JP2009272806A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus reducing the state where a user feels dazzled by remarkably reducing an apparent luminance when a platen cover is in an opened state. <P>SOLUTION: The image reading apparatus is provided with: a flat bed 2 having a platen cover 3 and allowing an original document to be placed; a reading/scanning section 10 for irradiating the original document with a light to execute reading/scanning of the original document while moving a light source section 8; and a control section 100 controlling the light source section 8 and the reading/scanning section 10. When the original document reading/scanning operation is executed with the platen cover 3 opened, the control section 100 sets the reading cycle of a line sensor 9 so that the same luminance and exposure quantity as those in executing reading/scanning, is obtained with the platen cover 3 closed, and sets the light-off time of the light source section 8 therein, and controls the reading/scanning section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement of a flat bed type image reading apparatus for optically reading a document.

  In general, a flat bed type image reading apparatus for optically reading a document includes a flat bed on which the document is placed and a platen cover that covers the flat bed so as to be freely opened and closed. Further, a reading scanning unit having a light source unit that moves along the flat bed and irradiates a document is provided.

  Conventionally, a fluorescent tube or a cold cathode tube has been used to illuminate the original of such a flatbed image reading apparatus. However, in recent years, for the purpose of shortening the exposure time of a photographing unit for photographing a document and improving the reading speed, an LED array with higher brightness has been used for the light source unit.

  However, when reading an original with an image reading apparatus using a high-luminance LED array, if the original is read without closing the platen cover (so-called sky shot), a part of the light from the light source is There was a problem that it felt dazzling in my eyes.

  In the case of a conventional fluorescent tube or cold cathode tube light source, the amount of light is not so high, and even if the light source is viewed, there is no such problem. However, when the light source is a high-intensity LED array as in recent years, there is a problem that the user feels very dazzling.

As a technique for solving such a situation, for example, Patent Document 1 discloses a technique for inserting a time during which the light source is turned off in the reading interval of one page of a document. That is, in the technique of Patent Document 1, the time during which the light is turned off is inserted between the originals, and the reading time including the lighting time and the light-off time is compared with the reading time when the platen cover is closed. Also control to be longer. In addition, by inserting the time during which the light source is turned off in the reading interval of one page of the document in this way, the apparent luminance of the light source is lowered so that the user does not feel dazzling.
JP-A-5-249812

  However, the technique disclosed in Patent Document 1 described above is not only a technique related to an analog copying machine, but also only inserts a time during which the light source is turned off in a relatively long time such as a reading interval of one page of a document. Met. Therefore, the substantial apparent luminance is almost the same as when the platen cover is closed, and the effect of reducing the feeling of dazzling by the user is small.

  The present invention has been made in view of the above circumstances, and provides an image reading apparatus that can greatly reduce the apparent brightness when the platen cover is in an open state, thereby reducing the situation in which the user feels dazzling.

  In order to solve the above-described object, an image reading apparatus of the present invention has a platen cover that can be freely opened and closed, and moves a line sensor and a light source unit along the flat bed for placing an original, and the flat bed. However, a reading scanning unit for irradiating the original with light to perform reading scanning of the original, and a control unit capable of controlling the light source unit and the reading scanning unit, the control unit opens the platen cover. When performing scanning scanning of a document in a state where the scanning is performed, the scanning cycle of the line sensor is set so that the same brightness and the same exposure amount as when scanning scanning is performed with the plantain cover closed, The reading scanning unit is controlled by setting a time in which the light source is turned off to be incorporated.

  Here, when receiving the document reading command, the control unit determines whether the document reading scan with the platen cover opened or the document reading scan with the plantain cover closed, and the document reading It is preferable to reduce the scanning speed during scanning accordingly.

  The reading control unit includes a pulse motor that moves the light source unit, and the control unit sets the reading cycle of the line sensor to an integer multiple of the pulse of the pulse motor, and the pulse motor The image reading apparatus of the present invention that reduces the movement speed of the light source unit by changing the pulse width accordingly includes a pulse motor 112 that moves the light source unit, and the control unit It is preferable that the moving speed of the light source unit is variably controlled by setting the reading cycle of the line sensor to an integral multiple of the pulse and changing the pulse width of the pulse motor 112.

  According to the present invention, since the turn-off time is added during the reading scanning of the line sensor, the reading scanning speed is slowed down, but the feeling of glare can be eliminated without reducing the amount of light at the time of sky shot. Further, since there is no change in the brightness and exposure amount at the time of reading the line sensor, the shading data can be shared at the time of normal reading and at the time of sky shot.

  Thus, the present invention is particularly suitable for a digital scanner.

  Furthermore, if the scanning speed during document scanning is reduced accordingly, the document can be scanned without stopping the scanning during the extinguishing time.

  And if the reading cycle of the line sensor is set to an integer multiple of the pulse of the pulse motor and the moving speed of the light source unit is decreased accordingly by changing the pulse width, the pulse width of the pulse motor is lengthened. Only the line sensor reading cycle can be lengthened. Further, it is possible to simultaneously reduce the moving speed of the light source unit.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of the invention will be described with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing the configuration of the image reading apparatus 1 according to the embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of the control unit 100 of the image reading apparatus 1.

  Here, the image reading apparatus 1 is assumed to be an office multi-function machine that also serves as a scanner apparatus, a printer apparatus, and a copying apparatus.

  As shown in FIG. 1, the image reading apparatus 1 includes a flat bed 2 on which a document is placed, a platen cover 3 that covers the flat bed 2 so as to be openable and closable, an operation panel 4 provided in front of a main body 21, And a recording paper insertion portion 5 provided on the right side surface of the main body 21.

  Here, the flat bed 2 is constituted by a platen glass provided on the upper surface of the main body 21 of the image reading apparatus 1.

  Further, the platen cover 3 shields the flat bed 2 when reading a document, and is attached to the upper surface of the main body 21 of the image reading apparatus 1 through a hinge 6 so as to be freely opened and closed.

  The hinge 6 is provided with a platen cover state detection unit 7 (FIG. 2) configured by an electric switch or the like that is turned on immediately before the platen cover 3 is closed. The platen cover state detector 7 can detect the open / closed state of the platen cover 3.

  The operation panel 4 includes various operation keys 4b such as a start button 22 for instructing reading start, and a display window 24 including a liquid crystal panel.

  Although not shown in FIG. 1, the image reading apparatus 1 has a reading scanning unit 10 (FIG. 2) built in a main body 21. The reading scanning unit 10 includes a light source unit 8 (FIG. 2) that moves along the flat bed 2 and irradiates a document. The reading scanning unit 10 has a line sensor 9 (FIG. 2) that moves along the flat bed 2 in the same manner as the light source unit 8 and shoots a document with light emitted from the light source unit 8. . The line sensor 9 photographs a document with a CCD (charge coupled device) as a photographing element for photographing the document. The line sensor may be fixed to the housing, and the reflected light from the document may be guided to the line sensor by a carriage on which a mirror is mounted.

  As described above, the reading scanning unit 10 is configured to perform reading scanning of the document by irradiating the document with light while moving the light source unit 8 and the line sensor 9 along the flat bed 2. The movement of the light source unit 8 and the movement of the line sensor 9 are performed by driving the pulse motor 112.

  The control unit sets the reading cycle of the line sensor 9 to an integral multiple of the pulse of the pulse motor 112, and changes the pulse width of the pulse motor 112, thereby changing the moving speed of the light source unit 8 accordingly. Reduce.

  In addition, the image reading apparatus 1 includes a printing unit 11 (FIG. 2) that prints and outputs a read document or the like inside a main body 21.

  Further, the image reading apparatus 1 includes a control unit 100 shown in FIG.

  Here, the control unit 100 includes a communication unit 101 that communicates with a communication device 12 such as a personal computer through a network 13 and the like, and a CPU (Central Processing Unit) 102. Further, a ROM (Read Only Memory) 103 and an SRAM (Static Random Access Memory) 104 are provided. The CPU 102 is connected to the sound generation unit 120 (FIG. 3) via the serial bus 111.

  The control unit 100 also includes a reading control unit 105 that controls reading, and a reading image processing circuit 106 that performs predetermined image processing on image data obtained by reading a document.

  The reading control unit 105 includes a platen cover state detection unit 7, a light source unit 8 provided with a particularly high-luminance LED (light emitting diode) array, and a driver circuit 113 for a motor 112 that controls movement of the light source unit 8. Is connected.

  The reading image processing circuit 106 is connected to the line sensor 9.

  The control unit 100 also includes a printing image processing circuit 107 that performs color space conversion of image data to be printed, and a codec 109 that performs file format conversion on the image data. The control unit 100 also includes an image memory 110 that stores the read image data or image data to be printed.

  Next, with reference to FIG. 3, the control and operation of the image reading apparatus 1 according to the embodiment of the present invention will be described.

  The basic operation of the image reading apparatus 1 is basically the same as that of a conventional office multifunction machine. That is, the scanner device reads a document placed on the flat bed 2 according to the operation of the operation panel 4 and transmits the image data to the communication device 12 through the network 13. Further, the printer device accepts image data together with a print command from the communication device 12 through the network 13, prints the received image data on a recording sheet, and outputs it. Further, the copying apparatus reads a document placed on the flat bed 2 in accordance with an operation on the operation panel 4 and prints the read image data on a recording sheet for output.

  Here, the scanning photographing of the image reading apparatus 1 is performed by reflecting the light emitted from the light source unit 8 by the original while moving the light source unit 8 and the line sensor 9 along the flat bed 2 on which the original is placed. Furthermore, it is made by sequentially guiding the partial image of the original on which the reflected light is formed by guiding it to the line sensor 9 with a reflection mirror or the like. The partial images are connected as image data according to the photographing order.

  Here, control of the light source unit in the control of the control unit 100 will be described. FIG. 3 is a flowchart showing the control procedure of the light source unit of the control unit 100.

  In the control unit 100 of the image reading apparatus 1, as shown in FIG. 3, first, when the start button 22 is pressed in step S1, it is determined in step S2 whether the platen cover 3 is opened. That is, it is determined whether the document reading scan with the platen cover 3 opened or the document reading scan with the plantain cover 3 closed. In the closed state, the process proceeds to step S <b> 3, and normal reading parameters whose period is A are set in the reading control unit 105.

  In step S2, when it is determined that the platen cover 3 is open, the process proceeds to step S4, and a low-speed reading parameter with a period of B is set in the reading control unit 105.

  And it progresses to step S5 and the light source part 8 lights.

  Then, it progresses to step S6 and rotation of the pulse motor 112 is started.

  In step S7, the document is scanned and photographed using the set reading parameters under either of the normal reading with the period A and the low-speed reading with the period B.

  At this time, the reading control unit 105 turns on the light source unit 8 and starts the rotation of the motor 112 via the driver circuit 113. By the rotation of the motor 112, the light source unit 8 moves in parallel along the flat bed 2 from the standby position.

  Here, normal reading and low-speed reading will be described. FIG. 4 is an explanatory diagram for explaining a difference between normal reading and low-speed reading of the light source unit. Here, FIG. 4A is a time chart for normal reading, and FIG. 4B is a time chart for low-speed reading. HSYNC indicates a synchronization period of reading of the line sensor 9, Vled indicates a change in luminance, and M-Clk indicates a driving pulse of the pulse motor 112.

  As shown in FIG. 4A, in the case of normal reading, the luminance Vled remains constant and the lighting state is continued, and two pulses of the pulse motor 112 correspond to the reading period A of the line sensor 9. Yes.

  On the other hand, in the case of low-speed reading, the luminance Vled remains constant as shown in FIG. Further, the light source repeats the turn-on time B1 and the turn-off time B2, and two pulses having a longer pulse width of the pulse motor 112 correspond to the reading cycle B of the line sensor 9.

  As described above, in the case of low-speed reading with a cycle of B, that is, when the document reading scan is executed with the platen cover 3 opened, the control unit 100 performs the reading scan with the plantain cover 3 closed. The brightness is the same as when executing. Further, the lighting time B1 is set to be the same as the time A so that the same exposure amount can be obtained, and the reading scanning unit 10 is controlled by setting the reading period B of the line sensor 9 to the time when the light source extinguishing time B2 is incorporated. To do.

  In step S8, it is determined whether shooting has been completed up to the end of the document. If NO, the process returns to step S7 and scanning of the document is continued.

  In this way, the line sensor 9 is operated at a predetermined time interval while moving the light source unit 8 at a constant speed from the beginning to the end of the document, and the document is scanned and photographed to the end to scan the document.

  If YES in step S8, the process advances to step S9, the light source unit is turned off, and the process advances to step S10 to reversely rotate the motor 112 to return the light source unit 8 to the standby position. The rotation of the pulse motor 112 is stopped. In step S11, the series of controls is terminated.

  As described above, when the control unit 100 executes the reading scan of the document with the platen cover open, the reading cycle of the line sensor 9 is the same as that when the reading scan is executed with the plantain cover 3 closed. In order to obtain the same exposure amount with brightness, the time for turning off the light source 8 is set to a time, and the moving speed of the line sensor 9 during document scanning is controlled to control the scanning unit 10.

  Further, the control unit 100 sets the reading cycle of the line sensor 9 to an integral multiple of the pulse of the pulse motor 112, and changes the pulse width of the pulse motor 112, thereby reducing the moving speed of the light source unit 8 accordingly. .

  As described above, according to the image reading apparatus 1 according to the embodiment of the present invention, since the turn-off time B2 is added within the reading scanning period of one line of the line sensor, the reading scanning speed is slow, but the sky It eliminates the feeling of glare without reducing the amount of light on the shot.

  Further, since the brightness and exposure amount during one line reading scan by the line sensor 9 are not changed in the normal reading scanning performed with the platen cover closed, the shading data is obtained during the normal reading scanning and the sky shot. Can be shared.

  Further, when receiving a document reading command, it is determined whether the document reading scan with the platen cover 3 opened or the document reading scan with the plantain cover 3 closed, and a line sensor at the time of document reading scan If the moving speed of 9 is decreased accordingly, there is no need to perform a special mode setting switching operation prior to reading and scanning of the document, which is convenient.

  Furthermore, by increasing the pulse width of the pulse motor 112, the reading cycle of the line sensor 9 can be lengthened, and at the same time the movement speed of the light source unit 8 is decreased.

  The above-described embodiment is merely a preferred specific example of the present invention, and the present invention is not limited to the above-described embodiment.

  For example, the image reading apparatus 1 is not necessarily limited to an office multi-function machine that also serves as a scanner apparatus, a printer apparatus, and a copying apparatus. For example, the present invention can be applied to a facsimile multifunction machine, a scanner dedicated device, a copy dedicated device, and the like.

  Further, the platen cover state detection unit 7 is not necessarily limited to the one configured in the hinge 6 by an electric switch or the like that is conducted immediately before the platen cover 3 is closed. In the above embodiment, the platen cover state detection unit 7 for detecting the open / closed state of the platen cover 3 is provided. However, for example, a load detection unit for detecting a load applied to the flat bed 2 is provided to detect a load of a predetermined value or more. In this case, the document to be read may be regarded as a book document. Such a load detection part is realizable by arrangement | positioning of a piezoelectric element etc. between platen glass and a platen glass support part.

  Although not particularly related to the present invention, the platen cover 3 may be provided with an ADF (auto document feeder).

  Further, the control unit 100 may set the reading cycle of the line sensor 9 to any multiple of the pulse width of the pulse motor 112. Even in such a case, the moving speed of the light source unit 8 can be reduced accordingly by the change in the pulse width of the pulse motor 112.

  Further, the exposure amount within one reading cycle of the line sensor only needs to be constant, and various variations such as last, first, midway, and intermittent are possible for incorporation of the light extinction time B1 of the light source unit 8, for example. .

  In addition, it goes without saying that various design changes are possible within the scope of the claims of the present invention.

It is explanatory drawing which shows the structure of the image reading apparatus of embodiment of this invention. It is a block diagram which shows the structure of the control part of an image reading apparatus. It is a flowchart which shows the control point of the light source part of a control part. FIGS. 4A and 4B are explanatory diagrams for explaining a difference between normal reading and low-speed reading of the light source unit. FIG. 4A is a time chart for normal reading, and FIG. 4B is a time chart for low-speed reading. Indicates. HSYNC indicates the synchronization period of reading of the line sensor, Vled indicates a change in luminance, and M-Clk indicates a driving pulse of the pulse motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image reader 2 Flat bed 3 Platen cover 8 Light source part 9 Line sensor 10 Reading scanning part 100 Control part 112 Pulse motor
A, B Line sensor reading cycle
B1 OFF time
M-Clk pulse Vled brightness

Claims (3)

A flatbed for opening and closing the platen cover,
A reading scanning unit that performs scanning of the original by irradiating the original with light while moving the line sensor and the light source unit along the flat bed;
A control unit capable of controlling the light source unit and the reading scanning unit;
When performing scanning scanning of a document with the platen cover open, the control unit sets the scanning cycle of the line sensor to the same luminance and the same as when scanning scanning with the plantain cover closed. An image reading apparatus characterized in that the reading scanning unit is controlled by setting an extinguishing time of the light source so as to obtain an exposure amount. In claim 1,
When receiving the document reading command, the control unit determines whether the document reading scan with the platen cover opened or the document reading scan with the plantain cover closed, and at the time of the document reading scan, An image reading apparatus characterized in that the scanning speed is reduced accordingly. In claim 1 or 2,
The reading control unit includes a pulse motor that moves the light source unit,
The control unit sets the reading cycle of the line sensor to an integer multiple of the pulse of the pulse motor, and changes the pulse width of the pulse motor to reduce the moving speed of the light source unit accordingly. A characteristic image reading apparatus.

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