Hide report link

Typically, all reports will be appeared on Print drop-down list on all screens.
If you want to hide a specific report, just only inherit report and append this line:
     menu = "False"
Example:
    <report
            id="sale.report_sale_order"
            string="Quotation / Order"
            model="sale.order"
            report_type="qweb-pdf"
            file="sale.report_saleorder"
            name="sale.report_saleorder"
            menu="False"
   />