JP2012104877A - Image reading apparatus and image forming apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading apparatus allowing an operator to feel less dazzling to the light emitted from a light source regardless of the direction in which the operator sees the light source, and an image forming apparatus having the same.SOLUTION: An image reading apparatus 100 includes lighting control means 441 for controlling turning on and off for each of light-emitting elements 212(1) to 212(n) or for each of light-emitting element blocks BL(1) to BL(h). If the lighting control means 441 turns on the light-emitting elements 212(1) to 212(n) or the light-emitting element blocks BL(1) to GL(h) before reading an image of a document G when opening and closing detection means 260 detects that a document pressing member 319 is closed, the lighting control means turns on light-emitting elements or light-emitting element blocks in a document region based on the detection results of the document G size detected by document size detection means 270 and turns off light-emitting elements or light-emitting element blocks in regions other than the document region.

Description

  The present invention relates to an image reading apparatus and an image forming apparatus including the same.

  In an image reading apparatus provided in an image forming apparatus such as a copying machine or a multifunction peripheral, or an image reading apparatus connected to a computer via a communication means such as a network, a halogen light source, a xenon light source, or a plurality of light emitting elements (specifically, Is read as a document image from a document illuminated by a light source such as an array light source having LEDs arranged in the main scanning direction.

  As an image reading apparatus, generally, a fixed document reading method for fixing a document and reading a document image, a moving document reading method for moving a document to read a document image, a moving document reading method and a document A combination of fixed reading methods is employed.

  Specifically, in a document fixed reading type image reading apparatus, a light source unit including a light source is placed on a document placing transparent body (specifically, a transparent plate such as a document table glass) while moving in the sub-scanning direction. The original is pressed by a document pressing member (for example, a document pressing cover) and scanned in the main scanning direction through the document placing transparent body, and then a CCD (Charge Coupled Device), a CIS (Contact Image Sensor) or the like is used. Reading is performed by an image reading unit (specifically, a photoelectric conversion element). In the image reading apparatus of the document moving reading method, a reading position of a document conveyed in the sub-scanning direction by an automatic document feeder so as to pass over a document reading transparent body (specifically, a transparent plate such as a document reading glass). Is scanned in the main scanning direction through the original reading transparent body and read by an image reading unit such as a CCD or CIS. Note that, in an image reading apparatus that combines a document moving reading method and a document fixed reading method, the component of the automatic document feeder normally serves as a document pressing member.

  Among such image reading apparatuses, an image reading apparatus having a configuration in which a light source is turned on prior to a reading operation of an image of a document when it is detected that the document pressing member is closed is conventionally known. Yes.

  In the image reading apparatus having such a configuration, for example, a white reference member is provided in an area other than the original reading area, and when reading the original image, the light source unit is positioned at any position (specifically, corresponding to the original reading area). The light source is turned on in the middle of closing when the document pressing member presses the document placed on the document placement transparent body. The white light source member may be read by the image reading unit by moving the light source unit to the white reference member side in a state where the image is read. Then, the read value is used to adjust the level of the amount of light emitted from the light source that emits light when reading the image of the document, or to perform shading correction that makes the value of the received light signal constant.

  In such a conventional image reading apparatus, the light source is turned on in the middle of closing the document pressing member, so that the light from the light source easily enters the eyes of the operator, and the light from the light source makes the operator feel dazzling. It will be.

  In this regard, Patent Document 1 discloses that the optical axis of one linear light source is inclined toward the other linear light source with respect to the direction perpendicular to the mounting surface of the mounting table, and the size of the document on the mounting table is set. An image reading apparatus that discriminates the size of a document without causing the operator to feel the light source emission dazzling by turning off a linear light source having an optical axis in a direction toward the operator among the pair of linear light sources. It is disclosed.

JP 2007-288716 A

  However, in the image reading device described in Patent Document 1, depending on the direction in which the operator looks at the light source, the operator feels dazzled by the light from the light source that protrudes outside the document placed on the document placing transparent body. As a result, problems still remain.

  Therefore, the present invention makes the operator feel dazzled by the light from the light source regardless of the direction in which the operator looks at the light source when the light source is turned on in the middle of closing the document pressing member prior to the document image reading operation. An object of the present invention is to provide an image reading apparatus that can be reduced and an image forming apparatus including the image reading apparatus.

  In order to solve the above problems, the present invention provides a document placing transparent body on which a document is placed and a structure for opening and closing the document placing transparent body. A document pressing member that presses the document placed on the document placement transparent body by closing the document, an open / close detection means that detects opening / closing of the document pressing member, and the document for reading an image of the document An image reading apparatus comprising: a light source unit having a light source in which a plurality of light emitting elements that illuminate the original document via a placement transparent body are arranged in a main scanning direction, wherein the light emitting element among the plurality of light emitting elements emits light Lighting control means for controlling lighting and extinction for each element or each light emitting element block composed of a plurality of continuous light emitting elements, and a document size for detecting the size of the document placed on the document placing transparent body Detecting means, and the open / close detection. When the lighting control means turns on the light emitting element or the light emitting element block prior to the image reading operation of the original when the means detects that the original pressing member is closed, the original size detection is performed. Based on the detection result of the size of the original detected by the means, the light emitting element or the light emitting element block in the light source unit by the lighting control means, the light emitting element or the light emitting element in the original area corresponding to the size of the original. Provided is an image reading apparatus characterized in that a light emitting element block is turned on, and the light emitting elements or light emitting element blocks other than the document area are turned off. The present invention also provides an image forming apparatus comprising the image reading apparatus according to the present invention.

  According to the present invention, when the light emitting element or the light emitting element block is turned on by the lighting control unit prior to the image reading operation of the document, the detection result of the size of the document detected by the document size detecting unit. The lighting control means turns on the light emitting element or the light emitting element block in the document area corresponding to the size of the document among the light emitting element or the light emitting element block in the light source unit while the lighting control unit Since the light emitting element or the light emitting element block is turned off, it is possible to reduce the amount of protrusion of the light source that protrudes outside the original placed on the original placing transparent body and emits light. Can make the operator feel dazzled by the light from the light source regardless of the viewing direction of the light source. That. In addition, the light from the light source can be blocked by the original placed on the original placing transparent body, so that the operator feels dazzled by the light from the light source that protrudes outside the original. It is possible to surely reduce the occurrence.

  In the present invention, it is preferable that a light amount control means for controlling a light emission amount of the light emitting element or the light emitting element block is provided. In this configuration, when the opening / closing detection unit detects that the document pressing member is closed, the lighting control unit turns on the light emitting element or the light emitting element block prior to the image reading operation of the document. For example, the light amount control unit may control the light emission amount of the light emitting element or the light emitting element block to be smaller than the light emission amount when reading the image of the document.

  In this specific matter, since the light emission amount of the light emitting element or the light emitting element block is made smaller than the light emission amount when the image of the original is read, even if the original placed on the original placement transparent body is Even if light leaks to the outside, the amount of light emitted from the light-emitting element or light-emitting element block can be reduced to such an extent that it is difficult for the operator to feel dazzling, thereby further reducing the operator from feeling dazzling by the light from the light source. It becomes possible to make it.

  In the present invention, a document presence / absence detecting unit that detects whether or not the document is placed on the document placing transparent body, and a light amount control unit that controls a light emission amount of the light emitting element or the light emitting element block. In the configuration provided, when the document detection member detects that the document pressing member is closed, the document detection unit detects whether the document is placed on the document placement transparent body. When it is detected that the light emitting element or light emitting element block is lit by the lighting control means prior to the image reading operation of the original, the light quantity control means causes the light emitting element or light emitting element to be lit. A mode in which the light emission amount of the block is controlled to be smaller than the light emission amount when reading the image of the original can be exemplified.

  In this specific matter, when the document is not placed on the document placing transparent body, the light emission amount of the light emitting element or the light emitting element block is smaller than the light emission amount when reading the image of the document. Therefore, the light emission amount of the light emitting element or the light emitting element block in a state where the original is not placed on the original placement transparent body can be set to a light quantity that is difficult to feel dazzling to an operator, and thereby the original. However, when it is not placed on the original placing transparent body, it is possible to reduce the glare of the operator due to the light from the light source.

In this embodiment, the following specific embodiment (a) and embodiment (b) can be employed. That is,
Aspect (a) is a case where the opening / closing detection means detects that the document pressing member is closed, and the document is detected on the document placement transparent body by the document presence / absence detection means. When it is detected that the light emitting element or the light emitting element block is turned on by the lighting control means prior to the image reading operation of the document, the light emitting element or the light emitting element block is turned on. It is an aspect.

  In this specific matter, when the original is not placed on the original placement transparent body, the light emission amount of the light emitting element or the light emitting element block is smaller than the light emission amount when reading the image of the original. Therefore, even if all of the light emitting elements or the light emitting element blocks are turned on because there is no original (the size of the original cannot be detected), it is possible to reduce glare to the operator.

  Aspect (b) is a case where the opening / closing detection means detects that the document pressing member is closed, and the document is detected on the document placement transparent body by the document presence / absence detection means. When it is detected that the light emitting element or the light emitting element block is to be turned on by the lighting control means prior to the image reading operation of the original document, a part of the light emitting element or the light emitting element block is turned on. It is an aspect to make it.

  In this specific matter, when the original is not placed on the original placement transparent body, the light emission amount of the light emitting element or the light emitting element block is smaller than the light emission amount when reading the image of the original. Further, by lighting a part of the light emitting element or the light emitting element block, the number of the light emitting element or the light emitting element block to be turned on can be reduced, and it can be reduced that the operator feels dazzling.

  In the present invention, the original placed on the original placing transparent body is scanned in the main scanning direction while moving the light source portion in the sub-scanning direction, and the image is passed through the original placing transparent body. When reading the original image of the white reference member and the white reference member provided in an area other than the reading area of the original in the moving area in which the light source moves. A mode provided with storage means for storing a reference reading value serving as a reference for the above can be exemplified. In this aspect, the document presence / absence detecting means may be provided. In the configuration including the light amount control means for controlling the light emission amount of the light emitting element or the light emitting element block, when the open / close detection means detects that the document pressing member is closed, the document When the presence / absence detection means is provided, the document opening / closing detection means detects that the document pressing member is closed, and the document presence / absence detection means detects that the document is transparent for placing the document. When it is detected that the light-emitting element or the light-emitting element block is turned on by the lighting control means prior to the reading operation of the image of the original when it is detected that it is placed on the body, the light-emitting element or the light-emitting element block The light source unit is moved to the white reference member side in a state where the light source is turned on, the white reference member is read by the image reading unit, the read value of the read white reference member, and the storage The light emission amount of the light emitting element or the light emitting element block that emits light when the image reading of the original is read by the light amount control means based on the comparison result compared with the reference reading value stored in advance in the stage It is preferable to perform the light amount correction control.

  In this specific matter, the read value of the white reference member obtained by reading the white reference member with the image reading unit is compared with the reference read value stored in advance in the storage unit, and the comparison result is compared. On the basis of the above, since the light amount correction control of the light emission amount of the light emitting element or the light emitting element block that emits light when the image of the original is read by the light amount control unit is performed, the light amount correction control can be reliably performed. In the case where the document presence / absence detecting means is provided, the light amount correction control can be reliably performed when the document is placed on the document placing transparent body.

  In the present invention, the light source section that includes a document reading transparent body for reading a document and that is transported in the sub-scanning direction so as to pass over the document reading transparent body is located at the reading position. Scanning in the main scanning direction is configured to be read by the image reading unit via the original reading transparent body, and the original reading transparent body is defined as the reading area with the white reference member interposed therebetween. The aspect provided in the other side can be illustrated. In this aspect, when the open / close detection unit detects that the document pressing member is closed, the lighting control unit turns on the light emitting element or the light emitting element block prior to reading the document image. When the light source unit is moved toward the document reading transparent body, the white reference member is irradiated with light from the light emitting element or the light emitting element block and the white reference member is read by the image reading unit, A mode in which the light emitting element or the light emitting element block is turned off before the light source unit reaches the original reading transparent body can be exemplified.

  In this specific matter, since the light emitting element or the light emitting element block is turned off before the light source unit reaches the document reading transparent body, the light from the light source is used by the operator in an area corresponding to the document reading transparent body. It is possible to avoid dazzling.

  The image reading apparatus according to the present invention includes a plurality of mirrors and lenses, guides the reflected light from the document to the lens by the mirror, and functions as a photoelectric conversion element by the lens. It may be a reduction optical system type image reading apparatus that forms a reduced image and reads it. Examples of the photoelectric conversion element used in the reduction optical system type image reading apparatus include a solid-state imaging element such as a charge coupled device (CCD).

  An image reading apparatus according to the present invention includes a lens array, and a contact image sensor (CIS) that acts as a photoelectric conversion element in a lens array close to the document for reflecting light from the document. It may be an equal magnification optical system type image reading apparatus that forms and reads a double image.

  As described above, according to the present invention, when the light-emitting element or the light-emitting element block is turned on by the lighting control unit prior to the image reading operation of the document, a part of the light-emitting element or the light-emitting element block is used. Since the light source is turned on, it is possible to reduce the amount of protrusion of the light source, thereby reducing the operator from feeling dazzled by the light from the light source regardless of the direction of viewing the light source.

1 is a cross-sectional view schematically illustrating an image forming apparatus including an image reading apparatus according to an embodiment of the present invention. It is a schematic sectional drawing of the image reading apparatus shown in FIG. It is a figure which shows schematic structure of a light source unit, Comprising: (a) is the perspective view, (b) is the disassembled perspective view. FIG. 4 is a schematic perspective view for explaining an open / close detection configuration of the automatic document feeder, and is a view of the state in which the automatic document feeder is open with respect to the document reading unit as viewed obliquely from the upper front. FIG. 4 is a schematic side view for explaining an open / close detection configuration of the automatic document feeder, and is a view of the open / close state of the automatic document feeder as viewed from the left side. 4A and 4B are schematic configuration diagrams of an open / close detection unit provided in the document reading unit, where FIG. 4A is a cross-sectional view of the open / close detection unit, and FIG. 4B is a bottom view of the open / close detection unit viewed from below. . It is the schematic perspective view which looked at the image reading device concerning this embodiment from the front slanting upper part. FIG. 2 is a diagram showing a schematic configuration of a control system of the image reading apparatus according to the present embodiment, and is a control block diagram mainly showing a control unit in the image reading apparatus. 2A and 2B are diagrams for explaining determination of the size and presence / absence of a document, in which FIG. 1A is a schematic plan view of an arrangement configuration of document size sensors as viewed from above, and FIG. FIG. 4C is a table showing a setting table representing the presence / absence of light reception by the light receiving unit of the document presence / absence sensor. It is a figure for demonstrating an example of the lighting and light extinction pattern of a light emitting element or a light emitting element block based on the detection result of a document size, Comprising: The positional relationship of the light emitting element on a light source board | substrate in a light source and the size of a document is shown. It is a schematic plan view. It is a figure for demonstrating an example of the lighting and light extinction pattern of a light emitting element or a light emitting element block based on the detection result of the document size, Comprising: The table | surface which shows the setting table showing lighting and light extinction of a light emitting element or a light emitting element block It is. 4 is a flowchart illustrating an example of operation control by a main control unit of the image reading apparatus.

  Embodiments according to the present invention will be described below with reference to the drawings. The following embodiments are examples embodying the present invention, and are not of a nature that limits the technical scope of the present invention.

[Overall Configuration of Image Forming Apparatus]
FIG. 1 is a cross-sectional view schematically showing an image forming apparatus D provided with an image reading apparatus 100 according to an embodiment of the present invention.

  An image forming apparatus D shown in FIG. 1 reads an image of an original G (see FIG. 2 described later) and an image of the original G read by the image reading apparatus 100 or an image received from the outside. An apparatus main body Dd that records and forms a recording sheet P such as a recording sheet in color or single color is provided. The apparatus main body Dd includes an image forming unit 51 and a sheet conveyance system 52.

  The image forming unit 51 includes an exposure unit 1, a plurality of developing units 2, a plurality of photosensitive drums 3, a plurality of cleaning units 4, a plurality of chargers 5, an intermediate transfer belt unit 6, a plurality Toner cartridge units 21... And a fixing unit 7.

  The sheet conveyance system 52 includes a paper feed tray 81, a manual paper feed tray 82, and a discharge tray 91.

  A document reading apparatus 100 including a document reading unit 200 is provided on the upper part of the apparatus main body Dd. The document reading unit 200 is incorporated in the apparatus main body Dd. In the apparatus main body Dd, the entire image of the original read by the original reading section 200 of the original reading apparatus 100 is sent as image data to the apparatus main body Dd of the image forming apparatus D, and is formed based on the image data in the apparatus main body Dd. The recorded image is recorded on the recording sheet P.

  The image data handled in the image forming apparatus D corresponds to a color image using a plurality of colors (here, black (K), cyan (C), magenta (M), and yellow (Y)). Therefore, the developing unit 2,..., The photosensitive drum 3,..., The cleaning unit 4,. A plurality of (here, four are provided, each being black, cyan, magenta, and yellow) so as to be formed, and a plurality of (here, four) image stations are configured by these.

  The chargers 5,... Are charging means for uniformly charging the surface of the photosensitive drums 3,... To a predetermined potential. In addition to the charger type as shown in FIG. A type charger can be used.

  The exposure unit 1 is configured as a laser scanning unit (LSU) including a laser emitting unit and a reflection mirror. The exposure unit 1 is provided with a polygon mirror that scans a laser beam, and optical elements such as lenses and mirrors for guiding the laser beam reflected by the polygon mirror to the photosensitive drums 3. In addition to this, as the exposure unit 1, for example, a method using a writing head in which light emitting elements such as EL (electroluminescence) and LED (light emitting diode) are arranged in an array can be employed.

  The exposure unit 1 exposes the charged photoconductive drums 3... According to the input image data, so that an electrostatic latent image corresponding to the image data is displayed on the surface of each photoconductive drum 3. To form.

  The toner cartridge units 21,... Are units that contain toner, and are supplied to the developing tanks of the developing units 2,. In the apparatus main body Dd of the image forming apparatus D, the toner supplied from the toner cartridge units 21 to the developing tanks of the developing units 2 is controlled so that the toner density of the developer in the developing tank is constant. .

  The developing units 2... Visualize the electrostatic latent images formed on the respective photosensitive drums 3 with toners of four colors (Y, M, C, K). Further, the cleaning units 4... Remove and collect toner remaining on the surface of the photosensitive drums 3... After development and image transfer.

  The intermediate transfer belt unit 6 disposed above the photosensitive drums 3,... Has an intermediate transfer belt 61 that acts as an intermediate transfer member, an intermediate transfer belt drive roller 62, an intermediate transfer belt driven roller 63, and a plurality of intermediate transfer rollers. 64, and an intermediate transfer belt cleaning unit 65.

  Four intermediate transfer rollers 64,... Are provided corresponding to each color of Y, M, C, and K. The intermediate transfer belt drive roller 62 stretches the intermediate transfer belt 61 together with the intermediate transfer belt driven roller 63 and the intermediate transfer rollers 64, and is driven to rotate, whereby the intermediate transfer belt 61 moves in the direction of movement (arrow in FIG. 1). In the M direction, the driven roller 63 and the intermediate transfer rollers 64,.

  Each intermediate transfer roller 64,... Is applied with a transfer bias for transferring the toner image formed on the photosensitive drum 3,.

  The intermediate transfer belt 61 is provided so as to come into contact with the respective photosensitive drums 3. The intermediate transfer belt 61 forms a color toner image (multicolor toner image) on the surface by sequentially transferring the toner images of the respective colors formed on the photosensitive drums 3. The intermediate transfer belt 61 is, for example, endless using a film having a thickness of about 100 μm to 150 μm.

  Transfer of the toner image from the photosensitive drums 3 to the intermediate transfer belt 61 is performed by intermediate transfer rollers 64 that are in contact with the back side of the intermediate transfer belt 61. A high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (-)) is applied to the intermediate transfer rollers 64,... The intermediate transfer roller 64,... Is based on a metal (for example, stainless steel) shaft having a diameter of 8 mm to 10 mm, and the surface thereof is a conductive elastic material (for example, a resin material such as EPDM (ethylene-propylene-diene rubber) or urethane foam). It is the roller covered with. The intermediate transfer rollers 64,... Serve as transfer electrodes that uniformly apply a high voltage to the intermediate transfer belt 61 by the conductive elastic material. In this embodiment, a roller-shaped transfer electrode is used as the transfer electrode, but a transfer electrode such as a brush can be used in addition to this.

  As described above, the toner images visualized in accordance with the respective hues on the respective photosensitive drums 3 are stacked on the intermediate transfer belt 61. The toner images stacked on the intermediate transfer belt 61 are transferred by the transfer roller 10 constituting the secondary transfer mechanism unit disposed at the contact position between the recording sheet P and the intermediate transfer belt 61 by the circumferential movement of the intermediate transfer belt 61. Transferred onto the recording sheet P. However, the configuration of the secondary transfer mechanism is not limited to the transfer roller, and a transfer configuration such as a corona charger or a transfer belt can be used.

  At this time, the transfer roller 10 is in a state where a transfer nip is formed with the intermediate transfer belt 61, and a voltage for transferring the toner onto the recording sheet P (a polarity opposite to the toner charging polarity (-) (+ )) Is applied. A transfer nip is formed between the transfer roller 10 and the intermediate transfer belt 61 by the transfer roller 10 and the intermediate transfer belt driving roller 62 being pressed against each other. In order to obtain the transfer nip constantly, one of the transfer roller 10 and the intermediate transfer belt driving roller 62 is a hard roller made of a hard material (metal or the like), and the other is a soft material (elastic rubber or foam). The elastic roller is made of a resin material such as a functional resin.

  When the toner image is transferred from the intermediate transfer belt 61 onto the recording sheet P by the transfer roller 10, the toner may remain on the intermediate transfer belt 61 without being transferred onto the recording sheet P. The toner remaining on the intermediate transfer belt 61 causes toner color mixing in the next step. For this reason, the toner remaining on the intermediate transfer belt 61 is removed and collected by the intermediate transfer belt cleaning unit 65. Specifically, the intermediate transfer belt cleaning unit 65 includes a cleaning member (for example, a cleaning blade) that contacts the intermediate transfer belt 61. The driven roller 63 supports the intermediate transfer belt 61 from the inner side (back side), and the cleaning member is in contact with the intermediate transfer belt 61 so as to be pressed toward the driven roller 63 from the outer side.

  The paper feed tray 81 is a tray that previously stores recording sheets P on which images are formed (printed), and is provided below the exposure unit 1 in the apparatus main body Dd. A recording sheet P on which an image is formed (printed) is placed on the manual paper feed tray 82. The discharge tray 91 is provided above the image forming unit 51 in the apparatus main body Dd, and stacks the recording sheets P on which image formation (printing) has been performed face-down.

  Further, the apparatus main body Dd is provided with a sheet conveyance path S for sending the recording sheet P sent from the paper feed tray 81 and the manual paper feed tray 82 to the discharge tray 91 through the transfer roller 10 and the fixing unit 7. It has been. In the vicinity of the sheet conveyance path S, pickup rollers 11a and 11b, a plurality of (here, first to fourth) conveyance rollers 12a to 12d, a registration roller 13, a transfer roller 10, a heat roller 71 in the fixing unit 7, and a pressure are applied. A roller 72 and a discharge roller 31 are disposed.

  The first to fourth transport rollers 12 a to 12 d are small rollers for promoting and assisting the transport of the recording sheet P, and are provided along the sheet transport path S. The pickup roller 11 a is provided in the vicinity of the sheet supply side of the paper feed tray 81, picks up the recording sheets P one by one from the paper feed tray 81, and supplies them to the sheet conveyance path S. Similarly, the pickup roller 11 b is provided in the vicinity of the sheet supply side of the manual sheet feed tray 82, picks up the recording sheets P one by one from the manual sheet feed tray 82, and supplies them to the sheet conveyance path S.

  Further, the registration roller 13 temporarily holds the recording sheet P being conveyed through the sheet conveyance path S. Then, the registration roller 13 conveys the recording sheet P to the transfer roller 10 at a timing when the leading edge of the toner image on the intermediate transfer belt 61 and the leading edge of the recording sheet P are aligned.

  The fixing unit 7 fixes an unfixed toner image on the recording sheet P, and includes a heat roller 71 and a pressure roller 72 that act as a fixing roller. The heat roller 71 is driven to rotate so as to convey the recording sheet P while sandwiching the recording sheet P together with the pressure roller 72 that is driven to rotate. The heat roller 71 is heated by a heater 71a provided on the inner side, and is maintained at a predetermined fixing temperature based on a signal from the temperature detector 71b. The heat roller 71 heated by the heater 71a melts, mixes, and presses the multicolor toner image by thermally pressing the multicolor toner image transferred onto the recording sheet P together with the pressure roller 72 to the recording sheet P. The recording sheet P is thermally fixed. The fixing unit 7 is provided with an external heating belt 73 for heating the heat roller 71 from the outside.

  In the image forming apparatus D configured as described above, when single-sided printing is requested for the recording sheet P, the recording sheet P supplied from each of the paper feed trays 81 and 82 is provided along the sheet conveyance path S. Then, the toner image is conveyed to the registration roller 13 by the first conveying roller 12a and conveyed by the transfer roller 10 at a timing when the leading edge of the recording sheet P and the leading edge of the toner image on the intermediate transfer belt 61 are aligned. Transcribed. Thereafter, the recording sheet P passes through the fixing unit 7, whereby unfixed toner on the recording sheet P is melted and fixed by heat, and is discharged onto the discharge tray 91 through the second conveyance roller 12 b and the discharge roller 31.

  When double-sided printing is requested for the recording sheet P, the trailing end of the recording sheet P that has passed the fixing unit 7 after completion of the above-described single-sided printing is the discharge roller 31 and the branch portion Sa of the sheet conveying path S. When the discharge roller 31 rotates in the reverse direction, the recording sheet P is guided to the third and fourth transport rollers 12c and 12d. Then, the recording sheet P conveyed to the transfer nip via the registration roller 13 is printed on the back surface and then discharged to the discharge tray 91.

  1, reference numeral 201a (original table glass), reference numeral 203 (mirror unit), reference numeral 204 (condensing lens), reference numeral 205 (photoelectric conversion element), reference numeral 210 (light source unit), reference numeral 300 (automatic). The document feeder will be described in the next section “Overall Configuration of Image Reading Apparatus”.

[Overall configuration of image reading apparatus]
FIG. 2 is a schematic sectional view of the image reading apparatus 100 shown in FIG. An image reading apparatus 100 shown in FIGS. 1 and 2 is a reduction optical system type image reading apparatus, which reads a document image by fixing a document G by a document fixing method and reads a document G by a document moving method. The document image is moved and read.

  In other words, the image reading apparatus 100 includes a document fixed reading configuration (document fixed reading function) for executing the document fixed reading mode and a document moving reading configuration (document moving reading function) for executing the document moving reading mode.

  In the original fixed reading configuration, a light source unit (an example of a light source unit) 210 is moved in the sub-scanning reading direction Y1, and an original G placed on an original platen glass (an example of an original placement transparent body) 201a is converted into a light source. The unit 210 illuminates through the document table glass 201a, scans the reflected light from the illuminated document G in the main scanning direction X, and reads the image of the document G. In FIG. 2, before the light source unit 210 reads the image of the document G, the light source unit 210 is set to any one of the standby positions V1 corresponding to the reading area α of the document G (specifically, a predetermined position below the document table glass 201a). The position is shown.

  In the document moving reading configuration, the automatic document feeder 300 that automatically transports the document G automatically scans the document G that is transported in the transport direction Y3 so as to pass over the document scanning glass (an example of a document reading transparent body) 201b. The reflected light from the original G illuminated by the light source unit 210 is scanned in the main scanning direction X while the original reading unit 200 illuminates the original G through the original reading glass 201b at the light source unit 210 located at the reading position V2 of the original G. The image of the original G is read.

  Specifically, the document reading unit 200 includes a document table glass 201a, a light source unit 210, an optical system driving unit 530 that moves the light source unit 210 (not shown in FIGS. 1 and 2; see FIG. 8 described later), and a mirror unit 203. A condensing lens 204 and a photoelectric conversion element (an example of an image reading unit) 205 such as a CCD. These members are accommodated in a frame 202. The light source unit 210 includes a light source 211 that irradiates light toward the original G, and a first mirror 230 that guides reflected light from the original G to the mirror unit 203. The light source unit 210 will be described in detail later.

  The document table glass 201 a on which the document G is placed is made of a transparent glass plate, and both end portions in the main scanning direction X are placed on the frame body 202. The automatic document feeder 300 functions as a document pressing member and has a document pressing plate 319. The document pressing plate 319 is provided on the lower surface member 300a of the automatic document feeder 300, and presses the document G placed on the document table glass 201a from above. Instead of the automatic document feeder 300, only the document pressing plate may be used.

  The mirror unit 203 includes a second mirror 203a, a third mirror 203b, and a support member (not shown). The support member supports the second mirror 203a so that the light from the first mirror 230 in the light source unit 210 is reflected and guided to the third mirror 203b. Further, the support member supports the third mirror 203b so that the light from the second mirror 203a is reflected and guided to the condenser lens 204. The condensing lens 204 condenses the light from the third mirror 203b on the light receiving surface 205d of the photoelectric conversion element 205. The photoelectric conversion element 205 repeatedly scans light (original image light) from the condenser lens 204 in the main scanning direction X, and outputs an analog signal of one scanning line each time.

  The optical system driving unit 530 (see FIG. 8) includes a scanner motor (not shown) and a moving mechanism such as a pulley and a wire (not shown). The light source unit 210 is fixed by the scanner motor and the moving mechanism. The mirror unit 203 is configured to reciprocate in the sub-scanning direction Y at a moving speed that is ½ of the moving speed of the light source unit 210.

  Here, the document reading unit 200 is compatible with a document moving method in addition to a document fixing method, and includes a document reading glass 201b. Accordingly, the optical system driving unit 530 is further configured to position the light source unit 210 at the reading position V2 (home position) of the original G on the lower side of the original reading glass 201b.

  The automatic document feeder 300 includes a document tray 301 for placing the document G, a discharge tray 302 disposed below the document tray 301, a transport path 303 connecting them, and an upstream side. Two conveyance roller pairs including a conveyance roller pair 304 and a downstream conveyance roller pair 305 are provided.

  The upstream side conveyance roller pair 304 conveys the original G on the upstream side in the conveyance direction Y3 of the original G with reference to the original reading glass 201b. The downstream conveying roller pair 305 conveys the document G on the downstream side in the conveyance direction Y3 of the document G with reference to the document reading glass 201b. That is, the upstream conveyance roller pair 304, the document reading glass 201b, and the downstream conveyance roller pair 305 are arranged in this order along the conveyance direction Y3. Further, the document reading glass 201b is provided substantially horizontally so as to define the transport wall of the transport path 303.

  The automatic document feeder 300 further includes a pickup roller 306, a roller roller 307, a separation member 308 such as a separation pad, and a discharge roller pair 310.

  The pickup roller 306 feeds the document G placed on the document tray 301 from the document tray 301 into the transport path 303 along the transport direction Y3. The suction roller 307 is disposed downstream of the pickup roller 306 in the conveyance direction Y3, and further conveys the document G sent by the pickup roller 306 together with the separating member 308 to the downstream side of the conveyance direction Y3. It is. The separating member 308 is configured to scoop (separate) the original G so that the original G conveyed between the separating roller 307 and the reverse roller 307 is one sheet.

  In the automatic document feeder 300 having such a configuration, the document G is conveyed between the separating roller 307 and the separating member 308 by the pickup roller 306, and the document G is separated by being separated and the separating roller 307 is rotationally driven. As a result, the sheets are conveyed one by one. The original G conveyed by the roller roller 307 is guided along the conveyance path 303 and is supplied one by one toward the upstream conveyance roller pair 304.

  Specifically, the pickup roller 306 can be brought into and out of contact with the original G loaded on the original tray 301 by a pickup roller driving unit (not shown). The pickup roller 306 is connected to the roller roller 307 so as to rotate in the same direction as the roller roller 307 via a drive transmission means 309 including an endless belt. When a request for reading the document G is made, the pickup roller 306 and the roller 307 are rotationally driven in a direction (arrow W in FIG. 2) in which the document G is transported in the transport direction Y3 by a document supply driving unit (not shown). It has become.

  The conveyance path 303 is formed in a loop shape so that the document G is conveyed from the suction roller 307 to the discharge tray 302 via the upstream conveyance roller pair 304, the document reading glass 201b, the downstream conveyance roller pair 305, and the discharge roller pair 310. Yes. The discharge roller pair 310 is arranged on the downstream side in the transport direction Y3 with respect to the downstream side transport roller pair 305, and discharges the original G from the downstream side transport roller pair 305 to the discharge tray 302. The conveyance system rollers such as the conveyance roller pairs 304 and 305 and the discharge roller pair 310 are driven by a conveyance system drive unit (not shown).

  In the present embodiment, the automatic document feeder 300 further includes a document guide member (specifically, a document guide plate) 318 that defines the placement position of the document G in the sub-scanning direction Y. The document guide member 318 is provided between the document table glass 201a and the document reading glass 201b. In other words, the document reading glass 201b is provided on the side opposite to the reading region α with the document guide member 318 interposed therebetween. The document guide member 318 regulates the movement of the document G placed on the document table glass 201a in the direction Y2 opposite to the sub-scanning reading direction Y1, and here, the amount of light of the entire light source 211 is controlled. It also serves as a white reference member for reading when correcting the light level for raising and lowering the level. The white reference member (specifically, the white reference sheet) 318 a is provided in an area other than the reading area α of the document G in the movement area of the light source unit 210. Specifically, the white reference member 318 a is attached to the lower surface of the document guide member 318. Here, the white reference member 318a is also read when performing shading correction.

  Note that reference numerals 200a (upper surface member of the document reading unit 200), reference numeral 212 (light emitting element), and reference numeral 213 (substrate) attached in FIG. 2 will be described later.

  In the image reading apparatus 100 described above, when an instruction to read the original G by the original fixing method is given, the light source unit 210 moves from the standby position V1 and below the white reference member 318a in the original guide member 318. After the light quantity level is corrected, the original G placed on the platen glass 201a is irradiated with light through the platen glass 201a at a constant speed in the sub-scanning reading direction. At the same time, the mirror unit 203 moves in the sub-scanning reading direction Y1 at a moving speed that is half the moving speed of the light source unit 210.

  The reflected light that is illuminated by the light source unit 210 and reflected from the original G is reflected by the first mirror 230 provided in the light source unit 210 and then 180 ° by the second and third mirrors 203 a and 203 b of the mirror unit 203. The optical path is changed. The light reflected from the third mirror 203b forms an image on the light receiving surface 205d of the photoelectric conversion element 205 via the condenser lens 204, where the original image light is read and converted into an analog signal.

  On the other hand, when an instruction to read the original G by the original movement method is given, the light source unit 210 moves from the standby position V1 to the lower side of the white reference member 318a in the original guide member 318, and a light amount level correction process is performed. After that, the document G is further moved to the reading position V2 of the document G, and the document G is conveyed in the conveyance direction Y3 by the automatic document feeder 300 so as to pass above the reading position V2 while being stationary at the reading position V2. In other words, the original G placed on the original tray 301 is taken out by the pickup roller 306, separated one by one by the separating roller 307 and the separating member 308, and conveyed to the conveying path 303. The document G transported to the transport path 303 is aligned at the leading edge by the upstream transport roller pair 304 to prevent skew feeding, and is sent out at a specified reading timing, and the front and back are reversed, and the document G is moved to the document reading glass 201b. Be transported.

  Then, the light from the light source unit 210 is irradiated on the one surface of the original G that has passed over the original reading glass 201b through the original reading glass 201b, and is reflected on the one surface. The light reflected from one surface of the original G is reflected by the first mirror 230 in the same manner as the above-described original fixing method, and then the optical path is changed by 180 ° by the second and third mirrors 203a and 203b of the mirror unit 203. Then, an image is formed on the light receiving surface 205d of the photoelectric conversion element 205 via the condenser lens 204, and the original image is read and converted into an analog signal.

  The document G that has been read is pulled out from the document reading glass 201 b by the downstream conveyance roller pair 305, and is discharged onto the discharge tray 302 by the discharge roller pair 310 through the conveyance path 303.

  The image reading apparatus 100 according to the present embodiment may be an equal magnification optical system type image reading apparatus.

  FIG. 3 is a diagram illustrating a schematic configuration of the light source unit 210. FIG. 3 (a) shows a perspective view thereof, and FIG. 3 (b) shows an exploded perspective view thereof.

  The light source unit 210 according to the embodiment of the present invention irradiates light from a plurality of light emitting elements 212 arranged on a substrate (hereinafter referred to as a light source substrate) 213 toward the light irradiation surface Gd of the document G. It is like that.

  The light source 211 provided in the light source unit 210 includes a plurality of light emitting elements 212, and a light source substrate 213 on which the light emitting elements 212 are mounted. The plurality of light emitting elements 212,... Are all light emitting diode (LED) elements. Each light emitting element is of the same type.

  The plurality of light emitting elements 212,... Irradiate light toward a certain light irradiation region side extending in the main scanning direction X of the original G. This light irradiation area is the reading position of the original G.

  In the present embodiment, the plurality of light emitting elements 212,... Are arranged on both sides in the sub-scanning direction Y along the light irradiation surface orthogonal to the main scanning direction X with the light irradiation region in between. The plurality of light emitting elements 212,... Are arranged such that each optical axis is perpendicular to the main scanning direction X.

  Specifically, the plurality of light emitting elements 212,... Have a plurality of first light emitting elements 212a,... Arranged in the main scanning direction X on one side of both sides in the sub-scanning direction Y, and the other side. A plurality of second light emitting elements 212b,... Are arranged in the main scanning direction X. That is, the plurality of light emitting elements 212,... Are two rows, a first light emitting element array composed of first light emitting elements 212a,... And a second light emitting element array composed of a plurality of second light emitting elements 212b,. Is arranged.

  The light source substrate 213 includes first and second light source substrates 213a and 213b extending in the main scanning direction X. The plurality of first light emitting elements 212a,... Are mounted on the first light source substrate 213a, and the plurality of second light emitting elements 212b,.

  In the present embodiment, the light emitting element pitches (distances between element centers in the main scanning direction X) P of the plurality of first light emitting elements 212a,... And the plurality of second light emitting elements 212b,. It is said that the distance. Further, in the first light emitting element row and the second light emitting element row, the first light emitting elements 212a,... And the second light emitting elements 212b,... Are arranged so that the pitch positions are aligned (with the same pitch position configuration). Here, the first light emitting elements 212a,... And the second light emitting elements 212b,.

  More specifically, the light source unit 210 includes a light emitting element array unit 215 and a mirror base unit 216 provided with the light emitting element array unit 215.

  The light emitting element array unit 215 includes a first light emitting element 212a, ..., a first light source substrate 213a, a second light emitting element 212b, ..., a second light source substrate 213b, a first light source substrate 213a, and a second light source substrate 213b. And a base 214 provided with.

  Specifically, the first light source substrate 213a and the second light source substrate 213b are arranged on the base 214 so that the longitudinal direction is directed to the main scanning direction X. The base 214 fixes the first and second light source substrates 213a and 213b with fixing members SC such as screws at both ends in the main scanning direction X at a predetermined interval in the sub scanning direction Y. In this way, the first light emitting elements 212a,... And the second light emitting elements 212b,... Are arranged in line along the main scanning direction X on both sides in the sub scanning direction Y with the light irradiation region in between.

  The base 214 further has an opening (here, a slit) R extending along the main scanning direction X for allowing the reflected light from the document G to pass between the first light source substrate 213a and the second light source substrate 213b. Is formed. The slit R is disposed below the light irradiation area that is the reading position of the document G when the document is read. The first light emitting element array and the second light emitting element array are arranged on both sides of the slit R in the short direction.

  The mirror base unit 216 is provided with a first mirror 230 (see FIG. 3B). Specifically, the first mirror 230 is a mirror that guides the light reflected by the light irradiation surface of the original G to the second mirror 203a (see FIG. 2) of the mirror unit 203 through the slit R provided in the base 214. The base unit 216 is supported while being inserted through the opening 216a along the main scanning direction X.

  In the present embodiment, the plurality of first light emitting elements 212a,... And the plurality of second light emitting elements 212b,... Are arranged on the light source elements of the first light source substrate 213a and the second light source substrate 213b, respectively. Side emission that emits light is performed so that the optical axis is parallel to the surface. Specifically, the first light source substrate 213a on which the first light emitting elements 212a,... Are mounted, and the second light source substrate 213b on which the second light emitting elements 212b,. It is arranged in a “C” shape with the side opposite to the original G side opened so as to face the area side. Note that the light irradiation region is located between the first light source substrate 213a and the second light source substrate 213b.

  In the configuration of the light source unit 210 described above, the plurality of light emitting elements 212,... Are arranged on both sides in the sub-scanning direction Y with the light irradiation region in between, but may be arranged only on one side. In this case, the plurality of light emitting elements 212,... Are mounted on the light source substrate 213 arranged on one side in the sub-scanning direction Y with the light irradiation region interposed therebetween so that the optical axis is parallel to the arrangement surface. Side emission that emits light is performed. Specifically, the light source substrate 213 is inclined and arranged so that the direction of the optical axis is directed to the light irradiation region side.

  Further, regardless of whether the plurality of light emitting elements 212,... Are arranged on both sides or only on one side, the light is emitted so that the optical axis is perpendicular to the arrangement surface of the mounted light source substrate 213. The emitted top surface light may be emitted. In this case, when the first light emitting elements 212a,... And the second light emitting elements 212b,... Emit light from the top surface, the reverse side of the original G side opened so that the direction of the optical axis is directed toward the light irradiation area. The first light source substrate 213a and the second light source substrate 213b can be arranged in a “shape”. Note that the light irradiation region is located between the first light source substrate 213a and the second light source substrate 213b. In addition, when the light emitting elements 212,... Are arranged on only one side, the light source substrate 213 can be inclined so that the direction of the optical axis is directed to the light irradiation region side.

  Although the light emitting elements can be arranged and configured in this way, when the light emitting elements are arranged at the same pitch position configuration on both sides, the number of light emitting elements is smaller than that in the configuration in which the light emitting elements are arranged only on one side. The illuminance can be doubled by doubling.

  In addition, when the light emitting element emits one of side light emission and top surface light emission, a configuration in which side light emission is performed and a configuration in which top surface light emission are performed depending on the arrangement configuration of the components in the light source unit 210. By using them properly, the free space in the light source unit 210 can be used effectively.

[Automatic document feeder open / close detection configuration]
Next, the open / close detection configuration of the automatic document feeder will be described. FIGS. 4 and 5 are a schematic perspective view and a schematic side view, respectively, for explaining the open / close detection configuration of the automatic document feeder 300. FIG. 4 is a diagram showing the state in which the automatic document feeder 300 is open to the document reading unit 200 as viewed obliquely from above. FIG. 5 is a view of the open / close state of the automatic document feeder 300 viewed from the left side.

  As described above, in the document reading apparatus 100, the optical unit 210 for reading a document reciprocates in the sub-scanning direction Y below the document table glass 201a and the document reading glass 201b. Further, the automatic document feeder 300 is opened and closed with respect to the document reading unit 200 on the document reading glass 201b, so that the document G placed on the document table glass 201a is pressed by the document pressing plate 319. It has become.

  Specifically, the automatic document feeder 300 is attached to the document reading unit 200 so as to be pivotable by opening the front side, so that the document G can be placed manually by opening the document table glass 201a. It has become. That is, the document reading apparatus 100 can read the image of the document G automatically conveyed by the automatic document feeder 300 or the image of the document G placed on the document table glass 201a.

  Further, the automatic document feeder 300 reads the document on both sides of the width scanning direction Y (sub-direction) at the back side end portion in the main scanning direction X (depth direction) of the document reading unit 200 provided with the document table glass 201a. The part 200 can be opened and closed around a rotation axis along the width scanning direction Y. Thus, the automatic document feeder 300 presses the document G against the document table glass 201a by the document pressing plate 319 when it is closed with respect to the document table glass 201a. The pressing of the original G to the original platen glass 201a by the pressing plate 319 is released.

  Specifically, the automatic document feeder 300 is attached by a pair of rotating members (specifically hinge members) 610 and 610 on both sides in the sub-scanning direction Y on the back side of the document reading unit 200.

  The rotating members 610 and 610 are fixed to the fixing unit 611 and 611 provided on the side of the document reading unit 200 incorporated in the apparatus main body Dd, and are rotatable with respect to the fixing units 611 and 611, and an automatic document feeder. Rotating portions 612 and 612 provided on the 300 side. The fixing units 611 and 611 are fixed to the upper surface member 200a of the document reading unit 200 with a fixing member SC such as a screw, and the rotating units 612 and 612 are fixed to the lower surface member 300a of the automatic document feeder 300 with screws or the like. It is fixed by the member SC.

  The image reading apparatus 100 further includes an operation unit (specifically, an operation panel) 230 provided on the front side of the document reading unit 200. The operation unit 230 includes an input unit 240, and various setting information of the entire apparatus and information for operating each function are input through the input unit 240. Here, the input unit 240 has a plurality of input keys (hardware keys) 241 and is a key input operation unit that can be operated by an operator such as a user. The operation unit 230 also functions as an operation unit of the image forming apparatus D.

  The operation unit 230 includes a display unit 250, and the display unit 250 displays the input content and the operation status of the entire apparatus. The display unit 250 is a display panel having a display screen capable of displaying output information. Here, the display screen of the display unit 250 is provided with a touch panel that receives an operator's input. This touch panel functions as an input unit.

  The image reading apparatus 100 further includes an open / close detection unit 260 (an example of an open / close detection unit) that detects whether or not the automatic document feeder 300 is closed with respect to the document reading unit 200.

[About the open / close detector]
FIG. 6 is a schematic configuration diagram of the open / close detection unit 260 provided in the document reading unit 200. FIG. 6A shows a cross-sectional view of the open / close detection unit 260. FIG. 6B shows a bottom view of the open / close detection unit 260 as viewed from below.

  As shown in FIG. 6, the open / close detection unit 260 includes an actuator unit 261, a detected unit 262 provided in the actuator unit 261, and a sensor unit 263 that detects the detected unit 262.

  As shown in FIG. 6A, the actuator portion 261 is movable along the vertical direction Z and is given an upward biasing force. Specifically, the actuator unit 261 is elongated in the vertical direction Z and has a bar-shaped open / close detection lever 261a whose upper end is in contact with the automatic document feeder 300, and a stopper unit 261b provided on the open / close detection lever 261a. A biasing member 261c (specifically, a compression spring) for biasing the open / close detection lever 261a upward, and a support portion 261d (specifically, an open / close detection lever mounting plate) for supporting the biasing member 261c. have.

  The upper surface member 200 a of the document reading unit 200 is provided with a through hole 200 b along the vertical direction Z. In addition, the support portion 261d is fixed to the frame body 202 (see FIG. 2) of the document reading portion 200 with a space below the upper surface member 200a. The support portion 261d is provided with a through hole 261e so as to be aligned in the vertical direction Z with respect to the through hole 200b.

  The open / close detection lever 261a is inserted through a through hole 200b provided in the upper surface member 200a of the document reading unit 200 and a through hole 261e provided in the support unit 261d so as to be movable in the vertical direction Z. A stopper 261b is fixed to the open / close detection lever 261a. The stopper portion 261b fixed to the open / close detection lever 261a is disposed between the upper surface member 200a and the support portion 261d. The stopper portion 261b is larger than the through holes 200b and 261e, and cannot pass through the through holes 200b and 261e. Thereby, the stopper part 261b can control the movement of the open / close detection lever 261a in the vertical direction Z.

  A biasing member 261c is disposed between the stopper portion 261b and the support portion 261d. Specifically, the urging member 261c is supported by the support portion 261d while being inserted into the open / close detection lever 261a, thereby urging the stopper portion 261b upward.

  The detected portion 262 protrudes in a direction perpendicular to the axial direction of the opening / closing detection lever 261a at a position lower than the support portion 261d of the opening / closing detection lever 261a (specifically, at the lower end portion of the opening / closing detection lever 261a). Yes.

  As shown in FIG. 6B, the sensor unit 263 is here a transmission type optical sensor including an irradiation unit 263a and a light receiving unit 263b. The sensor unit 263 is fixed to the frame 202 of the document reading unit 200 with an interval below the support unit 261d. The sensor unit 263 blocks or passes the incident light incident on the light receiving unit 263b from the irradiation unit 263a by the detected unit 262 by moving the detected unit 262 as the actuator unit 261 moves up and down. Presence / absence is detected by the light receiving unit 263b. The sensor unit 263 is connected to the input system of the main control unit 410 (see FIG. 8). The sensor unit 263 may be a reflection type optical sensor.

  In the present embodiment, the open / close detection unit 260 is configured such that the document pressing plate 319 of the automatic document feeder 300 is at a predetermined angle θ with respect to the upper surface member 200a of the document reading unit 200 (see FIG. 5, for example, 20 degrees to 30 degrees). Degree (more preferably, about 20 to 25 degrees) is detected (closing detection).

[Original Size Detection Unit]
FIG. 7 is a schematic perspective view of the image reading apparatus 100 according to the present embodiment as viewed obliquely from the front.

  As shown in FIG. 7, the image reading apparatus 100 further includes a document size detection unit 270 (an example of a document size detection unit) that detects the size of the document G. The document size detection unit 270 includes a plurality of document size sensors 271, 272, and 273, and is provided on the bottom surface of the document reading unit 200 (here, the surface 202a of the frame 202 facing the document table glass 201a). . The document size detection unit 270 is connected to the input system of the main control unit 410 (see FIG. 8).

  Specifically, the document size sensor 271 is an optical sensor that detects the size of the document G in the sub-scanning direction Y, and the document size sensors 272 and 273 are optical sensors that detect the size of the document G in the main scanning direction X. It is said that. The document size sensors 271, 272, and 273 are reflective optical sensors that detect reflected light from the document G. The document size sensors 271, 272, and 273 include irradiation units S1, S2, and S3 that irradiate predetermined light (for example, infrared light) and light receiving units R1, R2, and R3 that receive reflected light from the document G. ing.

[Document presence detection unit]
As shown in FIG. 7, the image reading apparatus 100 further includes a document presence / absence detection unit 280 (an example of a document presence / absence detection unit) that detects whether or not the document G is placed on the document table glass 201a. . The document presence / absence detection unit 280 includes a document presence / absence sensor 281 and is placed on the document table glass 201a on the bottom surface of the document reading unit 200 (here, the surface 202a facing the document table glass 201a of the frame 202). It is provided at a position where it can detect the original G of all sizes. The document presence / absence detection unit 280 is connected to the input system of the main control unit 410 (see FIG. 8).

  Specifically, the document presence / absence sensor 281 is an optical sensor that detects the presence / absence of a document G of all sizes. The document presence / absence sensor 281 is a reflective optical sensor that detects reflected light from the document G. The document presence / absence sensor 281 includes an irradiation unit S4 that emits predetermined light (for example, infrared light) and a light receiving unit R4 that receives reflected light from the document G.

[Control Configuration of Image Reading Apparatus]
FIG. 8 is a diagram showing a schematic configuration of a control system of the image reading apparatus 100 according to the present embodiment, and is a control block diagram mainly showing the control unit 400 in the image reading apparatus 100.

  As shown in FIG. 8, the image reading apparatus 100 according to the present embodiment further includes a control unit 400 that controls the entire image reading apparatus 100, a signal processing unit 510, and a storage unit 520 that functions as a storage unit. It has.

  The control unit 400 functions as a main control unit 410, a document reading control unit 420, an image processing unit 430, a light emitting element control unit 440, a light amount correction control unit 450 that functions as a light amount correction control unit, and a comparison unit. A comparison unit 460 and a drive control unit 470 are provided.

  When the document pressing plate 319 of the automatic document feeder 300 is open with respect to the upper surface member 200a of the document reading unit 200, the main control unit 410 opens the document pressing plate 319 from the sensor unit 263 in the open / close detection unit 260. A sensor output signal (specifically, an ON signal) indicating that light is being received is transmitted. On the other hand, when the document pressing plate 319 is closed with respect to the upper surface member 200a, the main control unit 410 outputs a sensor output signal (specifically) indicating that the document pressing plate 319 is closed (not receiving light) from the sensor unit 263. Specifically, an OFF signal) is transmitted. The main control unit 410 can detect the opening / closing of the document pressing plate 319 based on a sensor output signal (for example, an OFF signal or an ON signal) indicating that the document pressing plate 319 received from the sensor unit 263 is open or closed. It has become.

  Further, the main control unit 410 emits light from the irradiation units S1, S2, and S3 in the document size sensors 271, 272, and 273 to the document table glass 201a, and the document G is present on the document table glass 201a (light receiving unit R1). , R2 and R3 receive reflected light from the original G), sensor output signals (specifically, ON signals) indicating that the original G is present (received) from the light receiving portions R1, R2 and R3. ) Is sent. On the other hand, when there is no document G on the document table glass 201a (when the light receiving units R1, R2, and R3 do not receive the reflected light from the document G), the main control unit 410 receives the light from the light receiving units R1, R2, and R3. A sensor output signal (specifically, an OFF signal) indicating that there is no document G (no light is received) is transmitted. The main control unit 410 determines the size of the document G based on a sensor output signal (specifically, an ON signal or an OFF signal) indicating whether or not the document G is received from the light receiving units R1, R2, and R3. ing.

  Further, the main control unit 410 irradiates the document table glass 201a with light from the irradiation unit S4 in the document presence / absence sensor 281. When the document G exists on the document table glass 201a (the light receiving unit R4 transmits reflected light from the document G). When light is received), a sensor output signal (specifically, an ON signal) indicating that the original G is present (receives light) is transmitted from the light receiving unit R4. On the other hand, when there is no document G on the document table glass 201a (when the light receiving unit R4 does not receive the reflected light from the document G), the main control unit 410 does not have the document G from the light receiving unit R4. Sensor output signal (specifically, an OFF signal) is transmitted. The main control unit 410 detects the presence or absence of the document G based on a sensor output signal (specifically, an ON signal or an OFF signal) indicating whether or not the document G is received from the light receiving unit R4.

  The main control unit 410 includes a document reading control unit 420, an image processing unit 430, a light emitting element control unit 440, in addition to the sensor unit 263, document size detection unit 270, and document presence / absence detection unit 280 of the open / close detection unit 260 described above. The light amount correction control unit 450, the comparison unit 460, the drive control unit 470, the signal processing unit 510, and the storage unit 520 are connected.

  Specifically, the main control unit 410 includes a microcomputer including a processing unit 410a such as a CPU and a storage unit 410b including a memory such as a ROM and a RAM. In the image reading apparatus 100, the processing unit 410a of the main control unit 410 controls various components by loading a control program stored in advance in the ROM of the storage unit 410b onto the RAM of the storage unit 410b and executing it. It has become. The main control unit 410 is instructed by a control unit (not shown) that controls the entire image forming operation provided in the image forming apparatus D.

  The document reading control unit 420 controls the reading operation of the document G by the photoelectric conversion element 205 based on the instruction signal from the main control unit 410.

  The signal processing unit 510 is connected to the photoelectric conversion element 205, and processes a signal from the photoelectric conversion element 205 based on an instruction signal from the main control unit 410. Here, the signal processing unit 510 is an analog front end (AFE) IC, and performs various types of signal processing on an output signal (imaging signal) from the photoelectric conversion element 205. For example, the signal processing unit 510 amplifies an analog signal from the photoelectric conversion element 205 and converts the amplified analog signal into a digital signal (here, an 8-bit digital image signal).

  The image processing unit 430 performs various types of image processing on the A / D converted digital signal based on the instruction signal from the main control unit 410, and here, an ASIC (Application Specific Integrated Circuit) for image processing is used. ). Further, the image processing unit 430 performs shading correction when the image forming apparatus D is powered on. In the shading correction, the variation in the light amount in the main scanning direction X is corrected by the variation in the components of the light emitting elements 212 (1) to 212 (n) and the light collection characteristics of the optical system. Here, the shading correction is performed by making the digital signal A / D-converted based on the read value by the photoelectric conversion element 205 of the white reference member 318a in the document guide member 318 into a constant value.

  In this embodiment, the shading correction is performed when the image forming apparatus D is turned on. However, the shading correction may be performed when the closing is detected (every time the document pressing plate 319 is closed).

  The light emitting element control unit 440 is connected to the light emitting elements 212 (1) to 212 (n) in the light source 211, and based on an instruction signal from the main control unit 410, a plurality of light emitting elements 212 (1) to 212 (n). ) Can be individually driven for each light emitting element. Note that n is the number of light emitting elements, and is an integer of 6 or more here.

  Specifically, the light emitting elements 212 (1) to 212 (n) are connected in series, and terminals on both sides of the light emitting elements 212 (1) to 212 (n) connected in series are light emitting element control units 440. It is connected to the. The light emitting element control unit 440 is connected to the main control unit 410, and controls the on / off timing of each of the light emitting elements 212 (1) to 212 (n) for each light emitting element by an instruction signal from the main control unit 410. To do.

  The light emitting element control unit 440 includes a lighting control unit (an example of a lighting control unit) 441 that drives the individual light emitting elements 212 (1) to 212 (n), and the individual light emitting elements 212 (1) to 212 (n). A light amount control unit (an example of a light amount control unit) 442 that adjusts the light amount. Here, the lighting control unit is a light emitting element control driver.

  The lighting control unit 441 includes a plurality of continuous light emitting elements 212 (1) to 212 (i), 212 (i + 1) to 212 (j), and 212 (j + 1) for each of the light emitting elements 212 (1) to 212 (n). ˜212 (k), 212 (k + 1) ˜212 (l), 212 (l + 1) ˜212 (m), and 212 (m + 1) ˜212 (n) for each light emitting element block BL (1) ˜BL (h) (See FIGS. 10 and 11 to be described later) On / off control is performed. The subscripts i, j, k, l, and m of the reference numeral 212 are integers that satisfy the conditions of 1 ≦ i, i + 1 ≦ j, j + 1 ≦ k, k + 1 ≦ l, l + 1 ≦ m, and m + 1 ≦ n. The suffix h (number of blocks) of the code BL is an integer of 6 or more (6 blocks in the examples of FIGS. 10 and 11) here.

  Each light emitting element block may be divided so that the number of light emitting elements for each light emitting element block is equal, or the size (length) of the original G in the main scanning direction X as in the examples of FIGS. It may be divided for each). In particular, each light emitting element block is preferably divided so that the light emitting elements in the document area (including the vicinity of the document area) can be turned on and the areas other than the document area can be turned off.

  Here, the light quantity control unit 442 includes dimming circuits 442 (1),... 442 (n). The lighting control unit 441 is connected to the main control unit 410. Each light emitting element 212 (1) to 212 (n) has one terminal connected to the lighting control unit 441 and the other terminal a light amount control unit 442 (light control circuit 442 (1),..., 442 (n) ) Is connected to each.

  The light quantity control unit 442 (the dimming circuit 442 (1),... 442 (n)) is connected to the main control unit 410. Note that the light control circuit may be provided for each of the light emitting element blocks BL (1) to BL (h).

  The light amount correction control unit 450 is connected to the main control unit 410 on the input side and is connected to the light amount control unit 442 on the output side. The light amount correction control unit 450 performs light amount level correction at the time of closing detection by the open / close detection unit 260 (every time the document pressing plate 319 is closed). The light amount level correction corrects a change in the light amount with respect to a temporal change of the light emitting elements 212 (1) to 212 (n) or a light amount decrease due to temperature or the like. Here, the light amount level correction is performed by the light emitting elements 212 (1) to 212 (n) of the light amount control unit 442 so as to obtain a predetermined light amount based on the read value by the photoelectric conversion element 205 of the white reference member 318a in the document guide member 318. ) By controlling the voltage to. Note that the reference reading value Li of the white reference member 318a is a reference value for the amount of light emitted from the light source 211 that emits light when reading an image of the document G, and is stored in advance in the storage unit 520 (see FIG. 8). Yes. The reference reading value Li may be a measurement value measured for each image reading apparatus at the time of factory shipment, or may be a specified value standardized in design.

  Specifically, the light amount correction control unit 450 performs light amount correction control of the light emission amount of the light emitting elements 212 (1) to 212 (n) that emit light when reading the image of the document G based on the calculated value calculated by the comparison unit 460. Do.

  The comparison unit 460 reads the read value Ls by the photoelectric conversion element 205 of the white reference member 318a at the light emission amount of the light emitting elements 212 (1) to 212 (n) that emit light when reading the image of the document G, and the storage unit 520. The reference reading value Li stored in advance is compared. The light amount correction control unit 450 emits light when the light amount control unit 442 reads an image of the document G based on the comparison result, and the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (1) to BL. The light amount correction control of the emitted light amount of BL (h) is performed.

  Specifically, the main control unit 410 passes the read value Ls (for example, 8-bit digital value 200) and the reference read value Li (for example, 8-bit digital value 240) to the comparison unit 460. The comparison unit 460 calculates a ratio (for example, 240/200 = 1.2) of the reference reading value Li (for example, 240) to the received reading value Ls (for example, 200), and returns it to the main control unit 410. The main control unit 410 passes the received ratio (for example, 1.2) to the light amount correction control unit 450. The light amount correction control unit 450 is a light amount level obtained by multiplying the current light amount level (here, voltage) by the received ratio (for example, 1.2) with respect to the light emission amount of the light emitting elements 212 (1) to 212 (n). The light quantity control unit 442 is instructed to be (here, voltage).

  The drive control unit 470 controls the operation of the optical system drive unit 530 based on a reading command from the main control unit 410. That is, when a reading command is output from the main control unit 410 to the document reading control unit 420, the drive control unit 470 outputs a drive start signal to the optical system driving unit 530. The optical system drive unit 530 applies a drive voltage to a scanner motor (not shown) based on the drive start signal. The scanner motor is a drive source for the reciprocating movement of the scanner unit composed of the light source unit 210 and the mirror unit 203. As a result, the scanner motor rotates and the scanner unit reciprocates in the sub-scanning direction Y. In this embodiment, a stepping motor is used as the scanner motor.

  FIG. 9 is a diagram for explaining the determination of the size and presence of the document G. FIG. 9A shows a schematic plan view of the arrangement configuration of the document size sensors 271, 272, and 273 as viewed from above. FIG. 9B shows a setting table TL1 that indicates whether or not light is received by the light receiving portions R1, R2, and R3 of the document size sensors 271, 272, and 273. FIG. 9C shows a setting table TL2 that represents the presence or absence of light reception by the light receiving unit R4 of the document presence / absence sensor 281. In FIG. 9A, reference numerals B5 and A4 indicate a state in which the originals G of B5 size and A4 size are arranged so that the longitudinal direction is along the main scanning direction X, respectively. , A4R, B4, and A3 respectively show a state in which the originals G of B5 size, A4 size, B4 size, and A3 size are arranged so that the longitudinal direction is along the sub-scanning direction Y. The same applies to FIG. 10 described later.

  In the example shown in FIG. 9A, the document G placed on the document table glass 201a is positioned at the upstream end (left side in FIG. 9A) of the reading area α in the sub-scanning direction reading direction Y1 and in the main scanning direction. Positioning is performed with reference to both ends of X (upper side in FIG. 9A).

  As shown in FIG. 9B, the document size sensor 271 outputs a signal indicating that there is no document (not receiving light) at the light receiving unit R1 when the document G is in the arrangement state of B5R, B5, and A4. Further, in other arrangement states, the light receiving unit R1 is provided at a position to output a signal indicating that there is a document (receiving light). The document size sensor 272 is provided at a position for outputting a signal indicating that there is no document when the document G is in the arrangement state of B5R and A4R, and outputting a signal indicating that there is a document in other arrangement states. The document size sensor 273 is provided at a position for outputting a signal indicating that there is no document when the document G is arranged in the signs B5R, B5, B4, and A4R, and outputting a signal indicating that there is a document in other arrangement states. ing.

  The main control unit 410 can make the determination using the setting table TL1 shown in FIG. The setting table TL1 is stored in advance in the storage unit 520 (see FIG. 8).

  As shown in FIG. 9C, the document presence / absence sensor 281 indicates that there is a document if the document G is placed on the document table glass 201a regardless of the arrangement state of the document G. It is provided at a position for outputting a signal.

  The main control unit 410 can make the determination using the setting table TL2 shown in FIG. The setting table TL2 is stored in advance in the storage unit 520 (see FIG. 8).

  Note that the document size detection unit 270 can function as a document presence / absence detection unit for sizes other than the B5R size even when the document presence / absence detection unit 280 is not provided. The document size detection unit 270 may also serve as the document presence / absence detection unit by devising the detection pattern of the document size sensor so that the presence / absence of the document G of all sizes can be detected. This can be performed by a conventionally known method, and detailed description thereof is omitted here.

  By the way, as described above, the closing detection by the open / close detection unit 260 is set when the document pressing plate 319 has an angle θ (specifically, about 20 to 30 degrees) with respect to the upper surface member 200a. However, this is because the size and presence / absence of the original G can be detected even when the original G (book original) bound like a book is placed. That is, when the document pressing plate 319 is substantially closed or completely closed with respect to the upper surface member 200a (when the angle θ is about several degrees or 0 degrees), the detection is made in the case of a book document. This is because, since the document pressing plate 319 is in a slightly opened state, it should originally be detected in this state but may not be detected.

  As described above, when the document pressing plate 319 is slightly opened with respect to the upper surface member 200a when closing is detected, the light from the light source 211 enters the eyes of the operator via the document table glass 201a and the document reading glass 201b. Cheap.

  In the image reading apparatus 100 in the standby state, the light source unit 210 is in any position corresponding to the reading area α (see FIG. 2) of the original G (here, in the vicinity of the original guide member 318 below the original table glass 201a). It is stopped in a state where it is turned off at the standby position V1). When it is detected by the open / close detection unit 260 that the opened document pressing plate 319 is closed (closed detection), the standby position V1 is used to perform stable light quantity level correction using the closed detection as a trigger. While the light source 211 of the light source unit 210 located at is turned on, the original guide member 318 is moved to a position below the white reference member 318a. That is, in the image reading apparatus 100, when the document pressing plate 319 is detected as being slightly opened with respect to the upper surface member 200a (every time the document pressing plate 319 is closed), the lighting light of the light source 211 of the light source unit 210 is changed to the document pressing plate. 319 and the original platen glass 201a and the original reading glass 201b are likely to leak. This makes the operator feel dazzling.

  In this regard, when the main control unit 410 detects that the document pressing plate 319 is closed by the open / close detection unit 260, the lighting control unit 441 performs the light emitting element 212 ( 1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned on based on the detection result of the size of the original G detected by the original size detector 270. Among the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) in the light source unit 210, the light emitting elements 212 (1) to 212 (1) in the document area corresponding to the size of the document G (N) or the light emitting element blocks BL (1) to BL (h) are turned on, while the light emitting elements or light emitting element blocks other than the document area are turned off.

  According to the image reading apparatus 100 according to the present embodiment, the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (1) to the lighting control unit 441 prior to the image reading operation of the original G. When turning on BL (h), based on the detection result of the size of the original G detected by the original size detection unit 270, the lighting control unit 441 uses the light emitting elements 212 (1) to 212 (n) in the light source unit 210. Or, among the light emitting element blocks BL (1) to BL (h), the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) in the document area corresponding to the size of the document G. Is turned on, and the light emitting elements or light emitting element blocks other than the original area are turned off, so that the light emitting element 2 that emits light by protruding outside the original G placed on the original table glass 201a. 2 (1) to 212 (n) can be reduced, whereby the light source 211 that protrudes outside the original G placed on the original table glass 201a regardless of the direction in which the operator views the light source 211. It is possible to reduce the operator from feeling dazzled by the light from the light. In addition, since the light emitting elements or light emitting element blocks in the original area corresponding to the size of the original G are turned on based on the detection result of the size of the original G, the light emitting elements or light emitting element blocks other than the original area are turned off. Can be blocked by the original G placed on the platen glass 201a, thereby reliably reducing the operator from feeling dazzled by the light from the light source 211 protruding outside the original G. It becomes possible.

  When the opening / closing detection unit 260 detects that the document pressing plate 319 is closed, the lighting control unit 441 prior to the reading operation of the image of the document G causes the light emitting elements 212 (1) to 212 (n). Alternatively, when the light emitting element blocks BL (1) to BL (h) are turned on, the light source unit 210 is moved to the white reference member 318a side with the light emitting elements or the light emitting element blocks turned on, and the white reference member 318a is photoelectrically operated. A comparison is made by comparing the read value Ls of the white reference member 318a at the amount of light emitted when reading the image of the original G with the conversion element 205 and the reference read value Li stored in advance in the storage unit 520. Based on the result, the light amount control unit 442 performs light amount correction control of the light emission amount of the light emitting element or the light emitting element block that emits light when the image of the original G is read. By doing so, the light quantity correction control can be performed reliably. Further, when the open / close detection unit 260 detects that the document pressing plate 319 is closed, the document presence / absence detection unit 280 detects that the document G is placed on the document table glass 201a. In this case, by performing the light amount correction control, it is possible to reliably perform the light amount correction control when the document G is placed on the document table glass 201a.

  10 and 11 illustrate an example of lighting and extinguishing patterns of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) based on the detection result of the size of the original G. It is a figure for doing. FIG. 10 is a schematic plan view showing the positional relationship between the light emitting elements 212 (1) to 212 (n) on the light source substrate 213 and the size of the original G in the light source 211. FIG. 11 shows a setting table TL3 that represents lighting and extinguishing of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h). Note that the light emitting element block may include one light emitting element, but is illustrated as two or more in the example of FIG.

As shown in FIGS. 10 and 11, the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned on and off as follows. That is,
When the size of the original G is B5R, the light emitting elements 212 (1) to 212 (i) (light emitting element block BL (1)) and the light emitting elements 212 (j + 1) to 212 (n) (light emitting element block BL (3 ) To BL (6)) are turned off, and the light emitting elements 212 (i + 1) to 212 (j) (light emitting element block BL (2)) are turned on. When the size of the original G is A4R, the light emitting elements 212 (1) to 212 (i) (light emitting element block BL (1)) and the light emitting elements 212 (k + 1) to 212 (n) (light emitting element block BL (4 ) To BL (6)) are turned off, and the light emitting elements 212 (i + 1) to 212 (k) (light emitting element blocks BL (2) to BL (3)) are turned on. When the size of the original G is B5 or B4, the light emitting elements 212 (1) to 212 (i) (light emitting element block BL (1)) and the light emitting elements 212 (l + 1) to 212 (n) (light emitting element block BL) (5) to BL (6)) are turned off, and the light emitting elements 212 (i + 1) to 212 (l) (light emitting element blocks BL (2) to BL (4)) are turned on. When the size of the original G is A4 or A3, the light emitting elements 212 (1) to 212 (i) (light emitting element block BL (1)) and the light emitting elements 212 (m + 1) to 212 (n) (light emitting elements). The block BL (6)) is turned off, and the light emitting elements 212 (i + 1) to 212 (m) (light emitting element blocks BL (2) to BL (5)) are turned on. The setting table TL3 is stored in advance in the storage unit 520 (see FIG. 8).

  In the present embodiment, when the main control unit 410 detects that the document pressing plate 319 is closed by the open / close detection unit 260, the lighting control unit 441 emits light prior to the image reading operation of the document G. When the elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned on, the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL ( h) is configured to be controlled by the light amount control unit 442 so that the entire emitted light amount is smaller than the emitted light amount when the image of the original G is read.

  In the image reading apparatus 100 having such a configuration, the entire amount of light emitted from the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) is used for reading an image on the original G. Since the amount of emitted light is smaller than that of the light emitting element 212 (1) to 212 (n) or the light emitting element block BL (1) even if light leaks to the outside of the original G placed on the original table glass 201a. ) To BL (h) can be reduced to such an extent that it is difficult for the operator to feel dazzling, thereby further reducing the operator from feeling dazzled by the light from the light source 211.

  In the present embodiment, the main control unit 410 detects that the document pressing plate 319 is closed by the open / close detection unit 260, and the document presence / absence detection unit 280 detects that the document G is on the document table glass 201a. In the case where it is detected that the light source is not placed on the light emitting element 212 (1) to 212 (n) or the light emitting element block BL (1) to BL in the lighting control unit 441 prior to the image reading operation of the original G. When turning on (h), the light emission amount of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) is smaller than the light emission amount when reading the image of the original G. Thus, the light amount control unit 442 is configured to control.

  In the image reading apparatus 100 having such a configuration, when the document G is not placed on the platen glass 201a, the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL ( h) the amount of emitted light is smaller than the amount of emitted light when the image of the original G is read, so that the light emitting elements 212 (1) to 212 (n) in a state where the original G is not placed on the original table glass 201a. ) Or the light emission amount of the light emitting element blocks BL (1) to BL (h) can be set to such a level that it is difficult for the operator to feel dazzling. Thus, when the document G is not placed on the platen glass, the light source 211 It is possible to reduce the operator from feeling dazzled by the light from the light. In addition, when the image of the original G is not read because the original G is not placed on the platen glass 201a, the light amount correction control is performed, for example, after that, the image of the original G in the original moving reading mode. Even when the light amount correction control is not performed when reading the image, the image of the original G can be read with high accuracy by the corrected light amount at the time of closing detection (every time the original pressing plate 319 is closed).

  When the light emission amount of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) is made smaller than the light emission amount when reading the image of the document G, From the viewpoint of improving the correction accuracy, it is preferable to perform the following light amount correction control.

  In other words, the light amount correction control unit 450 reads the white reference member 318a by the photoelectric conversion element 205 with the light emission amount of the light emitting elements 212 (1) to 212 (n) smaller than the light emission amount when reading the image of the document G. When the value is Lc, the light amount correction control of the light emission amount of the light source 211 that emits light when reading the image of the original G is performed based on the calculated value calculated by the equation [(Lc / Ls) × Li]. Has been. Note that the read value Ls of the white reference member 318a at the amount of light emitted when reading the image of the document G is smaller than the amount of light emitted when reading the image of the document G when closing is detected (every time the document pressing plate 319 is closed). The white reference member 318a may be read when the read value Lc is read, or may be stored in the storage unit 520 (see FIG. 8) when the image of the original G is read.

  Specifically, the light amount correction control unit 450 replaces a reference read value Li (for example, 240) that serves as a reference for the light emission amount of the light emitting elements 212 (1) to 212 (n) that emit light when reading the image of the document G. The reference reading value Li and the reference reading value Lix for the low light quantity of the white reference member 318a with the light emission quantity of the light emitting elements 212 (1) to 212 (n) smaller than the light emission quantity when reading the image of the document G are used. The light amount correction control is performed using a calculated value (for example, 192) calculated by an equation [(Lc (for example, 8-bit digital value 160) / Ls (for example, 200)) × Li (for example, 240)] based on the read values Ls and Lc. It is configured.

  Specifically, the main control unit 410 passes the read value Lc (for example, 160) and the low light quantity reference read value Lix (for example, 192) to the comparison unit 460. The comparison unit 460 calculates the ratio (for example, 192/160 = 1.2) of the low light quantity reference read value Lix (for example, 192) to the received read value Lc (for example, 160), and returns it to the main control unit 410. The main control unit 410 passes the received ratio (for example, 1.2) to the light amount correction control unit 450. The light amount correction control unit 450 is a light amount level obtained by multiplying the current light amount level (here, voltage) by the received ratio (for example, 1.2) with respect to the light emission amount of the light emitting elements 212 (1) to 212 (n). To the light quantity control unit 442.

  In this way, in addition to the read value Lc with a light emission amount smaller than the light emission amount when reading the original G, the read value Ls when reading the image of the original G and the reference reading as a reference when reading the image of the original G By performing the light amount correction control using the value Li, for example, the light amount is smaller than when correcting using the light emission amount that is smaller than the light emission amount when reading the image of the original G and the corresponding reference read value. The correction accuracy of the correction control can be improved. In addition, by performing light amount correction control with a simple calculation formula such as [(Lc / Ls) × Li], the control configuration for light amount correction can be simplified accordingly.

  In the present embodiment, when the main control unit 410 detects that the document pressing plate 319 is closed by the open / close detection unit 260, the lighting control unit 441 emits light before the image reading operation of the document G. When the elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned on, the light emitting element 212 (1) is moved while moving the light source unit 210 toward the lower side of the document reading glass 201b. ) To 212 (n) or the light from the light emitting element blocks BL (1) to BL (h) is applied to the white reference member 318a to read the white reference member 318a with the photoelectric conversion element 205, and the light source unit 210 reads the original reading glass. The light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned off before reaching 201b.

  In the image reading apparatus 100 having such a configuration, the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned off before the light source unit 210 reaches the original reading glass 201b. Therefore, it is possible to avoid making the operator feel dazzled by the light from the light source 211 in the region corresponding to the document reading glass 201b.

  In the present embodiment, the open / close detection unit 260 detects that the document pressing plate 319 is closed, and the document presence / absence detection unit 280 places the document G on the document table glass 201a. If it is detected that the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are read by the lighting control unit 441 prior to the reading operation of the image of the original G. When the light is turned on, all of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) may be turned on. Thus, when the original G is not placed on the original table glass 201a, the light emission amount of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) is reduced. Since the amount of light emitted is smaller than the amount of light emitted when the image of the original G is read, there is no original G (the size of the original G cannot be detected), and thus the light emitting elements 212 (1) to 212 (n) or the light emitting element block BL (1) Even if all of BL (h) are turned on, it is possible to reduce the glare of the operator.

  In the present embodiment, the open / close detection unit 260 detects that the document pressing plate 319 is closed, and the document presence / absence detection unit 280 places the document G on the document table glass 201a. If it is detected that the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are read by the lighting control unit 441 prior to the reading operation of the image of the original G. When lighting, a part of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) may be lighted. Thus, when the original G is not placed on the original table glass 201a, the light emission amount of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) is reduced. Lights by turning on a part of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) in addition to the amount of light emitted when the image of the original G is read. The number of the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) to be made can be reduced, and it can be reduced that the operator feels dazzling.

[Example of operation control by the main control unit]
Next, a control example of operation control by the main control unit 410 of the image reading apparatus 100 will be described with reference to FIG.

  FIG. 12 is a flowchart illustrating an example of operation control by the main control unit 410 of the image reading apparatus 100. In this example, the read value Ls of the white reference member 318a at the amount of light emitted when reading the image of the document G is greater than when reading the image of the document G at the time of closing detection (every time the document pressing plate 319 is closed). The value read when reading the read value Lc of the white reference member 318a with a small amount of emitted light is used.

  In the control example shown in FIG. 12, first, opening / closing of the document pressing plate 319 is detected by the open / close detection unit 260 (step S1), and the document table is detected by the document presence / absence detection unit 280 based on the setting table L2 read from the storage unit 520. The presence or absence of the document G on the glass 201a is detected, and the document size detection unit 270 detects the size of the document G based on the setting table L1 read from the storage unit 520 (step S2).

  Next, when the original G exists on the original platen glass 201a (step S3: Yes), the process proceeds to step S6 through step S4. On the other hand, when the original G does not exist on the original table glass 201a (step S3). : No), the process proceeds to step S6 via step S5.

  In step S4, the light emitting elements or light emitting element blocks in the document area are turned on based on the setting table L3 read from the storage unit 520, and the light emitting elements or light emitting element blocks other than the document area are turned off.

  In step S5, since the original G is not placed on the original platen glass 201a and there is nothing to block the light emitted from the light source 211, light is emitted with a predetermined light emission amount smaller than the light emission amount when reading the image of the original G. All or part of the elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) are turned on.

  Here, if the amount of light emitted from the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) is too small, noise is generated with respect to the voltage when the white reference member 318a is read. Since the ratio increases, it becomes difficult to correct the light amount with high accuracy. Therefore, in consideration of both reduction of glare and correction accuracy, the predetermined amount of emitted light is preferably about 70% of the amount of emitted light when reading the image of the document G, for example.

  Next, the light source unit 210 located at the standby position V1 is moved to the white reference member 318a side with the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (h) turned on. (Step S6).

  In step S7, the reading value of the white reference member 318a (in the case of the light emission amount when reading the image of the original G, the read value Ls, and in the case of the light emission amount less than the light emission amount when reading the image of the original G). Is read by the photoelectric conversion element 205 to detect the light amount level. At this time, when the light emission amount is smaller than the light emission amount when reading the image of the original G, the photoelectric conversion element 205 also reads the read value Ls of the white reference member 318a at the light emission amount when reading the image of the original G. To detect the light level. Here, in the case where the light source unit 210 moves to the lower side of the document reading glass 201b, the light emitting elements 212 (1) to 212 (n) or the light emitting element blocks BL (1) to BL (BL) before reaching the document reading glass 201b. (H) may be turned off.

  Next, the reference reading value and the reading value are compared (step S8). Specifically, in step S8, in the case of the light emission amount when reading the image of the document G, the reference read value Li read from the storage unit 520 is compared with the read value Ls, or the image of the document G is compared. In the case of a light emission quantity that is smaller than the light emission quantity at the time of reading, the low light quantity reference read value Lix and the read value Lc calculated by the formula [(read value Lc / read value Ls) × reference read value Li] Compare

  Next, the light amount level (here, voltage) of the light source 211 is corrected (step S9), and the process is terminated.

DESCRIPTION OF SYMBOLS 100 Image reading apparatus 200 Original reading part 201a Original platen glass (an example of a document mounting transparent body)
201b Document reading glass (an example of a document reading transparent body)
204 Condensing lens 205 Photoelectric conversion element (an example of an image reading unit)
210 Light source unit (an example of a light source unit)
211 Light sources 212 (1) to 212 (n) Light emitting element 260 Open / close detection unit (an example of open / close detection means)
261 Actuator section 261a Open / close detection lever 261b Stopper section 261c Energizing member 262 Detected section 263 Sensor section 270 Document size detection section (an example of document size detection means)
271 to 273 Document size sensor 280 Document presence / absence detection unit (an example of document presence / absence detection means)
281 Document presence sensor 300 Automatic document feeder (an example of a document pressing member)
318 Document guide member 318a White reference member 319 Document holding plate 400 Control unit 410 Main control unit 420 Document reading control unit 430 Image processing unit 440 Light emitting element control unit 441 Lighting control unit (an example of lighting control means)
442 Light quantity control unit (an example of light quantity control means)
450 Light quantity correction control unit 460 Comparison unit 470 Drive control unit 510 Signal processing unit 520 Storage unit (an example of storage unit)
530 Optical system driving unit 610 Rotating member 611 Fixed unit 612 Rotating unit BL (1) to BL (h) Light emitting element block D Image forming apparatus G Document Lc Reading value Li Reference reading value Lix Low light quantity reference reading value Ls Reading Values R1 to R4 Light receiving portions S1 to S4 Irradiation portion V1 Standby position V2 Reading position X Main scanning direction Y Sub scanning direction θ Angle

Claims (9)

A document placement transparent body for placing a document;
A document pressing member configured to be openable and closable with respect to the document placement transparent body and configured to press the document placed on the document placement transparent body by being closed with respect to the document placement transparent body; ,
Open / close detecting means for detecting opening / closing of the document pressing member;
A light source unit having a light source in which a plurality of light-emitting elements that illuminate the document are arranged in the main scanning direction via the document placement transparent body to read an image of the document. ,
Among the plurality of light emitting elements, lighting control means for controlling lighting and extinction for each light emitting element or for each light emitting element block composed of a plurality of continuous light emitting elements;
Document size detecting means for detecting the size of the document placed on the document placing transparent body,
When the lighting control means turns on the light emitting element or the light emitting element block prior to the image reading operation of the original when the open / close detection means detects that the original pressing member is closed, Based on the detection result of the size of the original detected by the original size detecting means, the lighting control means in the light emitting element or the light emitting element block in the light source section of the original area corresponding to the original size. An image reading apparatus that turns on a light emitting element or a light emitting element block, and turns off the light emitting element or the light emitting element block other than the document area. The image reading apparatus according to claim 1,
A light amount control means for controlling the light emission amount of the light emitting element or the light emitting element block;
When the lighting control means turns on the light emitting element or the light emitting element block prior to the image reading operation of the original when the open / close detection means detects that the original pressing member is closed, An image reading apparatus, wherein a light amount control unit controls a light emission amount of the light emitting element or the light emitting element block to be smaller than a light emission amount when reading an image of the document. The image reading apparatus according to claim 1 or 2,
A document presence / absence detecting means for detecting whether or not the document is placed on the document placing transparent body;
A light amount control means for controlling the light emission amount of the light emitting element or the light emitting element block, and
When the opening / closing detection unit detects that the document pressing member is closed, the document presence / absence detection unit detects that the document is not placed on the document placement transparent body. In this case, when the light emitting element or the light emitting element block is turned on by the lighting control unit prior to the reading operation of the image of the original, the light amount of the light emitting element or the light emitting element block is An image reading apparatus that controls to reduce the amount of light emitted when reading an image of the document. The image reading apparatus according to claim 3,
When the opening / closing detection unit detects that the document pressing member is closed, the document presence / absence detection unit detects that the document is not placed on the document placement transparent body. In this case, when the light-emitting element or the light-emitting element block is turned on by the lighting control means prior to the image reading operation of the original, the light-emitting element or the light-emitting element block is turned on. Reader. The image reading apparatus according to claim 3,
When the opening / closing detection unit detects that the document pressing member is closed, the document presence / absence detection unit detects that the document is not placed on the document placement transparent body. In this case, when the light-emitting element or the light-emitting element block is turned on by the lighting control unit prior to the reading operation of the image of the document, a part of the light-emitting element or the light-emitting element block is turned on. Image reading device. The image reading apparatus according to claim 1 or 2,
The original placed on the original placing transparent body is scanned in the main scanning direction while the light source part is moved in the sub-scanning direction, and is read by the image reading section through the original placing transparent body. It is made up of
A light amount control means for controlling the light emission amount of the light emitting element or the light emitting element block;
A white reference member provided in a region other than the reading region of the original document in a moving region in which the light source unit moves;
Storage means for storing a reference reading value serving as a reference when reading the original image of the white reference member;
When the lighting control means turns on the light emitting element or the light emitting element block prior to the image reading operation of the original when the open / close detection means detects that the original pressing member is closed, With the light emitting element or light emitting element block turned on, the light source unit is moved to the white reference member side, the white reference member is read by the image reading unit, the read value of the read white reference member, and the storage The light emission amount of the light emitting element or the light emitting element block that emits light when the image of the original is read by the light amount control unit based on the comparison result compared with the reference reading value stored in advance by the unit An image reading apparatus that performs light amount correction control. An image reading apparatus according to any one of claims 3 to 5,
The original placed on the original placing transparent body is scanned in the main scanning direction while the light source part is moved in the sub-scanning direction, and is read by the image reading section through the original placing transparent body. It is made up of
A white reference member provided in a region other than the reading region of the original document in a moving region in which the light source unit moves;
Storage means for storing a reference reading value serving as a reference when reading the original image of the white reference member;
When the opening / closing detection unit detects that the document pressing member is closed, the document presence / absence detection unit detects that the document is placed on the document placement transparent body. In this case, when the light-emitting element or the light-emitting element block is turned on by the lighting control unit prior to the image reading operation of the document, the light source unit is turned on with the light-emitting element or the light-emitting element block turned on. The white reference member is moved to the white reference member side and read by the image reading unit, and the read value of the read white reference member is compared with the reference read value stored in advance in the storage unit, The light amount control unit performs light amount correction control of the light emission amount of the light emitting element or the light emitting element block that emits light when the image of the original is read by the light amount control unit based on the comparison result. Image reading device. The image reading apparatus according to claim 6 or 7,
A document reading transparent body for reading a document is provided,
The document transported in the sub-scanning direction so as to pass over the document-reading transparent body is scanned in the main scanning direction by the light source unit positioned at the reading position, and is passed through the document-reading transparent body. It is configured to read by the image reading unit,
The document reading transparent body is provided on the side opposite to the reading area with the white reference member interposed therebetween,
When the lighting control means turns on the light emitting element or the light emitting element block prior to the image reading operation of the original when the open / close detection means detects that the original pressing member is closed, The white reference member is read by the image reading unit by irradiating the white reference member with light from the light emitting element or the light emitting element block while moving the light source unit toward the document reading transparent body. An image reading apparatus, wherein the light emitting element or the light emitting element block is turned off before reaching the document reading transparent body.   An image forming apparatus comprising the image reading apparatus according to claim 1.

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