JP2010278563A - Image reading device, and image forming apparatus with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To know a floating degree without preparing a new detector, and to cause the draft carrying device not to perform carrying of the draft if the draft carrying device floats so as to cause a jam. <P>SOLUTION: The image reading device is provided with: an image reading unit which prepares a first platen glass through which the draft passes, and a second platen glass on which the draft is placed, and creates image data; and a draft carrying unit which has a detection body which detects placing of the draft, and a mark which faces the first or the second platen glass, prepared upward of the image reading unit, opens in upward and downward directions, and carries the draft to the first platen glass. When reading the draft, the image reading unit performs reading of the mark before start of draft reading, and if the read size of the mark is equal or less than a predetermined size, the draft carrying unit does not perform draft carrying to the first platen glass. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that reads a document such as a scanner. The present invention also relates to an image forming apparatus provided with the image reading apparatus.

  2. Description of the Related Art Conventionally, an image reading apparatus that reads a document and outputs image data is used. The image reading apparatus may be mounted on an image forming apparatus such as a copying machine, a multifunction peripheral, or a FAX apparatus. In addition, the image reading apparatus may be provided with a document conveying apparatus (sometimes referred to as “ADF”) that continuously conveys a plurality of documents toward a reading position. The image reading device continuously reads a continuously conveyed document by an image sensor or the like.

  In general, the document conveying device is provided so as to be openable and closable with respect to the image reading device main body. The document conveying device is lifted, and a document that cannot be conveyed by the document conveying unit such as a book is placed on the platen glass on the upper surface of the image reading device main body. Thus, it is possible to cause the image reading apparatus to read one page at a time. An example of such an image reading apparatus is described in Patent Document 1.

Specifically, Patent Document 1 discloses an image forming apparatus in which an automatic document feeder is mounted on an apparatus main body so that the platen glass can be opened and closed, and a document can be set on the platen glass in a pressure plate mode. An open / close detector that detects the open / close state of the automatic document feeder, a document set detector that detects a document set on the automatic document feeder, and a forgotten document display that indicates that there is a misplaced document on the platen glass If the document set detector detects a set of documents, the document feeding and image forming operations are performed by using the output signal of the open / close detector. And an image forming apparatus provided with a control means for prohibiting the document and displaying the forgotten document indicator. With this configuration, an attempt is made to prevent a document from being damaged due to a jam caused by feeding a document in spite of a miscopy caused by reading a misplaced document or a misplaced document. (See Patent Document 1: Claims, Purpose column, etc.).
JP-A-01-217447

  First, in the image reading apparatus, a platen glass for reading a document conveyed by the document conveying device (hereinafter referred to as “conveying platen glass”) and a document such as a book are placed on the upper surface of the main body and read. Have a platen glass (hereinafter referred to as “mounting platen glass”).

  When transporting a document, the document is transported so as to be in contact with the transport platen glass, and the transport platen glass is used as a part of the transport path. Accordingly, if the lower surface of the document conveying device and the platen glass for conveyance are too far apart, the document cannot be conveyed properly and a jam occurs. For this reason, generally, an open / close detector for checking whether or not the document feeder is closed is provided. As the open / close detector, an optical sensor or a contact sensor that comes into contact with the lower surface of the document conveying device is used. However, since the detection is interlocked with the opening / closing, it is usually provided near the fulcrum of opening / closing of the document conveying device. For this reason, it may be erroneously detected that it is not completely closed but closed. In addition, the image reading device detects that the document transport device has been tilted to some extent with an open / close detector, and triggers the tilt to some extent to read the placement platen glass and confirm the size of the placed document. There is also an image reading apparatus. In such an image reading apparatus, it is determined that the document conveying device is in a closed state even if the document conveying device is not completely closed.

  As described above, since it may be determined that the document conveying device is closed to a certain degree, for example, a thick document such as a book is placed on the placement platen glass, and the document conveying device is Even in a floating state (half-opened state), it may be erroneously detected or determined that the document feeder is closed.

  If the original is placed on the original conveying apparatus in such a state that the original conveying apparatus is floated and the original conveying apparatus is closed, the original conveying apparatus transfers the original. May be done. In this case, since the distance between the transport platen glass and the lower surface of the document transport device is large, there is a problem that the transport cannot be performed accurately, and a jam of the document occurs in the transport platen glass. However, if a detector for accurately measuring whether or not the document conveying device is in a floating state is provided, the manufacturing cost of the image reading device will increase.

  Here, looking at the invention described in Patent Document 1, the output signal of the open / close detector 41 is checked after the copying is completed, and if it is in the open state (H level), it is determined that the document has been removed from the platen glass, and the platen document. The flag is turned OFF, and the copy is not prohibited (Patent Document 1: page 4, left column, lines 32 to 38, see FIG. 8). Accordingly, when the user puts a book or the like, the platen document flag is turned off and the copy prohibition state is not set. As a result, even if the ADF is lifted, if the document is set, the document feeding process is performed. (See Patent Document 1: page 4, right column, lines 14-18). That is, the invention described in Patent Document 1 is for avoiding miscopying due to forgetting a document, and cannot prevent jamming due to document conveyance in a state where the document conveyance device is lifted.

  In view of the above-described problems of the prior art, the present invention grasps the degree of floating of the document conveying device without providing a new detector, and conveys the document if the document conveying device floats enough to cause a jam. It is an object to prevent the document conveying apparatus from performing the above.

  In order to achieve the above object, an image reading apparatus according to a first aspect of the present invention includes a first platen glass that is provided on an upper surface and through which a document passes, and a second platen glass that is provided on the upper surface and on which the document is placed. An image reading unit that emits light toward the upper surface of the first or second platen glass and generates image data by an image sensor based on the reflected light; and a detection body that detects that a document is placed; A mark which is provided on the lower surface and faces the first or second platen glass in a closed state, is provided above the image reading unit, and opens and closes in the vertical direction with respect to the image reading unit by a rotation shaft, A document conveying unit that conveys the document toward the first platen glass, and when reading the document, the image reading unit reads the mark before starting reading the document, and the document conveying unit Is If the size of the mark taken see is less than a predetermined size, even if the document has been placed, it was decided not to perform conveyance of the document to the first platen glass.

  According to this configuration, if the size of the read mark is equal to or smaller than a predetermined size, it can be seen that the mark and the platen glass are largely separated from each other, and the document conveying unit is lifted for placing a book or the like. I understand that Therefore, even if an original is placed on the original conveying portion, the original is not conveyed if the original conveying portion is further away from the platen glass so that the size of the read mark becomes a predetermined size or less. It is possible to prevent a jam from occurring due to the conveyance of the document while the document conveyance unit is floating. The predetermined size is determined on the basis of the size of the mark read when the document transport unit is lifted so that the document jam occurs on the transport platen glass when the document is transported. .

  According to a second aspect of the present invention, in the first aspect of the invention, the image reading unit includes an open / close detector for detecting that the document conveying unit is tilted from a predetermined angle. When the transport unit is tilted below a predetermined angle, a part of the second platen glass is read in order to check the size of the document placed on the second platen glass, and the document transport unit Even if it is detected that the image has fallen by a predetermined angle, if the size of the read mark is equal to or smaller than the predetermined size, the document is not conveyed to the first platen glass.

  According to this configuration, when the document conveying unit is tilted to some extent, it is detected that the document conveying unit is closed, and even if the image reading apparatus reads a part of the second platen glass, the size of the mark is predetermined. If it is smaller than the size, the document is not conveyed. Therefore, it is possible to prevent the jamming of the document due to the document transport while the document transport unit is floating.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the main scanning direction of the image sensor is perpendicular to the axial direction of the rotation shaft, and the document transport unit is the document transport unit. A white guide plate that is a white reference for reading a document extending in the main scanning direction of the image sensor on the lower surface of the image sensor, and that guides the conveyed document. The mark is provided on the white guide plate. .

  According to this configuration, since the reading of the mark and the reading of the white reference in the shading correction can be performed simultaneously, the processing speed before reading can be improved.

  According to a fourth aspect of the present invention, there is provided an image reading apparatus comprising: a first platen glass that is provided on an upper surface and through which a document passes; and a second platen glass that is provided on an upper surface and on which the document is placed. An image reading unit that irradiates light on the upper surface of the second platen glass and generates image data by an image sensor based on the reflected light; a detector that detects that a document is placed; and a lower surface of the document conveying unit A white guide plate that extends in the main scanning direction of the image sensor and serves as a white reference for reading a document and guides the document to be conveyed, and is provided above the image reading unit. A document conveying unit that opens and closes vertically with respect to the image reading unit by a rotation axis whose axis is perpendicular to the main scanning direction, and conveys a document placed on the first platen glass. The original In a state in which the conveyance unit is closed, a white mark is provided on the first platen glass facing the white guide plate, and when reading a document, the image reading unit reads the mark before starting the document reading. When the density around the read mark is higher than a predetermined density, the document transport unit does not transport the document to the first platen glass even if the document is placed. It was decided.

  According to this configuration, the read mark appears clearly, and the darker the density around the mark is, the more the mark is far from the platen glass. I understand that Therefore, even if the document is placed on the document transport unit, if the document transport unit is further away from the platen glass so that the density around the mark is higher than the predetermined density, the document is not transported, and the jam of the document does not occur. Occurrence can be prevented. The predetermined density is determined based on the density around the read mark when the document conveyance unit is lifted so that the document is jammed on the conveyance platen glass when the document is conveyed. It is done.

  According to a fifth aspect of the present invention, in the invention of the fourth aspect, the image reading unit has an open / close detector for detecting that the document conveying unit is tilted by a predetermined angle, and the document conveying unit. When the section is tilted below a predetermined angle, a part of the second platen glass is read in order to check the size of the document placed on the second platen glass. Even if it is detected that the predetermined angle has fallen, if the density around the read mark is higher than the predetermined density, the document is not conveyed to the first platen glass.

  According to this configuration, when the document conveying unit is tilted to some extent, it is detected that the document conveying unit is closed, and even if the image reading apparatus reads a part of the second platen glass, the size of the mark is predetermined. If it is smaller than the size, the document is not conveyed. Therefore, it is possible to prevent the jamming of the document due to the document transport while the document transport unit is floating.

  An image forming apparatus according to a sixth aspect includes the image reading apparatus according to any one of the first to fifth aspects.

  According to this configuration, if a document is set on the document conveyance unit, a thick document such as a book is placed on the second platen glass, and the document conveyance unit is floated so as to cause jamming of the document, document conveyance is performed. Is not done. Accordingly, it is possible to provide an image forming apparatus that does not cause jamming due to document conveyance in a state where the document conveyance unit is floating.

  According to the present invention, when the mark is read by the image reading unit, the document conveying device grasps the degree of floating, and if the document conveying unit is floated so as to cause a jam, the document is not conveyed. Therefore, since no new detector is provided, it is possible to provide an image reading apparatus that does not increase the manufacturing cost and does not cause document jamming due to the floating document transport section.

1 is a schematic cross-sectional view seen from the front showing a schematic configuration of a copier according to a first embodiment. 1 is an enlarged front sectional view of an image reading apparatus according to a first embodiment. 1 is a front view of an example of an image reading apparatus according to a first embodiment. FIG. 3 is a schematic left side cross-sectional view of the image reading apparatus in a state where the document conveying unit according to the first embodiment is opened. 1 is a block diagram illustrating an example of a configuration of a copier according to a first embodiment. 1 is a block diagram illustrating an example of a configuration of an image reading apparatus according to a first embodiment. (A) is a left-side model cross-sectional view showing an example of a closed state of the document conveyance unit according to the first embodiment, and (b) is a left-side model diagram showing an example of a state in which the document conveyance unit is lifted. It is sectional drawing. FIG. 5 is an explanatory diagram illustrating an example of an opening / closing angle of a document conveying unit and reading of a mark according to the first embodiment. 4 is a flowchart showing a flow of control during image reading according to the first embodiment. (A) is a schematic diagram illustrating an example of an image reading unit according to the second embodiment as viewed from above, and (b) is an explanatory diagram illustrating an example of an opening / closing angle of a document conveying unit and reading of a mark. . It is a flowchart which shows the flow of control at the time of the image reading which concerns on 2nd Embodiment.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of image forming apparatus)
First, an outline of an electrophotographic copying machine 200 (corresponding to an image forming apparatus) including the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view from the front showing a schematic configuration of a copying machine 200 according to the first embodiment of the present invention.

  As shown in FIG. 1, a copying machine 200 according to the present embodiment has an image reading apparatus 100 disposed above. The image reading apparatus 100 is mainly provided above the image reading unit 1, and is opened and closed in the vertical direction with respect to the image reading unit 1 by a rotation shaft 2 a, and conveys a document toward the conveying platen glass 11. The image reading unit 1 is arranged below the document conveying unit 2 and irradiates light on the upper surface of the platen glass 12 for conveyance reading or placement, and generates image data by the image sensor 18 based on the reflected light. The Details of the image reading apparatus 100 will be described later.

  Further, as indicated by a broken line in FIG. 1, an operation panel 3 is provided on the front side of the image reading unit 1. The operation panel 3 includes a liquid crystal display unit 30 that displays keys for setting the copying machine 200 and receives user inputs. Further, the liquid crystal display unit 30 can display the status of the copying machine 200 such as an error such as a jam or out of paper. The operation panel 3 is also provided with a numeric keypad 31 for inputting numbers such as the number of copies, a start key 32 for instructing copy execution, and the like.

  Next, the internal configuration and operation of the copying machine 200 will be described. The copying machine 200 includes a paper feeding unit 4a, a conveyance path 4b, an image forming unit 5a, a fixing unit 5b, and the like, and a paper discharge space is provided below the image reading unit 1. Therefore, these configurations will be described along the sheet conveyance path. In FIG. 1, a sheet conveyance path in the copying machine 200 is shown by a solid line arrow.

  First, the paper feed unit 4a is provided at the lowermost part of the copying machine 200, and accommodates various types of paper such as copy paper, OHP paper, label paper, and the like (A4, B5, etc.). The paper feed roller 41 is in contact with the uppermost paper, and is rotationally driven in a predetermined direction (clockwise in FIG. 1) to feed the paper one by one to the transport path 4b.

  In the present embodiment, the conveyance path 4b is a path that conveys a sheet in the copying machine 200 and conveys the sheet from the sheet feeding unit 4a to the discharge tray 42 through the image forming unit 5a. Then, along the conveyance path 4b, a pair of conveyance rollers 43 that are rotationally driven by a drive mechanism (not shown), a plurality of guide plates (not shown) for guiding the paper, and a sheet that matches the formed toner image. A registration roller pair 44 for feeding out the paper, a discharge roller pair 45 for paper discharge, and the like are provided.

  In FIG. 1, the image forming unit 5 a is arranged at the center left position in the copying machine 200, forms a toner image based on image data of a document read by the image reading device 100, and transfers the toner image onto a sheet. . The image forming unit 5a includes a photosensitive drum 51 as an image carrier, a charging device 52, an exposure device 53, a developing device 54, a transfer roller 55, a cleaning device 56, and the like. The photoconductive drum 51 is disposed substantially at the center of the image forming unit 5a, is rotationally driven in a predetermined direction (clockwise in FIG. 1) by a driving device (not shown), and has a photosensitive layer on the outer peripheral surface. The charging device 52 is disposed opposite to the upper right of the photosensitive drum 51 in FIG. 1 and charges the peripheral surface of the photosensitive drum 51 with a predetermined potential. In addition to the corona discharge type, a charging roller, a brush, or the like may be used.

  In FIG. 1, the exposure device 53 is disposed on the right side of the photosensitive drum 51, and irradiates light (for example, laser light) on the peripheral surface of the charged photosensitive drum 51 based on image data of an image to be formed. Then, the peripheral surface is scanned and exposed to form an electrostatic latent image corresponding to the image data. The developing device 54 is provided below the photosensitive drum 51 in FIG. 1, charges the toner to be stored at a predetermined potential, supplies the toner to the electrostatic latent image, and develops the electrostatic latent image as a toner image. .

  In FIG. 1, the transfer roller 55 is rotatably supported diagonally to the left of the photosensitive drum 51 and transfers a toner image formed on the photosensitive drum 51 onto a sheet. For this reason, the transfer roller 55 contacts the photosensitive drum 51 to form a nip. A sheet enters the nip, and a voltage having a polarity opposite to the charging polarity of the toner is applied to the transfer roller 55 to transfer the toner image onto the sheet. In FIG. 1, the cleaning device 56 is disposed above the photosensitive drum 51, and removes and collects residual toner, dust, and the like on the peripheral surface of the photosensitive drum 51.

  In the present embodiment, the fixing unit 5b includes a heating roller 57, a pressure roller 58, and the like, and pressurizes and heats the toner image transferred to the sheet to fix it to the sheet. The heating roller 57 includes a heating element inside, and the pressure roller 58 and the heating roller 57 are pressed against each other to form a nip. A sheet on which the toner image is transferred enters the nip, and the toner is fixed. The sheet after the completion of fixing is discharged to the discharge tray 42 by the discharge roller pair 45.

(Configuration of Image Reading Apparatus 100)
Next, details of the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a front enlarged schematic cross-sectional view of the image reading apparatus 100 portion of the copying machine 200 according to the first embodiment of the present invention. First, the document conveying unit 2 will be described.

  The document transport unit 2 automatically and continuously transports the document to be read one by one to the reading position (a platen glass 11 for transportation described later), and sequentially feeds the document tray 21 and the document supply from the upstream side in the document transport direction. A roller 22, a document transport path 23, a plurality of document transport roller pairs 24, a document discharge roller pair 25, a document discharge tray 26, and the like are provided. The document conveying unit 2 is attached to the image reading unit 1 so as to be able to be opened and closed in the vertical direction with the back side of the sheet of FIG. 2 as a fulcrum, and functions as a cover for pressing each platen glass of the image reading unit 1 from above. The document transport unit 2 is provided with a white guide plate 27 on the lower surface of the document transport unit 2 and facing the transport platen glass 11.

  A plurality of documents are placed on the document tray 21 and connected to the upstream end of the document transport path 23. As shown in FIG. 2, the document tray 21 has a document detection sensor 28 (corresponding to a detector) such as a reflective or transmissive optical sensor that detects that a document is placed on the document tray 21. Is provided. Then, the document supply roller 22 abuts on the uppermost document, and, for example, when an input to read the document is input to the copying machine 200 by pressing the start key 32, the document is sent to the document transport path 23. .

  The fed document is guided to a plurality of document transport roller pairs 24 and guides, and passes through the upper surface of a transport platen glass 11 (corresponding to the first platen glass) provided on the upper surface of the image reading unit 1. During this passage, the image reading unit 1 performs reading. Then, the document that has been read is discharged from the document discharge roller pair 25 to the document discharge tray 26 (the document transport path is shown by a two-dot chain line). Each of the rotating bodies (the document supply roller 22, the document transport roller pair 24, and the document discharge roller pair 25) rotates with a document transport motor 29 (see FIG. 6) as a drive source.

  Next, the image reading unit 1 in the present embodiment will be described. As shown in FIGS. 1 and 2, the image reading unit 1 has a box-shaped housing. Then, on the left side of the upper surface of the image reading unit 1, a transport platen glass 11 having a transparent plate shape is arranged in a direction perpendicular to the paper surface of FIG. Then, a transparent plate-like mounting platen glass 12 (corresponding to a second platen glass) is disposed on the right side of the upper surface of the image reading unit 1 in a direction perpendicular to the paper surface. The placement platen glass 12 is provided on the upper surface of the image reading unit 1, and when reading documents such as books one by one, the document conveying unit 2 is lifted and the document is placed with the reading surface facing downward.

  As shown in FIG. 2, the first moving frame 13, the second moving frame 14, the wire 15W, the take-up drum 15D, the lens 16 and the lamp 170 for irradiating the original with light are provided in the housing of the image reading unit 1. Then, the light irradiated on the original is incident, and an image sensor 18 for reading the original for each line and generating image data is disposed. The image sensor 18 is composed of, for example, a CCD (Charge Coupled Device) in which photoelectric conversion elements are arranged in a line shape, and reads the document line by line based on the reflected light of the document.

  The first moving frame 13 supports a lamp 170 that emits light upward (for example, a cold cathode lamp, a xenon lamp, a fluorescent lamp, etc.) and a first mirror 171 downward. The lamp 170 and each mirror have a shape extending in the direction perpendicular to the paper surface of FIG. The second moving frame 14 supports the second mirror 172 on the upper side and the third mirror 173 on the lower side. The first moving frame 13 is disposed above the second moving frame 14. A plurality of wires 15W are attached to the first moving frame 13 and the second moving frame 14 (only one is shown in FIG. 2 for convenience), and the other end of the wire 15W is connected to the winding drum 15D. The winding drum 15D rotates forward and backward using the winding motor 15M (see FIG. 6) as a drive source, and the first moving frame 13 and the second moving frame 14 can freely move in the horizontal direction.

  Here, an example of a specific document reading operation will be described. First, in the case of reading a document transported by the document transport unit 2, the first moving frame 13 and the second moving frame 14 are driven to the lower position (reading position) of the transport platen glass 11 by driving the winding motor 15M. The lamp 170 irradiates the fixed and passing document.

  The light emitted from the lamp 170 strikes the original on the transport platen glass 11, and the reflected light is reflected by the first mirror 171, the second mirror 172, and the third mirror 173 and guided to the lens 16. The lens 16 condenses the reflected light and enters the image sensor 18. The image sensor 18 converts the reflected light into an analog electric signal corresponding to the image density. By reading the original in units of lines in the main scanning direction (direction perpendicular to the original conveying direction), and repeating the reading in units of lines in the sub-scanning direction (original conveying direction), one original Is read.

  On the other hand, when reading a document placed on the placement platen glass 12, the first moving frame 13 and the second moving frame 14 are moved from the home position to the right in FIG. 2 by the take-up drum 15D or the wire 15W. The entire document is read and the document image is converted into an electrical signal by moving horizontally and sequentially performing the scanning operation up to the document edge.

(Opening / closing of document feeder 2 and opening / closing detection)
Next, based on FIGS. 3 and 4, the opening and closing of the document conveying unit 2 and the opening and closing detection thereof will be described. FIG. 3 is a front view of an example of the image reading apparatus 100 according to the first embodiment of the present invention. In FIG. 3, illustrations other than the image reading apparatus 100 are omitted. FIG. 4 is a schematic cross-sectional view of the left side of the image reading apparatus 100 in a state where the document conveying unit 2 according to the first embodiment of the present invention is opened.

  The document conveying unit 2 is provided on the upper surface of the image reading unit 1 as described above. The document conveying unit 2 is rotatably attached to the support member 2b around two rotation shafts 2a provided on one side of the image reading unit 1 on the back side of the main body. Accordingly, the document conveying unit 2 rotates with the front side of the image reading apparatus 1001 as a free end and swings up and down on the front side, and takes an open and closed posture with respect to the upper surface of the image reading unit 1. be able to.

  A white guide plate 27 is provided on the lower surface of the document transport unit 2 that faces the transport platen glass 11 when the document transport unit 2 is closed. The white guide plate 27 has a position and a size that cover the platen glass 11 for conveyance. When the document transport unit 2 is closed, a gap is formed between the white guide plate 27 and the transport platen glass 11 to provide a path through which the transported document passes. That is, the white guide plate 27 and the conveyance platen glass 11 guide the document.

  A white mat 2 c is provided on the surface facing the platen glass 12 for placing when the document conveying unit 2 is closed. The white mat 2c has a position and size that cover the platen glass 12 for placement. When the document transport unit 2 is closed, the white mat 2c is pressed to hold the document so as not to move.

  Further, in the image reading apparatus 100 of the present embodiment, an area where the image sensor 18 can be read is provided outside the original reading area (see FIG. 10A). On the white guide plate 27, when the document conveying unit 2 is closed, the image sensor 18 can read a region outside the document reading region (the region sandwiched between two two-dot chain lines in FIG. 2). Hereinafter, line-shaped marks M extending in the main scanning direction of the image sensor 18 are provided at positions facing the “mark reading area”). The mark reading areas are provided at two locations on the front side and the back side. Accordingly, each mark is provided on the lower surface of the document conveying unit 2 and is opposed to the conveying platen glass 11 in the closed state, and is provided on each of the front and rear end portions of the white guide plate 27. The lengths of the two marks M are, for example, the same length.

  That is, the main scanning direction of the image sensor 18 is perpendicular to the axial direction of the rotating shaft 2a, and the document conveying unit 2 extends on the lower surface of the document conveying unit 2 in the main scanning direction of the image sensor 18 when reading a document. The white reference plate 27 has a white guide plate 27 for guiding the conveyed document, and the mark M is provided on the white guide plate 27.

  As shown in FIGS. 3 and 4, the image reading unit 1 detects that the document transport unit 2 is tilted by a predetermined angle between the two rotation shafts 2 a of the document transport unit 2. An open / close detector 6 is provided. The open / close detector 6 includes a contact piece 61, a sensor 62, a spring 63, and the like.

  As shown in FIG. 4, the contact piece 61 is a bar-like member extending in the vertical direction, and slides in the vertical direction. The contact piece 61 includes a contact portion 64 whose upper end comes into contact with the lower surface of the document conveying portion 2 when the document conveying portion 2 starts to tilt, and is used for opening / closing detection by the sensor 62 at the lower end. The sensor interference unit 65 is provided.

  The sensor 62 is provided in the vicinity of the sensor interference unit 65 when the document conveying unit 2 is lowered. The sensor 62 is composed of a transmissive optical sensor and includes a light emitting unit and a light receiving unit (not shown). When the document conveying unit 2 is closed to some extent, the sensor interference unit 65 blocks the optical path between the light emitting unit and the light receiving unit of the sensor 62. Thereby, it can be detected that the document conveying section 2 is tilted by a predetermined angle. The spring 63 is provided below the contact piece 61. The spring 63 is constituted by, for example, a compression coil spring, and always urges the contact piece 61 upward. However, the contact piece 61 does not pop out when the document conveying unit 2 is open, and the sensor interference unit 65 is connected to the sensor 62. Energize to the extent that it comes up.

(Hardware configuration of copying machine 200)
Next, an example of the hardware configuration of the copying machine 200 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing an example of the configuration of the copying machine 200 according to the first embodiment of the present invention.

  First, the main body control unit 7 on the main control board of the copier 200 is provided with a CPU 71 as a central processing unit, and includes a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), and the like. The storage unit 72 includes nonvolatile and volatile memories such as a flash ROM. The storage unit 72 stores programs, data, and the like for controlling the copying machine 200. The main body control unit 7 uses the program and data in the storage unit to control each unit and perform printing.

  The main body control unit 7 is connected to the paper feeding unit 4a, the conveyance path 4b, the image forming unit 5a, the fixing unit 5b, and the operation panel 3, and the main body control unit 7 performs various functions such as paper conveyance and toner image formation. Perform motion control. Also, settings and copy execution instructions on the operation panel 3 are transmitted to the main body control unit 7. The main body control unit 7 is also connected to the image reading apparatus 100 and gives an operation instruction to the image reading apparatus 100 at the time of executing a copy (details will be described later). Then, the main body control unit 7 receives image data of the read original at the time of copying, and performs printing (copying) based on the image data.

(Hardware configuration of image reading apparatus 100)
Next, an example of the hardware configuration of the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 6 is a block diagram showing an example of the configuration of the image reading apparatus 100 according to the first embodiment of the present invention.

  As described above, the image reading apparatus 100 according to the present embodiment includes the document transport unit 2 and the image reading unit 1, and the document transport unit 2 includes the document transport control unit 20 that controls the document transport unit 2. The image reading unit 1 is provided with a reading control unit 10 that controls the image reading unit 1.

  The document conveyance control unit 20 will be described. The document conveyance control unit 20 is connected to the main body control unit 7 and the reading control unit 10 described above, receives instructions and signals from the main body control unit 7 and the reading control unit 10, and controls the operation of the document conveyance unit 2. The document conveyance control unit 20 includes a CPU 201 as a central processing unit, a ROM 202, a RAM 203, and the like. The CPU 201 controls communication with the main body control unit 7 and the like, and receives an instruction from the main body control unit 7 and controls the operation of the document conveying unit 2. For example, when a document reading instruction is issued from the main body control unit 7, the document conveying motor 29 is driven to rotate the document supply roller 22, the document conveying roller pair 24, and the like. The ROM 202 and the RAM 203 are memories for storing and developing control programs and data. The document detection sensor 28 is connected to the CPU 201, and the document conveyance control unit 20 detects the presence or absence of documents on the document tray 21 based on the output voltage of the document detection sensor 28.

  Next, schematic configurations of the image reading unit 1 and the reading control unit 10 will be described. As shown in FIG. 6, the reading control unit 10 connected to the main body control unit 7 is provided with a CPU 101, and ROM 102 and RAM 103 are provided as storage devices. The ROM 102 is a non-volatile memory that stores programs and data necessary for controlling the image reading apparatus 100. The RAM 103 is a volatile memory in which programs and data for controlling the image reading apparatus 100 are expanded. The reading control unit 10 can also receive image data from an image memory 84 described later.

  For example, when the start key 32 of the operation panel 3 is pressed and a reading execution instruction is given from the main body control unit 7, the reading control unit 10 receives an instruction from the main body control unit 7, and the operation of the image reading apparatus 100 is performed. Control and transmission control of image data obtained by reading to the main body control unit 7 are performed.

  The following components are connected to the reading control unit 10. For example, an inverter 81 that actually emits light from the lamp 170 of the image reading unit 1, a winding motor 15M for driving the winding drum 15D, an image sensor 18, and the like are connected. Then, when reading, the reading control unit 10 drives the inverter 81, turns on the lamp 170, moves each moving frame with the winding drum 15D, and drives the image sensor 18.

Further, the image reading unit 1 receives an analog electric signal of each pixel obtained by the image sensor 18, converts it into a digital signal, performs quantization, and after A / D conversion A correction unit 83 for performing various corrections on the image data and an image memory 84 for storing the corrected image data are mounted. The correction performed by the correction unit 83 is, for example, non-uniformity of illumination of the lamp 170 in the main scanning direction or a concentration difference depending on the pixel position due to a difference in the degree of light condensing between the central portion and the peripheral portion of the lens 16. There is a shading correction to correct. Specifically, before the image reading, the white guide plate 27 as a white reference is read, and the pixel value of each pixel for one line obtained by the reading is used as a correction coefficient. Thereafter, for each pixel of one line. Make corrections. For example, if each pixel has a density of 256 tones and 255 is white, the following calculation is performed.
Pixel value after correction = Pixel value before correction × (255 / pixel value when reading white guide plate 27)

  The corrected image data is stored in the image memory 84, and the image data in the image memory 84 is transmitted to the main body control unit 7 and further used for exposure by the exposure device 53 after image processing. The image data in the image memory 84 can also be transmitted to the reading control unit 10.

(Original size check operation)
Next, an example of a document size confirmation operation in the image reading apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 7A is a left side schematic cross-sectional view showing an example of the closed state of the document conveying unit 2 according to the first embodiment of the present invention, and FIG. It is a left side model sectional drawing which shows an example.

  FIG. 7A shows that no original is placed on the placement platen glass 12, and even if it is placed, only one to several originals are placed. 2 is a state that can be said to be closed. At this time, as shown in FIG. 7A, the sensor interference unit 65 of the open / close detector 6 blocks the optical path of the sensor 62. Therefore, the voltage input to the reading control unit 10 is that in which the light receiving unit of the sensor 62 is not receiving light (for example, the Low state), and the reading control unit 10 detects that the document conveying unit 2 is closed. To do.

  FIG. 7B shows a state in which a document having a thickness such as a book is placed on the placement platen glass 12, and the document transport unit 2 is in a floating state (half-opened state). In the image reading apparatus 100 according to the present embodiment, the sensor interference unit 65 of the open / close detector 6 blocks the optical path of the sensor 62 even in the floating state shown in FIG. 2 is recognized to be closed. In other words, before the document conveying unit 2 is closed to the lower limit, when the document conveying unit 2 is tilted to a predetermined angle, the sensor interference unit 65 starts to block the optical path of the sensor 62, and the reading control unit 10 Recognized as closed.

  Thus, there is a reason for the reading control unit 10 to recognize that the document transport unit 2 is closed when the document transport unit 2 is tilted to a predetermined angle. In the image reading apparatus 100 of the present embodiment, when the document conveying unit 2 is tilted to a predetermined angle, the image reading unit 1 moves the first moving frame 13 and the second moving frame 14 before actually reading the document. The left end portion of the placement platen glass 12 is read by moving the platen glass 12. By this reading, the size of the placed document can be confirmed. In other words, a preparation operation (pre-scan) for reading a document is performed with the document conveying unit 2 being tilted to a predetermined angle as a trigger. That is, when the document conveying unit 2 is tilted by a predetermined angle, the image reading unit 1 reads a part of the platen glass 12 for placement in order to confirm the size of the document placed on the platen glass 12 for placement.

  Here, the predetermined angle can be set as appropriate. However, even if the lamp 170 is turned on when there is no document on the placement platen glass 12, the user does not feel dazzled by the light of the lamp 170, and the placement platen glass 12 does not feel dazzling. The angle is such that the size of the document placed on the placement platen glass 12 is not erroneously detected (for example, the angle θ formed by the upper surface of the image reading unit 1 and the lower surface of the document conveying unit 2 is about 15 to 30 degrees). When the document conveying unit 2 is tilted to a predetermined angle, the sensor interference unit 65 is adjusted so as to block the optical path of the sensor 62.

  However, as shown in FIG. 7B, when the document conveying unit 2 is in a floating state, it is determined that the document conveying unit 2 is closed only by detection by the open / close detector 6, and it is determined that the document can be conveyed. 7B, as shown in FIG. 7B, the distance between the white guide plate 27 and the transport platen glass 11 is separated, so that the document transport path 23 for transporting the document is interrupted. When the document transport unit 2 transports the document, a jam occurs due to the document that has lost its place of travel.

  Therefore, if it is possible to recognize whether the document conveying unit 2 is in a floating state, or whether the document conveying unit 2 is floating enough to cause a document jam, the jamming due to the floating of the document conveying unit 2 is completely prevented. Can do. In view of this, the image reading apparatus 100 according to the present embodiment does not provide a new sensor 62 or a detector, and the reading of the mark M by the image reading unit 1 allows the document conveying unit 2 and the document conveying unit 2 to be lifted or lifted. Detect.

(Reading of opening / closing angle and mark M)
Next, an example of grasping the opening / closing angle of the document conveying unit 2 and reading the mark M according to the first embodiment of the present invention will be described with reference to FIGS. 3, 7, and 8. FIG. 8 is an explanatory diagram illustrating an example of the opening / closing angle of the document conveying unit 2 and the reading of the mark M according to the first embodiment of the present invention.

  As shown in FIG. 3, a white guide plate 27 that serves as a white reference for shading correction is provided on the lower surface of the document conveying unit 2, and the same shape is provided in a line shape at both ends in the longitudinal direction of the white guide plate 27. A length mark M (for example, black) is marked.

  If the two marks M are read while the document conveying unit 2 is closed, the mark M1 (document conveying unit) positioned on the front side of the image reading apparatus 100 when the document conveying unit 2 is closed. 2 (the free end side) and the size (length) of the mark M2 (the fulcrum side of the document conveying unit 2) located on the back side of the image reading apparatus 100 when the document conveying unit 2 is closed are the same. Become. Whether the mark M1 and the mark M2 are the same size is grasped by checking whether the number of pixels in the main scanning direction of the mark M1 and the mark M2 is substantially the same among the image data obtained by reading the mark M. it can. For example, the reading control unit 10 may obtain image data when each mark M is read from the image memory 84 and count the number of pixels in the main scanning direction. Alternatively, the main body control unit 7 that has received the transmission of the image data when the mark M is read from the image memory 84 may confirm the number of pixels of each mark M in the main scanning direction. In other words, both the reading control unit 10 and the main body control unit 7 can grasp the size of each mark M.

  Then, as shown in FIG. 8, the document conveying unit 2 is brought into a floating state from the closed state, and an inclination angle (in the following description, the inclination angle is the upper surface of the image reading unit 1 in FIG. 7B). And the lower surface of the document conveying unit 2 is inclined), and the lower surface of the document conveying unit 2 is inclined, so that the length of each read mark M is shortened. Further, as shown in FIG. 7B, the distance A from the front mark M1 of the image reading apparatus 100 to the transport platen glass 11 is the distance from the rear mark M2 to the transport platen glass 11. Farther than B. Therefore, the closer the document conveying unit 2 is to the open state (the greater the inclination angle), the smaller the mark M1 is read. As shown in FIG. 8, the mark M <b> 1 is finally not read as the document conveying unit 2 is opened.

  As described above, the number of pixel arrays of the mark M1 in the image data read in advance for each inclination angle of the document conveying unit 2 is acquired and tabulated (for example, stored in the ROM 102), and the mark M1 is read before reading the document. By confirming the size (length), the inclination angle of the document conveying unit 2 can be grasped. Further, since the mark M1 is usually smaller than the mark M2, for example, the size of the mark M1 is compared by comparing the size of the mark M1 and the mark M2 when grasping the inclination angle of the document conveying unit 2. It is also possible to check whether the mark is accurately read by checking whether the mark is smaller.

  Then, the size of the mark M1 is stored as a predetermined size (for example, the number of pixels of the read mark M1) when the original is transported. In other words, a predetermined size of the mark M1 as a floating threshold value of the document transport unit 2 that is unacceptable enough to cause jamming if the document is transported is acquired and stored in advance.

(Control flow during image reading)
Next, an example of a control flow during image reading will be described with reference to FIG. FIG. 9 is a flowchart showing an example of a control flow at the time of image reading according to the first embodiment of the present invention.

  First, the start in FIG. 9 is the time when the start key 32 on the operation panel 3 is pressed and the copy operation is started. If the original is placed on the placement platen glass 12 before the start key 32 is pressed, pre-scanning has already been performed, the size of the placed original is confirmed, and the paper feed unit 4a. In this state, confirmation is made as to whether or not the size of the paper stored in the container matches the size.

  Next, the reading control unit 10 of the image reading unit 1 positions the first moving frame 13 and the second moving frame 14 below the platen glass 11 for conveyance, emits light from the lamp 170, and performs white guide for shading correction. The board 27 is read to obtain a white reference (step # 1). Next, the first moving frame 13 and the second moving frame 14 are moved from the white reference acquisition position, and the marks M1 and M2 are read (step # 2).

  Next, the document conveyance control unit 20 confirms the output of the document detection sensor 28 and confirms whether a document is placed on the document tray 21 of the document conveyance unit 2 (whether there is a document) (step # 3). If there is a document on the document tray 21 (Yes in step # 3), the reading control unit 10 confirms the output of the open / close detector 6, and the document conveying unit 2 is tilted so that the upper surface of the image reading unit 1 and the document are scanned. It is confirmed whether the angle formed by the lower surface of the transport unit 2 is equal to or smaller than a predetermined angle and the closed state is recognized by the open / close detector 6 (step # 4).

  If the closed state is detected (Yes in step # 4), the reading control unit 10 confirms the image data of each mark M read first, and the front side mark M1 is the rear side mark M2. (Step # 5). That is, it is confirmed whether the front side mark M1 ≦ the back side mark M2. If the mark M on the front side is larger (No in Step # 5), a reading error is considered, and for the sake of accuracy, for example, the process returns to Step # 2.

  On the other hand, if the front-side mark M1 is not larger (Yes in Step # 5), it is confirmed whether the front-side mark M1 of the copying machine 200 is equal to or smaller than a predetermined size (Step # 6). At this time, the mark M1 on the front side of the copying machine 200 (the free end side of the document conveying unit 2) and the mark M2 on the back side of the copying machine 200 (the fulcrum side of the document conveying unit 2) are compared, and the front of the copying machine 200 is compared. It may be determined whether the mark M1 on the side is smaller than a certain size, whether or not it is smaller than a predetermined size.

  If the mark M1 is not smaller than the predetermined size (No in Step # 6), the document transport unit 2 is not in a floating state to the extent that a jam occurs in the transport platen glass 11 even when the document is transported. Since the determination can be made, the reading control unit 10 instructs the document conveyance control unit 20 to convey the document, and the document conveyance control unit 20 continuously conveys the document (step # 7). Thereafter, the reading control unit 10 moves the first moving frame 13 and the second moving frame 14 to the reading position of the conveyed document (below the conveying platen glass 11), and the image sensor 18 continuously moves the document. Reading is performed (step # 8). After reading by the image sensor 18, image data is generated and transmitted to the main body control unit 7 (step # 9). Then, printing is performed (step # 10), and the copying operation is completed (end).

  On the other hand, there is no document on the document tray 21 of the document transport unit 2 (No in step # 3), and even if a document is placed on the document transport unit 2, the document transport unit 2 is not tilted to a predetermined angle. If the open state is detected by the open / close detector 6 (No in Step # 4), or if the mark M1 is equal to or smaller than the predetermined size (Yes in Step # 6), the document transport unit 2 transports the document. Instead, the reading control unit 10 horizontally moves the first moving frame 13 and the second moving frame 14 below the placing platen glass 12 to read the original on the placing platen glass 12 ( Step # 11). Then, after step # 11, the process proceeds to step # 9, where image data is transmitted and printed, and the process ends (END).

  That is, when reading a document, the image reading unit 1 reads the mark M1 and the mark M2 before starting to read the document, and the document conveying unit 2 sets the size of the read mark M1 to a predetermined size. In the following cases, even when a document is placed, the document is not transported to the transport platen glass 11. Further, even if it is detected that the document conveying unit 2 has fallen by a predetermined angle, the document conveying unit 2 applies the reading to the conveying platen glass 11 when the size of the read mark M1 is equal to or smaller than the predetermined size. Do not transport the document.

  In this way, if the size of the read mark M1 is equal to or smaller than a predetermined size, it can be seen that the mark M1 and each platen glass are greatly separated from each other. It can be seen that 2 is floating. Therefore, even if a document is placed on the document transport unit 2, if the document transport unit 2 is further away from the platen glass as the size of the read mark M becomes smaller than a predetermined size, the transport of the document can be performed. It is not performed, and jamming due to the conveyance of the document while the document conveyance unit 2 is floating can be prevented.

  Further, when the document conveying unit 2 is tilted to some extent, the open / close detector 6 detects that the document conveying unit 2 is closed, and even in the image reading apparatus 100 that reads a part of the second platen glass, the mark M1 When the size is equal to or smaller than the predetermined size, the document is not conveyed. Accordingly, it is possible to prevent the jamming of the document due to the document transport while the document transport unit 2 is floating. Further, since reading of the marks M1 and M2 and reading of the white reference in the shading correction can be performed at the same time, the processing speed before reading can be improved.

(Second Embodiment)
Next, a second embodiment will be described based on FIGS. 10 and 11. The second embodiment is different in that the mark M is provided on the image reading unit 1 side instead of the white guide plate 27, but the configurations of the copying machine 200, the image reading unit 1, the document conveying unit 2, and the like are the same. Well, the description of common parts is omitted, and the same reference numerals are used.

  FIG. 10A is a schematic diagram showing an example of the image reading unit 1 according to the second embodiment of the present invention as viewed from above, and FIG. 6 is an explanatory diagram illustrating an example of reading a mark M. FIG. FIG. 11 is a flowchart showing an example of the flow of control during image reading according to the second embodiment of the present invention. In FIG. 10, description of the document conveyance unit 2, the open / close detector 6, the rotating shaft 2 a, and the like is omitted, and only each platen glass and each mark M is shown.

  As described above, on the upper surface of the image reading unit 1, the transport platen glass 11 is provided on the left side when viewed from the front, and the placement platen glass 12 is provided on the right side. As shown in FIG. 10A, even in the image reading apparatus 100 of the present embodiment, two two-dot chain lines in the reading area of the document that passes through or is placed on the document (FIG. 10A). The image sensor 18 can be read by two areas (hereinafter referred to as “mark reading areas”) on the front side and the back side. In other words, the mark reading area is set with a constant width from the front and back edges of the transport platen glass 11 and the placement platen glass 12.

  In the image reading apparatus 100 according to the present embodiment, as shown in FIG. 10A, a white mark M3 that is the same as the white guide plate 27 in a line shape, for example, is provided on the front side of the transport platen glass 11. The same white mark M4 as the white guide plate 27 is provided in a line shape in both mark reading areas on the back side. That is, the white mark M is provided on the transport platen glass 11 facing the white guide plate 27 in a state where the document transport unit 2 is closed. Further, the mark M3 and the mark M4 may be attached to the upper surface of the transport platen glass 11, or may be drawn with a paint or the like. The size (length) of the two marks M3 and M4 is, for example, the same length.

  Further, as shown in FIG. 10B, when the two marks M are read when the document conveying section 2 is closed (inclination angle 0 degree), the marks M3 and M4 are positioned above. Even if the mark M3 and the mark M4 are read, the white image is recognized as a white image.

  Then, as shown in FIG. 10B, the distance between the platen glass 12 for placement and the white guide plate 27 increases as the document conveying unit 2 is closed to the floating state and the inclination angle increases. Thus, the reflected light from the lamp 170 is difficult to be guided into the image reading unit 1, and when the image data obtained by reading the mark M is confirmed, the mark M3 and the mark M4 emerge. In other words, the density (pixel value) around the white marks M3 and M4 is higher than when the document conveying unit 2 is closed.

  Further, when the document conveying section 2 is opened, the distance from the front-side mark M3 to the conveying platen glass 11 becomes longer than the distance from the rear-side mark M4 to the conveying platen glass 11. Accordingly, the density of the pixels around the mark M3 increases as the inclination angle of the document conveying unit 2 increases. For example, as shown in FIG. 10B, as the inclination angle of the document conveying unit 2 increases, the mark M3 finally comes to the full surface.

  Accordingly, if the density (pixel value) of pixels around the mark M3 (front side, the free end side of the document transport unit 2) and the mark M4 (back side, fulcrum side of the document transport unit 2) is confirmed, the document transport is performed. The inclination angle of the part 2 can be grasped. For example, the mark M3 is read in advance for each inclination angle of the document conveying unit 2 to obtain the density (pixel value) around the mark M3 in the image data, and is tabulated (for example, stored in the ROM 102) before reading the document. In addition, by confirming the density of the pixels around the mark M3, the inclination angle of the document conveying section 2 can be grasped. Further, since the density of the pixels around the mark M4 is usually lower, for example, when the inclination angle of the document conveying unit 2 is grasped, the density of the pixels around the mark M3 and the mark M4 is compared. Thus, it may be confirmed whether the pixel around the mark M4 has a lower density and whether the mark M has been read accurately.

  Next, an example of a control flow at the time of image reading according to the second embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart showing an example of the flow of control during image reading according to the second embodiment of the present invention.

  First, steps from start to step # 24 in this flowchart are the same as start to step # 4 in FIG.

  If the closed state is detected (Yes in step # 24), the reading control unit 10 confirms the image data of each mark M read first, and the density around the mark M3 on the front side is higher. Then, it is confirmed whether it is thinner than the mark M4 on the back side (step # 25). If the density of the pixels around the mark M3 on the front side is lighter (No in Step # 25), a reading error is considered, and for accuracy, for example, the process returns to Step # 22.

  If the density around the mark M3 on the front side is not lighter than the mark M4 on the back side (Yes in step # 25), the reading control unit 10 confirms the image data of the mark M3 read first and copies it. It is confirmed whether the density around the mark M3 on the front side of the machine 200 is higher than a predetermined density (step # 26). If the density around the mark M3 is lower than the predetermined density (No in step # 26), the original transport unit 2 becomes more jammed as the jam occurs in the transport platen glass 11 even if the original is transported. Since it can be determined that it is not floating, the reading control unit 10 gives an instruction to the document conveyance control unit 20 to convey the document, and the document conveyance control unit 20 continuously conveys the document (step # 27). ). On the other hand, if the density is higher than the predetermined density (Yes in step # 26), the process proceeds to step # 31. Note that steps # 27 to # 31 in the present embodiment are the same as steps # 7 to # 11 in FIG. 9 in the first embodiment, and a description thereof will be omitted.

  As described above, in the second embodiment, when reading an original, the image reading unit 1 reads the marks M3 and M4 before starting the reading of the original, and the original conveying unit 2 reads the read mark. When the density around M3 is higher than the predetermined density, the document is not transported to the transport platen glass 11 even if the document is placed. Further, even if it is detected that the document conveying unit 2 is tilted by a predetermined angle, the document conveying unit 2 applies the platen glass 11 for conveyance when the density around the read mark M3 is higher than the predetermined concentration. Do not transport the document.

  Thus, according to the configuration of the present embodiment, the read mark M3 appears more clearly, and the darker the density around the mark M3 is, the farther the mark M3 is from the platen glass. It can be seen that the document conveying section 2 is floating, for example. Therefore, even if a document is placed on the document transport unit, if the document transport unit 2 is further away from the platen glass as the density around the mark M3 is higher than the predetermined density, the document is not transported and the document is not transported. Jam can be prevented from occurring. Further, when the document conveying unit 2 is tilted to some extent, it is detected that the document conveying unit 2 is closed, and even in the image reading apparatus 100 that reads a part of the second platen glass, the size of the mark M is predetermined. If it is smaller than the size, the document is not conveyed. Accordingly, it is possible to prevent the jamming of the document due to the document transport while the document transport unit 2 is floating.

  Next, another embodiment will be described. In the above description, the line-shaped mark M has been described as an example of the mark M. However, for example, a circle, an ellipse, a polygon, a character, or the like may be readable, and is not limited to a line. Further, when using a mark other than a line, in the first embodiment, for example, it may be determined whether or not it is a predetermined size or less based on the number of pixels of each mark M portion in the read image data.

  Further, in the first embodiment, the example in which the mark M is provided at the end portion in the longitudinal direction of the white guide plate 27 has been described. It may be provided at a place. Further, the mark M may be provided on the white mat 2c.

  In the second embodiment, the white mark M is provided in the mark reading area of the transport platen glass 11. However, the white mark M is provided in the mark reading area of the mounting platen glass 12. May be.

  The first embodiment of the present invention has been described above, but the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used for an image reading apparatus and an image forming apparatus including the image reading apparatus.

DESCRIPTION OF SYMBOLS 1 Image reading part 11 Platen glass for conveyance (1st platen glass)
12 Platen glass for mounting (second platen glass)
DESCRIPTION OF SYMBOLS 18 Image sensor 2 Original conveyance part 2a Rotating shaft 27 White guide plate 28 Original detection sensor (detection body) 6 Opening / closing detector 100 Image reading apparatus 200 Copying machine (image forming apparatus)
M, M1, M2, M3, M4 mark

Claims (6)

A first platen glass that is provided on the upper surface and through which a document passes; and a second platen glass that is provided on the upper surface and on which the document is placed; and irradiates light toward the upper surface of the first or second platen glass; An image reading unit for generating image data by an image sensor based on the reflected light;
A detector for detecting that a document is placed; a mark provided on a lower surface and facing the first or second platen glass in a closed state; provided above the image reading unit; A document conveying unit that opens and closes in a vertical direction with respect to the image reading unit by a rotation shaft, and conveys a document toward the first platen glass,
When scanning a document,
The image reading unit reads the mark before starting to read the document,
The document transport unit does not transport the document to the first platen glass even when the document is placed when the size of the read mark is equal to or smaller than a predetermined size. An image reading apparatus. The image reading unit includes an open / close detector for detecting that the document conveying unit is tilted from a predetermined angle. When the document transport unit is tilted by a predetermined angle, the image reading unit is attached to the second platen glass. In order to confirm the size of the placed document, a part of the second platen glass is read,
Even if it is detected that the document conveying unit has fallen by a predetermined angle, the document conveying unit detects the document on the first platen glass when the size of the read mark is not more than a predetermined size. The image reading apparatus according to claim 1, wherein no conveyance is performed. The main scanning direction of the image sensor is perpendicular to the axial direction of the rotation axis,
The document transport unit has a white guide plate on the lower surface of the document transport unit that extends in the main scanning direction of the image sensor and serves as a white reference when reading a document, and guides the document to be transported.
The image reading apparatus according to claim 1, wherein the mark is provided on the white guide plate. A first platen glass that is provided on the upper surface and through which a document passes; and a second platen glass that is provided on the upper surface and on which the document is placed; and irradiates light toward the upper surface of the first or second platen glass; An image reading unit for generating image data by an image sensor based on the reflected light;
A detector for detecting that a document is placed, and a white guide that extends in the main scanning direction of the image sensor on the lower surface of the document transport unit and serves as a white reference for document scanning and guides the document to be transported And is opened and closed in the vertical direction with respect to the image reading unit by a rotation shaft having an axis direction perpendicular to the main scanning direction of the image sensor. A document conveying section that conveys a document placed on one platen glass,
In a state where the document conveying unit is closed, a white mark is provided on the first platen glass facing the white guide plate,
When scanning a document,
The image reading unit reads the mark before starting to read the document,
The document transport unit does not transport the document to the first platen glass even when the document is placed when the density around the read mark is higher than a predetermined density. An image reading apparatus. The image reading unit includes an open / close detector for detecting that the document conveying unit is tilted from a predetermined angle. When the document transport unit is tilted by a predetermined angle, the image reading unit is attached to the second platen glass. In order to confirm the size of the placed document, a part of the second platen glass is read,
Even if it is detected that the document conveying unit has fallen by a predetermined angle, the document conveying unit detects the document on the first platen glass when the density around the read mark is higher than the predetermined density. The image reading apparatus according to claim 4, wherein no conveyance is performed.   An image forming apparatus including the image reading apparatus according to claim 1.

Images