JP2024094801A - Image reading device and image forming apparatus - Google Patents

Abstract

To provide an image reading device and an image forming apparatus that can prevent false detection of opening and closing detection means.SOLUTION: An image reading device has a contact type image sensor 50 as an image reading unit, and a white reference board 38 as a reflecting member that is arranged opposite to the contact type image sensor 50 in a document reading area of the contact type image sensor 50. The image reading device includes a paper feed cover 33a as an opening and closing cover that holds the white reference board 38 and is openable and closable with respect to a device body. A controller as opening and closing detection means of the image reading device detects opening and closing of the paper feed cover 33a based on image data read based on reflected light from the white reference board 38. The angle of the white reference board 38 with respect to the paper feed cover 33a is changed in conjunction with the opening and closing of the paper feed cover 33a.SELECTED DRAWING: Figure 10

Description

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

Conventionally, an image reading device having the following configuration is known. That is, the image reading device has a light source that irradiates light onto a document, a light receiving unit that receives reflected light from the document, and reads a document image from the reflected light from the document received by the light receiving unit, a reflective member that is disposed opposite the image reading unit in the document reading area of the image reading unit and reflects the light from the light source, and an opening/closing cover that holds the reflective member and is configured to be openable and closable relative to the device body. The image reading device also includes an opening/closing detection means that irradiates light onto the reflective member from the light source and detects whether the opening/closing cover is open or closed based on the reflected light from the reflective member received by the light receiving unit.

Patent Document 1 describes an image reading device in which an image reading unit detects the opening and closing of an original pressing cover, which is an opening and closing cover that brings an original placed on the contact glass into close contact with the contact glass when closed. Specifically, a specular reflection unit is provided as a reflective member on the original pressing cover, and when detecting the opening and closing of the original pressing cover, light from the light source of the image reading unit is irradiated onto the specular reflection unit, and when the amount of light received by the light receiving unit of the image reading unit exceeds a reference light amount, it is recognized that the light receiving unit is receiving specularly reflected light that is specularly reflected from the specular reflection unit, and it is determined that the original pressing cover is in a closed state.

However, depending on the opening angle of the opening/closing cover, such as the document pressing cover, external light reflected by a reflecting member, such as a specular reflecting portion, may enter the light receiving portion of the image reading unit, causing the opening/closing detection means to erroneously detect that the opening/closing cover is closed.

In order to solve the above-mentioned problems, the present invention provides an image reading device that includes a light source that irradiates light onto a document, a light receiving unit that receives reflected light from the document, an image reading unit that reads a document image using the reflected light from the document received by the light receiving unit, a reflective member that is disposed opposite the image reading unit in the document reading area of the image reading unit and reflects the light from the light source, an opening/closing cover that holds the reflective member and is configured to be openable and closable relative to the device body, and an opening/closing detection means that irradiates light onto the reflective member using the light source and detects whether the opening/closing cover is open or closed based on the reflected light from the reflective member received by the light receiving unit, and is characterized in that the angle of the reflective member relative to the opening/closing cover is changed in conjunction with the opening and closing of the opening/closing cover.

The present invention makes it possible to prevent false detections by the open/close detection means.

FIG. 1 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. FIG. FIG. 2 is a schematic diagram of an ADF. FIG. 2 is a block diagram showing a main part of an electric circuit of the contact type image sensor. FIG. 11 is a control flow diagram for detecting whether the paper feed cover is open or closed. FIG. 11 is a control flow diagram for detecting whether a feed cover is open or closed while a document is being transported. FIG. 1 is a schematic diagram of the structure of a contact image sensor and its surroundings. FIG. 11A and 11B are diagrams for explaining a defect in a configuration in which a white reference plate is held by a paper feed cover so as not to be rotatable. 5A and 5B are diagrams for explaining the attitude of a white reference plate when a paper feed cover is opened in the embodiment. FIG. 13 is a diagram showing a modified example of the white reference plate.

The best mode for carrying out the present invention will be explained below with reference to the drawings. Note that a person skilled in the art can easily change or modify the present invention within the scope of the claims to create other embodiments, and these changes and modifications are included in the scope of the claims. The following explanation is an example of the best mode for the present invention, and does not limit the scope of the claims.

Hereinafter, an embodiment in which the present invention is applied to an image forming apparatus equipped with an image reading device will be described.
FIG. 1 is a perspective view showing an image forming apparatus 1 of the present embodiment.
The image forming apparatus 1 shown in FIG. 1 combines the functions of a copier, printer, facsimile machine, scanner, etc., and can record and output full-color images or monochrome images on recording paper or in a specified data format based on input data such as scanned image data.

Image forming device 1 is equipped with ADF 5, an automatic document feeder, above the paper feed unit, scanner unit 4, and image forming unit 15. Scanner unit 4 constitutes the image reading device main body, and together with ADF 5 constitutes image reading device 6.

The paper feed section of the image forming unit 15 includes, for example, multiple paper feed cassettes each storing cut-shaped recording paper, and multiple sets of paper feed rollers that pick up and feed recording paper from any of the paper feed cassettes. The paper feed section also has a paper feed path that includes various rollers that transport recording paper fed from any of the paper feed rollers to a predetermined image forming position in the image forming unit 15.

The image forming section 15 includes, for example, an exposure unit, multiple photosensitive drums, a developing device that uses toner of four colors, cyan (C), magenta (M), yellow (Y) and black (K), a transfer belt, a secondary transfer section and a fixing section.

The image forming unit 15 forms an electrostatic latent image on each photoconductor drum by exposing the photoconductor drum of each color with an exposure unit based on the read image read by the image reading device 6, and develops it by supplying toner to the latent image of each photoconductor drum with a development unit of each color of the development device. In addition, the image forming unit 15 primarily transfers the toner image on the photoconductor drum of each color to a transfer belt, and then superimposes it on the recording paper in a secondary transfer unit and performs secondary transfer, and then heats and pressurizes the toner image on the recording paper to fix it in the fixing unit, thereby forming a color image. Furthermore, the image forming unit 15 is capable of forming an external output image such as an image file or data that can be output to the outside based on the image read by the scanner unit 4 or a contact type image sensor 50 described later. Instead of the electrophotographic image forming unit 15 described above, an image forming unit using another recording method such as an inkjet method may be used.

Next, the image reading device 6 will be described.
FIG. 2 is a perspective view showing the scanner unit 4. As shown in FIG.
The scanner section 4 includes an integrated optical scanning unit (hereinafter referred to as "optical scanning unit") 40 as an image reading section in a housing 4a. The optical scanning unit 40 holds a light source and a contact type image sensor with the main scanning direction as the longitudinal direction (direction of arrow A), or holds a light source, a lens, a CCD (charge-coupled device) and a mirror. The optical scanning unit 40 is scanned (moved) in the sub-scanning direction (direction of arrow B) which is the scanning direction by a driving means provided in the scanner section 4, thereby reading a two-dimensional color image of a document placed on the contact glass 7. The contact glass 7 is provided on the upper part of the housing 4a of the scanner section 4 and constitutes the upper surface of the housing 4a. The driving means is composed of a wire fixed to the optical scanning unit 40, a plurality of driven pulleys and a driving pulley bridged by the wire, and a motor for rotating the driving pulley, and a publicly known one can be used.

In addition, a DF contact glass 71 is provided on the upper part of the housing 4a of the scanner unit 4 to allow the optical scanning unit 40 to read an image on a document sheet transported by the ADF 5. When reading an image on a document sheet transported by the ADF 5, the optical scanning unit 40 is positioned directly below the DF contact glass.

FIG. 3 is a schematic diagram of the ADF 5. As shown in FIG.
The ADF 5 is disposed above the scanner unit 4 and is attached to the scanner unit 4 by a hinge so that it can be opened and closed in either a closed position where it overlaps the scanner unit 4 or an open position where it stands up from the scanner unit 4.

The ADF 5 has an original placement tray 31 for placing the original before reading, a transport unit 33 as an original transport means for transporting the original, and an original stack tray 32 for stacking the original after reading.

The transport unit 33 has a separation feed section 34, a curved transport section 35, and a discharge section 36. The separation feed section 34 has a feed section 34a and a separation section 34b, and the feed section 34a feeds at least the topmost document of a stack of documents set therein, and the separation section 34b separates and feeds the documents MS one by one.

The curved transport section 35 has a transport drum 35a and pressure rollers 35b and 35c. The pressure rollers 35b and 35c bring the original into close contact with the transport drum 35a and turn the original upside down while folding it over.
The paper discharge section 36 includes a pair of paper discharge rollers 36 a and discharges the document from which the image has been read toward the document stack table 32 .

By placing the document on the document placement tray 31 and selecting scan on the operation panel 108 (see FIG. 4) (for example, pressing the copy start button), at least the topmost document is fed from the stack of documents placed on the document placement tray 31 by the paper feed unit 34a. The fed document is separated into a single sheet by the separation unit 34b and transported.

When the double-sided reading mode is set, the back side (second side) of the document is read by the contact image sensor (CIS) 50 arranged between the separation feed section 34 and the curved transport section 35. Specifically, the back side of the document being transported is sequentially partially facing the back contact glass 37 from the upstream portion in the transport direction and is read by the contact image sensor 50.

The document transported to the curved transport section 35 is in contact with the transport drum 35a by the pressure rollers 35b and 35c, and while being transported, the top and bottom are reversed and the transport direction is reversed. Then, the front side of the document, starting from the upstream part in the transport direction, faces the DF contact glass 71 of the scanner section 4 in sequence and is read by the optical scanning unit 40. After that, the document from which the document image has been read is discharged to the document stack table 32 by the pair of discharge rollers 36a.

A white reference plate 38 is disposed opposite the contact image sensor 50 across the document transport path, and serves as a reflective member for acquiring shading data from the contact image sensor 50.

The transport unit 33 of the ADF 5 has a paper feed cover 33a that can be opened and closed at the top, and the paper feed cover 33a covers the separation feed section 34, the curved transport section 35, and the paper discharge section 36.

The paper feed cover 33a holds the paper feed section 34a, one roller of the separation section 34b, the white reference plate 38, and the pressure roller 35b. By opening the paper feed cover 33a around the support shaft 133, the document transport path from the paper feed section 34a to the upstream side of the curved transport section 35 in the document transport direction is exposed, and any document jammed in this document transport path can be easily removed.

FIG. 4 is a block diagram showing the main parts of the electric circuit of the contact type image sensor 50. As shown in FIG.
The contact type image sensor 50 comprises a light source section 200 serving as a light source, a sensor chip 201 serving as a light receiving section, an image processing section 204, a frame memory 205, an output control circuit 206, and the like.

The light source unit 200 includes an LED array, a fluorescent lamp, a cold cathode fluorescent lamp, or the like. A plurality of sensor chips 201 are arranged in the main scanning direction (the direction corresponding to the document width direction). A plurality of OP amplifier circuits 202 are individually connected to each of the plurality of sensor chips 201. A plurality of A/D converters 203 are individually connected to each of the plurality of OP amplifier circuits 202.

The sensor chip 201 is equipped with a photoelectric conversion element and a condenser lens, which are called a 1:1 contact image sensor. Before the document enters the reading position by the contact image sensor 50, a lighting signal is sent to the light source unit 200 from the controller 100, which is a control unit that performs a series of controls for the ADF 5. This causes the light source unit 200 to light up and irradiate the light toward the back side of the document.

The light reflected by the back surface of the document is focused by a focusing lens onto the sensor chip 201 and read as image information. The image information read by each sensor chip 201 is amplified by an operational amplifier circuit 202, and then digitized and converted into image data by an A/D converter 203.

The image data obtained in this manner is input to the image processing unit 204, where shading correction and other processes are performed, and then temporarily stored in the frame memory 205. The image data is then converted by the output control circuit 206 into a data format acceptable to the main body control unit 111 (the control unit of the main body of the copier 1), and is then output to the main body control unit 111 via the interface circuit (hereinafter referred to as the I/F circuit 107).

The controller 100 outputs a timing signal to indicate when the leading edge of the document reaches the reading position of the contact image sensor 50, a lighting signal for the light source unit 200, power, etc. The timing signal to indicate when the leading edge of the document reaches the reading position is used to treat image data from that point onwards as valid data.

When the user selects either the double-sided or single-sided reading mode, places the document on the document tray 31, and presses the copy start button on the operation panel 108, a document feed signal is sent from the main body control unit 111 to the controller 100 via the I/F circuit 107. This starts the reading operation of the document placed on the document tray 31.

In this embodiment, the open/close state of the paper feed cover 33a is detected using a contact image sensor 50. This open/close detection of the paper feed cover 33a is performed at a predetermined interval, for example, every 20 seconds.

When the paper feed cover 33a is closed, the reference surface 38a of the white reference plate 38 faces the contact image sensor 50. At this time, the reflected light of the light source unit 200 that is reflected by the reference surface 38a of the white reference plate 38 is effectively incident on the sensor chip 201 of the contact image sensor 50, and the reference surface 38a is effectively read. Therefore, when the paper feed cover 33a is closed, the image data acquired by the contact image sensor is almost white and has a high image density.

When the paper feed cover 33a is opened, the white reference plate 38 held by the paper feed cover 33a moves away from the contact image sensor 50, and the reflected light of the light source unit 200 that reflects the reference surface 38a of the white reference plate and enters the sensor chip 201 decreases. As a result, the image density of the image data of the contact image sensor 50 decreases. Therefore, when the image density falls below the threshold value, it can be detected that the paper feed cover 33a is open.

FIG. 5 is a control flow diagram for detecting whether the paper feed cover 33a is open or closed.
5, the controller 100 transmits a turn-on signal to the contact image sensor 50, turns on the light source unit 200, reads an image, and acquires image data (S1, S2). The image data read by the contact image sensor 50 is sent to the controller 100 by the output control circuit 206. The controller 100 checks whether the image density of the sent image data is equal to or greater than a threshold value (S3). For example, the controller 100 calculates the average value of the image density of each pixel, and determines whether the average value is equal to or greater than the threshold value.

When the paper feed cover 33a is closed and the reference surface 38a of the white reference plate 38 faces the contact image sensor 50, the image density of the image data is equal to or greater than the threshold value as described above. Therefore, when the image density of the image data is equal to or greater than the threshold value (Yes in S3), it is determined that the paper feed cover 33a is closed (S4).

If the previous judgment result was "open" (Yes in S6), the controller 100 notifies the main body control unit 111 via the I/F circuit 107 that the paper feed cover 33a is closed. When the main body control unit 111 receives this notification from the controller 100, it ends the warning display on the display unit of the operation panel 108 indicating that the paper feed cover 33a is open. It also releases the prohibition on sending a document feed signal when the copy start button is pressed, allowing the document to be transported (S7).

On the other hand, when the paper feed cover 33a is open, as described above, the reflected light of the light source unit 200 that is reflected off the reference surface 38a of the white reference plate and incident on the sensor chip 201 of the contact image sensor 50 decreases, and the image density of the image data decreases. Therefore, when the image density of the image data is less than the threshold value (No in S3), it is determined that the paper feed cover 33a is open (S8).

When the controller 100 determines that the paper feed cover 33a is open, it checks whether the previous determination result was "closed" or not (S9). If the previous detection result was "closed" (Yes in S9), it notifies the main body control unit 111 via the I/F circuit 107 that the paper feed cover 33a is open. When the main body control unit 111 receives a notification from the controller 100 that the paper feed cover 33a is open, it displays a warning on the display unit of the operation panel 108 that the paper feed cover 33a is open. It also prohibits the sending of a document feed signal to the controller when the copy start button is pressed, and prohibits document transport (S10).

The threshold value may be changed based on the results of the previous detection of whether the paper feed cover 33a was open or closed. For example, if the previous detection of whether the paper feed cover 33a was open detects that the paper feed cover 33a was open, the threshold value is set to a value greater than the reference threshold value. This makes it possible to prevent erroneous detection that the paper feed cover 33a is closed when it is not completely closed.

On the other hand, if the previous open/close detection of the paper feed cover 33a detects that the paper feed cover 33a is closed, the reference threshold value is used. This makes it possible to prevent false detections caused by slight dirt on the reference surface 38a.

By using the contact image sensor 50 to detect whether the paper feed cover 33a is open or closed, there is no need to provide a separate means for detecting whether the paper feed cover 33a is open or closed, and the number of parts can be reduced. This allows the cost of the device to be reduced.

It is also possible to detect whether the paper feed cover 33a is open or closed based on image data acquired by the contact image sensor 50 without turning on the light source unit 200. In this case, when the paper feed cover 33a is opened, external light (light outside the device) is incident on the sensor chip 201 of the contact image sensor 50, and the image density of the image data acquired by the contact image sensor 50 increases. Therefore, when the image density becomes equal to or greater than a threshold value, it is possible to detect that the paper feed cover 33a has been opened.

However, when detecting whether the paper feed cover 33a is open or closed based on image data acquired by the contact image sensor 50 without turning on the light source unit 200, the following problem occurs. That is, when the environment in which the device is installed is dimly lit, the amount of external light incident on the sensor chip 201 of the contact image sensor 50 becomes insufficient, and even though the paper feed cover 33a is open, the image density falls below the threshold value, resulting in a problem in which the paper feed cover 33a is erroneously determined to be closed.

On the other hand, in this embodiment, by turning on the light source unit 200 and detecting whether the paper feed cover 33a is open or closed based on image data acquired by the contact image sensor 50, it is possible to detect whether the paper feed cover is open or closed even in a dimly lit environment where the device is installed.

In addition, in this embodiment, the contact image sensor 50 is used to detect whether the paper feed cover 33a is open or closed even while the document is being transported.

FIG. 6 is a control flow diagram for detecting whether the paper feed cover 33a is open or closed while a document is being transported.
Similarly to the above, when the timing for detecting whether the feed cover 33a is open or closed is reached, the controller 100 transmits a turn-on signal to the contact image sensor 50, turns on the light source unit 200, reads an image, and acquires image data (S11, S12). The image data read by the contact image sensor 50 is sent to the controller 100 by the output control circuit 206. Note that, when the timing for detecting whether the feed cover 33a is open or closed is reached, if the contact image sensor 50 is reading the back side of the document, the document read image data is transmitted to the controller 100.

The controller 100 extracts image data of the outer side of the document in the width direction from the image data sent based on the document width information detected by the document width size detection means that detects the width size of the document placed on the document placement table 31 (S13). The image data of the outer side of the document in the width direction is image data obtained by reading the reference surface 38a of the white reference board 38. Therefore, by using the image data of the outer side of the document in the width direction, it is possible to properly detect whether the paper feed cover 33a is open or closed.

If the image density of the extracted image data is less than the threshold value (No in S14), the controller 100 determines that the paper feed cover 33a has been opened and stops the transport of the document (S16). This makes it possible to prevent the document from being transported abnormally and to prevent damage to the document.

Furthermore, if it is determined that the feed cover 33a has been opened, the controller 100 notifies the main body control unit 111 via the I/F circuit 107 that the feed cover 33a has been opened during document transport. Based on the notification from the controller 100, the main body control unit 111 displays a warning message on the display unit of the operation panel 108 to inform the user that document transport has been stopped because the feed cover 33a was opened during transport, and to prompt the user to remove the document from the document transport path and set it again. In addition, the main body control unit 111 prohibits the transmission of a document feed signal to the controller 100 by pressing the copy start button (S18). The image forming operation also stops, and if there is paper in the paper transport path in the image forming device, instructs the user to remove the paper.

On the other hand, if the image density of the extracted image data is equal to or greater than the threshold value (Yes in S14) and it is determined that the feed cover is closed, the document continues to be transported.

In this embodiment, the threshold value is set to the image density when the opening angle of the paper feed cover 33a is 20°. If the threshold value is increased, it is possible to detect that the paper feed cover 33a is open when it is only slightly open (opening angle less than 20°). This is preferable because it allows the transport of the document to be stopped quickly while it is being transported and prevents damage to the document. However, if the threshold value is increased, there is a risk that slight dirt on the reference surface 38a may cause the paper feed cover 33a to be erroneously detected as open when in fact the paper feed cover 33a is closed.

By setting the threshold value to the image density when the paper feed cover 33a is opened at an angle of 20°, it is possible to suppress false detections and detect the opening of the paper feed cover 33a at an early stage when the paper feed cover 33a is opened.

FIG. 7 is a schematic diagram of the contact image sensor 50 and its surroundings, and FIG. 8 is a schematic perspective view of the white reference plate 38. As shown in FIG.
On both side surfaces of the white reference plate 38 perpendicular to the document width direction, there are provided a support hole 38d rotatably supported by the support shaft 62, and a guide hole 38b serving as an engagement portion with which the guide boss portion 61 serving as a boss portion engages. The guide hole 38b is an elongated hole having an arc shape centered on the center of the support shaft 62. With this configuration, the white reference plate 38 is held by the paper feed cover 33a so as to be rotatable within a predetermined range with the support shaft 62 as a fulcrum. The guide hole 38b may be an arc groove portion having the center at the center of the support shaft 62.

Spacer members 38c are provided on both ends of the reference surface 38a in the document width direction. The spacer members 38c come into contact with the rear contact glass 37, thereby ensuring a prescribed conveying gap between the white reference plate 38 and the rear contact glass 37.
The white reference plate 38 is biased toward the rear contact glass 37 by a plurality of pressure springs 39 (see FIG. 8) arranged at predetermined intervals in the document width direction. As a result, the white reference plate 38 is pressed against the rear contact glass 37 with a predetermined biasing force.

FIG. 9 is a diagram for explaining a problem with the configuration in which the white reference plate 38 is held by the paper feed cover 33a so as not to be rotatable.
In a configuration in which the white reference plate 38 is held by the paper feed cover 33a in a non-rotatable manner, when the paper feed cover 33a is opened, the reference surface 38a of the white reference plate 38 faces the opening side that is opened by opening the paper feed cover 33a. Therefore, as shown in FIG. 9, there is a risk that external light that enters the inside of the conveying unit from the opening side is specularly reflected by the reference surface 38a of the white reference plate 38 and enters the sensor chip 201 of the contact image sensor 50. The specularly reflected light is stronger than the diffusely reflected light, and the density of the image data becomes brighter without becoming darker even when the contact image sensor 50 and the white reference plate 38 are separated to a certain extent. As a result, there is a risk that the image density of the image data becomes equal to or higher than the threshold value (Yes in S14), and the paper feed cover 33a is erroneously detected as being closed even though it is open.

FIG. 10 is a diagram illustrating the position of the white reference plate 38 when the feeder cover 33a is open in this embodiment.
In this embodiment, when the paper feed cover 33a is opened, the white reference plate 38 rotates clockwise in the figure with the support shaft 62 as a fulcrum due to the biasing force of the pressure spring 39.
In this embodiment, since the support shaft 62 is located on the opposite side (left side in the figure) to the opening side that opens when the paper feed cover 33a is opened, the white reference plate 38 rotates in the opposite direction (clockwise in the figure) to the rotation direction (counterclockwise in the figure) when the paper feed cover 33a is opened. As a result, as shown in FIG. 10, the reference surface 38a of the white reference plate 38 faces the opposite side to the opening side, and external light entering from the opening side can be prevented from being incident on the reference surface 38a. This makes it possible to prevent external light reflected from the reference surface 38a from being incident on the sensor chip 201 of the contact image sensor 50. This makes it possible to effectively suppress erroneous detection of the paper feed cover 33a.

When the feed cover 33a is opened, the guide boss 61 hits the upper end of the guide hole 38b, restricting the clockwise rotation of the white reference plate 38 in the figure, and the white reference plate 38 is in the following position. That is, when the feed cover 33a is closed, the downstream end of the reference surface 38a of the white reference plate 38 in the document transport direction hits the rear contact glass 37. As a result, when the feed cover 33a is closed, the downstream end of the reference surface 38a of the white reference plate 38 in the document transport direction hits the rear contact glass 37 and rotates counterclockwise in the figure against the biasing force of the pressure spring 39, resulting in the state shown in FIG. 7.

FIG. 11 is a diagram showing a modified example of the white reference plate.
The white reference plate 138 of this modified example is configured when a contact type image sensor 50 with a shallow depth of field is used. When a contact type image sensor 50 with a shallow depth of field is used, the reference surface 38a cannot be read well in the configuration shown in Fig. 7, and there is a risk of the accuracy of shading correction decreasing. For this reason, the reference surface 38a is brought into contact with the rear contact glass 37.

The configuration in which the reference surface 38a contacts the rear contact glass 37 requires that the reference surface 38a be separated from the rear contact glass 37 against the biasing force of the pressure spring 39 so that the document can move between the white reference plate 138 and the rear contact glass 37. For this reason, the white reference plate 138 of this modified example is provided with an arm portion 138a that extends downstream in the transport direction of the document MS, and the pivot point of the white reference plate 138 is provided at a position downstream of the rear contact glass 37 in the document transport direction. In addition, an inclined plate 138b is provided that is inclined so as to move away from the document transport path from the upstream end of the reference surface 38a in the transport direction toward the upstream side in the document transport direction.

As shown in FIG. 11(a), when the leading edge of the document hits the inclined plate 138b, the conveying force of the document pushes the inclined plate 138b. Then, the white reference plate 138 rotates counterclockwise in the figure, with the support shaft 62 as a fulcrum, against the biasing force of the pressure spring 39, and the reference surface 38a moves away from the rear contact glass 37. As a result, as shown in FIG. 11(b), the document MS moves between the rear contact glass 37 and the white reference plate 138, pushing aside the white reference plate 138. When the trailing edge of the document MS comes out, the white reference plate 138 rotates clockwise in the figure due to the biasing force of the pressure spring 39, and the reference surface 38a comes into contact with the rear contact glass 37.

In this modified example, as in the embodiment, when the feed cover 33a is opened and the reference surface 38a is separated from the rear contact glass 37, the force of the pressure spring 39 rotates the feed cover 33a in the opposite direction (clockwise in the figure) to the rotation direction. This allows the reference surface 38a to face the opposite side of the opening when the feed cover 33a is opened (the rotation fulcrum side of the feed cover 33a), and external light that enters the device through the opening can be prevented from entering the reference surface 38a. This prevents external light reflected from the reference surface 38a from entering the sensor chip 201 of the contact image sensor 50. As a result, false detection of the feed cover 33a can be effectively suppressed.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and alterations are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description.

For example, the optical scanning unit 40 may be used to detect whether the ADF 5 is open or closed relative to the scanner unit 4. Specifically, the optical scanning unit 40 reads a white reference plate 41 for the scanner unit (see FIG. 3), which is a reflective member arranged opposite the DF contact glass 71, and detects whether the ADF 5 is open or closed based on the image density of the image data that is read.

The scanner white reference plate 41 is configured to rotate in the opposite direction to the rotation direction of the ADF 5 when the ADF 5 is opened. Specifically, the scanner white reference plate 41 is rotatably supported on the rotation fulcrum side (hinge side) of the ADF 5 by a support shaft, and the scanner white reference plate 41 is biased toward the DF contact glass 71 by a pressure spring.

As a result, when the ADF 5 is opened, the white reference plate 41 for the scanner unit rotates in the opposite direction to the rotation direction of the ADF 5, and the reference surface of the white reference plate 41 for the scanner unit can be oriented opposite to the opening side that opens when the ADF 5 is opened. This makes it possible to prevent external light entering from the opening side from being incident on the reference surface, and to prevent external light that is specularly reflected from the reference surface from being incident on the optical scanning unit 40. This makes it possible to effectively prevent erroneous detection of the opening and closing of the ADF 5.

The above description is merely an example, and each of the following aspects provides unique effects.
(Aspect 1)
In an image reading device having a light source such as a light source unit 200 that irradiates light onto a document, a light receiving unit such as a sensor chip 201 that receives reflected light from the document, an image reading unit such as a contact type image sensor 50 that reads a document image from the reflected light from the document received by the light receiving unit, a reflective member such as a white reference plate 38 arranged opposite the image reading unit in a document reading area of the image reading unit, an opening/closing cover such as a paper feed cover 33a that holds the reflective member and is configured to be openable and closable with respect to the device main body, and an opening/closing detection means such as a controller 100 that irradiates light onto the reflective member from the light source and detects whether the opening/closing cover is open or closed based on the reflected light from the reflective member received by the light receiving unit, the angle of the reflective member relative to the opening/closing cover is changed in conjunction with the opening and closing of the opening/closing cover.
According to this, it is possible to change the angle of the reflecting member relative to the opening of the opening/closing cover in conjunction with the opening of the opening/closing cover so that the external light entering through the opening opened by opening the opening cover is not reflected by the reflecting member and enters the light receiving unit. This makes it possible to suppress erroneous detection by the opening/closing detection means due to external light.

(Aspect 2)
In the first embodiment, a reflective member such as the white reference plate 38 is supported by an opening/closing cover so as to rotate in a direction opposite to the direction of rotation when an opening/closing cover such as the paper feed cover 33a is opened.
According to this, as described in the embodiment, when an opening/closing cover such as the paper feed cover 33a is opened, the opposing surface such as the reference surface 38a of the reflective member such as the white reference plate 38 that faces the image reading unit such as the contact type image sensor 50 can be made to face the opposite side to the opening side opened by opening the opening/closing cover. This makes it possible to prevent external light entering through the opening from being incident on the opposing surface. Therefore, external light reflected from the opposing surface is prevented from being incident on the light receiving unit such as the sensor chip 201 of the image reading unit, and erroneous detection by the opening/closing detection means due to external light can be prevented.

(Aspect 3)
In aspect 2, when viewed from the direction of the rotation axis of an opening/closing cover such as the paper feed cover 33a, the rotation fulcrum of a reflective member such as the white reference plate 38 is provided on the opening/closing cover rotation fulcrum side, and the reflective member is urged toward an image reading unit such as a contact-type image sensor 50 by a urging means such as a pressure spring 39.
According to this, as described in the embodiment, when an opening/closing cover such as the paper feed cover 33a is opened, the reflective member such as the white reference plate 38 can be rotated in the opposite direction to the rotation direction when the opening/closing cover is opened by the force of a biasing means such as the pressure spring 39.

(Aspect 4)
In aspect 3, a reflective member such as the white reference plate 38 has an engagement portion such as a guide hole 38b with which a boss portion such as a guide boss portion 61 provided on an opening/closing cover such as the paper feed cover 33a engages, and the engagement portion has an arc shape centered on the rotation center of the reflective member.
According to this, as described in the embodiment, a reflective member such as the white reference plate 38 can be held rotatably within a predetermined range with respect to an opening/closing cover such as the paper feed cover 33a.

(Aspect 5)
In any of aspects 1 to 4, an opening/closing detection means such as the controller 100 detects the opening/closing of an opening/closing cover such as the paper feed cover 33a based on the image density of the reflective member read image data read based on the reflected light of a reflective member such as the white reference plate 38 received by a light receiving unit such as the sensor chip 201.
According to this, as described in the embodiment, when an opening/closing cover such as the paper feed cover 33a is closed, light reflected from a reflective member such as the white reference plate 38 of a light source such as the light source unit 200 is smoothly incident on an image reading unit such as the contact image sensor 50, so that the reflective member read image data becomes brighter and the image density becomes higher. On the other hand, when the opening/closing cover is opened and the reflective member moves away from the image reading unit, the reflected light of the light source reflected from the reflective member that is incident on the image reading unit decreases, so that the reflective member read image data becomes darker and the image density becomes lower. Therefore, it is possible to detect whether the opening/closing cover is open or closed based on the image density of the reflective member read image data.

(Aspect 6)
In any of aspects 1 to 5, a document transport means such as a transport unit 33 for transporting a document is provided, and an image reading unit such as a contact type image sensor 50 reads a document image of the document being transported by the document transport means, and when an opening/closing detection means such as a controller 100 detects that the opening/closing cover has been opened while the document is being transported by the document transport means, the transport of the document is stopped.
According to this, as described in the embodiment, abnormal transport of the document can be prevented, and damage to the document can be prevented.

(Aspect 7)
In the sixth aspect, an opening/closing detection unit such as the controller 100 detects the opening/closing of an opening/closing cover such as the feed cover 33a based on read image data on the outer side in the width direction of the transported document while the document is being transported by the document transport unit.
According to this, as described in the embodiment, it is possible to detect whether a cover such as the feed cover 33a is open or closed even during transport of a document.

(Aspect 8)
The image forming apparatus includes an image reading device 6 that reads an image of an original document, and an image forming apparatus that forms an image on a recording material based on image data read by the image reading device 6. As the image reading device, any of the image reading devices according to aspects 1 to 7 is used.

1: Image forming device 4: Scanner unit 4a: Housing 5: ADF
6: Image reading device 7: Contact glass 15: Image forming section 31: Document placement table 32: Document stack table 33: Transport unit (document transport means)
33a: Paper feed cover (opening/closing cover)
34: Separation and feeding section 34a: Feeding section 34b: Separation section 35: Curved conveying section 35a: Conveying drum 35b: Pressing roller 35c: Pressing roller 36: Discharge section 36a: Discharge roller pair 37: Back contact glass 38: White reference plate (reflective member)
38a: Reference surface 38b: Guide hole (engagement portion)
38c: Spacer member 38d: Support hole 39: Pressure spring (biasing means)
40: Optical scanning unit 41: White reference plate for scanner section 50: Contact type image sensor (image reading section)
53: Document placement table 61: Guide boss portion (boss portion)
62: Support shaft 71: DF contact glass 100: Controller (open/close detection means)
200: Light source unit (light source)
201: Sensor chip (light receiving part)

Japanese Patent Application Laid-Open No. 10-32679

Claims (8)

A light source that irradiates light onto the original;
an image reading section that has a light receiving section that receives reflected light from the document and reads an image of the document using the reflected light from the document received by the light receiving section;
a reflecting member disposed opposite the image reading unit in a document reading area of the image reading unit and configured to reflect light from the light source;
an opening/closing cover configured to hold the reflective member and be openable/closable with respect to a device body;
an opening/closing detection unit that detects whether the opening/closing cover is open or closed based on light reflected from the reflecting member and received by the light receiving unit,
An image reading device, wherein an angle of the reflecting member with respect to the opening/closing cover is changed in conjunction with opening and closing of the opening/closing cover. 2. The image reading apparatus according to claim 1,
2. An image reading device according to claim 1, wherein the reflecting member is supported by the opening/closing cover so as to rotate in a direction opposite to a direction in which the opening/closing cover rotates when the opening/closing cover is opened. 3. The image reading apparatus according to claim 2,
When viewed from a rotation axis direction of the opening/closing cover, a pivot point of the reflection member is provided on a side of the opening/closing cover pivot point of the reflection member,
The image reading device according to claim 1, wherein the reflecting member is biased toward the image reading unit by a biasing means. 4. The image reading apparatus according to claim 3,
the reflecting member has an engagement portion with which a boss portion provided on the opening/closing cover is engaged,
The image reading device according to claim 1, wherein the engaging portion has an arc shape centered on the rotation center of the reflecting member. 2. The image reading apparatus according to claim 1,
The opening/closing detection means detects whether the opening/closing cover is open or closed based on image density of reflection member read image data read based on the reflected light of the reflection member received by the light receiving section. 2. The image reading apparatus according to claim 1,
a document transport means for transporting the document,
the image reading unit reads an original image of an original being transported by the original transport means,
When the open/close detection means detects that the open/close cover is opened while the original transport means is transporting the original, the transport of the original is stopped. 7. The image reading apparatus according to claim 6,
The image reading device according to claim 1, wherein the opening/closing detection means detects whether the opening/closing cover is open or closed based on read image data of an outer side of the transported document in a width direction when the document is transported by the document transport means. an image reading device for reading an image of a document;
an image forming apparatus for forming an image on a recording material based on image data read by the image reading device,
2. An image forming apparatus, comprising the image reading device according to claim 1 as said image reading device.

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