JP2012029193A - Document reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably detect the opening and closing operation of a document cover by a simple constitution.SOLUTION: With the opening and closing operation of an automatic document feeding part 10, the light quantity distribution of external light entering from an opening H is varied. According to the detection result of the variation in light quantity distribution, the opening and closing operation of the automatic document feeding part 10 is detected.

Description

  The present invention relates to a document reading apparatus.

  In general, a document reading device such as a scanner of a copying machine includes a platen glass on which a document to be read is placed, and a document cover for bringing the placed document into close contact with the platen glass.

  Various techniques for detecting the opening / closing operation of the document cover in the document reading apparatus have been conventionally proposed. For example, there is a technique described in Patent Document 1.

  In the technique described in Patent Document 1, a specular reflection unit is installed on a document cover, specular reflection light from the specular reflection unit is received by an image reading sensor, and an opening / closing operation of the document cover is detected based on the received light quantity. ing.

Japanese Patent Laid-Open No. 10-32679

  In Patent Document 1, a dedicated regular reflection portion is provided for detecting the opening / closing operation of the document cover in the document reading apparatus. For example, if a dedicated electrical component is provided for detecting the opening / closing operation of the document cover, With the provision of the dedicated electric parts, there is a risk that problems such as a complicated structure of the electric circuit and an increase in cost may occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a document reading apparatus that can reliably detect the opening / closing operation of a document cover with a simple configuration.

In order to achieve the above object, a document reading apparatus according to the present invention includes:
A platen glass on which the document is placed;
A document cover that is openable and closable above the platen glass, and closes the document to the platen glass in a closed state;
A light source for irradiating light on the document placed on the platen glass;
A reading unit that receives light reflected from the document and reads image information of the document;
A light amount changing unit that changes a light amount distribution of external light incident on the reading unit in accordance with the opening / closing operation of the document cover;
An open / close detection unit that detects a change in a light amount distribution of external light incident on the reading unit and detects an open / close operation of the document cover based on a detection result;
It is characterized by having.

  According to the document reading apparatus of the present invention, the opening / closing operation of the document cover can be reliably detected with a simple configuration.

1 is a central sectional view of an image forming apparatus. FIG. 3 is a central sectional view of the document reading device. 1 is a perspective view of a document reading device. 2 is a block diagram illustrating a control configuration of a document reading apparatus. FIG. FIG. 3 is a central sectional view of the document reading device. It is sectional drawing of the predetermined location which looked at a 1st mirror unit, the opening part, and the shielding member from the a direction of FIG. It is sectional drawing of the predetermined location which looked at a 1st mirror unit, the opening part, and the shielding member from the a direction of FIG. FIG. 10 is a flowchart illustrating an operation for detecting an opening / closing operation of an automatic document feeder and starting preparation for printing. It is a light quantity distribution figure of the main scanning direction read by a line reading part. It is the simple explanatory view which looked at the platen glass circumference from the upper part.

[Outline of image forming apparatus]
FIG. 1 is a central sectional view of the image forming apparatus X.

  The image forming apparatus X includes a document reading apparatus YS and an image forming apparatus main body GH. The image forming apparatus main body GH includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, a belt-shaped intermediate transfer belt 5, and the like.

  A document reading device YS including an automatic document feeder 10 and a reading unit 20 is disposed at the top of the image forming apparatus main body GH. The document D placed on the document table of the automatic document feeder 10 is transported by the transport unit, and an image on one or both sides of the document D is scanned and exposed by the optical system of the reading unit 20 and is read into the line reading unit.

  The signal formed by photoelectric conversion by the line reading unit is subjected to analog processing, A / D conversion, shading correction, image compression processing, and the like in the image processing unit, and then to the exposure units 3Y, 3M, 3C, and 3K. Sent.

  In the image forming unit 10Y that forms a yellow (Y) image, a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 7Y are arranged around the photosensitive drum 1Y. The image forming units 10M, 10C, and 10K have substantially the same configuration as the image forming unit 10Y. The developing units 4Y, 4M, 4C, and 4K include a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) toner having a small particle diameter and a carrier. The toner is composed of a pigment or dye serving as a color former, a wax that helps the toner peel from the fixing belt 81 after fixing, and a binder resin that holds these.

  The intermediate transfer belt 5 is wound around a plurality of rollers and is rotatably supported.

  The fixing unit 8 heats and presses the toner image on the paper P at a nip formed between the heated fixing belt 81 and the pressure roller 82 and fixes the toner image.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred to the rotating intermediate transfer belt 5 by the transfer units 6Y, 6M, 6C, and 6K, thereby forming a color toner image. . The paper P accommodated in the paper feed cassette CT is fed by the paper feed unit 91 and is conveyed to the transfer unit 6A through the paper feed rollers 92A, 92B, 92C, 92D, the registration rollers 93, and the like. A color toner image is transferred. The paper P on which the color toner image is transferred is heated and pressurized in the fixing unit 8, and the color toner image is fixed on the paper P. Thereafter, the sheet is sandwiched between the sheet discharge rollers 94 and placed on the sheet discharge tray 95.

  After the color toner image is transferred onto the paper P by the transfer unit 6A, the toner remaining on the intermediate transfer belt 5 from which the paper P has been peeled is removed by the cleaning unit 7A.

[Outline of document reader]
2 is a central sectional view of the document reading device YS, and FIG. 3 is a perspective view of the document reading device YS. As shown in FIGS. 2 and 3, the document reading device YS includes an automatic document feeder 10, a reading unit 20, and an operation unit 30. The automatic document feeder 10 automatically conveys the set document D to the reading unit 20. The reading unit 20 reads an image of a document placed on the platen glass 22.

  As shown in FIG. 3, the automatic document feeder 10 is attached to the reading unit 20 by a hinge unit 19 and can be opened and closed with respect to the reading unit 20. The automatic document feeder 10 covers the platen glass 22 and closes the document to the platen glass 22 in a closed state. That is, in the present embodiment, the automatic document feeder 10 has a function as a document cover.

  When one original is placed on the platen glass 22, the original is irradiated with light that is emitted from the light source 231 of the first mirror unit 23 and spreads in the main scanning direction (x direction in FIG. 3). The light source 231 includes a plurality of light emitting diodes installed in the main scanning direction. The light reflected from the document passes through the first mirror unit 23, the second mirror unit 24, and the imaging lens 25 and forms an image on the line reading unit (light receiving unit) 26.

  The line reading unit 26 reads an image of a document. The line reading unit 26 is composed of a line sensor in which a plurality of imaging elements that perform photoelectric conversion for each pixel are arranged in a one-dimensional manner in the main scanning direction, and reads an image of a document in units of one line in the main scanning direction.

  The first mirror unit 23 having the light source 231 moves in the sub-scanning direction (y direction) orthogonal to the main scanning direction, and the second mirror unit 24 has a moving speed that is ½ of the moving speed of the first mirror unit. Move in the same direction. Therefore, the reading surface can be moved in the sub-scanning direction by moving the first mirror unit 23 and the second mirror unit 24 in the sub-scanning direction with respect to the document on the platen glass 22. By sequentially moving the reading surface in the sub-scanning direction, the entire surface of the document can be scanned, and light reflected from the document can be sequentially read by the line reading unit 26 to read an image for one document.

  The automatic document feeder 10 feeds a plurality of documents D placed on a document placement table 11 one by one to a conveyance path by a separation roller 12, and a document conveyance unit 13 including a plurality of guide members and a plurality of rollers. It is conveyed and discharged onto the document discharge table 15. The image of the document D conveyed by the automatic document feeder 10 is read by the reading unit 20 at the document image reading position 21 in the conveyance path. That is, the reading surface can be moved in the sub-scanning direction by moving the document.

  When reading images on both sides of a document, the document D from which the image on the front surface is read is reversed by the document reversing unit 16 including a pair of rollers and a conveyance path switching guide, and is conveyed again to the document conveying unit 13. . The document from which the image on the back side is read is discharged to the document discharge table 15. As described above, in the document reading device YS, not only the document directly placed on the platen glass 22 but also the document conveyed by the automatic document feeder 10 can be read.

  As shown in FIG. 3, an operation unit 30 is installed on the front side of the reading unit 20, and the content of the reading operation in the document reading device YS can be set. The operation unit 30 has a touch panel format, and can display the status of the reading operation being executed by the document reading device YS.

  FIG. 4 is a block diagram showing a control configuration of the document reading apparatus YS, and shows only a typical control configuration.

  The control unit 100 controls the operation of each unit such as the storage unit 101 and the open / close detection unit 102 in the document reading apparatus YS.

  The control unit 100 is mainly configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., reads various control programs stored in the ROM, expands them in the RAM, To control the operation.

  The storage unit 101 stores various types of information in the document reading apparatus YS, and the information stored in the storage unit 101 is referred to when the control unit 100 controls the operation of each unit.

  The open / close detection unit 102 detects an open / close state and an open / close operation of the automatic document feeder 10, and the detection operation performed by the open / close detection unit 102 will be described later.

  The operations of the first mirror unit 23, the light source 231, the second mirror unit 24, and the line reading unit 26 are controlled by the control unit 100, and the reading operation is performed on the document or the like placed on the platen glass 22 as described above. Is called.

[Open / close state and open / close operation detection of automatic document feeder]
In the image forming apparatus X shown in FIG. 1, an operation of changing the automatic document feeder 10 from an open state to a closed state is detected in the document reading device YS. When the automatic document feeder 10 changes from the open state to the closed state, it is assumed that the document is placed on the platen glass 22 by the user, and the polygon mirrors (not shown) installed on the exposure units 3Y, 3M, 3C, 3K are considered. The first copy time is shortened by performing a print preparation operation such as starting rotation in the figure).

  First, a structure for detecting the open / close state and the open / close operation of the automatic document feeder 10 will be described with reference to FIGS.

  When the printing operation is stopped in the image forming apparatus X, the first mirror unit 23 is located at the home position shown in FIG.

  In the state shown in FIG. 5, an opening H (see FIG. 3) installed on the outer wall of the document reading device YS and a shielding member (light quantity changing unit) 27 are positioned above the first mirror unit 23. . The shielding member 27 moves to the front side and the back side in FIG. 5 in accordance with the opening / closing operation of the automatic document feeder 10.

  6 and 7 are cross-sectional views of predetermined portions of the opening H, the shielding member 27, and the first mirror unit 23 as viewed from the direction a in FIG. The position of the shielding member 27 in FIG. 6 is the position when the automatic document feeder 10 is closed, and the position of the shielding member 27 in FIG. 7 is the position when the automatic document feeder 10 is fully opened. Position.

  As shown in FIGS. 6 and 7, an opening H is provided in the outer wall YS1 of the document reading device YS. A shielding member 27 is installed below the opening H, and most of the external light R is shielded by the shielding member 27 and does not enter the first mirror unit 23. However, since the incident window 27A is installed in a part of the shielding member 27, a part of the external light R incident from the opening H passes through the incident window 27A and enters the first mirror unit 23, and the external light R is read by the line reading unit 26 (see FIG. 5 and the like).

  Although not shown in FIGS. 6 and 7, the shielding member 27 is mechanically connected to the automatic document feeder 10. When the automatic document feeder 10 is closed, the shielding member 27 is in the position shown in FIG. 6, but when the automatic document feeder 10 is opened, the shielding member 27 is interlocked with the opening operation of the automatic document feeder 10 in FIG. Move in the direction of arrow b. As a result, when the automatic document feeder 10 is fully open, the shielding member 27 is in the position shown in FIG.

  When the shielding member 27 moves in conjunction with the opening / closing operation of the automatic document feeder 10, the position of the incident window 27A installed on the shielding member 27 also moves, so that the position of the external light R incident on the first mirror unit 23 is changed. Change. As a result, the position of the external light R read by the line reading unit 26 also changes, and the light amount distribution in the main scanning direction in the line reading unit 26 changes. Based on the change in the light amount distribution, the open / close detection unit 102 detects the open / close state and the open / close operation of the automatic document feeder 10.

  Next, the operation of detecting the open / close state and the open / close operation of the automatic document feeder 10 using the structure of the document reading device YS shown in FIGS. 5 to 7 and starting the print preparation will be described in detail.

  FIG. 8 is a flowchart illustrating an operation for detecting the open / close state and the open / close operation of the automatic document feeder 10 and starting print preparation.

  First, in order to detect the open / close state and the open / close operation of the automatic document feeder 10, the line reading unit 26 performs an operation of reading outside light with the first mirror unit 23 set to the home position as shown in FIG. (Step S1).

  In step S1, the line reading unit 26 reads one line in the main scanning direction. However, since the external light R is incident on the line reading unit 26 at a position corresponding to the incident window 27A of the shielding member 27, The amount of light read by the line reading unit 26 is large. On the other hand, since the external light does not enter at other positions, the value of the light amount read by the line reading unit 26 is small. Accordingly, the light amount distribution in the main scanning direction read by the line reading unit 26 is as shown in FIG. 9, for example (in FIG. 9, the vertical axis indicates the light amount value of the line reading unit 26, and the horizontal axis indicates the main scanning direction. Position).

  Accordingly, in step S2, a position T (see FIG. 9) in the main scanning direction corresponding to an intermediate value between the maximum light amount value and the minimum light amount value among the values for one line read by the line reading unit 26 is specified. (One of the two positions T may be specified). The specified position T is representative of the light amount distribution in the main scanning direction read by the line reading unit 26, and changes as the shielding member 27 moves in conjunction with the opening / closing operation of the automatic document feeding unit 10. is there.

  In the storage unit 101 in the document reading device YS, the relationship between the position T in the main scanning direction corresponding to an intermediate value between the maximum light amount value and the minimum light amount value and the open / close position of the automatic document feeder 10 is stored as a data table. It is remembered. In step S3, the open / close position of the automatic document feeder 10 is determined based on the position T specified in step S2 with reference to the data table stored in the storage unit 101 (that is, represented by the position T). The open / close position of the automatic document feeder 10 is determined based on the change in the light amount distribution). The operation in step S3 is performed by the opening / closing detection unit 102 shown in FIG.

  If it is determined in step S3 that the automatic document feeder 10 is closed (step S3; Yes), the automatic document feeder 10 is stored in the storage unit 101 as “closed” (step S4).

  On the other hand, if it is determined that the automatic document feeder 10 is not closed (step S3; No), it is determined whether or not the automatic document feeder 10 is completely open (step S6). If it is determined that the document is fully open, the automatic document feeder 10 is saved as "open" in the storage unit 101 (step S7), and the operations of steps S1 to S3 are repeated. When the automatic document feeder 10 is halfway open (step S6; No), no history is stored in the storage unit 101, and the operations from step S1 to step S3 are repeated.

  If the automatic document feeder 10 is stored in the closed state in step S4, the open / close detector 102 refers to the history information stored in the storage unit 101, and the previous history is “the automatic document feeder 10 is opened. If it is, the automatic document feeder 10 is determined to have been changed from open to closed (step S5; Yes), and the document is placed on the platen glass 22, for example, the exposure units 3Y, 3M, A print preparation operation such as starting rotation of polygon mirrors installed at 3C and 3K is started (step S8). As a result, when the user presses the start button of the image forming apparatus X, since the polygon mirror is in a steady rotation, the printing operation can be started immediately and the first copy time can be shortened.

  As described above, the light amount distribution of the external light incident on the line reading unit 26 is changed using the shielding member 27 interlocked with the opening / closing operation of the automatic document feeder 10, and based on the detection result of the light amount distribution change. If the open / close state and the open / close operation of the automatic document feeder are detected, it is possible to clearly distinguish between the open state and the closed state of the automatic document feeder 10 with a simple configuration without providing a dedicated electric component. I can do it. As a result, for example, as shown in FIG. 8, the print preparation operation is started using the detection result of the opening / closing operation, and the first copy time can be shortened.

  In the operation of FIG. 8, the open / close state and the open / close operation of the automatic document feeder 10 are detected and printing preparation is started. However, the open / close state and open / close operation of the automatic document feeder 10 is detected, and the platen glass 22 is also opened. Printing preparation may be started by directly detecting that the original is placed. A structure for directly detecting that a document is placed on the platen glass 22 will be described with reference to FIG.

  FIG. 10 is a simple explanatory view of the periphery of the platen glass 22 as viewed from above.

  Below the platen glass 22, a light guide unit 28 that guides external light incident on the platen glass to the first mirror unit 23 and the line reading unit 26 is installed. If the document D is not placed on the platen glass 22, external light incident from the platen glass 22 is guided to the first mirror unit or the like by the light guide unit 28, but when the document D is placed on the platen glass 22, External light is blocked by the document D, and the external light is not guided to the first mirror unit by the light guide unit 28. Using this difference, it is directly detected that the document D is placed on the platen glass 22.

  In addition to the operation shown in FIG. 8, it is directly detected whether or not a document is placed on the platen glass 22, and when the automatic document feeder 10 is changed from open to closed, the document is placed on the platen glass 22. Even in such a case, the first copy time can be shortened by performing a print preparation operation such as starting rotation of polygon mirrors (not shown) installed in the exposure units 3Y, 3M, 3C, and 3K. I can do it.

  As described above, the present invention has been described with reference to FIGS. 1 to 10, but the present invention is not limited to the embodiment, and the present invention can be modified or added without departing from the gist of the present invention. included.

X image forming apparatus YS document reading apparatus 10 automatic document feeder 20 reading section 22 platen glass 26 line reading section 27 shielding member 27A incident window 28 light guide section H opening section 100 control section 101 storage section 102 open / close detection section 231 light source

Claims (3)

A platen glass on which the document is placed;
A document cover that is openable and closable above the platen glass, and closes the document to the platen glass in a closed state;
A light source for irradiating light on the document placed on the platen glass;
A reading unit that receives light reflected from the document and reads image information of the document;
A light amount changing unit that changes a light amount distribution of external light incident on the reading unit in accordance with the opening / closing operation of the document cover;
An open / close detection unit that detects a change in a light amount distribution of external light incident on the reading unit and detects an open / close operation of the document cover based on a detection result;
A document reading apparatus comprising:   The light quantity changing unit is configured to change a light quantity distribution of the external light incident on the reading unit by moving a position of an incident window through which the external light enters in accordance with the opening / closing operation of the document cover. The document reading device according to claim 1.   3. The document reading apparatus according to claim 1, further comprising a light guide unit that guides external light incident on the document placement position of the platen glass to the reading unit.

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