CN2755646Y

CN2755646Y - Fixing device and imager therewith

Info

Publication number: CN2755646Y
Application number: CN 200420066874
Authority: CN
Inventors: 有贺友卫; 井熊健
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2003-06-20
Filing date: 2004-06-21
Publication date: 2006-02-01
Anticipated expiration: 2014-06-21
Also published as: JP2005010609A

Abstract

The utility model discloses an image fixing apparatus used for the image fixing of the non-fixation toner image formed on the sheet recording medium. A first roller comprises a heat source, and a second roller is pressed to the first roller. One part of an endless belt is wound on the periphery of the second roller to be rotated in an annular mode. An unable rotating belt tension device and the second roller together tighten the endless belt. In this way, the endless belt rotated in an annular mode slides along the first side of the transverse extension of the endless belt and the two lateral end parts of the endless belt are applied by the tension. The endless belt rotated in an annular mode is clamped between the first roller and the second roller to form a roller gap part. The image of the non-fixation toner image passes through the first roller gap part and is fixed to the recording medium under the heat action of the heat source. The first side is bent along the transverse direction.

Description

Fixation facility and the imaging device that comprises it

Technical field

The utility model relates to the fixation facility that makes the unfixed toner image photographic fixing that forms on sheet medium.Described fixation facility comprises: warm-up mill; Push down the backer roll of warm-up mill; By outer rim of twining backer roll and the band of nipping and moving between backer roll and the warm-up mill; With the belt tightener that is tensioned thereon of band.The utility model also relates to the imaging device that comprises a kind of like this fixation facility.

Background technology

Imaging device such as duplicating machine, Printers and Faxes machine comprises the fixation facility that heats roll-type, in this equipment, the unfixing toner on the recording medium heating the time be stressed contact and with the unfixing toner photographic fixing to recording medium.This fixation facility comprises: have the rotatable warm-up mill that elastomer coating also holds thermal source therein in its surface; The band of tensioning on a plurality of backing rolls; And pressure-producing part, form roll-gap region by making band twine warm-up mill with predetermined angle, apply the pressure bigger by outlet part simultaneously and make the distortion of the lip-deep elastic body of warm-up mill, make thus that sheet medium is easier to discharge from roll-gap region than other parts to roll-gap region.A kind of like this structure is disclosed in Jap.P. No.3084692.

In fixation facility, the surface of warm-up mill is owing to there is the existence of pressure-producing part to be out of shape in advance, and when toner lip-deep distortion of respite when contacting with warm-up mill is surperficial.Therefore, when sheet medium when roll-gap region is discharged, the contact force between toner and the warm-up mill is reduced, and twines warm-up mill to prevent sheet medium, even make that not too solid recording paper also can be in the exit of band roll gap by delamination.So this equipment has not just needed the disengaging pawl parts.

Yet, need a plurality of backing rolls and swivel bearing.In addition, not only elongated the girth of band, and fixation facility also becomes complicated, size and cost all increased.This fixation facility become complexity and the structure of increased in size and cost of making makes the imaging device that is equipped with this fixation facility also become complexity and increased in size and cost naturally.

And band partly locates to be received the rotatable warm-up mill heating of thermal source at roll gap; But, for wherein on a plurality of rollers, being tensioned and structure that its girth is elongated inevitably, when heat energy when predefined paths moves is absorbed by a plurality of backing rolls at band.In addition, the heat of nature discharges increases with girth.This has prolonged the required time of predetermined temperature that reaches, from and prolonged to be activated and can carry out photographic fixing operation required so-called preheating time from device.Therefore, this structure is not preferred.

In addition, in this structure, be by will be with twining warm-up mill, and apply the pressure bigger than other parts by part, exit in the roll gap part to form the required angle of roll gap, make elastic body distortion on the warm-up mill, this structure be suitable for preventing that sheet medium from twining warm-up mill; But owing to curling along distortion or because of the partial high pressure wrinkle, the sheet medium of discharging along elastomeric distortion just has been twisted.

The open No.6-40235B of Jap.P. discloses a kind of fixation facility, and wherein unfixed toner image is by being passed in the roll-gap region that forms between the roller part that is subjected to press contacts each other, and by photographic fixing on recording medium.In this equipment, the rotational speed of roller part can be configured to meet first speed or the second speed of recording medium characteristics.

But,, prolonged preheating time because the thermal capacity of roller part is very big.And, pass by make the recording medium of the roll-gap region that roller part forms with pressure, owing to very big being distorted of applied stress that this pressure caused, for example curl and wrinkle.

The open No.8-262903A of Jap.P. discloses a kind of fixation facility, wherein, on the warm-up mill endless belt of tensioning be driven when warm-up mill contacts, and described warm-up mill has elastomer coating in its surface and hold thermal source therein, and be positioned at the inboard, endless belt, the endless belt is pressed in non-rotatable pressure pad on the warm-up mill, not only form the roll gap part, also make in the lip-deep elastic body distortion of warm-up mill.The sheet medium of carrying unfixed toner image is compelled to pass space between warm-up mill and the endless belt so that toner by photographic fixing on sheet medium.Because pressure pad is not rotated, the heat of coming from the warm-up mill transmission dissipates hardly.Therefore an advantage is arranged, and promptly the heat that absorbs from warm-up mill seldom.

But, be extended preheating time, because heat is passed to pressure pad from warm-up mill via the endless belt during warm-up operation.In addition, need three or more rollers that band is changeed, this has just produced another problem that this equipment size is increased.

Summary of the invention

Therefore a purpose of the present utility model provides a kind of heating roll-type fixation facility, its simple in structure, compact and saving cost, and it can shorten preheating time, and, for example occur curling and wrinkle by reducing to be applied to the distortion that stress on the sheet medium suppresses to be discharged from sheet medium (recording medium).

In order to achieve the above object, according to the utility model, provide a kind of fixation facility, be used for the unfixed toner image photographic fixing that will be formed on the sheet-shaped recording medium, described fixation facility comprises:

First roller wherein comprises thermal source;

Second roller is pressed towards described first roller;

Endless belt, its part are wrapped on the periphery of described second roller to be changeed by ring; With

Non-rotatable belt tightener, its with described second roller with the tensioning of described endless belt, so that described endless belt of being changeed by ring sliding on first of the horizontal expansion of described endless belt, and make tension force be applied to two lateral end parts of described endless belt, wherein:

Described endless belt of being changeed by ring is clamped between described first roller and described second roller to form the first roll gap part, described unfixed toner image is passed the described first roll gap part, under from the effect of the heat of described thermal source by photographic fixing on described recording medium; And

Described first laterally being bent of described belt tightener along described endless belt.

Here, make described first the transverse center part of described belt tightener partly be recessed into or protrusion from its described two lateral end.

Preferably, described endless belt of being changeed by ring is clamped between described first roller and the described belt tightener to form the second roll gap part, described unfixed toner image is passed the described second roll gap part, under from the effect of the heat of described thermal source by photographic fixing on described recording medium.

Utilize above structure, because two lateral end parts of endless belt and belt tightener first closely contacts, so the fold that can avoid the endless belt partly to locate at second roll gap.In addition, the whole length that is held that is used for recording medium can be extended to realize stable photographic fixing operation.

Here, preferably, in order to limit the vibration campaign of described endless belt of being changeed by ring, described belt tightener comprises wall components, described wall components have with described two lateral end of described endless belt partly at least one adjacent second.

In addition preferably, described wall components and described belt tightener are integrally formed.More preferably, described wall components and described belt tightener are whole forms.

Utilize above structure, can eliminate the vibration campaign of the endless belt of being changeed, make stable photographic fixing operation to be implemented by ring.

Also preferably, described second described first extension continuously of described wall components from described belt tightener.

Here, also preferably, described second of described wall components forms first angle with in the described lateral end part of described endless belt one of described belt tightener described first.Described first of the side end face of described endless belt and described belt tightener in the described lateral end part of described endless belt one forms second angle, and described second angle is less than described first angle.

Utilize above structure, can more effectively avoid being encircled the fold of lateral end part of the endless belt of commentaries on classics.

Also preferably, the height dimension of described wall components is greater than the gauge of described endless belt.

Also preferably, described wall components is formed with scarf, and described scarf extends to described second, described endless belt of being changeed by ring is directed among described first of described belt tightener.

Utilize above structure, can prevent that the endless belt of being encircled commentaries on classics from crossing wall components.

Also preferably, the part of described wall components abuts against on described first roller, partly to locate to limit the slit between described first roller and described belt tightener described first at described second roll gap.

Here, also preferably, state distance between first roller and described belt tightener described first in place, described slit greater than the gauge of described endless belt.Determine described distance, make when described recording medium enters the described second roll gap part that described first of described belt tightener is pressed in described recording medium on described first roller by described endless belt.

Utilize above structure because described slit during the warm-up operation of this device as thermofin, so just reduced the heat (being thermal losses) that absorbs from first roller via the endless belt, therefore can shorten the required time of warm-up operation.When recording medium entered the second roll gap part, described slit was eliminated, thereby can realize the stable contact between the recording medium and first roller.

Preferably, wherein said belt tightener can pivot.More preferably, elastomeric element is pushed described belt tightener to described first roller.Here, the pivot center of described belt tightener can be identical or different with the turning axle of described second roller.

Preferably, described belt tightener has from the horizontal direction of described endless belt and sees the xsect that is semi-circular or annular.

Under the situation of second roller, belt tightener can be positioned to and be positioned as close to second roller in the open side of described semi-circular cross-section.Therefore, can shorten the whole length of endless belt, make the atural beat that prolongs warm-up operation discharge and to be suppressed.In addition, this fixation facility can be made compact.

Preferably, clearer is between described second roller and described belt tightener, on the inner peripheral surface that abuts against described endless belt.

Preferably, described belt tightener is positioned on the ring veer of described endless belt upstream side or the downstream with respect to described first roll gap part.

According to the utility model, a kind of imaging device also is provided, comprising:

Imaging device, it forms toner image on recording medium; With

Above-mentioned fixation facility, it is used for the described toner image on the described recording medium.

Description of drawings

Describe its preferred example embodiment in detail by the reference accompanying drawing, above-mentioned purpose of the present utility model and advantage will be clearer, wherein:

Figure 1A is the cut-open view according to the fixation facility of the utility model first embodiment;

Figure 1B is the phantom view that the line IB-IB along Figure 1A is got;

Fig. 2 is the phantom view that the line II-II along Figure 1A is got;

Fig. 3 is the phantom view of the pressurized contact portion of belt tightener and warm-up mill in the fixation facility of Figure 1A, and it shows the state that unloads heatproof zone;

Fig. 4 is the phantom view of pressurized contact portion, and it shows the state of installing heatproof zone;

Fig. 5 is the phantom view of this pressurized contact portion, and it shows the state that sheet medium enters the pressurized contact portion;

Fig. 6 A is the enlarged diagram that is used to explain band sliding motion on belt tightener;

Fig. 6 B and 6C are the enlarged diagrams according to the belt tightener of first comparative example, and it shows the situation that occurs fold in the side edge of band;

Fig. 7 A is according to the belt tightener of second comparative example and the enlarged diagram of band;

Fig. 7 B is according to the belt tightener of the 3rd comparative example and the enlarged diagram of band;

Fig. 8 A and 8B are the enlarged diagrams of the shape of the belt tightener in the fixation facility of Figure 1A;

Fig. 8 C be in the fixation facility of Figure 1A with edge surface and the enlarged diagram of the protrusion walls of belt tightener;

Fig. 9 A illustrates the enlarged diagram that concerns between tape thickness and the protrusion walls height;

Fig. 9 B is the enlarged diagram that is illustrated in the function of the chamfered portion that forms on the protrusion walls;

Fig. 9 C is the band seen from the downside of Fig. 9 B and the plan view of protrusion walls;

Fig. 9 D is the plan view of improvement example of the protrusion walls of Fig. 9 C;

Figure 10 A is the skeleton view of the protrusion walls of Fig. 9 B, and it shows the state that band is removed;

Figure 10 B is the skeleton view of the protrusion walls of Fig. 9 B, and it shows the state that band is installed;

Figure 11 A illustrates under the situation of the spring that is not provided for the motion of subband tensioner pivot, by the variation of the photographic fixing pressure that belt tightener produced;

Figure 11 B illustrates under the situation that is provided with the spring that is used for the motion of subband tensioner pivot, by the variation of the photographic fixing pressure that belt tightener produced;

Figure 12 A is the cut-open view according to the fixation facility of the utility model second embodiment;

Figure 12 B is the phantom view that the line XIIB-XIIB along Figure 12 A is got;

Figure 13 is the cut-open view according to the fixation facility of the utility model the 3rd embodiment;

Figure 14 A is the cut-open view according to the fixation facility of the utility model the 4th embodiment;

Figure 14 B is the phantom view that the line XIVB-XIVB along Figure 14 A is got;

Figure 15 A is the phantom view of the pressurized contact portion of belt tightener and warm-up mill in the fixation facility of Figure 14 A, and it shows sheet medium and enters state before the pressurized contact portion;

Figure 15 B is the phantom view that the line XVB-XVB along Figure 15 A is got;

Figure 16 A is the phantom view of pressurized contact portion, and it shows the state that sheet medium is discharged from from the pressurized contact portion;

Figure 16 B is the phantom view that the line XVIB-XVIB along Figure 16 A is got;

Figure 17 illustrates under the situation that is provided with the spring that is used for subband tensioner pivot motion, by the variation of the photographic fixing pressure that belt tightener produced of Figure 14 A;

Figure 18 A is the cut-open view according to the fixation facility of the utility model the 5th embodiment;

Figure 18 B is the phantom view that the line XVIIIB-XVIIIB along Figure 18 A is got; With

Figure 19 is the schematic sectional view that comprises any one imaging device in the described fixation facility.

Embodiment

Describe embodiment of the present utility model with reference to the accompanying drawings in detail.

Figure 1A shows the fixation facility according to the utility model first embodiment.By coating the elastic body 1c of thick about 0.4mm in the periphery of substrate parts 1b, and form warm-up mill 1, wherein said substrate parts 1b is the duct member of the about 25mm of external diameter and thick about 0.7mm.Warm-up mill 1 can rotate along the direction shown in the arrow Q, and comprises the column Halogen lamp LED 1a as two 1050W of thermal source in substrate parts 1b inside.By coating the elastic body 2c of thick about 0.2mm in the periphery of substrate parts 2b, and form backer roll 2, wherein said substrate parts 2b is the duct member of the about 25mm of external diameter and thick about 0.7mm.Backer roll 2 is constructed such that the pressure contact force F that is subjected between warm-up mill 1 and the backer roll 2 reaches 10kg or the following and about 10mm of roll gap length, and can rotate along the direction shown in the arrow R.

Heatproof zone 3 (being designated hereinafter simply as " band ") is the endless belt, and it is by being clamped between warm-up mill 1 and the backer roll 2 and being tensioned and removable along their periphery on backer roll 2 and belt tightener 4.What have 0.03mm or bigger thickness is with 3 to be formed by metal tube, and for example stainless-steel tube and nickel electric smelting pipe are perhaps formed by the heat stable resin pipe such as polyimide and silicone.

According to present embodiment, because the external diameter of warm-up mill 1 and backer roll 2 is configured to little diameter to 25mm, neither twine also take-up strap 3 not of warm-up mill 1 so passed through the sheet medium 5 of photographic fixing operation, this has just eliminated the needs to the parts that are used for forced apart sheet medium 5.And, by being provided, the thick PFA layer of about 30 μ m improves hardness on the superficial layer of the elastic body 1c on the warm-up mill 1.Though elastic body 1c is different with 2c thickness, they produce elastic deformation much at one, and form so-called plain-barreled roll crack (flat nip).Therefore, with 3 or the transmission speed of sheet medium 5 can not produce difference with respect to the outer circular velocity of warm-up mill 1, this makes that image can be with stable manner extremely by photographic fixing.

In the present embodiment, two thermal source 1a are placed in the warm-up mill 1, make Halogen lamp LED be disposed in diverse location optionally to be activated, temperature under easier control diverse location or the environment, promptly twine between the part of the part at warm-up mills 1 place and belt tightener 4 and warm-up mill 1 sliding contact place with 3, and the temperature between wide sheet medium and the narrow sheet medium.

Belt tightener 4 is positioned at the upstream of roll gap part in the transmission direction of sheet medium 5 of 2 of warm-up mill 1 and backer rolls, and is configured to rotate along the turning axle 2a of the direction shown in the arrow P around backer roll 2.Belt tightener 4 is constructed by this way, makes when not having sheet medium 5 to pass the roll gap part, with 3 tangentially being tensioned along warm-up mill 1.When beginning to enter the photographic fixing pressure of position of roll gap part when too big in sheet medium 5 from it, sheet medium 5 just can not enter the roll gap part smoothly, and carries out photographic fixing when may be folded at the leading end of sheet medium 5.But by being configured to can be formed into notch portion along tangentially being tensioned of warm-up mill 1 with 3, sheet medium 5 can smoothly and stably enter the roll gap part by this intake section.

Belt tightener 4 is semi-circular parts, and it is positioned at the week of heat-resistant agent, to provide tension force f to band together with backer roll 2.Therefore, be with 3 on semi-circular parts, to slide.Belt tightener 4 is positioned at such position, wherein by make with 3 and warm-up mill 1 outside the tangent line L of the pressurized contact portion between warm-up mill 1 and the backer roll 2, be subjected to press contacts, form roll gap.

Protrusion walls 4a forms by the one or both ends projection from belt tightener 4, and when being with 3 to regulate and control inclination during near protrusion walls 4a and to lopsidedness.Spring 9 at framework and protrusion walls 4a between the end face of warm-up mill 1 opposite side.Belt tightener 4 is pressed to warm-up mill 1 slightly by spring 9 thus, and be positioned such that be with 3 with warm-up mill 1 sliding contact.

For by being with 3 tensionings and drive backer roll 2 on backer roll 2 and belt tightener 4, preferably be set as greater than belt tightener 4 with the friction factor between 3 with backer roll 2 with the friction factor between 3 with stable manner.But friction factor may be invaded or the instability that becomes of wearing and tearing owing to foreign matter.On the contrary, by will being set as less than winding angle, and be set as diameter, can shorten the distance of on belt tightener 4, sliding with 3 less than backer roll 2 by diameter with belt tightener 4 with the winding angle of 3 pairs of backer rolls 2 with 3 pairs of belt tighteners 4.Therefore can avoid the labile factor that produced by time or interference variations, this makes again can be by backer roll 2 with stable manner rotating band 3.

Clearer 6 is provided at certain position between backer roll 2 and the belt tightener 4, with 3 interior perimeter surface sliding contact, remove thus with the foreign matter on 3 the interior perimeter surface, abrasion powder or the like.By removing foreign matter, abrasion powder or the like, be with 3 to be refreshed, remove labile factor thus.In addition, the recessed portion 4f that is arranged in belt tightener 4 is suitable for storing the foreign matter that is removed, abrasion powder or the like.

The roll gap inlet is defined as the position that belt tightener 4 is pressed to warm-up mill 1 place slightly, and the roll gap outlet is defined as the position that backer roll 2 is pressed towards warm-up mill 1 place.Sheet medium 5 from roll gap inlet enter and pass with 3 and warm-up mill 1 between the space so that unfixed toner image 5a by photographic fixing on sheet medium 5.Sheet medium 5 direction from the roll gap outlet along tangent line L subsequently is discharged from.

The supporting construction of backer roll 2 and belt tightener 4 will be described now.Shown in Figure 1B, the two ends of backer roll 2 turning axle 2a are supported to rotate freely (right side has been omitted among the figure) by framework 7 via bearing 7a in the left and right sides.Arm 4b is installed in the both sides of backer roll 2 turning axle 2a, freely pivoting, and forms guiding groove 4c with towards belt tightener 4 in each arm 4b.On the other hand, form leader 4d, to cooperate via spring 4e among the guiding groove 4c among the arm 4b that packs at the two ends of belt tightener 4.Therefore, belt tightener 4 has such structure, makes when it is promoted along the direction of leaving backer roll 2 by spring 4e, to being with 3 tension force f is provided.

In the present embodiment, belt tightener 4 is used as the on-rotatably moving part that slides with 3 thereon, does not need the parts of bearing and so on, and this can make supporting construction simpler.In addition, semi-circular by belt tightener 4 is formed, can by ring is lacked half towards backer roll 2, and make belt tightener 4 near backer roll 2.This also make can be formed with shorter girth be with 3.Can provide compact, cheap heating roll-type fixation facility by simplified structure thus.

And, because with 3 path movement,, can be minimized at the heat energy that when predefined paths moves, is absorbed so be with 3 for what the warm-up mill 1 that partly is received thermal source at roll gap heated along the necessary length of minimum.And, because girth is shorter, thus since atural beat to discharge the temperature drop cause less, this make can shorten from device be activated reach can carry out photographic fixing the temperature that requires required so-called preheating time.

And, because making, the tension force f that is provided with backer roll 2 by belt tightener 4 is with 3 to be subjected to press contacts to form the roll gap part with warm-up mill 1, so roll gap length can be prolonged easily and structure can be simplified, this makes facility compact also more cheap again.

For with stable manner with the unfixed toner image 5a photographic fixing that on sheet medium 5, forms, key is before unfixed toner image 5a is by photographic fixing it fully to be melted, and needs predetermined temperature and thawing time.In the present embodiment, because do not need to provide elastic body 1c that the parts that sizable distortion prolongs roll gap length take place, so that the thickness of elastic body 1c can be made is very thin by making warm-up mill 1.In addition, therefore not needing to backer roll 2 big pressurized contact pressure to be set makes elastic body be out of shape.Therefore, when the sheet medium 5 of carrying unfixed toner image 5a pass warm-up mill 1 and with 3 between the space time, only apply little stress to sheet medium 5, this is when discharging sheet medium 5 with unfixed toner image 5a photographic fixing after sheet medium 5, suppress the distortion of sheet medium, wrinkle for example occurred.

So, not only can eliminate needs, and warm-up mill 1 can be thinner to the mechanical hardness that strengthens heating roll-type fixation facility.Therefore can increase the firing rate of thermal source heating tape 3.Backer roll 2 also can be thinner, and thermal capacity can be littler, and this can reduce from the heat energy with 3 absorptions.Therefore preheating time can be shortened.

Shown in Fig. 2 and 3, the protrusion walls 4a of belt tightener 4 is positioned by carry out sliding contact with warm-up mill 1 on the 4g of sliding contact surface.Between sliding contact surface 4g and pressing surfaces 4h belt tightener 4 is provided with than with the big slit of 3 thickness (it is poor go on foot) G, wherein pressing surfaces 4h will be with 3 also thus sheet medium 5 to be pressed on the warm-up mill 1.Pressing surfaces 4h and warm-up mill 1 are with being formed centrally.More specifically, by forming slit G, and make with 3 and form thickness, just guaranteed the gap of about 30 μ m, also can carry out photographic fixing for the thick sheet medium 5 that reaches 60 μ m with stable manner even this makes with about 80 μ m with step of about 110 μ m difference.

As shown in Figure 4, be with 3 to be clamped between warm-up mill 1 and the backer roll 2, and make itself and warm-up mill be subjected to press contacts, with definition roll gap inlet by belt tightener 4.

When the inconsistency of considering various mass-produced component specifications, make as the speed in the treatment step that on sheet medium 5, forms unfixed toner image 5a of the step before the photographic fixing step, in full accord with the speed in the photographic fixing step is unpractical.Therefore, consider this inconsistency, speed in the adjacent step can be come balance by the unidirectional speed that is provided with in the photographic fixing step, promptly according to the speed in the treatment step that forms unfixed toner image 5a on the sheet medium 5, and reduces or the speed of increase in the photographic fixing step.Though need can satisfy such needs by said structure by clamping the admission velocity that sheet medium 5 limits sheet medium 5 with reliable fashion in the roll gap porch.

In addition, move with identical outer circular velocity with the surface with 3 on the surface of warm-up mill 1 elastic body 1c, with photographic fixing formed unfixed toner image 5a on sheet medium 5.But when with the leading end of 3 surface undulation injustice or sheet medium 5 when uneven, the starting condition of photographic fixing operation may become unstable.Therefore, be configured to push down warm-up mill 1 in the roll gap porch by being with 3, these two elements just can join under stable condition, and this makes that unfixed toner image 5a can be with stable manner extremely by photographic fixing.

In the present embodiment, do not have under the state that sheet medium 5 passing above, be with 3 and belt tightener 4 between form slit G.Therefore, the gap among the G of slit between warming up period just as thermofin.Just reduced thus via with 3 heats, equally just reduced thermal loss from warm-up mill 1 absorption.Therefore preheating time can be shortened.

On the other hand, when sheet medium 5 when passing the roll gap part, as shown in Figure 5, the protrusion walls 4a of belt tightener 4 is held with warm-up mill 1 and separates, this eliminated with 3 and belt tightener 4 between slit G.So, partly locate sheet medium 5 at roll gap and be with 3 to exert pressure, just be crushed on thus on the warm-up mill 1, this makes and can realize sufficient photographic fixing by using the spring 9 shown in Figure 1A that this moulding pressure is adjusted to desirable pressure.

And, the heat that is accumulated when belt tightener 4 is heated roller 1 heating is very little because slit G is arranged.Therefore, when sheet medium 5 entered the roll gap part,

sheet medium

5 and 3 coolings of being with that the first surface opposing second surface will have little thermal capacity wherein formed unfixed toner image 5a on first surface.Because seldom from the heat of belt tightener 4 sides supplies, so after the unfixed toner image 5a photographic fixing that will on the first surface of sheet medium 5, form, situation with the dual-side image photographic fixing of unfixed toner image 5a photographic fixing on second surface, earlier can be on first surface when second surface is carrying out photographic fixing by excessive heat by the image of photographic fixing, and in the image of photographic fixing on first surface, can not occur disturbing.

In the present embodiment, shown in Figure 1A, spring 9 between warm-up mill 1 and backer roll 2 the pressurized contact portion with the upstream on 3 the moving direction, in position away from the pivot center of belt tightener 4.One by driving in warm-up mill 1 and the backer roll 2 is come rotating band 3, and belt tightener 4 by this driving force and with 3 with belt tightener 4 between force of sliding friction, begin around pivot to warm-up mill 1 rotation.But, have such a case, wherein depend merely on the pivot displacing force and can't produce enough photographic fixing pressure and come photographic fixing to be formed on unfixed toner image 5a on the sheet medium 5.In order to solve this inconvenience, under the help of spring 9, the pivot displacing force is arranged to desirable photographic fixing pressure, make that unfixed toner image 5a can be with stable manner extremely by photographic fixing.

Preferably belt tightener 4 is applied to tension force f with 3 with backer roll 2, and is identical on whole tension regions.But, in some cases, backer roll 2 and belt tightener 4 collimation precision or with the precision of all homogeneity in 3 or when the wrong factor of the deflection that occurs when backer roll 2 and belt tightener 4 apply tension force, it is identical that tension force f is difficult on whole tension regions.

In addition, except that above state, as shown in Figure 6A, with 3 owing to such factor is trembleed operation, described factor for example is backer roll 2 and belt tightener 4 in its parallel accuracy of providing of place, position separately, and big more with the friction force between 3 inside surfaces and backer roll 2 and the belt tightener 4, the vibration tilting force just becomes big more, and this makes and is difficult to regulate and control run location.

Realize situation monitoring and prevent that the condition with 3 vibration from being that the situation monitoring device is set, it can respond the vibration tilting force with 3 well, and has enough loading strengths during by these situation monitoring device regulation and control with 3 position.Therefore, be with 3 whether can guarantee that loading strength is just very crucial.

Shown in Figure 1B, by belt tightener 4 is formed by spring 4e in two end supports, with at least with 3 along horizontal side edge to being with 3 tension force f is provided, and form the protrusion walls 4a that has from the edge surface of each tension force applying portion projection and control strip 3, make with 3 in protrusion walls 4a operation, be in and the tight state of contact of tension force applying portion.

For example, shown in Fig. 6 B, suppose near the side of the belt tightener 4 that is provided with protrusion walls 4a, exist to be recessed into, to go on foot difference or gap or the like.So, just can not closely contact, just formed the gap with the slidingsurface of belt tightener 4 with 3.In these cases, when being with 3 trembleing operation and during near protrusion walls 4a, bigger vibration tilting force has been applied in, fold occurs in the side edge with 3 this moment shown in Fig. 6 C.

Shown in Fig. 7 A, when considering with the oblique angle at 3 edge surface places and protrusion walls 4a with respect to the angle of strike of belt tightener 4 slidingsurfaces, under the oblique angle θ 2 with 3 edge surface places becomes situation greater than the angle of strike θ 1 of protrusion walls 4a, if be with 3 trembleing the operation and near protrusion walls 4a, then big vibration tilting force is applied in, and this moment, the side with 3 was just lifted along protrusion walls 4a as shown.On the other hand, shown in Fig. 7 B, with the oblique angle θ 2 at 3 edge surface places angle of strike θ 1 less than protrusion walls 4a, and forming between the slidingsurface of belt tightener 4 and the protrusion walls 4a under the situation in gap, if be with 3 trembleing the operation and near protrusion walls 4a, then big vibration tilting force is applied in, and this moment, the side with 3 was embedded into along the gap portion of protrusion walls 4a, produces fold in the side edge with 3 thus.

In order to prevent to produce fold in side edge with 3, shown in Fig. 8 B, need closely contact with the slidingsurface of belt tightener 4 under without any the situation in gap with 3 side area with 3, and protrusion walls 4a need have the wall surface that rises continuously from slidingsurface.Protrusion walls 4a preferably is made as the integral part of belt tightener 4.Even when protrusion walls 4a is the single parts of belt tightener 4, still preferably provide protrusion walls 4a with belt tightener 4 one, make and on the slidingsurface of belt tightener 4, slide in intimate contact, and do not stay any gap with 3.For this reason, the also preferred spring 4e that uses makes that at place, two ends support belt stretcher 4 belt tightener 4 is preferably shaped to crown when being with 3 to be tensioned shown in Figure 1B, and wherein slidingsurface is recessed into from two ends to the core.

Consider above situation, the side with 3 with when the slidingsurface of belt tightener 4 closely contact near protrusion walls 4a, the feasible effectively vibration of control strip 3, and can carrying out with 3 situation monitoring with stable manner.In the case, be with 3 to be supported by belt tightener 4 at place, two side area, the heart partly locates to have produced bending therein thus.Consider this point, shown in Fig. 8 A, closely contact under the situation of (along reference line φ) with the slidingsurface of belt tightener 4 in the side area with 3, the slidingsurface of belt tightener 4 can be shaped as crown, and wherein slidingsurface is protruding from two ends to the core.

In addition,, shown in Fig. 8 C, preferably make oblique angle θ 2 with 3 edge surface places, promptly be set as θ 2≤θ 1 less than the angle of strike θ 1 of protrusion walls 4a with respect to belt tightener 4 slidingsurfaces (reference line φ) in order to prevent fold with 3 side edge.

As make belt tightener 4 with backer roll 2 to 3 structures that apply tension force f, by forming protrusion walls 4a at backer roll 2 or belt tightener 4 sides, the vibration side with 3 trembles regulation and control thus just near protrusion walls 4a.But, under protrusion walls 4a is positioned at situation on the backer roll 2, must be subjected on the warm-up mill 1 of press contacts the structure of holding protrusion walls 4a to be set with backer roll 2.This situation may be restriction or the constraint to warm-up mill 1 design.Under the same situation that is arranged in belt tightener 4 with present embodiment of protrusion walls 4a, warm-up mill 1 can not be subjected to this design limit and be manufactured.

And, at its part place, be with 3 because tension force f is closely pasting belt tightener 4 and sliding and moving near protrusion walls 4a, realize situation monitoring thus to the vibration operation.As tension force f during, may occur crossing protrusion walls 4a or extending the phenomenon that covers a protrusion walls 4a part with 3 end face with 3 side greater than vibration operation power.Has the protrusion walls 4a that doubles at least with the band regulation and control height h of 3 thickness t in order to avoid this phenomenon increasing in, preferably shown in Fig. 9 A, to form for example with 3 limit intensity, tension force f and design freedom with 3 vibration operation power.

When closely contacting with the slidingsurface of belt tightener 4, be with 3 just to trend towards vibration with 3.Therefore, must provide such structure so that separated with backer roll 2 regulated and control by the vibration of the protrusion walls 4a of belt tightener 4 with 3.In the present embodiment, shown in Fig. 9 B, 9C, 10A and 10B, along the interior top margin formation chamfered portion 4a ' of protrusion walls 4a, guiding to the zone that forms protrusion walls 4a smoothly with 3.Shown in Fig. 9 A, band regulation and control height h is defined by not comprising chamfered portion 4a '.

Perhaps, shown in Fig. 9 D, can form chamfered portion 4a ' in the porch in the zone that forms protrusion walls 4a, so that the width of belt tightener 4 slidingsurfaces reduces gradually.

In the present embodiment, the pressurized contact portion is with the upstream on 3 the moving direction between warm-up mill 1 and backer roll 2 for spring 9, and it is away from the pivot center of belt tightener 4.Therefore, shown in Figure 11 B, because leverage, so can increase photographic fixing pressure continuously towards the pressurized contact portion between warm-up mill 1 and the backer roll 2 from the roll gap inlet, and be not applied with the stress of flex point to sheet medium 5.Therefore, in the photographic fixing image, do not produce irregular photographic fixing etc., this makes that not only unfixed toner image 5a can be with stable manner extremely by photographic fixing, and can suppress the sheet medium distortion to the sheet medium 5 of discharging after unfixed toner image 5a is by photographic fixing, wrinkle for example occur.

By way of parenthesis, the such situation of " H " expression, i.e. slab-like medium with big thermal capacity or layering sheet medium such as strip of paper used for sealing, perhaps such as the transparent sheet-like medium of OHP sheet, the situation of " S " expression standard sheet medium, and the sheet medium of " L " laminar medium of expression or poor heat resistance.

In order to compare, the moulding pressure that Figure 11 A shows under the situation that spring 9 is not set changes.In other words, in this case, only the pivotal movement by belt tightener 4 produces photographic fixing pressure, and does not have the help of spring 9.

Warm-up mill 1 and with the photographic fixing pressure (near pressure distribution) between 3 is subjected to the part place of press contacts to reach maximum pressure at warm-up mill 1 and backer roll 2 each other.Under can situation being difficult to fully melt unfixed toner image 5a with the stationary mode photographic fixing, for example when the surface undulation of sheet medium 5 not at ordinary times, perhaps should make by material on the surface with fabulous sealing, and the smooth toner image that is melted to quilt almost can't be penetrated into the inside as the OHP sheet, provide the pressure higher than the thawing stage by the final stage of passing roll gap in sheet medium 5 to the toner that melts this moment, the surface of not only being melted toner can be smooth, and can promote infiltration among the sheet medium 5, so the photographic fixing image can be more stable.

Figure 12 A and 12B show the fixation facility according to the utility model second embodiment.With among first embodiment similarly parts represent with identical label, and will omit repetition of explanation to it.

In first embodiment, allow belt tightener 4 around the axle rotation predetermined angular common with the turning axle 2a of backer roll 2.In the present embodiment, belt tightener 4 is configured to be allowed to rotate predetermined angular around axle 7b, and its axis 7b is different from the turning axle 2a of backer roll 2.

In other words, arm 4b is installed in a 7b both sides, and wherein said axle 7b is set at the position in the axle center that is different from turning axle 2a, and forms guiding groove 4c with towards belt tightener 4 in each arm 4b.On the other hand, form leader 4d, to cooperate among the guiding groove 4c of the arm 4b that packs into via spring 4e at the two ends of belt tightener 4.Therefore belt tightener 4 has such structure, makes when it is promoted along the direction of leaving backer roll 2 by spring 4e, to being with 3 tension force f is provided.

This structure can change the torque (increasing torque in the present embodiment) that acts on the belt tightener 4, and this makes and can come the pressure contact force that is subjected between accommodation zone 3 and the warm-up mill 1 according to the position of axle 7b.And in the present embodiment, as shown in Figure 2, between sliding contact surface 4g and pressing surfaces 4h, belt tightener 4 is provided with than with the big slit of 3 thickness (it is poor go on foot) G, wherein pressing surfaces 4h will be with 3 also thus sheet medium 5 to be pressed on the warm-up mill 1.

Figure 13 shows the fixation facility according to the utility model the 3rd embodiment.With among first embodiment similarly parts represent with identical label, and will omit repetition of explanation to it.

In the present embodiment, belt tightener 4 is arranged to non-rotatable cylindrical member.And in the present embodiment, as shown in Figure 2, between sliding contact surface 4g and pressing surfaces 4h, belt tightener 4 is provided with than with the big slit of 3 thickness (it is poor go on foot) G, wherein pressing surfaces 4h will be with 3 also thus sheet medium 5 to be pressed on the warm-up mill 1.

To the 4th embodiment of the present utility model be described with reference to figure 14A to 17.With among first embodiment similarly parts represent with identical label, and will omit repetition of explanation to it.

In the present embodiment, belt tightener 4 is positioned at the downstream of pressurized contact portion in the transmission direction of sheet medium 5 of 2 of warm-up mill 1 and backer rolls, and is allowed to rotate along the turning axle 2a of the direction shown in the arrow P around backer roll 2, shown in Figure 14 A and 14B.

Belt tightener 4 is semi-circular parts, and it is positioned at the week of heat-resistant agent, to provide tension force f to band together with backer roll 2.Therefore, be with 3 on semi-circular parts, to slide.

The inlet of fusing nip is defined as the position that belt tightener 4 is pressed to warm-up mill 1 place slightly, and the outlet of fusing nip is defined as the position that belt tightener 4 and warm-up mill 1 separate the place.Sheet medium 5 from roll gap inlet enter and pass with 3 and warm-up mill 1 between the space so that unfixed toner image 5a by photographic fixing on sheet medium 5.Sheet medium 5 direction from the roll gap outlet along tangent line L subsequently is discharged from.

Shown in Figure 15 A and 15B, the protrusion walls 4a of belt tightener 4 is positioned by carry out sliding contact with warm-up mill 1 on the 4g of sliding contact surface.Between sliding contact surface 4g and pressing surfaces 4h belt tightener 4 is provided with than with the big slit of 3 thickness (it is poor go on foot) G, pressing surfaces 4h will be with 3 also thus sheet medium 5 to be pressed on the warm-up mill 1.Pressing surfaces 4h and warm-up mill 1 are with being formed centrally.More specifically, by forming slit G, and make with 3 and form thickness, just guaranteed the gap of about 30 μ m, also can carry out photographic fixing for the thick sheet medium 5 that reaches 60 μ m with stable manner even this makes with about 80 μ m with step of about 110 μ m difference.

Be with 3 to be clamped between warm-up mill 1 and the backer roll 2, and make itself and warm-up mill 1 be subjected to press contacts in the exit of roll-gap region by belt tightener 4.

On the other hand, when sheet medium 5 when passing fusing nip portion, shown in Figure 16 A and 16B, the protrusion walls 4a of belt tightener 4 is held with warm-up mill 1 and separates, this eliminated with 3 and belt tightener 4 between slit G.Thus, be with 3 to exert pressure in fusing nip portion place sheet medium 5, and therefore be crushed on the warm-up mill 1, this makes and can realize sufficient photographic fixing by using the spring 9 shown in Figure 14 A that this moulding pressure is adjusted to desirable pressure.

And, the heat that is accumulated when belt tightener 4 is heated roller 1 heating is very little owing to the existence that slit G is arranged.Therefore, when sheet medium 5 entered the roll gap part,

sheet medium

When driving warm-up mill 1 or backer roll 2, be with 3 to be driven, and belt tightener 4 by this driving force and with 3 with belt tightener 4 between force of sliding friction, begin on the direction of leaving warm-up mill 1, to pivot.But, by desirable photographic fixing pressure being set, can come photographic fixing unfixed toner image 5a with stable manner extremely by pushing belt tightener 4 to warm-up mill 1 greater than the desirable thrust of pivot displacing force.

Therefore, in the present embodiment, the pressurized contact portion is with the downstream on 3 the moving direction between warm-up mill 1 and backer roll 2 for spring 9, and it is away from the pivot center of belt tightener 4.

In the present embodiment, the pressurized contact portion is with the downstream on 3 the moving direction between warm-up mill 1 and backer roll 2 for spring 9, and it is away from the pivot center of belt tightener 4.Therefore, as shown in figure 17, because leverage can increase photographic fixing pressure continuously towards the pressurized contact portion between warm-up mill 1 and the backer roll 2 from the roll gap inlet, and can not be applied with the stress of flex point to sheet medium 5.Therefore, in the photographic fixing image, do not produce irregular photographic fixing etc., this makes that not only unfixed toner image 5a can be with stable manner extremely by photographic fixing, and can suppress the sheet medium distortion to the sheet medium 5 of discharging after unfixed toner image 5a is by photographic fixing, wrinkle for example occur.

Figure 18 A and 18B show the fixation facility according to the utility model the 5th embodiment.With among the 4th embodiment similarly parts represent with identical label, and will omit repetition of explanation to it.

In the 4th embodiment, allow belt tightener 4 around the axle rotation predetermined angular common with the turning axle 2a of backer roll 2.In the present embodiment, belt tightener 4 is configured to be allowed to rotate predetermined angular around axle 7b, and its axis 7b is different from the turning axle 2a of backer roll 2.

In other words, arm 4b is installed in a 7b both sides, and freely pivoting, wherein said axle 7b is set at the position in the axle center that is different from turning axle 2a, and forms guiding groove 4c with towards belt tightener 4 in each arm 4b.On the other hand, form leader 4d, to cooperate among the guiding groove 4c of the arm 4b that packs into via spring 4e at the two ends of belt tightener 4.Therefore belt tightener 4 has such structure, makes when it is promoted along the direction of leaving backer roll 2 by spring 4e, to being with 3 tension force f is provided.

This structure can change the torque (increasing torque in the present embodiment) that acts on the belt tightener 4, and this makes and can come the pressure contact force that is subjected between accommodation zone 3 and the warm-up mill 1 according to the position of axle 7b.

In above embodiment, warm-up mill 1 or backer roll 2 are as driven roller.In the case, in order to realize safe driving, preferably use any harder roller as driven roller, and the roller that another is softer is as driven voller.Make and be with 3 to twine backer rolls 2 and changeed by ring, and be coated in warm-up mill 1 lip-deep elastic body 1c and be subjected to press contacts.In the case, because backer roll 2 is as driven roller, and warm-up mill 1 so backer roll 2 is determined the transmission speed with 3, promptly carries the speed of the sheet medium 5 of unfixed toner image 5a as driven voller.Backer roll 2 is configured to have harder than elastic body 1c at least surface.This structure can realize having the driving of stable transfer speed, and can not cause distortion.

In above embodiment, can control the rotating speed of warm-up mill 1 and backer roll 2 selectively.Control to actuating speed will be described now.Driver part has two rotating speeds that drive warm-up mill 1 and backer roll 2, and optionally drives warm-up mill 1 and backer roll 2 with first rotating speed or second rotating speed slower than first rotating speed according to sheet medium character.

For rotating speed is set, the detecting device that detects the sheet medium character is provided, also provide to be used for table of selecting corresponding to sheet medium character rotating speed or the like.When the sheet medium 5 of carrying unfixed toner image 5a detects the character of sheet medium when being transmitted, when handling the photographic fixing order, according to the sheet medium character that is detected by showing to select rotating speed.

In order to select rotating speed, can be before handling the photographic fixing order parts of manual operation and fixation facility interlocking, perhaps come Long-distance Control by electric signal or the like.

Use the sheet medium 5 of carrying unfixed toner image 5a probably with various purposes, comprise slab-like medium typical scraps of paper medium and so on, that have big thermal capacity, transparent sheet-like medium (OHP sheet) or the like.Compare with typical sheet medium, for the slab-like medium such as strip of paper used for sealing and layering sheet medium, transparent sheet-like medium (OHP sheet medium) or the like with big thermal capacity, before unfixed toner image 5a is by photographic fixing thereon, need the long relatively time period that toner image 5a is fully melted.In this case, by optionally driving warm-up mill 1 and backer roll 2 with first rotating speed or second rotating speed slower than first rotating speed according to sheet medium character, unfixed toner image 5a is fully melted, and can realize desirable photographic fixing.

In addition, even by optionally driving with first rotating speed or second rotating speed, when the sheet medium 5 of carrying unfixed toner image 5a pass warm-up mill 1 and with 3 between the space time, be applied to stress on this sheet medium 5 and also change hardly and keep very little.This has suppressed the distortion of sheet medium when unfixed toner image 5a photographic fixing is discharged sheet medium 5 after sheet medium 5, wrinkle for example occur.Therefore, not only can eliminate needs, and warm-up mill 1 can be thinner to the mechanical hardness that strengthens heating roll-type fixation facility.Therefore can increase the firing rate of thermal source heating tape 3.In addition, because backer roll 2 also can be thinner, thermal capacity can be littler.So just reduced from 3 heat energy that absorb, this can shorten to be activated from device and reaches the required so-called preheating time of predetermined temperature that can carry out photographic fixing.Optionally drive and to realize by the rotating speed that for example optionally changes drive motor.

Figure 19 shows any imaging device 10 that comprises in the aforesaid fixation facility.

Imaging device 10 comprises housing 10a, discharges pallet 10c and be installed in the door closure 10b that housing 10a is anterior and can freely open and close at the medium of housing 10a top formation.In housing 10a inside exposing unit W, image-generating unit D are set, have the conveyor unit 29 and the media feeding unit 30 of image transmitter 18.Medium transmission unit 11 is set near door 10b.Each unit all removably is loaded into housing 10a inside, makes during maintenance work or the like in order to keep in repair or to change, and in the unit any one can be pulled down from housing 10a separately.

Image-generating unit D comprises a plurality of (being four in this embodiment) imaging station Y (yellow), M (magenta), C (cyan) and K (black), each all forms the image of different colours.Among imaging station Y, M, C and the K each all comprises: the image vehicle 17 that comprises photosensitive drums; And the charger 19 and the developing apparatus 20 that comprise crown charger, the two all is positioned at the periphery of image vehicle 17.Each imaging station Y, M, C and K are arranged in parallel along arcuate line under conveyor unit 29, and image vehicle 17 is up.The order of placement of each imaging station Y, M, C and K is arbitrarily.

Conveyor unit 29 comprises: driven roller 12, and the diagram drive source that is positioned at housing 10a lower end drives and rotates; Driven voller 13 is positioned at above the diagonal angle of driven roller 12; Idler roller 14; The image transmitter 18 that comprises the intermediate transport band, described intermediate transport band be in these three rollers or wherein tensioning at least two, and be driven to change along the directional ring shown in the arrow S; With the lip-deep clearer 15 that abuts against image transmitter 18.Driven voller 13, idler roller 14 and image transmitter 18 are arranged such that the ring of image transmitter 18 changes the path and tilts to extend.More specifically, it is lower that they are arranged such that in the band transmission direction down belt surface 18a is positioned, and up belt surface 18b is positioned higher in the band transmission direction.

Like this, imaging station Y, M, C and K are tilted layout.The belt surface 18a of image transmitter 18 contacts with image vehicle 17 along arcuate line, and image vehicle 17 is actuated to rotate in the transmission direction of as shown by arrows image transmitter 18 subsequently.The flexible image transmitter 18 of annular cover shape contacts with image vehicle 17 with winding angle much at one, with from last overlay image vehicle 17.This structure can be applied to arrangement interval, winding angle (arc curvature) of tension force, the image vehicle 17 of image transmitter 18 or the like by control from idler roller 14, regulate pressurized contact pressure or roll-gap width between image vehicle 17 and the image transmitter 18.

Driven roller 12 also is used as the spare roll of secondary transfer roller 39.Form rubber layer on the outer surface of driven roller 12, it has for example thickness and 10 of about 3mm ⁵Ω cm or specific insulation still less, and will be via the ground connection of the metal shaft conductive path as the secondary bias voltage that provides via secondary transfer roller 39.Like this, by the rubber layer with high friction and impact absorption ability is provided to driven roller 12, the impact when sheet medium enters secondary translator unit just is delivered to image transmitter 18 hardly, and this can prevent the picture quality variation.In addition, the diameter by making driven roller 12 has passed through the sheet medium of secondary transmission and can have been separated more easily by the elastic force of himself less than the diameter of driven voller 13 and spare roll 14.In addition, driven voller 13 also is used as the spare roll of following described clearer 15.

Perhaps, the vergence direction that image transmitter 18 rings change the path is arbitrarily, and correspondingly is specified to the arrangement of picture station Y, M, C and K.

Clearer 15 is located at down this side of belt surface 18a in the band transmission direction, and being provided with cleaning blade 15a and the toner transmitter 15b that transmits the toner that is collected, cleaning blade 15a removes and stay image transmitter 18 lip-deep toners after secondary transmission.Cleaning blade 15a abuts against on the image transmitter 18 in the wound portion office of 18 pairs of driven vollers 13 of image transmitter.The one-level transfer member 16 relative with the image vehicle 17 of each imaging described below station Y, M, C and K abuts against on the rear side of image transmitter 18, will transmit bias voltage thus and be applied on the one-level translator unit 16.

Exposing unit W is arranged in the space under the image-generating unit D that is in tilted layout.And media feeding unit 30 is positioned at the place, bottom of housing 10a under the exposing unit W.Exposing unit W is contained in the casing by whole, and described casing is located in the band transmission direction in the formed space, diagonal angle below of belt surface 18a down.Be horizontally disposed with the single scanner 21 that comprises polygon mirror motor 21a, polygon mirror (polygonal rotating mirror) 21b at bottom half.Single f-θ lens 22 and a plurality of catoptron 24 are set in optical system B, they are also not parallel each other and the scanning light path of each color turned back to corresponding image vehicle 17, wherein, described optical system B reflects on polygon mirror 21b from a plurality of by its laser beam of the picture signal of the color LASER Light Source 23 of modulating separately, and described laser beam is deflected and is scanned on each image vehicle 17.

In the exposing unit W that as above constructs, from polygon mirror 21b with the shades of colour image signals corresponding, be launched with the laser beam form that forms and modulate according to the common data clock frequency, and be irradiated on the image vehicle 17 among each imaging station Y, M, C and the K by f-θ lens 22 and catoptron 24, to form sub-image.Make scan light bend folding by cremasteric reflex mirror 24, can reduce the height of casing thus, this can realize compact optical system again.

And catoptron 24 is configured such that the length of the scanning light path on the image vehicle 17 among each imaging station Y, M, C and the K all equates.By being configured to like this, promptly the optical path length (light path) from polygon mirror 21b to each image vehicle 17 becomes almost equal with respect to image-generating unit D among the exposing unit W, and the sweep length of the light beam that is scanned via each light path also becomes almost equal.This has just eliminated the needs for the special tectonic that forms picture signal.Therefore, LASER Light Source is used to the different images signal modulation of the image of different colours; But, it can come modulated according to the corporate data clock frequency, and because of using common reflecting surface, so can prevent the different relatively gamuts that cause by sub scanning direction.Can make cheap color image forming apparatus thus with simple structure.

In addition, in this device, by scanning optics being arranged on the downside of device, can make by the drive system from device and be imposed on the vibration of framework of support imaging device and the vibration minimum of the scanning optics that causes, this can prevent the picture quality variation again.Particularly, by scanner 21 is arranged on bottom half, can makes the vibration minimum of the whole housing 10a that is caused by polygon mirror motor 21a, and can prevent the picture quality variation.And by being one as the restricted number of the polygon motor 21a of vibration source, the vibration that is applied to whole housing can be minimum.

Media feeding unit 30 is provided with boxlike pallet 35 and extracts roller 36, and a lamination shape medium is housed in the tray salver 35, extracts roller 36 and presents sheet medium from boxlike pallet 35 one by one.Medium transmission unit 11 be provided with the regulation and control sheet medium to secondary translator unit present regularly an opposite house roller 37 (one of them is positioned at housing 10a side), and driven roller 12 and image transmitter 18 be subjected to secondary transfer roller 39, main transmission path 38, fixation unit 40, a pair of distributing roller 41 and the duplex printing transmission path 42 of press contacts.

By the secondary unfixed toner image that is sent to sheet medium, under predetermined temperature, partly locating by photographic fixing by fixation unit 40 formed roll gaps.In the present embodiment, fixation unit 40 can be arranged in the diagonal angle superjacent air space of the belt surface 18b that is formed at travelling belt, up, in other words, described space is promptly with respect to the space of travelling belt in imaging station Y, the relative side with K of M, C in transmission direction for belt surface 18b.This structure can reduce the heat that is passed to exposing unit W, image transmitter 18 and imaging device, and can reduce the frequency to versicolor gamut correct operation.Particularly, exposing unit W is from fixation unit 40 position farthest, and can make by the distortion minimum in the caused scanning optics element of heat, and this has prevented gamut again.

In the present embodiment, because image transmitter 18 extends along the diagonal angle, so can guarantee that on the right side of accompanying drawing very wide space is provided with fixation unit 40.Therefore, not only this device can be made compact, and can prevent that the heat that produces in fixation unit 40 is delivered to exposing unit W, image transmitter 18 and each imaging station Y, M, C and K, and these all are arranged in the left side of accompanying drawing.And, because exposing unit W can be arranged in the space of image-generating unit D lower-left, so can make the vibration minimum that is imposed on scanning optics among the caused exposing unit W of vibration of housing 10a by the drive system from image-generating unit D, this can prevent the picture quality variation again.

Because clearer is not set, so crown charger 19 is used as charger.Comprise at charger under the situation of roller that the one-level on image vehicle 17 transmits the residue toner and is accumulated on the roller, though be micro-, but still cause charge fault.But it is on the crown charger 19 of non-contact charge device that toner is attached to hardly.Therefore can prevent charge fault.

In this device, the intermediate transport band is used as image transmitter 18 and is configured to contact with image vehicle 17.But, image transmitter 18 can be the sheet medium transport tape, and it is inhaled sheet medium from the teeth outwards, and in toner image sequentially being transmitted with the lip-deep process that overlaps sheet medium, move and transmit sheet medium, and be configured to contact with image vehicle 17.In the case, make band transmission direction as the sheet medium transport tape of image transmitter 18, with lower surface that image vehicle 17 contacts on up.

Should be realized that the utility model is not limited to above embodiment, and can improve in every way.For example, although more than described the tandem type color image forming apparatus that wherein versicolor developing apparatus is arranged, but the utility model can be applied to rotary color image forming apparatus, wherein versicolor developing apparatus is installed on the rotating frame, and the utility model also can be applied to the forming monochrome image device.

Claims

1. fixation facility is used for the unfixed toner image photographic fixing that will be formed on the sheet-shaped recording medium, it is characterized in that described fixation facility comprises:

First roller wherein comprises thermal source;

Second roller is pressed towards described first roller;

Make described first transverse curvature of described belt tightener along described endless belt.

2. fixation facility as claimed in claim 1 is characterized in that, wherein makes described first the transverse center part of described belt tightener partly recessed from its described two lateral end.

3. fixation facility as claimed in claim 1 is characterized in that, described first the transverse center part of described belt tightener is partly protruded from its described two lateral end.

4. fixation facility as claimed in claim 1, it is characterized in that, wherein said endless belt of being changeed by ring is clamped between described first roller and the described belt tightener to form the second roll gap part, described unfixed toner image is passed the described second roll gap part, under from the effect of the heat of described thermal source by photographic fixing on described recording medium.

5. fixation facility as claimed in claim 4, it is characterized in that, wherein in order to limit the vibration campaign of described endless belt of being changeed by ring, described belt tightener comprises wall components, and described wall components has and described two lateral end of described endless belt at least one adjacent second in partly.

6. fixation facility as claimed in claim 5 is characterized in that, wherein said wall components and described belt tightener are integrally formed.

7. fixation facility as claimed in claim 6 is characterized in that, wherein said wall components and described belt tightener are whole to be formed.

8. fixation facility as claimed in claim 6 is characterized in that, wherein makes described second described first extension continuously from described belt tightener of described wall components.

9. fixation facility as claimed in claim 8 is characterized in that, wherein:

Described second of described wall components forms first angle with in the described lateral end part of described endless belt one of described belt tightener described first; And

Described first of the side end face of described endless belt and described belt tightener in the described lateral end part of described endless belt one forms second angle, and described second angle is less than described first angle.

10. fixation facility as claimed in claim 5 is characterized in that the height dimension of wherein said wall components is greater than the gauge of described endless belt.

11. fixation facility as claimed in claim 5 is characterized in that, wherein said wall components is formed with scarf, and described scarf extends to described second, described endless belt of being changeed by ring is directed among described first of described belt tightener.

12. fixation facility as claimed in claim 5 is characterized in that, the part of wherein said wall components abuts against on described first roller, partly to locate to limit the slit between described first roller and described belt tightener described first at described second roll gap.

13. fixation facility as claimed in claim 12 is characterized in that, wherein:

State distance between first roller and described belt tightener described first in place, described slit greater than the gauge of described endless belt; And

Determine described distance, make when described recording medium enters the described second roll gap part that described first of described belt tightener is pressed in described recording medium on described first roller by described endless belt.

14. fixation facility as claimed in claim 1 is characterized in that, wherein said belt tightener can pivot.

15. fixation facility as claimed in claim 14 is characterized in that, also comprises the elastomeric element of described belt tightener being pushed to described first roller.

16. fixation facility as claimed in claim 14 is characterized in that, the pivot center of wherein said belt tightener is identical with the turning axle of described second roller.

17. fixation facility as claimed in claim 14 is characterized in that, the pivot center of wherein said belt tightener is different from the turning axle of described second roller.

18. fixation facility as claimed in claim 1 is characterized in that, wherein said belt tightener has to be seen from the described horizontal direction of described endless belt and to be semiorbicular xsect.

19. fixation facility as claimed in claim 18 is characterized in that, also comprises clearer, described clearer is between described second roller and described belt tightener, on the inner peripheral surface that abuts against described endless belt.

20. fixation facility as claimed in claim 1 is characterized in that, wherein said belt tightener has from the described horizontal direction of described endless belt sees ringwise xsect.

21. fixation facility as claimed in claim 1 is characterized in that, wherein said belt tightener is positioned at the upstream side of the described ring veer of described endless belt with respect to the described first roll gap part.

22. fixation facility as claimed in claim 1 is characterized in that, wherein said belt tightener is positioned at the downstream of the described ring veer of described endless belt with respect to the described first roll gap part.

23. an imaging device is characterized in that, comprising:

Imaging device, it forms toner image on recording medium; With

Fixation facility as claimed in claim 1, it is used for the described toner image on the described recording medium.