The sheet 45 is locked in a stretched state by bonding both ends to the surfaces 83a and 83b of the locking portion 83. The third embodiment is substantially the same as the second embodiment in other points.

(Fourth embodiment)
FIG. 9 is a perspective view schematically showing the substrate 86 of the original mat 85 according to the fourth embodiment. As shown in the drawing, the original mat 85 of the fourth embodiment has a prismatic locking portion 87 formed on a substrate 86. The original mat 85 of the fourth embodiment can increase the strength of the locking portion 87 compared to the original mat 81 of the third embodiment.

(A) And (B) is a schematic diagram which shows a mode that the original mat which concerns on 1st Example of this invention has hold | suppressed the original. (A) is a schematic diagram of an image reading apparatus according to the first embodiment of the present invention, (B) is a block diagram thereof. 1 is a perspective view of a document mat according to a first embodiment of the present invention. (A) is a perspective view showing a cross section of the original mat and the image reading apparatus according to the first embodiment of the present invention, and (B) is an enlarged view of a rectangular area indicated by a broken line in (A). 1 is a cross-sectional view of a part of a document mat and a document table according to a first embodiment of the present invention. FIG. 4A is a schematic diagram showing a cross section of the original mat and the original cover according to the first embodiment of the present invention taken along line AA shown in FIG. 4A, and FIG. Sectional drawing of a B line. (A) is a perspective view schematically showing a substrate of an original mat according to a second embodiment of the present invention, and (B) is a sectional view taken along line AA shown in (A). The perspective view which shows typically the board | substrate of the original mat concerning the 3rd Example of this invention. The perspective view which shows typically the board | substrate of the original mat concerning 4th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image scanner, 11 Document stand, 12 Document cover, 19 Document mat, 27 Image sensor, 45 Sheet, 45a Back surface, 46 Locking part, 48 Sheet pressing part, 54, 55, 56 Recess, 61 First convex part ( Convex part), 62 second convex part (convex part), 75 original mat, 77 locking part, 81 original mat, 83 locking part, 85 original mat, 87 locking part

Claims (1)

The document table,
A document cover covering the document table and containing a film transport device;
A document mat attached to the document cover;
A sheet that is adhered to the document mat and covers the document placed on the document table and presses the document against the document table;
The document mat said sheet is formed like a frame adhered portion, abuts against the rear face of the front face frame-shaped face presses the original of the sheet, convex opposite ends of the sheet taut flat and a locking portion for locking in parts,
A concave portion is formed with respect to the convex portion on the inner surface of the original mat on the film conveying device side, and a part of the film conveying device is accommodated in the concave portion .

Images