JP2006154586A - Original reader for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that an image forming apparatus can not easily cope with environment under which the apparatus is put because the exchange of a flag member or the mechanical adjustment thereof is required in order to change detection timing to detect original size in constitution where the mechanical flag member turns on/off a photointerrupter according as an original cover member is opened/closed as a method for deciding the detection timing in the case of detecting the size of an original on a platen glass in the original reading part of an image forming apparatus. <P>SOLUTION: By providing an acceleration sensor in the original cover member and obtaining the opening angle of the original cover member from output from the acceleration sensor, the timing to detect the original size can be adjusted by software. Associated with such adjustment, adjustment at assembly/shipping in a factory is not required, and the number of parts is reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a document reading unit of an image forming apparatus, and in particular, a document size for detecting a paper size of a document placed on a platen glass according to an opening angle of a document pressing member for pressing the document onto the platen glass. The present invention relates to a document reading device of an image forming apparatus including a detecting unit.

Conventionally, in order to detect the paper size of a document placed on a platen glass in a document reading unit of an image forming apparatus such as a copying machine or a facsimile, a flag member as shown in FIG. Some document size detection processing is performed based on the timing at which the flag blocks the photo interrupter at a predetermined angle by closing the document pressing member (denoted as DF in the drawing) provided on the pressing member side. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 11-133523

  In the document size detection process using such a method, when the apparatus is installed near a window or in a place where there is a lot of reflected light, disturbance light enters the light receiving portion of the document size detection sensor, thereby reducing the document size. In order to solve this problem, the timing for performing the document size detection process is changed. For example, in an environment where the size of the document is erroneously detected due to the sun, the timing for starting the document size detection is changed. There is a coping method in which the size detection is started in a state where the document pressing member is further closed with a delay.

  However, the method of determining the start timing of document size detection by the flag method described above can only deal with a troublesome method such as replacing the flag member or adjusting the attachment angle.

  In addition, at the time of assembling / shipping the device, the flag member must be attached at a predetermined angle, and the man-hour and the cost of the member are generated accordingly.

  The present invention is an original reading apparatus of an image forming apparatus characterized by the following configuration.

  (1) A document reading device of the image forming apparatus includes a flat and transparent document support member on which a document is placed, a document pressing member that closely contacts the document on the document support member, the document pressing member includes acceleration detection means, A setting for setting and storing the inclination of the document pressing member at a certain point of time as a reference state; and a means for detecting the inclination of the document pressing member based on the output of the acceleration detection means. And an opening angle of the document pressing member is detected based on a difference between a reference state inclination of the document pressing member stored in the storage unit and a current inclination obtained from the tilting means. It is characterized by that.

  (2) The document reading device of the image forming apparatus according to (1), further including document size detection means on a side of the document support member facing the document placement surface, wherein the document size detection means includes the acceleration Control is based on the opening angle of the document pressing member derived from the output of the detecting means.

  (3) The document size detection means described in (2) further includes detection timing setting means for switching the document size detection timing with respect to the opening angle of the document pressing member according to the operating environment of the apparatus. Features.

  (4) The acceleration detecting means described in the above (1) or (2) is a biaxial acceleration detecting means capable of detecting acceleration in two directions, and a region having low sensitivity in either one of the axes is the other axis. The inclination of the document pressing member is obtained based on the output.

  In the document reading unit of the image forming apparatus, an acceleration detecting unit is arranged on the document pressing member, and the document size is detected at a set timing according to the opening angle of the document pressing member obtained based on the output of the acceleration detecting unit. By performing the control, it is possible to detect the document size at a timing suitable for the environment where the apparatus is placed without adjusting the mechanical mechanism.

  Further, since the opening angle of the document pressing member is obtained from a difference from the inclination of the reference state, adjustment at the time of assembly / shipment becomes unnecessary, and the number of mechanical components can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic sectional view of an image reading apparatus according to an embodiment of the present invention. In the figure, reference numeral 100 denotes an image reading apparatus main body. Reference numeral 101a denotes a platen glass as a document placing table, and 101b denotes a platen glass as a document reading window when using DF, which will be described later. An optical unit 102 includes a document illumination lamp 103 for illuminating a document, an image sensor unit 104 for reading an image, and the like.

  An optical unit cable 105 supplies power to the optical unit 102 and transmits image data read by the image sensor unit 104 to a control unit (not shown). In this cross-sectional view, the image sensor unit 104 uses a contact line sensor composed of a group of image sensors arranged in a line in the drawing depth direction having substantially the same length as the depth width of the platen glass 101.

  When reading a document image placed on 101a, the optical unit 102 is reciprocated in a predetermined direction (left and right direction in the drawing) by a motor (not shown), and the document surface is placed on the document illumination lamp 103 in the forward path therebetween. , And the reflected image is received by the image sensor unit 104, whereby the document image is converted into an electrical signal.

  Reference numeral 110 denotes an automatic document feeder (DF). The pickup roller 112 and the separation roller 113 separate only one uppermost document from the document stack placed on the document table 111, the registration roller 114 adjusts the leading edge of the document, and the first A document is fed by the document feed roller 115. The original is passed over the platen glass 101b by the platen roller 116, and is sent to the paper discharge unit by the second transport roller 117.

  At that time, the optical unit 102 is moved to a predetermined position below the platen glass 101b. In this way, as the document moves on the optical unit 102 having a fixed position, the reflected light of the document surface illuminated by the document illumination lamp 103 is received by the image sensor unit 104, and the document image is converted into an electrical signal. Converted.

  At this time, in consideration of the order of conversion into electric signals in the line sensor of the image sensor unit 104, the sequence of image data at the time of document fixed reading using the platen glass 101a is different from that at the time of document flow reading using the platen glass 101b. It should be noted that the arrangement of the image data is a left and right mirror image when viewed in the original image.

  When the reverse flapper 118 is open in the paper discharge direction (in the state where it is pulled up in the drawing), the original conveyed to the paper discharge unit is guided to the paper discharge reverse roller 119, and is out of the machine for paper discharge. Is discharged to the paper discharge tray 120. Alternatively, when the back side of the original is subsequently read, the reverse paper discharge roller 119 conveys the original until it passes through the reverse flapper 118, where the reverse flapper 118 is closed in the paper discharge direction (the state where the flapper is lowered in the figure). ), And the reverse paper discharge roller 119 is rotated in the reverse direction, the original enters the transport path again, and the back side image is read. If the original is directly discharged to the paper discharge tray 120 after the back side image is read, the original on the original platen 111 will not be aligned (the front and back sides will be reversed). The original is reversed again by the paper discharge roller 119, and the conveyance path is preliminarily fed (the original is not read), and then discharged to the paper discharge tray 120.

  Reference numeral 121 denotes a document detection sensor that detects whether or not there is a document at a corresponding position on the platen glass. These are used to determine the size of the document in the longitudinal direction (left and right direction in the figure) and are not shown in the figure, but the document detection sensor for determining the size of the document in the back direction (direction perpendicular to the figure) Also arranged.

  Reference numeral 122 denotes an acceleration sensor for detecting the opening angle of the DF. Details will be described later.

  FIG. 2 is a block diagram showing the configuration of the image reading apparatus according to the embodiment of the present invention.

  A CPU 201 controls the image reading apparatus main body 100.

  Reference numeral 202 denotes an HP sensor that detects whether the optical unit 102 is at a reference position, that is, a home position (HP), and inputs a signal to the CPU 201.

  A motor 203 drives the optical unit 102 based on an instruction from the CPU 201.

  An external IF 204 is an interface (IF) for communicating between the controller and the image reading apparatus when connected to the controller. A command is issued from the controller to the CPU 201 via the external IF 204. Alternatively, a command from the CPU 201 is notified to the controller. The image data read by the image reading device is transmitted to the controller.

  Reference numeral 206 denotes an image memory, which stores image data read by the image sensor unit 104.

  An image processing unit 207 performs image processing on image data stored in the image memory 206 based on an instruction from the CPU 201.

  In addition, the CPU 201 of the image reading apparatus main body 100 is connected to the document feeder (DF) 110 to control the DF 110.

  103 and 104 are the document illumination lamp and image sensor unit described in FIG. 1. The document illumination lamp 103 is turned on / off according to an instruction from the CPU 201, and the image sensor unit 104 is placed in the sensor area according to the instruction from the CPU 201. The imaged optical data is converted into electronic data and recorded in the memory unit 206 via the CPU 201.

  121 is a document detection sensor comprising a plurality of sensors described in FIG. 1, and 122 is an acceleration sensor.

  FIG. 3 is a schematic view of the image reading apparatus shown in FIG. 1 as viewed from the side.

  The right direction in the figure is the front of the main body, and the DF 110 opens and closes around the back hinge.

  Reference numeral 122 denotes an acceleration sensor, which is arranged in a cover in an actual machine and cannot be seen from the outside, but is schematically illustrated here.

  The acceleration sensor 122 is a biaxial acceleration sensor in the X direction and the Y direction perpendicular thereto, and the detection axis is the X axis in the back hinge direction parallel to the bottom surface of the DF 110, and the Y axis in the direction perpendicular to the bottom surface of the DF 110. It is arranged to come. Therefore, if the acceleration in the X direction is gx, the acceleration in the Y direction is gy, the state where the DF 110 is closed is defined as 0 °, and the opening angle of + in the direction in which the DF 110 is opened, then FIG. As shown, gx is an output of a sin curve and gy is an output of a cos curve. Therefore, the opening angle of the DF 110 can be obtained from the output of the acceleration sensor.

  In this embodiment, using a two-axis acceleration sensor, if the output value of one axis exceeds a certain threshold value, the average of both if both outputs are below the threshold value based on the remaining output value The opening angle of the DF 110 is obtained based on the value.

  This is because if gx is a region where the open angle is large, and if gy is a region where the open angle is small, the change in sensor output is small with respect to the change in tilt, and therefore the measurement error increases.

  However, if it is determined that the detection accuracy may be poor in those areas, it is possible to reduce the cost by replacing with a uniaxial acceleration sensor.

  In the present embodiment, the case where the two axes are arranged in the depth direction and the gravity direction with the DF closed is described, but the axis direction is not limited thereto.

  FIG. 5 is a control flow diagram relating to document size detection as shown in the present embodiment.

  First, in step S501, it is checked whether or not the reference angle has been set. If it has been set, the process proceeds to step S503. If it has not been set, the reference angle is set in step S502. The reference angle is a DF opening angle (hereinafter referred to as an angle) obtained by the output of the acceleration sensor when the DF is closed. In the present invention, the angle of the DF is the acceleration sensor at that time. Calculation is based on the relative relationship between the output and the output of the acceleration sensor in the reference state.

  In other words, it is possible to detect the angle of the DF even if the accuracy of attaching the direction of the detection axis when arranging the acceleration sensor is not strict. Further, when an inclination of a predetermined value or more is detected at the time when the reference angle is set, it is possible to warn that the installation is abnormal.

  In step S503, it waits for the DF to be opened. Here, it is determined that the DF is opened when the angle of the DF becomes larger than the predetermined value θ1.

  After detecting the DF opening, it waits for the DF to start closing in step S504. Here, it is determined that the DF starts to close when the angle of the DF becomes smaller than a predetermined value θ2 (θ1> θ2).

  In step S505, it is detected that the DF has started to close, and the document size detection operation is started. The mechanism of document size detection will be described later.

  The document size determination is repeatedly performed while the DF is closed, and the DF is completely closed (step S506). Alternatively, a predetermined time elapses at a certain angle of DF (step S507). Alternatively, the document size is determined (step S509) when the reading operation is started (step S508). The document size detection operation stops when the document size is determined. Incidentally, the document size is determined under the condition of step S507 because, for example, the DF may not be closed when reading a book document.

  Once the document size is determined, the size is held until the DF starts to open again (unless the power is turned off or the power saving mode is set). The fact that the DF has begun to open is determined by the fact that the angle of the DF has become larger than a predetermined value θ3 (θ2> θ3, and θ3 is larger than the DF angle for a general book document assumed in step S507). (Step S510).

  Upon receipt of the opening of the DF, the detected document size is cleared (step S511), and the process returns to the waiting state of step S503.

  Alternatively, when the DF starts to open in the document size detection operation state (step S512), the document size detection operation is stopped (step S513), and the document size detected at that time is cleared (step S513). S511), the process returns to the waiting state of step S503. The DF angle at which it is determined in step S512 that the DF has started to open is equal to the aforementioned θ3.

  Hereinafter, the mechanism of document size detection will be described.

  FIG. 6 shows an example of the arrangement of the document size detection sensors, and shows the arrangement of the sensors when the platen glass is viewed from above. Two document size detection sensors are arranged in the line direction (main scanning direction) of the image sensor and three original size detection sensors in the moving direction (sub-scanning direction) of the optical unit. A3R, B4R, A4R are combined depending on the detection result of each sensor. , B5R, A4, and B5 standard size originals (R means landscape orientation) can be detected.

  FIG. 7 is a schematic view of one document size detection sensor as viewed from the side. 700 is a sensor body, 701 is a light emitting unit of the sensor, and 702 is a light receiving unit of the sensor. Reference numeral 101 denotes a platen glass, and reference numeral 703 denotes a DF document pressing portion.

  The sense light emitted from the sensor light emitting unit 701 is reflected on the original surface when there is a document on the platen glass 101 and is input to the sensor light receiving unit 702, but there is no reflection when there is no document. Therefore, no light is received by the sensor light receiving unit 702. However, since the document holding portion 703 of the DF is white, when the DF is closed, the sensor determines that there is a document regardless of whether there is a document.

  Therefore, when there is a document on the platen glass 101, the output of the sensor changes from 1 (with a document) to 1 from the start of document size detection until the DF is closed, and there is no document. In this case, 0 (no original) → 1 changes.

  In addition, if a black part on the document has come out in the area where the sensor determines whether or not there is a document, the sensor output will output no document even though there is a document. The change in the sensor output from the start time until the DF is closed becomes 0 → 0, and the sensor output that should be 1 by closing the DF remains 0, so there is also a document at this position. I can judge.

  From these facts, it can be seen from the change in the output of each sensor that there is no original in the place where the output of the sensor has changed, and the standard size of the original is determined by the combination (1 → It cannot be changed to 0).

  In the present embodiment, a description has been given of a configuration having a document detection sensor in both the main scanning direction and the sub-scanning direction. Conventionally, in the main scanning direction, a configuration of CCD size detection that detects a document size using an image reading image sensor. Has also been implemented. However, this method can be similarly implemented with respect to control of document size detection timing.

  FIG. 8 is an example of an operation unit screen for adjusting θ1, θ2, and θ3 described in the flowchart of FIG.

  As described above, the relation of θ1> θ2> θ3 is established, and it is determined that the DF is opened at θ1, then the DF starts to close, and when the angle reaches θ2, the document size detection is started and the DF is closed. After that, the document size determined as the opening of the DF is cleared when the angle becomes θ3 again.

  These angles have different optimum values depending on the use environment of the user.

  For example, as described with reference to FIGS. 6 and 7, since the document size is determined by the combination of light entering the light receiving portions of the respective document detection sensors, the apparatus is installed near a window or in a place where there is a lot of reflected light. This increases the possibility that the document size will be erroneously determined due to disturbance light entering the light receiving portion of the sensor. In such an environment, by reducing θ2, the accuracy of erroneous determination can be lowered by delaying the document size detection timing.

  Further, in an environment where a very thick book document is read, it is necessary to increase the value of θ3 so that the document size is not cleared by mistake.

  Alternatively, depending on the height of the user, the operability may be improved by adjusting the value of θ1 to lower the angle at which it is determined that the DF is opened.

  The operation screen shown in FIG. 8 is an adjustment screen for setting θ1, θ2, and θ3 optimum for such a user environment.

  An operation screen 800 is a liquid crystal touch panel, 801 is an OK button for confirming the setting, and 802 is a cancel button for canceling the setting.

  Reference numerals 803, 804, and 805 denote indicators that indicate approximate set angles of θ1, θ2, and θ3, respectively, and also serve as selection buttons for adjusting which angle.

  Reference numerals 806 and 807 denote angle adjustment buttons, which increase / decrease set values of θ1, θ2, and θ3 corresponding to the buttons 803, 804, and 805 selected by the user.

1 is a schematic cross-sectional view of a document reading device of an image forming apparatus according to an embodiment of the present invention. Control block diagram of document reading apparatus according to the present invention Explanatory drawing of obtaining DF slope from output of acceleration sensor Relationship between DF tilt and acceleration sensor output Flow chart showing the flow of document size detection control The figure which shows the example of arrangement | positioning of a document detection sensor Explanatory drawing showing the mechanism of document size detection The figure which shows the example of an operation part screen for detection angle adjustment The figure which shows the DF angle detection method of a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Document reading apparatus 101 Platen glass 102 Optical unit 104 Image sensor part 110 Automatic document feeder (DF)
121 Document detection sensor 122 Acceleration sensor

Claims (4)

In a document reading device of an image forming apparatus having a flat and transparent document supporting member for placing a document and a document pressing member for bringing the document into close contact with the document supporting member,
The document pressing member includes acceleration detecting means,
A document pressing member inclination detecting means for obtaining an inclination of the document pressing member based on an output of the acceleration detecting means;
And a setting unit and a storage unit for setting and storing the inclination of the document pressing member at a certain time as a reference state,
An image forming apparatus that detects an opening angle of the document pressing member based on a difference between a reference state inclination of the document pressing member stored in the storage unit and a current inclination obtained from the tilting unit. Original reading device. The document reading device of the image forming apparatus according to claim 1 further includes document size detecting means on a side of the document support member facing the document placement surface,
2. The document reading device of an image forming apparatus according to claim 1, wherein the document size detecting unit is controlled based on an opening angle of the document pressing member derived from an output of the acceleration detecting unit.   3. The document size detection means according to claim 2, further comprising detection timing setting means for switching the document size detection timing with respect to the opening angle of the document pressing member in accordance with the operating environment of the apparatus. A document reading device of the image forming apparatus described.   The acceleration detecting means according to claim 1 or 2 is a biaxial acceleration detecting means capable of detecting acceleration in two directions, and the region having low sensitivity in one of the axes is based on the output of the other axis. 3. The document reading device for an image forming apparatus according to claim 1, wherein an inclination of the document pressing member is obtained.

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