CN101644905A - Sheet discharging device and image forming apparatus including the sheet discharging device - Google Patents
Sheet discharging device and image forming apparatus including the sheet discharging device Download PDFInfo
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- CN101644905A CN101644905A CN200910161910A CN200910161910A CN101644905A CN 101644905 A CN101644905 A CN 101644905A CN 200910161910 A CN200910161910 A CN 200910161910A CN 200910161910 A CN200910161910 A CN 200910161910A CN 101644905 A CN101644905 A CN 101644905A
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Abstract
The invention relates to a sheet discharging device and an image forming apparatus including the sheet discharging device. In a sheet discharging unit including a pair of sheet discharge rollers whichdischarges a sheet P, the outer diameter of a sheet discharge drive roller included in the pair of sheet discharge rollers is set so that the outer diameter of a straight portion which is a central portion in the width direction perpendicular to the discharging direction of the sheet P is larger than the outer diameters of both end portions in the width direction. Further, in the sheet discharging unit, the pair of sheet discharge rollers respectively include metal shafts extending in the width direction and elastic layers respectively wound around the metal shafts and continuously formed tobe longer in the width direction than the width of a sheet P with a passable maximum size. Further, at least one elastic layer of the pair of sheet discharge rollers is formed of a foamed material.
Description
Technical field
The present invention relates to adopt electrostatic recording system and electrophotographic recording system image forming apparatus sheet discharging apparatus and comprise the image forming apparatus of this sheet discharging apparatus.
Background technology
In recent years, image forming apparatus miniaturization and high performance, and developed intermediate transfer type full-colour image forming device with the disclosed structure of US6970665.Fig. 5 with reference to the application illustrates the disclosed invention of US6970665.
As shown in Figure 5, image forming apparatus 200 comprises a plurality of image forming parts 10.Image forming part 10 utilizes light, magnetic and electric charge to form sub-image on the photosensitive drums 11 as image bearing member, utilizes and makes this image development as developers such as toners, thereby obtain visual image.Image forming apparatus 200 also comprises secondary transfer roller 36 and is arranged on the intermediate transfer unit 30 of the top of image forming part 10.To be transferred to intermediate transfer unit 30 in turn from the visual image of image forming part 10, intermediate transfer unit 30 forms multicolor image.Secondary transfer roller 36 is transferred to the multicolor image on the intermediate transfer unit 30 on the sheet material P.Image forming apparatus 200 also comprises fixation unit 40 and sheet material discharge parts 250, this fixation unit 40 is used for and will be transferred to multicolor image photographic fixing on the sheet material P to sheet material P, and this sheet material is discharged parts 250 and is used for having the sheet material P of image to be discharged to the outside of image forming apparatus 200 photographic fixing.In addition, be used for that sheet material P is transported to the sheet material supply unit 20 of the Te of secondary transfer printing portion and be used for sheet material P is supplied to the manual feed trays 71 and the sheet material box 21 of sheet material supply unit 20 in the arranged beneath of the secondary transfer roller 36 of image forming apparatus 200.
When the visual image on the middle transfer printing unit 30 arrives the position of the secondary transfer printing Te of portion, by secondary transfer roller 36 with this visual image secondary transfer printing to the sheet material P that chooses from manual feed trays 71 or sheet material box 21 and carry, and carry out further photographic fixing by 40 pairs of these visual images of fixation unit.Discharging parts 250 by sheet material has the sheet material P of image to be discharged to the outside of image forming apparatus 200 photographic fixing, can obtain full-colour image thus.Sheet material is discharged pallet 60 and is disposed in the downstream that sheet material is discharged the sheet material throughput direction of parts 250.Sheet material is discharged pallet 60 can accommodate the sheet material P that is discharged parts 250 discharges by sheet material.
As shown in Figure 6, sheet material discharge parts 250 comprise a plurality of concavo-convex rollers 501.Discharge parts 250 according to this sheet material, make sheet material P strengthen (stiffen), thus, removing under the state that curls of sheet material P, can discharge sheet material P by the state of the posture all-the-time stable of sheet material P when discharging.The front end of the sheet material P that discharges can not released the sheet material P that before has been stacked in the sheet material discharge pallet 60, but discharges sheet material P with the state that sheet material P fitly is configured in the sheet material discharge pallet 60.
In addition, discharge parts 250 for sheet material, replace the concavo-convex roller 501 of TOHKEMY 2006-117365 communique and Fig. 6, US communique 2007/0201892 proposes to use the sheet material distributing roller right, this sheet material distributing roller centering, be wrapped in the width of the length of the rubber layer on the roll shaft greater than sheet material P.With reference to Fig. 7 the 2007/0201892 disclosed invention of US communique is described.
As shown in Figure 7, discharge parts 350 according to this sheet material, the elastic layer that sheet material is discharged driven roller 503 contacts with sheet material P equably with the whole width that sheet material is discharged the elastic layer of driven voller 504, therefore, the heat of sheet material P is led away equably, can prevent the brightness disproportionation of image thus.In addition, because the edge part of roller does not contact with sheet material P, therefore, can prevent from sheet material P, to stay the vestige of roller.
Yet, when using shown in Figure 6 concavo-convex roller 501, contact to the surface of roller and sheet material P heterogeneity.In this case, for the sheet material P that passes through fixation unit 40, because sheet material P's is being different with roller surface contact portion and noncontact part aspect the heat of the sheet material P that is derived by the roller surface, therefore, cause by the cooling condition difference of the toner image of photographic fixing to the sheet material P.Therefore, partly cause the brightness disproportionation of the image on the sheet material P with roller surface contact portion and noncontact.Especially, when using when having the sheet material P of high rigidity as ground paper etc., surface of contact and noncontact face between sheet material P and the roller surface clearly manifest, and therefore, brightness disproportionation take place more significantly.
Broad ways is arranged a plurality of rollers 502, by each edge part of roller 502 sheet material P is strengthened.Therefore, stay the vestige of roller on the sheet material P by the thermal softening of bight the time of roller 502 by photographic fixing.
In addition, the sheet material of US communique 2007/0201892 and Fig. 7 is discharged parts 350 and is produced following problem.
As shown in Figure 7, sheet material discharge parts 350 by the sheet material distributing roller to constituting, this sheet material distributing roller is to comprising the diameter with homogeneous and being that the sheet material of straight-through roller (through roller) continuous on the Width of sheet material P is discharged driven roller 503 and sheet material is discharged driven voller 504.Sheet material is discharged the downstream that pallet 60 is disposed in sheet material deliverying unit 50.
As shown in Figure 7, the sheet material distributing roller is that to have the straight-through roller of homogeneous external diameter on the whole length of Width right to 505, and the sheet material distributing roller does not have the function that sheet material P is strengthened to 505.Thereby as follows sheet material P1 is discharged to sheet material and discharges on the pallet 60: leading section Pa is roughly discharged 505 point-blank with respect to the sheet material distributing roller, discharges sheet material P1 in the mode of curling along sheet material discharge direction simultaneously.At this moment, press the mode of discharging and be stacked on the sheet material P0 on the sheet material discharge pallet 60 with the whole zone (dashed region among Fig. 7) of leading section Pa and discharge sheet material P1 in the direction of arrow A with respect to sheet material P0.Therefore, the sliding resistance between sheet material P1 and the sheet material P0 increases, and can release sheet material P0 in the direction of arrow B.In addition, because the character of surface of sheet material P or the little burr that produces in the end of sheet material P when cutting off sheet material P, the leading section Pa of sheet material P1 may be stopped by sheet material P0 and discharge on the pallet 60 curling at sheet material.Thereby, can not normally discharge subsequently the sheet material that is discharged from, and very likely sheet material P1 be shifted onto the outside that sheet material is discharged pallet 60, paperboard perhaps takes place easily, cause extremely deterioration of sheet material discharging performance.
In addition, because the sheet material distributing roller is to 505 material difference, between the front and back of sheet material P1, be different to the heat of the 505 sheet material P1 that derive by the sheet material distributing roller, thus, being contracted between the front and back of sheet material P1 during sheet material P1 cooling is different, thereby sheet material may curl.
Make the present invention in view of the above problems, the invention provides a kind of sheet discharging apparatus, this sheet discharging apparatus can strengthen the rigidity of sheet material on sheet material discharge direction, the posture of stable sheet material of discharging, and the raising of the stacking performance (loadingperformance) of the sheet material of realization discharge.
Summary of the invention
The invention provides a kind of sheet discharging apparatus, this sheet discharging apparatus comprises: sheet-stacking portion, stacking sheet material in this sheet-stacking portion; And the sheet material distributing roller is right, and this sheet material distributing roller will be to will photographic fixing having the sheet material of toner image to be discharged in the sheet-stacking portion by heating as follows: make sheet material be U font curve on the Width vertical with the right discharge direction of sheet material distributing roller.
Each roller of sheet material distributing roller centering includes the rotation axis that extends on Width, elastic layer is set on the rotation axis and to form the width of the maximum sized sheet material that specific energy is passed through on Width continuously long, and at least one right elastic layer of sheet material distributing roller is formed by expanded material.
The present invention also provides a kind of image forming apparatus, and it comprises: image forming part, and this image forming part forms toner image; Photographic fixing portion, this photographic fixing portion is by heating toner image to sheet material; And sheet discharging apparatus, this sheet discharging apparatus is discharged by the sheet material of photographic fixing portion, and wherein, sheet discharging apparatus comprises: sheet-stacking portion, stacking sheet material in this sheet-stacking portion; And the sheet material distributing roller is right, and this sheet material distributing roller will be to will photographic fixing having the sheet material of toner image to be discharged in the sheet-stacking portion by heating as follows: make sheet material be U font curve on the Width vertical with the right discharge direction of sheet material distributing roller; Wherein, each roller of sheet material distributing roller centering includes the rotation axis that extends on Width, elastic layer is set on the rotation axis and to form the width of the maximum sized sheet material that specific energy is passed through on Width continuously long, and at least one right elastic layer of sheet material distributing roller is formed by expanded material.
According to the present invention, the sheet material distributing roller is to having elastic layer.The sheet material distributing roller on Width with convex (U font curve) clamping and discharge sheet material, thus, the rigidity that sheet material is discharged on the direction at sheet material increases, the stable posture of the sheet material of discharge, and improved the loading performance of the sheet material of discharging.Contacted by elastic layer, at least one right elastic layer of sheet material distributing roller is formed by expanded material with making sheet material and roller uniform surface, thereby, when image to sheet material the time, can be prevented brightness disproportionation by photographic fixing.In addition, because the bight of roller does not contact with sheet material, therefore, prevented from sheet material, to stay the vestige of roller.
By following (with reference to the accompanying drawing) explanation to exemplary embodiment, it is obvious that further feature of the present invention will become.
Description of drawings
Fig. 1 is the cut-open view of structure that the image forming apparatus of first embodiment of the invention is shown;
Fig. 2 is the enlarged side view that the structure of sheet material deliverying unit when the downstream of the throughput direction of sheet material is observed is shown;
Fig. 3 is the schematic perspective view that the structure of sheet material deliverying unit and sheet material discharge pallet is shown;
Fig. 4 is the enlarged side view that the structure of the sheet material deliverying unit that uses image forming apparatus second embodiment of the invention when the downstream of the throughput direction of sheet material is observed is shown;
Fig. 5 is the cut-open view that the structure of existing image forming apparatus is shown;
Fig. 6 is the enlarged side view that the structure of existing sheet material deliverying unit is shown;
Fig. 7 is the schematic perspective view that the structure of existing sheet material deliverying unit and existing sheet material discharge pallet is shown.
Embodiment
First embodiment
Fig. 1 is the cut-open view of structure that the image forming apparatus 100 of first embodiment of the invention is shown.This image forming apparatus 100 is the coloured image forming devices that adopt electrophotographic image formation method.
As shown in Figure 1, image forming apparatus 100 comprises image forming part 1a that is used to form yellow image and the image forming part 1b that is used to form magenta color image.Image forming apparatus 100 also comprises the image forming part 1c that is used to form cyan image and is used to form the image forming part 1d of black image.Image forming apparatus 100 comprises this four image forming parts (image formation unit).With certain interval these four image forming part 1a, 1b, 1c and 1d are configured to a row. Image forming part 1a, 1b, 1c and 1d comprise drum type Electrophtography photosensor (hereinafter referred to as photosensitive drums) 2a, 2b, 2c and the 2d as the image bearing member that forms visual image respectively.Around each photosensitive drums 2a, 2b, 2c and 2d, be provided with: charger 3a, 3b, 3c and 3d; Developing apparatus 4a, 4b, 4c and 4d; And drum cleaning device 5a, 5b, 5c and 5d.Exposure device 6 is set below image forming part 1a, 1b, 1c and 1d.Developing apparatus 4a, 4b, 4c and 4d contain Yellow toner, magenta toner, cyan toner and black toner respectively.
Each Fang Jun among photosensitive drums 2a, 2b, 2c and the 2d is the electronegative OPC photoreceptor that has optical conductive layer on drum basal body made of aluminum, by the driver (not shown) along the direction of arrow (clockwise direction) with predetermined process speed rotating drive photosensitive drums.By the charging bias voltage that applies from charging grid bias power supply (not shown) the surface of photosensitive drums 2a, 2b, 2c and 2d is charged as equably the predetermined potential of negative polarity as charger 3a, 3b, 3c and the 3d of charging unit.The electrostatic latent image that developing apparatus 4a, 4b, 4c and 4d are attached to each colour toners to be formed at photosensitive drums 2a, 2b, 2c and 2d is being toner image with this latent electrostatic image developing (visual).The developing method that is undertaken by developing apparatus 4a, 4b, 4c and 4d comprises that bi-component contacts developing method.In this developing method, contain the developer of the magnetic carrier that mixes with toner particle by the magnetic force conveying, and under developer and photosensitive drums 2a, 2b, 2c and 2d state of contact, carry out image developing.
Constitute by elastic component as primary transfer roller 34a, 34b, 34c and the 34d of transfer member, and primary transfer roller 34a, 34b, 34c and 34d in each transfer nip portion across endless belt-shaped intermediate transfer belt 31 and photosensitive drums 2a, 2b, 2c and 2d butt.In this embodiment, primary transfer roller 34a, 34b, 34c and 34d are used as transfer member; Yet, also can use when toner image is transferred to transfer materials, bear high pressure and with the transfer printing blade of intermediate transfer belt 31 butts.
In exposure device 6, the laser beam of modulating from the electric digital pixel signal of time series of laser efferent (not shown) output response image information.Exposure device 6 exposes to the surface of photosensitive drums 2a, 2b, 2c and 2d by for example polygonal mirror (not shown) with high-speed rotation.According to this structure, on the surface that is recharged device 3a, 3b, 3c and 3d charging of photosensitive drums 2a, 2b, 2c and 2d, form the of all kinds electrostatic latent image corresponding with image information.
Sheet material supply unit 20 comprises sheet material box 21, as the box conveying roller 22 of delivery section, as registration roller (registration roller) 23a and 23b, manual feed trays conveying roller 24 and the manual feed trays 71 of delivery section.Sheet material supply unit 20 select in the sheet material boxes 21 or the sheet material P on the manual feed trays 71 carrying selected sheet material P, and this sheet material P is transported to the Te of secondary transfer printing portion as transfer printing portion.The Te of secondary transfer printing portion will be transferred to sheet material P by the visual image that image forming part 1a, 1b, 1c and 1d form.
In intermediate transfer unit 30, intermediate transfer belt 31 is tightened up between driven roller 32 and jockey pulley 33, drives intermediate transfer belt 31 so that intermediate transfer belt 31 rotates (motion) along the direction of arrow (counterclockwise) by driven roller 32.Intermediate transfer belt 31 is by forming as insulating resins such as polycarbonate, pet resin film or polyvinylidene fluoride resin films.In addition, intermediate transfer belt cleaning device 80 is set at across the position of intermediate transfer belt 31 in the face of jockey pulley 33.Intermediate conveyor belt cleaning device 80 comprises cleaning balde 81 and conveying screw rod 82, this cleaning balde 81 is formed by the elastic body with predetermined pressure and intermediate transfer belt 31 butts, and this conveying screw rod 82 is carried the residual toner of being removed from middle transfer belt 31 by cleaning balde 81.By conveying screw rod 82 residual toner is transported to toner collection container (not shown).
Then, illustrate that the image that is undertaken by image forming apparatus 100 forms operation.When sending image and form commencing signal, by charger 3a, 3b, 3c and 3d make image forming part 1a, 1b, 1c and 1d to be rotated photosensitive drums 2a, 2b, 2c and the 2d of driving with predetermined process speed electronegative equably.Then, exposure device 6 is converted to optical signalling by means of laser efferent (not shown) with the picture signal of output image.As by the laser beam of changing the optical signalling that obtains each surface of charged photosensitive drums 2a, 2b, 2c and 2d being scanned and being exposed to form electrostatic latent image.
Subsequently, make the electrostatic latent image that is formed on the photosensitive drums 2a at first adhere to Yellow toner, and to make this latent electrostatic image developing be toner image by the developing apparatus 4a that is applied in development bias voltage with polarity (negative polarity) identical with the charged polarity of photosensitive drums 2a.Then, at primary transfer portion Ta place yellow toner image is transferred to intermediate transfer belt 31 by the primary transfer roller 34a that is applied in transfer bias (polarity opposite (positive polarity)) with toner.
Make transfer printing have the intermediate transfer belt 31 of yellow toner image to move to image forming part 1b by driven roller 32.Similarly, at the primary transfer portion Tb place that constitutes by image forming part 1b and primary transfer roller 34b, to be formed on magenta toner image overlay on the photosensitive drums 2b on the yellow toner image on the intermediate transfer belt 31 by above-mentioned same method, then this magenta toner image of transfer printing.Thereafter, similarly, be superimposed upon in turn to have superposeed at the Tc of primary transfer portion and Td and be transferred on the yellow and magenta toner image on the intermediate transfer belt 31 being respectively formed at the photosensitive drums 2c of image forming part 1c and 1d and the cyan toner image on the 2d and black toner image.According to this formation, on intermediate transfer belt 31, form full-color toner image.
Timing when moving to the Te of secondary transfer printing portion according to the front end of the toner image on the intermediate transfer belt 31 will be transported to the Te of secondary transfer printing portion from the sheet material P that sheet material box 21 or manual feed trays 71 are carried by registration roller 23a and 23b.Then, by the secondary transfer roller 36 that is applied in transfer bias (polarity opposite (positive polarity)) full-color toner image is transferred on the sheet material P that is transported to the Te of secondary transfer printing portion with toner.
The sheet material P that is formed with full-color toner image is transported to the fixation unit 40 as photographic fixing portion, and this photographic fixing portion is the image heat fixing device.By the fusing nip between fixing roller 42 and the backer roll 41 full-color toner image is heated and pressurize with full-color toner image hot photographic fixing after the surface of sheet material P, by sheet material deliverying unit 50 sheet outside that sheet material P is discharged to the equipment of being arranged at is discharged in the pallet 60, finish a series of images thus and form operation.
Fig. 2 is the enlarged side view that the structure of sheet material deliverying unit 50 when the downstream of the throughput direction of sheet material P is observed is shown.As shown in Figure 2, comprise that as the sheet material deliverying unit 50 of sheet discharging apparatus the sheet material distributing roller is right, this sheet material distributing roller is to comprising sheet material and discharge driven roller 51 and sheet material being discharged driven voller 52.Sheet material discharge driven roller 51 is corresponding with a sheet material distributing roller.Sheet material discharge driven voller 52 is corresponding with another sheet material distributing roller.Sheet material is discharged the driving force that driven roller 51 transmits the drive source (not shown).Sheet material discharge driven voller 52 is discharged driven roller 51 in the face of sheet material, and 52 pairs of sheet materials discharges of sheet material discharge driven voller driven roller 51 is exerted pressure with bias voltage sheet material discharge driven roller 51.Sheet material deliverying unit 50 by sheet material discharge driven roller 51 and sheet material discharge driven voller 52 rotation will photographic fixing has the sheet material P of toner image to be discharged to the outside of image forming apparatus main body 100a by fixation unit 40 and by heating.
Sheet material is discharged driven roller 51 and is comprised as the metal shaft 51b of rotation axis and be arranged on elastic layer 51a on the metal shaft 51b.Elastic layer 51a uses for example polyurethane, NBR and EPDM here by as the forming as resin materials such as foam rubbery material or foaming elastomers of expanded material.In this case, for clamping and feeding sheets reliably, the hardness of elastomeric material is preferably 20 to 60 (when measuring hardness by Asker C sclerometer).Sheet material is discharged driven roller 51 and is connected to the drive source (not shown) and constitutes driven roller rotationally.On the direction of metal shaft 51b, forming elastic layer 51a continuously.
In addition, sheet material is discharged driven voller 52 and is comprised as the metal shaft 52b of rotation axis and be arranged on elastic layer 52a on the metal shaft 52b.To discharge driven roller 51 the same with sheet material, and the elastic layer 52a of sheet material discharge driven voller 52 uses for example polyurethane, NBR and EPDM here by as the forming as resin materials such as foam rubbery material or foaming elastomers of expanded material.At least one elastic layer that sheet material is discharged driven roller 51 and sheet material discharge driven voller 52 can be formed by expanded material, be stacked on the sheet material discharge pallet 60 with flexibility from the total amount of heat minimizing and the sheet material P of sheet material P derivation, the sheet material P's of minimizing discharge is curling thus.In addition, preferred sheet material is discharged driven voller 52 and is formed by discharging driven roller 51 identical materials with sheet material or having the material of discharging the identical temperature conductivity of the temperature conductivity of driven roller 51 with sheet material, to reduce the curling of the sheet material P that discharges.In addition, as discharging at sheet material in the driven roller 51 like that, for clamping and feeding sheets reliably, the hardness that sheet material is discharged the elastomeric material of driven voller 52 is preferably 20 to 60 (when by Asker C sclerometer measurement hardness).On the direction of metal shaft 52b, forming elastic layer 52a continuously.Sheet material is discharged driven voller 52 and is comprised the pressing spring 54 that is arranged in the two ends of metal shaft 52b via bearing 53, and 54 pairs of sheet materials discharges of pressing spring driven roller 51 applies predetermined pressure.The pressure that is applied to sheet material discharge driven roller 51 of pressing spring 54 preferably is set to about 0.1kg to 1kg, thereby can guarantee the transportation performance to sheet material P.
The elastic layer 51a of sheet material discharge driven roller 51 has the roughly symmetrical shape of center line a about the central authorities of the Width of sheet material P.Elastic layer 51a is made of (straight portion) 61 of straight portion and tapering (taper portion) 62, straight portion 61 is the constant cylindrical portion of external diameter, and the reduction (taper amount) that tapering 62 has from the both ends of straight portion 61 to the both ends of elastic layer 51a is the tapered shape of d1.The zone of center line a is called as the central portion that sheet material is discharged driven roller 51 at least.The zone of the straight portion 61 also central portion with sheet material discharge driven roller 51 is corresponding.Discharge among the elastic layer 51a of driven roller 51 at sheet material, the outer diameter D 1 of central portion is set to greater than the outer diameter D 2 as the both ends 62a at the both ends on the Width.
When the axial length L of straight portion 61 was oversize, the effect of the difference D1-D2 of the outer diameter D 1 of the straight portion 61 of elastic layer 51a and the outer diameter D 2 of both ends 62a may reduce.On the other hand,, then keep the balance of sheet material P may be destroyed vertically, cause the crooked feeding of sheet material P thus or may not discharge normally if length L is too short.Thereby the axial length L of straight portion 61 is preferably greater than 0 and be less than or equal to 1/3 of length L 1 (referring to Fig. 3) on the Width of the maximum sized sheet material P that can pass through.That is to say, preferably set up 0＜L≤1/3L1.
Fig. 3 is the schematic perspective view that the structure of sheet material deliverying unit 50 and sheet material discharge pallet 60 is shown.As shown in Figure 3, sheet material is discharged the downstream along the direction of passage of sheet material P that pallet 60 is disposed in sheet material deliverying unit 50.In this case, when sheet material P is discharged from, can be regardless of the size of sheet material P, and with guide center feeding sheets P.
According to the sheet material deliverying unit 50 of present embodiment, has difference: D1-D2 between the outer diameter D 1 of the straight portion 61 of sheet material discharge driven roller 51 and the outer diameter D 2 of both ends 62a.Therefore, the peripheral speed of sheet material discharge driven roller 51 is being different between straight portion 61 and both ends 62a.When the peripheral speed of straight portion 61 was high, the peripheral speed of each among the 62a of both ends was lower than the peripheral speed of straight portion 61.Thereby the sheet material efflux velocity of the sheet material P that has discharged is different between central portion Pb and both ends Pc.Shown in the arrow C among Fig. 3, to discharge the central portion Pb of the leading section of sheet material P than the fast speed of the both ends Pc of the leading section of sheet material P, the central portion Pb of leading section that makes sheet material P thus is than early discharge of both ends Pc of the leading section of sheet material P.Because the both ends Pc of the leading section of the central portion Pb pulling-on piece material P of the leading section of sheet material P, therefore, the shape that both ends Pc follows tapering 62 is discharged from the state that lifts a little.Thereby, when sheet material P1 is discharged from, has only when the central portion Pb of the leading section of sheet material P1 is in having discharged and discharge sheet material P0 state of contact following time on the pallet 60 at sheet material and could discharge the leading section of sheet material P1.
As mentioned above, image forming apparatus 100 according to first embodiment, it is that the center is mutually symmetrical basically that the external diameter of the elastic layer 51a of sheet material discharge driven roller 51 forms with the central portion on the Width of sheet material P, and the outer diameter D 1 of straight portion 61 is set to the outer diameter D 2 greater than both ends 62a.Elastic layer 51a has the level and smooth tapered shape from straight portion 61 to both ends 62a.Thereby, the efflux velocity of the sheet material P in the straight portion 61 is set at height, the efflux velocity among the 62a of both ends is set at less than the efflux velocity in the straight portion 61.Therefore, by the sheet material distributing roller to downwards and convex (U font curve) clamping that both ends Pc upwards raises a little and discharge sheet material P with the central portion Pb of the leading section of sheet material P on the Width vertical with the right discharge direction of sheet material distributing roller.Constitute according to this, can improve sheet material and discharge rigidity on the direction at sheet material, and can reduce the front end of the sheet material P1 that discharges as much as possible and the sheet material P0 that discharged between the size of contact area.Therefore, the sheet material P0 that discharged of the sheet material P1 that can prevent to discharge stops and problem that sheet material P0 is released.In addition, prevented paperboard.In addition, can improve discharging performance and the loading performance of the sheet material P of discharge.In addition, can prevent following phenomenon as much as possible: curl owing to being discharged to that sheet material is discharged the character of surface of the sheet material P on the pallet 60 or when cutting off sheet material P, causing the leading section of the sheet material P that discharges to be stopped at the little burr of the end of sheet material P generation.Can be by the sheet material distributing roller to reverse gibbous shape (reverse U shape curve) clamping and discharge sheet material P and discharge rigidity on the direction at sheet material to improve sheet material.
The outer circumferential side that sheet material is discharged driven roller 51 and sheet material discharge driven voller 52 has elastic layer respectively, thus, discharge between the driven voller 52 and to make sheet material P discharge driven roller 51 and sheet material when discharging between the driven voller 52 by sheet material when sheet material P pressurizeed when discharge driven roller 51 and sheet material at sheet material, sheet material is discharged the straight portion 61 of driven roller 51 can be according to the thickness of sheet material P and depression flexibly.Elastic layer 51a can contact equably with sheet material P.Constitute according to this, discharge driven roller 51 and sheet material by sheet material and discharge the heat of the toner on the sheet material P that derives on the surface of driven voller 52 and do not have difference, thereby, the generation of brightness of image inequality can be prevented.
The external diameter of straight portion 61 is discharged driven roller 51 greater than the sheet material of the external diameter of both ends 62a and is disposed in the top that sheet material is discharged driven voller 52.Thereby, discharge sheet material P by pushing sheet material P from the middle position of the Width of the upper surface of sheet material P.Therefore, when sheet material P discharged between driven roller 51 and the sheet material discharge driven voller 52 by sheet material, sheet material P was discharged under the state that is curled into the U word shape easily.The sheet material P0 that middle position on the Width of the sheet material P1 that discharges has been discharged hardly stops.On the other hand, discharge in the driven voller 52 if straight portion 61 and tapering 62 are formed on sheet material, then sheet material P may be inconvenient to be discharged under the state that is curled into the reverse U shape shape.
Since the length of straight portion 61 be equal to or less than the maximum sized sheet material P that can pass through Width length L 1 1/3, therefore, suitably kept sheet material to discharge the holding force that is used for sheet material P that driven roller 51 and sheet material are discharged driven voller 52.When using when having the sheet material P of high rigidity as ground paper etc., the whole zone on the Width of clamping sheet material P reliably.Therefore, can prevent brightness disproportionation.If the length of straight portion 61 surpass the sheet material P that can pass through breadth extreme 1/3, then between straight portion 61 on the Width of sheet material P and both ends 62a, produce the difference of efflux velocity hardly.When straight portion 61 is not set, keep the balance of sheet material P may be destroyed vertically, cause the crooked feeding of sheet material P thus or may not discharge normally.
As mentioned above, first embodiment of the invention, based on simple formation, image forming apparatus 100 can be when keeping high-quality print image and strengthening the discharging performance of sheet material P reduced in size and cost.
Much less, this embodiment is not limited to the toning system and the transferring system that use in the described image forming apparatus of this embodiment, and is also effectively general for the discharger of image forming apparatus.
Second embodiment
Fig. 4 is the enlarged side view that the structure of the sheet material deliverying unit 150 that uses image forming apparatus second embodiment of the invention when the downstream of the throughput direction of sheet material P is observed is shown.The difference of the sheet material deliverying unit 50 of the sheet material deliverying unit 150 and first embodiment is to use sheet material to discharge driven roller 151 replacement sheet materials and discharges driven roller 51.In sheet material deliverying unit 150, represent parts and the effect identical with effect with identical Reference numeral, and suitably omit its explanation with the parts of sheet material deliverying unit 50.In addition, in second embodiment, can use and the similar image forming apparatus of the image forming apparatus of first embodiment, thereby, explanation omitted to image forming apparatus.
As shown in Figure 4, sheet material deliverying unit 150 is made of sheet material discharge driven roller 151 and sheet material discharge driven voller 52.Sheet material is discharged driven roller 151 by constituting as the metal shaft 51b of rotation axis and the elastic layer 151a that is wrapped on the metal shaft 51b.What elastic layer 151a had that central portion on the Width of sheet material P has a maximum outside diameter D1 bloats shape (crown shape).Elastic layer 151a is formed by the foam rubbery material as expanded material, uses for example polyurethane, NBR and EPDM here.In this case, for clamping and feeding sheets P reliably, the hardness of elastomeric material is preferably 20 to 60 (when measuring hardness by Asker C sclerometer).Sheet material is discharged driven roller 151 and is connected to the drive source (not shown) and constitutes driven roller rotationally.
In addition, sheet material discharge driven voller 52 is made of metal shaft 52b and the elastic layer 52a that is wrapped on the metal shaft 52b.As discharging in the driven roller 151 at sheet material, the elastic layer 52a that sheet material is discharged driven voller 52 is formed by foam rubbery material, uses for example polyurethane, NBR and EPDM here.In addition, preferred sheet material is discharged driven voller 52 and is formed by discharging driven roller 151 identical materials with sheet material or having the material of discharging the identical temperature conductivity of the temperature conductivity of driven roller 151 with sheet material.In addition, as discharging in the driven roller 151 at sheet material, the hardness that sheet material is discharged the elastomeric material of driven voller 52 is preferably 20 to 60 (when measuring hardness by Asker C sclerometer).Sheet material is discharged driven voller 52 and is comprised the pressing spring 54 that is arranged in the two ends of metal shaft 52b via bearing 53, and 54 pairs of sheet materials of pressing spring are discharged driven roller 151 and applied predetermined pressure.The pressure that is applied to sheet material discharge driven roller 151 of pressing spring 54 preferably is set to about 0.1kg to 1kg, thereby can guarantee the transportation performance of sheet material P.
The elastic layer 151a of sheet material discharge driven roller 151 has the shape about the center line a substantial symmetry of the central authorities on the Width of sheet material P, and profile is that the slyness with the amount of bloating d2 bloats shape.
The image forming apparatus of second embodiment can obtain the situation similar effects with first embodiment.The central portion that the elastic layer 151a of sheet material discharge driven roller 151 has on the Width of sheet material P has the shape that bloats of maximum outside diameter D1.Therefore, as additional effect, sheet material discharge driven roller 151 elastic layer 151a can according to sheet material P on the Width of sheet material P shape and distortion glibly.
Should note, can the above-mentioned formation of following change: the sheet material of first and second embodiments discharge driven roller 51 and 151 and sheet material discharge among elastic layer 51a, the 151a and 52a of driven voller 52, tubular resin film can be wrapped on the periphery of the printing surface side that is arranged in sheet material of at least one side among elastic layer 51a, 151a and the 52a.According to this formation, even toner fully is not fused to sheet material P in fixation unit 40, elastic layer 51a, 151a and 52a can prevent that also toner is removed.
The hardness of the sheet material discharge driven roller 51 of first and second embodiments and 151 elastic layer 51a, 151a can be set to and be higher than the hardness that sheet material is discharged the elastic layer 52a of driven voller 52.Constitute according to this, the hardness that each sheet material is discharged elastic layer 51a, the 151a of driven roller 51 and 151 is higher than the hardness that sheet material is discharged the elastic layer 52a of driven voller 52.Thereby, can prevent that elastic layer 51a, the 151a of sheet material discharge driven roller 51 and 151 from being driven the phenomenon that distributing roller 52 grinds by sheet material.Therefore, keep sheet material to discharge outer diameter D 2 poor of the outer diameter D 1 of the straight portion 61 in the driven roller 51 and 151 and both ends 62a: D1-D2 for a long time.
In addition, in first embodiment and second embodiment, sheet discharging apparatus according to the present invention is included in the image forming; Yet sheet discharging apparatus also can be the reorganizer (finisher) that can connect from the outside of image forming apparatus.
Though with reference to exemplary embodiment the present invention has been described,, should be appreciated that, the invention is not restricted to disclosed exemplary embodiment.The scope of appended claims will meet the wideest explanation, to comprise all modification, equivalent structure and function.
The application requires the right of priority of Japanese patent application No.2008-201811 that submitted on August 5th, 2008 and the Japanese patent application No.2009-162516 that submitted on July 9th, 2009, and the full content of this Japanese patent application is contained in this by reference.
Claims (14)
1. sheet discharging apparatus, it comprises:
Sheet-stacking portion, stacking sheet material in this sheet-stacking portion; And
The sheet material distributing roller is right, this sheet material distributing roller to as follows will be by heating photographic fixing have the sheet material of toner image to be discharged in the described sheet-stacking portion: make described sheet material on the Width vertical, be U font curve with the right discharge direction of described sheet material distributing roller;
Wherein, each roller of described sheet material distributing roller centering includes the rotation axis that extends on described Width, elastic layer is set on the described rotation axis and to form the width of the maximum sized sheet material that specific energy is passed through on described Width continuously long, and at least one right elastic layer of described sheet material distributing roller is formed by expanded material.
2. sheet discharging apparatus according to claim 1, it is characterized in that, a sheet material distributing roller of described sheet material distributing roller centering at the external diameter of the central portion on the described Width external diameter greater than the both ends on described Width of this sheet material distributing roller.
3. sheet discharging apparatus according to claim 2 is characterized in that, a described sheet material distributing roller is disposed in the top of another sheet material distributing roller of described sheet material distributing roller centering.
4. according to claim 2 or 3 described sheet discharging apparatus, it is characterized in that, the central portion of described elastic layer on described Width of a described sheet material distributing roller has the constant cylindrical portion of external diameter, the length L of described cylindrical portion is 0＜L≤1/3L1, wherein, L1 be can by described sheet material distributing roller between the length of maximum sized described sheet material on described Width, described elastic layer have from described cylindrical portion at the two ends on the described Width to the tapered shape in the two ends on described Width of a described sheet material distributing roller.
5. according to claim 2 or 3 described sheet discharging apparatus, it is characterized in that the central portion that the described elastic layer of a described sheet material distributing roller has on the Width of described sheet material has the shape that bloats of maximum outside diameter.
6. according to claim 2 or 3 described sheet discharging apparatus, it is characterized in that the hardness of the described elastic layer of a described sheet material distributing roller is higher than the hardness of elastic layer of another sheet material distributing roller of described sheet material distributing roller centering.
7. according to each described sheet discharging apparatus in the claim 1 to 3, it is characterized in that, twine tubular resin film on the periphery of the printing surface side that is arranged in described sheet material of at least one elastic layer in the right described elastic layer of described sheet material distributing roller.
8. image forming apparatus, it comprises:
Image forming part, this image forming part forms toner image;
Photographic fixing portion, this photographic fixing portion is by heating described toner image to sheet material; And
Sheet discharging apparatus, this sheet discharging apparatus are discharged the described sheet material by described photographic fixing portion,
Wherein, described sheet discharging apparatus comprises:
Sheet-stacking portion, stacking sheet material in this sheet-stacking portion; And
The sheet material distributing roller is right, this sheet material distributing roller to as follows will be by heating photographic fixing have the sheet material of toner image to be discharged in the described sheet-stacking portion: make described sheet material on the Width vertical, be U font curve with the right discharge direction of described sheet material distributing roller; Wherein, each roller of described sheet material distributing roller centering includes the rotation axis that extends on described Width, elastic layer is set on the described rotation axis and to form the width of the maximum sized sheet material that specific energy is passed through on described Width continuously long, and at least one right elastic layer of described sheet material distributing roller is formed by expanded material.
9. image forming apparatus according to claim 8, it is characterized in that, a sheet material distributing roller of described sheet material distributing roller centering at the external diameter of the central portion on the described Width external diameter greater than the both ends on described Width of this sheet material distributing roller.
10. image forming apparatus according to claim 9 is characterized in that, a described sheet material distributing roller is disposed in the top of another sheet material distributing roller of described sheet material distributing roller centering.
11. according to claim 9 or 10 described image forming apparatus, it is characterized in that, the central portion of described elastic layer on described Width of a described sheet material distributing roller has the constant cylindrical portion of external diameter, the length L of described cylindrical portion is 0＜L≤1/3L1, wherein, L1 be can by described sheet material distributing roller between the length of maximum sized described sheet material on described Width, described elastic layer have from described cylindrical portion at the two ends on the described Width to the tapered shape in the two ends on described Width of a described sheet material distributing roller.
12. according to claim 9 or 10 described image forming apparatus, it is characterized in that,
The central portion that the described elastic layer of a described sheet material distributing roller has on the Width of described sheet material has the shape that bloats of maximum outside diameter.
13., it is characterized in that the hardness of the described elastic layer of a described sheet material distributing roller is higher than the hardness of elastic layer of another sheet material distributing roller of described sheet material distributing roller centering according to claim 9 or 10 described image forming apparatus.
14. each described sheet discharging apparatus in 10 is characterized in that according to Claim 8, twines tubular resin film on the periphery of the printing surface side that is arranged in described sheet material of at least one elastic layer in the right described elastic layer of described sheet material distributing roller.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008201811 | 2008-08-05 | ||
| JP2008201811 | 2008-08-05 | ||
| JP2009162516 | 2009-07-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101644905A true CN101644905A (en) | 2010-02-10 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910161910A Pending CN101644905A (en) | 2008-08-05 | 2009-08-05 | Sheet discharging device and image forming apparatus including the sheet discharging device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101644905A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104756018A (en) * | 2012-10-30 | 2015-07-01 | 佳能株式会社 | Sheet processing apparatus and image forming system |
| CN105045074A (en) * | 2014-04-30 | 2015-11-11 | 佳能株式会社 | Sheet conveying apparatus and image forming apparatus |
-
2009
- 2009-08-05 CN CN200910161910A patent/CN101644905A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104756018A (en) * | 2012-10-30 | 2015-07-01 | 佳能株式会社 | Sheet processing apparatus and image forming system |
| CN105045074A (en) * | 2014-04-30 | 2015-11-11 | 佳能株式会社 | Sheet conveying apparatus and image forming apparatus |
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Open date: 20100210 |