Color thermal printer and color thermal printer method

A method of printing a full-color image on a recording material by a thermal printer while transporting the recording material through a transport path one time, the thermal printer having a paper supply mechanism for supplying the recording material, at least first to third printing stages and an ejection mechanism for cutting and ejecting the recording material which are arranged along the transport path in this order from upstream, each of the printing stages for recording a particular color frame of the full-color image and comprising a thermal head and a platen which are disposed across the transport path to be movable relative to each other, the recording material being nipped between the thermal head and the platen in each of the printing stages prior to starting recording the particular color frame, the method comprising the steps of:

• providing slacks in the recording material between the paper supply mechanism and the first printing stage, between the first to third printing stages, and between the third printing stage and the ejection mechanism;
• transporting the recording material through one of the paper supply mechanism, the first to third printing stages and the election mechanism at a first speed;
• measuring respective amount of the slacks;
• and
• controlling transporting speeds of the recording material through other of the paper supply mechanism, the first to third printing stages and the ejection mechanism based on the amounts of the slacks, so as to maintain the amounts of the slacks in a predetermined range.

A method of printing a full-color image on a recording material by a thermal printer while transporting the recording material through at least first to third printing stages one time, which are arranged along a transport path in this order from upstream, each of the printing stages for recording a particular color frame of the full-color image and comprising a thermal head and a platen which are disposed across the transport path to be movable relative to each other, the recording material being nipped between the thermal head and the platen in each of the printing stages prior to starting recording the particular color frame, the method comprising the steps of:

• A. transporting a leading edge of the recording material from the first printing stage to the second printing stage;
• B. stopping the leading edge in the second printing stage while continuing to transport the recording material through the second printing stage until a second slack of a first amount is formed between the first printing stage and the second printing stage;
• C. transporting the leading edge of the recording material from the second printing stage to the third printing stage;
• D. stopping the leading edge in the third printing stage while continuing to transport the recording material through the second printing stage until a second slack of a second amount is formed between the second printing stage and the third printing stage;
• and
• E. maintaining the first and second amounts of the first and second slacks, respectively, within a fixed range.

A method of printing a full-color image on a recording material by a thermal printer while transporting the recording material through a transport path one time, the thermal printer having at least first to third printing stages arranged along the transport path in this order from upstream, each of the printing stages for recording a particular color frame of the full-color image and comprising a thermal head and a platen which are disposed across the transport path to be movable relative to each other, the recording material being nipped between the thermal head and the platen in each of the printing stages prior to starting recording the particular color frame, the method comprising the steps of:

• A. transporting a leading edge of the recording material through the second printing stage at a lower speed than a transporting speed for the leading edge through the first printing stage, to provide a first slack in the recording material between the first and the second printing stages;
• B. transporting the leading edge of the recording material through the third printing stage at a lower speed than the transporting speed for the leading edge through the second printing stage, to provide a second slack in the recording material between the second and the third printing stages;
• C. measuring respective amounts of the first and second slacks;
• D. resetting the transporting speeds through the first to third printing stages to be equal to each other after the slacks reach a predetermined amount;
• and
• E. maintaining the first and second slacks in a range around the predetermined amount while the thermal heads execute recording.

A color thermal printer for printing a full-color image on a recording material while transporting the recording material through a transport path one time, the thermal printer having at least first to third printing stages arranged along the transport path in this order from upstream, each of the printing stages for recording a particular color frame of the full-color image and comprising a thermal head and a platen which are disposed across the transport path to be movable relative to each other, the recording material being nipped between the thermal head and the platen in each of the printing stages prior to starting recording the particular color frame, the color thermal printer comprising:

• first to third transporting devices for transporting the recording material through the first to third printing stages, respectively;
• a first slack sensor for measuring an amount of first slack formed between the first and second transport devices;
• a second slack sensor for measuring an amount of second slack formed between the second and third transport devices;
• and
• control means for controlling the first transporting device in accordance with an output from the first slack sensor, and controlling the third transporting device in accordance with an output from the second slack sensor.

A color thermal printer for printing a full-color image on a recording material while transporting the recording material through a transport path one time, the thermal printer having at least first to third printing stages arranged along the transport path in this order from upstream, each of the printing stages for recording a particular color frame of the full-color image and comprising a thermal head and a platen which are disposed across the transport path to be movable relative to each other, the recording material being nipped between the thermal head and the platen in each of the printing stages prior to starting recording the particular color frame, the color thermal printer comprising:

• first to third transporting devices for transporting the recording material through the first to third printing stages, respectively;
• an ejection mechanism which is disposed in a downstreammost position of the transport path for cutting and ejecting the recording material;
• a fourth transporting device for transporting the recording material through the ejection mechanism;
• and
• control means for controlling the first to fourth transporting devices so as to provide the recording material with first and second slacks between the first to third printing stages, and a third slack before the ejection mechanism.