Portable printer having automatic print alignment

A portable printer for printing on a roll of paper or label stock comprising:

• a housing having a compartment for receiving the roll and a cover for accessing said compartment;
• two rotatable spindle members in said compartment engageable with the opposing ends of said roll;
• a pair of racks, each said rack being coupled to one of said spindle members and to each other by a gear to enable each of said spindle members to move in opposite directions with respect to a center between the spindle members, in which one of said racks has indicia encoding the position of the spindle member coupled to said rack;
• and
• means for locking the position of said spindle members when said cover is closed.

A method for automatically aligning the printing in a portable printer to the width of a roll of paper or label stock comprising the steps of:

• providing two rotatable spindle members engageable with the opposing ends of said roll, and two racks each one of said racks coupled to one of said spindle members and to each other by a gear to enable each of said spindle members to move in opposite directions with respect to a center between the spindle members;
• providing on one of said racks indicia encoding the position of the spindle member coupled to said rack;
• reading a portion of said indicia representative of the position of the spindle member coupled to the rack having said indicia;
• and
• automatically controlling the alignment of printing by said printer with respect to the width of said roll in accordance with the portion of said indicia read.

A portable printer for printing on a roll of paper or label stock comprising:

• a housing having a compartment for receiving the roll;
• two rotatable spindle members in said compartment engageable with the opposing ends of said roll;
• a pair of racks, each said rack being coupled to one of said spindle members and to each other by a gear to enable each of said spindle members to move in opposite directions with respect to a center between the spindle members, in which one of said racks has indicia encoding the position of the spindle member coupled to said rack;
• a fixed sensor for reading a portion of said indicia representative of the position of the spindle member coupled to the rack having said indicia;
• a printing mechanism in said housing with printing elements in which the printing mechanism is capable of printing on the paper or label stock from said roll;
• and
• a controller for automatically controlling the alignment of printing by said printing mechanism with respect to the width of said roll in accordance with the portion of said indicia read by said sensor.

A portable printer for printing on a roll of paper or label stock comprising:

• a housing having a compartment for receiving the roll;
• means for centering the roll in said compartment;
• means for encoding the position of said centering means representative of the width of said roll;
• means for reading the encoding position of said centering means;
• a printing mechanism in said housing with printing elements in which the printing mechanism is capable of printing on the paper or label stock from said roll;
• and
• means for automatically controlling the alignment of printing by said printing mechanism with respect to the width of said roll in accordance with the read encoded position to prevent use of printing elements outside the width of the roll.

A method for automatically aligning the printing in a portable printer to the width of a roll of paper or label stock comprising the steps of:

• providing a housing having a compartment for receiving the roll;
• centering the roll in said compartment;
• encoding the position of said centering means representative of the width of said roll;
• reading the encoding position of said centering means;
• and
• aligning of printing with respect to the width of said roll in accordance with the read encoded position to prevent printing outside the width of the roll.