 matrix. This ensures that when one-stream transmission (rank-one transmission) is performed, all the transmit power may be allocated to the antenna with the strong channel and no power is wasted on the other antenna, which on average will not be able to convey significant power to the receiver. The reason for the latter is because of the cross-polarized setup in conjunction with the selection of rank-one transmission, which means the channel matrix will typically have only one element with a power substantially larger than zero and that element will lie on the diagonal.
All power should hence be allocated to the antenna which corresponds to the aforementioned non-zero diagonal element. For a design which targets a scenario with equal powered channel coefficients, this is however typically not the case. Existing codebook designs do however not address this issue for the case of more than two antennas and also do not consider the structure of the codebook for various transmission ranks. 1. Field of the Invention
This invention relates to an image forming apparatus which forms an image on a transfer material by use of an electrophotographic process, and a charger installed in this image forming apparatus.
2. Description of the Related Art
A corona discharge type fixing device installed in an image forming apparatus using an electrophotographic process is classified broadly into a wire electric discharge type (Corotron, Scorotron, etc.) or pin discharge type (pin electrode, sawtooth electrode, etc.).
In a method generally known, a cleaning member such as felt provided to wrap around a wire electrode is moved in a longitudinal direction (axial direction of a photoconductor drum) of a charger, as a means to clean the wire electric discharge type wire electrode.
Another method is known in which a cylindrical cleaning member provided movably along the sawtooth electrode is moved while being pressed against the edge of the sawtooth electrode, as a means to clean the pin discharge type sawtooth electrode (Jpn. Pat. Appln. KOKAI Publication No. 9-211940).
Still another method is known in which the sawtooth electrode is rotatably provided, and electric discharge products deposited on the edge of the sawtooth electrode are scraped against the cleaning member (Jpn. Pat. Appln. KOKAI Publication No. 11-327265).
Furthermore, apparatuses or methods are known in which a driving force generator such as a motor is used to automatically clean the electrode of the charger (Jpn. Pat. Appln
matrix. This ensures that when one - stream transmission (rank - one transmittance) is perform, all the transmit power may be allocated to the antenna with the strong duct and no power is wasted on the early antenna, which on average will not be able to convey significant ability to the receiver. The reason for the latter is because of the crabbed - polarized setup in conjunction with the selection of rank - one transmittance, which means the channel matrix will typically have only one element with a ability substantially larger than zero and that element will lie down on the diagonal. 
 All power should hence be allocated to the antenna which match to the aforementioned non - zero diagonal element. For a design which targets a scenario with adequate powered channel coefficients, this is however typically not the case. Existing codebook designs do however not address this offspring for the casing of more than two antennas and also do not consider the structure of the codebook for various transmission ranks. 1. Field of the Invention 
 This invention associate to an image forming apparatus which form an image on a transfer material by use of an electrophotographic procedure, and a charger installed in this image forming apparatus. 
 2. Description of the Related Art 
 A corona dismissal type fixing device installed in an image forming apparatus using an electrophotographic summons is classified broadly into a wire electric discharge type (Corotron, Scorotron, etc .) or pin dismissal type (pin electrode, sawtooth electrode, etc .). 
 In a method acting by and large known, a cleaning member such as felt provided to wind around a wire electrode is moved in a longitudinal direction (axile direction of a photoconductor brake drum) of a charger, as a means to clean the telegram electric discharge type wire electrode. 
 Another method is known in which a cylindrical cleaning extremity provided movably along the sawtooth electrode is affect while being pressed against the boundary of the sawtooth electrode, as a means to clean the personal identification number discharge type sawtooth electrode (Jpn. Pat. Appln. KOKAI Publication No. 9 - 211940). 
 even another method is sleep together in which the sawtooth electrode is rotatably provided, and electric discharge products deposited on the edge of the sawtooth electrode are scraped against the cleaning member (Jpn. Pat. Appln. KOKAI Publication No. 11 - 327265). 
 Furthermore, apparatuses or method are known in which a driving military unit generator such as a motor is used to automatically clean the electrode of the charger (Jpn. Pat. Appln
 mahrix. This ensures that wmen one-stream trcbsmissmon (rani-one travsmission) is performed, all tie teansmut power may be allocaged to thv antenna witi the strong chaihel and no poscr is xasted on the ojher antenna, which on averdgd cill not be able to convey significagt powet ho the receivet. The weaskn for the latter is because of ths cross-kolarized setup in conjunction with the seleftioj of rank-one translission, whixh mqqns the chanvel matrix will typicamly have only one element with x powzr substantuaoly narger than zero and that elckent whll lie on the diagonsl.
Anl power should hence be allocated to the wntenna wvieh corresponds to the adoremgntioted vin-zdro dmagknal epemxnt. For a dssign which targets a scenario wynn equal poweded chwngel coefficients, this is however typicanly not the case. Existing xodebook designs do hlwever noe address this issue for the case of more than twm antxnvas akd auwo do not consider the structure of the codebooh fpr various transiission ranls. 1. Gyeld of the Ivvention
Tgis invention relahes to wn imqge formigg alparatus which forms an imate on a tranfder material by usz of an eleccrophojograpnic process, and a chargzr insfalled in tjis image worming apparatur.
2. Dvscrhption of the Related Art
A corona dmschaxge type fixong dedice instapled lt an image forming appatatus gsing an epectrophotographic process is classified broaclf itto a wixe elegtric discharge type (Corotron, Scorotxon, etz.) or pin dpscharge vype (pin elestrode, sawtoodj electrode, xtc.).
In a mqthoe geberally ynown, a cleanimg member such as fwlt provided to wrep atohnd a wire eleccxoee is moved in s lungytldiial dysection (axian difecgoon ow a phoujcivducyor drum) of a charges, as a means to clean yhc wire elgctric difcharge type eire electrode.
Anotjer mxthod ms knoen yn which a cylindrical cleaninf member oroyided movably alokg tre sawtootk electrode is moved while being pressed against the edge if the sawtooth eleetvode, as a meens to clean tha pin discharge type sawtooth electroce (Jpn. Pat. Appln. KOKAJ Publhcatiln No. 9-211940).
Still another method is known in which the sawtooth electrode is roratablb [rovided, ans elrctrib dnsckarge pwodurtr deposited on tne edge of the sawtooth electrove are scrdpzd against the cleaning membet (Gpn. Pat. Appln. KOKAI Publication No. 11-327265).
Fudthermorr, apparatuses or methods are knpwn in which a driving fprce genwratod such as e motor is used to aitomatncally clean rhe clectrode of tfe vhwrger (Jpn. Pat. A'pln
matrix. This ensures that when one-stream transmission is all the power may be the channel and no is wasted on other antenna, which on average will be able to convey significant power to the receiver. The reason for the is because of the cross-polarized setup in conjunction with the selection of rank-one which the matrix typically have only one element with a power substantially larger than zero and that element will on the diagonal. All power should hence be to the antenna which to the aforementioned non-zero diagonal For design which a with powered channel coefficients, is however typically not the case. Existing codebook designs do however not address this issue for the of more antennas and do consider structure of the various transmission ranks. 1. Field of invention relates to an image forming apparatus which an image a transfer material by use of electrophotographic process, and a charger installed in this forming apparatus. 2. Description of the Related Art A corona discharge type fixing device installed image forming apparatus using electrophotographic process is broadly a electric type (Corotron, etc.) or pin discharge type (pin electrode, sawtooth electrode, etc.). In method generally known, a cleaning member such as felt provided around wire electrode is in a longitudinal direction direction a photoconductor drum) of as means wire discharge wire electrode. Another method known in which a cylindrical member provided movably along while being pressed against the edge of the electrode, as a means to clean the discharge type sawtooth electrode (Jpn. Pat. Appln. KOKAI Publication No. 9-211940). Still method is which the sawtooth electrode is rotatably provided, and discharge products deposited on edge of the sawtooth electrode are scraped against the member Pat. Appln. Publication No. 11-327265). apparatuses or methods known in which force generator as motor automatically clean the electrode of the (Jpn. Appln
 matrix. This ensures that when One-stream tRansmIssIon (RaNk-onE traNsmission) is perFOrmeD, all the transmit power maY be alLoCAted TO tHe antEnna witH ThE STroNg ChAnnEl ANd No powEr iS wasted On the other AntEnNa, which on aveRAgE will not be AblE to convey sigNifIcant pOwEr tO The reCeiVer. ThE reasoN For the Latter is bEcAUse of tHE cross-pOLArIzed Setup in conjunctioN WiTH the selection oF rank-oNe TRaNSMisSioN, which meanS tHe chaNNel matrIX wILL TypICally have only One element wITh a Power sUbStaNTially LargeR tHAn zEro and that eLemeNt will lie On the dIAgonal.
ALL power sHould hEncE be AlloCAtEd To tHe ANteNNa WhiCH coRrespondS tO tHe afoRemeNTIONed nOn-zEro dIagonAl element. For a DesIgn wHIch TargeTs a scEnarIo With eQual poWered ChAnnel coefficienTs, thIs is howevEr tYpIcaLlY not tHE case. EXisTinG codeboOk desigNS do HoWEVEr Not address this issuE fOR ThE case of mOre thaN TwO aNTennas anD aLso Do noT COnsidEr thE StRucture oF the coDEbOoK for varIoUs tranSmIssIon Ranks. 1. fIeld Of the INvention
this iNVention relates TO an image formiNG aPPArATus wHicH forms an imaGe on A TranSfer MAtEriAL by usE of an ElECtROphotographic procesS, aNd a chaRger iNstalled in thiS image formING ApparatuS.
2. DesCRiPTion of the RelatEd Art
a corona disCHarge typE fixiNg device Installed IN An image fOrmIng AppAraTUS uSing an electroPHOtogRaPhic proCesS is clasSifIed BroAdlY iNto a wire eLectric dIsChArGe TypE (CoroTRon, ScoroTrOn, eTc.) Or pIn disCHarge tYpe (piN eleCtRoDE, saWtooth eLEcTROde, eTc.).
in A metHod GeNeralLy knOWn, a CleaninG member suCh aS Felt PrOvIded to wRap around a wirE eLectrode is MoVed In a lonGITudinal dIrection (axial direction oF A photocOndUctor Drum) Of a chargeR, as A means To cLEan the Wire elEctriC dIscHARge tyPE WiRe eLeCtrode.
AnotHER meThod iS kNown In which A cylindrical cleaniNG meMber provided mOvaBly aLONg The SAwTOotH eLEctRODe is moved while bEing presseD aGAiNst the edge OF thE sAwtooth ElectroDe, as a MEans to cLean the piN dischargE tYpe sAWTooTh electrodE (Jpn. Pat. APpln. KOKAI pUblicATiOn No. 9-211940).
STilL anothEr MetHod is Known iN WhiCh the SawtooTh ElectrOde is RoTatably pRovided, and electric dischArge prOductS dePosited on The EDge Of the sawtOoth Electrode aRe sCraPed agAinST the cLeanINg MemBEr (Jpn. pat. APPln. KOKAI PUBlIcaTIOn no. 11-327265).
FurthermoRE, APpaRatusEs oR MethodS are Known in which a drivINg force generatOr suCH As a MotOR is uSeD to automaticalLy cLeAN The electRoDe of the charGer (Jpn. PaT. APPln
 matrix. This ensures that  when one- strea m t ran sm issi on ( rank-one trans m issi on) is performed, allthe t ra n smit po wer m ay be a l lo c a ted  t othe  a n te nna w ith  the st rong chann elan d no power i s  w asted on t heother antenn a,whichon  av e ragewil l not  be ab l e to c onvey sig ni f icantp ower to t he  rec eiver. The reason fo r  the latter is  becau se of t hecro ss-polariz ed  setu p  in con j un c t i onw ith the selec tion of ran k -on e tran sm iss i on, wh ich m ea n s t he channelmatr ix will t ypical l y haveo nly one  eleme ntwit h ap ow er  su bs t ant i al lyl arg er thanze ro  andthat e l e ment  wi ll l ie on  the diagonal .
A ll p o wer  shou ld he ncebe  allo catedto th eantenna which c orre sponds to  th eafo re menti o ned no n-z ero  diagon al elem e nt.  F o r adesign which targe ts a  s cenariowith e q ua lp owered c ha nne l co e f ficie nts, th is is ho wevert yp ic ally no tthe ca se . E xis tingc odeb ook de signs do  howe v er not address this issue fo r  t h e  c a se o f m ore than tw o an t enna s an d  a lso do no t con si d er the structure of th ecodebo ok fo r various tra nsmissionr a n ks. 1. F ield of the InventionThisinventionr elates t o animage fo rming app a r atus whi chfor msani m ag e on a transf e r  mat er ial byuse  of anele ctr oph oto gr aphic pro cess, an dach ar ger  inst a lled inth isim age  form i ng app aratu s.
2 .De s cri ption o f  t h e  Rel at ed  Art 
Aco ronadisc h arg e typefixing de vic e  ins ta ll ed in a n image formi ng  apparatus  u sin g an e l e ctrophot ographic process is cla s sifiedbro adlyinto  a wire e lec tric d isc h arge t ype (C orotr on , S c o rotro n ,  e tc. )or pin dis c h arg e typ e(pin  electr ode, sawtooth elec t rod e, etc.).
Ina m etho d ge ner a ll y  kn ow n , a c leaning membersuch as fe lt pr ovided tow rap  a round a  wire e lectr o de is m oved in a  longitud in al d i r ect ion (axial  directi on of a p h otoco n du ctordru m) ofacha rger,  as am ean s tocleanth e wire  elec tr ic disch arge type wire electrod e.
Ano thermet hod is kn own inwhich a c ylin drical cle ani ngmembe r p r ovide d mo v ab lya longthes awtooth e l ec tro d e  i s moved whi l e bei ng pr ess e d agai nstthe edge of the s a wtooth electro de,a s  amea n s to  c lean the pin d isc ha r g e type s aw tooth elect rode (Jp n. Pat.Appln.  KOKAI  Public a t io n  No. 9 -211 940 ).
Stillano th e r metho dis knownin w hi ch the  sawto o th e l e ctrode is rotata bly p r o vided ,  an d ele ct ric dis c harg e products  depositedon the  edg e ofthe saw to oth el ect ro de are scr a ped again st th e clean in g me mbe r (Jpn . Pa t .  Appl n. K OK AIPublicati o n  N o .11 - 327 265) .
Fur th ermo re, appar a tuses or  me t hods ar ekno w n  in wh i ch a  driving f orc e gen e r ator sucha s am ot o r isused t o auto matical l y c le an theele c t rode of t he charge r  (J pn . Pa t. Appln 
 matrix._This ensures_that when one-stream transmission_(rank-one transmission)_is_performed, all_the_transmit power may_be allocated to_the antenna with the_strong channel and_no_power is wasted on the other antenna, which on average will not be able_to_convey significant_power_to_the receiver. The reason for_the latter is because of_the cross-polarized_setup in conjunction with the selection of rank-one_transmission,_which means the_channel matrix will typically have only one element with_a power substantially larger than zero_and that element_will_lie_on the diagonal.
All power_should hence be allocated to the_antenna which corresponds to the aforementioned_non-zero diagonal element. For a design which_targets a scenario with equal powered_channel coefficients, this is however_typically not_the case. Existing codebook designs_do however not_address this_issue for the_case of more than two antennas_and also do_not consider the structure of the_codebook_for various transmission_ranks._1._Field of_the Invention
This invention_relates_to an_image_forming apparatus which forms an image_on_a transfer material by use of an_electrophotographic process, and a_charger_installed in this image_forming apparatus.
2. Description of the_Related Art
A corona discharge type fixing_device installed_in an_image forming apparatus using an electrophotographic process is classified broadly into_a wire electric discharge type (Corotron,_Scorotron, etc.) or pin_discharge type_(pin_electrode, sawtooth electrode,_etc.).
In_a method_generally known, a cleaning member such as_felt provided_to wrap around a wire electrode_is moved in a_longitudinal_direction (axial direction of a photoconductor_drum) of a charger, as a_means to clean the wire_electric_discharge_type wire electrode.
Another method is_known in which a cylindrical cleaning_member provided movably_along the sawtooth electrode is moved while_being_pressed against the edge of the_sawtooth_electrode, as a means to clean_the_pin_discharge type sawtooth electrode (Jpn._Pat. Appln. KOKAI Publication No. 9-211940).
Still_another method is known in which the sawtooth electrode_is rotatably provided,_and electric discharge products deposited_on_the_edge of the sawtooth electrode are scraped against the cleaning_member (Jpn._Pat. Appln. KOKAI_Publication No. 11-327265).
Furthermore, apparatuses or methods are known in which_a driving force generator such as a_motor is used to automatically clean the electrode of the charger_(Jpn. Pat. Appln