JP2011232560A - Opening/closing unit and image forming apparatus provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an opening/closing unit with a grounding spring in a torsion coil form that is applicable to any type of the unit, having a simple structure to prevent the grounding spring from coming off the unit.SOLUTION: The opening/closing unit is configured such that a unit body is openably/closably supported to a base by means of a fulcrum pin 32. In this opening/closing unit, a grounding spring 34 in a torsion coil form is attached to the opening/closing support pin 32 so as to urge the unit body in an opening direction, in such a setting: an inner diameter of the grounding spring in assembling≥an outer diameter of the fulcrum pin>an inner diameter of the grounding spring in use>an outer diameter of a groove portion of the fulcrum pin, as well as in such a setting: a grounding contact load in use>a grounding contact load in assembling.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opening / closing unit formed by supporting a unit body so as to be openable / closable with respect to a base by a fulcrum pin, and an image forming apparatus including the opening / closing unit.

  For example, an image forming apparatus such as a copying machine that forms an image on a sheet by an electrophotographic method is provided with an image reading apparatus for optically reading a document image. This image reading apparatus performs maintenance or the like. The unit main body is supported so as to be openable and closable with respect to the base. Specifically, one end of the unit main body is rotatably supported on the base by a fulcrum pin. This main body unit is closed during use, and the main unit is not used when maintenance is required. be opened.

  By the way, the main unit is always urged in the opening direction by a torsion coil coil spring attached to the fulcrum pin, but the torsion coil spring also has a function as an earth spring.

  A torsion coil spring is generally used for an open / close unit (see, for example, Patent Document 1). When this torsion coil spring is attached, the torsion coil spring is sandwiched between two members to prevent the coil coil spring from being pulled out, or hooked on the torsion coil spring. Techniques such as providing shapes have been adopted, and when these techniques cannot be employed, the use of torsion coil springs has been abandoned.

JP 2002-021424 A

  As in the past, it is not possible for all devices to adopt a configuration in which a torsion coil spring is sandwiched between two members to prevent it from falling out, or a hook shape is provided on the torsion coil spring. In addition, there is a problem in that such a method for preventing omission leads to a complicated structure.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is an opening / closing unit that can apply a torsion coil-like earth spring to all of them regardless of the model and prevent the disconnection with a simple configuration. The present invention provides an image forming apparatus including the above.

In order to achieve the above object, an invention according to claim 1 is an open / close unit comprising a unit body supported by a fulcrum pin so as to be openable and closable.
A torsion coil-shaped earth spring that urges the body unit in the opening direction is attached to the opening / closing support pin,
Earth spring inner diameter during assembly ≧ fulcrum pin outer diameter> earth spring inner diameter during use> fulcrum pin groove outer diameter.

The invention according to claim 2 is the invention according to claim 1,
It is characterized in that the ground contact load at the time of use> the ground contact load at the time of assembly is set.

  An image forming apparatus according to a third aspect includes the opening / closing unit according to the first or second aspect.

  According to the present invention, since the inner diameter of the ground spring at the time of assembly is set to be greater than or equal to the outer diameter of the fulcrum pin, the ground spring can be easily passed through the fulcrum pin and incorporated. When the open / close unit is used, the unit main body is turned around the fulcrum pin and closed, but the ground spring is reduced in diameter by the operation of closing the unit main body, and the inner diameter becomes smaller than the outer diameter of the support pin. Since it is tightened to the outer periphery of the groove portion, the ground spring is reliably prevented from coming off from the fulcrum pin, and the conductive ground spring and the fulcrum pin are connected to each other so that the main unit is securely grounded. In this way, the earth spring can be used for any opening / closing unit because it has a simple configuration that allows it to pass through the fulcrum pin, reduces the diameter by the closing operation of the main body unit, prevents its removal, and performs the earth function. .

  In addition, since the earth contact load at the time of use is set larger than the earth contact load at the time of assembly, the earthing at the time of use is surely performed.

1 is a cross-sectional view of a color image forming apparatus as an embodiment of an image forming apparatus according to the present invention. (A)-(c) is a side view which shows opening and closing of the image reading apparatus as one form of the opening / closing unit which concerns on this invention. It is the A section enlarged detail drawing of FIG.2 (c). (A) is a front view of the earth spring and fulcrum pin at the time of assembly, (b) is a sectional view taken along line BB of (a). (A) is a front view of the earth spring and fulcrum pin at the time of use, (b) is CC sectional view taken on the line of (a).

Embodiments of the present invention will be described below with reference to the accompanying drawings.
[Image forming apparatus]
FIG. 1 is a cross-sectional view of a color image forming apparatus according to the present invention. The illustrated color image forming apparatus is a color complex machine having a copying function, a printer function, and a facsimile function, and has a rectangular box-shaped apparatus main body 100. An image reading device 30 is disposed on the upper portion of the image reader, and an automatic document feeder (ADF) 50 is provided on the upper portion of the image reading device 30. A paper discharge tray 20 that opens toward the front is provided between the apparatus main body 100 and the image reading apparatus 30.

  Next, the internal structure of the apparatus main body 100 will be described below.

  In the central portion of the apparatus main body 100, a magenta image forming unit 1M, a cyan image forming unit 1C, a yellow image forming unit 1Y, and a black image forming unit 1K are arranged in tandem in the front-rear direction at regular intervals.

  Each of the image forming units 1M, 1C, 1Y, and 1K is provided with photosensitive drums 2a, 2b, 2c, and 2d, which are image carriers, and a charger 3a is disposed around each of the photosensitive drums 2a to 2d. 3b, 3c, 3d, developing devices 4a, 4b, 4c, 4d, primary transfer rollers 5a, 5b, 5c, 5d and drum cleaning devices 6a, 6b, 6c, 6d, respectively.

  Here, the photosensitive drums 2a to 2d are drum-shaped photosensitive members, and are driven to rotate at a predetermined process speed in a direction indicated by an arrow (clockwise) by a driving motor (not shown). The chargers 3a to 3d charge the surfaces of the photosensitive drums 2a to 2d uniformly to a predetermined potential by a charging voltage applied thereto.

  Further, the developing devices 4a to 4d contain magenta (M) toner, cyan (C) toner, yellow (Y) toner, and black (K) toner, respectively, and are formed on the photosensitive drums 2a to 2d. In addition, the toner of each color is attached to each electrostatic latent image, and each electrostatic latent image is visualized as a toner image of each color.

  The primary transfer rollers 5a to 5d are disposed so as to be in contact with the photosensitive drums 2a to 2d via an endless intermediate transfer belt 7 which is an intermediate transfer member at each primary transfer portion. Here, the intermediate transfer belt 7 is stretched in the front-rear direction between a driving roller 8 disposed on the side and a tension roller 9 disposed on the front side, and each of the photosensitive belts below the intermediate transfer belt. The drums 2a to 2d are arranged in tandem along the front-rear direction. The drive roller 8 is disposed so as to be able to contact the secondary transfer roller 10 via the intermediate transfer belt 7 in the secondary transfer portion, and a belt cleaning device 11 is provided in the vicinity of the tension roller 9. Yes.

  Further, a laser scanner unit (LSU) 12 is disposed below the image forming units 1M, 1C, 1Y, and 1K in the apparatus main body 100, and a paper feed cassette 13 is detachably attached to the bottom of the main body 100 below the image forming units. is set up. A plurality of sheets of paper (not shown) are stacked and stored in the paper feed cassette 13. In the vicinity of the paper feed cassette 13, a pickup roller 14 that picks up paper from the paper feed cassette 13, and the picked up paper are placed. A feed roller 15 and a retard roller 16 are provided that are separated and fed one by one to the transport path S1.

  On the other hand, above the intermediate transfer belt 7 in the apparatus main body 100, toner containers 17a, 17b, 17c, respectively containing magenta, cyan, yellow, and black toners to be supplied to the developing devices 4a to 4d, respectively. 17d is arrange | positioned along the front-back direction.

  By the way, the conveyance path S1 is arranged substantially vertically on the back side of the apparatus main body 100, and another conveyance path S2 used for forming images on both sides of the sheet is arranged substantially vertically on the inside. Has been. The transport paths S1 and S2 communicate with each other in the vertical direction, and a flapper 18 is rotatably provided at a location where the transport paths S1 and S2 communicate with each other in the upper part.

  Here, the transport path S1 is a secondary portion which is a contact portion between the secondary transfer roller 10 and the intermediate transfer belt 7 at a predetermined timing after the paper supplied from the paper feed cassette 13 is temporarily held. A registration roller pair 19 is provided to be supplied to the transfer unit. A fixing device 21, a transport roller pair 22, and a paper discharge roller pair 23 are provided at portions extending upward from the secondary transfer portion of the transport path S 1 to the paper discharge tray 20. In addition, a plurality of reversing roller pairs 24 are provided at appropriate intervals in the conveyance path S2 used when images are formed on both sides.

  Further, a manual feed tray 25 is provided on the front surface of the apparatus main body 100 so as to be openable and closable. A conveyance path S3 extends substantially horizontally from the manual feed tray 25 toward the back side, and an end of the conveyance tray S3 It joins the road S1. A feed roller 26 and a plurality of transport roller pairs 27 are provided in the transport path S3.

  Next, an image forming operation by the color image forming apparatus having the above configuration will be described.

  When the image formation start signal is issued, for example, an original document that has been sent by the automatic document feeder 50 onto the document table of the image reading device 30 is read by the image reading device 30, and the read image data is the laser scanner unit 12. Stored in the memory.

  On the other hand, in each of the image forming units 1M, 1C, 1Y, and 1K, the photosensitive drums 2a to 2d are rotationally driven at a predetermined process speed in the direction of the arrow (clockwise) in the drawing, and the photosensitive drums 2a to 2d are charged by the charger 3a. It is uniformly charged by ~ 3d. The laser scanner unit 12 emits a laser beam modulated by a color image signal for each color based on the image data stored in the memory, and irradiates the surface of the photosensitive drums 2a to 2d with the laser beam. An electrostatic latent image corresponding to each color image signal is formed on each of the photosensitive drums 2a to 2d.

  First, magenta toner is attached to the electrostatic latent image formed on the photosensitive drum 2a of the magenta image forming unit 1M by the developing device 4a to which a developing bias having the same polarity as the charged polarity of the photosensitive drum 2a is applied. The electrostatic latent image is visualized as a magenta toner image. This magenta toner image is shown in the figure by the action of the transfer roller 5a to which a primary transfer bias having a polarity opposite to that of the toner is applied in the primary transfer portion (transfer nip portion) between the photosensitive drum 2a and the transfer roller 5a. Primary transfer is performed on the intermediate transfer belt 7 that is rotationally driven in the direction.

  The intermediate transfer belt 7 on which the magenta toner image has been primarily transferred as described above moves to the next cyan image forming unit 1C. Also in the cyan image forming unit 1C, similarly to the above, the cyan toner image formed on the photosensitive drum 2b is transferred to the magenta toner image on the intermediate transfer belt 7 at the primary transfer portion.

  Similarly, yellow and black toners respectively formed on the photosensitive drums 2c and 2d of the yellow and black image forming units 1Y and 1K on the magenta and cyan toner images superimposed and transferred on the intermediate transfer belt 7, respectively. The images are sequentially superimposed on each primary transfer portion, and a full-color toner image is formed on the intermediate transfer belt 7. The transfer residual toner which is not transferred onto the intermediate transfer belt 7 and remains on the photosensitive drums 2a to 2d is removed by the drum cleaning devices 6a to 6d, and the photosensitive drums 2a to 2d are prepared for the next image formation. It is done.

  Then, the pickup roller 14 from the paper feed cassette 13 is synchronized with the timing when the leading end of the full color toner image on the intermediate transfer belt 7 reaches the secondary transfer portion (transfer nip portion) between the intermediate transfer belt 7 and the secondary transfer roller 10. The sheet fed to the transport path S1 by the feed roller 15 and the retard roller 16 is transported to the secondary transfer portion by the registration roller pair 19. Then, a full-color toner image is collectively transferred from the intermediate transfer belt 7 onto the sheet conveyed to the secondary transfer unit by the secondary transfer roller 10 to which a secondary transfer bias having a polarity opposite to that of the toner is applied. .

  Thus, the sheet on which the full-color toner image has been transferred is conveyed to the fixing device 21, and the full-color toner image is heated and pressurized and fixed on the surface of the sheet. A pair of conveying rollers 22 and a pair of paper discharge rollers 23 are discharged from the back side toward the front side on the paper discharge tray 20 to complete a series of image forming operations. The transfer residual toner that is not transferred onto the sheet and remains on the intermediate transfer belt 7 is removed by the belt cleaning device 11, and the intermediate transfer belt 7 is prepared for the next image formation. Further, when an image is formed on one side of the paper in this way, the flapper 18 is at a position indicated by a solid line in FIG.

  The above is the image forming operation by cassette feeding. When an image is manually formed on the paper, the manual tray 25 is opened as shown in FIG. 1 and the paper is supplied from the opened manual tray 25. Then, the sheet is sent out to the transport path S3 by the feed roller 26, transported through the transport path S3 by the plurality of transport roller pairs 27, and delivered to the transport path S1, and thereafter the same as described above. Through this process, an image is formed on one side.

Further, when images are formed on both sides of a sheet, the flapper 18 is switched as shown by a broken line in FIG. 1 immediately before the sheet having an image formed on one side through the above process is discharged to the sheet discharge tray 20. At the same time, the paper discharge roller pair 23 is reversed and the paper is switched back to the transport path S2. Then, the sheet is conveyed downward along the conveyance path S2 by the pair of reversing rollers 24 and is transferred to the conveyance path S1, and then an image is formed on the opposite surface (back surface) through the same process as described above. Then, the paper on which the images are formed on both sides is discharged from the back side toward the front side by the paper discharge roller pair 23 to the paper discharge tray 20. At this time, the flapper 18 is returned to the position indicated by the solid line in FIG.
[Opening and closing unit]
Next, an embodiment of the image reading device 30 which is an embodiment of the opening / closing unit according to the present invention will be described.

  2A to 2C are side views showing opening and closing of the image reading apparatus, FIG. 3 is an enlarged detail view of a part A in FIG. 2C, and FIG. 4A is a front view of the ground spring and the fulcrum pin during assembly. 4 (b) is a cross-sectional view taken along the line BB of FIG. 4 (a), FIG. 5 (a) is a front view of the ground spring and the fulcrum pin in use, and FIG. 5 (b) is a cross-sectional view of FIG. FIG.

  As shown in FIG. 2, the image reading apparatus 30 is configured by supporting a unit main body 31 so as to be openable and closable with respect to a base 33 by a fulcrum pin 32, and the unit main body 31 is a twist attached to the fulcrum pin 32. The coil-shaped earth spring 34 is always urged in the opening direction. Although not shown, an optical system carriage provided with a light source, a reflecting mirror, and the like is accommodated in the main unit 31 so as to be reciprocable in the sub-scanning direction (left-right direction in FIG. 2).

  Here, both the fulcrum pin 32 and the earth spring 34 are made of a conductive metal. As shown in FIG. 3, the earth spring 34 is wound around a small-diameter groove 32a formed at the axial end of the fulcrum pin 32. One end 34 a of both ends 34 a and 34 b (see FIGS. 4 and 5) extending linearly is locked to the main unit 31, and the other end 34 b is locked to the base 33. The ground spring 34 also has a function of grounding the main unit 31, and serves to release static electricity generated in the main unit 31 to the outside through the fulcrum pin 32 and the base 33.

  Thus, when the image reading apparatus 30 is used, the main unit 31 is closed as shown in FIG. 2A, and the closed state of the main unit 31 is held by a lock mechanism (not shown).

  When maintenance or the like is required for the image reading device 30, the main unit 31 is rotated and opened by the illustrated angle about the fulcrum pin 32 as shown in FIG. At this time, since the main unit 31 is urged in the opening direction by the ground spring 34, the opening operation of the main unit 31 is easily performed, and the main unit 31 is moved to the position shown in FIG. The angle shown in FIG.

  When the ground spring 34 is attached to the fulcrum pin 32 at the time of assembly, the main unit 31 is rotated by an angle of about 90 ° about the fulcrum pin 32 and is erected substantially vertically as shown in FIG. The

  Thus, as shown in FIG. 2 (c), the ground spring 34 is attached to the fulcrum pin 32 with the main body unit 31 standing substantially vertically, but in this embodiment, as shown in FIGS. The following relationship is established between the inner diameter d of the ground spring 34 during assembly, the inner diameter d ′ of the ground spring 34 during use, the outer diameter D1 of the fulcrum pin 32, and the outer diameter D2 of the groove 32a of the fulcrum pin 32. ing.

d ≧ D1> d ′> D2 (1)
As described above, since the inner diameter d of the ground spring 34 at the time of assembly is set to the outer diameter D1 ≧ of the fulcrum pin 32, the ground spring 34 is easily passed through the fulcrum pin 32 as shown in FIG. 34 is fitted into the groove 32 a of the fulcrum pin 32. At this time, as described above (see equation (1)), the inner diameter d of the ground spring 34 when assembled is larger than the outer diameter D2 of the groove 32a of the fulcrum pin 32 (d> D2). As shown, a radial gap δ (= (d−D2) / 2) is generated between the ground spring 34 and the groove 32a of the fulcrum pin 32.

  Thus, the main body unit 31 is rotated around the fulcrum pin 32 from the state shown in FIG. 2C in which the ground spring 34 is passed through the fulcrum pin 32 and fitted into the groove 32a of the fulcrum pin 32 as described above. When closed as shown in FIG. 2 (a), the linear one end 34a of the ground spring 34 locked to the main unit 31 is rotated from the position shown by the broken line to the position shown by the solid line in FIG. 5 (b). Therefore, the earth spring 34 is reduced in diameter as shown in FIG. 5, and its inner diameter is reduced from d to d ′ (d ′ <d). Here, as shown in the equation (1), since the inner diameter d ′ of the ground spring 34 in use (in a state where the opening / closing unit 31 is closed) is smaller than the outer diameter D1 of the fulcrum pin 32 (d ′ <D1), Even when the ground spring 34 does not come off the fulcrum pin 32 and the main body unit 31 is opened by a predetermined angle for maintenance or the like as shown in FIG. Since the state smaller than the diameter D1 (d ′ <D1) is maintained, the ground spring 34 does not come off from the fulcrum pin 32 during use.

  As shown in FIG. 2A, when the main unit 31 is closed, the ground spring 34 having a reduced diameter is fastened to the outer periphery of the groove portion 32a of the fulcrum pin 32, so that the conductive ground spring 34 and the fulcrum pin 32 are connected to each other. It becomes conductive and the main unit 31 is securely grounded. In particular, in the present embodiment, as shown in FIG. 2A, the load (ground contact load) P1 acting on the ground spring 34 when the main unit 31 is closed as shown in FIG. Since the load is greater than the load P2 (ground contact load) P2 acting on the ground spring 34 when the unit 31 is erected substantially vertically (P1> P2), the main unit 31 is reliably grounded during use.

  As described above, in the present embodiment, the earth spring 34 has a simple configuration that is simply passed through the fulcrum pin 32, and the diameter of the earth spring 34 is reduced by the closing operation of the main body unit 31 to prevent the earth spring 34 from being pulled out. Therefore, the image reading apparatus 30 can be used regardless of the model of the image reading apparatus 30 or any other arbitrary opening / closing unit.

  Although the present invention has been described with respect to an embodiment in which the present invention is applied to a color image forming apparatus and an image reading apparatus provided in the color image forming apparatus, the present invention is not limited to other arbitrary image forming such as a color copying machine and a monochrome copying machine. Of course, the present invention can be similarly applied to the apparatus and the image reading apparatus provided in the apparatus or other opening / closing units.

1M Magenta image forming unit 1C Cyan image forming unit 1Y Yellow image forming unit 1K Black image forming unit 2a to 2d Photosensitive drum 3a to 3d Charger 4a to 4d Developing device 5a to 5d Transfer roller 6a to 6d Drum cleaning device 7 Intermediate transfer belt 8 Driving roller 9 Tension roller 10 Secondary transfer roller 11 Belt cleaning device 12 Laser scanner unit (LSU)
DESCRIPTION OF SYMBOLS 13 Paper feed cassette 14 Pickup roller 15 Feed roller 16 Retard roller 17a-17d Toner container 18 Flapper 19 Registration roller pair 20 Paper discharge tray 21 Fixing device 22 Transport roller pair 23 Paper discharge roller pair 24 Reverse roller pair 25 Manual feed tray 26 Feed roller 27 Conveying roller pair 30 Image reading device (open / close unit)
31 Body Unit 32 Supporting Pin 32a Groove of Supporting Pin 33 Base 34 Ground Spring 34a, 34b End of Earth Spring 50 Automatic Document Feeder (ADF)
100 Image forming apparatus main body D1 Outer diameter of fulcrum pin D2 Outer diameter of fulcrum pin groove part d Inner diameter when assembling earth spring d 'Inner diameter when using earth spring S1 to S3 Conveying path δ Inner diameter of earth spring and fulcrum pin groove part when assembling Gap between

Claims (3)

In the opening / closing unit that supports the unit body so that it can be opened and closed with respect to the base by a fulcrum pin,
A torsion coil-shaped earth spring that urges the body unit in the opening direction is attached to the opening / closing support pin,
Opening / closing unit characterized in that ground spring inner diameter during assembly ≧ fulcrum pin outer diameter> ground spring inner diameter during use> fulcrum pin groove outer diameter. 2. The switching unit according to claim 1, wherein the ground contact load during use is set to be greater than the ground contact load during assembly.   An image forming apparatus comprising the opening / closing unit according to claim 1.

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