JP4498166B2 - Automatic document feeder, image reading apparatus, and image forming apparatus - Google Patents

Description

  The present invention includes an automatic document feeder that automatically feeds a document to a reading unit, an image reading device that optically reads a document fed by the automatic document feeder, and the image reading device. More particularly, the present invention relates to a support structure for an automatic document feeder.

  Many image forming apparatuses such as copying machines are provided with an automatic document feeder for reading a document. An automatic document feeder mounted on this type of image forming apparatus is provided with an opening / closing support mechanism (hereinafter referred to as a “hinge”) for performing copying by placing a document directly on a contact glass. The hinge is provided with a balance mechanism including a cam and a spring (elastic body) to balance the weight of the automatic document feeder when the automatic document feeder is opened. The opening and closing operation of the feeding device can be easily performed.

  However, since the automatic document feeder itself is very heavy, a spring that supports the automatic document feeder has a strong elastic biasing force. Therefore, the position of the automatic document feeder becomes unstable due to variations in the elastic biasing force of the spring. In other words, when the elastic biasing force of the spring is strong, the automatic document feeder is in a state of floating from the contact glass surface, so that the document cannot be accurately conveyed, and when the elastic biasing force of the spring is weak, the automatic document Since the feeding device falls due to its own weight, there is a risk that the operator may come in contact with the operator. In particular, the decrease in the elastic biasing force of the spring is often caused by the use of the spring over time (long-term use).

  In order to recover such a decrease in the elastic force of the spring, the spring of the hinge may be replaced. As described above, the elastic biasing force (spring coefficient) of the spring attached to the hinge of the automatic document feeder is as described above. Is very large, a special large facility is required to replace the spring. Therefore, it is difficult to replace the spring during market maintenance and product reuse. Therefore, it is conceivable to replace the hinge itself when the elastic urging force of the spring is lowered. However, since the reference position of the automatic document feeder is generally determined by the hinge, the hinge is replaced without using a positioning jig in the market. In such a case, the accuracy of the product itself may be upset.

Therefore, as an automatic document feeder that can adjust the elastic biasing force of an elastic body such as a spring without disassembling or replacing the hinge, in Patent Document 1, for example, the elasticity of the spring is achieved by a screw attached to the spring. An automatic document feeder capable of adjusting the force has been proposed.
JP 2002-202640 A

  In the invention described in Patent Document 1, the adjusting screw is arranged on an extension line in the elastic direction of the spring. On the other hand, the hinge of the automatic document feeder has a layout that can be housed inside the automatic document feeder main body, and it is necessary to disassemble the automatic document feeder including the outer cover in order to adjust the screws. is there. For this reason, when adjustment is required at the time of factory shipment or in the market, it takes a lot of time and effort.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic document feeder capable of easily adjusting the elastic biasing force of the elastic biasing means used in the opening / closing support mechanism. Another object is to provide an image reading apparatus and an image forming apparatus.

In order to achieve the above object, the first means is that the automatic document feeder main body is attached to the attachment side via the support member so as to be freely opened and closed, and the weight of the automatic document feeder is elastically applied to the coil spring within an opening angle within a predetermined range. In the automatic document feeder that cancels out by the force and maintains the open state of the main body of the automatic document feeder,
Adjusting means for adjusting the elastic biasing force of the coil spring ;
The adjustment means
A pantograph-like expansion / contraction member that has one end substantially in contact with the end of the coil spring and expands / contracts the coil spring;
It is characterized by comprising a screw member that is screwed into the elastic member to expand and contract the elastic member .

According to a second means, in the first means, the operation end provided at the end of the screw member is provided at a position exposed to the open side when the automatic document feeder main body is opened. It is characterized by that.

According to a third means, the automatic document feeder main body is attached to the attachment side through a support member so as to be freely opened and closed, and within its predetermined opening angle, its own weight is canceled by the elastic biasing force of the coil spring. In an automatic document feeder that maintains the open state of the document feeder main body,
Adjusting means for adjusting the elastic biasing force of the coil spring;
The adjustment means
A cam member that partially abuts against the end of the coil spring and expands and contracts the coil spring according to the rotation angle;
The cam member comprises a support shaft that rotatably supports the cam member .

According to a fourth means, in the third means, the operation end provided at the end of the support shaft is provided at a position exposed to the open side when the automatic document feeder main body is opened. It is characterized by that.

The fifth means is characterized in that, in the third means, the cam of the cam member is formed by an involute curve .

A sixth means is characterized in that, in the second or fourth means, a driver groove for operation with a driver is formed at the operation end .

The seventh means is characterized in that the image reading apparatus includes an automatic document feeder according to any one of the first to sixth means, and the attached side is a main body of the image reading apparatus .

The eighth means is characterized in that the image forming apparatus includes an automatic document feeder according to any one of the first to sixth means, and the attached side is a main body of the image forming apparatus .

The ninth means is characterized in that the image forming apparatus includes the image reading apparatus according to the seventh means.

  In the embodiment described later, the main body is the ADF 300 main body, the support member is the hinge 310, the elastic biasing means is the spring 316, the screw member is the screw rod 322, the dial is the reference numeral 321 and the telescopic member is the reference numeral 325. The screw member corresponds to the screw operation shaft 324, the operation end corresponds to the reference numeral 324a, the cam corresponds to the reference numeral 327, and the driver groove corresponds to the reference numerals 324b and 327b. ,

  According to the present invention, since the elastic urging force of the elastic urging means used in the opening / closing support mechanism is provided from the direction different from the elastic urging direction of the elastic urging means, the elastic urging force is provided. The elastic biasing force of the means can be easily adjusted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic configuration diagram showing the overall configuration of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, the image forming apparatus includes a main body 100, an image reading apparatus 200 installed on the upper portion of the image forming apparatus main body 100, and an automatic document feeder (hereinafter referred to as “ADF”) mounted thereon. 300, a large-capacity paper feeding device 400 disposed on the right side in FIG. 1 of the image forming apparatus main body 100, and a sheet post-processing device 500 disposed on the left side in FIG. Has been.

  The image forming apparatus main body 100 includes an image writing unit 110, an image forming unit 120, a fixing unit 130, a duplex conveying unit 140, a sheet feeding unit 150, a vertical conveying unit 160, and a manual feeding unit 170.

  The image writing unit 110 modulates the LD, which is a light source, based on the image information of the document read by the image reading device 200, and writes laser on the photosensitive drum 121 by a scanning optical system such as a polygon mirror and an fθ lens. is there. The image forming unit includes a photoconductive drum 121 and known electrophotographic image forming elements such as a developing unit 122, a transfer unit 123, a cleaning unit 124, and a charge eliminating unit provided along the outer periphery of the photoconductive drum 121. Become.

  The fixing unit 120 fixes the image transferred by the transfer unit 123 onto the recording paper. The double-sided conveyance unit 140 is provided downstream of the fixing unit 120 in the recording paper conveyance direction, and includes a first switching claw 141 that switches the recording paper conveyance direction to the paper post-processing device 500 side or the double-sided conveyance unit 140 side. , The reverse conveying path 142 guided by the switching claw 141, the image forming side conveying path 143 that conveys the recording paper reversed by the reverse conveying path 142 to the transfer unit 123 again, and the reversed recording paper after the sheet post-processing device 500. A second switching claw 145 is disposed at a branch portion between the image forming side conveying path 143 and the post processing side conveying path 144.

  The sheet feeding unit 150 includes four sheet feeding stages. The recording sheets stored in the sheet feeding stages selected by the pickup roller and the sheet feeding roller are drawn out and guided to the vertical conveyance unit 160. The vertical transport unit 160 transports the recording paper fed from each paper feed stage to the registration roller 161 immediately upstream in the paper transport direction of the transfer unit 123, and the registration roller 161 uses the visible image on the photosensitive drum 121. The recording paper is fed into the transfer unit 123 in time with the leading edge. The manual feed unit 170 includes an openable / closable manual feed tray 171, and the manual feed tray 171 is opened as needed to supply recording paper manually. Also in this case, the recording paper is conveyed by the registration roller 161 and conveyed.

  The large-capacity paper feeder 400 stacks and supplies a large amount of recording paper of the same size, and the bottom plate 402 rises as the recording paper is consumed, so that the paper can always be picked up from the pickup roller 401. ing. The recording paper fed from the pickup roller 401 is conveyed from the vertical conveyance unit 160 to the nip of the registration roller 161.

  The sheet post-processing apparatus 500 performs predetermined processing such as punching, alignment, stapling, and sorting. In this embodiment, the punch 501, the staple tray (alignment) 502, the stapler 503, and the shift tray 504 are used for the above functions. I have. That is, the recording paper carried from the image forming apparatus 100 to the paper post-processing apparatus 500 is punched one by one with the punch 501 when punching, and then proofed if there is no particular processing. When sorting, stacking, and sorting to the tray 505, the paper is discharged to the shift tray 504. In this embodiment, the sorting is performed by the reciprocating movement of the shift tray 504 by a predetermined amount in a direction orthogonal to the sheet conveyance direction. In addition, sorting can be performed by moving the paper in a direction orthogonal to the paper transport direction on the paper transport path.

  In the case of alignment, the recording paper that has been punched or not punched is guided to the lower transport path 506, and the staple tray 504 is aligned in the direction perpendicular to the paper transport direction by the rear end fence. In the jogger fence, alignment in the direction parallel to the paper transport direction is performed. Here, when binding is performed, a predetermined position of the aligned sheet bundle, for example, a predetermined position such as a corner portion and two central positions is bound by the stapler 503 and discharged to the shift tray 504 by the discharge belt. In this embodiment, a pre-stack conveyance path 507 is provided in the lower conveyance path 506, and a plurality of sheets are stacked at the time of conveyance to avoid interruption of the image forming operation on the image forming apparatus 100 side during post-processing. Can be done.

  The image reading apparatus 200 is a known apparatus using first to third mirrors and two traveling bodies, and optically scans a document that has been guided onto the contact glass 210 and stopped, and then has first to third. A read image formed by the imaging lens through the mirror is read by a photoelectric conversion element such as a CCD. The read image data is subjected to predetermined image processing by an image processing circuit (not shown) and temporarily stored in a storage device. Then, it is read from the storage device by the image writing unit 110 at the time of image formation, modulated according to the image data as described above, and optical writing is performed.

  The ADF 300 has a double-sided reading function, and is attached to the contact glass 210 installation surface of the image reading apparatus 200 by two hinges 310 so as to be freely opened and closed, as can be seen from the attached state of FIG. FIG. 3 is an enlarged view of the ADF in FIG. The document is placed on the document table 301, and the lifting member 302 at the tip of the document table 301 presses the document against the pickup roller 303 in accordance with a reading instruction (copy instruction). Documents are pulled out from the upper surface one by one by the pickup roller 303, and are fed onto the contact glass 210 through the conveyance path 303. When the document exposed on the contact glass 210 does not need to read the back surface, the document is discharged as it is onto the discharge tray 305, and when reading the back surface, the rear end portion is a discharge roller of the reversing mechanism 306. The front end portion is sent out to the reverse tray 308 until it is sandwiched by the nip 307, and the paper discharge roller 307 is reversed to send it back onto the contact glass 210 from the reverse direction to read the back surface. The read original is discharged onto a discharge tray 305. The document on the contact glass 210 is transported by the transport belt 309.

  4 and 5 are side views showing the configuration of the hinge portion 310 of the ADF 300 according to the present embodiment. FIG. 4 shows a state in which the ADF 300 is closed, and FIG. 5 shows a state in which the hinge is opened. The ADF 300 also functions as a document pressure plate for pressing the document on the contact glass 210. When the document is read, the ADF 300 is closed as shown in FIG. 4, and when the document is placed, the maximum is usually 90 degrees. Opened. The ADF 300 has a considerable weight as described above because it includes a mechanism for automatically feeding a document, but it is 20 degrees with respect to the surface of the contact glass 210 in consideration of workability when placing the document. Contact angle between the cam surface 312a of the base 312 and the sliding surface (cam follower) 318a at the base end of the housing 318 and the elastic force of the spring 16 so that any position between 60 degrees and 60 degrees can be kept stationary. Is set.

  More specifically, in the hinge portion 310, a base 312 having an arm 311 and a cam surface 312a is supported by a support shaft 313. The support shaft 313 rotatably supports the base 312, the arm 311 is connected to the ADF 300 via the rotation shaft 314, and the base 312 is integrally formed with the image forming apparatus 100 by a screw 315. It is fixed to the upper surface of the. As described above, a spring 316 is disposed between the arm 311 and the spring 316 as an urging member for balancing with the weight of the ADF 300 when the ADF 300 is released. The spring 316 acts to widen the space between the housings 317 and 318, and one housing 317 is connected to the jack mechanism 320, and the movement position of the housing 317 is restricted. The other housing 318 is movable until it contacts the base 312. In this embodiment, two springs 316 are installed in parallel as shown in FIG.

  With such a configuration, the reason why the camera stops in an open state at any position between 20 degrees and 60 degrees (20 ° ≦ θ ≦ 60 °) is as follows. That is, the arm 311 connected to the ADF 300 in FIG. 5 freely moves clockwise (A direction in the figure) until the housing 318 attached to the arm 311 contacts the base 312 having a cam shape with the rotation shaft 313 as the center. be able to. When the housing 318 comes into contact with the base 12, the spring 316 is compressed by the shape of the cam surface 312 a of the base 312, and the arm 311 and the ADF 300 in FIG. 5 rotate counterclockwise (B direction in the figure) around the rotation shaft 313. Will occur. On the other hand, since the ADF 300 and the arm 311 attempt to rotate in the clockwise direction by their own weight, the weight of the ADF 300 and the arm 311 and the elastic biasing force of the spring 316 are balanced, and the ADF 300 can be opened and closed without applying any force to the user. it can. That is, the elastic urging force of the spring 316 and the weight of the ADF 300 cancel each other, and the stationary state can be maintained as long as the position is within the angle θ.

  When the ADF 300 having such a configuration is used for a long time, the elastic biasing force of the spring 316 is lowered due to deterioration over time, the balance cannot be achieved, and the ADF 300 cannot stop within the range of the angle θ. May occur. In order to avoid this, in this embodiment, a jack mechanism 320 as an adjustment mechanism is provided between the housing 317 and the arm 311. The jack mechanism 320 in this embodiment is a mechanism that can freely adjust the distance between the operating points, and this mechanism can be used for adjusting the spring length of the spring 316.

  Specifically, a screw rod 322 is provided in the axial direction of the spring 316, one end thereof is brought into contact with the housing 317, and the other end is arranged so as to come out to the arm 311 side. Further, a dial 321 is attached to the screw rod 322. The position of the spring 316 of the dial 321 in the axial direction is regulated by screwing. When the dial 321 is rotated by this configuration, the screw rod 322 can be moved in the axial direction. The movement of the screw rod 322 moves the housing 317 in the axial direction of the spring 316 (vertical direction in FIG. 5). The compression length of the spring can be changed. As a result, the elastic biasing force of the spring 316 changes. Therefore, if the elastic urging force of the spring 316 decreases and the ADF 300 closes due to its own weight, the compression amount of the spring 316 is increased, the elastic urging force of the spring 316 is increased, and the ADF 300 is natural in the above angle range. If the dial 321 is turned to a position where it does not fall, the adjustment of the compression amount is completed.

  In the closed position of ADF 300 in FIG. 4, the moment (clockwise moment) defined by the center of gravity of ADF 300 from the center of support shaft 313 is the moment (counterclockwise moment) generated by the drag from cam surface 312a. ), The closed state is maintained.

  FIG. 6 is an explanatory view showing a state when the dial 321 is used for adjustment. As can be seen from the figure, the elastic biasing force of the spring 316 can be easily adjusted by operating the dial 321 with a finger from the front side of the apparatus (direction orthogonal to the expansion and contraction direction of the spring 316). Since it can be easily adjusted with the fingertip in this way, when the elastic biasing force of the elastic biasing member varies during product manufacture, when the elastic biasing force changes due to long-term use in the market, or when the product is reused However, it is possible to adjust the elastic biasing force without exchanging parts using a large-scale device. Further, the dial 321 can be easily operated from the front side when the automatic document feeder 300 is opened, and thus has excellent operability.

<Second Embodiment>
7 to 9 are views for explaining the second embodiment. FIGS. 7 and 8 are side views showing the configuration of the hinge portion 310 of the ADF 300. FIG. 7 shows a state in which the ADF 300 is closed. FIG. 9 shows an opened state and FIG. 9 shows a state during adjustment.

  The second embodiment is a modification of the jack mechanism 320 in the first embodiment. In this embodiment, the combination of the screw rod 322 and the dial 321 in the first embodiment is changed to a combination of a screw operation shaft 324 and a pantograph-like expansion / contraction member (jack) 325. The jack 325 itself has a known configuration in which a screw operating shaft 324 in which a pair of screw grooves having opposite pitch directions are cut and a screwing portion 325a of an expansion / contraction member 325 are screwed into the screw grooves. A driver groove 324b is formed on the end surface of the head 324a of the screw operation shaft 324. Therefore, as shown in FIG. 9, the tip of the driver 326 is inserted into the driver groove 324 b from the front side of the apparatus (direction orthogonal to the axial direction of the spring 316), and the screw operation shaft 324 is rotated by the driver 326. The screwing position of the operation shaft 324 and the expansion / contraction member 325 is changed, and the distance between the upper end 325b and the lower end 325c of the expansion / contraction member 325 is changed by changing the angle of the pantograph-shaped leg portion with respect to the screw operation shaft 324. As a result, the compression amount of the spring 316 changes via the housing 317, and the elastic biasing force of the spring 316 can be adjusted.

  Other parts that are not particularly described are configured in the same manner as the first embodiment described above and function in the same manner, and thus redundant description is omitted.

  According to the present embodiment, the elastic urging force of the spring 316 is easily adjusted from the front side when the automatic document feeder 300 is opened by a so-called jack mechanism using the telescopic member 325 and the screw operation shaft 324. In addition, the operating force can be reduced and excellent operability can be exhibited.

<Third Embodiment>
10 to 12 are views for explaining the third embodiment. FIG. 10 is a side view showing a state in which the ADF 300 is bound, FIG. 11 is a side view showing a state in which the ADF 300 is opened, and FIG. FIG.

  The third embodiment is an example in which the jack mechanism 320 in the second embodiment is replaced with a cam mechanism. In this embodiment, the screw rod 324 and the pantograph-shaped jack 325 in the second embodiment are used as cams 327 having an involute curve so that the compression amount of the spring 316 can be changed. Specifically, as shown in FIG. 12, the cam 327 is rotatably supported integrally with the support shaft 327a, and the relative position between the holder 317 and the arm 311 that abuts the cam 327 according to the rotation angle of the cam 327. Can be changed. Since the cam has an involute curve in this way, the arm 314 and the spring 3216 are always in vertical contact with the housing 317, and only the force perpendicular to the center of the cam 327 is applied, and the cam 327 is rotated for adjustment. After that, there is no worry that the cam 327 rotates freely.

  As a result, the distance between the holder 317 and the arm 311 changes, the amount of compression of the spring 316 can be changed, and the elastic biasing force of the spring 316 can be adjusted. As in the second embodiment, the adjustment is performed by inserting the tip of the driver 326 into the driver groove 327b formed on the end surface of the support shaft 327a from the front side (direction orthogonal to the axial direction of the spring 316). 327a is rotated. As a result, the cam 327 also rotates integrally with the support shaft 327a, the amount of compression of the spring 316 can be changed, and the elastic biasing force of the spring 316 can be adjusted.

  Other parts that are not particularly described are configured in the same way as the first and second embodiments described above and function in the same way, and thus redundant description is omitted.

  According to the present embodiment, since the elastic biasing force of the spring 316 is adjusted by the cam, the automatic document feeder 300 can be adjusted from a direction perpendicular to the elastic biasing direction of the elastic biasing means. When the is opened, it can be easily operated from the front side. Further, since the mechanism using the cam simplifies the whole mechanism, the cost can be reduced. Further, since the cam is configured with an involute curve, even if the cam is rotated, only a force perpendicular to the cam center acts, and no force in the rotational direction acts on the cam. As a result, the cam does not rotate arbitrarily, and there is no possibility of shifting after adjustment.

1 is a schematic configuration diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the attachment state with respect to the image reading apparatus of ADF. It is a figure which shows schematic structure of ADF. It is a side view which shows the structure of the hinge part of ADF which concerns on 1st Embodiment, and shows the state which closed ADF. It is a side view which shows the structure of the hinge part of ADF which concerns on 1st Embodiment, and shows the state which open | released ADF. It is explanatory drawing which shows a state when adjusting the elastic urging | biasing force of a spring using a dial in 1st Embodiment. It is a side view which shows the structure of the hinge part of ADF which concerns on 2nd Embodiment, and shows the state which closed ADF. It is a side view which shows the structure of the hinge part of ADF which concerns on 2nd Embodiment, and shows the state which open | released ADF. It is explanatory drawing which shows a state when adjusting the elastic urging | biasing force of a spring using a driver in 2nd Embodiment. It is a side view which shows the structure of the hinge part of ADF which concerns on 3rd Embodiment, and shows the state which closed ADF. It is a side view which shows the structure of the hinge part of ADF which concerns on 3rd Embodiment, and shows the state which open | released ADF. It is a front view of FIG.

Explanation of symbols

100 Image forming apparatus 200 Image reading apparatus 300 Automatic document feeder (ADF)
310 Hinge 316 Spring 321 Dial 322 Screw rod 324 Screw operation shaft 324a Operation end 324b, 327b Driver groove 325 Telescopic member 326 Driver 327 Cam

Claims (9)

Automatic document feeder main body portion via a supporting member openably mounted to the mounting side, the weight is within the opening angle of the predetermined range is offset by the elastic biasing force of the coil spring, the automatic original feeding apparatus main body In an automatic document feeder that maintains the open state of
Adjusting means for adjusting the elastic biasing force of the coil spring ;
The adjustment means
A pantograph-like elastic member that has one end substantially in contact with the end of the coil spring and expands and contracts the coil spring;
An automatic document feeder comprising a screw member that is screwed into the elastic member to expand and contract the elastic member . 2. The automatic document according to claim 1 , wherein an operation end provided at an end portion of the screw member is provided at a position exposed to an open side when the automatic document feeder main body is opened. Feeding device. The automatic document feeder main body is attached to the attachment side through a support member so as to be freely opened and closed, and within its predetermined opening angle, its own weight is canceled by the elastic biasing force of the coil spring. In an automatic document feeder that maintains the open state of
Adjusting means for adjusting the elastic biasing force of the coil spring;
The adjustment means
A cam member that partially abuts against the end of the coil spring and expands and contracts the coil spring according to the rotation angle;
An automatic document feeder comprising a support shaft for rotatably supporting the cam member . 4. The automatic document according to claim 3 , wherein an operation end provided at an end of the support shaft is provided at a position exposed to an open side when the automatic document feeder main body is opened. Feeding device. 4. The automatic document feeder according to claim 3, wherein the cam of the cam member is formed by an involute curve . 5. The automatic document feeder according to claim 2, wherein a driver groove for operation by a driver is formed at the operation end . An image reading apparatus comprising the automatic document feeder according to any one of claims 1 to 6, wherein the attached side is an image reading apparatus main body. An image forming apparatus comprising the automatic document feeder according to claim 1, wherein the attached side is an image forming apparatus main body. An image forming apparatus comprising the image reading apparatus according to claim 7.

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