[Tex/LaTex] Remove headrule from a specific page or from chapter’s title page and keep footrule

fancyhdrheader-footer

i tried this answer here memoir class but does not work in my case,I managed to remove the header but could not remove the headrule, here is my MWE:

\documentclass[10pt,a4paper]{book}
\usepackage{xcolor}
\usepackage{fancyhdr}
\usepackage{etoolbox}
\patchcmd{\chapter}{\thispagestyle{plain}}{\thispagestyle{fancy}}{}{}%to make chapter's first page fancy
\usepackage{fancyhdr}%to add horizental link to header&foofter
\pagestyle{fancy}
\fancyhf{}
\fancyfoot[LE,RO]{\thepage}
\fancyhead[RE]{\footnotesize\itshape header}      
\fancyhead[LO]{\leftmark}
\renewcommand{\footrulewidth}{0.2pt}%the widht of header line
\renewcommand{\headrulewidth}{0.2pt}%the widht of header line
%==========to make chapter title fancy===========
\usepackage{titlesec}
\makeatletter%to make chapter titles fancy
\titleformat{\chapter}[frame]
{\normalfont}{\filright\enspace \@chapapp~\thechapter\enspace}
{20pt}{\Huge\bfseries\filcenter}%20pt the small line that close the box
\titlespacing*{\chapter}
{0pt}{-20pt}{20pt}%{}{between header and box}{space after box}
\makeatother
%====to remove the header====
\fancypagestyle{nofooter}{%
\fancyfoot{}%
}
\fancypagestyle{noheader}{%
\fancyhead{}%
}
\usepackage{lipsum}
\begin{document}
\chapter{Head rule}
\thispagestyle{noheader}%
\lipsum[1]
\section{Head rule}
\lipsum[1]
\end{document}

Figure

Best Answer

you can do it by make width=0

\renewcommand{\headrulewidth}{0.0pt}