JP3104053B2 - Transfer device of image forming machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device mounted on an image forming machine such as an electrophotographic device or an electrostatic recording device, and more particularly, to transfer a toner image formed on an image carrier to transfer paper. Further, the present invention relates to a transfer device of an image forming machine that conveys a transfer sheet on which a toner image has been transferred.

[0002]

2. Description of the Related Art In this type of image forming apparatus, a transfer method using corona discharge is generally used as a method for transferring a toner image formed on an image carrier to transfer paper. However,
The transfer method using the corona discharge has a problem in that transferability at high humidity is poor, and transfer failure easily occurs due to dirt on corona wires, wrinkles of transfer paper, and the like. As a means for solving such a problem, a driving roller, a driven roller disposed at a distance from the driving roller, a transfer belt stretched between the driving roller and the driven roller, A transfer belt unit including a transfer roller disposed opposite to the image carrier with the transfer belt interposed therebetween is disposed opposite the image carrier, and a high voltage is applied to the transfer roller to transfer the transfer belt. Is charged to a predetermined polarity so that a toner image formed on the surface of the image carrier is sequentially sucked and transferred to the transfer paper supplied between the image carrier and the transfer belt. For example, it is disclosed in JP-A-4-345183. In such a transfer method, a voltage can be applied at a transfer point, and the transfer paper is sandwiched between transfer rollers via an image carrier and a transfer belt. Can be

[0003]

Since the transfer belt is easily deformed or deteriorates at an early stage when the transfer belt is pressed against the image carrier even during non-transfer, the transfer belt unit is used during non-transfer. It is constituted so that it may be separated from. However, even when the transfer belt unit is operated at a position separated from the image carrier, the transfer roller disposed opposite to the image carrier with the transfer belt interposed therebetween comes into contact with the transfer belt and is pressed against the transfer belt by the tension of the transfer belt. It has a configuration that has been. If the transfer belt is constantly pressed against the transfer roller, the transfer roller is deformed and causes transfer failure. There is not much effect when the transfer roller is made of a relatively hard material such as hard rubber.However, when the transfer roller is made of a soft material such as sponge rubber or urethane foam, the transfer belt is significantly deformed due to pressure contact. appear.

The present invention has been made in view of the above points, and its main technical problem is that a transfer roller is pressed against an image carrier via a transfer belt during transfer, and the transfer belt is pressed against the image carrier during non-transfer. It is an object of the present invention to provide a transfer device of an image forming machine capable of separating a transfer roller from a transfer belt while separating the transfer roller from the transfer belt. Other technical problems and features of the present invention will be clarified by the following description.

[0005]

According to the present invention, there is provided a driving roller, a driven roller disposed at a distance from the driving roller, and a driving roller. A belt unit having a transfer belt stretched between the driven roller and the driven roller, and a transfer roller disposed opposite to the image carrier with the transfer belt interposed therebetween; and A transfer means for operating the transfer roller at a non-transfer position; and a voltage applying means for applying a predetermined voltage to the transfer roller, and a copy paper supplied between the transfer belt and the image carrier is provided on the image carrier. In a transfer device of an image forming machine that transfers a formed toner image and conveys a transfer sheet on which the toner image has been transferred, the transfer roller is disposed apart from the transfer belt, and the contact / separation means The belt unit is transferred by Positioned location when the transfer roller is configured to press the said transfer belt to the image carrier, a transfer device of an image forming apparatus is provided, characterized in that.

[0006]

In the transfer device of the image forming apparatus according to the present invention, when the belt unit is positioned at the transfer position by the contact / separation means at the time of transfer, the transfer roller presses the transfer belt against the image carrier and at the time of non-transfer, the belt is moved by the contact / separation means. When the unit is located at the non-transfer position, the transfer belt is separated from the image carrier and the transfer roller is separated from the transfer belt.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a transfer device of an image forming apparatus according to a preferred embodiment of the present invention;

FIG. 1 is a schematic structural view showing an embodiment of an image forming machine equipped with a transfer device according to the present invention, and FIG. 2 is a front view of the image forming machine equipped with a transfer device according to the present invention.

The image forming machine 2 shown in FIG. 1 has an image carrier 3 composed of a photosensitive drum rotatably mounted. Around the image carrier 3, a charging corona discharger 4, a developing device 5,
A transfer device 6, a cleaning unit 7, and a charge removing lamp 8 configured according to the present invention are provided. The illustrated image forming machine 2 includes an irradiation lamp 9, a first mirror 10, a second mirror 11, a third mirror 12, a lens 13, and a fourth mirror 14 disposed above the image carrier 3. Is provided. This optical system includes an irradiation lamp 9
Irradiates a document placed on a document placing transparent plate (not shown) with the first mirror 10, the second mirror 11, the third mirror 12, the lens 13, and the fourth mirror 14 with the reflected light image. It is configured to form an image on the image carrier 3 through the above. The image forming machine 2 includes a transfer paper supply device 15 for supplying transfer paper to the transfer device 6.
The transfer paper supply device 15 includes a transfer paper cassette 16 for storing transfer paper, a transfer paper feed roller 17, a paper feed roller pair 18,
A guide path 19, a conveying roller pair 20, a guide path 21, and a registration roller pair 22 are provided. A pair of fixing rollers 23 and a pair of discharge rollers 24 are provided on the transfer paper sending side of the transfer device 6. In the image forming apparatus configured as described above, each member disposed below the one-dot chain line in FIG. 1 is disposed in the lower housing 25 constituting the clamshell type body housing illustrated in FIG. In FIG. 1, each member disposed above the one-dot chain line is disposed in the upper housing 26. The upper housing 26
The lower right end in FIG.
7 so as to be pivotable. Transfer device 6
Is a lower housing 2 as shown by a two-dot chain line in FIG.
5 is disposed at the center. An opening 28 for mounting the transfer paper cassette 16 is formed in a front plate of the lower housing 25.

The image forming apparatus 2 configured as described above
While the image carrier 3 is driven to rotate in the direction of arrow A,
The charging corona discharger 4 substantially uniformly charges the photoreceptor on the image carrier 3 to a specific polarity, and then irradiates the original placed on a not-shown original placing transparent plate by an irradiation lamp 9, The reflected light image is the first mirror 10 and the second mirror 1
Scanning exposure is performed on the image carrier 3 via the first, third mirror 12, lens 13 and fourth mirror 14, and an electrostatic latent image is formed on the image carrier 3. Thereafter, the image carrier 3
The upper electrostatic latent image is developed into a toner image by the developing device 5. On the other hand, the transfer paper stored in the transfer paper cassette 16 of the transfer paper supply device 15 is sent out from the transfer paper sending roller 17, and the paper feed roller pair 18, the guide path 19, the transport roller pair 2
0, the sheet is conveyed to the transfer device 6 through the guide path 21 and the registration roller pair 22. The transfer paper conveyed to the transfer device 6 is transferred between the image carrier 3 on which the toner image is formed and a transfer belt of the transfer device 6 described later, so that the toner image is transferred, and then fixed by the fixing roller pair 23. Then, the sheet is discharged from the discharge roller pair 24. Further, the toner adhered to the surface of the photoreceptor is removed from the image bearing member 3 having undergone the transfer process as described above by the cleaning unit 7, and further, the discharging lamp 8 irradiates the surface of the photoreceptor with discharging light. And the charge is removed.

Next, the transfer device 6 will be described with reference to FIGS. 3 is a perspective view of a transfer belt unit constituting the transfer device, FIG. 4 is a plan view of the transfer belt unit, FIG. 5 is a front view showing a part of the transfer belt unit cut away, and FIG. 6 is a cross section of the transfer belt unit. FIG. The illustrated transfer belt unit 29 includes a belt unit 30 and a unit housing 60 that stores and supports the belt unit 30.

The belt unit 30 will be described mainly with reference to FIGS. 7, 8 and 9. The illustrated belt unit 30 includes a support frame 31 as clearly shown in FIG. This support frame 31
Has a base 32 and end walls 33 and 34 formed at the front end and the rear end of the base 32, respectively, and these are integrally formed of synthetic resin. End walls 33 and 3
4 have cutouts 331, 332, 333 that open upward.
And 341, 342, 343 are formed respectively.
Support plates 35 and 36 formed of a synthetic resin for supporting each roller described later are provided on the end walls 33 and 34.
Are attached by screws 37, 38 (only the support plate 36 side is shown in FIG. 7). Cylindrical stoppers 351 and 361 projecting forward (upper left in FIG. 7) and rear (lower right in FIG. 7) are formed integrally at the center of the support plates 35 and 36, respectively. The stoppers 351 and 361 have a function of defining the positional relationship between the belt unit 30 and the image carrier 3 by contacting the lower surface of the holder that rotatably supports the image carrier 3. Further, support plates 39 and 40 formed of a synthetic resin for supporting a drive roller described later are mounted on the end walls 33 and 34 of the support frame 31. The support plates 39 and 40 are rotatably connected at the ends of the support plates 35 and 36 by pins 41 (only the support plate 40 side is shown in FIG. 7).
It is fixed by screws 42 (only the support plate 36 is shown in FIG. 7). The mounting portions 391 and 401 on the disk are provided on the outer surfaces of the support plates 39 and 40.
Are provided, and the mounting portions 391 and 401
Have two surfaces 392, 392 and 4 each parallel to its outer periphery
02 and 402 are formed (see FIG. 4).

A drive roller 43 is provided between the support plates 39 and 40. The drive roller 43 is provided as shown in FIG.
As shown in FIG. 8, the shaft is formed of a hollow material made of an aluminum alloy, and rotation shafts 431 and 432 are attached to a front end (left end in FIG. 8) and a rear end (right end in FIG. 8). The front rotating shaft 431 is rotatably supported by a bearing 44 disposed on the support plate 39. A gear 45 is mounted on the front rotation shaft 431, and the gear 45 is formed with an engagement groove 45 formed on a side surface thereof.
1 is a pin 4 disposed radially through the rotation shaft 431.
52 is configured to rotate integrally with the rotation shaft 431 by engaging with the rotation shaft 431. At the front end of the rotating shaft 431, a detachable member 46 having holes 461 and 462 for inserting mounting bolts is rotatably mounted. The attachment / detachment member 46 is provided with a position regulating means 465 including a guide portion 463 having a conical surface and a fitting portion 464 formed continuously on the outer periphery of the guide portion 463. The function of the detachable member 46 thus configured will be described later.
The rear rotating shaft 432 is rotatably supported by a bearing 441 disposed on the support plate 40. A position regulating member 47 is rotatably mounted on the rear rotating shaft 432, and the position regulating member 47 is pressed rightward in FIG. 8 by a coil spring 475 disposed between the position regulating member 47 and the mounting portion 401. Have been. The position regulating member 47 includes a guide portion 471 having a conical surface, a fitting portion 472 formed continuously on the outer periphery of the guide portion 471, and a flange portion 473. The function of the position regulating member 47 thus configured will be described later. A driven gear 48 is mounted on the rear rotating shaft 432, and the gear 48 has a pin provided with an engaging groove 481 formed on a side surface thereof and penetrating the rotating shaft 432 in the radial direction. 482 is configured to rotate integrally with the rotation shaft 432.

A driven roller 49, a transfer roller 50, a tension roller 51, and an earth roller 52 are disposed between the support plates 35 and 36. Note that the support structure of the respective rollers on the support plate 35 side and the support plate 36 side support structure are the same in the illustrated embodiment, and therefore only the support plate 36 side support structure is shown in FIG.

The driven roller 49 is formed of a columnar material made of an aluminum alloy, and has a rotating shaft 491 whose both ends are reduced in diameter. The rotating shaft 491 is mounted on the support plate 36 (35). The bearing 53 is rotatably supported by a bearing 53.

The transfer roller 50 includes a rotating shaft 501 formed of a cylindrical material made of steel and a sponge-shaped roller portion 502 mounted on the outer peripheral surface of the rotating shaft 501 with a conductive adhesive. (See FIG. 6). The roller section 502 is formed by impregnating a roll member formed of a foam such as urethane foam or silicone foam with a powder of a conductive substance such as carbon, and has a volume electric resistance value of 10 ² to 10 ⁹ Ωcm. Is set to As a method of impregnating the conductive material into the roll member constituting the roller portion 502, for example, a foam material such as urethane foam or silicone foam is formed in a solution obtained by dissolving a powder of a conductive material such as carbon. A method in which a roll member is immersed, a solution in which a powder of a conductive substance is dissolved is infiltrated into the roll member, and then dried is used. Further, the hardness of the roller portion 502 is set in a range of 0.45 mm to 2.00 mm at a linear pressure of 3 g / cm and a compression amount of 0.45 mm to 2.00 mm. Thus, the roller portion 502 of the transfer roller 50
The hardness is a linear pressure of 3 g / cm and the compression amount is 0.45 mm ~
The reason for using a relatively soft material such as a foamed body such as urethane foam or silicone foam of 2.00 mm is as follows. That is, according to a test by the present inventors, when the roller portion of the transfer roller is made of a relatively hard material such as hard rubber, the pressure at the transfer point is high, and there is no problem with ordinary transfer paper. O
It has been found that when toner does not easily adhere to the film, such as a film for HP), a so-called hollow phenomenon that the center of the line remains on the image carrier side easily occurs. Then, the present inventors tested various transfer rollers produced by urethane foam. The volume electric resistance of the roller portion of the transfer roller was 10 ⁵ Ωcm, and the volume electric resistance of the transfer belt was 10 ¹¹ Ω.
cm, and the applied voltage of the transfer roller was 2.5 kV. As a result of the test, when the hardness of the roller portion is 3 g / cm in linear pressure and the compression amount is harder than 0.45 mm, a so-called hollow phenomenon occurs at the time of transfer to a film for an overhead projector (OHP), and When it was lowered, the so-called hollow phenomenon did not occur. However, when the compression amount exceeds 2.00 mm at a linear pressure of 3 g / cm and the hardness of the roller portion decreases,
It was found that the predetermined frictional force could not be obtained, and that the rotation with the transfer belt became difficult, and that the surface of the roller portion was damaged by the shearing force generated between the transfer belt and the roller portion. Accordingly, it was found that the hardness of the roller portion of the transfer roller is preferably in the range of 0.0.45 mm to 2.00 mm at a linear pressure of 3 g / cm and the amount of compression. Rotary shaft 5 constituting transfer roller 50
01 are rotatably supported by bearings 54 mounted on the support plate 36 (35). Bearing 54
The stopper 36 is positioned at a position facing the cylindrical stopper 361 (351) from the inner surface of the support plate 36 (35).
1 (351) side.
Therefore, it is difficult for toner powder and dust to enter the bearing 54 from the inside of the support plate 36 (35). In addition, a predetermined voltage is applied to the rotation shaft 501 of the transfer roller 50 by the voltage application unit 200 shown in FIG.

The tension roller 51 is disposed between the driven roller 49 and the transfer roller 50.
The rotary shaft 511 is formed of a columnar material made of an aluminum alloy, and both ends of the rotary shaft 511 are reduced in diameter.
11 is rotatably supported by a bearing 55 mounted on the support plate 36 (35).

The ground roller 52 is disposed between the transfer roller 50 and the drive roller 43, is formed of a columnar material made of an aluminum alloy, and has a reduced diameter rotating shaft 521 at both ends. The rotation shaft 521 is rotatably supported by a bearing 56 mounted on the support plate 36 (35). The earth roller 52 is
It is grounded by appropriate grounding means. The positional relationship between the ground roller 52, the tension roller 51, and the transfer roller 50 is configured as follows. That is,
The upper end of the outer peripheral surface of the transfer roller 50 is
The tension roller 51 is disposed below the straight line connecting the upper end of the tension roller 51 and the upper end of the tension roller 51 in the figure. Therefore, when a transfer belt 57 described later is stretched over each roller, the transfer roller 50 is separated from the transfer belt 57 (see FIG. 6).

The driving roller 43, the driven roller 49, the transfer roller 50, and the tension roller 51 mounted on the support plates 39 and 40 and the support plates 35 and 36 as described above.
And an endless transfer belt 57
Is wrapped around. The transfer belt 57 is formed of a semiconductive material such as polychloroprene.
The volume electric resistance value is set to 10 ⁹ to 10 ¹² Ωcm. When the transfer belt 57 is mounted on each of the rollers, the support plates 39 and 40 are connected to the support frame 31.
Of the support plates 39 and 40 and the end walls 33 and 34 of the support frame 31 are released by loosening the screws 42 fixed to the end walls 33 and 34 of the support frame 31. Rotate. Thus, the support plate 3
The transfer belt 57 can be easily fitted on each of the above rollers by rotating 9 and 40 around the pin 41 as a fulcrum. Next, by rotating the support plates 39 and 40 to the original position with the pin 41 as a fulcrum and tightening the screw 42, the transfer belt 57 can be attached with a predetermined tension. The width dimension of the transfer belt 57 is
The distance between the supporting plates 35 and 39 and the supporting plates 36 and 40 is larger than that of the supporting plates 35 and 39.
And 39 and the center of the support plates 36 and 40. Therefore, the toner powder adhered to the transfer belt 57 is transferred to the support plates 35 and 39 and the support plates 36 and 40 and the transfer belt 5.
7 hardly penetrates into the space formed by this.
In order to prevent the transfer belt 57 from meandering when the transfer belt 57 is operated, meandering prevention members 58, 58 are attached to the upper surfaces of the support plates 39, 40.

Next, a unit housing 60 for accommodating and supporting the belt unit 30 will be described with reference to FIG. The unit housing 60 in the illustrated embodiment includes a front side wall 63 and a rear side wall 64 as shown in FIG.
And a bottom wall 65, a left side wall 66, and a right side wall 67, which are open at the top and are integrally formed of synthetic resin. At the upper part of the front side wall 63 and the rear side wall 64 on the left side wall 66 side in FIG. 10, the mounting parts 391 and 401 provided on the support plates 39 and 40 for supporting the drive roller 43 of the belt unit 30 are rotated. Circular support holes 631 and 641 are formed so as to support as possible. The circular support holes 631 and 641 correspond to the diameters of the mounting portions 391 and 401, and are open at the top, respectively, and the opening widths thereof are parallel to two parallel surfaces 392, 392 formed on the mounting portions 391 and 401. 402, 402 correspond to the two plane widths. Accordingly, two parallel surfaces 392, 392 and 402, 40 of the mounting portions 391 and 401 are provided.
2 is inserted into the circular support holes 631 and 641 from above corresponding to the open portions of the circular support holes 631 and 641, and the belt unit 30 is turned by approximately 90 ° with the mounting portions 391 and 401 as fulcrums. The belt unit 30 can be mounted on the unit housing 60. The right side wall 6 of the front side wall 63 and the rear side wall 64
The end on the side of the belt unit 30 is formed so as to protrude forward and rearward.
Notch 632 to allow movement of 51 and 361
And 642 are each formed. A mounting portion 634 projecting below the bottom wall 65 is provided at a protruding portion of the front side wall 63 where the cutout portion 632 is formed. The mounting portion 634 has an elliptical shape as shown in FIG. And a hole 636 for inserting an oval mounting bolt. Further, a portion of the front wall 63 slightly leftward from the center in FIG. 5 is formed so as to protrude downward.
The protrusion has an engagement hole 633 at a position corresponding to a slide rail described later. The bottom wall 65 is provided with a slide rail 654 that protrudes downward at a position corresponding to the engagement hole 633 formed in the front side wall 63 and extends from the front end to the rear end. This sliding rail 65
4 are guides 655, 656 projecting downward on both sides.
And a sliding surface 65 formed between the guides 655 and 656.
The sliding surface 657 is formed at substantially the same position as the upper end of the engagement hole 633 formed in the front side wall 63. The bottom wall 65 has an opening 651 at the center and openings 652 and 653 at the front and rear ends on the right side wall 67 side. These openings 651, 652
The functions 653 and 653 will be described later.

The left side wall 66 of the unit housing 60
On the side, as shown in FIG. 6, a waste toner container 68 is formed in the front-rear direction along the left side wall 66. A toner conveying member 69 is provided below the waste toner container 68. The toner conveying member 69 includes a rotating shaft 691 and a spiral blade 692 mounted on the rotating shaft 691.
In the toner conveying member 69, one end of a rotating shaft 691 is rotatably supported by the front side wall 63, and the other end is opened to the waste toner accommodating portion 69 and provided to protrude rearward from the rear side wall 64. The spiral blade 6
A part of 92 is rotatably supported (see FIG. 10). A driven gear 70 is mounted on one end of the rotating shaft 691. The driven gear 70 is rotatably supported by a shaft 713 on the front wall 63 as shown in FIG.
One small gear 711 is engaged. The intermediate gear 7
1 is provided with a large gear 712 integrally with the small gear 711, and the large gear 712 is connected to the rotating shaft 43 of the drive roller 43.
The gear 45 is configured to mesh with the gear 45 mounted thereon. The other end of the rotating shaft 691 protrudes from the tip of the guide cylinder 693, and a closure board 694 having an outer diameter substantially equal to the outer diameter of the guide cylinder 693 is attached to the tip. The closing cylinder 72 is fitted into the guide cylinder 693 as shown in FIG. The closing cylinder 72 has an engagement groove 721 formed in the axial direction from the inner end thereof.
By engaging the projection 21 with the projection 695 provided on the guide cylinder 693, the cylinder 21 can move in the axial direction but its rotation is restricted. The closing cylinder 72 has a flange 7 at its inner end.
22 and the flange 722 and the rear side wall 64.
And is pressed backward by a coil spring 723 disposed between them.

The unit housing 60 is provided with cleaning means 73 for cleaning the transfer belt 57 of the belt unit 30 along the waste toner container 68. The cleaning means 73 in the illustrated embodiment includes a common holder 74, a cleaning blade 75, and a paper dust removing member 76. The common holder 74 is formed of a channel-shaped member having a length substantially equal to the width of the transfer belt 57,
1 and a support portion 742. A mounting member 77 is fixed to the center of the support portion 742 of the holder 74. The mounting member 77 is provided with a hole 771 having a circular cross-section having a part penetrating in the longitudinal direction at the base thereof and having an opening 772 at a part thereof, and an actuated lever 773 is integrally formed at the center of the mounting member 77. Is formed. This mounting member 77
A support shaft 78 (see FIG. 6) for rotatably supporting the unit housing 60 is provided on the bottom wall 65 of the unit housing 60. The support shaft 78 is integrally formed with support walls 79, 79 erected from the bottom wall 65.
And two parallel surfaces corresponding to the opening width of the opening 772 are formed on the outer periphery. In order to attach the mounting member 77 to the support shaft 78, the opening 772 is fitted to the support shaft 78 from above with the opening 772 corresponding to two parallel surfaces formed in the support shaft 78, and the mounting member 77 is attached. About 9
By turning by 0 °, the operated lever 773 is positioned so as to protrude from the opening 651 formed in the bottom wall 65 as shown in FIGS. The cleaning blade 75 is formed of urethane rubber or the like and has a length substantially the same as the width of the transfer belt 57,
The holder 74 is fixed to the mounting portion 741 with an adhesive or the like. At the time of transfer, the edge of the cleaning blade 75 is pressed against the transfer belt 57 (see FIG. 20) to scrape off the toner adhering to the transfer belt 57. The paper dust removing member 76 is made of a foam material such as a sponge, has a length substantially the same as the width of the transfer belt 57 similarly to the cleaning blade 75, and has an adhesive or the like attached to the mounting portion 741 of the holder 74. Has been fixed by. The paper dust removing member 76 is disposed downstream of the cleaning blade 75 in the operation direction of the transfer belt 57, and is formed to be thicker than the thickness of the cleaning blade 75. The portion is configured to be in contact with the transfer belt 57. The paper dust removing member 76 removes paper dust adhering to the transfer belt 57 that is difficult to remove by the cleaning blade 75, and removes toner remaining at the contact position when the cleaning blade 75 is separated from the transfer belt 57. It has the function of smoothing out. At the upper end of the left side wall 66 of the unit housing 60, a seal plate 80 that covers above the waste toner container 68 is mounted. This seal plate 80
Extends from the front wall 63 to the rear wall 64,
A sealing material 81 such as pile wool, sponge, felt or the like is attached to the surface facing the transfer belt 57 and the portion facing the cleaning blade 75.
Then, as shown in FIG. 6, the edge portion of the cleaning blade 75 is configured to be in contact with the sealing material 81 at the time of non-transfer. Therefore, toner, paper dust, and the like adhering to the edge of the cleaning blade 75 can be removed each time non-transfer.

Next, the transfer belt unit 29 constructed as described above is connected to the lower housing 2 of the clamshell type.
A slider mechanism for mounting the slider 5 will be described with reference to FIGS. The lower housing 25 includes a front plate 85, a rear plate 86 disposed at a distance from the front plate 85, and a substrate 90 disposed between the front plate 85 and the rear plate 86. As shown in FIG. 12, the detachable member 4 of the transfer belt unit 29 is attached to the front side plate 85.
6, a circular support hole 851 formed to open upward and corresponding to the fitting portion 464, a rectangular cutout 852 corresponding to the mounting portion 634 formed in the front wall 63 of the unit housing 60, and a description will be given later. A hole 853 that engages with the locking portion of the slider is provided. As shown in FIG. 13, the rear plate 86 is provided with a hole 861 corresponding to the fitting portion 472 of the position regulating member 47 in the transfer belt unit 29 and a hole 862 for allowing the closing cylinder 72 to be inserted. I have.

On the substrate 90 of the lower housing 25, a slider 87 extending between the front plate 85 and the rear plate 86 is provided. The slider 87 is made of a steel material having a channel cross section, and has a width equal to the width of the sliding surface 6 formed between the guides 655 and 656 of the sliding rail 654.
57 is formed in a size corresponding to the width of the upper plate 8.
The upper surface of 71 is a mounting surface 871a for mounting the sliding surface 657 of the sliding rail 654. Slider 8
7, first elongated holes 873, 873 and second elongated holes 874, 874 extending in the front-rear direction at the rear ends (upper side in FIG. 11, right side in FIGS. 15 to 18), respectively. Is provided. The first elongated holes 873, 873 provided on the rear end side are formed in a straight line parallel to the mounting surface 871a. The first slots 873, 87
Second long holes 874, 874 provided on the front end side than
Is a first parallel portion 874a parallel to the mounting surface 871a.
An inclined portion 874b inclined upward from the front end of the first parallel portion 874a; and a second parallel portion 87 parallel to the mounting surface 871a from the upper end of the inclined portion 874b toward the front end.
4c. Both side plates 872, 872
At the rear end, stoppers 875 and 875 projecting above the placement surface 871a are provided, respectively. The front ends of both side plates 872, 872 are fitted into holes 853 (see FIGS. 12 and 15) formed in the front side plate 85,
Locking recess 87 for holding slider 87 in an inclined state
A locking portion 876 provided with 6a is provided. The front end of the upper plate 871 has an engaging portion 87 that engages with an engaging hole 633 formed in the front side wall 63 of the unit housing 60.
7 are provided. The engaging portion 877 and the front side wall 6
The engaging holes 633 formed in the third member 3 constitute engaging means for engaging with each other. The slider 87 thus configured is
First long holes 87 formed in both side plates 872, 872
The first support pin 88 is inserted through the third and third holes 873, and the second support pin 89 is inserted through the second long holes 874 and 874. The first support pin 88 and the second support pin 8
9 are respectively supported by support brackets 901, 901 and 902, 902 formed by cutting and raising a part of the substrate 90. Both side plates 87 of the slider 87
2, 872, the first elongated holes 873, 873 and the second elongated holes 874, 874 and the support bracket 901,
A first support pin 88 and a second support pin 89 respectively supported by 901 and 902, 902
Is configured to be movable in the front-rear direction and to be swingable in the vertical direction with the rear end as a fulcrum. A tension coil spring 92 is stretched between the second support pin 89 and a locking portion 878 provided on the upper plate 871 of the slider 87 at a rear end side of the second support pin 89, The slider 87 is constantly urged to move to the front end side by the tension of the tension coil spring 92. Therefore, the slider 87 has its front end in contact with the front side plate 85 in the assembled state (see FIG. 11). At this time, the first support pins 88 are attached to both side plates 8 of the slider 87.
The second support pin 89 is located at a substantially intermediate portion between the first elongated holes 873 and 873 provided in the second elongated holes 874 and 873 and the inclined portion 874b and the second parallel portion 87 of the second elongated holes 874 and 874.
4c and the connection portion. From this state, when the front end of the slider 87 is lifted upward,
The slider 87 rotates about the first support pin 88 while rotating the second elongated hole 8 through which the second support pin 89 is inserted.
74, 874 to move to the front end side,
6 reaches a hole 853 formed in the front side plate 85, FIG.
As shown in FIG. 5, the locking portion 876 fits into the hole 853,
The lower edge of the lock 53 and the locking concave portion 876 a of the locking portion 876 are engaged with each other, and the slider 87 is held in an inclined state in which the front end is positioned above the upper end of the front side plate 85. At this time, the rear ends of the first long holes 873, 873 are located on the first support pins 88, and the rear ends of the first parallel portions 874a of the second long holes 874, 874 are the second support pins 874, 874. Positioned on pin 89.

The slider mechanism for mounting the transfer belt unit 29 on the lower housing 25 of the clamshell type is constructed as described above. Hereinafter, the procedure for mounting the transfer belt unit 29 will be described. First, the front end of the slider 87 is lifted upward, and the locking concave portion 876a of the locking portion 876 is engaged with the lower edge of the hole 853 formed in the front side plate 85 and held in an inclined state as shown in FIG. I do. In this state, the slide surface 657 of the slide rail 654 formed on the unit housing 60 of the transfer belt unit 29 is placed on the placement surface 871a of the slider 87, and the transfer belt unit 29 is placed on the placement surface of the slider 87. When the slider is moved along the position 871a and reaches the position shown in FIG. 16, the rear end of the slide rail 654 contacts the stoppers 875 and 875 provided at the rear end of the slider 87. On the other hand, the engaging hole 633 formed in the front side wall 63 of the unit housing 60 engages with the engaging portion 877 provided on the slider 87, and the transfer belt unit 29 and the slider 87 are integrated. At this time, the driven gear 48 attached to the drive roller 43 of the transfer belt unit 29 is inserted into the hole 86 formed in the rear plate 86.
1 and the guide portion 471 of the position regulating member 47 is in contact with the upper edge of the hole 861. Further, the closing cylinder 7 fitted to the guide cylinder 693 of the toner conveying member 69
2 is inserted into a hole 862 formed in the rear side plate 86. When the transfer belt unit 29 and the slider 87 are pushed backward from the state shown in FIG.
Is disengaged from the hole 853, the transfer belt unit 29 and the slider 87 pivot downward about the first support pin 88 while the second support pin 89 is inserted through the second support pin 89. Guided by the long holes 874, 874, FIG.
As shown in FIG. 6, when the horizontal state is reached, the mounting portion 6 of the front side wall 63 is formed.
The bottom wall 65 corresponding to the position 34 contacts the bottom edge 854 of the notch 852 formed in the front side plate 85. At this time, the position regulating member 47 is guided by the guide portion 471 having a conical surface into the hole 861 formed in the rear side plate 86, the fitting portion 472 is fitted and positioned, and the flange portion 473 is fixed to the rear side plate 86. Abut. The closing cylinder 72 fitted to the guide cylinder 693 of the toner conveying member 69 is provided with a hole 9 provided in a waste toner box 95 provided behind the rear side plate 86.
51, and the flange 722 contacts the rear side plate 86. A small-diameter portion between the detachable member 46 mounted on the front end of the drive roller 43 and the gear 45 is fitted into a circular support hole 851 formed in the front side plate 85 from its upper opening.
When the transfer belt unit 29 and the slider 87 are further pushed backward from the state shown in FIG. 17, the mounting portion 634 comes into contact with the front side plate 85 as shown in FIG. At this time, FIG.
2, the positioning pins 9 provided on the front side plate 85
6 is fitted with a positioning hole 635 formed in the mounting portion 634. The attachment / detachment member 46 is guided by the conical surface of the guide portion 463 constituting the position regulating means 465 and moves in the circular support hole 851.
The position is regulated by fitting with 1. In this state, as shown in FIG. 12, the mounting bolt 971 is inserted into the mounting bolt insertion hole 636 formed in the mounting portion 634 and screwed into the screw hole formed in the front side plate 85. By inserting the mounting bolts 972 and 973 into the mounting bolt insertion holes 461 and 462 formed in the above and screwing into the screw holes formed in the front side plate 85, the transfer belt unit 29 is a clamshell type lower housing. 25. On the other hand, on the rear end side of the transfer belt unit 29, a driven gear 48 mounted on the driving roller 43 is rotatably mounted on a short shaft 98 mounted on the rear plate 86 as shown in FIG. It meshes with a transmission gear 99 that is operatively connected to the device. Further, the closing cylinder 72 fitted to the guide cylinder 693 of the toner conveying member 69 does not move because the flange 722 abuts on the rear side plate 86, but since the guide cylinder 693 moves, the distal end thereof moves from the closing cylinder 72. The waste toner that projects into the waste toner box 95 and is transported by the toner transport member 69 can be discharged. When the transfer belt unit 29 mounted on the lower housing 25 as described above is removed for component replacement or the like, the transfer belt unit 29 can be easily removed by performing the reverse operation of the above mounting procedure.

FIG. 19 shows the positional relationship between the transfer belt unit 29 and the image carrier 3 in a state where the transfer belt unit 29 is mounted on the lower housing 25 constituting the clamshell type body housing as described above. That is, the transfer roller 50 of the transfer belt unit 29 is positioned substantially directly below the image carrier 3 so as to face each other, and a gap is provided between the transfer belt 57 and the image carrier 3. Also, a gap of about 1.00 mm to 2.00 mm is provided between the transfer belt 57 and the transfer roller 50. As described above, during transfer, the belt unit 30 of the transfer belt unit 29 mounted on the lower housing 25 constituting the body housing is rotated upward about the drive roller 43 by contact / separation means described later. At the transfer position, the transfer belt 57 contacts the outer peripheral surface of the image carrier 3 and is pressed by the transfer roller 50 as shown in FIG. Hereinafter, the contact / separation means will be described mainly with reference to FIGS. 11, 19, and 20.

The contacting / separating means has an operating shaft 100 which is disposed above and below a substrate 87 constituting the lower housing 25 and is rotatably supported by a front plate 85 and a rear plate 86. At the rear end of the operation shaft 100, a lever 101 that is operated by a cam described later is attached. A cam 102 for operating the lever 101 is mounted on a rotating shaft 103 rotatably supported on the front side plate 85. A tension coil spring 105 is mounted between the lever 101 and the front side plate 85, so that the lever 101 is always in contact with the outer peripheral surface of the cam 102. A driven gear 104 is mounted on the rotating shaft 103, and the driven gear 104 is operatively connected to a driving device (not shown). Therefore, when the driven gear 104 is driven to rotate, the cam 10
The lever 101 that is in contact with the outer peripheral surface of the lever 2 rotates in a predetermined angle range, and reciprocates the operating shaft 100 in a predetermined angle range. The operating shaft 100 includes a front plate 85 and a rear plate 86.
The operation levers 106 and 107 made of spring steel are attached at positions slightly closer to the center of each. The operation levers 106 and 107 for contact and separation are formed in an opening 652 formed in the bottom wall 65 of the unit housing 60 of the transfer belt unit 29 mounted on the lower housing 25.
And 653. An actuated lever 77 formed on an attachment member 77 for attaching a holder 74 on which the cleaning blade 75 and the paper dust removing member 76 are attached is provided at a central portion of the operation shaft 100.
A cleaning operation lever 108 made of spring steel and in contact with the upper surface of the cleaning lever 3 is mounted. The operated lever 773, the cleaning operation lever 108, the operation shaft 100, the lever 101, the cam 102, and the like include a cleaning blade 75 and a paper dust removing member 76.
Is configured to actuate the holder 74 on which is mounted in accordance with the operation direction of the belt unit 60 by the contact / separation means, and is operated by a common drive source with the contact / separation means.

The transfer device of the image forming machine according to the illustrated embodiment is configured as described above, and its operation will be described below. Transfer belt unit 29 to lower housing 2
When the image forming apparatus is operated from the state (FIG. 19) mounted on the drive gear 5 as described above, the driven gear 104 is rotationally driven by a driving device (not shown). When the driven gear 104 is rotationally driven, the cam 102 is also rotated and stopped when it reaches the transfer position shown in FIG. Cam 1
As 02 rotates to the transfer position shown in FIG. 20, the lever 101 which is in contact with the outer peripheral surface of the cam 102 swings upward, causing the operating shaft 100 to rotate counterclockwise in FIG. Accordingly, the operation levers 106 and 107 for attachment and detachment mounted on the operation shaft 100 are swung upward, and abut against the lower surfaces of the support plates 35 and 36 constituting the belt unit 30 so that the belt unit 30 is rotated about the driving roller. Rotate upward and push up. As a result, the transfer belt 57 is pressed against the image carrier 3, and
0 is pressed against the transfer belt 57. The roller portion of the transfer roller 50 is compressed by about 0.5 mm to 1.0 mm by this pressure contact, so that the transfer belt 57 can uniformly contact the image carrier 3 with a predetermined pressure contact force. on the other hand,
The cleaning operation lever 108 mounted on the operation shaft 100 is swung downward. Therefore, the mounting member 77 having the operated lever 773 in contact with the operation lever 108 is illustrated around the support shaft 78. At 20 it is turned clockwise. Thereby, the mounting member 77
The holder 74 on which the cleaning blade 7 is mounted moves to the position shown in FIG.
5 is pressed against the transfer belt 57. In this state, the edge of the paper dust removing member 76 attached to the holder 74 on the cleaning blade 75 side is brought into contact with the transfer belt 57.

Next, when the driven gear 48 is driven to rotate via a transmission gear 99 which is operatively connected to the above-mentioned driving device, the driving roller 43 on which the driven gear 48 is mounted is driven.
Is rotated. When the drive roller 43 rotates, the transfer belt 57 is operated in the direction of arrow B. Also,
When the driving roller 43 rotates, the driven gear 70 is rotated via the gear 45 and the intermediate gear 71 mounted on the driving roller 43. When the driven gear 70 rotates, the toner conveying member 69 to which the driven gear 70 is attached rotates. On the other hand, the transfer roller 50 is
(See FIG. 1), a predetermined voltage is applied. The transfer belt 57 is charged with electric charge of a predetermined polarity via the transfer roller 50. Therefore, when the transfer paper is supplied between the image carrier 3 and the transfer belt 57, the charge of the transfer belt 57 in the transfer portion where the image carrier 3 and the transfer belt 57 face each other causes the image carrier to be charged. The toner images formed on the surface of No. 3 are sequentially sucked and transferred to a transfer sheet. The transfer paper on which the toner image has been transferred is transferred to a transfer belt 57.
And is fixed by the fixing roller pair 23 and discharged from the discharge roller pair 24. Note that the toner adhered to the surface of the transfer belt 57 is scraped off by the cleaning blade 75 while moving in the direction of arrow B, and falls into the waste toner container 68. The toner that has fallen into the waste toner storage section 68 is transported rearward by the toner transport member 69, and is discharged into the waste toner box 95 from the tip of the guide cylinder 693.

Next, at the time of non-transfer, the driving roller 43 is stopped, and the voltage application to the transfer roller 50 is cut off. Then, the driven gear 104 is rotationally driven by a driving device (not shown), and the cam 102 is positioned at the position shown in FIG. As the cam 102 rotates to the position shown in FIG. 19, the lever 101 that is in contact with the outer peripheral surface of the cam 102 swings downward, causing the operating shaft 100 to rotate clockwise in FIG. Therefore, the operation levers 106 and 107 for attachment and detachment mounted on the operation shaft 100 are pivoted downward, so that the belt unit 30 pivots downward around the drive roller and the support plates 35 and 36 FIG. 19
The state of the non-transfer position shown in FIG. That is, the image carrier 3 and the transfer belt 57 are separated from each other, and the transfer belt 57 and the transfer roller 50 are separated from each other. Therefore, the deformation of the transfer roller 50 caused by the transfer roller 50 constantly contacting the transfer belt 57 can be prevented.
On the other hand, the cleaning operation lever 108 mounted on the operation shaft 100 is swung upward, so that the mounting member 77 having the operated lever 773 in contact with the operation lever 108 is centered on the support shaft 78. 19, it is rotated clockwise in FIG. As a result, the holder 74 to which the attachment member 77 is attached is operated to the position shown in FIG. 19, and the cleaning blade 75 attached to the holder 74 is separated from the transfer belt 57. Therefore, the deformation of the transfer belt 57 caused by the cleaning blade 75 being constantly pressed against the transfer belt 57 can be prevented. Also in this state, the edge of the paper dust removing member 76 mounted on the blade holder 74 on the side opposite to the cleaning blade 75 side is brought into contact with the transfer belt 57. As described above, since the paper dust removing member 76 is always in contact with the transfer belt 57, the toner that has accumulated and adhered to the position where the cleaning blade 75 of the transfer belt 57 was in contact with the belt unit 30 when separated is separated. Even if the transfer belt is moved by the inertia of the transfer belt until it stops, the transfer belt is leveled by the paper dust removing member 76. Can be prevented beforehand.

[0031]

The transfer device of the image forming apparatus according to the present invention is constructed as described above, and the transfer roller is disposed separately from the transfer belt. When the belt unit is positioned at the transfer position by the contact / separation means. Since the transfer roller is configured to press the transfer belt against the image carrier, the transfer roller presses the transfer belt against the image carrier when the belt unit is positioned at the transfer position by the contact / separation means during transfer, and contacts and separates during non-transfer. When the belt unit is positioned at the non-transfer position by means, the transfer belt is separated from the image carrier and the transfer roller is separated from the transfer belt. Therefore, at the time of non-transfer, the transfer roller can be separated from the transfer belt while the transfer belt is separated from the image carrier, so that even if the transfer roller is made of a soft material such as sponge rubber or urethane foam, the transfer roller can be separated. Can be prevented from being deformed due to being constantly pressed against the transfer belt, and transfer failure due to the deformation of the transfer roller can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus equipped with a transfer device configured according to the present invention.

FIG. 2 is a front view of a clamshell type image forming machine equipped with a transfer device configured according to the present invention.

FIG. 3 is a perspective view of a transfer belt unit included in a transfer device configured according to the present invention.

FIG. 4 is a plan view of the transfer belt unit shown in FIG. 3;

FIG. 5 is a front view showing a part of the transfer belt unit shown in FIG. 3 cut away;

FIG. 6 is a sectional view of the transfer belt unit shown in FIG. 3;

FIG. 7 is a perspective view of a belt unit constituting the transfer belt unit shown in FIG.

FIG. 8 is a sectional view of a driving roller constituting the belt unit shown in FIG. 7;

FIG. 9 is a sectional view showing a support structure of each roller constituting the belt unit shown in FIG. 7;

FIG. 10 is a perspective view of a unit housing constituting the transfer belt unit shown in FIG. 3;

FIG. 11 is a plan view showing a mounting portion of a body housing on which the transfer belt unit shown in FIG. 3 is mounted.

FIG. 12 is a front view showing a state in which the transfer belt unit shown in FIG. 3 is mounted on the body housing.

FIG. 13 is a rear view showing a state in which the transfer belt unit shown in FIG. 3 is mounted on the body housing.

FIG. 14 is a perspective view of a slider for attaching the transfer belt unit shown in FIG. 3 to a body housing.

FIG. 15 is a side view showing a state where the slider shown in FIG. 14 is pulled out;

FIG. 16 is a side view showing a state where the transfer belt unit is mounted on the slider shown in FIG. 15;

17 is a side view showing a state in which the transfer belt unit is placed on the slider shown in FIG. 16 and the slider and the transfer belt unit are pushed into the body housing.

18 is a side view showing a state where the slider and the transfer belt unit have been moved to a predetermined mounting position of the machine housing from the state shown in FIG.

FIG. 19 is a cross-sectional view of the transfer device mounted on the machine housing.

FIG. 20 is a cross-sectional view of the transfer device mounted on the machine housing in a transfer state.

[Explanation of symbols]

 2: Image forming machine 3: Image carrier 4: Corona discharger for charging 5: Developing device 6: Transfer device 7: Cleaning unit 8: Static elimination lamp 9: Irradiation lamp 10: First mirror 11: Second mirror 12 : Third mirror 13: Lens 14: Fourth mirror 15: Transfer paper supply device 16: Transfer paper cassette 17: Transfer paper feed roller 18: Paper feed roller pair 19: Guide path 20: Transport roller pair 21: Guide path 22: registration roller pair 23: fixing roller pair 24: discharge roller pair 25: lower housing 26: upper housing 29: transfer belt unit 30: belt unit 31: support frame 35: support plate 36: support plate 39: support plate 40 : Support plate 43: drive roller 46: detachable member 47: position regulating member 48: driven gear 49: driven roller 50: transfer roller 51: Cushion roller 52: earth roller 57: transfer belt 58: meandering prevention member 60: unit housing 63: front wall 64: rear wall 65: bottom wall 66: left wall 67: right wall 68: waste toner container 74: holder 75: Cleaning blade 76: Paper dust removing member 80: Seal plate 81: Seal material 85: Front plate 86: Rear plate 87: Slider 90: Substrate 88: First support pin 89: Second support pin 92: Tension coil spring 100 : Working shaft 102: Cam 104: Driven gear 105: Tension coil spring 106: Working lever for contact / separation 107: Working lever for contact / separation 108: Cleaning blade operating lever 654: Sliding rail 873: First slot 874: Second long hole 876: locking portion 877: engaging portion

Continuation of the front page (72) Inventor Keio Fujita 1-2-2, Tamazo, Chuo-ku, Osaka City Inside Mita Kogyo Co., Ltd. (56) References JP-A-5-107952 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/16

Claims (3)

(57) [Claims] A driving roller; a driven roller disposed at a distance from the driving roller; a transfer belt stretched between the driving roller and the driven roller; A belt unit having a transfer roller disposed opposite to the image carrier, contacting / separating means for operating the belt unit to a transfer position and a non-transfer position, and applying a predetermined voltage to the transfer roller. Voltage applying means,
In a transfer device of an image forming machine that transfers a toner image formed on an image carrier to copy paper supplied between the transfer belt and the image carrier, and conveys the transfer paper on which the toner image is transferred, The transfer roller is disposed separately from the transfer belt. When the belt unit is positioned at a transfer position by the contact / separation means, the transfer roller presses the transfer belt against the image carrier. A transfer device for an image forming machine, comprising: 2. The belt unit comprises: a tension roller disposed upstream of the transfer roller in the transfer belt movement direction; and an earth roller disposed downstream of the transfer roller in the transfer belt movement direction. The transfer roller is provided between the tension roller and the ground roller, and is separated from the drive roller, the driven roller, and the transfer belt stretched over the tension roller and the ground roller. A transfer device for an image forming machine according to claim 1. 3. The transfer roller includes a rotating shaft and a roller mounted on the rotating shaft, and the hardness of the roller is a linear pressure of 3 g / cm and a compression amount of 0.45 mm to 2.00 mm. The transfer device for an image forming machine according to claim 1, wherein the transfer device is set in a range of: