JP2017073627A - Image reading device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reading device that can make a user aware of abnormality of an optical sensor for detecting the size of a sheet placed on a tray.SOLUTION: An image reading device comprises: a document presence/absence detection sensor 10 that detects the presence or absence of a sheet on a tray; and a document length sensor 15 that is provided on the upstream side in a sheet conveyance direction with respect to the document presence/absence detection sensor 10 for detecting the length in the conveyance direction of the sheet placed on the tray. After the sheet placed on the tray is conveyed to read an image of the sheet, when the document presence/absence detection sensor 10 outputs a signal about the absence of a document and the document length sensor 15 outputs a signal about the presence of a document, the image reading device notifies a user of abnormality of the document length sensor 15.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image reading apparatus that feeds originals placed on a tray one by one and reads an image of the original conveyed at a reading position, and an image forming apparatus including the image reading apparatus.

  An image reading apparatus such as a copying machine is equipped with a so-called automatic document feeder (hereinafter referred to as “ADF”) that can continuously convey originals to be read one by one. Are known. In this image reading apparatus, a scanning operation is generally performed in which originals are continuously conveyed by ADF one by one, and images are optically read from these originals to obtain image data.

  When a document conveyed by the ADF is read, the size of the document may be detected on a tray on which a document bundle made up of a plurality of documents is placed, and an image area of the detected size may be read. Using the document size detected on the tray, it is possible to proceed with processing such as determining the paper feed stage of the printer in which the corresponding recording paper is stored, thereby improving productivity and FCOT (First Copy Output Time). it can.

  However, the document may be bent or curled (curved) on the tray on which the document bundle is placed. In this case, the size of the document may not be detected correctly on the tray. For example, when a Z-folded A3-sized document P is placed on the document tray 30 in a folded state as shown in FIG. 11, the document length sensor 15 may erroneously detect it as an A4 size. . In this case, when the image area of the detected original size is read, the image may be lost, and the original may be jammed.

  In order to reduce the possibility of the occurrence of the above phenomenon, the size of the document P at a position floating from the document tray 30 is detected by using an optical sensor for the document length sensor 15 on the document tray 30. Technology has been proposed (Patent Document 1).

JP 2004-347926 A

  However, when an optical sensor is used as the document length sensor on the document tray 30 as in Patent Document 1, if paper dust or dust accumulates on the optical sensor, the size of the document on the document tray 30 will be described. May not be detected correctly.

  When paper dust or dust is not accumulated in the document length sensor 15 which is an optical sensor, the light emitted from the light emitting unit 17 is reflected by the document P and received by the light receiving unit 18 as shown in FIG. The presence or absence of a document is detected.

  On the other hand, as shown in FIG. 13, when paper dust, dust, or the like is accumulated on the document length sensor 15, the light from the light emitting unit 17 is blocked by the paper dust and the light receiving unit 18 cannot receive light. Therefore, regardless of the presence or absence of the document P, the document length sensor 15 remains off (the document length sensor 15 always outputs a signal indicating that there is no document P). If an A4R (paper width 210 mm) size document is placed on the tray 30 in this state, the document length sensor 15 remains off, and the document is an A5 (solid line size in FIG. 14) size document having the same width as the A4R size. There is a possibility of false detection. Similarly, there is a possibility that a document having an LTRR (paper width of 215.9 mm) size is erroneously detected as an STMT size document having the same width as the LTRR size.

  Further, as shown in FIG. 15, when paper dust, dust, or the like is accumulated on the document length sensor 15, regardless of the presence or absence of the document P, the paper dust or the like accumulated on the document length sensor 15 The light will always be reflected. As a result, the light receiving unit 18 receives reflected light from paper dust or the like, so that the document length sensor 15 remains on regardless of the presence or absence of the document (a signal indicating that the document length sensor 15 always has the document P). Output state). If an STMT (paper width 215.9 mm) size original is placed on the tray 30 in this state, the original length sensor 15 remains ON, so an LTRR (solid line size in FIG. 16) size original having the same width as the STMT size is used. There is a possibility of false detection. Similarly, an A5 (paper width 210 mm) size document may be erroneously detected as an A4R size document having the same width as the A5 size.

  As described above, if the size of the original to be read is erroneously detected as described above, the read image may be lost or the original may be jammed. Therefore, for example, when the image reading apparatus determines that an A3 size document is Z-folded and has been erroneously detected as an A4 size document, an operation display unit of the image reading apparatus as shown in FIG. A message is output. Since the document is not Z-fold paper, the user presses a cancel button for canceling the job for reading the image of the document. As a result, the job cannot be flowed, and downtime of the apparatus occurs. On the other hand, since the user cannot notice that the document length sensor 15 is operating abnormally, reading by the image reading apparatus cannot be performed.

  Accordingly, an object of the present invention is to provide an image reading apparatus that allows a user to notice an abnormality of an optical sensor for detecting the size of a sheet placed on a tray.

  In order to achieve the above object, according to the present invention, an image reading device feeds a sheet placed on a tray and reads an image of a conveyed sheet at a reading position. A sheet presence / absence detection sensor that detects the presence / absence of a sheet, and an optical type that is provided upstream of the sheet presence / absence detection sensor in the sheet conveyance direction and detects the length in the conveyance direction of the sheet placed on the tray The first sheet length detection sensor, and the sheet presence / absence detection sensor outputs a signal related to the absence of the sheet after the conveyance of the sheet to read the image of the sheets stacked on the tray, and the first sheet length detection And a control unit that performs control for notifying abnormality of the first sheet length detection sensor when the sensor outputs a signal related to the presence of a sheet.

  According to the present invention, in an image reading apparatus that feeds a sheet placed on a tray and reads an image of the conveyed sheet at a reading position, the length of the sheet placed on the tray in the transport direction. An optical first sheet length detection sensor for detecting the sheet length, and a first sheet length detection sensor upstream of the first sheet length detection sensor for detecting the length in the conveyance direction of the sheet placed on the tray. The second sheet length detection sensor and the first sheet length detection sensor output a signal related to the absence of a sheet, and the image is read in a state where the second sheet length detection sensor outputs a signal related to the presence of a sheet. A control unit that performs control for notifying abnormality of the first sheet length detection sensor.

  According to the present invention, it is possible to provide an image reading apparatus that allows a user to notice an abnormality of an optical sensor for detecting the size of a sheet placed on a tray.

Cross section of image reader Block diagram of image reader View of image reader from above Flowchart for detecting an abnormality in the document length sensor on the document tray Flowchart for detecting an abnormality in the document length sensor on the document tray Table to judge the document size from the detection result of the detection sensor Illustration of abnormal condition of document length sensor Illustration of abnormal condition of document length sensor Illustration of abnormal condition of document length sensor Display screen at cleaning alarm Cross section of a folded document Cross section of optical document length sensor Sectional view when paper dust adheres to the optical document length sensor Illustration of false detection when document length sensor is abnormal Sectional view when paper dust adheres to the optical document length sensor Illustration of false detection when document length sensor is abnormal Display screen when the size of the document on the document tray is different from the actual size of the document

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

  Hereinafter, a configuration example of an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an example of an image forming apparatus including the image reading apparatus according to the present exemplary embodiment. The image forming apparatus 500 according to the present exemplary embodiment includes an image forming apparatus main body 400 (image forming unit) and an image reading apparatus 1000. The image reading apparatus 1000 includes an image reading unit 200 that reads an image on a sheet (hereinafter referred to as a document) and an automatic document feeding / conveying device unit (hereinafter referred to as an ADF) 100. Further, FIG. ) Is connected. The image forming apparatus main body 400 forms an image by a known electrophotographic method. The image forming apparatus main body 400 includes a photoconductor, an exposure device, a developing device, a transfer device, and a fixing device as an image forming unit. The exposure apparatus forms an electrostatic latent image on the photoconductor based on the image information acquired by the image reading apparatus 1000. The developing device develops the electrostatic latent image into a developer image with toner. The transfer device transfers the developer image to the recording medium that has been conveyed. The fixing device fixes the developer image on the recording medium to the recording medium.

<Configuration Example of Image Reading Unit 200>
The image reading unit 200 will be described with reference to FIG. As shown in FIG. 1, the image reading unit 200 scans a document placed on a document tray glass 209 by scanning the optical scanner unit 202 at a constant speed in the sub-scanning direction indicated by the arrow in FIG. The recorded image information is read line by line (fixed reading). For the document on the ADF 100, the optical scanner unit 202 is moved so as to come to the center position (reading position) of the read roller 7 of the ADF 100, and the document fed and conveyed one by one by the method described later is read position. Read optically (flow-reading).

<Configuration Example of Automatic Document Feeder (ADF) 100>
The operation of the ADF 100 will be described with reference to FIG. As shown in FIG. 1, the ADF 100 includes a document tray 30 on which a document bundle S composed of one or more documents is stacked, and the document bundle S protrudes from the document tray 30 to the downstream side before the document conveyance starts. A separation upper roller 2 and a separation lower roller 3 that restrict the advancement, and a paper feed roller 1 are provided. The document tray 30 has a document presence / absence detection sensor 10 so that the presence / absence of a document on the document tray 30 can be detected. The paper feed roller 1 rotates by dropping on the original surface of the original bundle S stacked on the original tray 30. As a result, the uppermost document of the document bundle S is fed. The uppermost sheet of the original fed by the paper feed roller 1 is separated and conveyed by the action of the separation upper roller 2 and the separation lower roller 3. This separation is realized by a known separation technique.

  The document separated by the separation upper roller 2 and the separation lower roller 3 is conveyed to the registration roller 5 by the drawing roller 4 and is abutted against the registration roller 5. As a result, a loop-like deflection is formed on the original, and the skew in the conveyance of the original is eliminated. On the downstream side of the registration roller 5, a paper feed path is provided for feeding the original that has passed through the registration roller 5 to the surface of the reading glass 201.

  The document sent to the paper feed path by the registration roller 5 is conveyed to the image reading position by the reading upstream roller 6. When passing between the flow-reading glass 201 and the read roller 7, the surface of the original is irradiated by the LEDs 203a and 203b. The reflected light is bent by the plurality of mirrors 204a, 204b, and 204c, and the image reading sensor 208 reads the surface image of the document line by line. Thereafter, the document is conveyed by the reading downstream roller 8. The original conveyed by the reading downstream roller 8 is conveyed to the paper discharge tray 31 by the paper discharge roller 9 while passing through the paper discharge sensor 13 when only the surface image of the original is read.

  When reading the back side image of the original, the front side image is read, and after the rear end of the original passes through the paper discharge sensor 13, the original is stopped before passing through the paper discharge roller 9. Then, by rotating the paper discharge roller 9 in the reverse direction, the original is conveyed toward the registration roller 5, and the reverse side of the original can be read by conveying the original in the same manner as described above.

  Further, after the reading of the back image is completed, after the trailing edge of the document has passed through the paper discharge sensor 13, the document is stopped before passing through the paper discharge roller 9, and the document is conveyed again toward the registration roller 5 to obtain the image. The paper is conveyed to the paper discharge tray 31 without being read. As a result, after all the original images are read, the arrangement order of the originals on the original tray 30 before the image reading is the same as the original arrangement order of the originals discharged to the paper discharge tray 31.

<Explanation of block diagram>
FIG. 2 is a block diagram illustrating a configuration example of a control unit of the image reading apparatus according to the present exemplary embodiment including an ADF. The document reading / ADF controller 310 (control unit) includes a central processing unit CPU (A) 801, a read only memory ROM (A) 802, and a random access memory RAM (A) 803 (storage unit). It has. The ROM (A) 802 stores a control program, and the RAM (A) 803 stores input data and work data. The CPU (A) 801 as the control unit executes the control program according to the flow shown in FIGS.

  The CPU (A) 801 is connected to a separation motor 805 that rotationally drives the paper feed roller 1, the separation upper roller 2, the drawing roller 4, and the registration roller 5 in order to realize a document conveying function. The CPU (A) 801 is connected to a reading motor 806 for driving the reading upstream roller 6, the reading roller 7, the reading downstream roller 8, and the paper discharge roller 9 in order to realize a document conveying function.

  The CPU (A) 801 is connected to an optical motor 804 for moving the optical scanner unit 202 that reads the image information recorded on the document.

  Further, the CPU (A) 801 is connected to a document presence / absence detection sensor 10 (sheet presence / absence detection sensor) that detects the presence / absence of a document loaded on the document tray 30. The CPU (A) 801 is connected to document length sensors 15 and 16 for detecting the length of the document placed on the document tray 30 in the conveyance direction. The CPU (A) 801 is connected to a registration sensor (sheet detection sensor) 11, a lead sensor 12, and a paper discharge sensor 13 that are provided in a conveyance path for guiding a document to be conveyed and detect an edge of the document. The CPU (A) 801 is connected to a document width sensor (sheet width detection sensor) 14 that detects the length in the width direction orthogonal to the document transport direction (hereinafter also referred to as document width).

  The optical motor 804, the separation motor 805, and the reading motor 806 are pulse motors, and the CPU (A) 801 manages the rotation speed of each motor by performing control while counting the number of drive pulses. The CPU (A) 801 can detect the length in the conveyance direction of the document being conveyed by counting the number of drive pulses of the separation motor 805 from when the registration sensor 11 is turned on to when it is turned off during document conveyance. it can.

  Even in a state where a document is placed on the document tray 30, the document length sensors 15 and 16 can be used to determine the length of the document in the conveyance direction. The document length sensor 15 (first sheet length detection sensor) is provided upstream of the document presence / absence detection sensor 10 in the document transport direction, and the document length sensor (second sheet length detection sensor) 16 transports the document from the document length sensor 15. It is provided upstream in the direction. For example, the distance from the document leading edge position O to the document length sensor 15 with the document placed on the document tray 30 is 220 [mm], and the distance from the document leading edge position O to the document length sensor 16 is 330 [mm]. And The document length sensors 15 and 16 output an ON signal when a document is present at the sensor position (hereinafter simply referred to as “ON”), and output an OFF signal when there is no document (hereinafter simply referred to as “ OFF ”). At this time, when the document length sensor 15 is OFF and the document length sensor 16 is OFF, the CPU (A) 801 can determine that the length in the document transport direction (sub-scanning direction) is less than 220 [mm]. . In addition, when the document length sensor 15 is ON and the document length sensor 16 is OFF, the CPU (A) 801 has a length in the document transport direction (sub-scanning direction) of 220 [mm] or more and less than 330 [mm]. It can be judged. Further, the CPU (A) 801 can determine that the length in the document transport direction (sub-scanning direction) is 330 [mm] or more when the document length sensor 15 is ON and the document length sensor 16 is ON.

  The CPU (A) 801 determines the size of the original by combining the length of the original detected during conveyance by the above-described means and on the original tray 30 with information on the original width that can be detected by the original width sensor 14.

  The CPU (A) 801 is connected to the LED 203 (203a, 203b) of the optical scanner unit 202 and the image reading sensor 208 in order to realize an image reading function. The CPU (A) 801 performs shading processing and various filter processes on the image data read by the image reading sensor 208 in the image processing unit (A) 807, and then sends the image data to the image processing controller unit 300 via the image communication unit 302. Send. Further, the CPU (A) 801 adjusts the vertical synchronization signal serving as the reference of the leading edge of the document image data and the horizontal synchronizing signal serving as the reference of the pixel leading edge of one line in accordance with the document reading timing, and passes the command communication unit 301 to the image processing controller unit. 300 is notified.

  The image processing controller unit 300 includes a CPU (B) 901, a ROM (B) 902, and a RAM (B) 903, and exchanges data regarding image reading control with the CPU (A) 801 via the command communication unit 301. I do. The image data processed by the image processing unit 807 is transferred to the image processing unit (B) 905 in the image processing controller unit 300 via the image communication unit 302 and subjected to predetermined image processing such as color determination. Is stored in the image memory 906. The image processing controller unit 300 includes an operation display unit 904, and interface control with the user is performed by the CPU (B) 901 via the operation display unit 904. The CPU (B) 901 receives information input to the operation display unit 904 by the user, and processes input information such as a reading job start.

<Abnormality detection method for document length sensor>
Next, control for detecting whether the document length sensor 15 is in an abnormal state, notification to the user at the time of abnormality determination, and document conveyance control will be described with reference to FIGS. 1 to 10, 13, and 15. FIG. To do. In the following description, an example of reading one side of a document will be shown. Further, the abnormal state here is a state in which paper dust or dust is accumulated on the sensor and the presence or absence of paper cannot be normally detected.

  A method for detecting the size of a document placed on the document tray 30 will be described. FIG. 3 is a view of the image reading apparatus 1000 as viewed from above. When the user places an original on the original tray 30, the original guide plates 25A and 25B are set in accordance with the original width (position of the end in the width direction of the original). The document width sensor 14 shown in FIG. 2 is configured to detect the width (length in the width direction of the document) between the document guide plates 25A and 25B. The CPU (A) 801 can detect the width of the document set on the document tray 30 (length in the width direction of the document) by referring to the value that can be acquired from the document width sensor 14. The document width sensor 14 is connected to a variable resistor whose resistance value changes according to the width between the document guide plates 25A and 25B. The CPU (A) 801 detects the width of the set document by referring to the value obtainable from the document width sensor 14 through the AD converter. As the document length sensor, a flag type that detects a document that contacts the document tray 30 and an optical sensor that detects a document that is separated from the document tray 30 can be selectively used. A document that is separated from the document tray 30 refers to a document that is placed on the document tray 30 in the shape of a mountain, for example, as shown in FIG. It can also be used to detect curled (curved) documents. In this embodiment, an optical sensor is used for the document length sensor 15 and a flag type sensor is used for the document length sensor 16. The CPU (A) 801 uses the signals from the document length sensors 15 and 16 and the signal from the document width sensor 14 to adjust the size of the document based on the size determination information recorded in the ROM (A) 802 in advance. judge.

  4 and 5 are flowcharts showing the abnormality determination of the document length sensor 15 by the CPU (A) 801 and the control at the time of abnormality.

  When the CPU (A) 801 determines in the flowchart of FIG. 4 that an image reading signal has been received from the image processing controller unit 300 (YES in S101), it moves the optical scanner unit 202 to the position of the shading white plate 210 (S102). The CPU (A) 801 can move the optical scanner unit 202 to the above position by controlling the optical motor 804 while managing the number of drive pulses. Next, after the LED 203 (203a, 203b in FIG. 2) of the optical scanner unit 202 is turned on, the image processing unit 807 performs shading correction (S103). The shading correction is a process for correcting variations in the amount of received light in the image reading sensor 208 based on the amount of light from the white plate. After the shading is completed, the optical scanner unit 202 is moved to the reading position below the surface flow reading glass 201 near the read roller 7 (S104). The reading start signal is transmitted from the image processing controller unit 300 only when the document presence / absence detection sensor 10 is in the ON state.

  Next, the CPU (A) 801 detects the size of the document on the document tray 30 (S105). The size of the original is determined by a combination of the detection results of the original width sensor 14 and the original length sensors 15 and 16. The document length at this time is referred to as document length A. The CPU (A) 801 determines the image reading area of the document based on the size of the document determined on the document tray 30 (see S105). The case where it is determined that the document length sensor 15 is abnormal will be described later.

  FIG. 6 shows a size determination table when the CPU (A) 801 determines the document size according to the detection results of the document width sensor 14 and the document length sensors 15 and 16. The classification of the detection results by the document width sensor 14 is described in the row direction, and the detection results of the document length sensors 15 and 16 are described in the column direction.

  For example, when the document width sensor 14 is an A / D conversion type sensor and the detection result detects 210 [mm], it is determined that the document width section is a section of 4. Here, when both the document length sensor 15 and the document length sensor 16 detect OFF (no document), the document size is determined to be A5 size. On the other hand, when the document width sensor 14 detects 210 [mm] and the document length sensor 15 detects ON (there is a document), the document size is determined to be A4R size.

  The abnormal state of the document length sensor 15 includes the following abnormal state 1 and abnormal state 2 as described above in the problem. The abnormal state 1 of the document length sensor 15 is an abnormal state in which the document length sensor 15 remains OFF regardless of the presence or absence of the document when the light emitting unit 17 cannot emit light (FIG. 13). The abnormal state 2 of the document length sensor 15 is an abnormal state in which the state of the document length sensor 15 remains ON regardless of the presence or absence of the document when the light receiving unit 18 remains receiving light (FIG. 15). It is. If the document length sensor 15 is in any of the above-described abnormal states, a document having the same document width but a different document length may be erroneously detected. In the present embodiment, A4R and A5 having the same document width (210 mm) and different document lengths, and LTRR and STMT having the same document width (219.5 mm) and different document lengths will be described as an example.

  Next, the CPU (A) 801 determines whether the document length sensor 15 is in the abnormal state 1 in S106 to S109. As an abnormality detection method for the abnormal state 1, as shown in FIG. 7, when a document is placed on the document tray 30 and the signal from the sensor is as follows, the CPU (A) 801 operates the document. The long sensor 15 determines that there is an abnormality. That is, the document length sensor 15 is OFF when the document presence / absence detection sensor 10 on the downstream side of the document tray 30 (the reading start signal has been received in S101) is ON and the upstream document length sensor 16 is ON. The CPU (A) 801 determines that the document length sensor 15 is abnormal.

  The CPU (A) 801 determines that the document length sensor 15 is abnormal when the upstream document length sensor 16 is ON (YES in S106) and the document length sensor 15 is OFF (YES in S107). The erroneous detection information 1 is stored on the RAM (A) 802 (S108). The false detection information 1 is used for determination of user notification at the time of abnormality described later.

  If the upstream document length sensor 16 is ON (YES in S106) and the document length sensor 15 is ON (NO in S107), it is determined that the document length sensor 15 is normal, and erroneous detection information on the RAM (A) 802 is detected. 1 is erased (S109).

  Next, when the CPU (A) 801 determines that the cleaning alarm status information on the RAM (A) 802 is ON or the erroneous detection information 1 is stored (YES in S110), The irregular size mode is set (S111). Here, the specific paper width size is a paper width size in which the determination of the document size changes depending on whether the document length sensor 15 is ON or OFF. In the present embodiment, for example, the case where the paper width size is larger than 196 mm and 214 mm or less (A4R and A5), and the case where the paper width size is larger than 214 mm and 236 mm or less (LTRR and STMT) can be mentioned. The cleaning alarm status information is a status that is turned on when the document length sensor 15 is abnormal, and a setting method will be described later.

  Next, the CPU (A) 801 determines whether or not the document operates in the irregular size mode (S112). If it is not the irregular size mode (NO in S112), the RAM (A) 802 secures a memory amount (storage area) corresponding to the size of the document detected in S105. On the other hand (S113), in the case of the irregular size mode (NO in S112), a memory amount (storage area) corresponding to the maximum document length is secured in the RAM (A) 802 (S114). This is to prevent the image from being lost when the document length A is different from the actual document length. As a result, even when the document length sensor 15 is in an abnormal state, the user can flow a job, so that the occurrence of downtime can be reduced. In the irregular size mode, the paper size (document length B) is determined by counting the drive pulses of the separation motor 805 (pulse motor) during the time from the ON to the OFF of the conveyance sensor (registration sensor 11). As a method for detecting the paper size, the number of drive pulses counted by the separation motor 805 for the time from when the lead sensor 12 is turned on to when the registration sensor 11 is turned off, and the position of the lead sensor 12 and the registration sensor 11 in the sheet conveyance direction. The paper size may be determined from the difference.

  The CPU (A) 801 determines the image reading area of the document based on the document size determined from the time when the conveyance sensor (registration sensor 11) is turned on to off. After performing S113 / S114, the flow proceeds to the flowchart of FIG.

  In the case of the irregular size mode, the RAM (A) 802 secures a memory amount (storage area) for the maximum document length. Therefore, compared with the case where the document size is determined on the document tray 30, the irregular size mode is less productive when performing continuous image reading of the document. This is because the storage area of the RAM (A) 802 for reading the next image may be insufficient in the irregular size mode, and in this case, it is necessary to wait until the completion of the previous image reading.

  In the flowchart of FIG. 5, the CPU (A) 801 starts conveying the document (S115). The conveyance of the original is realized by driving the separation motor 805 to lower the paper feed roller 1 to the original surface and rotating the separation upper roller 2 and the drawing roller 4.

  Next, after the leading edge of the document reaches the registration sensor 11 and detects that the registration sensor 11 is turned on (YES in S116), the CPU (A) 801 detects the document length B while being conveyed. Counting is started (S117). As described above, by counting the driving pulses of the separation motor 805 (pulse motor), the paper length of the document being conveyed (length in the document conveyance direction) is detected.

  Next, the CPU (A) 801 detects that the leading edge of the document reaches the lead sensor 12 and detects that the lead sensor 12 is ON (YES in S118). Thereafter, the CPU (A) 801 counts the distance from the ON of the read sensor 12 to the reading position, and detects the timing when the leading edge of the document reaches the reading position (S119). That is, the distance from the ON position to the reading position of the read sensor 12 is measured by counting the driving pulses of the reading motor 806 (pulse motor) while the document is being conveyed, and the timing when the leading edge of the document reaches the reading position is detected. The image can be read from the leading edge of the document at the timing when the leading edge of the document reaches the reading position.

  Next, the CPU (A) 801 starts reading by the optical scanner unit 202 (S120). The CPU (A) 801 transfers the image data read by the optical scanner unit 202 to the image processing controller unit 300 through the image communication unit 302 for each line in synchronization with the vertical synchronization signal and the horizontal synchronization signal.

  Next, after detecting that the registration sensor 11 is OFF (YES in S121), the CPU (A) 801 calculates the document length B from the paper length detection counter described above. (S122).

  Next, the CPU (A) 801 compares the document length A detected on the document tray 30 with the document length B detected while being conveyed (S123). If the document length A is different from the document length B (YES in S123), the reading start signal is received with the object 19 placed on the document length sensor 16 (the document length sensor 16 is ON) as shown in FIG. It can be judged that the possibility is high. Therefore, the abnormality detection process (S106 to S109) in the abnormal state 1 is determined to be invalid, and the erroneous detection information 1 on the RAM (A) 802 is deleted (S124).

  Next, the CPU (A) 801 detects the OFF of the lead sensor 12 (YES in S125), and then completes reading of the image after carrying a predetermined distance (S126).

  Then, the CPU (A) 801 determines whether or not there is a next original (S127). Presence / absence of the next original is determined by the original presence / absence detection sensor 10. If there is a document on document tray 30 (YES in S127), the process returns to step S115, and the next document is conveyed.

  On the other hand, if there is no document on the document tray 30 (NO in S127), it is determined in S128 to S133 whether the document length sensor 15 is in the abnormal state 2. As an abnormality detection method for the abnormal state 2, as shown in FIG. 9, when the final document sheet is ejected from the document tray 30 and the signal from the sensor is as follows, the CPU (A) 801 detects the document length sensor 15. Is judged abnormal. That is, when the document length sensor 15 is ON when the final document sheet is discharged from the document tray 30 and the document presence / absence detection sensor 10 is turned OFF, the CPU (A) 801 indicates that the document length sensor 15 is abnormal. Judge. Regarding the abnormal state 2, when the abnormality determination continues for a predetermined number of times, it is determined that the document length sensor 15 is abnormal.

  Regarding the abnormal state 2, in this embodiment, since the user may place a document on the tray immediately after the final sheet is discharged from the document tray 30, the document length sensor 15 is detected when the abnormal state continues a plurality of times. Is determined to be abnormal, but it may be determined to be abnormal once.

  If the document presence / absence detection sensor 10 is OFF (YES in S127) and the document length sensor 15 is ON (YES in S128), the CPU (A) 801 may determine that the document length sensor 15 is abnormal. It is determined that there is, and the false detection counter is increased (S129). If the erroneous detection counter exceeds the predetermined value (YES in S130), the erroneous detection information 2 is stored on the RAM (A) 802 (S127). The false detection information 2 is used for determination of user notification at the time of abnormality, which will be described later.

  When the document length sensor 15 is OFF (NO in S128), it is determined that the document length sensor 15 is normal, the false detection counter is cleared (S132), and the false detection information 2 on the RAM (A) 802 is deleted (S132). S133).

  Next, CPU (A) 801 determines whether or not document length sensor 15 is abnormal, and notifies a cleaning alarm. If the false detection information 1 (abnormal state 1) or the false detection information 2 (abnormal state 2) is set (YES in S134), the CPU (A) 801 determines that the document length sensor 15 is in an abnormal state, so that the cleaning alarm The status is turned on (S135). Then, the CPU (A) 801 notifies the image processing controller unit 300 of cleaning alarm information (S136). When the image processing controller unit 300 receives the cleaning alarm information, the CPU (B) 901 displays a screen as shown in FIG. 10 on the operation display unit 904. As a result, the user can notice an abnormality in the document length sensor 15. In the screen shown in FIG. 10, when the user presses the OK button after cleaning, the warning disappears and the user can start reading. However, if the cleaning is not sufficient, a warning is displayed because the flags of the erroneous detection information 1 and 2 are again raised.

  As described above, when the cleaning alarm status is ON (or when erroneous detection information 1 is stored), the operation is switched to the irregular size mode from S110 to S114. If false detection information 1 (abnormal state 1) and false detection information 2 (abnormal state 2) are not set (NO in S134), it is determined that the document length sensor 15 has returned to normal and the cleaning alarm flag is turned OFF. (S137). Then, the ADF reading job is terminated.

  In this embodiment, even if paper dust or dust accumulates on the optical document length sensor on the document tray, it is possible to detect an abnormality in the document length sensor and notify the user. Further, when an abnormality of the document length sensor is detected, it is possible to control to change to a mode in which the registration sensor detects the size of the document while conveying the document.

  Accordingly, even if paper dust or dust accumulates in the optical document length sensor and the sensor becomes abnormal, the user can know the abnormality of the sensor. Further, the user can continue the image reading job. Therefore, it is possible to provide an easy-to-use image reading apparatus that suppresses the occurrence of downtime.

  In the above-described embodiment, the image reading apparatus alone having the ADF and the image reading unit is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, it may be an image reading apparatus in an image forming apparatus such as a copying machine or a facsimile machine further having an image forming unit. The same effect can be obtained by applying the present invention to the image reading apparatus in these image forming apparatuses.

S ... Document bundle 10 ... Document presence / absence detection sensor 11 ... Registration sensor 12 ... Read sensor 13 ... Discharge sensor 14 ... Document width sensors 15, 16 ... Document length sensor 30 ... Document tray 100 ... ADF
DESCRIPTION OF SYMBOLS 200 ... Image reading part 201 ... Sink reading glass 202 ... Optical scanner unit 204a, 204b, 204c ... Mirror 208 ... Image reading sensor 300 ... Image processing controller part 301 ... Command communication part 302 ... Image communication part 310 ... Controller 801 ... CPU (A)
802 ... ROM (A)
803 ... RAM (A)
804 ... Optical motor 805 ... Separation motor 806 ... Reading motor 807 ... Image processing section (A)
901: CPU (B)
902 ... ROM (B)
903 ... RAM (B)
905 ... Image processing unit (A)
904 ... Operation display unit 906 ... Image memory 1000 ... Image reading apparatus

Claims (9)

In an image reading apparatus that feeds a sheet placed on a tray and reads an image of a conveyed sheet at a reading position,
A sheet presence / absence detection sensor for detecting the presence / absence of a sheet on the tray;
An optical first sheet length detection sensor provided on the upstream side in the sheet conveyance direction from the sheet presence / absence detection sensor, for detecting the length in the conveyance direction of the sheet placed on the tray;
After conveying the sheet to read the image of the sheets stacked on the tray, the sheet presence / absence detection sensor outputs a signal related to the absence of the sheet, and the first sheet length detection sensor outputs a signal related to the presence of the sheet. A control unit that performs control for notifying the abnormality of the first sheet length detection sensor. In an image reading apparatus that feeds a sheet placed on a tray and reads an image of a conveyed sheet at a reading position,
An optical first sheet length detection sensor for detecting the length in the conveyance direction of the sheet placed on the tray;
A second sheet length detection sensor provided upstream of the first sheet length detection sensor for detecting the length of the sheet placed on the tray in the conveyance direction;
When the first sheet length detection sensor outputs a signal related to the absence of a sheet and the second sheet length detection sensor outputs a signal related to the presence of a sheet, the first sheet length detection is performed. An image reading apparatus comprising: a control unit that performs control for notifying abnormality of the sensor. A storage unit for storing an image of the sheet;
When the image reading is executed in a state where the first sheet length detection sensor outputs a signal related to the absence of a sheet and the second sheet length detection sensor outputs a signal related to the presence of a sheet, the control unit stores the memory. The image reading apparatus according to claim 2, wherein a reading area is read by securing a storage area of a maximum size sheet in a portion. A sheet detection sensor that is provided in a sheet conveyance path and detects a length in a conveyance direction of the sheet conveyed from the tray;
The controller, after the first sheet length detection sensor outputs a signal related to the absence of a sheet and the second sheet length detection sensor outputs a signal related to the presence of a sheet, The length in the sheet conveyance direction determined by the detection result of the sheet detection sensor is different from the length in the sheet conveyance direction determined by the detection result of the first sheet length detection sensor and the second sheet length detection sensor. 4. The image reading apparatus according to claim 2, wherein control for notifying the abnormality of the first sheet length detection sensor is not performed. A sheet width detection sensor for detecting a length in the width direction orthogonal to the sheet conveyance direction on the tray;
The said control part determines the image reading area | region of a sheet | seat based on the detection result of the said 1st sheet length detection sensor and the said sheet width detection sensor, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Image reading device. A sheet detection sensor that is provided in a sheet conveyance path and detects a length in a conveyance direction of the sheet conveyed from the tray;
When the control unit determines that the first sheet length detection sensor is abnormal, the control unit determines an image reading region of the sheet based on the detection result of the sheet width detection sensor and the sheet detection sensor. The image reading apparatus according to claim 5, wherein:   7. The image reading according to claim 1, wherein the control unit determines that an abnormality is detected when abnormality detection of the first sheet length detection sensor continues for a predetermined number of times. apparatus. A display unit for displaying to the user;
The control unit notifies the abnormality of the first sheet length detection sensor by displaying the abnormality of the first sheet length detection sensor on the display unit. The image reading apparatus according to item. The image reading apparatus according to any one of claims 1 to 8,
An image forming apparatus comprising: an image forming unit that forms an image based on image information acquired by the image reading apparatus.

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