JP2010109982A - Image reading apparatus and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus and a method therefor wherein safety is improved by suppressing the temperature of slit glass from exceeding a fixed temperature by changing the quantity of illumination light and a reading speed in accordance with the number of images to be read per unit time. <P>SOLUTION: The image reading apparatus includes: a temperature sensor (23) for measuring a temperature at a predetermined position in the apparatus; a determination unit (51) for determining that the temperature measured by the temperature sensor reaches a reference temperature; a motor driver (33) for decelerating a reading speed of reading the information of a document at a fixed rate on the basis of a determination result of the determination unit; and a display unit (93) indicating that the reading speed of reading the information of the document is decelerated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and method for converting information contained in a reading object into an electrical signal.

  The reading device irradiates a reading object, that is, a document with light, guides reflected light from the document to a solid-state imaging device such as a CCD (Charge Coupled Device), and electrically reads an image of the document (reading object), An image signal is obtained. When the document is in a sheet form, an automatic document feeder (ADF) that automatically reads and replaces a plurality of documents can be used.

  The automatic document feeder takes out one document located on the paper feed tray [takes out], conveys it to a document reading position called a slit glass unit using a transport mechanism such as a roller [convey], and reads the document after reading. Finally, the paper is discharged to the paper discharge tray [discharge].

  The document transport device repeats the above-mentioned [Eject] to [Transport] to [Eject] until there is no document located on the paper feed tray.

  The reading device includes a light source that irradiates light on the document, at least one folding mirror that guides image light (scattered light) reflected from the document to the CCD, a lens that collects the image light, and the like in front of the CCD.

  The reading device further includes slit-shaped glass (hereinafter referred to as slit glass) that irradiates the original with light so that image light can be provided to the CCD, and the original that moves along the slit glass is supplied from the above-described light source. Illuminated with light to obtain reflected light (image light). The image light passes through a predetermined optical path defined by the above-described mirror, and is condensed on the CCD by the light condensing property provided by the above-described lens.

  Patent Document 1 (prior art document) discloses that in a sheet-through type image reading apparatus, a document of a specific type is detected and a document conveyance speed (conveyance motor speed) is changed.

  In the image reading apparatus disclosed in Patent Document 1, there is no description about the relationship between the number of documents and the reading speed. Further, there is no disclosure about the relationship between the number of documents and the temperature of the slit glass.

  However, when the reading speed is increased in order to improve the productivity of the reading apparatus, that is, to increase the reading speed, the amount of received light per unit time of the CCD decreases, leading to deterioration in the image quality of the read image. In order to solve this, there is a method of increasing the document irradiation light, that is, increasing the amount of irradiation light so that the amount of received light per unit time of the solid-state imaging device does not decrease.

  However, it is known that increasing the amount of irradiation light causes an increase in the temperature inside the apparatus, and the slit glass becomes hot particularly when reading a large amount of originals by the original conveying apparatus.

  The object of the present invention is to change the amount of light and the reading speed of the illumination light that illuminates the object according to the number of readings per unit time, and to prevent the temperature of the slit glass from exceeding a certain temperature, thereby increasing safety. It is an object to provide an improved image reading apparatus and method.

  The present invention has been made on the basis of the above problems, and is a temperature measuring means for measuring the temperature at a predetermined position inside the apparatus, and a judging means for determining that the temperature measured by the temperature measuring means has reached a reference temperature. And a speed control means for reducing the reading speed for reading the document information at a constant rate based on the determination result of the determination means, and the reading speed for reading the document information at a constant rate by the speed control means. It is an object of the present invention to provide an image reading apparatus characterized by having an informing means for informing the user of the fact.

  According to one embodiment of the present invention, when there is a risk that the slit glass becomes high in accordance with the reference temperature that has already been set, it is automatically switched to low-speed reading with reduced document irradiation light quantity. It becomes possible. In addition, the user is notified that the reading speed is switched to a low speed, that the reading speed is switched, or that the reading starts at a low speed.

  That is, based on the measured body temperature, the slit glass temperature is maintained so that the user does not feel “hot” even when the user accidentally touches when reading information on a continuous document by the sheet-through method. So (for example, reading time will increase) For example, "Isn't it a failure that glass is hot?" ] / "If you keep using it as it is, will it break down due to overheating?" It is possible to prevent the user from having unnecessary questions such as

  If the reading speed decreases during reading, “Are you sure it is not a malfunction? I can think of the question “ In addition, the user can recognize that the temperature of the slit glass is high (hot when touched), and it can be expected that the user will not touch the slit glass undesirably.

  Therefore, it is possible to obtain an image reading apparatus and method thereof that are highly safe and do not cause color misregistration, deterioration (fluctuation) in photoelectric conversion characteristics, or misalignment due to thermal deformation of the mounting portion.

1 is a schematic diagram illustrating an example of a configuration of an image reading apparatus to which the present invention is applied. FIG. 2 is a schematic diagram illustrating an example of control for setting a relationship between the number of reading sheets and a reading speed in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of control for guiding a reading condition (reading speed) at the start of reading in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of a display displayed on a display unit for notification to a user in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of a display displayed on a display unit for notification to a user in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of a display displayed on a display unit for notification to a user in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of a display displayed on a display unit for notification to a user in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating an example of a display displayed on a display unit for notification to a user in the image reading apparatus illustrated in FIG. 1.

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

  FIG. 1 shows an image reading apparatus to which the present invention is applicable.

  The image reading apparatus 1 shown in FIG. 1 conveys one sheet at a time to a reading position when an object to be read, that is, a document, is a sheet, discharges the document after reading, and supplies the next document to the reading position. An automatic document feeder (ADF) 101 is integrally provided. Note that the ADF 101 can also read when the object to be read is a three-dimensional object, a book, or the like, and can be used in an open state where the object is not in close contact with the table glass 5 of the image reading apparatus 1.

  The ADF 101 takes out a sheet-like document D set on the document tray 107 by a pickup roller 111 that is rotated by the driving force provided by the drive motor 103, and feeds a sheet roller 113 and transport rollers 117, 119, 121, 123, 125. , 127 and guided to the discharge tray 109. The document D is separated into one sheet by the second and subsequent sheets being pushed back to the document tray 107 side by a separation roller 115 that rotates in the reverse direction with respect to the paper feed roller 113. The rotation speed of the drive motor 103 is set by the motor driver 105. The ADF 101 has a function of inverting the front and back of the document D, but a detailed description thereof is omitted.

  The document D moves on the slit glass 3 of the image reading apparatus 1 between the transport rollers 121 and 123. The slit glass 3 is positioned so that the first (lamp) carriage 7 and the second (mirror) carriage 9 holding the xenon lamp 11 that illuminates the document D can acquire the reflected light from the document D that has passed through the slit glass 3 in advance. In this state, it is possible to read a document image called a sheet-through method. The transport roller 121 can correct the posture of the document D by temporarily stopping the leading end of the document D being transported (can remove the tilt that may occur when the document D is transported or taken out).

  The illumination light from the xenon lamp 11 continuously illuminates the document D moving on the slit glass 3. Reflected light from the document D (scattered light on the document), that is, image light in which images and characters held by the document D are converted into light brightness and darkness are transmitted by the first mirror 13, the second mirror 15, and the third mirror 17. The light is sequentially reflected and imaged on a solid-state imaging device (CCD, Charge Coupled Device) 21 by the condenser lens 19. The same applies to the case where the document D is positioned on the table glass 5. In this case, the xenon lamp 11 and the first mirror 13 are fixed along the table glass 5 by the first (lamp) carriage 7. It is well known to move at speed. In this case, the focus of the image light imaged on the CCD 21 can be maintained by moving the second carriage 9 at a speed half that of the first carriage 7. The moving speed of the first carriage 7 and the second carriage 9 is arbitrarily changed according to the number of input pulses supplied from the motor driver 33 to the drive motor 31 according to the reading magnification / resolution.

  The CCD 21 photoelectrically converts the received image light and outputs image data. The output image data is stored in the data memory 27. The image data held in the data memory 27 is subjected to processing such as contour correction by the image processing unit 71, and is connected to an external device such as an image forming device (printer) or an image display device (video playback) via the interface 81. Device) and the like.

  The above-described reading magnification / resolution defined when reading the image of the document D is input to the main control unit 51 via the operation panel 91.

  By the way, when reading the information of the document D by the sheet-through method, the xenon lamp 11 is continuously turned on and the same portion of the slit glass 3 is illuminated when the number of the documents D to be continuously read is large. The temperature of the slit glass 3 rises rapidly. In this case, if the user's finger or hand touches, the temperature may rise to a temperature at which the user feels hot, although there is no burn. For this reason, also from safety standards, there is a rule regarding the maximum temperature rise at an arbitrary position where a user represented by the slit glass 3 (or the table glass 5) can easily touch.

  From such a background, a temperature sensor 23 for detecting the temperature in the image reading apparatus 1 (hereinafter referred to as the internal temperature) is provided in the vicinity of the slit glass 3, and the internal temperature is numerically expressed by the temperature detection unit 25. When the in-body temperature reaches a certain level or higher by the control device 51, the reading speed is reduced at a constant rate, and the in-body temperature (slit glass temperature) is prevented from reaching a certain temperature. Note that a calculation program and various temperature data for reducing the reading speed from the temperature inside the machine are stored in a storage device (ROM, Read Only Memory) 53 in advance. In addition, the ROM 53 holds message data used to display a message necessary for notifying the user that the reading speed is reduced according to the temperature inside the apparatus in the display area 93 of the operation unit 91. Note that the message displayed in the display area 93 can be changed as appropriate by using a rewritable storage device such as a nonvolatile memory for the ROM 53. In addition, when a rewritable storage device is used, the degree to which the reading speed is reduced can be deflected at any time according to the characteristics of changes in the temperature inside the machine.

  For example, as shown in FIG. 2, when a predetermined number of documents D are placed on a sheet feed tray 107 of an ADF (automatic document feeder) 101 and a start button (not shown) on the operation panel 91 is pressed, the temperature sensor 23 Then, the temperature inside the machine is measured (act [1]).

  Next, temperature rise data is fetched from the RAM 53 (act [2]).

  Hereinafter, based on the captured temperature rise data, a “dangerous document read number”, which is the number of documents that can be read before reaching the upper limit temperature that the user feels hot when touched by the user's finger or hand, is calculated ( act [3]).

  For example, the upper limit temperature inside the machine (the upper limit temperature that the user feels hot when touched by the user's finger or hand is 50 ° C., the temperature increase coefficient a (for high-speed reading) is 0.05 ° C., and the temperature increase coefficient b (low speed Consider the case where (for reading) is set to 0.02 ° C./sheet.

  The temperature increase coefficient a for high-speed reading indicates the temperature in the apparatus (inside the apparatus) that rises when a single document is conveyed and read at a high-speed reading speed. That is, “0.05 ° C./sheet (temperature increase coefficient a)” means that the internal temperature of the apparatus increases by 1 ° C. when 20 originals are conveyed.

  The temperature increase coefficient b for low speed reading indicates the temperature in the apparatus (inside the apparatus) that rises when a single document is conveyed and read at a low speed reading speed. That is, “0.02 ° C./sheet (temperature increase coefficient b)” means that the internal temperature of the apparatus increases by 1 ° C. when 50 originals are conveyed.

  Here, a case where the temperature inside the machine is 47.5 ° C. is considered. The “dangerous document reading number”, which is the number of documents that can be read before reaching the upper limit temperature that the user feels hot when touched by the user's finger or hand, can be obtained as follows.

Aircraft dangerous temperature: 50 ℃
Aircraft temperature: 47.5 ° C
Temperature rise coefficient a: 0.05 ° C / sheet
Because
Allowable temperature up to the upper limit temperature in the aircraft
= Aircraft critical temperature-Aircraft temperature
= 50 ° C-47.5 ° C = 2.5 ° C.

Number of documents that can be transported up to the maximum temperature inside the machine
= Allowable temperature up to dangerous temperature inside the aircraft ÷ Temperature rise coefficient a
= 2.5 ℃ ÷ 0.05 ℃ / sheet
= 50 sheets.

  According to this calculation result, the first display (message) is displayed on the display unit 93 of the operation unit 91 from the main control unit 51 via the panel CPU 95 (act [4]).

The display contents will be described as [A] in FIG.
“If you scan 50 or more documents,
The reading glass may become hot.
In that case, switch to low-speed reading. ]
It is.

  The reason why the dangerous temperature inside the aircraft (upper temperature limit in the aircraft) is set to 50 ° C. is that when the user touches the slit glass 3 with his / her finger, he / she will not be burned, but “45 ° C. The upper limit of the temperature of the surface of the slit glass 3) ”is set as the temperature reached in about 10 minutes.

  Thereafter, the temperature inside the machine is measured again (act [5]).

  From the result, it is determined whether or not the temperature inside the machine is equal to or lower than the set critical temperature (act [6]).

  When the temperature is lower than the set critical temperature (act [6] -YES), the document irradiation light quantity (xenon lamp emission amount) is set for high speed reading (act [11]), and the reading speed is switched to high speed (act [12]). ).

  Hereinafter, based on the message data read from the ROM 53, the second display (message) is displayed on the display unit 93 of the operation unit 91 via the main control unit 51 and the panel CPU 95 (act [13]).

The display content will be described as [B] in FIG.
“The document is being scanned at high speed. ]
It is.

  Thereafter, the temperature inside the machine is measured again (act [14]), and from the result, it is determined whether or not the temperature inside the machine is below the set danger temperature (act [15]).

  When the temperature is lower than the set critical temperature (act [15] -YES), the high-speed reading process is executed as it is (act [16]).

  In the following, have all the originals been read by the empty sensor (not shown) of the paper feed tray 107? (Act [17]), and when all the documents held on the tray 107 run out, the entire reading operation is terminated (act [17] -YES).

  Of course, until the reading of all the originals is completed, the temperature inside the machine (act [14]), “the body temperature is a set critical temperature” judgment (act [15]), and the high-speed reading process (act [16]) ) Is repeated (act [17] -NO), and when “the in-body temperature reaches the set dangerous temperature” (act [15] -NO), the act [21] and later (low-speed reading) described below are performed. Executed.

  That is, the document irradiation light (the amount of light emitted from the xenon lamp) is reduced and set for low-speed reading (act [21]), and the reading speed is switched to low-speed reading (act [22]). Note that the low-speed reading is set to a reading speed that is half of the high-speed reading speed, as an example. At this time, a control signal is supplied from the main control unit 51 to the motor driver 105 on the ADF 101 side so as to reduce the rotation speed of the transport motor 103 to ½. At the same time, the main controller 51 changes the image reading speed (data transfer speed) by the CCD 21 in accordance with the reduced illumination light and reading speed.

  Thereafter, based on the message data read from the ROM 53, a third display (message) is displayed on the display unit 93 of the operation unit 91 via the main control unit 51 and the panel CPU 95 (act [23]).

The display content will be described as [C] in FIG.
“The temperature of the reading glass has increased.
The document is being scanned at a low speed. ]
It is.

  Thereafter, the temperature inside the aircraft is measured again (act [24]), and from the result, it is determined whether the temperature inside the aircraft is equal to or lower than the set dangerous temperature (act [25]).

  When the temperature is lower than the set critical temperature (act [25] -NO), the low-speed reading process is executed as it is (act [26]).

  In the following, have all the originals been read by the empty sensor (not shown) of the paper feed tray 107? Is determined (act [27]), and when the document held on the tray 107 runs out, the entire reading operation is terminated (act [27] -YES).

  Of course, until the reading of all the originals is completed, the temperature inside the machine (act [24]), the judgment “actual temperature inside the machine is a set critical temperature” (act [25]), and the low-speed reading process (act [26]). ) Is repeated (act [27] -NO), and when “the in-machine temperature is equal to or lower than the set critical temperature” (act [25] -YES), act [11] and subsequent (high-speed reading) are executed. .

  If the temperature inside the machine falls below the set temperature during the low-speed reading process (act [25] -YES), the process returns to the body temperature measurement (act [5]), and the high-speed reading process / low-speed reading process It may be determined which of the reading is performed (act [6]). Similarly, when the temperature inside the machine reaches the set temperature during the high-speed reading process (act [15] -NO), the process returns to the machine temperature measurement (act [5]) and the machine temperature is measured again. Then, it may be determined whether reading is performed by the high-speed reading process or the low-speed reading process (act [6]).

  Needless to say, in addition to displaying a visible message on the display unit 93 or independently, the user may be notified by voice.

  In this way, based on the measured body temperature, the slit glass temperature at which the user does not feel “hot” even when touching by mistake when reading information on a continuous document by the sheet-through method. By maintaining (reading time increases, for example) “Is the glass hot? ] / "If you keep using it as it is, will it break down due to overheating?" It is possible to prevent the user from having unnecessary questions such as

  If the reading speed decreases during reading, “Are you sure it is not a malfunction? I can think of the question “

  From such a background, an example is shown in FIG. 3, but when the user tries to start reading, that is, a predetermined number of documents D are placed on a sheet feed tray 107 of an ADF (automatic document feeder) 101, and the operation panel is displayed. When the start button 91 (not shown) is pressed, the temperature inside the machine is measured by the temperature sensor 23 (act [101]), the temperature rise data is fetched from the RAM 53 (act [102]), and the machine upper limit temperature ( It is determined whether or not the upper limit temperature that the user feels hot when touched by the user's finger or hand has been reached, that is, whether or not high-speed reading is possible (act [103]). It is also possible to display the possible reading speed on the display unit 93 of the operation panel 91 (act [104]).

As the display content, for example, at the timing (act [104]) shown as display [4] in FIG.
Shown as [D] in FIG.
“Scanning documents in high-speed mode is possible”, or
Shown as [E] in FIG.
“Scanning documents is possible in low-speed mode”
Is effective. For example, when “[E]” is displayed, the user can easily understand that the reading speed is approximately 20 sheets / minute. Also in this case, it goes without saying that the user may be notified by voice in addition to the display of the visible message on the display unit 93 or independently.

  In addition, the display or notification enables the user to recognize that the temperature of the slit glass 3 is high (hot when touched), and it can be expected that the user will not touch the slit glass undesirably.

  Note that the temperature rise of the CCD 21 is kept within a certain range by suppressing the intensity of light emitted from the xenon lamp 11 (the amount of emitted light) according to the body temperature so that the temperature inside the machine does not exceed a certain temperature. It is possible to prevent the occurrence of color misregistration due to the temperature rise of the CCD 21, the deterioration (fluctuation) of the photoelectric conversion characteristics, or the misregistration due to the thermal deformation of the mounting portion. In addition, a secondary effect of extending the life of the xenon lamp 11 can be expected.

  As described above, according to the present invention, when there is a risk that the slit glass becomes high in accordance with the reference temperature that has already been set, it is automatically switched to low-speed reading with a reduced amount of document irradiation light. It becomes possible. In addition, the user is notified that the reading speed is switched to a low speed, that the reading speed is switched, or that the reading starts at a low speed.

  That is, based on the measured body temperature, the slit glass temperature is maintained so that the user does not feel “hot” even when the user accidentally touches when reading information on a continuous document by the sheet-through method. So (for example, reading time will increase) For example, "Isn't it a failure that glass is hot?" ] / "If you keep using it as it is, will it break down due to overheating?" It is possible to prevent the user from having unnecessary questions such as

  If the reading speed decreases during reading, “Are you sure it is not a malfunction? I can think of the question “ In addition, the user can recognize that the temperature of the slit glass is high (hot when touched), and it can be expected that the user will not touch the slit glass undesirably.

  Therefore, it is possible to obtain an image reading apparatus which is highly safe and has no color misregistration, photoelectric conversion characteristic deterioration (fluctuation), or misalignment due to thermal deformation of the mounting portion.

  In addition, this invention is not limited to each embodiment mentioned above, A various deformation | transformation or change is possible in the range which does not deviate from the summary in the stage of the implementation. In addition, the embodiments may be implemented by appropriately combining them as much as possible, or by deleting a part thereof. In that case, various effects resulting from the combination or deletion can be obtained.

  DESCRIPTION OF SYMBOLS 1 ... Image reading device, 3 ... Slit glass, 5 ... Table glass, 7 ... 1st (lamp) carriage, 9 ... 2nd (mirror) carriage, 11 ... Xenon lamp, 13 ... 1st mirror, 15 ... 2nd mirror , 17 ... 3rd mirror, 19 ... Condensing lens, 21 ... CCD sensor (solid-state imaging device), 23 ... Slit glass temperature sensor, 25 ... Temperature detector, 27 ... Data memory, 31 ... Scan motor, 33 ... Motor driver 51 ... Main control unit, 53 ... ROM (memory table), 71 ... Image processing unit, 81 ... Interface, 91 ... Control panel, 93 ... Display unit, 95 ... Panel CPU, 101 ... Automatic document feeder (ADF), DESCRIPTION OF SYMBOLS 103 ... Conveyance motor, 105 ... Motor driver, 107 ... Document tray, 109 ... Discharge tray, 111 ... Pickup roller, 11 ... feeding roller, 115 ... separation roller, 117, 119 ... conveying roller, 121 ... registration rollers (conveying rollers), 123,125,127 ... conveying roller.

JP 2005-184497 A

Claims (5)

Temperature measuring means for measuring the temperature at a predetermined position inside the apparatus;
Determining means for determining that the temperature measured by the temperature measuring means has reached a reference temperature;
Based on the determination result of the determination means, a speed control means for reducing the reading speed for reading information on the document at a constant rate;
Informing means for informing that the reading speed for reading information on the document has been reduced at a constant rate by the speed control means;
An image reading apparatus comprising: Illumination means for outputting illumination light for illuminating information on the original;
Reading position providing means for irradiating the original with illumination light from the illumination means;
A light amount control unit that reduces the light amount of illumination light output from the illumination unit at a constant rate associated with the reading speed by the speed control unit when the reading speed is reduced by the speed control unit;
The image reading apparatus according to claim 1, further comprising:   The image reading apparatus according to claim 2, wherein the temperature measuring unit is located in the vicinity of the reading position providing unit. Measure the temperature near the document reading position,
When the measured temperature reaches the upper limit temperature allowed for the document reading position, the amount of illumination light that illuminates the document reading position and the reading speed for reading document information are reduced at a certain rate,
An image reading method for notifying that a document reading speed has been reduced.   5. The image reading according to claim 4, wherein when the temperature in the vicinity of the document reading position is lower than an upper limit temperature, the decrease in the constant ratio with respect to the light amount of the illumination light and the reading speed is cancelled. Method.

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