Paper transport device for thermal printer

A paper transport device for transporting recording paper through a color thermal printer with a thermal head alternately in a recording direction and in an opposite direction, wherein the thermal head records one color frame at one transport in the recording direction to record at least three color frames in a recording area on the recording paper, the transport device comprising:

• a feed roller device disposed behind the thermal head in the recording direction to transport the recording paper in the opposite direction, the feed roller device comprising a capstan roller and a press member for pressing the recording paper onto the capstan roller;
• a driving device for driving the feed roller device such that the feed roller device continues transporting the recording paper in the recording direction till at least the recording area has passed through the feed roller device;
• and
• a subsidiary press member for pressing the recording paper on the capstan roller, a contact position of the subsidiary press member with the capstan roller having a given angle to that of the press member so as to make the recording paper turn the capstan roller at the given angle.

A method of transporting recording paper through a thermal printer by a feed roller device having a capstan roller around which the recording paper turns by means of at least a press member and a subsidiary press member, and a thermal head which records at least three color frames in a recording area on the recording paper, said feed roller device being disposed behind the thermal head in a recording direction, comprising the steps of:

• A. transporting the recording paper in the recording direction while the thermal head records one color frame;
• B. thereafter continuing transporting the recording paper further in the recording direction till at least the recording area has passed through roller device;
• C. transporting the recording paper in an opposite direction to the recording direction by the feed roller device till the recording area has passed through a heating element array of the thermal head;
• and
• D. repeating steps A to C so as to record at least three color frames in the recording area;
• wherein the recording paper is turned around the capstan roller by a pair of press members for pressing the recording paper onto the capstan roller, the pair of press members being disposed around the capstan roller and spaced in the recording direction, the method further comprising the step of changing a turn angle of the recording paper around the capstan roller by changing contact positions of the press members with the capstan roller in relation to each other.

A paper transport device for transporting recording paper through a color thermal printer with a thermal head alternately in a recording direction and in an opposite direction, wherein the thermal head records one color frame at one transport in the recording direction to record at least three color frames in a recording area on the recording paper, the transport device comprising:

• a feed roller device disposed behind the thermal head in the recording direction to transport the recording paper in the opposite direction, the feed roller device comprising a capstan roller and a press member for pressing the recording paper onto the capstan roller;
• a driving device for driving the feed roller device such that the feed roller device continues transporting the recording paper in the recording direction till at least the recording area has passed through the feed roller device;
• a subsidiary press member for pressing the recording paper on the capstan roller, a contact position of the subsidiary press member with the capstan roller having a given angle to that of the press member so as to make the recording paper turn the capstan roller at the given angle;
• and
• a device which changes the given angle by moving an angular position of the subsidiary press member in relation to the press member.

A method of transporting recording paper through a thermal printer by a feed roller device having a capstan roller around which the recording paper turns, and a thermal head records at least three color frames in a recording area on the recording paper, comprising the steps of:

• A. transporting the recording paper in a recording direction while the thermal head records one color frame;
• B. thereafter continuing transporting the recording paper further in the recording direction till at least the recording area has passed through the feed roller device;
• C. transporting the recording paper in an opposite direction to the recording direction by the feed roller device till the recording area has passed through a heating element array of the thermal head;
• and
• D. repeating steps A to C so as to record at least three color frames in the recording area;
• wherein the recording paper is turned around the capstan roller by a pair of press members for pressing the recording paper onto the capstan roller, the pair of press members being disposed around the capstan roller and spaced in the recording direction, the method further comprising the step of changing a turn angle of the recording paper around the capstan roller by changing contact positions of the press members with the capstan roller in relation to each other.