Printing device and photographic paper

This application is a divisional application of Ser. No. 09/340,157, filed Jun. 28, 1999, now U.S. Pat. No. 6,126,284, which is a divisional application of Ser. No. 08/661,380, filed on Jun. 11, 1996, now U.S. Pat. No. 6,012,800, which is a continuation of Ser. No. 08/134,677, filed Oct. 12, 1993 now U.S. Pat. No. 5,594,480 of Shuji SATO, et al., entitled PRINTING DEVICE AND PHOTOGRAPHIC PAPER.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a printing device for printing a still picture, such as a picture formed by a video camera or a still television picture, using a vaporized dye, and a photographic paper on which printing is made by such printing device.

2. Description of the Related Art

There has hitherto been known a printing device, such as a sublimation printer, in which a sublimation ink ribbon, coated with a sublimable dye, is superposed on the photographic paper, and an electric energy corresponding to the picture information is applied to a thermal head for subliming the dye on the ink ribbon under a heat energy supplied from the thermal head for transcribing the sublimed dye onto the photographic paper.

The sublimation ink ribbon is prepared by dissolving a sublimable dye in e.g. a solution of acetate or polyester and adding a dispersant to the resulting solution to form a colloidal solution in the form of an ink which is mixed with a binder and subsequently coated on a base paper.

The photographic paper usually has a receptor layer of a heat transfer recording material on a photographic base paper. Among the heat transcription recording materials in current use is a dye-like resin, such as polyester or polycarbonate resin, admixed with a lubricant.

The thermal head is a device which translates an electrical energy into a heat energy, that is a device in which the dye is sublimed from the sublimation ink ribbon under the Joule's heat generated on flowing the current through a resistor for transcribing the sublimed dye onto the photographic paper.

When the recording picture is formed on the photographic paper by the above-mentioned sublimation ink ribbon and thermal head, the receptor layer of the photographic paper undergoes the following changes:

That is, when the heat energy is applied from the thermal head, the polyester resin, for example, of the receptor layer undergoes glass transition and softening and thereby turned into the liquid, at the same time that the dye in the sublimation ink ribbon is transferred onto the receptor layer so as to be dissolved or dispersed in the layer to form the recording picture.

With the above-described sublimation printer, in which printing is made on the photographic paper using the sublimation ink ribbon and the thermal head, it is necessary to provide an ink ribbon takeup mechanism for rewinding the ink ribbon and a heat radiating mechanism for the thermal head. On the other hand, the thermal head usually has a heat conversion efficiency of not higher than 10%, thus leading to considerable power consumption. Thus it has been difficult with the conventional sublimation type printer to realize saving in power and reduction in size and costs.

On the other hand, the sublimation ink ribbon can be used only once for each picture and hence is not economically desirable. Besides, the used-up ink ribbon cassette can not be regenerated and hence is to be discarded in a manner of not destroying the earth's environment.

Besides, the printing by such printing device is carried out by stacking dyes of yellow (Y), magenta (M).and cyan (C), so that it becomes necessary to perform three cycles of the complicated and time-consuming operations of feeding the ink ribbon, vertically moving the thermal head and feeding the photographic paper.

The thermal head generally has the line-head structure of thin resistors generated by sputtering being arranged in a line, thus the size of the printing paper cannot be set freely.

Since it is generally desirable to heat the receptor layer on the photographic paper when subliming and transcribing the sublimable dye onto the photographic paper by the thermal head, it has been a conventional practice to increase the thrusting force of the thermal head to raise the tightness of contact between the ink ribbon and the photographic paper and to apply heat to the receptor layer of the photographic paper by the thermal head. It should be noted that, if the force of thrusting the thermal head to the ink ribbon and the photographic paper is increased, the driving force necessary for the movement of the thermal head, rewinding of the ink ribbon and the feed of the photographic paper has to be correspondingly increased. In addition, since the ink ribbon is prepared by coating the dye processed into an ink on the base paper, as described above, the heat reaches the receptor layer via the base paper and the dye layer. Besides, since air layers tend to be produced between the respective layers, the heat to be applied to the receptor layer needs to be set to take account of heat losses produced in each layer, thus lowering the heat efficiency.

On the other hand, the produced picture tends to be lowered in quality if the photographic paper is not whitened at least directly after printing.

OBJECTS AND SUMMARY OF THE INVENTION

In view of the above-described status of the art, it is an object of the present invention to provide a printing device in which saving in power and reduction in size and costs may be realized without employing a thermal head or an ink ribbon. It is another object of the present invention to provide a printing device in which the printing time may be shortened and the printing paper size may be set freely to assure high picture quality of the printed picture.

It is a further object of the present invention to provide a photographic paper a receptor layer of which may be heated efficiently by the printing device to assure high picture quality of the printed picture.

According to the present invention, there is provided a printing device for thermal transcription of a vaporizable dye onto a photographic paper comprising a dye tank for containing a vaporizable dye, an entrance section for liquefying the vaporizable dye contained in the dye tank and transporting the vaporized dye, and a vaporizing section for vaporizing the liquified dye transported by the entrance section, wherein the dye vaporized by the vaporizing section is thermally transcribed onto the photographic paper.

Preferably, the vaporizable dye contained in the dye tank is powdered.

Preferably, the vaporizing section vaporizes the liquefied dye transported by the entrance section by the heat of vaporization generated responsive to a laser light.

Preferably, the laser light employed for generating the heat of vaporization in the vaporizing section is a laser light having equalized radiation intensity distribution.

Preferably, a region from the dye tank to the vaporizing section is maintained at a temperature of 50° C. to 300° C.

Preferably, the entrance section transports the liquefied dye to the vaporizing section by taking advantage of the capillary phenomenon.

Also preferably, the vaporizing section causes the vaporized dye to be deposited on the photographic paper by taking advantage of a diffusion phenomenon with the aid of beads.

According to the present invention, there is also provided a printing device for thermal transcription of a vaporizable dye onto a photographic paper comprising a containing section for containing a vaporizable dye, a supplying section for supplying the vaporizable dye supplied from the containing section, and a vaporizing section for vaporizing the vaporizable dye supplied by the supplying section under the heat of vaporization, wherein the vaporizable dye vaporized by the vaporizing section is thermally transcribed onto the photographic paper.

Preferably, the vaporizable dye contained in the containing section is a particulate vaporizable dye and the vaporizable dye supplied by the supplying section to the vaporizing section is also a particulate vaporizable dye.

Preferably, the vaporizable dye contained in the containing section is the vaporizable dye deposited on spherical-shaped bodies and the vaporizable dye supplied by the supplying section is also a vaporizable dye deposited on spherical-shaped bodies.

Preferably, the supplying section puts any excess amount of the vaporizable dye to circulation.

The supplying section may put any excess amount of the vaporizable dye to circulation with the aid of beads.

Preferably, the supplying section adds heat responsive to the laser light to the vaporizable dye as the heat of vaporization.

Preferably, the laser light employed for generating the heat of vaporization in the vaporizing section is a laser light having equalized radiation intensity distribution.

According to the present invention, there is also provided a photographic paper in which a vaporized vaporizable dye is absorbed on a receptor layer provided as an upper layer of the photographic paper base, wherein a light absorbing layer formed by a light absorbing agent is provided between the photographic paper base and the receptor layer.

Preferably, the light absorbing layer is whitened in color by thermal destruction of the light absorbing agent itself by a light radiating body in a printing device.

Preferably, the light absorbing layer is whitened in color by thermal destruction of a capsule enclosing a whitening agent therein by a light radiating body in a printing device, wherein the capsule is mixed into the light absorbing layer.

As the light absorbing agent, an infrared ray absorber capable of absorbing infrared rays may be employed. Some of the infrared ray absorbers exhibit color extinguishing characteristics.

Typical of the light absorbing agent is a functional near-IR absorption coloring matter manufactured by SHOWA DENKO KK under the trade name of IR 820B which exhibits maximum absorption for the light having a wavelength of 825 nm. If it is allowed to exist along with an ammonium salt of organic boron, such as tetrabutyl ammoniumbutyl triphenyl borate, in a solution, it absorbs the near IR rays, so that its color is extinguished.

Examples of the whitening agents include titanium oxide, zinc oxide and calcium oxide.

The capsules employed for enclosure of the whitening agents may be formed of condensates, such as polyurea or polyurethane, homopolymers such as polyethylene or polyvinyl alcohol or waxes such as paraffins or lipids.

According to the present invention, there is also provided a printing device in which a vaporizable dye is thermally transcribed onto a receptor layer provided as an upper layer of the photographic paper base, comprising a light radiating body for whitening the color of a light absorbing agent of a light absorbing layer provided between the photographic paper base and the receptor layer.

Preferably, the light emitting body radiates a laser light.

Meanwhile, the term “vaporizable dye” used in the present invention means collectively a solidified disperse dye, a liquefied disperse dye, a vaporized disperse dye, a sublimable dye and a disperse dye. Thus the vaporizable dye is defined as a dye having a temperature domain, in a temperature range of from 25° C. up to a decomposition temperature, for which temperature domain the vapor pressure is not less than 0.01 Pascal, on the provision that, if the dye molecules are associated in a gaseous phase at an average association number of

n

, the vapor pressure divided by the average number of association

n

is not less than 0.01 Pascal.

Although a sublimable dye changed from its solid state to a gaseous state may be contemplated as the vaporizable dye, a dye having the state of a liquid between a solid state and a gaseous state is also included within the meaning of the vaporizable dye.

Among a variety of the vaporizable dyes, a yellow dye, having a color index number “C. I. Disperse yellow 201”, manufactured by SUMITOMO KAGAKU KK under the trade name of “ESC-Yellow 155” and a cyan dye having a color index number “C. I. Solvent Blue 63”, manufactured by SUMITOMO KAGAKU KK under the trade name of “ESC-Blue 655” are employed in the printing device of the present invention. As a magenta dye, a tricyanomethine dye manufactured by MITSUBISHI KASEI KK under the trade name of “HSR-2031” is employed.

With the printing device according to the present invention, the dye tank stows the particulate vaporizable dye, and the entrance section liquefies the vaporizable dye and transports the thus liquefied dye to a vaporizing section, which vaporizes the liquefied dye transported by the entrance section under the heat of vaporization supplied by the laser light for transcription of the vaporized dye onto the photographic paper. The heat generating effect of the vaporizing section is improved by the laser light to enable the size of the heat radiating mechanism to be reduced. Printing becomes possible without employing an ink ribbon or a thermal head, as a result of which power saving and reduction in size and costs may be achieved. By preliminary heating within a low heat conducting material and employing the heat corresponding to the intensity of the laser light for vaporization, the heat efficiency may be improved. The degree of freedom in photographic paper size may be increased because no ink ribbon is necessitated. By providing a light absorbing layer in the photographic paper, the operating efficiency is improved. Besides, the printing time may be shortened.

It is also possible to conduct the liquefied vaporizable Y-dye to the vaporizing section by taking advantage of the capillary phenomenon with the aid of beads, or to use beads in the vaporizing section.

Since the receptor layer of the photographic paper may be heated by the laser light, the portions of the photographic paper other than the receptor layer are not affected by heat.

If the laser light has a flat light intensity distribution, the photo-thermal conversion efficiency may be improved.

With the sublimation type printing device according to the present invention, the containing section stows the particulate vaporizable dye, and the entrance section liquefies the particulate vaporizable dye and transports the thus liquefied dye to a vaporizing section, which vaporizes the liquefied dye transported by the entrance section under the heat of vaporization corresponding to the laser light intensity for transcription of the vaporized dye onto the photographic paper. In this manner, printing becomes possible without employing an ink ribbon or a thermal head so that the printing device may be reduced in size and weight. Dye exchange may be facilitated because the containing section stowing the dye therein may be dismounted and exchanged for new ones. Since the heat of vaporization corresponds to the laser light, excess heat or heat radiation is not required to enable the energy saving. Since the dye may be supplied singly, the photographic paper needs to be fed only once so that the printing time may be shortened. Free-size printing becomes possible because there is no limitation as to the photographic paper size imposed by the ink ribbon.

Besides, since the light absorbing layer formed of a light absorbing agent capable of generating heat by efficiently absorbing the light is provided between the receptor layer and the photographic paper base, the receptor layer may be heated directly to assure a high quality of the printed picture.

In addition, since a light radiating body interposed between the receptor layer and the photographic paper base of the photographic paper whitens the color of the light absorbing agent of the light absorbing layer to assure the high quality of the printed picture.

Consequently, if printing is made on the above-mentioned photographic paper by the above-mentioned printing device, the printing efficiency may be improved and the thrusting force between the dye and the receptor layer may be reduced, while resistance to abrasion may be improved. The picture quality may be improved because the light absorbing agent may be whitened in color.

If the laser light radiated by a laser block as the above-mentioned light radiating body may be of equalized light intensity distribution, it becomes possible to equalize the heat conversion occurring at the light absorbing layer of the photographic paper.

The above and other objects and advantages of the present invention will become apparent from the following description of the preferred embodiments and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1

is a perspective view showing essential portions of a first embodiment.

FIG. 2

is a cross-sectional view showing essential portions of the first embodiment.

FIG. 3

is a perspective view showing essential portions of a vaporizable portion of the first embodiment.

FIG. 4

is a cross-sectional view showing essential portions of a first embodiment employing beads in the vaporizable portion.

FIG. 5

is a back side view showing essential portions of the first embodiment.

FIG. 6

is an illustrative view showing essential portions of the first embodiment.

FIG. 7

is a perspective view showing a typical printing mechanism for the first embodiment.

FIG. 8

is a perspective view showing essential portions of a second embodiment.

FIG. 9

is a perspective view showing a typical printing mechanism for the second embodiment.

FIG. 10

is a back side view showing a laser block provided for the printing mechanism shown in FIG.

9

.

FIG. 11

shows an arrangement of an optical system for equalizing the distribution of the laser light intensity.

FIG. 12A

is a graph showing the distribution of the laser light intensity in case of not employing the optical system shown in FIG.

11

.

FIG. 12B

is a graph showing the distribution of the laser light intensity in case of employing the optical system shown in FIG.

11

.

FIG. 13

is a perspective view showing essential parts of a third embodiment.

FIG. 14

is a perspective view showing the construction of a dye pack playing the role of a container for the third embodiment.

FIG. 15

is a cross-sectional view showing a connecting portion between a dye feed pre-stage and the dye pack playing the role of a container for the third embodiment.

FIG. 16

is a perspective view showing the dye supply pre-stage of the embodiment.

FIG. 17

is a perspective view showing an inner structure of a feed supply post-stage and the feed supply pre-stage for the third embodiment.

FIG. 18

is a schematic perspective view showing essential portions of a laser block according to the third embodiment.

FIG. 19

is a schematic perspective view showing a fourth embodiment.

FIG. 20

is a reverse side view showing a laser block for the second embodiment.

FIG. 21

is a perspective view showing a modified inner structure of a dye supply pre-stage.

FIG. 22

is a perspective view showing a fifth embodiment.

FIG. 23

is a perspective view showing a sixth embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, preferred embodiments of the printing device and the photographic paper according to the present invention will be explained in detail.

In the first embodiment of the present invention, concerning a printing device, a vaporizable dye is employed as a dye.

The vaporizable dye collectively means a solidified disperse dyes, liquified disperse dyes, vaporized disperse dyes, sublimable dyes and disperse dyes, in which a temperature range with a vapor pressure of not lower than 0.01 pascal exists in a temperature range from 25° C. to the dye decomposition temperature. If the dye molecules are associated in the gaseous phase with one another with a mean number of association of

n

, the vapor pressure divided by the mean number of association is to be not less than 0.01 Pascal.

In the present first embodiment, among the above-mentioned vaporized dyes, a vaporized dye manufactured by SUMITOMO KAGAKU KK under a trade name of “ESC-Yellow 155” having a color index number of “C. I. Disperse Yellow 201” is employed as a yellow dye, referred to herein as Y.

As a C dye, a dye manufactured by SUMITOMO KAGAKU KK under the trade name of “ESC-Blue 655”, having a color index number of “C. I. Solvent Blue 63” is employed.

As an M dye, a tricyanomethine dye of the following chemical formula

manufactured by MITSUBISHI KASEI KK under the trade name of “HSR-2031” is employed.

With the first embodiment, the above-mentioned vaporizable dyes Y, C and M are ultimately vaporized and thermally transcribed onto the photographic paper. Therefore, a printer of the first embodiment is referred to hereinafter as a sublimation type printer.

The sublimation type printer of the first embodiment, main portions of which are shown schematically in

FIG. 1

, includes a main body

10

, formed of special high melting plastics, such as polyimide, having low heat conductivity and devoid of heat moldability, dye tanks

11

,

12

and

13

containing the above-mentioned vaporizable Y, M and C dyes in a powdery state, entrance sections

14

,

15

and

16

for dissolving the powdery dyes Y, M and C contained in the dye tanks

11

to

13

to the melting points thereof for transporting the dissolved liquified dyes, and vaporizing sections

17

,

18

and

19

for vaporizing the vaporizable dyes, dissolved and liquified by these entrance sections

14

to

16

, under the heat of vaporization supplied by a laser light beam. The vaporized dyes are deposited on a photographic paper

21

via vaporization openings, not shown, in the bottom parts of recesses or sinks

20

for dyes for each of the vaporizing sections

17

to

19

. These vaporizing sections

17

to

19

are irradiated with laser beams from laser emitting sections for dyes Y, M and C, not shown, as shown by arrows

35

,

36

and

37

, respectively. A transparent section

22

, formed of a glass material with high transmittance to permit a laser light to be transmitted therethrough without losses, is also irradiated with another laser light beam, as shown by an arrow

38

, from a laser radiating section, not shown.

FIG. 2

shows a detailed construction of a sublimation type printer according to the present first embodiment.

In

FIG. 2

, which is a sectional view showing essential portions shown in

FIG. 1

, a laser radiating portion

34

and vaporization openings

23

, not shown in

FIG. 1

, are shown. Meanwhile, since the dye tanks

11

to

13

, entrance sections

14

to

16

and the vaporizing sections

17

to

19

are each of an identical construction, only the dye tank

11

for dye Y, entrance section

14

and the vaporizing section

17

are explained herein for brevity.

The entrance section

14

and the vaporizing section

17

are associated with a first heating member

31

designed for not imparting the heat directly to the photographic paper

21

. The first heating member

31

has its one end

31

a

bent substantially vertically upwards and introduced into the dye tank

11

. The first heating member

31

has its other end

31

b

extended up to a terminal end of the vaporizing section

17

.

The vaporizable dye Y, dissolved and liquified by being heated by the end

31

a

of the first heating member

31

, referred to herein as the liquefied vaporizable dye

32

, is transported by the entrance section

14

up to the entrance section

14

. The entrance section

14

is associated with the first heating member

31

, as mentioned above. This first heating member

31

is formed e.g. of carbon or silicon compounds and capable of radiating the heat of 50° C. to 300° C. on current conduction therethrough to liquefy the vaporizable dye and to maintain the latter in the liquefied and heated state. Besides, the first heating member

31

is of a capillary construction having superficial grooves and is adapted for transporting the liquefied vaporizable dye

32

up to the vaporizing section

17

.

That is, the first heating member

31

transports the vaporizable dye

32

, liquefied under the heat e.g. of 50° C. to 300° C., as far as the vaporizing section

17

, while keeping the dye warm enough not to be solidified or thickened.

The vaporizing section

17

includes a first heating member similar to that provided in the entrance section

14

. The first heating member

31

of the vaporizing section

17

has a plurality of dye sink recesses

20

for stowing the liquefied vaporizable dye. The bottom of each dye sink recess

20

has a large number of vaporizing openings

23

which are fine through-holes each being of a diameter of several microns.

The vaporizing section

17

is provided with a second heating member, not shown, in addition to the first heating member

31

. The second heating member is formed as a layer of a semi-transparent light absorbing agent coated on the surface of the first heating member

31

and each of the dye sink recesses

20

. The second heating member is occasionally referred to herein as a light absorbing layer.

The light absorbing layer efficiently translates the laser light indicated by arrow

35

from laser emitting section

34

into heat. That is, the liquefied vaporizable dye

32

, transported by the entrance section

14

as far as the vaporizing section

17

, is heated up to the vaporizing temperature by the light absorbing layer adapted for efficiently translating the laser light indicated by arrow

35

from laser radiating section

34

into heat. The vaporized dye is transferred onto the receptor layer

21

a

of the photographic paper

21

via the vaporizing openings

23

formed in the bottom of the dye sink recesses

20

.

The concrete construction of the vaporizing section

17

is shown in FIG.

3

.

In this figure, the semi-transparent light absorbing agent, as the above-mentioned second heating member, is coated on the first heating member

31

and on the surface of the bottom of the dye sink recesses

20

.

The liquefied vaporizable dye

32

, shown in

FIG. 2

, transported as far as the vaporizing section

17

by the first heating member

31

having a trenched or grooved structure, is stowed in the dye sink recesses

20

. At this time, the laser light is radiated from the laser radiating section

34

shown in

FIG. 2

onto the dye sink recesses

20

so that the laser light is efficiently translated into heat by the light absorbing layer of the light absorbing agent for vaporizing the liquefied vaporizable dye

32

. The vaporized dye is absorbed by diffusion into the fine vaporizing openings

23

each of a diameter not larger than several microns, formed in the bottom of the dye sink recesses

20

. Since the vaporizing openings

23

are formed so as to be passed through a protective layer

33

so that the vaporized dye is transcribed by diffusion onto the receptor layer

21

a

of the photographic paper

21

shown in FIG.

2

.

Besides, part of the laser light is transmitted through the semi-transparent light-absorbing layer as far as the photographic paper

21

. Part of the light which has reached the photographic paper

21

is used for heating the receptor layer

21

a

to aid in deposition of the vaporizable dye vaporized by the vaporizing section

17

.

The operation of the sublimation type printer according to the above-described first embodiment is hereinafter summarized by referring to

FIGS. 1

to

3

.

With the sublimation type printer of the first embodiment, the vaporizable dye contained within the dye tank

11

is liquefied by being heated by the first heating member

31

of the entrance section

14

up to its melting point. The liquefied vaporizable dye

32

is transported to the vaporizing section

17

by the capillary phenomenon of the entrance section

14

. The entrance section

14

heats the liquefied vaporizable dye

32

by its first heating member

31

to keep its temperature. In addition to the first heating member

31

, which is the same as that provided in the entrance section

14

, a semi-transparent light absorbing layer as the second heating member is provided in the vaporizing section

17

for translating the laser light into heat. The vaporized dye is transferred onto the receptor layer

21

a

of the photographic paper

21

by a phenomenon of diffusion brought about by the vaporizing openings

23

in the bottom of each of the dye sink recesses

20

of the vaporizing section

17

.

The vaporizing section

17

of the sublimation type printer according to the first embodiment may also be designed for transcribing the vaporized dye onto the receptor layer

21

a

of the photographic paper

21

by the diffusion phenomenon brought about by beads, as shown in FIG.

4

.

In

FIG. 4

, the dye tank for the dye Y, as an essential portion, is shown in cross-section.

In this figure, the first heating member

43

has its one end

43

a

introduced into a dye supply opening

42

formed in the lower end of the dye tank

41

. This one end

43

a

of the first heating member

43

melts and liquefies the vaporizable dye. The liquefied vaporizable dye is supplied to the entrance section

44

. In the entrance section

44

, a number of beads

45

are arrayed along the first heating member

43

. Each bead

45

has its upper part bonded to the first heating member

43

with an adhesive and its lower end covered by a protective layer

46

. Similarly, a number of beads

45

are bonded to the first heating member

43

and to a second heating member

48

. The lower part of the beads

45

of the vaporizing section

47

are not covered. The first heating member

43

and the second heating member

48

are bonded to a base

49

.

The base

49

is transparent or otherwise formed with a through-hole in a light transmitting portion thereof for transmitting the light. Besides, it needs to be of as thin a structure as possible. To this end, a reinforcement

50

is provided on the top of the base

49

.

The adhesive employed for bonding the beads

45

, first heating member

43

and the second heating member

48

is heat resistant and transparent.

The protective layer

46

is employed for preventing intrusion of impurities or dust and dirt, so that it is formed of a material which is resistant to heat and abrasion and which is low in heat conductivity. The beads

45

are also heat-resistant and are formed of glass or a heat-resistant synthetic material.

As for the vaporizing section

47

for depositing the vaporized dye onto the photographic paper

21

by relying upon the capillary phenomenon brought about by the beads

45

, the beads

45

are arrayed along the first heating member

43

and the second heating member

48

, so that the arraying area for the beads

45

is extended as shown in

FIG. 5

which is a back side view showing the vaporizing section

47

and the entrance section

44

.

The second heating member

48

, employed in the vaporizing section

47

along with the first heating member

43

, is formed of a light absorbing material.

In the vaporizing section

47

, the second heating member

48

is surrounded in its entirety by the first heating member

43

, as shown in

FIG. 6

, which is a view similar to

FIG. 5

except that the beads

45

are not shown.

The operation of the vaporizing section

47

, employing the beads

45

, is hereinafter explained by referring to

FIGS. 4

to

6

.

The vaporizable dye contained in the dye tank

41

is heated to e.g. 50° C. to 300° C. by the first heating member

43

so as to be turned into the liquefied vaporizable dye which is then permeated through voids defined between beads

45

kept at the above temperature by the first heating member

43

. The liquefied vaporizable dye is then guided under the capillary phenomenon brought about by beads

45

to reach the vaporizing section

47

.

The liquefied vaporizable dye which has reached the vaporizing section

47

is vaporized by being heated by the second heating member

48

adapted for efficiently generating the heat by the laser light radiated from a laser generating section

51

. The dye thus vaporized is passed through voids defined by adjacent beads

45

by diffusion so as to be transcribed onto the receptor layer

21

a

of the photographic paper

21

via the lower ends of the beads

45

not covered by the protective layer

46

.

As a modification of the above-described embodiment in which the beads

45

are employed in the vaporizing section

47

, carbon compounds or light absorbing materials may be contained in or otherwise coated on the surface of the beads so that the beads

45

may simultaneously be employed as the light absorbing material for the second heating member

48

.

With the use of the beads

45

in the vaporizing section

47

, the vaporizing openings are of uniform size to assure a constant amount of vaporization of the vaporizable dye. The light absorbing agent may be coated on or contained in the beads

45

for simplifying the construction. The capillary phenomenon may be easily brought about with a material that cannot be etched. Gradation control may be facilitated by the constant amount of vaporization. Besides, the bead size may be suitably chosen for controlling the air quantity and adjusting the amount of the heat storage. The heat efficiency may be improved by combining the reinforcement with base

49

. Intrusion of dust and dirt or impurities may be inhibited by coating an area other than the vaporizing openings with the protective layer

46

. The beads may be used simultaneously as the wear-resistant layer in contact with the photographic paper

21

to simplify the construction.

An illustrative example of a printing mechanism employing the sublimation type printing device according to the above-described first embodiment is explained by referring to FIG.

7

.

The printing mechanism includes vaporizing units

51

,

52

each consisting in a laser emitting unit built into a sublimation type printer of the first embodiment the essential part of which is shown in FIG.

1

. The two vaporizing units

51

,

52

are of identical construction comprising dye layers

11

,

12

and

13

, entrance sections

14

,

15

and

16

, vaporizing sections

17

,

18

and

19

, four laser radiating sections and a transparent section

22

.

These vaporizing units

51

,

52

are connected to signal lines

53

,

54

and are moved by a vaporizing unit feed shaft

55

and a vaporizing unit supporting shaft

56

in the vaporizing unit feed direction indicated by arrow L.

The photographic paper

21

is fed by a photographic paper driving roll

57

in the paper feed direction indicated by arrow N. The vaporizing units

51

,

52

and the photographic paper

21

are pressed into tight contact with each other by a vaporizing unit supporting roll

58

.

The photographic paper

21

is introduced into a space between the vaporizing units

51

,

52

and the vaporizing unit supporting roll

58

. With the printing mechanism shown in

FIG. 7

, the two vaporizing units

51

,

52

are provided for printing in two sections, with the vaporizing unit being fed in one line. The vaporizable dyes Y, M and C are simultaneously heated and melted by the heating members within the vaporizing units

51

,

52

so as to be turned into liquefied vaporizable dyes.

The vaporizable dye liquefied in the vaporizing units

51

,

52

is heated by the laser light beams associated with picture signals from the Y, M and C laser radiating units so as to be turned into the vaporized dye which is transcribed onto the receptor layer

21

a

of the photographic paper

21

.

After completion of one-line printing, the photographic paper

21

is fed by one-line length by a photographic paper driving roll

57

. Printing is started sequentially for each color and performed in a similar manner after the third dot.

A second embodiment concerning a printing device according to the present invention is hereinafter explained by referring to FIG.

8

.

Each dye employed in the present second embodiment is similar to the sublimable dye employed in the sublimation type printer according to the first embodiment. Since the vaporizable dyes Y, C and M of the present second embodiment are also ultimately vaporized and thermally transcribed onto the photographic paper, the present device is referred to herein as a sublimation type printer according to the second embodiment.

The sublimation type printer according to the second embodiment, essential parts of which are shown schematically in

FIG. 8

, includes dye tanks

61

,

62

and

63

containing powdered vaporizable dyes Y, M and C, entrance sections

64

,

65

and

66

for liquefying the vaporizable dyes supplied from the vaporizing sections

61

to

63

and transporting the liquefied dyes and vaporizing sections

67

,

68

and

69

for vaporizing the vaporizable dyes liquefied by these entrance sections

64

to

66

by the vaporizing heat supplied by the laser light from laser light emitting means, not shown. The vaporizable dye is transcribed onto the photographic paper

21

via the vaporizing openings formed in the vaporizing sections

67

to

69

. It is noted that a plurality of each of the vaporizing sections

67

to

69

are provided along each of the entrance sections

64

to

66

. For example, a number of the vaporizing sections

67

corresponding to the number of dots of a picture are provided along the line direction of the photographic paper shown by arrow L in FIG.

8

. The same is true of the vaporizing sections

68

and

69

.

The operation of the sublimation type printer according to the second embodiment is explained in connection with the dye tank

61

, entrance section

64

and the vaporizing sections

67

shown in FIG.

8

.

A first heating member

71

at the entrance section

64

heats the vaporizable dye in the dye tank

61

so that the vaporizable dye is turned into a liquefied vaporizable dye. The entrance section

64

transports the liquefied vaporizable dye up to the vaporizing sections

67

under a capillary phenomenon as in the case of the sublimation type printer of the previously explained first embodiment.

The liquefied vaporizable dye from the dye tank

61

is transported by the entrance section

64

onto the plural vaporizing sections

67

which are sequentially irradiated with the laser light radiated by laser radiating means, not shown. That is, the first heating member

71

of the entrance section

64

liquefies the vaporizable dye contained in the dye tank

61

at its one end and transports the liquefied vaporizable dye as far as the vaporizing sections

67

by its capillary structure provided by the beads or flutes as it maintains the temperature of 50° C. to 300° C. of the dye to prevent its solidification.

The vaporizing sections

67

are also provided with the first heating member

71

similar to that provided for the entrance section

64

. Each vaporizing section

67

is provided with a plurality of fine vaporizing openings each being of a diameter of several microns. Besides the first heating member

71

, a second heating member

72

is also provided for the vaporizing sections

67

. The second heating member is a light absorbing layer formed by coating a semi-transparent light absorbing agent on the first heating member

71

and the vaporizing openings. The second heating member efficiently translates the laser light from a laser radiating section, not shown, into heat, so that the vaporizable dye introduced into the vaporizing sections

67

is vaporized so as to be transcribed onto the receptor layer of the photographic paper via the vaporizing openings formed in the vaporizing sections

67

. The same construction is employed for the dye tanks

62

,

63

, entrance sections

65

,

66

and the vaporizing sections

68

,

69

.

Besides, since the light absorbing layer is semi-transparent, part of the light which has reached the photographic paper

21

is used for heating its receptor layer

21

a

to aid in deposition of the vaporizable dye vaporized by the vaporizing sections

67

.

An illustrative example of a printing mechanism employing the sublimation type printer according to the second embodiment is hereinafter explained by referring to FIG.

9

.

This printing mechanism comprises a sublimation type printer of the second embodiment, the essential portions of which are shown schematically in

FIG. 8

, and a pair of movable laser blocks

82

,

83

of identical construction for radiating the laser light on the laser block

81

for printing. The sublimation type printer is secured in position as a head block.

Each of the laser blocks

82

,

83

, the reverse side of which is shown in

FIG. 10

, has a laser light outgoing opening

89

a

for Y printing, a laser light outgoing opening

89

b

for M printing, a laser light outgoing opening

89

c

for C printing and a laser light outgoing opening

89

d

for the photographic paper. These laser blocks

82

,

83

are connected to a signal line

84

for laser light and is moved by a laser block feed shaft

85

and a laser block supporting shaft

86

in the line direction as indicated by arrow L. At this time, the laser light outgoing opening

89

a

for Y printing, the laser light outgoing opening

89

b

for M printing and the laser light outgoing opening

89

c

for C printing are positioned directly above the vaporizing sections

67

,

68

and

69

of the head block

81

, respectively.

The photographic paper

21

is fed by paper driving rolls

87

in the paper feed direction indicated by arrow N. The photographic paper

21

is pressed by the paper supporting roll

88

into intimate contact with the head block

81

.

The photographic paper

21

is inserted into a space between the head block

81

and the supporting roll

88

. The vaporizing sections

67

,

68

and

69

are arrayed in alignment with the printing direction indicated by arrow N, with the number of each of the vaporizing sections

67

to

69

along the line direction indicated by arrow L being the same as the number of pixels. The laser light radiating openings in the laser blocks

82

,

83

are set so as to be in register with the vaporizing sections

67

,

68

and

69

of the head block

81

in the paper feed direction or printing direction and arrayed at a rate of the number of the openings to the number of the vaporizing sections

67

to

69

of the head block

81

in the line direction of 1:1 or 1:1/n. If the laser light radiating openings are arranged at a number rate of 1:1 with respect to the vaporizing sections in the head block

81

, the laser radiating openings may be provided in the laser block

81

. Even if the laser light radiating openings are arranged at a number rate of 1:n with respect to vaporizing sections in the head block

81

, the laser radiating openings may be provided in the laser bloc

81

at a number rate of 1/n.

The vaporizable dyes Y, M and C are heated simultaneously by the first heating member within the head block

81

so as to be turned into the liquefied vaporizable dye.

The vaporizable dyes, liquefied by the vaporizing sections

67

,

68

and

69

within the head block

81

, are additively heated by the laser light beams corresponding to the picture signals from the laser blocks

82

,

83

so as to be transcribed onto the receptor layer

21

a

of the photographic paper

21

via the vaporizing openings which provide for dye diffusion. If the laser radiating openings are provided at the number rate of 1/n with respect to the vaporizing sections, the laser blocks

82

,

83

are moved in the line direction indicated by arrow N for completing the printing for one line. The same operation is performed for each of the dyes M and C. The printing for three lines at the start and end of printing is made sequentially and that for the remaining lines is performed simultaneously for the Y, M and C dyes. On completion of printing for one line, the photographic paper

21

is fed by one line by the photographic paper driving roll

87

.

Thus, with the present sublimation type printer according to the present second embodiment, the head block

81

, provided with a plurality of each of the vaporizing sections

67

to

69

, is fixed, while the laser blocks

82

,

83

, having the laser radiating openings thereof aligned with the vaporizing sections

67

to

69

, are moved and the vaporizable dyes, liquefied by the laser light beams @@Corresponding to the picture signals, are additively heated and vaporized for transcription on the photographic paper.

Meanwhile, each vaporizing section of the sublimation type printer according to the second embodiment may also be arranged in accordance with the principle of the capillary phenomenon brought about by beads.

It should be noted that, if a laser light is radiated on the vaporizing sections of the sublimation type printer according to the first or second embodiment after being equalized in intensity in the laser generating section and in the laser blocks over its range of distribution, heat transformation in the light absorbing layer may be equalized and, besides, the energy transformation efficiency may be maximized.

If a semiconductor laser having a light distribution in which the energy density becomes higher towards its mid portion is radiated onto a light absorbing layer is provided in close proximity thereto, a non-uniform thermal energy having only poor efficiency as the energy used for transcribing the dye is produced. Besides, since the energy density is high at the mid region, the receptor layer of the photographic paper onto which the dye is transferred tends to be dissolved or even scorched under the high heat. Also, in view of the angle of light diffusion, the distance between the light source and the an object receiving the light tends to be limited. In addition, because of the non-uniform light distribution, the density of transcription tends to be thicker and thinner towards the mid region and towards the rim portion of the photographic paper, respectively.

It may be contemplated to expand the light distribution of the laser light from the laser light source by a diffusion plate or a concave lens for providing a uniform light distribution on the irradiated surface. That is, it suffices to diminish the degree of concentration towards the mid region in the above-described energy distribution to relax the light concentration to provide a flat light distribution.

FIG. 11

shows an optical system for generating a laser light having an equalized range of distribution of laser light intensity.

Referring to

FIG. 11

, showing such optical system, a laser light radiated from a semiconductor laser

91

is collimated by a collimator lens

92

which is converted into diffused light by e.g. a flat plate micro-lens

93

of a fine micro-lens array construction. The diffused light is then caused to fall on a convex lens

94

which condenses the diffused light to radiate a light having a uniform light intensity distribution onto a light absorbing layer. In this manner, the light distribution similar to a Gaussian distribution, as shown in

FIG. 12A

, is converted into a trapezoidal light distribution as shown in FIG.

12

B.

Therefore, if the distribution of irradiation of the laser light, employed for generating the heat of vaporization at a vaporizing section, is equalized by the optical system shown in

FIG. 11

, the light energy may be converted into a heat energy at a high efficiency. Besides, the use of the above-described optical system leads to a uniform transcription density and coloration with high resolution. The distance between the light source and the irradiated member may be set freely. Besides, a suitable size of coloration may be achieved depending on the manner of designing of the optical system and the semiconductor laser power.

A third embodiment of the present invention concerning the printing device is hereinafter explained by referring to FIG.

13

.

In the present third embodiment, a particulate vaporizable dye, consisting in a mixture of the vaporizable dyes Y, M and C as used in the sublimation type printer of the first or second embodiment and a dispersant compatible with the vaporizable dyes, such as a volatile binder, is employed and vaporized so as to be transcribed under heat onto the photographic paper. For this reason, the third embodiment is referred to herein as a sublimation type printer according to the third embodiment.

The sublimation type printer according to the third embodiment, shown schematically in

FIG. 13

, comprises a dye pack

110

having separate tanks for the particulate Y, M and C dyes, a dye supply pre-stage section

120

for shifting the particulate vaporizable dyes from the dye pack

110

in one predetermined direction, a dye supply post-stage section

140

for receiving the particulate vaporizable dye from the pre-stage section

120

, a vaporizing section, not shown, for receiving and vaporizing the particulate vaporizable dye supplied from the post-stage section

140

, a laser block

150

for radiating a laser light onto the vaporizing section for generating the heat of vaporization therein, a paper feed roll

102

for feeding a photographic paper

21

in a direction shown by arrow N so that the vaporized dye is transcribed thereon, and a photographic paper tray

103

for storing a roll of the photographic paper

21

.

Referring to

FIG. 14

, the construction of the dye pack

110

is first explained.

The dye pack

110

has three separate tanks, that is a Y-tank

111

, an M-tank

112

and a C-tank

113

, in which the above-mentioned particulate vaporizable dyes Y, M and C are stored, respectively. The dye pack

110

is dismountable for exchange and has a hermetically sealed structure to prevent intrusion of humidity or foreign matter or vaporization of the dyes under the effect of ambient light. However, the dye pack

110

also has a fine pore area

114

to permit air venting.

As the dye pack

110

is secured to the dye supply pre-stage section

120

shown in

FIG. 3

by set screws

104

a

to

104

d

, the particulate vaporizable dyes are fed onto the dye supply pre-stage section

120

via a Y-dye outlet

115

, an M-dye outlet

116

and a C-dye outlet

117

, each in the form of protrusions, provided on the bottom of the pre-stage section