JP2006060528A - Contact image sensor, image reading apparatus, image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a smaller and lighter contact image sensor having an improved flexibility in its layout and capable of efficiently using light. <P>SOLUTION: The contact image sensor employs an integrated configuration that comprises a contact glass 12 of an image-formation optical system serving both as protection against dust and a guide for a manuscript and optical sources 13a and 13b for lighting the manuscript. A surface optical sources such as an EL element capable of being mounted on one surface of the contact glass 12 is adopted as the optical sources 13a and 13b. Light shielding members 11a and 11b is disposed at the surface of an image-formation side of contact glass 12 or its near place, in order to shut off harmful flare light which may reach a linear sensor, even if a reading position for the manuscript and the optical sources 13a and 13b are arranged at a close position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a contact image sensor, and more particularly, to an original reading apparatus, an image reading apparatus, or an image forming apparatus such as a copying machine, a scanner, or a fax machine using these.

  When configuring a document reader using a contact image sensor, it is important to improve the degree of freedom of layout and to efficiently use the light quantity of the light source in order to facilitate downsizing, etc. It is.

  For example, on the exit side and the entrance side of the SELFOC (registered trademark) lens (bar-shaped lens) in order to improve the reading accuracy by blocking the intrusion of interfering light, dust and dust entering the light receiving element of the contact image sensor. The two side walls are attached in close contact with the SELFOC (registered trademark) lens, and a skirt is provided between the lower end of the outlet side wall and the lower resin mold to fill the gap between them. In addition, there is a skirt that prevents unnecessary light other than the signal from the original irradiated by the light emitting diode, dust in the frame, and dust from entering (see Patent Document 1).

  A line sensor head that illuminates the object with a line-shaped light source and efficiently arranges the sensitivity of each color ink by arranging a filter at a position that does not interfere with the light incidence from the object to the lens. Is known (see Patent Document 2).

  In addition, an LED, which is a point light source, is installed on the side of the glass, which is also the side of the manuscript interpretation area, and glass and reflectors are used to guide the light to the reading unit. There are also known products that aim to reduce the product volume and reduce the product volume (see Patent Document 3).

Furthermore, in order to obtain a close contact image sensor that can attach the optical system component and the image sensor accurately and easily, a first unit having a first housing with a light source and a cover glass attached thereto, A second unit having a second housing with a rod lens and an infrared cut filter attached to the unit, and a third housing for mounting an image sensor and a sensor substrate to be assembled with the second unit are mounted. There is also known a configuration in which a third unit including an image sensor processing substrate is disposed (see Patent Document 4).
Japanese Utility Model Publication No. 5-2472 Japanese Utility Model Publication No. 5-53353 JP 2002-94742 A Japanese Patent Laid-Open No. 11-32177

  In view of the above, the present invention has an object to provide a novel configuration that improves the degree of freedom in layout and efficiently uses the amount of light from a light source when a document reading apparatus is configured using a contact image sensor. It is what.

  According to a first aspect of the present invention, there is provided a contact image sensor comprising: a dust-proof and document guide contact glass for an imaging optical system; and a document illumination light source, wherein the contact glass and the document illumination light source are integrated. The document illumination light source is provided in parallel with the image reading direction.

  The contact image sensor according to claim 2, wherein the document illumination light source is a surface light source.

  The contact image according to claim 3 is the contact image sensor according to claim 1 or 2, wherein the contact glass has a flat base-type cross-sectional shape in a cross section perpendicular to the image reading direction. Sensor.

  The contact image sensor according to claim 4, wherein the document illumination light source is arranged on a pair of inclined surfaces.

  According to the fifth aspect of the present invention, in the contact image sensor according to any one of the first to fourth aspects, a light shielding member is provided on a surface on the imaging surface side of the contact glass that is opposite to the original or in the vicinity thereof. A close contact image sensor.

  The contact image sensor according to claim 6 is characterized in that in the contact image sensor according to claim 1 or 2, a light emitting surface of the original illumination light source is curved.

  According to the seventh aspect of the present invention, in the contact image sensor according to the sixth aspect, the contact glass has a flat and substantially flat section shape in which both edges in a direction orthogonal to the image reading direction are curved. Contact image sensor.

  A contact image sensor according to claim 8, wherein the document illumination light source is arranged on a pair of curved surfaces.

  According to the ninth aspect of the present invention, in the contact image sensor according to any one of the sixth to eighth aspects, a light shielding member is provided on or near the imaging surface side surface of the contact glass that is opposite to the original. A close contact image sensor.

  The document reading apparatus according to claim 10 is characterized by using the contact image sensor according to any one of claims 1 to 9.

  An image reading apparatus according to claim 11 is characterized by using the contact image sensor according to any one of claims 1 to 9.

  An image forming apparatus according to claim 12 is characterized by using the contact image sensor according to any one of claims 1 to 9, the document reading device according to claim 10, or the image reading device according to claim 11.

  In the present invention, since the contact glass and the light source are integrally formed, there is an effect that the degree of freedom in layout is improved and the size and weight can be easily reduced. Further, since the light source can be brought close to the document surface, the light from the light source can be used efficiently.

  The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 1 is a conceptual cross-sectional view showing an example of an image forming apparatus which is a target using the contact image sensor according to the present invention. The image forming apparatus of this example mainly includes a reading unit 121 that reads a document, an image forming unit 122 that forms an image, an automatic document feeder (hereinafter also referred to as ADF) 123, and a document that stacks documents sent from the ADF 123. A stacker 90, a paper feed unit 129 having paper feed cassettes 125 to 128, and a paper discharge tray 130 for stacking recording papers. In the image forming unit 122, a plurality of image forming units 132 are arranged in parallel on a belt-like intermediate transfer belt 131. In each image forming unit 132, a photoconductor 133 is arranged around a drum-shaped photoconductor 133. A charging device that charges the surface of the photosensitive member 133, an exposure device that irradiates the surface of the photosensitive member 133 with laser light, a developing device that visualizes the electrostatic latent image formed by exposing the surface of the photosensitive member 133, and a photosensitive member A cleaning device that removes and collects toner remaining on the body 133 is disposed.

  The illustrated example is a color image forming apparatus in which the image forming unit 132 is for yellow (Y), magenta (M), cyan (C), and black (BK), for example. While rotating, toners of yellow (Y) to black (BK) are sequentially developed and transferred to the intermediate transfer belt 131, and the four color toner images developed on the intermediate transfer belt 131 are transferred onto a sheet by a transfer device. However, the present invention is not limited to the image forming apparatus of this example, and can be applied to various types.

  FIG. 2 is an enlarged sectional view showing the ADF 123. The ADF 123 includes a document setting unit A for setting a document bundle 13 to be read, a separation feeding unit B for separating and feeding documents one by one from the set document bundle 13, and a primary abutting alignment of the fed documents. In addition, the registration unit C that pulls out and conveys the document after alignment, the turn unit D that turns the conveyed document and conveys the document surface toward the reading side (downward), and reads the surface image of the document from below the reading glass 54. A first reading / conveying unit E for reading, a second reading / conveying unit F for reading the back side image of the original after reading, a paper discharging unit G for feeding the original whose front and back sides have been read to the outside of the machine or the reversing unit, A reversing unit H that performs reversing, a stack unit I that stacks and holds documents after reading, and a driving unit that drives these transport operations, although not shown, It is constituted from a controller unit for controlling.

  In this apparatus, a document bundle P to be read in the document setting section A is set on the document setting table 50, and the pickup roller 51 is pressed against the upper surface of the document with a predetermined force by a document feed signal, and the uppermost sheet of the document bundle P is read. Is fed in the direction of the separation part B. This is separated by a paper feed belt 52 or the like so as not to feed two or more documents, and is fed while preventing double feeding. The document separated into one sheet by the action of the paper feed belt 52 and the like advances through the paper feed path, hits the pair of pull-out rollers 53, and is pressed with a predetermined amount of deflection. Then, it enters the nip of the pull-out roller pair 53, and aligns the tips (corrects skew). Thereafter, the pull-out roller pair 53 is driven to convey the document in the turn portion D direction. Thereafter, the original is sent to the nip between the reading conveyance roller 54 and the pressure roller 55, stopped at a position where the registration sensor 56 has conveyed a predetermined pulse and stopped at the position where it is registered, and synchronized with the reading conveyance roller 54 in synchronization. The sheet is fed into the first reading conveyance unit E by the pressure roller 55.

  In the first reading conveyance section E, the original is conveyed between the reading glass 56 and the white background plate 57 arranged at a predetermined interval with respect to the upper surface thereof, and an image of the original is read by a reading system (not shown) during that time. Then, it is converted into an electrical signal via a CCD (not shown) or the like, and this is also stored in a memory device (not shown). Further, the original image fed from the first reading conveyance unit E by the intermediate conveyance pressure roller 58 is sent to the second reading conveyance unit F, and the contact image sensor 61 arranged with the reading unit facing downward from the upper surface, and the contact image from below. It passes between the pressing members 62 arranged on the reading surface of the sensor 61 with a predetermined pressure and a predetermined interval. Then, after the reading area of the front surface and the back surface of the original is completed, the original is discharged to the stack portion I by a discharge roller pair 63 constituted by a discharge drive roller and a discharge pressure roller.

  The present invention is not limited to the image forming apparatus of this example, and can be applied to various types.

  FIG. 3 is a diagram conceptually illustrating an embodiment of a contact image sensor according to the present invention and an embodiment of a document reading apparatus using the contact image sensor. The main parts of this embodiment are a document table 2 on which the document 1 is placed, a document insertion sensor 3, document feed rollers 4a and 4b, a guide plate 5 (including a plurality of unillustrated ones), a registration roller 6a, 6b, registration sensor 7, linear sensor (a sensor in which a plurality of CCDs and the like are linearly arranged) 8, printed circuit board 9 on which linear sensor 8 is mounted, SELFOC (registered trademark) lens array 10, light shielding members 11a and 11b, image Contact glass 12 having a base-type cross-sectional shape with a flat cross section in a direction orthogonal to the reading direction, planar light source illumination light source (for example, EL element) 13a, 13b, back roller 14, document discharge roller 15a, 15b, and a document receiver 16.

  The document illumination light sources 13 a and 13 b are provided symmetrically on two surfaces facing obliquely upward of the contact glass 12, and are parallel to the image reading direction of the document 1. In the drawing, la indicates light emitted from the document illumination light source 13a, and lb indicates light emitted by the document illumination light source 13b. Reference numeral lc denotes a light beam that is reflected from the document surface of the document 1 and travels toward the SELFOC (registered trademark) lens array 10. The light shielding members 11a and 11b are provided along the image reading direction so as to be lined up inside the document illumination light sources 13a and 13b and sandwiching the light flux lc.

  Although not shown, the rollers 4 a, 6 a, 14, and 15 a are movable in the vertical direction according to the thickness of the document 1. Each roller 4a, 6a, 15a is a driven roller.

  The document 1 is inserted by the operator on the document table 2 in the left direction (forward direction) in FIG. When the document insertion sensor 3 detects the leading edge of the document 1, the document illumination light sources 13a and 13b are turned on, a document transporting moke (for example, a stepping motor) not shown in FIG. 1 is activated, and document feed rollers 4a and 4b, registration The rollers 6a and 6b, the back roller 14, and the document discharge rollers 15a and 15b are sequentially rotated in the forward direction. Then, the document 1 is conveyed in the forward direction, and the leading edge of the document is detected by the registration sensor 7. Thereafter, the linear sensor 8 reads the document 1 on the back roller 13 at the timing.

  The center of the optical path for forming an image on the linear sensor 8 is a perpendicular line connecting each pixel of the linear sensor 8 and substantially the top of the back roller 14. The bottom surface of the contact glass 12, that is, the surface that may come into contact with the top surface of the document 1 is closest to the top surface of the document at almost the top of the back roller 14. The light from the document illumination light sources 13 a and 13 b is reflected by the image surface of the document 1, and forms a document image on the linear sensor 8 via the contact glass 12 and the SELFOC (registered trademark) lens array 10. The light shielding members 11a and 11b are set so as not to pass through the optical path for image formation so that harmful flare light does not go to the linear sensor 8.

  Thereafter, the original 1 is conveyed in the forward direction to read the original. After the rear end of the original 1 passes through the reading portion, the original illumination light sources 13a and 13b are turned off, and the rear end of the original is the original discharge rollers 15a and 15b. After passing, the conveying operation is stopped. The document 1 is placed on the document receiver 16.

  That is, in the contact image sensor of the present embodiment, the contact glass 12 of the imaging optical system serves as dust proof and document guide, and includes document illumination light sources 13a and 13b, which are integrated. For this reason, the degree of freedom of layout is improved, and the size and weight can be easily reduced. If the document illumination light sources 13a and 13b are surface light sources such as EL elements that can be mounted on one surface of the contact glass 12, the document illumination light sources 13a and 13b can be used while maintaining a good illuminance distribution on the document surface. It can be brought close to the surface. This makes it possible to use the light from the light source efficiently.

  Further, since the light shielding members 11a and 11b are disposed on the surface of the contact glass 12 on the image forming surface side (the side opposite to the original 1) or in the vicinity thereof, and the contact glass 12 and the original illumination light sources 13a and 13b are integrated. Even if the reading position of the original surface and the original illumination light sources 13a and 13b are brought close to each other, harmful flare light that reaches the linear sensor can be blocked.

  FIG. 4 is a diagram conceptually showing another embodiment of the contact image sensor according to the present invention. In this embodiment, a contact glass 12 ′ having a flat and substantially square cross-sectional shape in which both edges in a direction orthogonal to the image reading direction are curved, and a document illumination light source 13a ′ attached to both the curved edges, A curved light source is used at 13b '. The document illumination light sources 13a 'and 13b' can also be configured using, for example, EL elements. As in the previous embodiment, the light shielding members 11a and 11b are provided along the image reading direction so as to be lined up inside the document illumination light sources 13a and 13b with the light flux lc interposed therebetween.

  In this embodiment, since the light emitting surfaces of the document illumination light sources 13a 'and 13b' are curved, the light is converged to the reading position on the document surface, and the light from the light source can be used efficiently. Other configurations and operations are the same as those in the previous embodiment, and thus description thereof is omitted.

1 is a conceptual cross-sectional view illustrating an example of an image forming apparatus that is a target using a contact image sensor according to the present invention. Sectional drawing which expands and shows ADF of FIG. 1 is a diagram conceptually illustrating an embodiment of a contact image sensor according to the present invention and an embodiment of a document reading apparatus using the image sensor. The figure which shows notionally other Example of the contact | adherence image sensor based on this invention.

Explanation of symbols

1: Document 2: Document Table 3: Document Insertion Sensor 4a, 4b: Document Feed Roller 5: Guide Plate 6a, 6b: Registration Roller 7: Registration Sensor 8: Linear Sensor 9: Printed Circuit Board 10: Selfoc (Registered Trademark) Lens Array 11a 11b: Light shielding member 12: Contact glass 13a, 13b, 13a ′, 13b ′: Document illumination light source 14: Back roller 15a, 15b: Document discharge roller 16: Document receiver la, lb: Light emitted by document illumination light source lc: Light flux reflected from the original surface

Claims (12)

The contact image sensor includes a dust-proof and document guide contact glass for the imaging optical system and a document illumination light source. The contact glass and the document illumination light source are integrated, and the document illumination light source is parallel to the image reading direction. The contact image sensor characterized by being provided in the. 2. The contact image sensor according to claim 1, wherein the original illumination light source is a surface light source. 3. The contact image sensor according to claim 1, wherein the contact glass has a flat base-type cross-sectional shape in a cross section perpendicular to an image reading direction. 4. The contact image sensor according to claim 3, wherein the document illumination light source is disposed on a pair of slopes. 5. The contact image sensor according to claim 1, further comprising a light shielding member on or near the imaging surface side surface of the contact glass that is opposite to the original. 3. The contact image sensor according to claim 1, wherein a light emitting surface of the original illumination light source is curved. The contact image sensor according to claim 6, wherein the contact glass has a flat, substantially scalloped cross-sectional shape in which both edges in a direction orthogonal to the image reading direction are curved. 4. The contact image sensor according to claim 3, wherein the original illumination light source is disposed on a pair of curved surfaces. 9. The contact image sensor according to claim 6, further comprising a light shielding member on or near the imaging surface side surface of the contact glass that is opposite to the original. An original reading apparatus comprising the contact image sensor according to claim 1. An image reading apparatus comprising the contact image sensor according to claim 1. An image forming apparatus comprising the contact image sensor according to claim 1, the document reading device according to claim 10, or the image reading device according to claim 11.

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