Source: http://www.google.com/patents/US6619657?dq=5787449
Timestamp: 2017-11-18 07:42:03
Document Index: 791565574

Matched Legal Cases: ['art 2', 'art 2', 'art 3', 'art 26', 'art 3', 'art 3', 'art 14', 'art 2', 'art 102', 'art 103', 'art 104', 'art 105', 'art 106', 'art 107', 'art 104', 'art 105', 'art 106', 'art 106']

Patent US6619657 - Curl correction device, and image forming apparatus having the curl ... - Google Patents
A sheet conveying device includes an endless belt for conveying a sheet, at least two stretching shafts arranged to revolvably stretch the endless belt, a rotatable pressing roller arranged to push the stretched endless belt from outside, the sheet being arranged to be conveyed in a state of being pinched...http://www.google.com/patents/US6619657?utm_source=gb-gplus-sharePatent US6619657 - Curl correction device, and image forming apparatus having the curl correction device
Publication number US6619657 B2
Application number US 09/805,175
Also published as US20010024013
Publication number 09805175, 805175, US 6619657 B2, US 6619657B2, US-B2-6619657, US6619657 B2, US6619657B2
Inventors Jun Horikoshi, Kenji Suzuki
Patent Citations (27), Referenced by (33), Classifications (4), Legal Events (4)
Curl correction device, and image forming apparatus having the curl correction device
US 6619657 B2
an endless belt for conveying a sheet;
at least two rollers arranged to support said endless belt;
a rotatable pressing roller arranged to push said endless belt from outside, the sheet being conveyed in a state of being pinched between said endless belt and said rotatable pressing roller; and
an elastic member for pressing said rotatable pressing roller in a direction to push said endless belt, wherein said rotatable pressing roller is movable in a direction to separate from said endless belt.
2. A sheet conveying device according to claim 1, wherein said elastic member presses a rotation shaft of said rotatable pressing roller.
2π/6(rad)≦α≦5π/6(rad).
5. A sheet conveying device according to claim 4, wherein said rotatable pressing roller is located adjacent to an intersection point at which an upstream-side conveying path and a downstream-side conveying path are connected to each other.
β=α±π/6.
a sheet conveying device comprising:
an elastic member for pressing said rotatable pressing roller in a direction to push said endless belt, wherein said rotatable pressing roller is movable in a direction to separate from said endless belt; and
image forming means for forming an image on a sheet conveyed by said sheet conveying device.
a sheet housing part arranged to allow sheets to be stacked therein;
a sheet conveying path formed from said sheet housing part up to said image forming means; and
a sheet resupply path arranged to supply to said image forming means again a sheet having an image formed thereon by said image forming means,
wherein said sheet conveying device is disposed on said sheet resupply path.
9. An image forming apparatus according to claim 8, wherein said sheet resupply path has one end on a downstream side thereof connected to said sheet conveying path.
an endless belt arrange to circulate in a state of being wrapped around a plurality of guide rollers;
at least one curl correction roller arrange to press said endless belt in such a direction as to warp said endless belt; and
pressing springs for urging said at least one curl correction roller in the direction of warping said endless belt,
wherein, from among said plurality of guide rollers, a driving guide roller to which a rotative driving force is imparted is formed to have a straight generatrix, and curl of a curled sheet is corrected while the curled sheet is conveyed jointly by said endless belt and said curl correction roller.
12. A curled-sheet correction device according to claim 11, wherein said curl correction roller is arranged to press a tension side of said endless belt.
a curled-sheet correction device comprising:
wherein, from among said plurality of guide rollers, a driving guide roller to which a rotative driving force is imparted is formed to have a straight generatrix, and curl of a curled sheet is corrected while the curled sheet is jointly conveyed by said endless belt and said at least one curl correction roller, said curled-sheet correction device being arranged to remove curl of the sheet having an image formed thereon by said image forming means.
two-sides inverting means for inverting two sides of the sheet having an image formed thereon by said image forming means and then discharging the sheet; and
wherein, from among said plurality of guide rollers, a driving guide roller to which a rotative driving force is imparted is formed to have a straight generatrix, and curl of a curled sheet is corrected while the curled sheet is jointly conveyed by said endless belt and said at least one curl correction roller, said curled-sheet correction device being disposed at said two-sides inverting means.
17. A sheet conveying device, comprising:
an endless belt arranged to convey a sheet;
at least two supporting rotary members arranged to support said endless belt;
a pinching rotary member arranged to pinch the sheet in conjunction with said endless belt; and
an elastic member for warping said endless belt along a circumferential surface of said pinching rotary member by urging said pinching rotary member,
wherein said pinching rotary member is supported in such a way as to be movable against an urging force of said elastic member by rigidity of the sheet pinched by said endless belt and said pinching rotary member.
18. A sheet conveying device according to claim 17, further comprising support means for movably supporting said rotary member urged by said elastic member.
Further, in the sheet conveying device, the pressing roller is located adjacent to an intersection point at which an upstream-side conveying path and a downstream-side conveying path are connected to each other.
Further, an image forming apparatus comprises the above-stated sheet conveying device, and image forming means for forming an image on a sheet conveyed by the sheet conveying device.
The image forming part 2 is provided with an electrophotographic photosensitive drum 2 a (hereinafter referred to simply as the photosensitive drum) which is arranged as an image bearing body to have an electrostatic latent image electrophotographically formed thereon, a laser scanner 2 b which is arranged to form a latent image on the photosensitive drum 2 a, a reflection mirror 2 c, a developer 2 d, a primary charger 2 e arranged to electrify the photosensitive drum 2 a, a transfer charger 2 f, etc. At the image forming part 2, the surface of the photosensitive drum is supplied with laser beams corresponding to image information obtained by the emitting and scanning action of the laser scanner 2 b. By this, a latent image is formed on the surface of the photosensitive drum 2 a, which is uniformly electrified and charged by the primary charger 2 e. Then, a toner image is formed with the latent image developed by the developer 2 d.
The toner image is transferred onto the first surface of the sheet P by the transfer charger 2 f, which is disposed below the photosensitive drum 2 a, when the sheet P is conveyed by the registration roller pair 24 in synchronism with the rotation of the photosensitive drum 2 a. The sheet P to which the toner image has been transferred is conveyed to the fixing part 3 by the belt conveying part 26 disposed in the middle part of the apparatus. With the sheet P thus conveyed to the fixing part 3, the toner image on the surface of the sheet P is fixed through a heating-and-pressing fixing process of the fixing part 3.
In conveying the sheet P, the curl correction means 10 operates as follows. When the sheet P is led to the two-sided-print conveying path 4 for two-sided printing, the sheet P is supplied to the curl correction means 10 by the conveying roller pairs 22 f, 22 g and 22 h.
At the curl correction means 10, the sheet P is moved in the direction of an arrow shown in each of FIGS. 2 and 3, and, then, the lower portion of the fore end of the sheet P rides onto the main surface part 14 a of each endless belt 14 on the driven belt shaft 11, which is revolving, so that the sheet P is conveyed by the endless belts 14. At this time, the sheet P is caused to move along the upper guide member 30 a, which is slanting downward. The fore end part of the sheet P is thus supplied to a nip part between the pressing roller 13 and the endless belt 14 to be conveyed further by the main surface (hereinafter referred to as the sheet conveying surface) of each endless belt 14. The sheet P thus passes through the curl correction means 10. By passing the V sectional shape part of the sheet conveying surface of each endless belt 14 formed across the pressing roller 13 between the upstream and downstream sides of the sheet conveying surface, a curled state of the sheet P is corrected according to the angle of the V sectional shape. After passing through the curl correction means 10, the sheet P is led to the sheet conveying path 21 to be supplied again to the image forming part 2 through the conveying roller pair 22 c and the registration roller pair 24.
Further, as shown in FIG. 8, an angle β which the pressing roller 13, the endless belt 14, the driving belt shaft 12 and the driven belt shaft 11 make with each other is an angle bending in the same direction as the angle β, and is arranged to be “β=α±π/6”, which is about the same as the angle α.
Further, in the case of the second embodiment, the curl correction means is set at “α=7π/12 rad (105°)” and “β=11π/18 rad (110°)”. However, the advantageous effect of the invention may be attainable by setting the curl correction means at a wider range, which is not less than “α=2π/6 (rad)” and not greater than “5π/60 (rad)”, and “β=α±π/6”.
Referring to FIG. 9, the body 100 of the printer 140 is divided into three parts, i.e., a first body 100 a, a second body 100 b and a third body 100 c. The body 100, however, may be formed in one body without dividing it. The essential parts of the printer 140 are disposed in the first body 100 a. The curled-sheet correction device 50 is disposed in the second body 100 b. A post-processing apparatus, such as a stapler, a puncher, or the like, which is not shown, is disposed in the third body 100 c.
The first body 100 a includes a reader part 102 arranged to read an original to be copied, a sheet supply part 103 arranged to supply sheets S, an image recording part 104 arranged to turn information on the original into a toner image by an electrophotographic process, a transfer part 105 arranged to transfer the toner image onto the sheet S supplied thereto, a fixing-and-delivery part 106 arranged to fix the toner image to the sheet S and to deliver the sheet S, and a part of an inverse conveying part 107 arranged to invert and convey the sheet S. Image forming means is formed jointly by the image recording part 104 and the transfer part 105.
At step S7, after timing adjustment to the image signal, the sheet S is fed to the transfer belt 116. The transfer belt 116 is caused to revolve by the driving roller 116 a at a speed a little slower than the speed of feeding by the registration roller pair 114. The sheet S is then attracted by the surface electric charge of the transfer belt 116 imparted by the charger 116 b.
At step S8, the sheet S attracted by the transfer belt 116 is conveyed in synchronism with the image signal on the photosensitive drums 5Y, 5M, 5C and 5Bk. The sheet S on the transfer belt 116 is brought into contact first with the photosensitive drum 5Y to transfer an yellow toner image on the photosensitive drum 5Y to the sheet S by means of the transfer charger 8Y. After that, the toner images of magenta, cyan and block colors are likewise transferred at the other photosensitive drums 5M, 5C and 5Bk one after another to form a full-color image on the sheet S. Then, the flow proceeds from the step S8 to step S9. At the step S9, the toner image on the sheet S is sent to the fixing-delivery part 106. At the part 106, the toner image is fixed through the nip part of the fixing-and-pressing roller pair 117 by heating and pressing.
The relation of the circumferential speed of the belt to a sheet conveying speed is next described with reference to FIG. 13. For the sake of simplification, the diameter φd of the driving roller 55 is assumed to be equal to that of the pressing roller 58. Referring to FIG. 13, with the driving roller 55 rotated to an angle α°, the inner circumferential progressing distance L of each of the endless belts 57 at the driving roller 55 can be expressed as follows: L=d·π·(α/360)
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U.S. Classification 271/188
Cooperative Classification B65H5/025
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HORIKOSHI, JUN;SUZUKI, KENJI;REEL/FRAME:011797/0162