JP2007304193A - Original size detecting device, image reader and image forming apparatus using the detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an original size detecting device having simple constitution and achieving space saving, preventing a harness for a light source from deteriorating and being damaged due to the rubbing of the coating film thereof, providing stable irradiating light quantity and moreover, dispensing with a light source for detecting the original size and reducing the number of components. <P>SOLUTION: The original size detecting device 9 is mounted in the image reader 40A equipped with a scanner part 3 having an exposure lamp 3A, an optical lens body 6 and a CCD 7, and detects the size of the original G placed on the image reader 40A. The exposure lamp 3A is fixed on the body side of the image reader 40A. The device 9 is equipped with reflection plates 9a1, 9a2 and 9a3 reflecting irradiating light from the exposure lamp 3A; and light-receiving sensors 9b1, 9b2 and 9b3 receiving reflected light. The reflection plates 9a1, 9a2 and 9a3 are arranged at a plurality of spots, corresponding to the original size on the body side of the image reader 40A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a document size detection device, an image reading device using the same, and an image forming device, and more particularly to an image reading device that reads an image from a document placed on a document placement table and an image forming device using the same. About.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers, scanner apparatuses, and facsimile apparatuses are equipped with an image reading apparatus that optically scans and reads an image from a document.

  As a conventional technique for reading an image by such an image reading apparatus, the image reading apparatus is fixed at a predetermined position, and an original is moved along a transparent contact glass (platen glass) arranged at the position for reading the image. A method of reading an image with a scanner (image reading means) (hereinafter referred to as “original moving method”) and a method of reading an image while moving the scanner along a document fixed on the document table (hereinafter referred to as “document moving method”). For the sake of explanation, this will be roughly divided into “original fixing method”.

  An original reading apparatus based on the original moving system is equipped with an automatic original conveying apparatus (ADF) that stacks a plurality of originals and automatically supplies the originals one by one to the image reading apparatus to enable continuous image reading processing. In addition, by automatically discharging a document whose image has been read to a discharge tray, it is possible to continuously perform image reading processing and widely used in image forming apparatuses that support high-speed and large-volume processing.

  On the other hand, an image reading apparatus based on a document fixing method is not widely used as a document moving method in high-speed processing, but is generally widely used because it can be configured at a low cost with a simple structure.

  Here, a conventional image reading apparatus using a document fixing method will be briefly described with reference to the drawings. FIG. 13 is an explanatory diagram showing an example of the configuration of an image reading unit in a conventional image reading apparatus.

  As shown in FIG. 13, a conventional image reading apparatus 301 using a document fixing method includes a light source for irradiating a document on a mirror base 304 that reciprocates opposite to a document G placed on a document table 2 made of transparent glass. In general, 303 is fixed and power is supplied to the light source 303 by a harness 303A.

In the image reading by the document reading device 301, the document G is scanned while moving the mirror base 304, and the reflected light image of the document G irradiated by the light source 303 is guided to the 2.3 mirror 305 by the reflecting mirror 304C. The CCD 7 is irradiated and read by the reflection mirrors 305A and 305B in the mirror 305.
Reference numeral 7a in the figure denotes a document image reading unit in which the CCD 7 is housed integrally.

  However, when the original G is read, the light source 303 moves with the movement of the mirror base 304, so that there is a problem that the covering of the harness 303A is rubbed and deteriorated or damaged when operated for a long period of time. Moreover, in order to cope with the recent increase in speed, it is necessary to operate the mirror base 304 at a high speed, and it is necessary to take measures against the deterioration of the harness 303A.

  Therefore, a method of fixing the light source to the apparatus main body and irradiating the original with a traveling mirror-based reflecting plate is also conceivable. However, when the light is simply reflected by the mirror-based reflection plate, the amount of light changes depending on the distance between the light source and the reflection plate, so that there is a problem that an appropriate amount of light cannot be obtained.

In order to adjust the distance of the optical path length from the original to the target point as the traveling mirror base moves, the light source is fixed to the main body of the device and equipped with optical components that convert the light emitted from the light source into parallel light. Discloses a technique in which the second mirror base is moved (see Patent Documents 1 and 2).
JP 62-75628 A Japanese Patent Laid-Open No. 3-291164

  However, the conventional image reading apparatus has a problem that the configuration of the light source for irradiating the original and the configuration of the optical path for reliably irradiating the irradiation light are complicated, resulting in an increase in the size of the apparatus.

  Further, the above-described conventional image reading apparatus is usually provided with a document size detecting means for detecting the document size, and when reading an image, the size of the document to be read is detected and the image is read according to the document size. It is controlled to perform the operation.

  However, since the document size detection means requires a light source for document detection, there are problems that the number of components increases, the cost increases, and the size of the apparatus increases.

  The present invention has been made in view of the above-described conventional problems, and has a simple configuration and saves space, and obtains a stable irradiation light quantity without rubbing and damaging the sheath of the light source harness. In addition, an object of the present invention is to provide a document size detection apparatus that can reduce the number of parts by eliminating the need for a document size detection light source, and an image reading apparatus and an image forming apparatus using the document size detection apparatus.

The configuration of the image reading apparatus according to the present invention and the image forming apparatus using the same for solving the above-described problems is as follows.
The document size detection apparatus according to claim 1 is, for example, a so-called moving light reflecting unit that illuminates a document and that moves along the sub-scanning direction and irradiates a reading portion of the document with irradiation light from the light source. As an optical system for condensing image light reflected from a document illuminated by the light source, for example, an image reading device having a lens body and a photoelectric conversion element for reading the image light condensed by the lens body As a means, for example, a scanner is provided, mounted on an image reading apparatus that scans an original image line by line, converts it into an electrical signal by the photoelectric conversion element, and outputs the electric signal. A document size detection device for detecting a size, wherein the document size detection means is configured to reflect a reflection plate for reflecting light emitted from the light source and reflected by the reflection plate. A light receiving means for receiving light emitted from a light source, the light source is fixed to the image reading apparatus main body side, and the reflection plate is arranged at a plurality of locations corresponding to the document size on the image reading apparatus main body side. To do.

  The document size detection device according to claim 2 is characterized in that, in addition to the configuration described in claim 1, the light source can change the irradiation direction between when the document size is detected and when the document is irradiated. It is.

  According to a third aspect of the present invention, in addition to the configuration described in the first or second aspect, the document size detecting device includes a slit portion opened along the main scanning direction on the irradiation light emitting side of the light source. The portion is provided so as to be able to expand and contract in the height direction with respect to the document placement surface.

  In addition to the configuration described in any one of claims 1 to 3, the document size detecting device described in claim 4 is a position for irradiating the document with irradiation light from the light source. In this case, the irradiation light from the light source that is reflected by the reflecting plate and irradiates the original when the light is moved to is shielded.

  According to a fifth aspect of the present invention, in addition to the configuration described in any one of the first to fourth aspects, the document size detection device is configured such that the reflection plate is opposite to the document placement side with the moving reflection means interposed therebetween. It is characterized by being arranged on the side.

  A document size detection apparatus according to a sixth aspect is characterized in that, in addition to the configuration according to any one of the first to fifth aspects, an LED is used as the light source.

  According to a seventh aspect of the present invention, in addition to the configuration described in any one of the first to fifth aspects, the document size detection device uses a plurality of LEDs and a lens array as the light source. Is.

  The image reading apparatus according to claim 8 includes a light source that illuminates the document, a moving reflection unit that moves along a sub-scanning direction to irradiate light from the light source to a reading portion of the document, and the light source. An image reading means having an optical system for collecting image light reflected from the original illuminated by the optical system, a photoelectric conversion element for reading the image light condensed by the optical system, and an original size detecting device for detecting the original size And an image reading device that scans a document image line by line according to the document size, converts the image into an electrical signal by the photoelectric conversion element, and outputs the electrical signal. The image reading apparatus according to any one of the above is provided.

  The image forming apparatus according to claim 9 includes: a light source that illuminates the document; a moving reflection unit that moves along a sub-scanning direction to irradiate the reading portion of the document with the light from the light source; and the light source. An image reading means having an optical system for collecting image light reflected from the original illuminated by the optical system, a photoelectric conversion element for reading the image light condensed by the optical system, and an original size detecting means for detecting the original size In an image forming apparatus equipped with an image reading device that scans a document image line by line according to the document size, converts it into an electrical signal by the photoelectric conversion element, and outputs it, as the image reading device, The image reading apparatus according to claim 8 is provided.

  According to the first aspect of the present invention, the light source that illuminates the document, the mirror base that is a moving reflection unit that moves along the sub-scanning direction and irradiates the reading portion of the document with the light emitted from the light source, An original is provided with a scanner as an image reading means having a lens body as an optical system for condensing image light reflected from an original illuminated by a light source, and a photoelectric conversion element for reading out the image light condensed by the lens body. A document size detecting device that is mounted on an image reading device that scans an image line by line, converts the image into an electrical signal by the photoelectric conversion element, and outputs the electric signal, and detects the size of the document placed on the image reading device. The document size detecting means includes a reflecting plate that reflects the irradiation light from the light source, and a light receiving means that receives the irradiation light from the light source reflected by the reflecting plate. The light source is fixed to the image reading apparatus main body side, and the reflector is arranged at a plurality of locations corresponding to the document size on the image reading apparatus main body side, so that it is not necessary to move the light source together with the mirror base. The power supply harness can be prevented from being worn and damaged, and a stable amount of light can be obtained. In addition, the number of parts can be reduced by using the light source for document irradiation as a light source for document size detection. In addition, it is possible to realize a document size detection device that saves space.

  Moreover, according to invention of Claims 2-8, in addition to the said common effect obtained by the invention of Claim 1, the following effect can be acquired.

  That is, according to the invention described in claim 2, in addition to the effect obtained in the invention described in claim 1, the light source can be changed in the irradiation direction between the document size detection and the document irradiation. Thus, it is possible to effectively use the two light source and document detection functions with a single light source.

  According to the third aspect of the present invention, in addition to the effect obtained by the first or second aspect of the present invention, a slit portion opened along the main scanning direction is provided on the irradiation light emitting side of the light source. By providing the slit part so that it can be expanded and contracted in the height direction with respect to the document placement surface, the irradiation range of the irradiation light from the light source can be specified, so the irradiation light can be used effectively. can do.

  According to the invention described in claim 4, in addition to the effect obtained by the invention described in any one of claims 1 to 3, the moving reflection unit is configured to apply the irradiation light from the light source to the document. By blocking the irradiation light from the light source that is reflected by the reflecting plate and irradiates the document when it moves to the irradiation position, the light reflected by the reflecting plate does not irradiate the document. The photoelectric conversion element can be irradiated with appropriate image light from the document.

  According to the invention described in claim 5, in addition to the effect obtained by the invention described in any one of claims 1 to 4, the reflecting plate is placed on the original with the moving reflecting means interposed therebetween. By arranging it on the opposite side, a space-saving device configuration using dead space can be realized.

  According to the invention described in claim 6, in addition to the effect obtained by the invention according to any one of claims 1 to 5, the irradiation light is diffused by using the LED as the light source. Therefore, stable parallel light can be obtained without changing the amount of light regardless of the position of the moving reflection means.

  According to the invention described in claim 7, in addition to the effect obtained by the invention according to any one of claims 1 to 5, a plurality of LEDs and a lens array are used as the light source. Since the lens array can irradiate the irradiation light without diffusing it, stable parallel light can be obtained without diffusing the irradiation light.

  According to the invention described in claim 8, the light source that illuminates the document, the moving reflection means that moves along the sub-scanning direction and irradiates the reading portion of the document with the light source, and the light source An image reading means having an optical system for collecting image light reflected from the original illuminated by the optical system, a photoelectric conversion element for reading the image light condensed by the optical system, and an original size detecting device for detecting the original size And an image reading device that scans a document image line by line according to the document size, converts the image into an electrical signal by the photoelectric conversion element, and outputs the electrical signal. By providing the image reading apparatus according to any one of the above, it is possible to prevent the sheath of the light source harness from being rubbed and deteriorated and damaged, and to obtain a stable amount of irradiation light. Strive to reduce the number of parts by shared light source for irradiating a light source for detecting the document size, it can be realized an image reading apparatus which aimed to save space.

  According to the ninth aspect of the present invention, the light source that illuminates the document, the moving reflection means that moves along the sub-scanning direction and irradiates the reading portion of the document with the light from the light source, and the light source An image reading means having an optical system for collecting image light reflected from the original illuminated by the optical system, a photoelectric conversion element for reading the image light condensed by the optical system, and an original size detecting means for detecting the original size In an image forming apparatus equipped with an image reading device that scans a document image line by line according to the document size, converts it into an electrical signal by the photoelectric conversion element, and outputs it, as the image reading device, By providing the image reading device according to claim 8, it is possible to prevent the sheath of the light source harness from being rubbed and deteriorated and damaged, and to obtain a stable irradiation light quantity. Source strive to reduce the number of parts with be used also as a light source for detecting the document size of the use can be realized an image forming apparatus which aimed to save space.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
1 and 2 show an example of an embodiment of the present invention. FIG. 1 is a perspective view showing the overall configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 shows the inside of the image forming apparatus. It is side surface sectional drawing which shows this structure.

  The image forming apparatus 1 according to the present embodiment includes an image reading device 40A that reads image information of a document G. The image information of the document G read by the image reading device 40A is a predetermined recording medium that becomes a recording medium by an electrophotographic method. It is output and formed as a monochrome image on a sheet-like recording paper (hereinafter referred to as paper).

  As shown in FIGS. 1 and 2, the image forming apparatus 1 is provided with a document placing table (for example, platen glass) 2 made of transparent glass on which the document G is placed on the upper surface of the apparatus main body 1a. .

  An automatic document processing device 40 is provided above the document table 2, while a scanner unit (image reading means) constituting an image reading unit for reading image information of the document G is provided below the document table 2. ) 3 is arranged.

  The document placing table 2, the scanner unit 3, the automatic document processing device 40, and the like constitute an image reading device 40A.

  Below the scanner unit 3, an image forming unit 10, a fixing device 30, and a paper discharge unit 22 are configured. Further, below the scanner unit 3, a paper feed cassette 23 that stores recording paper as a recording medium is arranged. Yes.

  As shown in FIG. 2, the scanner unit 3 is formed of a rectangular box and an exterior portion is formed. The scanner unit 3 is mainly disposed below the document table 2 and is reciprocally moved in parallel. (Illuminating means) 4 and second scanning unit (optical path length adjusting means) 5, an optical lens body (optical system) 6, and a document image reading unit 7A including a CCD (photoelectric conversion element) 7 and an exposure lamp (light source). 3A.

  As shown in FIG. 2, the image forming unit 10 mainly includes a photosensitive drum 11 that is rotationally driven in the direction of an arrow, a main charger 12 that charges the surface of the photosensitive drum 11 to a predetermined potential, and a photosensitive member. A laser scanning unit 8 that irradiates the surface of the drum 11 with laser light for forming an electrostatic latent image, and the electrostatic latent image resulting from the laser light irradiation from the laser scanning unit 8 is developed with toner and visualized. Developing device 13 and a paper (corresponding to a “recording medium”) on which a toner image of a document image visualized by the developing device 13 is fed from a paper feed cassette 23 to be described later via a paper feed path 25. (Also referred to as “transfer sheet”) and a cleaning roller 15 for cleaning residual toner remaining on the photosensitive drum 11 after transfer by the transfer roller 14 and the transfer roller 14. They are arranged in order along a rotational direction of the body drum 11.

  The main charger 12 of the image forming unit 10 has a function of a static elimination device (not shown) that neutralizes charges on the surface of the photosensitive drum 11 after being cleaned by the cleaning device 15.

  As shown in FIG. 2, the fixing device 30 includes a heating roller 31 and a pressure roller 32, and rotates the heating roller 31 while the paper P is sandwiched between the heating roller 31 and the pressure roller 32. By passing between the heating roller 31 and the pressure roller 32, the toner image transferred onto the paper P is melted and fixed on the paper P.

  The sheet P after the toner image is transferred between the photosensitive drum 11 and the transfer roller 14 is peeled off from the photosensitive drum 11 to connect the photosensitive drum 11 and the fixing device 30 to each other. The toner enters between the heating roller 31 and the pressure roller 32 of the fixing device 30 via the conveyance path 16. A nip portion is formed at a contact portion between the heating roller 31 and the pressure roller 32 by a predetermined pressing force.

  In the fixing device 30, the sheet P sandwiched between the heating roller 31 and the pressure roller 32, that is, the nip portion, is heated on the sheet P by the heating roller 31 and the pressure applied by the pressure roller 32. The unfixed toner image transferred from the drum 11 is fixed.

The sheet P after being fixed by the fixing device 30 is conveyed to the sheet discharge conveyance path 17 and is conveyed by the sheet discharge drive roller 18 toward the sheet discharge roller 19 on the sheet discharge port 20 side.
The sheet P conveyed to the paper discharge conveyance path 17 is detected by the fixing detection switch 21A in a state where the sheet P passes between the heating roller 31 and the pressure roller 32 provided on the downstream side of the fixing device 30. The

  In the case of normal single-sided printing, the paper is discharged from the paper discharge port 20 onto the paper discharge tray 22a installed in the lower space of the scanner unit 3 by the rotational drive of the paper discharge drive roller 18 and the paper discharge roller 19 as it is. Thus, the passage state of the paper P by the paper discharge roller 19 is detected by a paper discharge detection switch 21B provided on the upstream side of the paper discharge roller 19.

  The paper P is discharged to the side of the image forming unit 10, and the discharged paper P is discharged above the paper feeding cassette 23 and below the scanner unit 3.

  On the inner bottom side of the apparatus main body 1a, a replaceable sheet cassette 23 in which sheets P are stacked and stored for each predetermined sheet size is disposed. A half-moon-shaped paper pick-up roller 24 is disposed on the paper discharge side upper portion of the paper feed cassette 23.

The paper pick-up roller 24 picks up the paper P stacked and accommodated in the paper feed cassette 23 one by one from the uppermost layer, and moves toward the downstream side (for convenience, the flow side (cassette side) of the paper P is upstream and discharged). The paper is conveyed to a registration roller (also referred to as an “idle roller”) 26 in the paper feed conveyance path 25 (with the paper side as the downstream side).
In the drawing, symbol Pa indicates a front end portion of the paper P, and Pb indicates a rear end portion of the paper P.

  A pre-registration detection switch 21 </ b> C is provided on the upstream side of the registration roller 26, and this pre-registration detection switch 21 </ b> C detects the paper P conveyed and fed from the paper feed cassette 23. The paper is fed to the above-described image forming unit 10 while timing the paper feeding based on the signal.

  In the case of performing double-sided printing, after the single-sided printing of the paper P by the image forming unit 10, the paper P after passing from the fixing device 30 conveyed to the paper discharge conveyance path 17 is temporarily disposed on the paper discharge roller 19 side. In this state, the sheet switching gate 27 disposed in the vicinity of the fixing device 30 is controlled to be switched, and the sheet P is switched back by the reverse rotation driving of the sheet discharge roller 19 and introduced into the sub-conveying path 28 where the sheet is reversed. Then, by rotating the sub drive roller (reversing roller) 29 provided in the sub transport path 28, the paper P is transported again to the upstream side of the registration roller 26, whereby the other side printing of the paper P is performed. ing.

  On the document table 2 of the apparatus main body 1a, an automatic document processing device 40 integrated with a document pressing portion (document pressing cover) 51a composed of a double-sided document automatic reading device (R-SPF) by a document moving method can be opened and closed. The image reading device 40A is configured together with the scanner unit 3.

  The image reading device 40A can perform original document reading processing for each sheet by the same operation as that of the conventional machine. By installing the automatic document processing device 40, both sides of the original G can be read. Automatic continuous reading processing of a plurality of documents G is possible.

  As shown in FIG. 2, the automatic document processing apparatus 40 has a document tray 41 on which the document G is placed. When reading a plurality of documents G continuously, the automatic document processing device 40 is placed on the document tray 41. The original G is picked up by the original pickup roller 42, and the original G is introduced into the original conveyance path 44 via the original driving roller 43 so as to be guided and conveyed upstream of the registration roller (PS roller) 45. It has become.

  An upstream side of the PS roller 45 is provided with a document insertion sensor 46 for detecting the document size of the document G. The document insertion sensor 46 detects the leading edge and the trailing edge of the document G, and While controlling the conveyance timing based on the signal, conveyance of the original G onto the original reading table 101 made of slit glass arranged adjacent to one side of the original placing table 2 is controlled.

  In this case, the first scanning unit 4 of the scanner unit 3 is controlled to move so as to stand by below the original reading table 101.

As the document G conveyed on the document reading table 101 is moved, the first image reading surface G1 on one side is scanned by the first scanning unit 4 of the scanner unit 3 at the image reading position. At this image reading position, a contact glass 102 for making the distance between the document and the scanner unit 3 uniform is provided.
Other image forming processes such as reading by the CCD 7, image processing of image information, and printing are the same as described above.

Then, the original G after image reading on the contact glass 102 is conveyed to the original discharge roller 49 side of the original discharge path 48 via the conveyance roller 47.
When only single-sided reading is performed, the document is switched onto the document discharge tray 51 by switching control of the document switching gate 50.

  On the other hand, when performing double-sided image reading, the document G is once discharged onto an intermediate tray 52 disposed between the document tray 41 and the document discharge tray 51 by switching control of the document switching gate 50. Then, the document discharge roller 49 is reversely driven to be switched back so as to be introduced into the document reversing path 53, and again, the document G is transported to the document transport path 44, so that the image reading surface G 2 on the back side of the document G is The original image is read, and the original image on the back side of the original G is printed on the first print surface P1 of the paper P in the same manner as the single-side printing process described above.

  When the printing process of the paper P on the first printing surface P1 is completed, the paper P is reversed by the paper reversing mechanism described above, and is again conveyed to the image forming unit 10, and is transferred to the first printing surface P2. A document image on the front side of the document G stored in the memory in advance is printed.

  As shown in FIG. 1, on the front side of the upper part of the apparatus main body 1a in the image forming apparatus 1, the user can select the type of the paper P (paper size, paper thickness, etc.), the number of printed sheets, the magnification, and the density. Operation switches 76 for setting image forming conditions such as these are provided.

The paper discharge unit 22 mainly includes a paper discharge conveyance path 17, a paper discharge drive roller 18, a paper discharge roller 19, a paper discharge port 20, and a paper discharge tray 22a.
A paper stacking amount detection sensor 21D, also called a full detection sensor, is provided outside the paper discharge port 20 (on the paper discharge tray 22a side).

  The sheet stacking amount detection sensor 21D is mainly configured by a detection body 21D1 that operates when discharged and stacked sheets abut and a sensor body 21D2 that outputs a signal in accordance with the operation of the detection body 21D1. Yes.

  The detection body 21D1 has a rod shape, one end is engaged with the sensor body 21D2, the other end is swingably provided with the one end serving as a fulcrum, and the outer side from the apparatus side (the discharge port 20 side). It is arranged so as to be opposed and inclined obliquely downward.

  The sheet stacking amount detection sensor 21D receives a detection signal from the sensor body 21D2 by pushing up the other end of the detection body 21D1 when the discharged sheet is stacked and reaches a predetermined amount (height). It is designed to output.

Next, the configuration of the sheet conveyance path that constitutes the image forming apparatus of the present embodiment will be described.
As shown in FIG. 2, the sheet conveying path of the image forming apparatus 1 mainly includes a sheet feeding conveyance path 25 that conveys sheets upward from a sheet feeding cassette 23 provided at the lower part of the apparatus, and the image forming unit 10. A main conveyance path 16 that conveys the sheet from the image forming unit 10 through the fixing device 30 to the sheet discharge drive roller 18, and a sheet discharge conveyance path 17 that conveys the sheet from the sheet discharge drive roller 18 to the sheet discharge roller 19. The paper feed roller 19 is reversely driven, and the reverse conveyance path 28 is configured to switch back the paper P by the reverse roller 29 and reverse the paper.

  The paper feed conveyance path 25 is provided with a roller (not shown) for separating the paper one by one when the paper is double-fed in the paper conveyance direction downstream of the paper pickup roller 24 in the paper conveyance direction. The resist roller 26 provided close to the lower side (upstream side in the paper conveyance direction) of the photosensitive drum 11 is gently curved and provided substantially linearly.

  The main conveyance path 16 is formed substantially linearly from the downstream side of the registration roller 26 through the image forming unit 10 to the fixing device 30, and is discharged from the outlet side (downstream side in the paper conveyance direction) of the fixing device 30 substantially upward. A curved portion 16a curved toward the paper driving roller 18 (left direction in the figure) is provided.

  The paper discharge conveyance path 17 is provided substantially linearly between the paper discharge drive roller 18 and the paper discharge roller 19. The paper discharge driving roller 18 includes a first transport roller 18 a that transports the paper to the paper discharge transport path 17 and a second transport roller 18 b provided in the middle of the paper discharge transport path 17. The configuration of the paper discharge drive roller 18 is not limited to this.

  The sub-transport path 28 communicates with the curved portion 16a of the main transport path 16 by switching the sheet switching gate 27 so that the paper P is switched back by the reverse rotation driving of the paper discharge roller 19 and conveyed. The sheet P is configured to be conveyed below the apparatus by the reversing roller 29 and conveyed to the registration roller 26 again.

  Specifically, the sub-conveying path 28 includes a first curved portion 28a for changing the direction of the paper P conveyed in the reverse direction from the paper discharge conveying path 17 and the paper P conveyed below the apparatus. And a second curved portion 28b for changing the direction on the registration roller 26 side.

  As the reversing roller 29 provided in the sub-conveying path 28, a first reversing roller 29a and a second reversing roller 29b are provided on the upstream and downstream sides of the sheet conveying direction with the first bending portion 28a interposed therebetween, and the second bending portion 28b. A third reverse roller 29c is provided on the upstream side in the paper conveyance direction with a gap therebetween, and a fourth reverse roller 29d is provided on the downstream side.

Here, the characteristic configuration of the scanner unit according to the present embodiment will be described in detail with reference to the drawings.
FIG. 3 is an explanatory diagram showing an example of the configuration of the scanner unit constituting the image reading device mounted on the image forming apparatus, FIG. 4 is an explanatory diagram showing the configuration of the exposure lamp constituting the scanner unit, and FIG. FIG. 6 is an explanatory diagram showing the positional relationship between the reflector and the light receiving sensor constituting the document size detecting device. FIG. 6 is an explanatory diagram showing the configuration of the reflecting plate constituting the document size detecting device arranged in the scanner unit.

  As shown in FIG. 3, the scanner unit 3 includes a first scanning unit 4, a second scanning unit 5, an optical lens body 6, an original image reading unit 7A having a CCD 7, and an exposure lamp 3A. Is provided.

  As shown in FIG. 4, the exposure lamp 3A includes a light source 3A1, a condenser (hereinafter referred to as a reflector) 3A2, a first optical lens body 3A3, and a second optical lens body 3A4. As shown, the first scanning unit 4 and the second scanning unit 5 are positioned at one end side inside the main body of the scanner unit 3, at a position facing the end portion side of the first scanning unit 4 in the main scanning direction. Irradiation is directed toward the first scanning unit 4 that is provided in a region that does not interfere with the above-described operation and moves along the sub-scanning direction of the scanner unit 3.

For example, a fluorescent lamp tube is used as the light source 3A1 as a cold cathode ray tube that is long in the main scanning direction.
The reflector 3A2 surrounds the outer periphery of the light source 3A1 along the longitudinal direction of the light source 3A1, and has an opening 3A21 extending in the sub-scanning direction and extending along the scanning direction.

  The exposure lamp 3A is attached so as to be tiltable, and its operation is controlled so that the irradiation direction can be changed between when the document size is detected and when the document is irradiated.

As shown in FIG. 3, a slit portion 3 </ b> B that is opened long along the main scanning direction of the scanner portion 3 is provided on the irradiation light emission side of the exposure lamp 3 </ b> A. The slit portion 3B is shrunk with a predetermined gap in the height direction with respect to the document placement surface when exposing a normal document, and the height with respect to the document placement surface when detecting the document size. It is configured to expand in the direction (downward in the figure).
In the drawing, the optical path of the irradiation light from the exposure lamp 3A to the original when reading the original image is indicated by a broken line, and the optical path of the image light from the original to the CCD 7 is indicated by an alternate long and short dash line.

  As shown in FIG. 3, the first scanning unit 4 includes reflection mirrors 4A and 4B and a first mirror 4C that reflect and emit light from the exposure lamp 3A toward the document G. While maintaining a constant distance with respect to the lower surface of the mounting table 2, reciprocation is controlled in parallel with a predetermined scanning speed in a direction perpendicular to the line scanning direction (main scanning direction) (sub scanning direction).

  The reflection mirror 4 </ b> A extends long along the main scanning direction with a uniform gap with respect to the document placement table 2, and illuminates the document G from the surface facing the document placement table 2.

  The reflection mirror 4B extends long along the reflection mirror 4A and is inclined at a predetermined angle so as to reflect the reflected light image from the original G toward the first mirror 4C.

  The first mirror 4 </ b> C extends long along the reflection mirror 4 </ b> B, and is inclined at a predetermined angle so as to reflect the reflected light image from the document G toward the second scanning unit 5.

  The second scanning unit 5 constitutes a so-called “2/3 mirror”. As shown in FIG. 3, the reflected light from the original G guided by the first mirror 4C of the first scanning unit 4 is used. The second mirror 5A and the third mirror 5B for guiding the image further in a predetermined direction are provided, and the reflected light image from the original G is reflected from the first scanning unit 4 so that the optical lens body 6 is moved. In order to irradiate the CCD 7 and pass through the original G to the CCD 7, the amount of movement is controlled in accordance with the amount of movement of the first scanning unit 4, and the first scanning unit 4 is controlled. The reciprocating movement is controlled in parallel while maintaining a constant speed relationship.

  The optical lens body 6 is disposed on the optical path of the reflected light of the original image guided by the third mirror 5B of the second scanning unit 5, and forms an optical image on a CCD (charge coupled device) 7. It is.

  The CCD 7 reads the optical image of the original image formed by the optical lens body 6 and photoelectrically converts it into an electric signal to create original image information (original image data). The original image information will be described later. It outputs toward the image process part 57 (refer FIG. 7).

  The image processing unit 57 processes the document image information output from the CCD 7 into printing image information (printing image data) whose resolution, density, and the like are suitable for printing. The image information for printing after image processing is transferred to an image data input unit of a laser scanning unit (LSU) 8.

  The laser scanning unit 8 irradiates the surface of the photosensitive drum 11 constituting the image forming unit 10 with laser light corresponding to the printing image information output from the image processing unit 57. Thereby, an electrostatic latent image of image information for printing is written and formed on the photosensitive drum 11.

  On the bottom 3a of the scanner unit 3, as shown in FIG. 5, reflectors 9a for reflecting the irradiation light from the light source that constitutes a part of the document size detecting device 9 are arranged at a plurality of locations corresponding to the document size. ing. In the present embodiment, for example, reflectors 9a1, 9a2, and 9a3 are provided at three locations corresponding to A3 size, A4 size, and B5 size documents.

The reflectors 9a1, 9a2, and 9a3 reflect the irradiation light from the exposure lamp 3A when the exposure lamp 3A is tilted and irradiated toward the bottom 3a of the scanner unit 3 at the time of document size detection, respectively, and are directed upward in the drawing. The reflective surface is provided obliquely so as to irradiate.
In the drawing, the optical path of the irradiation light from the exposure lamp 3A when the document size is detected is indicated by a two-dot chain line.

  As shown in FIG. 6, the document pressing portion (document pressing cover) 51a has separate light receiving sensors 9b1, 9b2, and 9b3 at positions where the reflected light is irradiated corresponding to the reflecting plates 9a1, 9a2, and 9a3, respectively. Is provided. The light receiving sensors 9b1, 9b2, and 9b3 are configured to output detection signals when reflected light from the reflecting plates 9a1, 9a2, and 9a3 is incident, respectively.

  As shown in FIG. 3, the first scanning unit 4 has a bottom 4a closed so that it passes over the reflectors 9a1, 9a2 and 9a3 below the document table 2 when moving when reading the document. It has become. In a state where the first scanning unit 4 is moved and arranged at the image reading position of the original G, the original G is not irradiated with the reflected light from the reflecting plates 9a1, 9a2, 9a3 from below the first scanning unit 4. It has become.

Next, a control system of the image forming apparatus 1 according to the present embodiment will be described.
FIG. 7 is a block diagram illustrating a configuration of an electric control unit of the image forming apparatus according to the present embodiment.
As shown in FIG. 7, the image forming apparatus 1 according to the embodiment includes a program stored in advance in a ROM (Read Only Memory) 55 that performs image reading processing, image processing, image forming processing, paper P conveyance processing, and the like. Accordingly, the central processing unit (CPU) 54 executes processing using temporary storage means such as a RAM (Random access Memory) 56. Note that storage means such as an HDD (hard disk drive) can be used in place of the ROM 55 and the RAM 56.

  In the image forming apparatus 1, document image information (document image data) read by the scanner unit (document reading unit) 3 or document image information transmitted from each terminal device connected to a communication network (not shown) The image data is input to the image processing unit 57 via the processing unit 58.

  The image processing unit 57 processes the document image information stored in the storage unit such as the RAM 56 into a print image suitable for printing (image formation on paper) by the above program.

The image information for printing is input to the image forming unit 10.
Image forming unit 10, paper transport unit (feeding transport path 25, main transport path 16, sub transport path 28 (which are also referred to as paper guides) (various detection / control of paper P) 59, fixing device 30, a paper discharge processing unit (which performs various detection and control of the paper P in the paper discharge conveyance path 17) 60 is linked to each drive control unit 62.

Paper is discharged through a printing process (image information printing process in the image forming unit 10) on the paper P conveyed by the paper conveyance unit 59, and then a fixing process (fixing device 30) for the printed paper P. The sheet is discharged to a sheet discharge tray 22a.
Note that detection signals from the fixing detection switch 21A, the paper discharge detection switch 21B, the pre-registration detection switch 21C, and the like are input to the paper transport unit 59.

  The image forming apparatus 1 is provided with an operating condition setting unit 77. The operation condition setting unit 77 is set by the user using the operation switches 76 and the operation conditions such as image formation or conveyance conditions of the image forming apparatus 1 according to the image formation conditions such as the image formation request or the type of the recording medium. Is set.

  The image forming apparatus 1 is an image reading device that is a driving actuator such as the scanner unit 3, the sheet transport unit 59, the image forming unit 10, the fixing device 30, and the paper discharge processing unit 60 according to the set operating conditions. The drive controller 64, the paper transport drive unit 66, the print processing drive unit 68, the fixing drive unit 70, and the paper discharge drive unit 72 are synchronized with each other in accordance with a command from the CPU 54 based on a program stored in the ROM 55. This is performed under the control of 62.

  The paper discharge processing unit 60 performs control for performing paper discharge processing for discharging the printed paper to the paper discharge tray, and performs paper discharge processing based on a signal output from the paper stacking amount detection sensor 21D. Is.

The image reading drive unit 64 includes driving actuators for the first scanning unit 4 and the second scanning unit 5 of the scanner unit 3.
In the present embodiment, the operation of the image reading drive unit 64 is controlled according to the document size detected by the document size detection device 9.
That is, the document size detection device 9 detects the document size based on the detection signals output from the light receiving sensors 9b1, 9b2, and 9b3, and the image reading drive unit 64 determines the document size based on the document size detection result by the document size detection device. It is controlled to perform an operation according to the above.

The paper transport drive unit 66 is a motor for driving the paper transport unit 59, specifically, the paper pick-up roller 24 and the registration roller 26 on the paper feed transport path 25 described above.
The print processing drive unit 68 is a drive motor for the photosensitive drum 11.
The fixing driving unit 70 is a driving motor for the heating roller 31 and the pressure roller 32 of the fixing device 30.

  The paper discharge drive unit 72 is a drive motor such as the paper discharge drive roller 18 and the paper discharge roller 19. The drive motors of these drive units can be appropriately configured through a power transmission mechanism using the same or different motors as drive sources.

  The image forming apparatus 1 can include an automatic document processing apparatus (document conveying means) 40 as an optional configuration 74, and each of these optional configurations 74 is provided separately from the control unit of the image forming apparatus 1. While having the control part 74a in the structure 74, it is comprised so that timing adjustment with an apparatus may be synchronized via the said communication process part 58. FIG.

  The recording medium detection unit 78 detects that the leading end of the recording medium reaches the fixing device 30 or the carry-out unit. In the present embodiment, the recording medium detection unit 78 detects the timing at which the paper P reaches (enters) the fixing device 30 and the paper discharge drive roller 18 by the conveyance timing detection unit 79b described later. Detection is based on timing.

  Specifically, the recording medium detecting unit 78 includes a conveyance time measuring unit 79a that measures the conveyance time of the paper P after the paper P is sent out from the registration roller 26 that introduces the paper P at the entrance of the paper feeding conveyance path 25. Based on the distance from the registration roller 26 to each of the fixing device 30 to be controlled and the discharge driving roller 18 and the conveyance speed of the paper P, the conveyance timing of the paper P in the main conveyance path 16 and the discharge conveyance path 17 is detected. Conveying timing detecting means 79b.

Next, image reading by the scanner unit 3 according to the present embodiment will be described in detail with reference to the drawings.
FIG. 8 is a block diagram for explaining the control of the scanner unit of the image reading apparatus according to this embodiment.

  In the image reading by the scanner unit 3, as shown in FIG. 8, the original G is irradiated by the exposure lamp 3A, and the reflected light image from the original G is read by the CCD 7 (CCD substrate 7B).

  The light irradiated from the exposure lamp 3A is irradiated toward the original G by the reflecting mirror 4A as shown in FIG. The image light (reflected light image) from the original G irradiated by the reflection mirror 4A is irradiated to the first mirror 4C by the reflection mirror 4B and guided to the second scanning unit 5 by the first mirror 4C. The image light guided to the second scanning unit 5 is irradiated to the CCD 7 through the optical lens body 6 while changing the optical path by the second mirror 5A and the third mirror 5B.

  As shown in FIG. 8, the reflected light image irradiated on the CCD 7 is converted by the CCD 7 and temporarily stored in the ROM 55 and RAM 56 as image data. Then, based on the image data, image processing is performed by the CPU 54 or a program input in advance, and output processing is performed by a writing function 57 a provided in the image processing unit 57.

The drive control of the scanner unit 3 corresponds to the image reading operation by the scanner unit 3 by the optical path length adjustment function (scanner motor drive control) 64a which makes the distance of the optical path of the irradiation light provided in the document reading drive unit 64 constant. Thus, the driving of the first scanning unit 4 and the second scanning unit 5 is controlled.
Thereby, the first scanning unit 4 and the second scanning unit 5 are configured so that the distance of the optical path of the irradiation light from the document G to the CCD 7 is constant, and the first scanning unit and the second scanning unit. 5 is controlled to reciprocate while maintaining a constant speed relationship.

  Note that when the first scanning unit 4 and the second scanning unit 5 are configured to be integrally driven by a wire drive mechanism or the like, drive control by the optical path length adjustment function 64a is unnecessary.

  Next, a document size detection operation by the document size detection device 9 according to the present embodiment will be described with reference to the drawings. Here, as an example, a case where the document size of a B5 size document G placed on the document placement table 2 is detected will be described.

  When the document size is detected by the document size detection device 9, the light emitted from the exposure lamp 3A is applied to the reflectors 9a1, 9a2, and 9a3 disposed on the bottom 3a of the scanner unit 3 as shown in FIGS. In order to irradiate, the lower part 3B1 of the slit part 3B is moved downward in the figure to widen the opening part of the slit part 3B, and the exposure lamp 3A is inclined obliquely downward to reflect the reflecting plates 9a1, 9a2, 9a3. Irradiate toward.

  The reflected light that is irradiated and reflected on the reflectors 9a1, 9a2, and 9a3 is directed upward in the drawing and is irradiated to the light receiving sensors 9b1, 9b2, and 9b3, respectively.

  Since the original G is arranged between the reflecting plates 9a1, 9a2, 9a3 and the light receiving sensors 9b1, 9b2, 9b3, the reflected light from the reflecting plates 9a1, 9a2 reaches the light receiving sensors 9b1, 9b2, respectively. The reflected light from the reflecting plate 9a3 is blocked by the original G.

  At this time, the light receiving sensors 9b1 and 9b2 receive light and are turned on, and the light receiving sensor 9b3 is turned off because it does not receive light. That is, when the light receiving sensors 9b1 and 9b2 are in the ON state and the light receiving sensor 9b3 is in the OFF state, the document G placed on the document placing table 2 is controlled to be B5 by controlling to determine that the document G is B5 size. The size is detected.

  In this way, by specifying the document size according to the light receiving state of the light receiving sensors 9b1, 9b2, and 9b3, the light receiving sensors 9b1, 9b2, and 9b3 due to the reflected light from below the document that varies depending on the document placed on the document placing table 2. The document size can be detected according to the light receiving state.

  Since it is configured as described above, according to the present embodiment, the configuration of the document size detection device 9 is provided with the reflecting plates 9a1, 9a2, 9a3 and the light receiving sensors 9b1, 9b2, 9b3 corresponding to the document size. By using the exposure lamp 3A for irradiating the document as a light source for detecting the document size detected by the sensors 9b1, 9b2, and 9b3, the light source for detecting the document size can be made unnecessary, thereby reducing the number of parts. Space saving of the document size detection device 9 and the scanner unit 3 can be realized.

  In addition, since the light receiving sensors 9b1, 9b2, and 9b3 according to the present embodiment can use general-purpose light receiving sensors, the cost can be reduced, and the apparatus configuration and electrical control can be facilitated.

  Further, according to the present embodiment, by providing the slit portion 3B that can be expanded and contracted in the vicinity of the exposure lamp 3A, the irradiation state by the exposure lamp 3A can be changed during document reading and document size detection. It can be switched easily.

  In the present embodiment, as the configuration of the document size detection device 9, the reflectors 9a1, 9a2, and 9a3 and the light receiving sensors 9b1, 9b2, and 9b3 are provided so as to support three-size documents. Is not limited to the configuration of the reflecting plate and the light receiving sensor, and the number and combination of the reflecting plate and the light receiving sensor can be developed in any manner depending on the size and type of the document to be detected.

  In this embodiment, a fluorescent lamp tube is used as the light source 3A1 of the exposure lamp 3A. However, an LED may be used as the light source.

Hereinafter, a second embodiment in which LEDs are used as light sources of the document size detection device and the scanner unit (image reading device) will be described with reference to the drawings.
(Second Embodiment)
FIG. 9 is an explanatory view showing the configuration of the scanner unit constituting the image reading apparatus according to the second embodiment of the present invention, and FIG. 10 shows the configuration of the reflecting plate constituting the document size detecting device arranged in the scanner unit. It is explanatory drawing shown.

  The image forming apparatus according to the present embodiment has substantially the same configuration and function as the image forming apparatus according to the first embodiment. Accordingly, the same configurations as the basic configurations of the image forming apparatus and the image reading apparatus according to the present embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

  As shown in FIG. 9, the scanner unit 103 mounted in the image forming apparatus according to the present embodiment includes a first scanning unit 4, a second scanning unit 5, an optical lens body 6, and a CCD 7 inside the main body. An original image reading unit 7A and an exposure lamp 103A using LEDs are provided.

  The exposure lamp 103A is configured to irradiate parallel light from the convex optical lens body 103A2 using the LED 103A1 as a light source.

  The exposure lamp 103A is attached so as to be tiltable as in the first embodiment, and its operation is controlled so that the irradiation direction can be changed between when the document size is detected and when the document is irradiated.

On the irradiation light exit side of the exposure lamp 103 </ b> A, a slit portion 3 </ b> B that is long opened along the main scanning direction of the scanner portion 103 is provided. The slit portion 3B is shrunk with a predetermined gap in the height direction with respect to the document placement surface when exposing a normal document, and the height with respect to the document placement surface when detecting the document size. It is configured to expand in the direction (downward in the figure).
In the drawing, the optical path of the irradiation light from the exposure lamp 103A to the original when reading the original image is indicated by a broken line, and the optical path of the image light from the original to the CCD 7 is indicated by an alternate long and short dash line.

  On the bottom 103a of the scanner unit 103, as shown in FIG. 10, a reflecting plate 9a that reflects light emitted from a light source that constitutes a part of the document size detecting device 109 corresponds to the document size, for example, A3 size, Reflecting plates 9a1, 9a2, and 9a3 are provided at three locations corresponding to A4 size and B5 size documents.

The reflectors 9a1, 9a2, and 9a3 reflect the irradiation light from the exposure lamp 103A when the exposure lamp 103A irradiates and tilts toward the bottom 103a of the scanner unit 103 at the time of detecting the document size, and each upwards in the figure. The reflective surface is provided obliquely so as to irradiate.
In the drawing, the optical path of the irradiation light from the exposure lamp 103A when the document size is detected is indicated by a two-dot chain line.

  Similarly to the first embodiment, separate document-type light receiving sensors 9b1 and 9b2 are disposed at positions where reflected light is irradiated to the document pressing portions (document pressing covers) (not shown) corresponding to the reflecting plates 9a1, 9a2 and 9a3, respectively. 9b3. The light receiving sensors 9b1, 9b2, and 9b3 are configured to output detection signals when reflected light from the reflecting plates 9a1, 9a2, and 9a3 is incident, respectively.

  Image reading by the scanner unit 103 and document size detection by the document size detection device 109 according to the present embodiment are performed in the same manner as in the first embodiment.

  Since it is configured as described above, according to the present embodiment, the configuration of the light source can be simplified by adopting the LED as the light source of the document size detection device 109 and the scanner unit 103, and the same as in the first embodiment. An effect can be obtained.

  In addition, this invention is not limited to the structure of the light source of this embodiment mentioned above, You may use the light source by another structure.

Hereinafter, as a modification of the above-described embodiment, an example using a light source having another configuration will be described with reference to the drawings.
FIG. 11 is an explanatory diagram showing an irradiation state along the main scanning direction by another light source according to a modification of the second embodiment, and FIG. 12 is an explanatory diagram showing an irradiation state along the sub scanning direction by the light source.

In this modification, as shown in FIGS. 11 and 12, in the scanner unit 203, as the configuration of the exposure lamp 203A, a plurality of LEDs 203A1 are arranged in parallel along the main scanning direction, and an optical lens body corresponding to each LED 203A1. A lens array 203A2 in which a plurality of 203A21 are arranged in parallel along the main scanning direction is provided.
With this configuration, the same operational effects as those obtained when the exposure lamp 3A of the first embodiment is used can be obtained.

  Note that the present invention is not limited to the image forming apparatus, the image reading apparatus, and the document size detection apparatus described in the above-described embodiments and modifications, and includes a light source that irradiates a document and is irradiated by the light source. As long as the reflected light image of the original is read by a photoelectric conversion element or the size of the original is detected by light detection, the image formation is different from the above-described embodiment or modification. It can also be applied to devices and image readers.

FIG. 1 is a perspective view showing the overall configuration of an image forming apparatus according to an embodiment of the present invention. 2 is a side cross-sectional view illustrating an internal configuration of the image forming apparatus. FIG. FIG. 3 is an explanatory diagram illustrating an example of a configuration of a scanner unit included in an image reading device mounted on the image forming apparatus. It is explanatory drawing which shows the structure of the exposure lamp which comprises the said scanner part. It is explanatory drawing which shows the structure of the reflecting plate which comprises the original document size detection apparatus arrange | positioned at the said scanner part. It is explanatory drawing which shows the positional relationship of the reflecting plate and light reception sensor which comprise the said document size detection apparatus. FIG. 2 is a block diagram illustrating a configuration of an electric control unit of the image forming apparatus. It is a block diagram explaining control of the scanner part of the said image reading apparatus. It is explanatory drawing which shows an example of a structure of the scanner part which comprises the image reader which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows the structure of the reflecting plate which comprises the original document size detection apparatus arrange | positioned at the said scanner part. It is explanatory drawing which shows the irradiation state along the main scanning direction by the other light source of the modification of 2nd Embodiment. It is explanatory drawing which shows the irradiation state along the subscanning direction by the said light source. It is explanatory drawing which shows an example of a structure of the image reading part in the conventional image reading apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 1a Apparatus main body 2 Original mounting stand 3,103,203 Scanner part (image reading means)
3a, 103a Bottom 3A, 103A, 203A Exposure lamp (light source)
3A1 Light source 3A2 Reflector 3B Slit 3B1 Lower side 103A2, 203A21 Optical lens body 4 First scanning unit (moving irradiation means)
4a bottom 4A reflecting mirror 4B reflecting mirror 4C first mirror 5 second scanning unit (light quantity adjusting means)
5A Second mirror 5B Third mirror 6 Optical lens body 7 CCD (photoelectric conversion element)
9,109 Document size detection device 9a1, 9a2, 9a3 Reflector 9b1, 9b2, 9b3 Light receiving sensor (light receiving means)
40A Image Reading Device 57 Image Processing Unit 64 Document Reading Drive Unit 203A1 LED
203A2 Lens array G Original

Claims (9)

A light source for illuminating the original; a moving reflecting means for moving along the sub-scanning direction to irradiate the reading portion of the original with the light source; and condensing image light reflected from the original illuminated by the light source An image reading means having an optical system for reading and a photoelectric conversion element for reading the image light condensed by the optical system, scans a document image line by line, converts it into an electric signal by the photoelectric conversion element, and outputs it A document size detecting device mounted on the image reading device for detecting the size of the document placed on the image reading device,
A reflection plate that reflects the irradiation light from the light source, and a light receiving means that receives the irradiation light from the light source reflected by the reflection plate,
The light source is fixed to the image reading apparatus main body side,
The document size detecting device, wherein the reflection plate is arranged at a plurality of locations corresponding to the document size on the image reading apparatus main body side.   2. The document size detection apparatus according to claim 1, wherein the light source can change an irradiation direction between when the document size is detected and when the document is irradiated. On the irradiation light emission side of the light source, provided with a slit portion opened along the main scanning direction,
3. The document size detection apparatus according to claim 1, wherein the slit portion is provided so as to be able to expand and contract in a height direction with respect to the document placement surface.   The moving reflection means shields the irradiation light from the light source that is reflected by the reflecting plate and irradiated to the document when the irradiation light from the light source is moved to a position to irradiate the document. The document size detection apparatus according to any one of 1 to 3.   5. The document size detection apparatus according to claim 1, wherein the reflection plate is disposed on a side opposite to the document placement side with the moving reflection unit interposed therebetween.   The document size detection apparatus according to claim 1, wherein an LED is used as the light source.   6. The document size detection apparatus according to claim 1, wherein a plurality of LEDs and a lens array are used as the light source. A light source for illuminating the original; a moving reflecting means for moving along the sub-scanning direction to irradiate the reading portion of the original with the light source; and condensing image light reflected from the original illuminated by the light source And an image reading means having a photoelectric conversion element for reading image light condensed by the optical system, and an original size detecting device for detecting the original size, and an original image according to the original size. In the image reading apparatus that scans line by line and converts the electric signal into an electric signal by the photoelectric conversion element, and outputs the electric signal.
An image reading apparatus comprising the image reading apparatus according to claim 1 as the document size detection apparatus. A light source for illuminating the original; a moving reflecting means for moving along the sub-scanning direction to irradiate the reading portion of the original with the light source; and condensing image light reflected from the original illuminated by the light source An image reading unit having an optical system for performing the operation, a photoelectric conversion element for reading the image light condensed by the optical system, and a document size detecting unit for detecting the document size. In an image forming apparatus equipped with an image reading device that scans line by line and converts the electric signal into an electric signal by the photoelectric conversion element and outputs the electric signal,
An image forming apparatus comprising the image reading apparatus according to claim 8 as the image reading apparatus.