JP7443828B2 - Image reading device and image forming device - Google Patents

Description

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

Conventionally, as a technique related to an image reading device, the technique disclosed in, for example, Patent Document 1 has already been proposed.

Patent Document 1 discloses a mounting table glass on which a sheet is placed, a sheet pressing section that can be opened and closed to press the sheet placed on the mounting table glass from above, and a state in which the sheet is pressed from above by the sheet pressing section. An image reading section that reads an image of the seat; an electric opening/closing section that assists in manual opening/closing of the sheet pressing section; and a sheet pressing section using the electric opening/closing section according to an external force applied to the sheet pressing section when manually opening/closing the sheet pressing section. a speed changing section that changes the opening/closing speed of the seat pressing section; an opening/closing angle detection section that detects the opening/closing angle of the seat pressing section; and a seat pressing section changing the opening/closing speed according to external force based on the detection signal from the opening/closing angle detection section. If the sheet pressing part is in the first area, it is determined whether the sheet pressing part is in the first area, the second area just before the sheet pressing part is fully closed, or the third area just before the sheet pressing part is fully opened. An opening/closing speed setting that changes the opening/closing speed according to an external force when it is determined, and sets the opening/closing speed to a preset opening/closing speed regardless of the external force when it is determined that the seat pressing part has moved to the second area or the third area. The device is configured to include a section and a section.

Japanese Patent Application Publication No. 2008-191197

SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading device and an image reading device capable of reducing the operating force required to open a document conveying means without impairing operability, compared to a case where the document conveying means is driven to open and close over the entire opening/closing angle of the document conveying means. An object of the present invention is to provide an image forming apparatus.

The invention described in claim 1 includes a document holding means that is attached to the main body of the apparatus so as to be openable and closable via a rotating shaft, and presses the document;
a pulling force applying means for temporarily applying a driving force of a drive source to the document pressing means as a pulling force to pull up the document pressing means in the direction of opening the document pressing means when the document pressing means is opened;
Equipped with
The pulling force acting means includes a pulling force acting member rotatably disposed inside the document pressing means with the rotating shaft as a fulcrum;
The image reading device includes a wire member that applies a pulling force in a direction to open the document holding means to an end of the pulling force applying member located on the opposite side to the rotation axis.

According to a second aspect of the invention, the pulling force applying member has an acting arm that branches from an intermediate position along the longitudinal direction and applies a pulling force in an opening direction to the document holding means. The image reading device according to item 1.

According to a third aspect of the invention, the pulling force applying means converts the moving direction of the wire member into the opening/closing direction of the document holding means via a pulley disposed in the middle of the wire member. 2. The image reading device according to item 2.

The invention described in claim 4 is an image reading device according to claim 1, further comprising an absorbing means that absorbs an excessive force that exceeds a predetermined value when an excessive force exceeding a predetermined value is applied to the pulling force applying means. It is a device.

The invention set forth in claim 5 is the invention set forth in claim 4, wherein the absorbing means comprises an elastic member that absorbs the excessive force by elastically deforming when the excessive force acts on the pulling force applying means. This is the image reading device described.

The invention described in claim 6 includes an image reading means for reading an image of the document conveyed to a reading position by the document pressing means,
The image reading device according to claim 1, wherein the drive source is a drive source for the image reading means.

A seventh aspect of the present invention is the image reading apparatus according to the sixth aspect, wherein power to the drive source is cut off when the document holding means is open .

The invention described in claim 8 includes an image reading means for reading an image of the document;
image forming means for forming an image of the document read by the image reading means;
Equipped with
An image forming apparatus using the image reading device according to any one of claims 1 to 7 as the image reading means.

According to the invention described in claim 1, compared to the case where the opening/closing drive is performed over the entire opening/closing angle of the document conveying means, it is possible to reduce the operating force when opening the document conveying means without impairing operability. A possible image reading device can be provided.

Further, according to the invention described in claim 1, the pulling force acting means includes a pulling force acting member rotatably disposed inside the document holding means so as to be rotatable about a rotating shaft, and a pulling force acting member. The configuration can be simplified compared to a case in which there is no wire member that applies a pulling force in the direction of opening the document holding means to the end located on the opposite side of the rotation axis.

According to the invention set forth in claim 2, the pulling force acting member does not have a working arm that branches from an intermediate position along the longitudinal direction and applies a pulling force in the opening direction to the document holding means. In this case, a larger pulling force can be applied to the document holding means than in the case where the document is held down.

According to the invention described in claim 3, the pulling force applying means applies a pulling force by the wire member, compared to a case where the pulling force applying means does not include a pulley that converts the moving direction of the wire member to the opening/closing direction of the document holding means. You can freely set the position.

According to the invention set forth in claim 4, malfunctions when excessive force is applied to the opening force acting means can be avoided, compared to the case where no absorbing means for absorbing excessive force is provided.

According to the invention set forth in claim 5, the structure of the opening force applying means can be simplified compared to the case where the absorbing means is not composed of an elastic member.

According to the invention described in claim 6, the number of parts can be reduced compared to the case where the drive source of the image reading means is not used as the drive source.

According to the seventh aspect of the present invention, the possibility that the document conveying means malfunctions when the document conveying means is opened can be avoided compared to a case where the power supply is not cut off when the document conveying means is opened and closed.

According to the invention described in claim 8, when opening the document conveying means without impairing operability, compared to the case where the image reading device according to any one of claims 1 to 7 is not used as the image reading means. It is possible to provide an image forming apparatus that can reduce operating force.

1 is an overall configuration diagram showing an image forming apparatus to which an image reading apparatus according to Embodiment 1 of the present invention is applied; FIG. 1 is a configuration diagram showing an image reading device according to Embodiment 1 of the present invention. FIG. 1 is a configuration diagram showing an automatic document feeder according to Embodiment 1 of the present invention. FIG. 1 is a perspective configuration diagram showing an open state of the automatic document feeder of the image forming apparatus according to Embodiment 1 of the present invention; FIG. 1 is a configuration diagram showing an automatic document feeder according to Embodiment 1 of the present invention. FIG. There is a graph showing the rotational moment required to open the automatic document feeder according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram showing a reed switch. 1 is a configuration diagram showing a closed state of the automatic document feeder according to Embodiment 1 of the present invention. FIG. 1 is a configuration diagram showing main parts of an automatic document feeder according to Embodiment 1 of the present invention. FIG. FIG. 2 is a plan configuration diagram showing a push-up device. 1 is a configuration diagram showing main parts of an automatic document feeder according to Embodiment 1 of the present invention. FIG. FIG. 2 is a plan configuration diagram showing a push-up device. FIG. 2 is a block diagram showing a control device. 1 is a configuration diagram showing main parts of an automatic document feeder according to Embodiment 1 of the present invention. FIG.

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

[Embodiment 1]
FIG. 1 is a block diagram showing an overall outline of an image forming apparatus to which an image reading apparatus according to Embodiment 1 of the present invention is applied.

<Overall configuration of image forming apparatus>
The image forming apparatus 1 according to the first embodiment is configured as a color copying machine that forms color images using a so-called inkjet method, for example. The image forming device 1 includes an image reading device 3 serving as an example of an image reading device that reads an image on a document 6, and an image forming device forming an image on a recording medium based on image data read by the image reading device 3. An image forming section 2 is provided as an example. The image reading device 3 is disposed above the device main body 1a that houses the image forming section 2 and is supported by a support section 4. A space is formed between the image reading device 3 and the device main body 1a for ejecting a recording medium on which an image is formed.

As shown in FIG. 1, the image reading device 3 includes a control panel 66, which serves as an operation unit for operating the image forming device 1 and the image reading device 3, on the upper part of the front wall 311 located at the front of the casing 31. is provided. The control panel 66 has a touch panel 67 that also serves as a display section for displaying operation menus, warnings, messages, etc. to the operator (user), and accepts various settings for the displayed operation menu, and a plurality of operation buttons 68. .

The image forming unit 2 accommodates a plurality of inkjet heads 10 that eject ink onto a recording medium to form an image, and a required recording paper 5 as an example of a recording medium to be supplied to the image forming position of each inkjet head 10. The recording paper 5 includes a paper feeding device 50 that transports the recording paper 5, and a transporting device 40 that transports the recording paper 5 supplied from the paper feeding device 50 to an image forming position and then discharges it. The device main body 1a is formed of a support structure member, an exterior cover, and the like. Note that in the figure, a broken line indicates a conveyance path along which the recording paper 5 is conveyed inside the apparatus main body 1a of the image forming apparatus 1.

The inkjet head 10 includes inkjet heads 10Y, 10M, 10C, and 10K that respectively correspond to inks of yellow (Y), magenta (M), cyan (C), and black (K). The inkjet heads 10Y, 10M, 10C, and 10K of each color are arranged in order in the conveyance direction of the recording paper 5. Each inkjet head 10 forms an image on the recording paper 5 by ejecting ink droplets under the control of the control device 100 .

The inkjet head 10 is formed with a plurality of ink ejection ports (not shown) arranged in a width direction that is a direction intersecting the conveying direction of the recording paper 5 . Then, each inkjet head 10 ejects ink droplets from the ink ejection opening onto the recording paper 5 that is supplied from the paper feeding device 50 and transported by the transport device 40 in accordance with the image information. Note that the method of ejecting ink droplets by the inkjet head 10 is not particularly limited, and for example, a thermal method that ejects ink droplets using heat, or a method that uses a piezoelectric element or the like to eject ink droplets using pressure. A piezoelectric method for discharging or the like can be adopted as appropriate.

Each inkjet head 10 is supplied with ink of a corresponding color from an ink cartridge 30. The ink cartridge 30 includes ink cartridges 30Y, 30M, 30C, and 30K that respectively correspond to yellow (Y), magenta (M), cyan (C), and black (K) color inks. Each ink cartridge 30 stores ink of each color. Specifically, the ink cartridge 30Y stores yellow ink, the ink cartridge 30M stores magenta ink, the ink cartridge 30C stores cyan ink, and the ink cartridge 30K stores black ink. be accommodated.

Further, each ink cartridge 30 is configured to be removable from the apparatus main body 1a of the image forming apparatus 1, and is connected to the corresponding inkjet head 10. Each ink cartridge 30 supplies ink of each color to each inkjet head 10 under the control of the control device 100.

The paper feeding device 50 is arranged below the inkjet head 10 . The paper feeding device 50 includes a single (or a plurality of) paper storage bodies 51 that accommodate recording sheets 5 of a desired size, type, etc. in a stacked state, and a feeding device that feeds out the recording sheets 5 one by one from the paper storage bodies 51. It is mainly composed of 52 and 53. The paper container 51 is attached, for example, so that it can be pulled out to the front side (the side facing the operator during operation) of the apparatus main body 1a.

As the recording paper 5, in addition to uncoated paper such as plain paper, coated paper such as coated paper or art paper, which has lower ink absorption than uncoated paper, can be used. Note that coated paper is paper in which a surface layer is formed with filler or binder resin. As the filler, for example, calcium carbonate, magnesium carbonate, kaolin, talc, silica, alumina, titanium dioxide, aluminum hydroxide, zinc oxide, etc. are used. Further, as the binder resin, for example, latex such as styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc. is used.

The transport device 40 includes a plurality of paper transport rollers 41 that transport the recording paper 5 sent out from the paper feeder 50 through an image forming position and transport the recording paper 5 to a discharge storage section 48 provided at the top of the apparatus main body 1a. - 46 and a paper conveyance path 47 consisting of a conveyance guide (not shown) is provided. The paper transport roller 42 arranged in the paper transport path 47 at a position immediately before the image forming position is configured as a roller (registration roller) that adjusts the transport timing of the recording paper 5, for example. Further, the paper conveyance roller 46 disposed at a position immediately in front of the ejection storage section 48 is configured as an ejection roller that ejects the recording paper 5 on which an image is formed to the ejection storage section 48 .

In the illustrated example, a fixing device S that fixes the image formed on the recording paper 5 by the inkjet head 10 is arranged downstream of the inkjet head 10 along the conveyance direction of the recording paper 5. Note that the fixing device S does not necessarily have to be provided.

<Configuration of image reading device>
FIG. 2 is a schematic configuration diagram showing the configuration of the image reading device according to the first embodiment.

The image reading device 3 is roughly divided into a casing 31, which is an example of the main body of the image reading device 3, and has a document reading surface (supporting surface) formed on the upper end surface, and a casing 31 that is attached to the casing 31 so as to be openable and closable. , an automatic document feeder (DADF: Duplex Automatic Document Feeder) 33 is provided as an example of document holding means for holding down the document 6. The automatic document feeder 33 is provided with a document holding cover 32 . Note that the document holding means is not limited to the automatic document feeding device 33, and may be constructed from the document holding cover 32 itself without the automatic document feeding device 33.

The automatic document feeder 33 separates the originals 6 set (placed) on the automatic document feeder 33 one by one and transports them to the reading position. It is equipped with a drive motor as a drive source for driving the conveying member. Therefore, the automatic document feeder 33 tends to be heavier as a whole.

The image reading device 3 operates in a first reading mode in which an image of the document 6 is read while automatically conveying the document 6 one by one by the automatic document feeder 33 in response to an operation by an operator, and in a document table 83 to be described later. It is configured to be automatically switchable to a second reading mode in which an image of the original 6 placed on the original and held by the original pressing cover 32 is read. FIG. 2 shows the state of each member when reading a document in the first reading mode.

The automatic document feeder 33 includes a document storage section 70, which is an example of a sheet stacking section capable of stacking and accommodating a plurality of documents 6 with the reading surface (first surface) facing upward, and a document storage section 70 that is an example of a sheet stacking section capable of storing a plurality of documents 6 with the reading surface (first surface) facing upward. A nudger roller 71 as an example of a feeding means for sending out the original 6; a feed roller 72 as an example of a feeding means for separating and feeding the original 6 sent out by the nudger roller 71 one by one; a pressure pad 72a that separates the original 6 one by one; a first transport roller 73 that transports the original 6 to the reading position; and a transport roller 74 that transports the original 6 transported by the first transport roller 73 so that it passes the reading position. , 75, and a discharge roller 77 as an example of a second conveyance roller that discharges the document 6 to the discharge storage section 76. These nudger roller 71, feed roller 72, transport rollers 73 to 75, and discharge roller 77 are driven when reading the original 6. The first conveyance roller 73 is a registration roller that adjusts the timing of conveyance of the document 6 to the reading position. In the first embodiment, although not explicitly described as a pair of rollers, the terms conveyance roller and discharge roller include a pair of rollers.

Further, the first conveyance roller 73 is a correction unit that mechanically corrects the inclination of the document 6 with respect to the conveyance direction (hereinafter referred to as "skew correction") and corrects the edge of the document 6 in the same direction as the conveyance direction. It also functions as As shown in FIG. 2, the conveying roller 73b as a driving roller of the first conveying roller 73 is rotated from a stopped state to the normal rotation direction Ra in the figure at a predetermined timing using a drive motor or the like as a driving means. Driven to rotate. The conveyance roller 73a, which is a driven roller, rotates according to the conveyance roller 73b while being in pressure contact with the conveyance roller 73b.

While the transport roller 73b serving as a driving roller is stopped, the first transport roller 73 is configured such that while the transport roller 73b serving as a driving roller is stopped, the leading edge of the document 6 transported by the feed roller 72 located upstream along the transport direction of the document 6 is transported. It abuts against the pressure contact portion between the roller 73b and the conveyance roller 73a. Then, the first conveyance roller 73 bends the leading edge region of the document 6 to align the leading edge of the document 6 with the axial direction of the first conveyance roller 73, and then starts conveying the document 6, thereby correcting the skew. I do.

The automatic document feeder 33 also includes a curved reading guide 78 that guides the original 6 to the reading position and guides the original 6 in the ejection direction from the reading position, and a curved reading guide 78 that is provided on the reading guide 78 above the reading window 79 and that guides the original 6 to the reading position. a first size detection sensor 81 that is provided in the document storage section 70 and detects the size of the document 6 in the sub-scanning direction; and a second size detection sensor 82 that detects the size in the sub-scanning direction.

The casing 31 of the image reading device 3 is formed as a rectangular parallelepiped box with a partially open upper end surface. The casing 31 includes an upper wall 312 facing the document holding cover 32, a bottom wall 313 facing the top wall 312, and side walls 314 facing in the sub-scanning direction (horizontal direction in FIG. 2) with the bottom wall 313 in between. It has a side wall 315, the above-mentioned front wall 311 (see also FIG. 1), and a rear wall 316 that faces the front wall 311 along the main scanning direction (direction perpendicular to the paper surface of FIG. 2). ing.

A large opening 317 having a planar rectangular shape is formed in the upper wall 312 of the housing 31 at a portion corresponding to the document reading position of the document 6 read in the second reading mode. A transparent document table 83 (platen glass) that supports the document 6 is arranged in the opening 317 . Further, a transparent reading window 79 is provided on the automatic document feeder 33 side of the document table 83 for reading the document 6 in the first reading mode. A guide member 84 having an inclined upper end surface is provided between the reading window 79 and the document table 83 to guide the document 6 that has passed the reading position in the first reading mode to the conveying roller 75.

The image reading device 3 includes a light source 85, which is an example of illumination means, such as an illumination lamp or an LED that irradiates light for illuminating the original 6, and a portion of the light emitted from the light source 85, inside the casing 31. a reflector 86 that reflects the light toward the original 6; a first mirror 87 that receives the reflected light from the original 6; a second mirror 88 that receives the reflected light from the first mirror 87; A third mirror 89 receives the reflected light from the mirror 88 of The image reading section includes an imaging lens 91 that forms an image on an image reading element 90, and the like. The light source 85 emits light toward the original 6 and the reflector 86 . The first to third mirrors 87 to 89 and the imaging lens 91 constitute a reading optical system for reading the image of the original 6 with the image reading element 90.

The light source 85, the reflector 86, and the first mirror 87 are arranged along the main scanning direction, which is the depth direction of the image reading device 3, and are arranged along the sub-scanning direction, which is the width direction of the image reading device 3. It is attached to a first moving body 92 consisting of a carriage configured to be movable. The first moving body 92 is guided by a first rail 93. The first movable body 92 illuminates the reading target area of the document 6 while moving along the sub-scanning direction, and the first mirror 87 directs the reflected light from the document 6 to the second movable body 94 . It is reflected toward mirror 88. The first rail 93 is arranged on the rear wall 316 of the housing 31 along the sub-scanning direction.

Further, the second mirror 88 and the third mirror 89 are arranged along the main scanning direction and attached to a second moving body 94 consisting of a carriage provided movably by a drive means along the sub-scanning direction. It is being The second moving body 94 reflects the reflected light from the original 6 toward the imaging lens 91 of the image reading section while moving in the sub-scanning direction guided by the second rail 95 . The second rail 95 is arranged on the bottom wall 313 of the housing 31 along the sub-scanning direction. One first rail 93 and one second rail 95 are arranged so as to face each other at both ends along the main scanning direction.

As shown in FIG. 9, the first and second movable bodies 92 and 94 are driven by a drive pulley or a drive motor 34 (not shown), which is an example of a drive source disposed inside the casing 31 of the image reading device 3. It is driven via a drive wire or the like so that it can reciprocate along the sub-scanning direction.

The image reading section has an image reading board 97 on which an image reading element 90 is mounted, as shown in FIG. The imaging lens 91 and the image reading board 97 are attached to a base plate 96 supported by the bottom wall 313. In the image reading section, the reflected light from the third mirror 89 passes through an imaging lens 91 and forms an image on an image reading element 90 made of a CCD, CMOS, etc., and the image reading element 90 reads the image of the original 6. Output data. The image data read by the image reading element 90 is subjected to predetermined image processing such as shading correction as necessary by an image processing device (not shown), and is sent to the control device 100 (see FIG. 1).

In the first reading mode, as shown by solid lines in FIG. The document 6 is automatically conveyed by the automatic document feeder 33, the document 6 passing above the reading window 79 is illuminated by a light source 85, and the reflected light image from the document 6 is transferred to the second and second mirrors by the first mirror 87. It is reflected to the imaging lens 91 via mirrors 88 and 89 of No. 3. The image reading unit forms the reflected light image from the third mirror 89 on an image reading element 90 using an imaging lens 91, reads the image of the document 6 with the image reading element 90, and reads image data from the image reading element 90. Output.

On the other hand, in the second reading mode, the first movable body 92 and the second movable body 94 are driven by a drive source to be described later, and while the first movable body 92 moves along the sub-scanning direction, the original The moving amount of the second moving body 94 is configured to be 1/2 of the moving amount of the first moving body 92 so that the optical path length from the image reading position No. 6 to the image reading element 90 does not change. . In FIG. 2, two-dot chain lines indicate the positions of the first moving body 92 and the second moving body 94 when the first moving body 92 moves near the end of the document 6 in the sub-scanning direction.

As shown in FIG. 3, the image reading device 3 separates the originals 6, which are examples of sheets stored in the original storage unit 70, one by one and transports them to a reading position, and also collects the sheets that have passed through the reading position. A sheet conveying device 320 is provided that switches back and conveys the sheet again to the reading position in a reversed state. The sheet conveyance device 320 includes a nudger roller 71, a feed roller 72, a pressure pad 72a, a first conveyance roller 73, conveyance rollers 74 and 75, a discharge roller 77, and a drive source that drives these rollers. A drive motor 321, a fixed direction rotation mechanism 322 that rotates the first conveyance roller 73 in a fixed direction regardless of the rotational direction of the drive motor 321, and a state in which driving force is transmitted to the first conveyance roller 73 and a state in which it is not transmitted. and a second drive transmission switching means 324 that switches between transmitting and not transmitting the driving force to the feed roller 72 and nudger roller 71. In addition, in FIG. 3, the broken line indicates the transmission path of the driving force.

As shown in FIG. 3, the sheet conveyance device 320 conveys the document 6 conveyed by the nudger roller 71 so as to pass through a feed roller 72, a first conveyance roller 73, conveyance rollers 74 and 75, and a discharge roller 77. The document 6 whose rear end is held by the normal conveyance path 325 and the discharge roller 77 is reversed by reversing the rotational direction of the discharge roller 77 to reverse the document 6 and convey it to the first conveyance roller 73 again. A reversing conveyance path 326 is provided. The normal transport path 325 is divided into a plurality of parts along the normal transport path 325, and includes guide members 325a and 325b that guide the front and back sides of the document 6, a reading guide 78, and a back support member 80. The reversing conveyance path 326 includes guide members 326a and 326b that guide the front and back sides of the document 6. Furthermore, a switching gate 327 is provided at a branching position where the normal transport path 325 and the reverse transport path 326 are separated to switch the transport path of the document 6 from the normal transport path 325 to the reverse transport path 326. The switching gate 327 is made of an elastically deformable synthetic resin film or the like having a substantially Y-shaped cross section. As shown in FIG. 3, the switching gate 327 is usually arranged so that a part thereof diagonally crosses the normal conveyance path 325. When the document 6 is conveyed along the normal conveyance path 325 to the ejection roller 77, the switching gate 327 is pushed by the document 6 and elastically deforms to open the normal conveyance path 325, thereby changing the direction of conveyance of the document 6. is switched to the discharge roller 77. On the other hand, the switching gate 327 reverses the rotational direction of the ejection roller 77 while the ejection roller 77 is holding the rear end of the document 6, so that the document 6 is transferred to the first conveyance roller 73 along the reversal conveyance path 326. When conveying the document 6 to the document 6, the conveyance path of the document 6 conveyed by the discharge roller 77 is switched from the normal conveyance path 325 to the reverse conveyance path 326.

The sheet conveying device 320 includes a document sensor 328 that detects the leading edge of the document 6 at a position corresponding to the nudger roller 71. Further, a pre-registration sensor 329 for detecting the leading edge of the document 6 is provided on the upstream side of the first conveyance roller 73 along the conveyance direction of the document 6 . Furthermore, the sheet conveyance device 320 is disposed downstream of the conveyance roller 74 along the conveyance direction of the document 6, and includes a registration sensor (not shown) that detects the leading edge of the document 6, and a registration sensor (not shown) arranged downstream of the conveyance roller 74 along the conveyance direction of the document 6. An inverter sensor (not shown) is provided on the upstream side and detects the rear end of the document 6.

Note that the sheet conveying device 320 is configured to read the image on the back side of the original 6 by conveying the original 6 to the reversing conveying path 326, but instead of providing the reversing conveying path 326, a normal By arranging a second image reading element (not shown) that reads images on the back side (second side) of the original 6 in the middle of the transport path 325, images on both the front and back sides of the original 6 can be obtained without reversing the transport direction of the original 6. may be configured to be readable.

In this case, the reversing conveyance path 326 becomes unnecessary, but it is necessary to newly arrange the second image reading element. Therefore, in the image reading device 3, since the second image reading element itself has a certain amount of weight, the automatic document feeder 33 may become even heavier.

<Configuration of main parts of image reading device>
As shown in FIG. 4, the image reading device 3 according to the first embodiment includes an automatic document feeder 33 as an example of document pressing means. The automatic document feeder 33 is provided with the document holding cover 32 as described above. A holding member 32a formed in the shape of a white sheet is provided on the lower surface of the document holding cover 32 to hold down a document (not shown) placed on the document table 83. The pressing member 32a is formed into a planar rectangular shape having approximately the same size as the document table 83. The automatic document feeder 33 separates the originals 6 set on the automatic document feeder 33 one by one and transports them to a reading position. The apparatus is provided with conveyance members such as one conveyance roller 73, conveyance rollers 74 and 75, and discharge roller 77, and a drive motor 321 (see FIG. 3) as a drive source for driving these conveyance members. Therefore, as described above, the automatic document feeder 33 tends to be heavier as a whole.

In the second reading mode, the image reading device 3 does not require the operator to manually open and close the automatic document feeder 33 when placing the document 6 on the document table 83 and reading the image of the document 6. be. Therefore, in the image reading device 3, as the weight of the automatic document feeder 33 increases, the operating force required to open and close the automatic document feeder 33 increases accordingly. Therefore, it is desired that the image reading device 3 has improved operability by reducing the operating force required when opening and closing the automatic document feeder 33.

As a technique that can improve the operability when opening and closing the automatic document feeder 33, as described in the above-mentioned Patent Document 1, the opening/closing angle of the automatic document feeder 33 is detected, and the opening/closing angle of the automatic document feeder 33 is detected. A technique for controlling the opening/closing speed of the automatic document feeder 33 according to the opening/closing angle of the automatic document feeder 33 has already been proposed.

However, if the image reading device 3 is configured to detect the opening/closing angle of the automatic document feeder 33 and control the opening/closing speed of the automatic document feeder 33 according to the opening/closing angle of the automatic document feeder 33, the automatic document If you open or close the automatic document feeder 33 when a heavy object such as a book is placed on the conveyor 33, an excessive load will be applied to the drive means that opens and closes the automatic document feeder 33, causing the drive This poses a technical problem in that there is a risk that the gears of the device may be damaged or the opening/closing operation may malfunction, impairing operability.

Therefore, the image reading device 3 according to the first embodiment includes an automatic document feeder 33 that is attached to a housing 31 so as to be openable and closable, and that transports the document 6 to the reading position, and an automatic document feeder 33 that is driven when the automatic document feeder 33 is opened. The apparatus is configured to include a pulling force applying means for temporarily acting on the driving force of the motor 34 as a pulling force for pulling up the automatic document feeder 33 in the opening direction.

Further, in the image reading device 3 according to the first embodiment, the pulling force applying means includes a pulling force applying member rotatably disposed inside the automatic document feeder 33 about a rotation axis, and The force applying member is configured to have a wire member that applies a pulling force in the direction of opening the automatic document feeder 33 to an end located on the opposite side to the rotation axis of the force applying member.

That is, in the image reading device 3 according to the first embodiment, as shown in FIG _{. 432} so that it can be opened and closed. The first and second shaft support members 43 ₁ , 43 ₂ have bearing parts 44 ₁ , 44 ₂ provided on the side of the casing 31 of the image reading device 3, and reading rotation parts provided on the side of the automatic document feeder 33. 45 ₁ and 45 ₂ . The bearing parts 44 ₁ , 44 ₂ and the reading rotation parts 45 ₁ , 45 ₂ are rotatably connected around the rotation shafts 46 ₁ , 46 ₂ , as shown in FIG. 5 . The reading rotation units 45 ₁ and 45 ₂ have built-in counterbalances (not shown) that apply a rotational moment in the opening direction to the automatic document feeder 33 in order to reduce the load when opening and closing the automatic document feeder 33. ing. The counterbalance includes a coil spring (not shown) that applies a rotational moment in the opening direction to the automatic document feeder 33 in accordance with the opening/closing angle of the automatic document feeder 33. Note that the counterbalance may of course be placed on the bearing portions 44 ₁ and 44 ₂ side.

In addition, the original 6 whose image is read by the image reading device 3 is not limited to an original 6 cut into a desired size such as A4 size or A3 size, but also a multi-page original 6 such as a closed book. It also includes a so-called book manuscript having a manuscript 6 spanning the entire range. To read the image of a book document using the image reading device 3, as shown in FIG. , an operation is performed to close the automatic document feeder 33.

In this case, since the book document has a certain thickness, the automatic document feeder 33 is simply provided so that it can be opened and closed using the first and second shaft support members 43 ₁ and 43 ₂ as fulcrums. Even if the automatic document feeder 33 is closed when reading an image of a book document, the automatic document feeder 33 is tilted with respect to the top surface of the book document and cannot hold the entire surface of the book document.

Therefore, the first and second shaft support members 43 ₁ and 43 ₂ that support the automatic document feeder 33 in an openable and closable manner are attached to the casing of the image reading device 3, as shown in FIGS. 5(b) and 5(c). The bearing parts 44 ₁ and 44 ₂ arranged on the 31 side are provided with cylindrical lifting parts 44 ₁ a and 44 ₂ a. The elevating parts 44 _{1 a} , 44 ₂ a of the bearing parts 44 ₁ , 44 ₂ are inserted into and removed from the hole 31 a provided in the housing 31 . The first and second supporting members 43 ₁ and 43 ₂ are inserted into the hole 31 a provided in the housing 31 when reading an image of a document 6 having a certain thickness such as a book document. The lifting parts 44 ₁ a, 44 _{2 a} of the bearing parts 44 ₁ , 44 ₂ are moved upward, and the automatic document feeder 33 is able to press the entire surface of the book original so that it is approximately parallel to the top surface of the book original. It is configured to be possible.

As shown in FIG. 4, the automatic document conveyance device 33 has a left end in the figure that has a built-in conveyance means for automatically conveying the document 6, and is heavier than the right side. As a result, the center of gravity of the automatic document feeder 33 is located at a position that is biased toward the left side in the figure, where the conveyance means for automatically conveying the document 6 is built in, rather than the center portion along the width direction. Therefore, regarding the counterbalances built into the first and second shaft support members 43 ₁ and 43 ₂ , the first counterbalance located on the left side in the figure, which is the drive side of the automatic document feeder 33, is more The rotational moment applied to the automatic document feeder 33 is set to be larger than that of the second counterbalance disposed on the right side, which is the non-driving side, of the automatic document feeder 33.

FIG. 6 shows the rotational moment M1 required to open the automatic document feeder 33 from the closed state (opening angle = 0 degrees) and the rotation given to the automatic document feeder 33 by the first shaft support member ₄₃₁ . The moment M2, the rotational moment M3 that the second shaft support member ₄₃₂ gives to the automatic document feeder 33, and the combined rotational moment that the first and second shaft support members ₄₃₁ , ₄₃₂ give to the automatic document feeder 33. 7 is a graph showing the results of determining each value of MT according to the opening/closing angle of the automatic document feeder 33. FIG.

In the image reading device 3 according to the first embodiment, in order to reduce the operating force of the operator when opening the automatic document feeder 33 as much as possible, the automatic document feeder 33 is tilted at a predetermined angle of about 5 to 25 degrees. When opened at an angle θ (for example, 10 degrees), the value of the rotational moment M1 required to open the automatic document feeder 33 and the combined rotational moment MT of the first and second shaft support members 43 ₁ and 43 ₂ is are set to be equal. Furthermore, when the opening angle of the automatic document feeder 33 exceeds a predetermined angle θ, the rotational moment M1 required to open the automatic document feeder 33 causes the first and second shaft supporting members 43 ₁ , The resultant rotational moment MT of ₄₃₂ is set to be larger. As a result, the operator can easily open the automatic document feeder 33 in an angular range exceeding the predetermined angle θ even when the weight of the automatic document feeder 33 increases. However, even if the opening angle of the automatic document feeder 33 exceeds a predetermined angle θ, the first and second shaft supporting members 43 ₁ , 43 ₂ are It is desirable to prevent the automatic document feeder 33 from opening involuntarily when the opening operation is stopped. Therefore, even if the opening angle of the automatic document feeder 33 exceeds a predetermined angle θ, the first and second shaft supporting members 43 ₁ , 43 ₂ The structure is such that a frictional force is applied to maintain the opening angle when the hand is released.

Furthermore, even when the automatic document feeder 33 is in a completely closed state (opening angle = 0 degrees), a composite rotational moment MT in the opening direction acts on the first and second shaft supporting members 43 ₁ and 43 ₂ . ing. At this time, the required combined rotational moment MT acting on the automatic document feeder 33 by the first and second shaft support members 43 ₁ and 43 ₂ is larger than the amount required to open the automatic document feeder 33 as shown in FIG. This value is only ΔM smaller than the rotational moment M1 required for this purpose.

As shown in FIG. 5A, the image reading device 3 includes a reed switch 220 and a magnetic member 221 as an example of a detection means for detecting whether the automatic document feeder 33 is opened or closed. For example, a reed switch 220 is provided in the housing 31 of the image reading device 3 in front of the reading window 79. As shown in FIG. 7, the reed switch 220 includes a first reed 222 made of a ferromagnetic material with one end magnetized as an S pole and the other end as an N pole, and a first lead 222 as shown in FIG. A second lead 223 made of a ferromagnetic material whose portion is magnetized to the south pole is sealed inside the switch body 224 . First and second contact portions 225 and 226 are provided at the other end of the first lead 222 and the other end of the second lead 223, respectively. The reed switch 220 is attached so that the second lead 223 is located on the front side of the housing 31.

On the other hand, a magnetic member 221 is attached to the automatic document feeder 33 at a position corresponding to the reed switch 220 of the casing 31 of the image reading device 3 . The magnetic member 221 is made of an elongated permanent magnet with an S pole and an N pole magnetized at both ends. The magnetic member 221 is arranged so that the S magnetic pole is located on the lower surface side of the automatic document feeder 33.

Then, as shown in FIGS. 7(b) and 8, when the automatic document feeder 33 is closed, the reed switch 220 connects the magnetic member 221 to the second contact portion 226 of the S pole of the second lead 223. When the south poles are close to each other, the second contact part 226 of the south pole is magnetically repulsive, and the first contact part 225 of the north pole is magnetically attractive, so that the second contact part 226 of the south pole in the second lead 223 contacts the N-pole first contact portion 225 of the first lead 222 and turns on. On the other hand, as shown in FIGS. 5(a) and 7(a), when the automatic document feeder 33 is opened, the reed switch 220 separates the S pole of the magnetic member 221 from the reed switch 220, and separates from the N pole. Due to the elastic restoring force of the first contact portion 225 and the second contact portion 226 of the S pole, the second contact portion 226 of the second lead 223 is connected to the first contact portion 225 of the first lead 222. It becomes the off state by separating from.

In this way, the reed switch 220 can detect the opening and closing of the automatic document feeder 33 with a simple configuration and with high accuracy by determining whether it is in the on state or the off state.

Note that the detection means for detecting the opening/closing of the automatic document feeder 33 is not limited to the combination of the reed switch 220 and the magnetic member 221; A mechanical switch having a contact member that appears and disappears when the automatic document feeder 33 is opened or closed, or an optical switch that optically detects whether the automatic document feeder 33 is opened or closed may be used.

As shown in FIG. 5, in the image reading device 3 according to the first embodiment, when the operator opens the automatic document feeder 33, the driving force of the drive source is applied to the automatic document feeder 33 to automatically convey the document. A pulling device 200 is provided on the back side inside the casing 31 of the image reading device 3 as an example of a pulling force acting means that only temporarily acts as a pulling force to pull up the device 33 in the opening direction.

In this first embodiment, as shown in FIG. 9, the lifting device 200 does not have its own drive source, but uses the drive motor 34 that drives the reading optical system of the image reading device 3 as the drive source. ing. Note that, of course, the pulling device 200 may be provided with its own driving source.

As shown in FIG. 10, the drive shaft 341 of the drive motor 34 is attached with a drive gear 202 that drives the pulling device 200 together with a drive pulley 201 that drives the reading optical system. As shown in FIG. 9, a timing belt 204 is wound around the drive pulley 201 and a driven pulley 203 that drives the reading optical system of the image reading device 3.

As shown in FIG. 10, the drive motor 34 is driven to rotate in the forward and reverse directions when reading the image of the document 6 in the second reading mode. A driving force transmission gear 205 having a built-in electromagnetic clutch 205c as an example of a switching means for switching whether or not to transmit the rotational driving force of the drive motor 34 to the pulling device 200 is meshed with the driving gear 202. The driving force transmitting gear 205 includes a first driving force transmitting gear 205a on the input side having a relatively large outer diameter, and a second driving force transmitting gear 205b on the output side having a relatively small outer diameter. . A reciprocating gear 208 that reciprocates a drive wire 206, which is an example of a wire member, is meshed with the second driving force transmission gear 205b.

The reciprocating gear 208 is provided with an engagement pin 209 at the outer peripheral end of one side thereof so as to protrude laterally. One end of a drive wire 206 is rotatably engaged with the engagement pin 209 .

As shown in FIG. 9, the drive wire 206 has its horizontal end hooked around a first pulley 210 rotatably provided inside the casing 31 of the image reading device 3. The direction of the tip is changed upward along the vertical direction. The tip of the drive wire 206 is passed around a second pulley 211 that is rotatably provided at a position corresponding to the first shaft supporting member ₄₃₁ on the back side of the automatic document feeder 33, and then the drive wire 206 is rotated around a second pulley 211 that is rotatably provided at a position corresponding to the first shaft support member 431 on the back side of the automatic document feeder 33. It is introduced inside the device 33.

Inside the automatic document feeder 33, as shown in FIG. 5(a), an opening arm member 212 formed in an elongated plate shape rotates about the rotation shaft 46 ₁ of the first shaft support member 43 ₁ as a fulcrum. Possibly located. The opening arm member 212 extends so that its tip is located near the front end of the automatic document feeder 33 . The tip of the drive wire 206 is connected and fixed to the tip 212a of the opening arm member 212. The opening arm member 212 is integrally provided with a short working arm 212c that branches upward in the vertical direction from a middle portion along the longitudinal direction. The working arm 212c of the opening arm member 212 has its tip abutting against a ceiling wall 33a provided above the automatic document feeder 33.

When the reciprocating gear 208 is rotated in a predetermined direction by rotationally driving the drive motor 34, the lifting device 200 has one end rotatably engaged with an engagement pin 209 provided on the reciprocating gear 208. The driven wire 206 is pulled and moved to the left in FIG. The movement of the drive wire 206 is transmitted to the opening arm member 212 disposed inside the automatic document feeder 33 via the first and second pulleys 210 and 211, and the opening arm member 212 rotates clockwise in FIG. Rotate in the direction. When the opening arm member 212 rotates clockwise in FIG. 5, the tip of the operating arm 212c comes into contact with a ceiling wall 33a provided at the top of the automatic document feeder 33, causing the automatic document feeder 33 to move clockwise. Pull up along.

Then, as the opening arm member 212 rotates clockwise in the figure, the ceiling wall 33a of the automatic document feeder 33 is pulled up by the working arm 212c of the opener arm member 212, and the operator can move the automatic document feeder 33 upward. It is designed to assist in the opening action.

The distal end portion 212a of the opening arm member 212 along its longitudinal direction serves as a force point to which a pulling force is applied by the drive wire 206. Further, in the opening arm member 212, the tip of the operating arm 212c located in the middle along the longitudinal direction serves as a point of action that actually applies a lifting force to the ceiling wall 33a of the automatic document feeder 33. Therefore, in the pulling device 200, the distance from the base end 212b to the front end 212a and the base end 212b are determined by the drive wire 206 against the rotational moment that rotates the front end 212a of the opening arm member 212 in the clockwise direction in the figure. A large pulling force is applied due to the action of the lever, which is proportional to the distance from to the working arm 212c.

When the operator opens the automatic document feeder 33 , the drive motor 34 is driven only temporarily for a predetermined time T and pulls up the automatic document feeder 33 via the drive wire 206 . It stops after opening by a set angle several degrees (1 to 2 degrees) larger than a predetermined angle θ, and is immediately rotated in the opposite direction to complete the lifting operation of the automatic document feeder 33.

Note that the drive wire 206 is not rotatably connected to the reciprocating gear 208 via the engagement pin 209, but is provided with a take-up reel (not shown) in place of the reciprocating gear 208, and one end of the drive wire 206 is connected to the reciprocating gear 208 via the engagement pin 209. It may be configured such that it is fixed to a take-up reel and the drive wire 206 is wound up by the take-up reel.

By the way, in the image reading device 3 according to the first embodiment, when a heavy object such as a book is placed on the automatic document feeder 33 with the automatic document feeder 33 closed, Even if the drive wire 206 is driven, the automatic document feeder 33 will not open, and there is a risk that an excessive load will be applied to the drive motor 34 that drives the drive wire 206.

Further, in the image reading device 3 according to the first embodiment, after the operator performs an operation to open the automatic document feeder 33, the automatic document feeder An operation to close the device 33 may be performed. Then, while the image reading device 3 is driving the drive wire 206 to open the automatic document feeder 33 by a predetermined angle θ, the automatic document feeder 33 is forcibly closed and the drive wire 206 is opened. There is a possibility that an excessive load will be applied to the drive motor 34 to be driven.

Therefore, the image reading device 3 according to the first embodiment includes an absorbing means 240 that absorbs an excessive force exceeding a predetermined value when it is applied to the pulling device 200. The absorbing means 240 is composed of, for example, an elastic member that absorbs excessive force by elastically deforming when excessive force is applied to the pulling device 200.

To explain further, in the image reading device 3, a coil spring 241 as an example of an absorbing means 240 is interposed in the middle of the drive wire 206 that transmits the driving force of the drive motor 34 to the automatic document feeder 33 as a pulling force. . The coil spring 241 has a required spring constant. The spring constant of the coil spring 241 is greater than the tension that acts on the drive wire 206 when the drive wire pulls up the automatic document feeder 33, such as when a heavy object is placed on the automatic document feeder 33. The tension is set to a value smaller than the tension when a load exceeding a predetermined value is applied to the pulling device 200. Therefore, the coil spring 241 extends to a certain length L2 when the drive wire pulls up the automatic document feeder 33, but the length L2 of the coil spring 241 is different from the length L2 of the coil spring 241 as shown in FIG. 200 is shorter than the length L3 when a load exceeding a predetermined value is applied. Note that the coil spring 241 has a length of L1 before tension is applied to the drive wire 206.

In this first embodiment, when an excessive load is applied to the drive motor 34, the coil spring 241 is expanded to absorb the excessive load acting on the drive motor 34. This prevents the drive motor 34 from generating heat and breaking due to overload, and the reciprocating gear 208 that transmits the driving force from chipping or losing synchronization.

FIG. 13 is a block diagram showing the control device 100 of the image forming apparatus 1 according to the first embodiment.

As shown in FIG. 13, the control device 100 includes a control section 101 as an example of a control means, a clock section 102 that measures time, and a storage section 103 as an example of a storage means.

The control unit 101 comprehensively controls the operation of the image forming apparatus 1 including the image reading operation by the image reading device 3 by executing a program stored in the storage unit 103 . The control unit 101 drives the image forming unit 2, which includes yellow (Y), magenta (M), cyan (C), and black (K) inkjet heads 10 (Y, M, C, K), etc. , executes an operation of forming a color image, etc.

Further, the control unit 101 controls the reading operation of the image reading device 3 via the clock unit 102, the storage unit 103, and the like.

At this time, when the control unit 101 detects that the automatic document feeder 33 has shifted from the closed state to the open state based on the open/close signal of the automatic document feeder 33 inputted from the reed switch 220, the control unit 101 controls the drive motor. 34 for a predetermined time T (temporarily only). Here, the predetermined time T is set, for example, to the time required for the drive motor 34 to open the automatic document feeder 33 by a set angle that is several degrees (1 to 2 degrees) larger than the predetermined angle θ. be done.

At the same time, the timer 102 measures the elapsed time when it detects that the automatic document feeder 33 has transitioned from the closed state to the open state based on the open/close signal of the automatic document feeder 33 inputted from the reed switch 220. measure. When the timer 102 measures that a predetermined time T has elapsed, it outputs a elapsed signal to the controller 101.

When the control unit 101 receives the elapsed signal output from the clock unit 102, it controls the drive motor 34 to stop, and then rotates the drive motor 34 in the opposite direction for a predetermined time T, and then stops the drive motor 34. do.

Further, the control unit 101 turns on and off the electromagnetic clutch 205c at a required timing. The timing at which the control unit 101 turns on the electromagnetic clutch 205c is set when it detects that the automatic document feeder 33 is opened based on the open/close signal of the automatic document feeder 33 inputted from the reed switch 220. Ru. Further, the timing at which the control unit 101 turns off the electromagnetic clutch 205c is set when a predetermined time T has elapsed since the electromagnetic clutch 205c was turned on.

<Operation of image reading device>
In the image forming apparatus 1 to which the image reading apparatus 3 according to the first embodiment is applied, when copying the image of the original 6 or reading the image of the original 6 and transmitting it using a facsimile function or the like, Compared to the case where the automatic document feeder 33 in the image reading device 3 is driven to open and close over all opening and closing angles, it is possible to reduce the operating force when opening the automatic document feeder 33 without impairing operability. It has become.

That is, in the image reading device 3 of the image forming apparatus 1, when reading the image of the document 6 in the second reading mode, as shown in FIG. The original 6 is placed on the original table (platen glass) 83 provided on the upper end surface of the housing 31 of the reading device 3, and after the automatic document feeder 33 is closed, the desired Executes copy operations, etc.

The image reading device 3 reads the image of the document 6 according to the operation specified on the control panel 66, and forms the image of the document 6 on the recording paper 5 by the image forming section 2 of the image forming device 1. , transmits the image of the document 6 read by the image reading device 3 to a personal computer (not shown), or transmits the image of the document 6 read by the image reading device 3 using a facsimile function.

In the image reading device 3 that reads the image of the original 6, an automatic document feeder 33 is equipped with a transport member, a drive motor 321, etc. for automatically transporting the original 6 in the first reading mode, and the image reading device 3 reads the image of the original 6. It is heavy. Therefore, in the image reading device 3, in the second reading mode, when reading the image of the document 6 while holding the document 6 on the document table 83 with the automatic document feeder 33, the relative The operator is required to open and close the automatic document feeder 33, which is heavy.

When the operator opens the automatic document feeder 33, the image reading device 3 detects via the reed switch 220 that the automatic document feeder 33 has been opened.

As shown in FIG. 13, when the control unit 101 of the control device 100 detects that the automatic document feeder 33 is opened due to the signal from the reed switch 220 transitioning from the on state to the off state, the control unit 101 reduces the driving force. At the same time as the electromagnetic clutch 205c of the transmission gear 205 is turned on, the drive motor 34 is driven to rotate for a predetermined time T (only temporarily).

In the image reading device 3, as shown in FIG. 9, when the drive motor 34 is rotationally driven, the drive force transmission gear 205 is rotationally driven by the drive motor 34. In the driving force transmission gear 205, since the electromagnetic clutch 205c is in the ON state, the rotational driving force from the drive motor 34 is transmitted to the second driving force transmission gear 205b, and the reciprocating gear 208 is rotated counterclockwise in the figure. It is rotated by a required angle in the rotational direction.

Then, a tension force is applied to the drive wire 206, one end of which is connected to the reciprocating gear 208, to the left in the figure, and the drive wire 206 is moved to the automatic document feeder 33 via the coil spring 241 and the first and second pulleys 210, 211. The distal end portion 212a of the opening arm member 212 disposed inside the opening arm member 212 is pulled up in the clockwise direction.

When the opening arm member 212 is pulled up clockwise by the drive wire 206 connected to its tip 212a, the opening arm member 212 itself also rotates clockwise. Then, the operating arm 212c provided in the middle of the opening arm member 212 comes into contact with the ceiling wall 33a of the automatic document feeder 33 and pulls up the automatic document feeder 33 in the opening direction, thereby opening the automatic document feeder 33.

Therefore, when the operator opens the automatic document feeder 33, the operation of opening the automatic document feeder 33 is assisted by the pulling-up operation of the drive wire 206. The operation of opening the transport device 33 can be easily performed.

Further, the angle at which the drive wire 206 opens the automatic document feeder 33 is set to a set angle that is several degrees (1 to 2 degrees) larger than a predetermined angle θ, as shown in FIG. Therefore, after the operator is assisted in opening the automatic document feeder 33 by the drive wire 206, the resultant rotation moment acting by the counterbalance built in the first and second shaft support members 43 ₁ and 43 ₂ is generated. The automatic document feeder 33 can be easily opened to the fully open position by the MT.

When the timer 102 measures that a predetermined time T has elapsed, the control unit 101 of the control device 100 stops the drive motor 34 and immediately rotates it in the opposite direction for a predetermined time T. let Further, the control unit 101 stops the drive motor 34 and simultaneously turns off the electromagnetic clutch 205c.

Then, as the drive motor 34 rotates in the opposite direction, the drive wire 206, one end of which is connected to the reciprocating gear 208, moves to the right in the figure, as shown in FIG. Move it to the right in the figure.

When the drive wire 206 moves to the right in the figure, the opening arm member 212 connected to the inside of the automatic document feeder 33 via the first and second pulleys 210 and 211 also rotates counterclockwise. It is separated from the ceiling wall 33a of the automatic document feeder 33.

Furthermore, in the first embodiment, when the electromagnetic clutch 205c is turned off, the second driving force transmitting gear 205b of the driving force transmitting gear 205 can freely rotate, and the operation of pulling the driving wire 206 is released. be done.

In this way, in the image reading device 3 according to the first embodiment, the reed switch 220 detects the operator's operation to open the automatic document feeder 33, and the drive motor 34 is driven, thereby controlling the drive wire 206 and the opening movement. The automatic document feeder 33 is pushed up only temporarily by the arm member 212. Therefore, even if the automatic document feeder 33 has a relatively large weight, the operation of opening the automatic document feeder 33 by the operator is assisted by the drive motor 34, and the operation to open the automatic document feeder 33 is assisted. It can be done easily.

Further, in the image reading device 3 according to the first embodiment, when a heavy object such as a book (not shown) is placed on the automatic document feeder 33, or when the operator is in the middle of opening the automatic document feeder 33, Even when a closing operation is performed, as shown in FIG. 14, since the coil spring 241 is interposed in the middle of the drive wire 206, the coil spring 241 expands by the length L3, thereby preventing excessive load. This prevents excessive loads from acting on the drive motor 34.

Therefore, according to the image reading device 3 according to the first embodiment, when opening and closing the automatic document feeder 33 without impairing operability, compared to the case where the automatic document feeder 33 is driven to open and close over all opening and closing angles. This makes it possible to reduce the operating force required.

In the above embodiment, the case where the image reading device is applied to a color copying machine as an example of an image forming device has been described, but the invention is not limited to this, and the image reading device can be used as a scanner, a fax machine, etc. Of course, it is good to do so.

Further, in the above embodiment, a case has been described in which a coil spring is used as the absorbing means, but the absorbing means may also be configured such that a torque limiter that limits the driving torque is provided in the driving force transmission gear 205 or the like. .

1... Image forming apparatus 1a... Image forming apparatus body 3... Image reading device 31... Image reading device housing 33... Automatic document feeder 34... Drive motor 206... Drive wire 207... Link mechanism 210... First pulley 211... Second pulley 212...opening arm member

Claims (8)

a document holding means that is attached to the main body of the apparatus so as to be openable and closable via a rotating shaft and that holds down the document;
a pulling force acting means for temporarily acting on the driving force of a drive source as a pulling force to pull up the document holding means in the direction of opening the document holding means when the document holding means is opened;
Equipped with
The pulling force acting means includes a pulling force acting member rotatably disposed inside the document pressing means with the rotating shaft as a fulcrum;
An image reading device including a wire member that applies a pulling force in a direction to open the document holding means to an end of the pulling force applying member located on the opposite side to the rotation axis. 2. The image reading device according to claim 1, wherein the pulling force applying member has an acting arm that branches from an intermediate position along the longitudinal direction and applies a pulling force in an opening direction to the document holding means. 3. The image reading device according to claim 2, wherein the pulling force applying means converts a moving direction of the wire member into an opening/closing direction of the document holding means via a pulley disposed in the middle of the wire member. 2. The image reading apparatus according to claim 1, further comprising an absorbing means for absorbing an excessive force exceeding a predetermined value when an excessive force exceeding a predetermined value is applied to the pulling force applying means. 5. The image reading device according to claim 4, wherein the absorbing means comprises an elastic member that absorbs the excessive force by elastically deforming when the excessive force is applied to the pulling force applying means. comprising an image reading means for reading an image of the document conveyed to a reading position by the document pressing means;
The image reading device according to claim 1, wherein the drive source is a drive source for the image reading means. 7. The image reading apparatus according to claim 6 , wherein when the document holding means is open, power to the drive source is cut off. an image reading means for reading an image of the original;
image forming means for forming an image of the document read by the image reading means;
Equipped with
An image forming apparatus using the image reading device according to claim 1 as said image reading means.

Images