Position encoding system and method using a composite codestrip

A position encoding system for use in positioning a carriage of a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis, carrying apparatus for forming or sensing marks on the sheet;
• said position encoding system comprising:
• an elongated encoder-strip substrate that has a height, and has top and bottom edges, and is for tensioning across such chassis;
• and
• an elongated polymeric encoder-strip scale secured to the substrate for tensioning therewith across such chassis;
• and wherein:
• the scale has indicia exposed for use in determining such carriage position with respect to such chassis, and is taller than the height of the substrate, and is mounted to overlap both edges of the substrate.

A position encoding system for use in positioning a carriage of a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis, carrying apparatus for forming or sensing marks on the sheet;
• said position encoding system comprising:
• an elongated encoder-strip substrate for tensioning across such chassis;
• and
• an elongated polymeric encoder-strip scale secured to the substrate and for tensioning therewith across such chassis;
• said scale having indicia exposed for use in determining such carriage position with respect to such chassis;
• and
• wherein the substrate is a thin piece of metal having a height, and having thin top and bottom edges;
• and
• further comprising means for guarding the thin edges;
• and wherein the guarding means comprise:
• a height of the polymeric scale that exceeds the height of the substrate;
• and
• mounting of the polymeric scale to extend above the top edge of the substrate and below the bottom edge of the substrate.

A position encoding system for use in positioning a carriage of a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis, carrying apparatus for forming or sensing marks on the sheet;
• said position encoding system comprising:
• an elongated encoder-strip substrate for tensioning across such chassis;
• and
• an elongated polymeric encoder-strip scale secured to the substrate and for tensioning therewith across such chassis;
• said scale having indicia exposed for use in determining such carriage position with respect to such chassis;
• and wherein:
• the substrate has two edges;
• and
• the scale is substantially transparent, and is mounted so that at least part of each of its indicia projects physically beyond at least one substrate edge for transmission therethrough of an optical sensing beam.

A position encoding system for a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis, carrying apparatus for forming or sensing marks on the sheet;
• said position encoding system comprising:
• means, supported from such chassis, for supporting such mark forming or sensing apparatus and driving such carriage across such chassis in a scanning direction;
• an elongated encoder-strip substrate for threading through such carriage, along the scanning direction, and for fastening to such chassis;
• and
• an elongated polymeric encoder-strip scale secured to the substrate and for threading therewith through such carriage;
• said scale having indicia exposed for use in automated reading thereof by such device, for determination of such carriage position with respect to such chassis.

A position encoding system for a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis, carrying apparatus for forming or sensing marks on the sheet;
• said position encoding system comprising:
• means for supporting such mark forming or sensing apparatus and driving such carriage across such chassis in a scanning direction;
• an elongated encoder-strip substrate for threading through the aperture, along the scanning direction, and for fastening to such chassis;
• said substrate being a thin piece of metal having a height, and having thin top and bottom edges;
• and
• an elongated polymeric encoder-strip scale secured to the substrate for threading therewith through such carriage;
• said scale having indicia exposed for use in determining such carriage position with respect to such chassis;
• and
• further comprising means for guarding the thin edges, wherein the guarding means comprise:
• a height of the polymeric scale that exceeds the height of the substrate;
• and
• mounting of the polymeric scale to extend above the top edge of the substrate and below the bottom edge of the substrate.

A position encoding system for a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis carrying apparatus for forming or sensing marks on the sheet;
• said position encoding system comprising:
• an elongated metal encoder-strip substrate that has two ends for securing at opposite sides of such chassis;
• and
• an elongated polymeric encoder-strip scale secured to the substrate and supported thereby;
• said scale being, at all points intermediate to the two ends of the substrate, for use without direct support by the chassis;
• and
• said scale having indicia exposed for use in automated reading thereof by such device, for determination of such carriage position with respect to such chassis.

A position encoding method for use in a large-format automatic image-related device;

• said device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis, carrying apparatus for forming or sensing marks on the sheet;
• and having means for driving the carriage across the chassis in a scanning direction;
• and having an aperture defined, along the scanning direction, in the carriage;
• and having a composite encoder strip that includes a scale, made of a substantially transparent material, secured to a substrate;
• said position encoding method comprising the steps of:
• threading the composite encoder strip through the aperture, along the scanning direction;
• pulling the composite encoder strip taut by applying to the substrate a tension that exceeds a functional failure value for the scale considered alone;
• operating the carriage driving means to scan the carriage across the chassis while the encoder-strip substrate remains threaded through the aperture;
• and
• reading the scale during the operating step by projecting a sensor beam directly through the scale material to determine position of the carriage.

A family of at least two position encoding systems, for use in a corresponding family of at least two large-format automatic image-related devices;

• each of said image-related devices having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis carrying apparatus for forming or sensing marks on the sheet;
• and said family of position encoding systems comprising, in each said position encoding system:
• a respective elongated metal encoder-strip substrate that has two ends secured at opposite sides of such chassis, and
• a respective elongated polymeric encoder-strip scale secured to the substrate and supported thereby, said scale having indicia exposed for use in determining such carriage position with respect to such chassis;
• and wherein
• the substrates in at least two of said position encoding systems are identical to each other;
• and
• the scale and substrate are differently disposed in relation to each other, in said at least two position encoding systems.

A family of at least two position encoding systems, for use in a corresponding family of at least two large-format automatic image-related devices;

• each of said image-related device having a chassis for supporting an image-bearing sheet and having a carriage which scans across the chassis carrying apparatus for forming or sensing marks on the sheet;
• and said family of position encoding systems comprising, in each said position encoding system:
• a respective elongated metal encoder-strip substrate that has two ends secured at opposite sides of such chassis, and
• a respective elongated polymeric encoder-strip scale secured to the substrate and supported thereby, said scale having indicia exposed for use in determining such carriage position with respect to such chassis;
• and wherein
• the scales in at least two of said position encoding systems are identical;
• and
• the scale and substrate are differently disposed in relation to each other, in said at least two position encoding systems.