ticket_venta/account_invoice_patch.py

from openerp.osv import osv

class account_invoice(osv.osv):
    _inherit = 'account.invoice'

    def print_ticket_ferreteria(self, cr, uid, ids, context=None):
        return {
            'type': 'ir.actions.report.xml',
            'report_name': 'ticket_venta.report_ticket_ferreteria',
            'datas': {'ids': ids},
            'nodestroy': True
        }