JP2010192981A - Verification unit, image reader, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress deterioration in the information quality of an original document, when reading the original document floating on a reading surface. <P>SOLUTION: An image reading apparatus includes: a light source section having a plurality of light sources arranged therein; a reflecting mirror section for reflecting light emitted from the light source so as to propagate it toward the original document reading surface of the image reading apparatus; a light dispersion section for dispersing light emitted from the light source section and light reflected on the reflection mirror section; and an opening section for allowing part of light reflected by an original document on the original document reading surface to pass. The light dispersion section is arranged near the original document reading surface so that the light emitted from the light source section and light reflected by the reflection mirror section can unfailingly pass, before reaching the image reading surface, and is bent so as not to close the upper part of the opening section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination unit, an image reading apparatus, and an image forming apparatus that illuminate a document passing on a document reading surface or illuminate a document by scanning the document on the document reading surface.

  2. Description of the Related Art Image forming apparatuses typified by copiers, scanners for reading document information, and the like include an illumination unit for illuminating a document when reading information. The illumination unit reads the document information by illuminating the document passing on the document reading surface. Alternatively, the illumination unit itself moves to illuminate the original placed on the original reading surface while scanning and read the original information.

  In these apparatuses, it is necessary to uniformly illuminate a document in order to read information with high accuracy. From this viewpoint, various techniques for illuminating a document uniformly and efficiently have been proposed.

  For example, the technique described in Patent Document 1 attempts to increase the light use efficiency by reflecting illumination light from a light source with a mirror, and to illuminate the document surface uniformly.

  However, in the technique of Patent Document 1, since the normal direction of the light emitting surface of the light source is directly directed to the document surface, illumination unevenness is theoretically possible in the light source arrangement direction. Even in this case, a document placed in close contact with the document surface can be satisfactorily read with uniform illumination light. For example, the image sensor can be applied to the image sensor of the image reading device in a direction perpendicular to the document reading surface. Assuming that a light beam is incident, the document floats, and the angle formed by the normal direction of the document and the normal direction of the document reading surface is equal to the direction in which the light beam enters the document surface and the normal direction of the document reading surface. If the document is placed so as to be twice the angle formed, the specularly reflected light of this strong light will directly reach the image sensor, and the document information will be read correctly as a whiteout image. Will not be able to.

  Accordingly, the present invention has been made in view of the above problems, and an illumination unit, an image reading apparatus, and an image forming device capable of suppressing quality deterioration that occurs in document information read when reading a document floating from a reading surface. An object is to provide an apparatus.

  In order to solve the above-described problems, an illumination unit according to the present invention includes a light source unit in which a plurality of light sources are arranged and light emitted from the light source toward an original reading surface of the image reading device. A reflecting mirror unit that reflects the light, a light diffusing unit that diffuses the light emitted from the light source unit and the light reflected by the reflecting mirror unit, and the light reflected by the document on the document reading surface. The light diffusing unit is disposed near the document reading surface, and the light emitted from the light source unit and the light reflected by the reflecting mirror unit. Are arranged so as to pass through before reaching the image reading surface, and are bent so as not to block the upper portion of the opening.

  An image reading apparatus according to the present invention includes the illumination unit according to the present invention, the document reading surface for reading a document, the light emitted from the light source, reflected by the document on the document reading surface, and passed through the opening. A second reflection mirror that reflects light; an imaging lens that forms an image of the light reflected by the second reflection mirror; and an optical signal generated by the light imaged by the imaging lens as an electrical signal. And an imaging device for conversion.

  An image forming apparatus according to the present invention includes the image reading apparatus according to the present invention.

  According to the present invention, it is possible to suppress deterioration in quality that occurs in document information read when a document floating from the reading surface is read.

It is a mechanism figure of an example of the illumination unit which concerns on embodiment of this invention. It is a mechanism figure of an example of the illumination unit which concerns on embodiment of this invention. It is a mechanism figure of an example of the illumination unit which concerns on embodiment of this invention. It is a mechanism figure of an example of the illumination unit which concerns on embodiment of this invention. It is a mechanism figure of an example of the illumination unit which concerns on embodiment of this invention. It is a figure which shows an example of the arrangement | sequence of LED in the illumination unit which concerns on embodiment of this invention, and the illumination distribution on the original surface by the arrangement. 1 is a mechanism diagram of an example of an image reading apparatus including an illumination unit according to an embodiment of the present invention. 1 is a mechanism diagram of an example of an image reading apparatus including an illumination unit according to an embodiment of the present invention. 1 is a mechanism diagram of an example of an image forming apparatus including an illumination unit according to an embodiment of the present invention. It is a mechanism figure of an example of the conventional lighting unit. It is the figure which showed an example of luminance signal distribution when the abnormal signal by regular reflection occurred. It is a mechanism figure of an example of the conventional lighting unit.

  Next, embodiments for carrying out the invention will be described in detail with reference to the drawings.

  FIG. 1 shows an embodiment of the present invention. LEDs as light sources are arranged on the substrate at a predetermined interval, and two mirrors that collect light emitted outside the effective range are arranged in front of the light emission direction of the LEDs. A diffusion plate is arranged further forward.

  Consider a case in which a bent document such as a thick book binding portion as shown in FIG. 10 is to be read. In the prior art, since a diffusion plate is not disposed, the light that is regularly reflected on the floating portion of the document sometimes enters the opening vertically. In the case of FIG. 10, since the reading direction of the document information is the normal direction of the document table, the position of the illuminated document when θ is the angle between the illumination direction of the illumination unit and the normal direction of the document table. When the angle between the normal direction of the original surface and the normal direction of the original table is θ / 2, regular reflected light enters the reading direction of the original information. At this time, a luminance signal corresponding to the LED arrangement as shown in FIG. 11 appears and is recognized as an abnormal image.

  Therefore, when a diffusion plate having a light diffusion effect is inserted between the light source unit and the original as in the present invention, the luminance signal as shown in FIG. 11 can be reduced. By doing so, the light from the light source is not directly incident on the document surface, and even when a floating document is read, the directly incident light is diffused, so the quality of the read information of the document is deteriorated. Can be suppressed.

  Also, when collecting light with a mirror as in the present invention, if the mirror is made as large as possible so as to collect light as much as possible, the reflected light from the mirror near the opening for reading document information as shown in FIG. Directly illuminate the original without passing through. At this time, if the diffusing plate is extended in the direction parallel to the document table in order to prevent the original surface from being directly illuminated, the opening is blocked by the diffusing plate, and the reflected light from the original is scattered by the diffusing plate. It will end up.

  Therefore, in the present invention, the diffusion plate is bent and extended in the vicinity of the opening as shown in FIG. 1, and the light beam is prevented from going directly to the document without passing through the diffusion plate as shown in FIG. By doing so, the light reflected by the reflecting mirror is effectively diffused together with the light emitted from the light source toward the direct document, and unnecessary direct incident light can be prevented.

  The range where the diffuser plate extends should block the line (two-dot chain line in the figure) connecting the end on the opening side of the mirror arranged near the opening and the upper end on the opposite side of the opening. Is desirable. With this arrangement, the illumination light from the light source unit can be effectively scattered, and the light source unit can be used even when working with the pressure plate holding the document open (when reading a document such as a book). The LED is not directly observed, so that the user is not dazzled and is safe.

  When a diffusion plate having a large diffusion degree is used, the transmittance of the diffusion plate is lowered according to the diffusion action. In order to avoid this, in the present invention, the diffusion plate is disposed near the document table. At this time, since the distance between the LED, which is a light source, and the diffusion plate is increased, a sufficient diffusion effect can be obtained even with a diffusion plate having a small diffusion effect. Moreover, even if it looks directly at a light source part by this, since the light from LED becomes a big image which spread on the diffusion plate, the advantage that it is also easy to eyes is acquired.

  The light source used in this embodiment is not limited to the LED, but an illumination unit with low power consumption can be configured by using the LED. Furthermore, since the time from when the current is supplied to when the light quantity is stabilized is shorter than that of the cold cathode tube that has been conventionally used to reduce the size of the illumination system, it is possible to save time until the document reading is started. It also has the advantage of not containing environmental pollutants such as mercury.

  Although not shown, it is preferable that the diffusion plate has a random uneven shape on the side of the original surface through which light from the light source is transmitted and emitted. For example, if the light source side on which the light from the light source is incident is uneven, and the document surface side is a mirror surface, the same effect can be obtained as long as it has a diffusing action. The light is reflected by the mirror surface of the diffuser plate, resulting in multiple reflections with the back of the document table. When this multiple reflected light forms an image on the image sensor, it becomes a noise component. Therefore, in order to reduce the multiple reflection, it is preferable that the document surface side is an uneven surface.

  Although the diffusion plate is bent and extended in the vicinity of the opening in FIG. 1, the diffusion plate can be curved as shown in FIG. By arranging the curved diffusion plate so as to block the line connecting the mirror end near the opening and the upper end of the opposite opening, the same action as in FIG. 1 can be obtained.

  FIG. 3 shows an example in which two illumination units are arranged so as to face both sides of the opening in the scanning direction (left and right direction on the paper). In this case, since the upper end of the opening is the end of the diffusion plate, each diffusion plate is arranged so as to block the line connecting the end of each mirror and the upper end of the diffusion plate of the opposing illumination unit. It is desirable to do. By arranging on both sides of the opening in this way, it is possible to arrange more light source units than arranging only on one side, resulting in a brighter illumination unit and illuminating the document surface from both sides Therefore, even if you scan a document that has shadows with only one side of the illumination, such as a document with a step (a clipped document), it is difficult to create shadows and it is possible to suppress the occurrence of abnormal images. .

  In addition, when the diffusion plate is curved as in FIG. 2 as shown in FIG. 4, the two diffusion plates are arranged so that the straight line from the mirror end of the opposing illumination unit is in contact with the curved portion of each diffusion plate. By setting the position, the same effect as in FIG. 3 can be obtained.

In FIG. 5, the light source is only on one side, but a reflecting mirror is arranged on the opposite side of the opening so as to reflect the light from the light source so that the document can be illuminated from both sides of the opening. In addition, mirrors for condensing light from the light source are also arranged, and diffuser plates that are bent so that light does not go directly to the original are arranged on both sides of the opening. In the present embodiment, the lighting unit can be reduced in size and power can be saved as compared with the case where the light source units are arranged on both sides as shown in FIGS.
In addition, since there is a space between the end of the mirror disposed near the opening and the end of the extension of the diffusion plate, the light emitted from the light source is on the opposite side of the opening without passing through the diffusion plate. It is possible to effectively reach the arranged reflection mirror (shaded area), and it is possible to perform good double-sided irradiation without reducing the illumination ratio of double-sided irradiation.

  The embodiment of FIG. 6 shows the arrangement of LEDs relative to the substrate. By arranging the LEDs at equal intervals with respect to the substrate, uniform illumination can be obtained on the original surface in the LED arrangement direction. However, as shown in FIG. High illumination illuminance can be obtained at both ends of the substrate by making it narrower than the array interval P1 of the LEDs in the part. By arranging in this way, it is possible to suppress a decrease in the amount of peripheral light on the image sensor that occurs at the angle of view of the imaging lens when reading the document information after being reduced by the imaging lens.

  In each embodiment of the present invention, a configuration with a minimum number of mirrors is shown. It is also possible to increase the number of mirrors and collect light more efficiently on the document surface than in this embodiment.

  FIG. 7 shows an embodiment of the image reading apparatus of the present invention. The original 12 to be read is placed in a plane on the contact glass 11 corresponding to the “original table” in FIG. 1, and illumination means is disposed below the contact glass 11. As the illumination means, the illumination unit 13A according to the present invention in which light sources are arranged in a direction orthogonal to the plane of FIG. 7 is used to illuminate the “slit-like portion extending in the direction orthogonal to the plane of FIG. Reflected light from the illuminated portion of the document 12 (reflected light from the image) is reflected by the first mirror 13B provided on the first traveling body 13, and then is provided on the second traveling body 14. 14A and the third mirror 14B are sequentially reflected, pass through the imaging lens 15, and form a reduced image of the original image on the imaging surface of the line sensor 16 as a photoelectric conversion element as an imaging element.

  The first to third mirrors 13B, 14A, and 14B constitute a “reflection optical system”. The first traveling body 13 and the second traveling body 14 are each moved in the direction of the arrow (to the right in the figure) by driving means (not shown). The moving speed of the first traveling body 13 is “V”, and the moving speed of the second traveling body 14 is “V / 2”. By this traveling, the first traveling body 13 and the second traveling body 14 each move to “positions indicated by broken lines”. The illumination unit 13 </ b> A and the first mirror 13 </ b> B move integrally with the first traveling body 13 to “illuminate and scan” the entire document 12 on the contact glass 1. Since the moving speed ratio of the first and second traveling bodies is “V: V / 2”, “the optical path length from the original scanned portion to the imaging lens” is kept unchanged during movement.

  The line sensor 16 that is an “imaging unit” has “a photoelectric conversion element (16A, 16B, 16C) having red (R), green (G), and blue (B) filters as color separation means on one chip. A three-line CCD (three-line line sensor) arranged in three rows ”, which converts a document image into an image signal as the document 12 is illuminated and scanned. In this way, the original 12 is read, and the color image of the original 12 is read by color separation into the three primary colors of red, green, and blue.

  In addition, the image reading apparatus of this embodiment is an apparatus for reading an image in full color, and “color separation means (red, green provided in the three-line CCD” provided in the imaging optical path of the imaging lens 15 is used. , Blue filter).

  As another form of the image reading apparatus, “illuminating means for illuminating the original on the contact glass in a slit shape, a line sensor, and a plurality of mirrors forming an imaging optical path from the illuminated part of the original to the line sensor; The reading unit integrated with the imaging lens disposed on the imaging optical path may be configured to read and scan the document by causing the driving unit to run relative to the document. it can. By adopting such a configuration, a small and energy-saving image reading apparatus can be achieved.

  In “color separation”, a color separation prism or filter is selectively inserted between the imaging lens and the line sensor (CCD) separately from the above, and R (red), G (green), and B (blue). Or a “method of illuminating a document by sequentially turning on R, G, and B light sources”.

  With the image reading apparatus of the present invention, it is possible to read a good image, save energy than conventional xenon and halogen lamps, suppress the generation of heat generation, and to the image sensor due to thermal expansion due to heat generation. It is also possible to suppress deterioration in imaging performance that causes the focus to shift.

  FIG. 8 shows an embodiment of a reading unit used in an image reading apparatus different from FIG. The reading unit shown in FIG. 8 is a reading unit 21 including reflection mirrors 25a, b, and c, an imaging lens 22, a line sensor 24 such as a CCD, an electric circuit 23, and an illumination unit 26 of the present invention. The reading unit 21 illuminates the document 12 placed on the contact glass with the illumination unit while scanning the vicinity of the contact glass 11 in the left-right direction in the drawing, reflects reflected light from the document by a reflection mirror, and forms an imaging lens. The image is reduced and imaged, and the document information is read while performing photoelectric conversion by the line sensor.

  If the reading unit of the present invention is used in an image reading apparatus, good image reading is possible, and the optical path length from the document surface to the image sensor is secured so as to ensure the range of movement of the mirror as shown in FIG. Since it is not necessary to take a long time, a small image reading apparatus is possible. In addition, the image reading apparatus can be achieved without containing harmful substances such as mercury as in the case of conventionally used cold cathode tubes.

  FIG. 9 shows an embodiment of the image forming apparatus of the present invention. The image forming apparatus of the present invention includes an image reading apparatus 200 positioned at the upper part of the apparatus and an “image forming unit” positioned at the lower part thereof. The portion of the image reading apparatus 200 is the same as that described with reference to FIG. 7, and the same reference numerals as those in FIG.

  An image signal output from the three-line line sensor (imaging means) 16 of the image reading apparatus 200 is sent to the image processing unit 1200 and processed by the image processing unit 1200 to obtain a “writing signal (yellow, magenta, cyan, Signal for writing each color of black) ”.

  The image forming unit has a photoconductive photosensitive member 1100 formed in a cylindrical shape as a “latent image carrier”, and around it, a charging roller 1110 as a charging unit, a revolver type developing device 1130, a transfer belt. 1140 and a cleaning device 1150 are provided. As the charging means, a “corona charger” can be used instead of the charging roller 1110.

  An optical scanning device 1170 that receives a writing signal from the signal processing unit 1200 and writes on the photosensitive member 1100 by optical scanning performs optical scanning of the photosensitive member 1100 between the charging roller 1110 and the developing device 1130. ing.

  Reference numeral 1160 denotes a fixing device, reference numeral 1180 denotes a cassette, reference numeral 1190 denotes a registration roller pair, reference numeral 1220 denotes a paper feed roller, reference numeral 1210 denotes a tray, and reference numeral S denotes a transfer sheet as a “recording medium”.

  When performing image formation, the photoconductive photosensitive member 1100 is rotated clockwise at a constant speed, the surface thereof is uniformly charged by the charging roller 1110, and is subjected to exposure by optical writing of the laser beam of the optical scanning device 1170. An electrostatic latent image is formed. The formed electrostatic latent image is a so-called “negative latent image”, and the image portion is exposed.

  “Image writing” is performed in the order of a yellow image, a magenta image, a cyan image, and a black image in accordance with the rotation of the photosensitive member 1100, and the formed electrostatic latent image is converted into each developing unit Y ( Development with yellow toner), M (development with magenta toner), C (development with cyan toner), K (development with black toner) are sequentially reversed and visualized as a positive image. The respective color toner images are sequentially transferred onto the transfer belt 1140 by the transfer voltage application roller 114A, and the respective color toner images are superimposed on the transfer belt 1140 to form a color image.

  The cassette 1180 containing the transfer paper S is detachable from the main body of the image forming apparatus, and the uppermost sheet of the stored transfer paper S is fed by the paper feed roller 1220 when mounted as shown in the figure. The leading edge of the fed transfer paper S is caught by the registration roller pair 1190.

  The registration roller pair 1190 feeds the transfer sheet S to the transfer unit at the timing when the “color image by toner” on the transfer belt 1140 moves to the transfer position. The transferred transfer paper S is superimposed on the color image at the transfer portion, and the color image is electrostatically transferred by the action of the transfer roller 114B. The transfer roller 114B presses the transfer sheet S against the color image during transfer.

  The transfer sheet S to which the color image has been transferred is sent to the fixing device 1160, where the color image is fixed by the fixing device 1160, passes through a conveyance path by guide means (not shown), and is discharged onto the tray 1210 by a pair of paper discharge rollers (not shown). The Each time each color toner image is transferred, the surface of the photoreceptor 1100 is cleaned by a cleaning device 1150 to remove residual toner, paper dust, and the like.

  With the image forming apparatus of the present invention, good image copying is possible. The configuration of the image forming unit can be changed to a well-known configuration for forming a single color image.

  The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments thereof, various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the invention as defined in the claims. is there.

  In the illumination unit according to the present invention, the light diffusing portion may be disposed so as to block a line connecting an end portion on the opening portion side of the mirror portion and an upper end portion on the opposite side of the opening portion. Also good.

  In the illumination unit according to the present invention, the light source may be an LED.

  In the illumination unit according to the present invention, the light diffusing unit may have an uneven shape at least on the document surface side.

  In the illumination unit according to the present invention, the light source unit may be arranged on both sides of the opening.

  In the illumination unit according to the present invention, the light diffusion portion is disposed on both sides of the opening, the reflection mirror portion is disposed on both sides of the opening, and the light source portion is disposed on one side of the opening. It may be arranged only in the.

  The image reading apparatus according to the present invention includes a traveling body including the illumination unit, the second reflection mirror unit, the imaging lens, and the imaging element, and scans the traveling body. Information on the original may be read.

DESCRIPTION OF SYMBOLS 11 Contact lens 12 Document 13 1st traveling body 13A Illumination unit 13B 1st mirror 14 2nd traveling body 14A 2nd mirror 14B 3rd mirror 15 Imaging lens 16 Line sensor

JP 2006-042016 A

Claims (9)

In the image reading device,
A light source section in which a plurality of light sources are arranged;
A reflection mirror that reflects the light emitted from the light source so as to be directed toward the document reading surface of the image reading device;
A light diffusing unit that diffuses the light emitted from the light source unit and the light reflected by the reflecting mirror unit;
An opening for passing a part of the light reflected by the original on the original reading surface;
The light diffusing unit is disposed near the document reading surface, and the light emitted from the light source unit and the light reflected by the reflecting mirror unit always pass through before reaching the image reading surface. The lighting unit is arranged so as to be bent so as not to block the upper portion of the opening.   2. The illumination according to claim 1, wherein the light diffusing portion is disposed so as to block a line connecting an end portion on the opening side of the mirror portion and an upper end portion on the opposite side of the opening portion. unit.   The lighting unit according to claim 1, wherein the light source is an LED.   4. The illumination unit according to claim 1, wherein at least the document surface side of the light diffusing portion has an uneven shape. 5.   The lighting unit according to claim 1, wherein the light source unit is disposed on both sides of the opening. The light diffusion portion is disposed on both sides of the opening,
The reflection mirror part is disposed on both sides of the opening,
The lighting unit according to claim 1, wherein the light source unit is disposed only on one side of the opening. The lighting unit according to any one of claims 1 to 6,
The original reading surface for reading an original;
A second reflecting mirror that is emitted from the light source and is reflected by the document on the document reading surface and reflects the light that has passed through the opening;
An imaging lens that forms an image of the light reflected by the second reflection mirror;
An image reading device comprising: an imaging device that converts an optical signal of the light imaged by the imaging lens into an electrical signal. A traveling body including the illumination unit, the second reflection mirror unit, the imaging lens, and the imaging element;
The image reading apparatus according to claim 7, wherein information on the original is read by scanning the traveling body.   An image forming apparatus comprising the image reading apparatus according to claim 7.

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