Closed graph property and Khalimsky spaces

In the following text for Khalimsky $n-$dimensional space $\mathcal{K}^n$ we show self--map $f:\mathcal{K}^n\to\mathcal{K}^n$ has closed graph if and only if there exist integers $\lambda_1,\ldots,\lambda_n$ such that $f$ is a constant map with value $(2\lambda_1,\cdots,2\lambda_n)$. We also show each self--map on Khalimsky circle and Khalimsky sphere which has closed graph is a constant map. The text is motivated by examples.