JP2011188204A - Image reading apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce light made incident on eyes of a user during original detection. <P>SOLUTION: An image reading apparatus includes an original platen; a light source which causes a plurality of LEDs (light emitting diodes) arranged side by side in a first direction to emit light toward an original placed on the original platen; and an original detector for emitting light from the light source in the original detection to detect a first direction size of the original from a width of reflection light from the original in the first direction. The original detector causes the light source to emit light from the plurality of LEDs discretely in the original detection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image reading apparatus and an image forming apparatus.

Currently, a light source such as a rare gas lamp or an LED is mounted on the image reading apparatus, and a document is read and a document is detected by light emission from the light source. The document detection means that the light source emits light toward the document when the document detection start switch is pressed by the document pressing cover, that is, when the user closes the document pressing cover after placing the document on the document table. This technology recognizes the document size from the reflected light. However, when the document pressing cover is not completely closed during document reading and document detection, the light of the light source enters the user's eyes, causing discomfort. For example, when a thick book or the like is read, the original presser cover cannot be closed more than usual, and light enters the user's eyes.
Therefore, as an invention for reducing light entering the eyes of the user, Patent Document 1 below discloses a scanner controller, an operation unit that accepts designation of a document size, a light source in which a plurality of LEDs are arranged in the main scanning direction, a CCD, The scanner controller includes an image reading device that emits light to the light source with a minimum width in the main scanning direction according to the designated document size when the operation unit accepts designation of the document size during document reading. It has been devised.

JP 2005-354205 A

  By the way, the invention of Patent Document 1 suppresses the light amount of the light source by performing light emission of the minimum necessary width in the main scanning direction according to the designated document size. This reduces the amount of light entering the user's eyes. However, Patent Document 1 is a technique for reducing light entering the user's eyes when reading a document, and is not a technique for reducing light entering the user's eyes during document detection.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to reduce light entering a user's eyes in document detection.

  In order to achieve the above object, according to the present invention, as a first solution means for an image reading apparatus, a document placing table and a first direction capable of emitting light toward a document placed on the document placing table. A light source composed of a plurality of LEDs (Light Emitting Diodes) arranged in a row, and a document detection for causing the light source to emit light in document detection and detecting a first direction size of the document from a width in a first direction of reflected light of the document In the image reading apparatus, the document detection unit employs a unit that discretely causes the plurality of LEDs to emit light to the document in the document detection.

  In the present invention, as the second solving means relating to the image reading apparatus, in the first solving means, the document detecting means is adapted to a first direction size of the smallest document size among readable standard documents. Further, a means is adopted in which the light source emits light with a light emission width in the first direction, and when the first direction size cannot be detected, the light emission width is increased stepwise in accordance with the standard document size.

  In the present invention, as the third solving means relating to the image reading apparatus, in the first or second solving means, the document detecting means is configured to use the first light source of the light source based on history information relating to the document size detected. A means of changing the light emission width in the direction is adopted.

  In the present invention, as a fourth solving means related to the image reading apparatus, in any one of the first to third solving means, the document detecting means is an LED (used for detecting a document among the plurality of LEDs). When the accumulated light emission time of the first LED exceeds a predetermined time, an unused LED (second LED) different from the first LED among the plurality of LEDs is used as the LED used in document detection. ), And then, when the accumulated light emission times of the second LED and the first LED become equal, the second LED is switched to the first LED.

  In the present invention, an image reading apparatus that employs any one of the first to fourth solving means is provided as a first solving means relating to the image forming apparatus, and an image of a document read by the image reading apparatus is included. A means for forming an image on the basis of this is employed.

  In the present invention, as the second solving means relating to the image forming apparatus, the first solving means includes a paper feed tray for containing the image forming paper, and the document detecting means is contained in the paper feeding tray. The light source emits light with a light emission width in the first direction that matches the size of the image forming paper in the first direction.

  According to the present invention, the document detection stage causes the plurality of LEDs to discretely emit light to the light source in document detection. As a result, the amount of light emitted during document detection is reduced, so that light entering the user's eyes can be reduced.

FIG. 3 is a functional block diagram of a multifunction peripheral A according to an embodiment of the present invention. FIG. 2 is a front view of an image reading unit 5 and a perspective view of a flat bed reading unit 30 of a multifunction peripheral A according to an embodiment of the present invention. It is a top view of the light source 32a of the multifunctional machine A which concerns on embodiment of this invention. 6 is a flowchart showing an operation of the multifunction peripheral A according to the embodiment of the present invention. It is a figure which shows the light emission pattern of the light source 32a of the multifunctional machine A which concerns on embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, the configuration of the multifunction peripheral A according to the present embodiment will be described with reference to FIGS.
The multifunction peripheral (image forming apparatus) A has a copy function, a print function, a scan function, and a facsimile transmission / reception function. As shown in FIG. 1, the multi-function device A includes a central processing unit (CPU) 1, a read only memory (ROM) 2, a random access memory (RAM) 3, various sensor groups 4, an image reading unit 5, and an image data storage unit. 6, a paper conveyance / image forming unit 7, a communication I / F unit 8, and an operation display unit 9 are provided.

The CPU 1 includes a control program stored in the ROM 2, various detection signals received from the various sensor groups 4, document image data, print image data and facsimile image data stored in the image data storage unit 6, and a communication I / F unit. The overall operation of the multi-function peripheral A is controlled based on various instructions input from the outside (client computer, public network, etc.) via 8 and operation instructions input from the operation display unit 9. The details of the control process of the CPU 1 will be described later as the operation of the multifunction device A.
The ROM 2 is a non-volatile memory that stores a control program executed by the CPU 1 and other data.

The RAM 3 is a volatile memory used as a working area as a temporary storage destination of data when the CPU 1 executes a control program and performs various operations.
The various sensor groups 4 are various sensors necessary for image forming operations such as a paper out detection sensor, a paper jam detection sensor, a temperature sensor, and a cover open / close detection sensor of a housing (not shown), and are detected by the respective sensors. The various information thus output is output to the CPU 1 as detection signals.

  As shown in FIG. 2A, the image reading unit 5 includes an ADF (Auto Document Feeder) 20 and a flat bed reading unit 30. An image of a document placed on the document or a document fed by the ADF 20 is read, and a document image signal based on the document image is output to the CPU 1. On the other hand, the CPU 1 creates document image data based on the document image signal input from the image reading unit 5 and stores the document image data in the image data storage unit 6.

  The ADF 20 includes a platen cover 21, a document placement tray 22, a pickup roller (not shown), a registration roller, a platen roller, and a discharge roller that are accommodated in the platen cover 21, and is placed on the document placement tray 22. A plurality of documents are automatically and sequentially fed one by one.

The platen cover 21 houses an automatic paper feeding mechanism such as a pickup roller, a registration roller, a platen roller, and a paper discharge roller, and is connected to the flat bed reading unit 30 by a hinge structure to open and close the flat bed reading unit 30. Is possible. Accordingly, the ADF 20 has a function as a document pressing cover for the document placed on the flat bed reading unit 30. In addition, ADF20 shown to (a) of FIG. 2 is a closed state.
The document placing tray 22 is a tray for placing a document to be read. A document placed on the document placement tray 22 is conveyed by a pickup roller, a registration roller, a platen roller, a paper discharge roller, and the like in the platen cover 21. Then, an image of the original is read by the flat bed reading unit 30 during the conveyance.

  As shown in FIGS. 2A and 2B, the flat bed reading unit 30 includes a platen glass 31, a full rate carriage 32, a half rate carriage 33, a carriage moving rail 34, a condensing lens 35, a CCD sensor 36, A reading unit housing 37 and a document pressing cover open / close detection sensor 38 are provided to read a document placed on the platen glass 31 by the user or a document automatically fed by the ADF 20. The CPU 1, the ROM 2, the RAM 3, the full rate carriage 32, the half rate carriage 33, the condensing lens 35, and the CCD sensor 36 constitute an original detection unit in the present embodiment.

The platen glass 31 is a glass plate that is fitted into the upper surface of the reading unit housing 37 and on which a document to be read is placed.
The full-rate carriage 32 extends under the platen glass 31 in the front-rear direction (main scanning direction) and is connected to a carriage moving rail 34 that extends in the left-right direction (sub-scanning direction). The full-rate carriage 32 includes a light source 32a that emits light toward an original on the platen glass 31 obliquely above, and a first mirror 32b that reflects reflected light of the original toward a half-rate carriage 33 described later. As shown in FIG. 3, the light source 32a has a plurality of LEDs (Light Emitting Diodes) arranged in the main scanning direction. Note that the dotted arrow shown in FIG. 2A indicates the path through which the light emitted from the light source 32 a reaches the CCD sensor 36.

  The full rate carriage 32 reciprocates along the carriage moving rail 34 in the left-right direction (sub-scanning direction) along the platen glass 31 when the user reads a document placed on the platen glass 31. The full rate carriage 32 is fixed below the left end of the platen glass 31 shown in FIG. 2A when reading a document fed by the ADF 20.

  Similar to the full-rate carriage 32, the half-rate carriage 33 is connected to a carriage moving rail 34 that extends in the front-rear direction (main scanning direction) below the platen glass 31 and extends in the left-right direction (sub-scanning direction). . The half-rate carriage 33 reflects the reflected light of the first mirror 32 b of the full-rate carriage 32 downward, and the third mirror 33 reflects the reflected light from the second mirror 33 a toward the condenser lens 35. And a mirror 33b.

The half-rate carriage 33 reciprocates along the carriage moving rail 34 in the left-right direction (sub-scanning direction) along the platen glass 31 when the user reads a document placed on the platen glass 31. At this time, the ratio between the moving speed of the full rate carriage 32 and the moving speed of the half rate carriage 33 is controlled to be 1: 0.5. Thereby, the optical path length of the reflected light until reaching the condenser lens 35 becomes constant. The half-rate carriage 33 is fixed at the position shown in FIG. 2A when reading a document fed by the ADF 20.
The carriage moving rail 34 is a moving rail for the full rate carriage 32 and the half rate carriage 33.

  The condensing lens 35 condenses the reflected light of the third mirror 33 b of the half rate carriage 33 and forms an image on the light receiving surface of the CCD sensor 36. The CCD sensor 36 operates in synchronization with the timing signal, photoelectrically converts the light received by the light receiving surface, and outputs a document image signal generated by the photoelectric conversion to the CPU 1. In the multi-function device A, the reflected light of the document is detected by the CCD sensor 36 during document detection, and the size of the document in the main scanning direction is detected based on the detection result of the CCD sensor 36. The size of the document in the sub-scanning direction is detected based on the detection result of a sub-scanning direction size detection sensor (not shown).

The reading unit housing 37 accommodates a full rate carriage 32, a half rate carriage 33, a carriage moving rail 34, a condensing lens 35, and a CCD sensor 36.
The document pressing cover open / close detection sensor 38 detects opening / closing of the ADF 20 having a function as a document pressing cover, and outputs the detection result to the CPU 1 as a detection signal.

The image data storage unit 6 is, for example, a flash memory or a hard disk, and stores document image data, print image data and facsimile image data received from the outside by the communication I / F unit 8 under the control command of the CPU 1.
The paper transport / image forming unit 7 includes a print engine (photosensitive drum, charger, developing device, fixing roller, and the like), a paper feed roller, a paper discharge roller, and the like. The paper transport / image forming unit 7 transports image forming paper from a paper feed tray (not shown) by a paper feed roller under a control command of the CPU 1, and an image (from toner) based on image data in the image data storage unit 6. The image forming sheet is transferred and fixed on the image forming sheet, and the image forming sheet is conveyed to a sheet discharge tray (not shown) by a sheet discharge roller.

The communication I / F unit 8 is connected to an external client computer and a public network, and transmits / receives various signals to / from the client computer and the public network.
The operation display unit 9 includes a copy function switching key, a print function switching key, a scan function switching key, a facsimile function switching key, a start key, a stop / clear key, a power key, a numeric keypad (numeric input key), a touch panel, and other various operations. Keys are provided, and each key operation instruction is output to the CPU 1 and various screens such as a copy preview image are displayed on the touch panel under the control of the CPU 1.

Next, the operation of the MFP A according to the present embodiment having the above-described configuration will be described in detail with reference to FIG.
First, a user who wants to copy in the multifunction device A places a document on the platen glass 31 and closes the ADF 20.

  The CPU 1 determines whether or not the ADF 20 is closed after being opened based on the detection signal of the document pressing cover open / close detection sensor 38 (step S1). If the CPU 1 determines “NO” in step 1, that is, if it is not closed after the ADF 20 is opened, the CPU 1 waits until it is closed after the ADF 20 is opened. When the CPU 1 determines “YES” in step 1, that is, when the ADF 20 is closed after being opened, the CPU 1 considers that the document is placed on the platen glass 31 and the plurality of LEDs of the full rate carriage 32. Are discretely emitted to the light source 32a (step S2).

  The operation in step S2 will be specifically described with reference to FIG. In FIG. 5, the LED of the light source 32a surrounded by a circle indicates an LED that emits light. The CPU 1 may cause every other LED of the light source 32a to emit light as shown in FIG. Further, as shown in FIG. 5B, the CPU 1 may cause two LEDs of the light source 32a to emit light every two.

  After step S2, the CPU 1 detects the size of the document in the main scanning direction from the width of the reflected light of the document in the main scanning direction based on the detection result of the CCD sensor 36 (step S3). When step S3 ends, the CPU 1 detects the size of the document in the sub-scanning direction based on the detection result of the sub-scanning direction detection sensor, and determines the document size based on the size of the document in the main scanning direction and the size of the sub-scanning direction ( Step S4).

  As described above, in the multi-function device A, the CPU 1 causes the light source 32a to emit a plurality of LEDs discretely in document detection. As a result, the amount of light emitted during document detection is reduced, so that light entering the user's eyes can be reduced.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the above embodiment, the light emission width of the light source 32a in the main scanning direction (the length from the LED that emits light at one end to the LED that emits light at the other end) is not changed. It is not limited.
For example, the CPU 1 causes the light source 32a to emit light with a light emission width that matches the main scanning direction size of the minimum document size that can be read by the multifunction peripheral A in the standard document. When the main scanning direction size of the original cannot be detected because the main scanning direction size of the original is longer than the light emission width of the light source 32a, the CPU 1 adjusts to the main scanning direction size of the next largest original size. The light source 32a emits light with the light emission width. In this way, the main scanning direction size of the document may be detected while gradually increasing the light emission width of the light source 32a. Specifically, when the minimum readable document size in the MFP A is B5 size, the light emission width of the light source 32a is increased in the order of B5 size, A4 size, B4 size, and A3 size.

When the same user is copying continuously, the CPU 1 stores the document size detected by the immediately preceding document detection in the ROM 2 as history information. Then, the CPU 1 causes the light source 32a to emit light with a light emission width that matches the size of the document size detected in the immediately preceding document detection based on the history information.
Further, the CPU 1 may cause the light source to emit light with a light emission width that matches the size of the image forming paper stored in the paper feed tray in the main scanning direction.

(2) In the above embodiment, the LEDs are discretely emitted in step S2. However, the LEDs used in document detection need not be fixed. For example, when the accumulated light emission time of the LED (first LED) used in the document detection exceeds a predetermined time, the CPU 1 stops using the first LED in the document detection, and the plurality of LEDs of the light source 32a are stopped. An unused LED (second LED) different from the first 1ED is used for document detection. The CPU 1 stops use of the second LED in document detection and uses the first LED again when the time further elapses and the cumulative emission times of the second LED and the first LED become equal. To do. That is, when the LED surrounded by a circle in FIG. 5 is used for document detection and the accumulated emission time of the LED exceeds a predetermined time, the LED used for document detection is surrounded by a circle. It switches to the LED that is not. Thereafter, when the accumulated light emission times of the LED and the LED surrounded by the circle become equal, the LED used for document detection is switched to the LED surrounded by the circle.

  For example, when an LED having a lifetime of 3000 hours is used, when the cumulative emission time of the first LED reaches 300 hours, the LED used for document detection is switched to the second LED, and the second LED If the cumulative emission time of the LED reaches 300 hours, a control of switching to the first LED can be considered. Thus, by switching the LEDs used in the document detection, it is possible to prevent the performance of the image reading function from being lowered due to the deterioration of the specific LEDs. In general, an LED is said to have a lifetime up to 70% of the initial light amount.

  A ... MFP (image forming apparatus), 1 ... CPU, 2 ... ROM, 3 ... RAM, 4 ... various sensor groups, 5 ... image reading unit, 6 ... image data storage unit, 7 ... paper transport / image forming unit, DESCRIPTION OF SYMBOLS 8 ... Communication I / F part, 9 ... Operation display part, 20 ... ADF, 21 ... Platen cover, 22 ... Document loading tray, 30 ... Flat bed reading part, 31 ... Platen glass, 32 ... Full-rate carriage, 32a ... Light source 32b ... first mirror 33 ... half rate carriage 33a ... second mirror 33b ... third mirror 34 ... carriage moving rail 35 ... condensing lens 36 ... CCD sensor 37 ... reader casing 38. Document holding cover open / close detection sensor

Claims (6)

A light source composed of a document placing table, a plurality of LEDs (Light Emitting Diodes) arranged in a first direction capable of emitting light toward the document placed on the document placing table, and causing the light source to emit light in document detection. An image reading apparatus comprising: a document detection unit configured to detect a first direction size of the document from a width in a first direction of reflected light of the document;
The image reading apparatus, wherein the document detecting unit causes the plurality of LEDs to emit light to the light source discretely in the document detection.   The original detection means causes the light source to emit light with a light emission width in a first direction corresponding to a first direction size of a minimum original size among readable standard originals, and cannot detect the first direction size. The image reading apparatus according to claim 1, wherein the light emission width is increased in a stepwise manner in accordance with a standard document size.   The image reading apparatus according to claim 1, wherein the document detection unit changes a light emission width of the light source in a first direction based on history information regarding a document size detected by the document.   The document detection means, when the accumulated light emission time of the LED (first LED) used for document detection among the plurality of LEDs exceeds a predetermined time, the LED used for document detection is replaced with the plurality of LEDs. When the LED is switched to an unused LED (second LED) different from the first LED, and then the accumulated light emission times of the second LED and the first LED become equal, the second LED The image reading apparatus according to claim 1, wherein the LED is switched from the first LED to the first LED.   An image forming apparatus comprising the image reading apparatus according to claim 1, wherein the image forming apparatus forms an image based on an image of a document read by the image reading apparatus. A paper feed tray for storing image forming paper;
6. The light source according to claim 5, wherein the document detection unit causes the light source to emit light with a light emission width in a first direction that matches a size in a first direction of an image forming sheet accommodated in a paper feed tray. Image forming apparatus.

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