There were two factories owned by different Fischers in Budapest, Hungary: [i]Emil von Fischer[/i] (later became [i]Fischer’sche Keramische Fabrik[/i]) and that of [i]ignatz Fischer[/i]. Hold in mind that Hungary was formerly part of the Austro-Hungarian Empire, thus German language was common..

In your case, the name [i]Ignatz[/i] was shortened to the initial ‘J’. The PM&M website has an explanation in its vocabulary section:
[url=https://www.porcelainmarksandmore.com/resources/vocabulary/consovowel.php]https://www.porcelainmarksandmore.com/resources/vocabulary/consovowel.php[/url]