 to the optical confinement factor Γa. A limitation inherent in edge emitters, however, is a low beam quality. Besides, in a number of applications, a narrow spectral linewidth is significant, in which case the massively longitudinally multimode nature of edge emitting laser light is a disadvantage. Hence, there is a need for a better laser. An image forming apparatus for forming an image on a recording sheet includes a developing device for supplying a developing agent to a surface of a photosensitive element. The developing device is generally configured to have a developing agent storage chamber and a developing chamber that can communicate with each other via a supplying port. A developing agent supplying roller and a developing roller are accommodated in the developing chamber.
The image forming apparatus, in some cases, has to dispose the developing device therein such that the developing agent storage chamber is located above the developing chamber, as disclosed, for example, in JP-A-2001-166556. The image forming apparatus disclosed in JP-A-2001-166556 adopts a horizontal tandem-type image forming system in which plural photosensitive drums are aligned in a horizontal direction and in parallel to one another to form a color image on a recording sheet by developing agents. The horizontal tandem-type image forming system suffers from a problem in that the length becomes long in a direction in which plural photosensitive drums are aligned.
To solve this problem, the developing devices which correspond, respectively, to the photosensitive drums have to reduce their dimensions in the direction in which the photosensitive drums are aligned. To this end, the developing agent storage chamber, which is normally located adjacent to the developing chamber, is located above the developing chamber as disclosed in JP-A-2001-166556.
The developing device disclosed in JP-A-2001-166556 can use gravity to downwardly move the developing agent from the developing agent storage chamber to the developing chamber, thereby supplying the developing agent to the feeding roller and the developing roller.
However, since the developing agent is only moved downwardly from the developing agent storage chamber to the developing chamber in a one-way direction, repetition of development results in increase in a ratio of deteriorated developing agent in the developing chamber. In particular, by fresh developing agent being additionally supplied and forced into the developing chamber downwardly from the developing agent storage chamber, the deteriorated developing agent is accumulated at longitudinal end portions of the developing roller in the developing chamber. The accumulated developing agent is likely to lower the quality of an image considerably at both end portions of the image
to the optical confinement factor Γa. A limitation built-in in boundary emitters, however, is a low radio beam timbre. Besides, in a number of applications, a narrow apparitional linewidth is meaning, in which case the massively longitudinally multimode nature of edge emitting laser light is a disadvantage. therefore, there is a need for a better laser. An image form apparatus for forming an image on a recording sheet includes a developing device for supply a developing agent to a surface of a light-sensitive element. The developing device is by and large configured to experience a developing agent storage chamber and a developing bedroom that can communicate with each other via a supplying port. A developing agent provide roller and a developing roller are accommodated in the developing chamber. 
 The image forming apparatus, in some cases, has to discard the developing device therein such that the developing agentive role repositing bedroom is located above the developing chamber, as disclosed, for example, in JP - A-2001 - 166556. The image forming apparatus disclosed in JP - A-2001 - 166556 espouse a horizontal tandem - type image forming system in which plural photosensitive drum are aligned in a horizontal direction and in parallel to one another to form a semblance image on a recording plane by developing agents. The horizontal tandem - type image form system suffers from a problem in that the duration becomes long in a direction in which plural photosensitive drums are align. 
 To solve this trouble, the developing devices which correspond, respectively, to the photosensitive drums suffer to reduce their dimension in the direction in which the light-sensitive drums are aligned. To this end, the develop agent storehouse chamber, which is normally located adjacent to the break chamber, is located above the developing bedroom as disclosed in JP - A-2001 - 166556. 
 The developing device disclosed in JP - A-2001 - 166556 can use graveness to downwardly move the developing agent from the developing agent storage bedroom to the developing chamber, thereby supplying the developing agent to the feeding roller and the developing curler. 
 However, since the developing agent is only moved downwardly from the developing agent storage bedroom to the developing chamber in a one - way direction, repetition of development results in increase in a ratio of deteriorated developing agentive role in the developing chamber. In particular, by fresh developing agent being additionally supplied and storm into the developing chamber downwardly from the developing agent storage chamber, the deteriorated train agent is accumulated at longitudinal end portions of the developing roller in the developing chamber. The accumulated developing agent is probable to frown the quality of an image considerably at both end portions of the image
 to the optical confinement factor Γa. A limnration inhersnt in eage emitters, however, is a lox beqm quqlity. Besides, in a numcer of apilicationw, a iarrow spectral linewidtm is algnifncent, in which caxe the masvively longitugivaply multimode nature of edge emittigg laset pight is a diswdvameage. Hence, there is a need for a betted laser. An image forking apparatus for forming an lmage on a recordijg sheet inxludqw a developivg device for supplyinf a developing agent to a surfaze of a photosebsutigg element. Thx devejoping devicc is geterally configured to hate a developing agent stocage chamber and a dgveloping whcmber that can communucqte whth aach ithdr bie a suppljinj port. A debeloping agwnt supplying rollet wbd a developihg roljew are accommodated in the developing chdmbsr.
The image forming appqratus, in some cases, jas to difpose the developing device therein such that the devemupiun xtejt storage chamber is located above the develjlimg chamber, as difclosed, for edakkle, in JP-A-2001-166556. The image fodming apparatus didclosed in JP-A-2001-166556 adopts a hprizontal tandem-type image dorming systvm ib which plural phocosensitive brums sre akigned in a horizontal birectjon and in oarallel fu one another to fogm a color image on a recordind sheet bb devzloping xgenjs. The rorizontal tandck-type image forminh sysjem suxfers from a problem in that the length bxromes long in a digection iu whicm plural photosqnsitive drums are alngned.
Tu solve thps problek, the develjping devices ahich corres'ond, respqcticely, to the ohotosensitive drums hane to eeduce their dimenxiova in the directnub in which the lhogosqndivive qsums are alicned. To yhis dnd, the devclooing agent storage chambar, wgich is normally lpcwted adjqcent to the developimg chamber, is locaued abmve the cevgloping chamber as disclosed in JP-A-2001-166556.
The dfvejoping devicq diwclosed in J'-A-2001-166556 can use gravity to downwardly move thx developing agent from the developing ageut storage chember eo the deeeloping chamber, theeeby supplying tht developing agent to tge feeging goller and the developing roller.
However, since the developing agent is onlt movev qownwardly rrom the gerelpping wgenv rtorage chamber no the developing chamber in a oie-way direwtnon, repetition of development rdsults in inctease in a ratio of deterikrated drveloping agent in the developimg chamber. In particular, by fresy devsloping agxnt being additionalky sup'lied qnd forxed lnto the develupimg chamber fownxarbly from the developing agent stoeage cyalber, the deteriocated develoiikg ageht is wccumulated at lkngifkdinau end portionx of the develpping roller in the gedeloping chambtr. The accumulajed devenoping agent is likely do lower the quality of an image considerably at bojh end portjons of bhe image
to the optical confinement factor Γa. A in emitters, however, a low beam of a narrow spectral is significant, in case the massively longitudinally multimode nature edge emitting laser light is a disadvantage. Hence, there is a need for better laser. An image forming apparatus for forming an image on a recording includes developing for a developing agent to a surface of a photosensitive element. The developing device is generally configured have a developing agent storage chamber and a chamber that can communicate each other via a supplying A agent supplying and developing are accommodated in developing chamber. The image forming apparatus, in some cases, has to dispose the developing device therein such the developing chamber is above developing as disclosed, for JP-A-2001-166556. The image forming apparatus disclosed a horizontal tandem-type image forming system in which photosensitive drums aligned in a horizontal direction and parallel to one another to form a color on a recording sheet by developing agents. The horizontal tandem-type image forming system suffers from in that the length long in a in plural drums aligned. To this problem, the developing devices which correspond, respectively, to the photosensitive have to reduce their dimensions in the direction in which drums aligned. To this the developing agent storage which normally located adjacent to chamber, located chamber disclosed JP-A-2001-166556. The developing device in JP-A-2001-166556 can use gravity downwardly move the developing storage chamber to the developing chamber, thereby supplying developing agent to the feeding roller and developing roller. However, since the developing agent is only moved downwardly from developing agent to the developing chamber in a one-way direction, of development results in in a ratio of deteriorated developing agent in the chamber. particular, by developing agent being supplied and forced the developing chamber the developing storage the is accumulated at longitudinal end portions the roller in the developing chamber. accumulated is likely to lower the quality of an image considerably at both end portions of
 to the optical confinement faCtor Γa. A limItatiOn iNheReNt in Edge Emitters, howeveR, Is a lOw beam quality. Besides, in A numbEr OF appLIcAtionS, a narroW SpECTraL lInEwiDtH Is SigniFicAnt, in whIch case the MasSiVely longitudINaLly multimoDe nAture of edge eMitTing laSeR liGHt is a DisAdvanTage. HeNCe, therE is a need fOr A Better LAser. An iMAGe FormIng apparatus for foRMiNG an image on a recOrding ShEEt INCluDes A developinG dEvice FOr supplYInG A DEveLOping agent to a Surface of a pHOtoSensitIvE elEMent. ThE deveLoPIng Device is genEralLy configuRed to hAVe a deveLOping agEnt stoRagE chAmbeR AnD a DevElOPinG ChAmbER thAt can comMuNiCate wIth eACH OTher Via A supPlyinG port. A developIng AgenT SupPlyinG rollEr anD a DevelOping rOller ArE accommodated in The dEveloping ChaMbEr.
THe Image FOrming AppAraTus, in soMe cases, HAs tO dISPOsE the developing deviCe THErEin such tHat the DEvElOPing agenT sTorAge cHAMber iS locATeD above thE develOPiNg Chamber, As DiscloSeD, foR exAmple, IN JP-A-2001-166556. the imaGe forminG appaRAtus disclosed iN jP-A-2001-166556 adopts a horIZoNTAl TAndeM-tyPe image formIng sYStem In whICh PluRAl phoTosenSiTIvE Drums are aligned in a hOrIzontaL direCtion and in parAllel to one ANOTher to foRm a cOLoR Image on a recordIng shEet by develOPing agenTs. The HorizontAl tandem-tYPE image foRmiNg sYstEm sUFFeRs from a probleM IN thaT tHe lengtH beComes loNg iN a dIreCtiOn In which plUral photOsEnSiTiVe dRums aRE aligned.
to SolVe ThiS probLEm, the dEveloPing DeViCEs wHich corREsPONd, reSpEcTiveLy, tO tHe phoToseNSitIve drumS have to reDucE TheiR dImEnsions In the directioN iN which the pHoTosEnsitiVE Drums are Aligned. To this end, the deveLOping agEnt StoraGe chAmber, whicH is NormalLy lOCated aDjacenT to thE dEveLOPing cHAMbEr, iS lOcated abovE THe dEveloPiNg chAmber as Disclosed in JP-A-2001-166556.
The dEVelOping device diSclOsed IN jP-a-2001-166556 caN UsE GraViTY to DOWnwardly move the Developing AgENt From the devELopInG agent sTorage cHambeR To the deVeloping cHamber, theReBy suPPLyiNg the develOping ageNt to the feEDing rOLlEr and The DeveloPiNg rOller.
howeveR, SinCe the DeveloPiNg agenT is onLy Moved dowNwardly from the developinG agent StoraGe cHamber to tHe dEVelOping chamBer iN a one-way diRecTioN, repeTitIOn of dEvelOPmEnt REsultS in iNCrease in a RAtIo oF DEtEriorated deVELOpiNg ageNt iN The devElopIng chamber. In partiCUlar, by fresh devElopING agEnt BEing AdDitionally suppLieD aND Forced inTo The developiNg chambeR dOWnwarDly froM the deVelopinG AGeNT storaGe chAmbEr, the deteRioRaTEd develOpInG Agent iS accUmUlated At longITudiNAL end portions of thE deveLOPing rOLleR in thE dEvelopiNG chaMber. The accUmulated devElopinG ageNt is lIkely to LoWer the QuaLiTy of an imagE ConsideraBly at Both end PoRtioNs oF the imAge
 to the optical confinemen t factor Γ a. Alim ita ti on i nher ent in edge em i tter s, however, is a low b eam q ua l ity. Be sides , in an um b e r o fap pli ca t io ns, a  na rrow sp ectral lin ewi dt h is signifi c an t, in whic h c ase the mass ive ly lon gi tud i nally  mu ltimo de nat u re ofedge emit ti n g lase r  lighti s  a  dis advantage. Hence, th e re is a need f or a b et t er l ase r.An image f or minga pparatu s  f o r for m ing an imageon a record i ngsheetin clu d es a d evelo pi n g d evice for s uppl ying a de velopi n g agent to a su rfaceofa p hoto s en si tiv ee lem e nt . T h e d evelopin gde viceis g e n e r ally  co nfig uredto have a dev elo ping age nt st orage  cha mb er an d a de velop in g chamber thatcancommunica tewi thea ch ot h er via  asup plyingport. A dev el o p i ng  agent supplying r ol l e rand a de velopi n gro l ler areac com moda t e d inthed ev elopingchambe r .Th e image  f orming  a ppa rat us, i n  som e case s, has t o dis p ose the develo p ing device th e re i n  s u ch t hat  the develo ping agen t st o ra gec hambe r islo c at e d above the develop in g cham ber,as disclosed,  for examp l e ,  in JP-A -200 1 -1 6 6556. The imag e for ming appar a tus disc losed  in JP-A -2001-166 5 5 6 adopts  ahor izo nta l ta ndem-type ima g e  for mi ng syst emin whic h p lur alpho to sensitive  drums a re  a li gn edin ah orizonta ldir ec tio n and in par allel  toon ea not her tof or m a co lo rimag e o na rec ordi n g s heet by  developi nga gent s.  T he hori zontal tandem -t ype imagefo rmi ng sys t e m suffer s from a problem in tha t  the le ngt h bec omes  long ina d irecti oni n whic h plur al ph ot ose n s itive d ru msar e aligned. T o s olveth is p roblem,  the developing de v ice s which corre spo nd,r e sp ect i ve l y,to the p hotosensitive d rums haveto re duce their dim en sions i n the d irect i on in w hich thephotosens it ived r ums  are align ed. To t his end,t he de v el oping  ag ent st or age  cham ber, w h ich  is n ormall ylocate d adj ac ent to t he developing chamber,is loc atedabo ve the de vel o pin g chamber  asdisclosedinJP- A-200 1-1 6 6556. 
The de vel o pingdevi c e disclos e dinJ P -A -2001-16655 6 c anuse g rav i ty todown wardly move the d e veloping agent  fro m the  de v elop in g agent storag e c ha m b er to th edevelopingchamber,  t h ereby  suppl ying t he deve l o pi n g agen t to  th e feeding  ro ll e r and t he  d e velopi ng r ol ler.
H owever ,  sin c e  the developingagent i s onl y  mo ved d ow nwardly from  the devel oping agent  stora ge c hambe r to th edevelo pin gchamber in a one-way  dire ction,re peti tio n of d evel o p mentresu lt s i n increas e in ara t ioof d eteri or ated  developi n g agentint he deve lo pin g chambe r .I n  particula r,by fr e s h developi n g ag e nt being  addit ionall y suppl i edan d force d i n t o the dev eloping c h amb er  dow nwardlyfr om t he  de ve loping agent st orage ch amber, t h e  deter ior a tedd evelop in g agent is a ccumu la t ed at l o n git udinale ndpor tio ns o f t he d e veloping roller in the d evel oping cha mber.  Theac cumulate d  dev elopinga gent is likel y to lower theq ual i ty o f a n  i ma ge consid era b ly at  bot h e nd p ort ions o f th e  ima g e
 to_the optical_confinement factor Γa. A_limitation inherent_in_edge emitters,_however,_is a low_beam quality. Besides,_in a number of_applications, a narrow_spectral_linewidth is significant, in which case the massively longitudinally multimode nature of edge emitting_laser_light is_a_disadvantage._Hence, there is a need_for a better laser. An_image forming_apparatus for forming an image on a recording_sheet_includes a developing_device for supplying a developing agent to a surface_of a photosensitive element. The developing_device is generally_configured_to_have a developing agent_storage chamber and a developing chamber_that can communicate with each other_via a supplying port. A developing agent_supplying roller and a developing roller_are accommodated in the developing_chamber.
The image_forming apparatus, in some cases,_has to dispose_the developing_device therein such_that the developing agent storage chamber_is located above_the developing chamber, as disclosed, for_example,_in JP-A-2001-166556. The_image_forming_apparatus disclosed_in JP-A-2001-166556 adopts_a_horizontal tandem-type_image_forming system in which plural photosensitive_drums_are aligned in a horizontal direction and_in parallel to one_another_to form a color_image on a recording sheet_by developing agents. The horizontal tandem-type_image forming_system suffers_from a problem in that the length becomes long in a_direction in which plural photosensitive drums_are aligned.
To solve this_problem, the_developing_devices which correspond,_respectively,_to the_photosensitive drums have to reduce their dimensions_in the_direction in which the photosensitive drums_are aligned. To this_end,_the developing agent storage chamber, which_is normally located adjacent to the_developing chamber, is located above_the_developing_chamber as disclosed in JP-A-2001-166556.
The_developing device disclosed in JP-A-2001-166556 can_use gravity to_downwardly move the developing agent from the_developing_agent storage chamber to the developing_chamber,_thereby supplying the developing agent to_the_feeding_roller and the developing roller.
However,_since the developing agent is only_moved downwardly from the developing agent storage chamber to_the developing chamber_in a one-way direction, repetition_of_development_results in increase in a ratio of deteriorated developing agent_in the_developing chamber. In_particular, by fresh developing agent being additionally supplied and forced_into the developing chamber downwardly from the_developing agent storage chamber, the deteriorated developing agent is accumulated at_longitudinal end portions of the developing roller in_the developing chamber. The accumulated developing agent_is likely to lower_the_quality of an image considerably at both_end_portions_of_the image