SPRINGFIELD — All 44 House Republicans signed a resolution to oppose a graduated income tax, saying voters should also oppose it because they’ll have to pay more in taxes.The House Republicans unanimously said they are against changing the tax system in Illinois — and some went as far as saying they refuse to negotiate the matter.Gov. J.B. Pritzker campaigned on a promise to implement a graduated income tax — which he calls a “fair tax” — and has continued the conversation into his …