Color direct thermal printing method and thermal head of thermal printer

• US 5,729,274 A
• Filed: 04/17/1996
• Issued: 03/17/1998
• Est. Priority Date: 11/05/1992
• Status: Expired due to Fees

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Sato, Masamichi
• Primary Examiner(s): TRAN, HUAN HUU
• Application Number:
  US08/633,557
• Time in Patent Office: 699 Days
• Field of Search: 347/173, 347/175, 400/120.02, 400/120.03
• US Class Current: 347/173
• CPC Class Codes: B41J 2/32 using thermal heads

Abstract

A color thermal recording medium has three thermosensitive coloring layers for cyan, magenta and yellow formed in this order from the base material side. The upper layer has a higher thermal recording sensitivity. The color thermal recording medium is thermally recorded by three thermal heads by a one-pass method. At least two of the three thermal heads are driven in time-sharing fashion. Besides, drive voltage for the thermal heads for recording uppermost and next uppermost thermosensitive coloring layers are set lower than that applied for the thermal head for the innermost thermosensitive coloring layer. Instead of or in addition to adjusting the drive voltages, the maximum duration of drive times may be changed for each color.

Claims

1. A color thermal printing method for printing a multi-color image comprising the steps of:

passing a color thermal recording medium once through a transport path along which first to third thermal heads and first and second light sources are arranged, the color thermal recording medium having first to third thermosensitive coloring layers each developing a different color,

the first to third thermosensitive coloring layers being arranged in a predetermined order having the first thermosensitive coloring layer being an uppermost layer and the third thermosensitive coloring layer being a lowermost layer with the second thermosensitive coloring layer being disposed between the first and third thermosensitive coloring layers;

thermally recording the first thermosensitive coloring layer using the first thermal head;

optically fixing the first thermosensitive coloring layer by radiating electromagnetic rays specific to the first thermosensitive coloring layer from the first light source;

thermally recording the second thermosensitive coloring layer using the second thermal head;

optically fixing the second thermosensitive coloring layer by radiating electromagnetic rays specific to the second thermosensitive coloring layer from the second light source;

thermally recording the third thermosensitive coloring layer using the third thermal head; and

driving the first to third thermal heads in time-sharing fashion such that respective driving times of the first, second and third thermal heads for thermally recording the first, second and third thermosensitive coloring layers are shifted from one another so as not to overlap with one another, thereby reducing maximum instantaneous power consumption of said driving step.

2. The color thermal printing method according to claim 1, further comprising the step of:

setting a condition of E1<

E2<

E3, where E1 is a voltage to be applied to the first thermal head, E2 is a voltage to be applied to the second thermal head, and E3 is a voltage to be applied to the third thermal head.

3. The color thermal printing method according to claim 1, further comprising the step of:

setting a condition of T1<

T2<

T3, where T1 is a maximum duration of a driving time of the first thermal head, T2 is a maximum duration of the driving time of a second thermal head, and T3 is a maximum duration of a driving time of the third thermal head.

4. The color thermal printing method according to claim 3, wherein voltages applied to the first to third thermal heads are a same value.

5. The color thermal printing method according to claim 3, wherein voltages applied to the first to third thermal heads are different in value from each other.

6. A color thermal printer for printing a multi-color image comprising:

a transport path through which a color thermal recording medium passes once;

first to third thermal heads arranged along said transport path, the color thermal recording medium having first to third thermosensitive coloring layers each developing a different color,

the first to third thermosensitive coloring layers being arranged in a predetermined order having the first thermosensitive coloring layer being an uppermost layer and the third thermosensitive coloring layer being a lowermost layer with the second thermosensitive coloring layer being disposed between the first and third thermosensitive coloring layers;

a first light source arranged along said transport path, which optically fixes the first thermosensitive coloring layer after the first thermosensitive coloring layer has been thermally recorded using the first thermal head, said first light source radiating electromagnetic rays specific to the first thermosensitive coloring layer;

a second light source, arranged along said transport path, which optically fixes the second thermosensitive coloring layer after the second thermosensitive layer has been thermally recorded using the second thermal head, said second light source radiating electromagnetic rays specific to the second thermosensitive coloring layer, and wherein finally the third thermosensitive coloring layer is thermally recorded using the third thermal head; and

driving means for driving the first to third thermal heads in time-sharing fashion such that driving times of the first to third thermal heads are mutually exclusive, thereby reducing maximum instantaneous power consumption of said driving means.

7. The color thermal printer according to claim 6, wherein each of the first to third thermal heads includes a number of heating elements arranged in a line in a direction perpendicular to said transport path, the color thermal printer further comprising:

moving means for moving the color thermal recording medium by one line amount each time the first to third thermal heads complete recording respective color pixels of one line allocated to each of the first to third thermal heads.

8. The color thermal printer according to claim 7, wherein one of said first and second light sources is provided between two of the first to third thermal heads.

9. The color thermal printer according to claim 8, wherein each of the first to third thermal heads extends in a direction perpendicular to a surface of the color thermal recording medium so as to shield electromagnetic rays.

10. The color thermal printer according to claim 9, wherein the first thermosensitive coloring layer is a yellow thermosensitive coloring layer, the second thermosensitive coloring layer is a magenta thermosensitive coloring layer, and the third thermosensitive coloring layer is a cyan thermosensitive coloring layer.

11. The color thermal printer according to claim 10, wherein the yellow thermosensitive coloring layer is optically fixed by ultraviolet rays of substantially 420 nm, and the magenta thermosensitive coloring layer is optically fixed by ultraviolet rays of substantially 365 nm.

12. The color thermal printer according to claim 11, wherein each of the first to third thermal heads is supplied with a bias pulse for heating a respective thermosensitive coloring layer to a temperature just near to a coloring temperature and image pulses corresponding in number to a coloring density, for thermally recording one pixel.

13. A color thermal printer according to claim 12, further comprising:

means for setting a condition of E1<

E2<

E3, where E1 is a voltage to be applied to the first thermal head, E2 is a voltage to be applied to the second thermal head, and E3 is a voltage to be applied to the third thermal head.

14. The color thermal printer according to claim 12, further comprising:

means for setting a condition of T1<

T2<

T3, where T1 is a maximum duration of the driving time of the first thermal head, T2 is a maximum duration of the driving time of the second thermal head, and T3 is a maximum duration of the driving time of the third thermal head.

15. The color thermal printer according to claim 6, wherein at least two of the first to third thermal heads have high heat-restraining properties.

16. The color thermal printer according to claim 15, wherein each of the first to third thermal heads comprises:

a base plate;

a plurality of heating elements formed on said base plate, each of said plurality of heating elements having a resistance layer and a pair of electrodes connected to said resistance layer; and

a partial glazed glass layer formed between said base plate and each of said plurality of heating elements, said partial glazed glass layer having a semi-cylindrical shape, and having a thickness enough for restraining heat energy therein an appropriate time after the heat energy is radiated from said resistance layer, thereby reducing temperature decay of each of said plurality of heating elements after a driving time of the first to third thermal heads.

17. A color thermal printer for printing a multicolor image comprising:

a transport path through which a color thermal recording medium passes once;

first to third thermal heads arranged along said transport path, the color thermal recording medium having first to third thermosensitive coloring layers each developing a different color,

the first to third thermosensitive coloring layers being arranged in a predetermined order having the first thermosensitive coloring layer being an uppermost layer and the third thermosensitive coloring layer being a lowermost layer with the second thermosensitive coloring layer being disposed between the first and third thermosensitive coloring layers;

a first light source arranged along said transport path, which optically fixes the first thermosensitive coloring layer after the first thermosensitive coloring layer has been thermally recorded using said first thermal head, said first light source radiating electromagnetic rays specific to the first thermosensitive coloring layer;

a second light source arranged along said transport path, which optically fixes the second thermosensitive coloring layer after the second thermosensitive coloring layer has been thermally recorded using said second thermal head, said second light source radiating electromagnetic rays specific to the second thermosensitive coloring layer, and wherein finally the third thermosensitive coloring layer is thermally recorded using said third thermal head;

driving means for driving said first to third thermal heads in time-sharing fashion such that driving times of said first to third thermal heads are mutually exclusive, thereby reducing maximum instantaneous power consumption of said driving means,

one of said first and second light sources being provided between two of said first to third thermal heads,

each of said first to third thermal heads having high heat restraining properties, having a number of heating elements arranged in a line in a direction perpendicular to said transport path, and extending in a direction perpendicular to a surface of the color thermal recording medium to shield the electromagnetic rays radiated by said first light source from the electromagnetic rays radiated by said second light source; and

moving means for moving the color thermal recording medium by one line amount each time said first to third thermal heads complete recording respective color pixels of one line allocated to each of said first to third thermal heads.

18. The color thermal printer according to claim 17, wherein each of said first to third thermal heads comprises:

a base plate;

a plurality of heating elements formed on said base plate, each of said plurality of heating elements having a resistance layer and a pair of electrodes connected to said resistance layer; and

a partial glazed glass layer formed between said base plate and each of said plurality of heating elements, said partial glazed glass layer having a semi-cylindrical shape, and having a thickness enough for restraining heat energy therein an appropriate time after the heat energy is radiated from said resistance layer, thereby reducing temperature decay of said plurality of heating elements after a driving time of said first to third thermal heads.

19. The color thermal printer according to claim 18, wherein the first thermosensitive coloring layer is a yellow thermosensitive coloring layer, the second thermosensitive coloring layer is a magenta thermosensitive coloring layer, and the third thermosensitive coloring layer is a cyan thermosensitive coloring layer.

20. The color thermal printer according to claim 19, wherein the yellow thermosensitive coloring layer is optically fixed by ultraviolet rays of substantially 420 nm, and the magenta thermosensitive coloring layer is optically fixed by ultraviolet rays of substantially 365 nm.

21. The color thermal printer according to claim 20, wherein each of said first to third thermal heads is supplied with a bias pulse for heating a respective thermosensitive coloring layer to a temperature just near to a coloring temperature and image pulses corresponding in number to a coloring density, for thermally recording one pixel.

22. A color thermal printing method for printing a multi-color image comprising the steps of:

passing a color thermal recording medium once through a transport path along which first to third thermal heads and first and second light sources are arranged, the color thermal recording medium having first to third thermosensitive coloring layers each developing a different color,

the first to third thermosensitive coloring layers being arranged in a predetermined order having the first thermosensitive coloring layer being an uppermost layer and the third thermosensitive coloring layer being a lowermost layer with the second thermosensitive coloring layer being disposed between the first and third thermosensitive coloring layers;

thermally recording the first thermosensitive coloring layer using the first thermal head;

optically fixing the first thermosensitive coloring layer by radiating electromagnetic rays specific to the first thermosensitive coloring layer from the first light source;

thermally recording the second thermosensitive coloring layer using the second thermal head;

optically fixing the second thermosensitive coloring layer by radiating electromagnetic rays specific to the second thermosensitive coloring layer from the second light source;

thermally recording the third thermosensitive coloring layer using the third thermal head; and

driving the first to third thermal heads in time-sharing fashion with respective first through third drive voltages such that respective driving times of the first and second thermal heads for thermally recording the first and second thermosensitive coloring layers overlap and driving times of the second and third thermal heads for thermally recording the second and third thermosensitive coloring layers are shifted from one another so as not to overlap with one another, the first drive voltage being less than the second drive voltage and the second drive voltage being less than the third drive voltage, thereby reducing maximum instantaneous power consumption of said driving step.

23. A color thermal printing method for printing a multi-color image comprising the steps of:

passing a color thermal recording medium once through a transport path along which first to third thermal heads and first and second light sources are arranged, the color thermal recording medium having first to third thermosensitive coloring layers each developing a different color,

the first to third thermosensitive coloring layers being arranged in a predetermined order having the first thermosensitive coloring layer being disposed as an uppermost layer and the third thermosensitive layer being disposed as a lowermost layer with the second thermosensitive layer being disposed between the first and third thermosensitive coloring layers;

thermally recording the first thermosensitive coloring layer using the first thermal head;

optically fixing the first thermosensitive coloring layer by radiating electromagnetic rays specific to the first thermosensitive coloring layer from the first light source;

thermally recording the second thermosensitive coloring layer using the second thermal head;

optically fixing the second thermosensitive coloring layer by radiating electromagnetic rays specific to the second thermosensitive coloring layer from the second light source;

thermally recording the third thermosensitive coloring layer using the third thermal head; and

driving the first to third thermal heads in time-sharing fashion with respective first through third drive voltages such that respective driving times of the first, second and third thermal heads for thermally recording the first, second and third thermosensitive coloring layers are shifted from one another so as not to overlap with one another, the first through third drive voltages being equal, thereby reducing maximum instantaneous power consumption of said driving step.