Process direction streak source diagnosis in printers

A method comprising:

• printing a multi-color test pattern using a printing device having different printing elements, to create a multi-color printed test pattern, each of said printing elements printing a single color;
• scanning said printed test pattern to produce a scanned image;
• correcting alignment of said scanned image to remove rotation, skew, and translation from said scanned image to produce a corrected scanned image using a computerized device;
• decomposing said corrected scanned image into color blocks using said computerized device;
• creating intensity profiles of said color blocks using said computerized device;
• comparing at least two of said intensity profiles of different colors to determine whether said intensity profiles indicate a correlated printing defect across multiple color separations using said computerized device, said correlated printing defect appearing the same at the same location in at least two of said intensity profiles of said different colors;
• if said intensity profiles have said correlated printing defect indicating, through said computerized device, that a potential defect is located within a common printing element of said printing device;
• and
• if said intensity profiles do not have said correlated printing defect indicating, through said computerized device, that said potential defect is located within one of said different printing elements of said printing device.

A printing device comprising:

• a processor;
• at least one graphic user interface operatively connected to said processor;
• at least one marking engine operatively connected to said processor, said marking engine having different printing elements, and each of said printing elements printing a single color;
• at least one media supply supplying sheets of media to said marking engine;
• and
• at least one scanner operatively connected to said processor,
• said marking engine printing a multi-color test pattern to create a multi-color printed test pattern,
• said scanner scanning said multi-color printed test pattern to produce a scanned image,
• said processor correcting alignment of said scanned image to remove rotation, skew, and translation from said scanned image to produce a corrected scanned image,
• said processor decomposing said corrected scanned image into color blocks,
• said processor creating intensity profiles of said color blocks,
• said processor comparing at least two of said intensity profiles of different colors to determine whether said intensity profiles indicate a correlated printing defect across multiple color separations, said correlated printing defect appearing the same at the same location in at least two of said intensity profiles of said different colors,
• said graphic user interface indicating that a potential defect is located within a common printing element of said marking engine if said intensity profiles have said correlated printing defect, and
• said graphic user interface indicating that a potential defect is located within one of said different printing elements of said marking engine if said intensity profiles do not have said correlated printing defect.

A computer storage device comprising a non-volatile computer storage medium storing instructions executable by a computer, said instruction causing said computer to perform a method comprising:

• printing a multi-color test pattern using a printing device having different printing elements, to create a multi-color printed test pattern, each of said printing elements printing a single color;
• scanning said printed test pattern to produce a scanned image;
• decomposing said scanned image into color blocks using a computerized device;
• creating intensity profiles of said color blocks using said computerized device;
• comparing at least two of said intensity profiles of different colors to determine whether said intensity profiles indicate a correlated printing defect across multiple color separations using said computerized device, said correlated printing defect appearing the same at the same location in at least two of said intensity profiles of said different colors;
• indicating, through said computerized device, whether a potential defect is located within a common printing element of said printing device or is located within one of said different printing elements of said printing device, depending upon whether said intensity profiles have said correlated printing defect.