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Lexmark 5000 Printheads and Nozzle Layout
Arrangement of nozzles on the printheads
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The n nozzles on a "pen" (as H-P call the individual colour elements of a printer cartridge) are arranged in two parallel vertical columns. The column on the left (facing the page) is the even numbered column. The horizontal separation between these columns of nozzles is known (in this software) as the head separation, whereas it should probably be called the column separation. This seems to be constant at 16 pixels for the 5000. If the even column is at pixel 1, the odd column will be at pixel 18, not 17. Update! Bzzzzt. Wrong! It seems that I was a bit premature here. I have revised this to a more sensible column difference, motivated by by support for 300dpi modes. In the latest versions of the code, if the even column is at pixel 1, the odd column will be at pixel 17. The separation between each nozzle in a column is 1/300th of an inch. The nozzles in each column are vertically equidistant from their neighbours in the other column; hence the vertical separation between nozzles is 1/600th of an inch. |
When a data swathe, or swipe, is printed, a single column of data containing a sequence of bits for nozzles 0 to n-1, inclusive, is fed to the printhead. Alternate bits, therefore, print simultaneously from alternate columns of nozzles on the printhead, even and odd. As a consequence, the even and odd bits from a single column of data fed to the printhead will be separated by the column separation gap of 16 pixels.
In order to print a column one pixel wide and the height of the pen at the leftmost print position, I must issue a command to print 1 + column separation + 1 columns of data. The data for the first column will contain only the odd bits, followed by column separation blank columns, followed by a column in which only the even bits are printed.
The black pen
v Alignment B
--- +-----+ ---
^ | | --- +-----+ ---
| | | ^ | | ^
| | | | | |
| | | | | |
| | | | | |
| | | | |
208 | K | | K | 192
| | | | |
| | | | | |
| | | | | |
| | | | | |
| | | | | v
v | | +-----+ ---
--- +-----+
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The black pen is the single pen on the black cartridge. It has 208 nozzles. It may be driven in a mode in which only 192 nozzles are activated, for greater compatibility with the standard colour cartridge. In uni-directional printing, the normal print direction for the black cartridge is left-to-right. The black cartridge occupies the left cradle position. When the photo cartridge is used, it replaces the black cartridge. |
The standard colour pens
+-----+ -- ---
| | ^ ^
| C | 64 |
| | v v |
+-----+ -- -- |
24 |
+-----+ -- -- |
| | ^ ^ |
| M | 64 240
| | v v |
+-----+ -- -- |
24 |
+-----+ -- -- |
| | ^ ^ |
| Y | 64 |
| | v v
+-----+ -- ---
|
There are three pens on the colour cartridge; cyan, magenta and yellow in order from the top of the cartridge. Each pen has 64 nozzles, for a total nozzle count of 192. Between each pen is a gap equivalent to 24 nozzles. The total span from the top cyan nozzle to the bottom yellow nozzle is therefore equivalent to 240 nozzles. In uni-directional printing, the normal print direction for the colour cartridge is right-to-left. The colour cartridge occupies the right cradle position at all times. |
The photo colour pens
+-----+ -- ---
| | ^ ^
| C | 64 |
| | v v |
+-----+ -- -- |
24 |
+-----+ -- -- |
| | ^ ^ |
| M | 64 240
| | v v |
+-----+ -- -- |
24 |
+-----+ -- -- |
| | ^ ^ |
| Y | 64 |
| | v v
+-----+ -- ---
|
This diagram is pure speculation. At this time I have almost no information about the photo cartridge. The photo cartridge replaces the black cartridge in the left cradle position. |
The relationship between black & colour pens
v Alignment B +-----+ -- ---
--- +-----+ --- v | | ^ ^
^ | | --- +-----+ --- -- | C | 64 |
| | | ^ | | ^ 40 | | v v |
| | | | | | -- +-----+ -- -- |
| | | | | | ^ 24 |
| | | | | | +-----+ -- -- |
| | | | | | | ^ ^ |
208 | K | | K | 192 | M | 64 240
| | | | | | | v v |
| | | | | | +-----+ -- -- |
| | | | | | v 24 |
| | | | | | -- +-----+ -- -- |
| | | | | v 40 | | ^ ^ |
v | | +-----+ --- -- | Y | 64 |
--- +-----+ ^ | | v v
+-----+ -- ---
|
As noted above, the black cartridge is to the left of the colour. The key to the horizontal alignment of the two cartridges is the alignment value B. This value is ascertained by printing the cartridge alignment page (which is currently only available under Windows, but which will shortly be available for linux.) |
The alignment printout for black & colour cartridge gives four values; A, B, C & D. A is the pixel value for horizontal alignment of the two cartridges; B is the vertical alignment value, in nozzles; C is the horizontal adjustment for black bi-directional printing; and D is the horizontal adjustment for colour bi-directional printing.
Each swipe printing command contains the A and B values. When the black cartridge is used in 192 nozzle mode, the alignment B value is automatically applied. This has the effect of mapping nozzle B from the full set of 208, onto nozzle 0 of the set of 192. N.B. If alignment B is an odd number, the mapping of EVEN and ODD nozzles to the left and right columns, respectively, will be reversed. E.g., the current vertical alignment on my cartridges is 5, so in 192 nozzle mode, nozzle 0 is actually nozzle 5, hence it is in the right column of the cartridge. This reversal must be handled in the software.
The result of applying the B adjustment is that the vertical relationship between the colour pens and the 192 black nozzles is as shown in the diagram; the black nozzles overlap the cyan and yellow pens by 40 nozzles. Obviously, knowing the alignment B value also allows the programmer to map the 208 nozzles of the full set to their corresponding colour pen nozzles.
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Last modified: Fri Dec 31 22:15:48 EST 1999