HP LaserJet 4100 HP PCL/PJL reference (PCL 5 Printer Language) - Technical Ref - Page 309

Note EN The pen position at the end of the label string depends on whether two successive LB commands concatenate together as though only one label was given. The DV/LO combinations which permit concatenation are: Table 23-35 Text Path DV0 (right) DV1 (down) DV2 (left) DV3 (up) Label Origin LO's 1,2,3, and 11,12,13,21 LO's 3,6,9, and 13,16,19 LO's 7,8,9, and 17,18,19 LO's 1,4,7, and 11,14,17,21 The following two rules determine where the pen is positioned after a label string is drawn. Rule 1 is for DV/LO combinations which permit concatenation; rule 2 clarifies other DV/LO combinations: 1 If a concatenation combination is specified, the pen position is updated to give the normal delta X space between the last character of the first label, and the first character of the second label. For proportional fonts that use a pair-wise spacing table, the pen position is updated using an average delta X space. 2 If a non-concatenation combination is specified, the pen position that existed immediately prior to the LB command is restored. LO, Label Origin 23-65