JP2000000986A - Pressure-sensitive thermal recording image printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily print a full-color image having clear colors and to improve color representation by selectively controlling pressurizing or heating in pressure- sensitive thermal recording. SOLUTION: Micro-capsules 27 each being formed from a capsule wall film 27a which is melted by being heated at a temperature not less than a limit temperature and containing a black coloring agent 27b and micro-capsules 24, 25, 26 each being broken when being heated at a predetermined temperature or higher or being pressurized by a pressure force not less than a breaking force are provided on a base material 21 of a sheet 20. An image having clear colors is printed by controlling heating and pressurizing of the sheet 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive thermal recording, that is, a high-resolution printer which performs recording by selectively applying pressure and heat.

[0002]

2. Description of the Related Art Conventionally, as an ink used in a high-resolution printer, there has been known an ink in which a heat-sensitive coloring material is sealed in a fine capsule such as a microcapsule. The microcapsules are formed in a layer by a binder (fixing agent) on a base material such as a recording sheet. When the microcapsules corresponding to a plurality of colors are heated at a specific temperature different for each color, the color material of each color develops a color, and light of a different wavelength range is irradiated for each color, so that the base material of the recording sheet is formed. Be established. Therefore, by selectively heating the microcapsules of a plurality of colors at a specific temperature corresponding to each color and irradiating the entire surface of the recording sheet with light in a wavelength range corresponding to each color, the coloring of the plurality of colors is controlled. That is, by controlling the temperature and the light, a full-color image is printed on the sheet.

[0003]

In the process of recording using such a microcapsule, it is necessary to repeat heating and light irradiation for a plurality of colors in order to develop a color material of a plurality of colors. Therefore, the recording process using the recording sheet provided with the capsule is complicated.

On the other hand, in recent years, in forming a full-color image, if black is formed by, for example, forming three primary colors of cyan, magenta, and yellow, true black is not formed, but reddish or bluish black is formed. Are colored on the recording sheet, and the color of the formed image becomes unclear, and the color reproducibility deteriorates.

SUMMARY OF THE INVENTION An object of the present invention is to improve the color reproducibility of an image by easily printing a clear full-color image by controlling pressure and heat recording, that is, selectively controlling pressure and heating. I do.

[0006]

A first pressure-sensitive thermal recording type image printing apparatus according to the present invention heats a microcapsule composed of a capsule wall film enclosing a coloring material at a predetermined temperature or higher. A capsule coloring means for releasing a color material from the microcapsule by applying a pressure equal to or higher than the breaking pressure; and a different color developing means for producing a color different from the color developed by the coloring material of the microcapsule, wherein the capsule coloring means is provided. A heating unit for heating the microcapsules at a predetermined temperature or higher and below the limit temperature, and a pressurizing unit for pressing the microcapsules at a breaking pressure or higher and below the limit pressure, wherein the different color developing unit is a heating unit. Alternatively, a different color is developed using only one of the pressing means.

Preferably, the different-color developing means causes the heat-sensitive material, which develops a different color when heated at a temperature above the limit temperature, to develop a color by heating at a temperature above the limit temperature by the heating means. Preferably, the heat-sensitive material is a microcapsule having a capsule wall film in which coloring materials of different colors are encapsulated and which is melted by being heated at a temperature higher than the limit temperature.

Preferably, the different-color developing means causes the pressure-sensitive material, which develops a different color when pressed at a pressure equal to or higher than the limit pressure, to develop a color by pressing the pressure-sensitive material at the limit pressure or higher. Preferably, the pressure-sensitive material is a microcapsule formed by a capsule wall film enclosing color materials of different colors and broken by being pressed at a pressure higher than a threshold pressure.

[0009] Preferably, a plurality of microcapsules formed by a plurality of capsule wall films each enclosing a color material which emits a color different from each other are broken by a capsule color forming means to discharge the color material. The image is printed, and the different color developing means develops different colors to sharpen the color of the image. For example, the different color is black.

A second pressure-sensitive thermosensitive recording type image printing apparatus according to the present invention comprises a first microcapsule film formed of a first capsule wall film enclosing a first coloring material for producing a first color. First capsule coloring means for heating the capsule at a first temperature or higher and pressing the capsule at a first burst pressure or higher to release a first coloring material from the first microcapsule; A second microcapsule constituted by a second capsule wall film enclosing a second color material that emits a second color different from the second colorant is heated at a second temperature higher than the first temperature or higher. A second capsule color developing means for releasing the second color material from the second microcapsules by applying a pressure equal to or higher than a second burst pressure lower than the first burst pressure; and a first and second color. For developing a third color different from A first heating means for heating the first microcapsules at a temperature equal to or higher than a first temperature and equal to or lower than a second temperature; and a first microcapsule. And first pressurizing means for pressurizing the second microcapsules at a temperature equal to or higher than a second temperature and equal to or lower than a second temperature. A second heating means for heating below the temperature, and
And second pressurizing means for pressurizing at a pressure equal to or higher than the breaking pressure and equal to or lower than the first breaking pressure, wherein the different-color developing means includes first and second heating means, and first and second pressing means. The third color is developed by using any one of the above.

Preferably, the different-color developing means causes the heat-sensitive material, which develops a third color by being heated at or above the limit temperature, to develop color by being heated at or above the limit temperature by the second heating means. Alternatively, it is preferable that the different-color developing means develops a pressure-sensitive material which develops a third color by being pressed at a pressure equal to or higher than the limit pressure by pressing the pressure-sensitive material at a pressure equal to or higher than the limit pressure with the first pressing means.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a high-resolution color printer for pressure-sensitive thermal recording according to a first embodiment of the present invention. The color printer 10 includes a thermal head 30, platen rollers 41, 42, 43, and spring units 51, 52, 53.

The color printer 10 is a line printer, and performs printing for each line extending in a direction orthogonal to the paper surface. The color printer 10 is covered by a rectangular parallelepiped housing 11 that is long in a line direction (a direction orthogonal to the paper surface). An opening 12 for inserting a recording sheet 20 having microcapsules is opened on the upper surface of the housing 11, and an outlet 13 for discharging the sheet 20 is opened on a side surface of the housing 11. ing. The sheet 20 is transported along a transport path (dashed line) connecting the insertion port 12 and the discharge port 13.

The thermal head 30 is provided inside the housing 11 below the transport path. FIG. 2 shows the thermal head 30 as viewed from the platen rollers 41, 42, 43. Above the thermal head 30, a plurality of heating elements 31 are arranged on a straight line parallel to the line direction. Each of the heating elements 31 is connected to a driver circuit 73 to control the heat generation. Similarly, a plurality of heating elements 32 and 33 are arranged on the upper side of the thermal head 30, and the respective heating elements are controlled by driver circuits 74 and 75.

Referring again to FIG. Each heating element 31, 3
2, 33 can generate heat at mutually different heat generation temperatures,
One line on the sheet 20 is selectively heated.

The platen rollers 41, 42 and 43 are cylindrical rubber rollers, and the heating element 3 is provided above the conveying path.
Are rotatably provided at positions corresponding to 1, 32, 33,
It is installed so that its central axis is parallel to the line direction.

The platen rollers 41, 42, 43 are urged by spring units 51, 52, 53 with predetermined different urging forces. Therefore, the sheet 20 includes the platen rollers 41, 42, 43 and the heating elements 31, 32, 3
3, the pressure is evenly applied line by line at a pressure corresponding to the urging force.

The arrangement of the heating elements 31, 32, and 33 and the platen rollers 41, 42, and 43 are provided, for example, three in correspondence with each color in order to emit each color of cyan, magenta, and yellow.

The board 60 is provided with a control device to be described later. With this control device, each platen roller 41,
The rotation of each of the heating elements 31, 32, 3 is controlled.
The driving of the driver circuits 73, 74, and 75 connected to 3 is controlled. Note that the battery 63 is a color printer 10
, And a voltage is applied to a control device and the like.

The sheet 20 is inserted through the insertion opening 12,
By rotating the platen rollers 41, 42, and 43, the sheet is conveyed along the conveyance path at a predetermined speed. Along with this conveyance, the sheet 20 is selectively heated by the heating elements 31, 32, and 33, and the heating elements 31, 32, and 33 are also heated.
And between the platen rollers 41, 42 and 43. As a result, an image is formed by the selectively heated portion of the sheet 20, and the sheet 20 is discharged from the discharge port 13.

When the sheet 20 is conveyed, the heating temperature of the heating element 32 is higher than the heating temperature of the heating element 31 so that the temperature of the sheet 20 changes from a low temperature to a high temperature in order to enhance the temperature controllability. Heating element 33 from the heating temperature of body 32
Is set to increase the heat generation temperature of Accordingly, the urging force of the platen roller 42 is set smaller than the urging force of the platen roller 41, and the urging force of the platen roller 43 is set smaller than the urging force of the platen roller 42.

Referring to FIG. 2 and FIG.
The control device will be described. FIG. 3 is a block diagram showing the control device 61. The control device 61 is provided on the substrate 60 (see FIG. 1) of the color printer 10 and is controlled by the CPU 70.

An image signal of each color component corresponding to an image to be printed is input to the interface 71 from an external device (not shown). The image signal of each color component is input from the interface 71, the image signal of each color component is subjected to predetermined processing by the CPU 70, and pixel data constituting the signal is temporarily stored in the memory 72.

The pixel data of each color component is read from the memory 72, and a control signal DAC,
DAM and DAY are controlled by the CPU 70 so that each of the heating elements 31,
Driver circuits 73 and 7 for generating heat from 32 and 33
4 and 75 respectively.

The driver circuits 73, 74 and 75 have heating resistors Rc1 to Rc constituting the heating elements 31, 32 and 33, respectively.
n, Rm1 to Rmn and Ry1 to Ryn are connected to each other, and the heat generating resistors Rc1 to Rcn, Rm1 to Rmn, R
Strobe signals StC, StM, StY for controlling the heat generation time of y1 to Ryn are input from the CPU 70 to the driver circuits 73, 74, 75.

Heating resistors Rc1-Rcn, Rm1-Rm
n, Ry1 to Ryn are generated by the strobe signal StC,
It is controlled by driver circuits 73, 74, 75 based on StM, StY and control signals DAC, DAM, DAY.

Each heating resistor Rc1 to Rcn is connected to each heating element 3
1 and is provided for producing cyan. Each of the heating resistors Rc1 to Rcn corresponds to each pixel constituting one line of an image printed on the sheet 20 (see FIG. 1). Similarly, the respective heating resistors Rm1 to Rmn and the respective heating resistors Ry1 to Ryn correspond to the respective heating elements 32 and the respective heating elements 3.
3 are provided for emitting magenta and yellow, respectively, and correspond to each pixel constituting one line of the image. Note that each of the heating resistors Rc1 to Rcn,
Rm1 to Rmn and Ry1 to Ryn have the same resistance value.

The platen motor driver 80 is a CPU 70
, And controls the driving of motors 81, 82, 83 connected to the respective platen rollers 41, 42, 43.
Each of the platen rollers 41, 42, and 43 is a sheet 20 (FIG. 1).
In order to give an appropriate tension to the motors 81, 82, 83 at a predetermined rotation speed, the motors 81, 82, 83 are rotated.

When one line of an image of each color of cyan, magenta, and yellow is printed, that is, when the heat generation of each of the heating resistors Rc1 to Rcn, Rm1 to Rmn, and Ry1 to Ryn ends, the CPU 70 causes the platen roller driver 80 to operate. Driven. Thereby, the platen roller 4
The sheets 20, 42 and 43 are rotated by a predetermined amount, the sheet 20 is conveyed, and the next line of the image is printed. The arrangement of the heating resistors Rc1 to Rcn and the heating resistors Rm1 to Rm1
Three lines are printed at the same time by each of the arrangement of mn and the arrangement of the heating resistors Ry1 to Ryn. The three lines correspond to different lines of the image, which are separated from each other by a predetermined distance.

In the above-described color printer 10, in addition to the three subtractive primary colors of cyan, magenta, and yellow, a color different from these three colors, such as true black, is developed to produce a clear image. Will be described.

FIG. 4 is an example of a longitudinal sectional view of the sheet 20. The sheet 20 has a base material 21 which is a white paper, and a capsule layer 22 is formed on the upper side of the base material 21 with a wax-based binder (fixing agent). The capsule layer 22
Fine capsule wall films 24a, 25a, 26a in which coloring materials 24b, 25b, 26b, 27b are encapsulated as a core agent,
Microcapsules 24, 25 constituted by 27a,
On the upper side of the capsule layer 22, a transparent protective film 23 for preventing a printed image from fading due to ultraviolet rays or oxidation is attached. In FIG. 4, the capsule layer 22 includes microcapsules 24, 25,
Although shown as a single layer of 26 and 27, it may be a multilayer,
The microcapsules 24, 25, 26, and 27 are uniformly mixed in the capsule layer 22.

Referring to FIG. 5, microcapsules 24,
25, 26 and 27 will be described. FIG. 5 is a view showing a cross section of the microcapsules 24, 25, 26, and 27.

The microcapsules 24, 25 and 26 and the microcapsules 27 are formed of different materials and have different characteristics.

The microcapsules 24, 25 and 26 are made of cyan, magenta and yellow coloring materials 24b and 2 respectively.
Capsule wall membranes 24a, 25 enclosing 5b, 26b
a, 26a. Each capsule wall membrane 24a,
25a and 26a are made of a white shape memory resin, which is made of, for example, polynorbornene, trans-1,4-polyisoprene, polyurethane, or the like, and has characteristics of temperature and elastic coefficient shown in FIG. . That is, the elastic coefficient of the resin is low in the rubber region b above the glass transition temperature Tg inherent to the resin, and is high in the glass region a below the temperature Tg. Therefore, the shape memory resin is easily broken when heated to a temperature equal to or higher than the glass transition temperature Tg, and hardly solidified and broken when cooled to a temperature equal to or lower than the temperature Tg.

Each capsule wall film 24a, 25a, 26a
Have different glass transition temperatures by forming the above materials in combination at different composition ratios. The glass transition temperature of each capsule wall film 24a, 25a, 26a is set to, for example, 70 ° C., 110 ° C., and 130 ° C.
That is, each capsule wall film 24a, 25a, 26a is
It is easy to be destroyed.

The capsule wall films 24, 25 and 26 have different thicknesses d4, d5 and d6 (where d4>d5>).
d6). As the film thickness increases, the minimum force required to break the capsule wall films 24a, 25a, 26a, that is, the breaking pressure increases. Accordingly, the breaking pressure of the capsule wall film 25a is smaller than the breaking pressure of the capsule wall film 24a, and the breaking pressure of the capsule wall film 26a is smaller than the breaking pressure of the capsule wall film 25a, depending on the thickness d4, d5, d6.

The microcapsules 27 are a heat-sensitive material,
It is composed of a capsule wall film 27a in which a black color material 27b is enclosed as a core agent. The capsule wall film 27a is made of a resin such as white polyethylene, and this resin melts when heated above a predetermined temperature (hereinafter referred to as a limit temperature) higher than the glass transition temperature (for example, 130 ° C.) of the capsule wall film 26a. Having.

The selection of the microcapsules 24, 25, and 26 and the color development of black will be described with reference to FIGS. FIG. 7 shows capsule wall membranes 24a, 25a, and 26.
It is a figure which shows the relationship of temperature and burst pressure of 27a.

Each capsule wall film 24a, 25a, 26a
Has glass transition temperatures T1, T2, T3 and burst pressures P1, P2, P3. Therefore, capsule wall membrane 2
4a, 25a and 26a are glass transition temperatures T1, T
2. It is easily broken by heating to T3 or more, and accordingly, it is broken by being pressed at a breaking pressure P1, P2, P3 or more. The capsule wall film 27
a has a limit temperature T0, and is melted by being heated to the limit temperature T0 or more.

The temperature at which the sheet 20 is heated is T1 or more and T
2 or less, and the applied burst pressure is P1 or more and P0
When the pressure is equal to or less than the (limit pressure) (region c), only the capsule wall film 24a is broken, and the cyan color material 24b is released from the capsule wall film 24a. That is, the microcapsules 24 are colored, and the sheet 20 is colored cyan.

Similarly, the temperature at which the sheet 20 is heated is T2
When the pressure is not more than T3 and the breaking pressure to be applied is not less than P2 and not more than P1 (region d), the capsule wall film 25a
Is destroyed, and the magenta color material 25b is released. That is, the microcapsules 25 are colored, and the sheet 20 is colored magenta. Temperature is T3 or more T0
When the pressure is equal to or less than P3 and is equal to or more than P3 and equal to or less than P2 (region e), only the capsule wall film 26a is broken and the yellow color material 26b is released. That is, the microcapsules 26 are colored, and the sheet 20 is colored yellow.

The temperature at which the sheet 20 is heated is the limit temperature T
When it is 0 or more (region f), the capsule wall film 27a is melted and the black color material 27b is released.

In the color printer 10 (see FIG. 1), the urging forces of the platen rollers 41, 42 and 43 are set to the burst pressures in the areas c, d and e, respectively.
The heat generation temperatures of 1 and 32 are set to the temperatures in the regions c and d, respectively. The heating temperature of the heating element 33 is set to be switchable between the temperature in the area e and the limit temperature T0. The biasing forces of the platen rollers 41, 42, 43 set below are p1, p
2, p3, and the set heating temperatures of the heating elements 31, 32 are t1, t2. Further, one heat generation temperature of the heating element 33 (the temperature in the region e) is set to t3. And the heating element 3
The capsule wall films 24a, 25a, and 26a are controlled by controlling the heating at the heating temperatures t1, t2, and t3 by the first, second, and third 33 and the pressurization by the platen rollers 41, 42, and 43.
Is selected and destroyed with high precision, and the color material 2 of the color to be colored
4b, 25b, 26b are released. Thus, a full-color image is printed on the sheet 20. Further, by switching the heat generation temperature of the heating element 33 to the limit temperature T0, the capsule wall film 27a is broken, and the black color material 27b is released.
The sheet 20 is colored with true black, and a clear full-color image is printed.

Referring to FIG. 3, FIG. 7 and FIG.
The heat generation control of 32 and 33 will be described. FIG. 8 is a diagram showing signals for controlling the driver circuits 73, 74, and 75.

For example, when forming one line L of an image,
Each pixel D1, D2, D constituting a part of this one line L
It is assumed that the color information 3 and D4 are B (black), Y (yellow), M (magenta), and C (cyan), respectively. Heating resistors Rc1 to Rc constituting the heating elements 31, 32, 33
4, Rm1 to Rm4, Ry1 to Ry4 are each pixel D1,
When forming D2, D3, D4, each pixel D1, D2, D
3, heat is selectively generated on the basis of the color information of D4 (in the figure, a mark indicates a heat-generating element). When an image is formed, each of the pixels D1, D2 is generated by each of the heating resistors Rc1 to Rc4.
After heat is generated to form 2, D3 and D4,
After a lapse of a predetermined time, heat is generated by each of the heating resistors Rm1 to Rm4 to form the pixels D1, D2, D3, and D4.
Ry4 generates heat for forming the pixels D1, D2, D3, and D4.

Heating resistors Rc1, Rm corresponding to pixel D1
1 and Ry1, since the color information of the pixel D1 is B, all the resistors Rc1, Rm1, Ry1 are used to form all the cyan, magenta and yellow colors and to make black color.
Is heated. Heating resistor Rc corresponding to pixel D2
In 2, Rm2, and Ry2, since the color information of the pixel D2 is Y, only the heating resistor Ry2 for generating yellow color is caused to generate heat. Heating resistor R corresponding to pixel D3
In c3, Rm3, and Ry3, since the color information of the pixel D3 is M, the heating resistor Rm3 for producing a magenta color is formed.
Only heat is generated. In the heating resistors Rc4, Rm4, and Ry4 corresponding to the pixel D4, since the color information of the pixel D4 is C, the heating resistor Rc4 for emitting cyan color.
Only heat is generated.

The pixel data DC, DM, and DY of each color component constituting the image signal of one line L are represented by the pixels D1, D2,
Based on the color information of D3 and D4, it is data that sets the color component of the color to be developed to “1”. Pixel data DC, D
When M and DY are “1”, the heating resistors Rc1 to Rc4, Rm1 to Rm4, and Ry1 corresponding to the pixel data are generated.
Only Ry4 is heated by the driver circuits 73, 74, 75.

The driver circuits 73, 74 and 75 have heating resistors Rc1 to Rc4, Rm1 to Rm4 and Ry1 to Ry4.
Strobe signals StC and S for controlling the heat generation time of
tM and StY are input. Strobe signals StC, S
tM and StY are signals controlled by the CPU 70. Each of the strobe signals StC, StM, StY is a pulse signal, and its pulse width, that is, strobe time W
c, Wm, Wy, and Wb are heating resistances Rc1 to Rc4, R
exothermic temperatures t1, t2 of m1 to Rm4, Ry1 to Ry4,
It corresponds to t3 and the limit temperature T0, respectively, and is a time during which the heating resistors Rc1 to Rc4, Rm1 to Rm4, and Ry1 to Ry4 can generate heat.

The driver circuits 73, 74, and 75 supply control signals DA based on the pixel data DC, DM, and DY of each color component together with the strobe signals StC, StM, and StY.
C, DAM, and DAY are input. Control signals DAC, D
AM and DAY are signals controlled by the CPU 70.

When the pixel data DC is "1", the control signal DAC holds the high level (code SdC) for the same time as the strobe time Wc of the strobe signal StC. Similarly, when the pixel data DM is “1”, the control signal DAM keeps the high level (code SdM) for the same time as the strobe time Wm of the strobe signal StM.

The control signal DAY includes three pixel data D
It changes according to C, DM, and DY. When the pixel data DY is “1” and at least one of the pixel data DC and the pixel data DM is “0”, the control signal D
AY holds a high level (reference symbol SdY) for a control time Wy shorter than the strobe time Wb of the strobe signal StY. The control time Wy is a heat generation time corresponding to the above-described heat generation temperature t3.

On the other hand, when the pixel data DY is “1” and the pixel data DC and the pixel data DM are both “1”, the control signal DAY is the strobe signal S
The high level (symbol SdB) is held for the same time as the strobe time Wb of tY. The strobe time Wb is a heat generation time corresponding to the limit temperature T0.

While the strobe signals StC, StM, StY and the control signals DAC, DAM, DAY are both at a high level, the driver circuits 73, 74, 75 cause the heating resistors Rc1 to Rc4, Rm1 to Rm4, Ry1 to Ry4 to generate heat. I'm sullen. That is, in the pixel D4, the heating resistance R
Only c4 is heated during the strobe time Wc,
As a result, the heating resistor Rc4 reaches the heating temperature t1, and a cyan color is developed. In the pixel D3, only the heating resistor Rm3 is heated during the strobe time Wm, whereby the heating resistor Rm3 reaches the heating temperature t2, and a magenta color is developed.

In the pixel D2, only the heating resistor Ry2 is caused to generate heat during the control time Wy.
y2 becomes the heat generation temperature t3, and a yellow color is developed.
In the pixel D1, the heating resistors Rc1, Rm1, and Ry1 are heated during the strobe times Wc, Wm, and Wb, respectively, so that the heating resistors Rc1 and Rm1 have the glass transition temperatures T1 and T2, and the heating resistor Ry1 has the limiting temperature T0. become. That is, cyan, magenta, yellow, and black are developed. When the pixel data DC, DM, and DY are all “1”, the CPU 70 controls the control signal Sd.
Only the control signal SdB among C, SdM, SdB, and SdY may be output, and only black may be developed.

As described above, each of the heating elements 31, 32, 33,
That is, each of the heating resistors Rc1 to Rcn, Rm1 to Rmn,
The heat generation of Ry1 to Ryn is controlled. That is, the strobe signals StC, StM, StY and the control signals DAC, DA
Based on M and DAY, each of the heating elements 31, 32, and 33 generates heat at a predetermined temperature. In particular, the heating element 33 can generate heat at two temperatures, a heating temperature t3 and a limit temperature T0.
The temperature can be switched according to the pixel data DC, DM, DY. The heating resistors Rc1 to Rcn, Rm1 to Rmn, R
y1 to Ryn may have different resistance values for each of the heating elements 31, 32, and 33.

In the color printer 10 shown in FIG.
When the above-described heat generation control is performed, a certain line of the sheet 20 is selectively colored cyan between the heat generator 31 and the platen roller 41 based on the cyan pixel data DC. The magenta color is selectively colored between the body 32 and the platen roller 42 based on the magenta pixel data DM.
3, yellow or black is selectively colored based on the pixel data DC, DM, and DY of each color component. Thus, an image is printed on the sheet 20.

According to the first embodiment, by changing the pressure and the temperature, the microcapsules 24,
25 and 26 are easily selected and the capsule wall films 24a,
5a and 26a are destroyed, and coloring materials 24b and 25
b and 26b are released. Thereby, a full-color image is easily formed on the sheet 20. The sheet 20 has microcapsules 27, and the microcapsules 2
4, 25, and 26 (color heat generation temperature t1,
By heating at a temperature different from (t2, t3) (for example, the limit temperature T0), the capsule wall film 27a of the microcapsule 27 is melted, a black color material 27b is released, and the sheet 20 is colored black. .

Normal cyan, magenta, yellow colors 24
By causing all of b, 25b, and 26b to develop color, black is printed on the sheet 20. However, this black color is not true black but a reddish or bluish black color, so that the color of the printed image is unclear and the color reproducibility of the image is degraded.

On the other hand, in the first embodiment, when printing black, cyan, magenta, and yellow color materials 24b,
25b and 26b, and a black color material 27
Since b is colored, a true black color is formed on the sheet 20, a clear image is formed, and the color reproducibility of the image is improved. Heating element 33 for further developing yellow color
Is used to control the heat generation time to produce black color, so that true black color is easily produced without increasing the size of the apparatus.

In the first embodiment, in order to efficiently control (heat and cool) the temperature of the heating element, the heating element 33 for destroying the microcapsules 26 that develop color at the highest temperature (heating temperature t3). Is used to produce black, but other heating elements may be used to produce black. Further, another color may be developed instead of black as a color different from the color materials 24b, 25b, and 26b.

The second embodiment will be described with reference to FIGS. FIG. 9 is a side sectional view showing a high-resolution color printer according to the second embodiment. FIG. 10 is a diagram showing signals for controlling the driver circuit provided in the second embodiment.

The second embodiment differs from the first embodiment in that a heating element 34 for producing black color and a platen roller 44 are provided, and the other points are the same.
Hereinafter, only different points will be described.

The color printer 100 of the second embodiment
The color printer according to the first embodiment includes a heating element 34 for producing black color and a platen roller 44. The heating elements 34 are provided on the upper side of the thermal head, and are arranged in plural on a straight line parallel to a direction (line direction) perpendicular to the paper surface. A platen roller 44 is provided at a position corresponding to the heating element 34 on the upper side of the transport path (dashed line). The platen roller 44 transfers the sheet 20 to the heating element 3.
4 is a cylindrical rubber roller for bringing the roller into close contact with 4, and is installed so that the central axis thereof is parallel to the line direction.

A driver circuit (not shown) is connected to the heating element 34. This driver circuit is similar to the driver circuit connected to the heating elements 31, 32, and 33 in the first embodiment, and is controlled by the CPU 70 (see FIG. 3).

The heating elements 31 and 32 generate heat in the same manner as in the first embodiment. The heating element 33 outputs a strobe signal St.
While both Y and the control signal DAY are at the high level, that is, during the strobe time Wy, heat is generated to cause the yellow color to develop. The heating element 34 keeps the strobe signal StB and the control signal DAB high while both are at a high level.
That is, during the strobe time Wb, heat is generated to generate black color. These strobe times Wy, Wb
Respectively correspond to the heat generation temperatures of the heat generating elements 33 and 34, that is, the heat generation temperature t3 and the limit temperature T0.

The same effects as those of the first embodiment can be obtained in the second embodiment. Furthermore, in the second embodiment, the temperature of the heating element is not easily switched in the same heating element, so that the temperature control of the heating element is easy. The second embodiment has a configuration in which all the cyan, magenta, and yellow colors are formed when black is formed in the same manner as the first embodiment. However, only the black color is formed without forming the cyan, magenta, and yellow colors. It is good also as a structure which makes a color develop.

The third embodiment will be described with reference to FIGS. FIG. 11 is a diagram showing the relationship between the temperature and the burst pressure in the third embodiment. The third embodiment differs from the first and second embodiments in that the microcapsules that emit black color are pressure-sensitive materials, and the other points are the same. Hereinafter, only different points will be described.

The sheet 20 has microcapsules 2 instead of the microcapsules 27 of the first and second embodiments.
7 'is provided, and the microcapsules 27' are a pressure-sensitive material, and are constituted by a capsule wall film 27a 'in which a black color material 27b' is sealed. This capsule wall film 27
a ′ is formed of a resin that is destroyed by being pressed at a pressure equal to or higher than the limit pressure P0. When the pressure applied to the sheet 20 is equal to or higher than the limit pressure P0 (region g), a black color is formed.

In the third embodiment, for example, a plurality of piezoelectric elements are provided corresponding to the pixels in place of the heating element 34 of the color printer 100 shown in FIG. It is pressurized and a black color develops.

According to the third embodiment described above, by forming the heat-sensitive material of the first and second embodiments from a pressure-sensitive material, black color is generated by pressure control. In the third embodiment, the same effects as in the first and second embodiments can be obtained.

The fourth embodiment will be described with reference to FIGS. The fourth embodiment is different from the first embodiment to the third embodiment in that microcapsules 24 ′, 25 ′ and 2 ′ forming the capsule layer 22 of the sheet 20 are formed.
6 ′. In the fourth embodiment, the capsule layer 22
Are the microcapsules 24 ′, 25 ′, 26 ′ and the microcapsules 27 or 3 of the first and second embodiments.
And the microcapsules 27 'of the embodiment. Hereinafter, only different points will be described.

Microcapsules 24 ', 25', 26 '
Color materials 24b ', 25b', and 26b 'have cyan, magenta, and yellow colors, respectively. This color material 2
4b ', 25b' and 26b 'are solid phases at normal temperature (about 25 ° C.), and are a mixture of a colorant and a vehicle for fixing the particles of the colorant. Each color material 24b ',
Each of 25b 'and 26b' has a different melting temperature, and each melting temperature depends on the vehicle to be compounded. The colorant used here is, for example, phthalocyanine blue, rhodamine lake T, benzine yellow G, etc., and the vehicle is, for example, a low melting point thermoplastic resin (EV).
A, polyethylene, polyester, styrene / acrylic copolymer, etc.) and waxes (carnauba, microcrystalline wax, paraffin, montan, etc.).
Hereinafter, a mixture of phthalocyanine blue and a paraffin-based wax as a color material 24b '
A case in which a mixture of rhodamine lake T and carnauba-based wax is used, and a case in which benzine yellow G is mixed with a low-melting thermoplastic polyethylene are used as coloring material 26b '.

FIG. 14 shows color materials 24b ', 25b', and 26.
b ′ temperature and elastic modulus characteristics, and capsule wall film 24
The characteristics of temperature and elastic modulus of a ', 25a', and 26a 'are shown. The elastic coefficient of the coloring material 24b 'tends to decrease with an increase in temperature, and starts to decrease sharply from the temperature T'24 and becomes soft and fluid. That is, the coloring material 24b 'starts melting from the temperature T'24 and becomes liquid at the temperature T24. Similarly, color material 25
b 'and 26b' start melting at temperatures T'25 and T'26, respectively, and become liquid at temperatures T25 and T26, respectively. Color material 2
The melting temperature T24 of 4b 'is lower than the melting temperature T25 of the coloring material 25b', and the melting temperature T25 of the coloring material 25b 'is 26b'.
Is lower than the melting temperature T26. Thus, each color material 24
Melting temperatures T24, T25, T26 of b ', 25b', 26b '
To determine each color material 24b ', 25b', 26b '
Vehicle materials have been formulated.

Microcapsules 24 ', 25', 26 '
The capsule wall films 24a ', 25a', and 26a 'are white and made of, for example, melamine, polyamide, polyimide, titanium dioxide, silica, or the like. These capsule wall films 24a ', 25a', 26a '
Heat resistance higher than 5b 'and 26b' (for example, 250 ° C.
About 500 ° C.), and each capsule wall film 24a ′, 25
a 'and 26a' have different thicknesses d4 ', d5' and d
6 ′. Then, the film thickness d of the capsule wall film 24a '
4 ′ is larger than the film thickness d5 ′ of the capsule wall film 25a ′, and the film thickness d5 of the capsule wall film 25a ′ is
6a 'is larger than the film thickness d6.

The capsule wall films 24a ', 25a', 26
a ′ is independent of the temperature below 250 ° C.
It has a substantially constant modulus of elasticity, and the temperature characteristic of the burst pressure required to cause elastic or plastic fracture substantially follows this characteristic. The breaking pressure of the capsule wall films 24a ', 25a', 26a 'depends on the respective film thicknesses d4', d5 ', d6'. ', 26a' is destructible.

The color materials 24b ', 25b', 2
6b ′ and the capsule wall film 24a ′, 25a ′,
Microcapsule 2 using the burst pressure of 26a '
4 ', 25', and 26 'are selectively colored. That is, the coloring material 24 is selectively heated at a predetermined temperature.
b ′, 25b ′, and 26b ′ are melted, and the capsule wall film 24a ′,
25a 'and 26a' are destroyed and the capsule wall membrane 24 is broken.
a ', 25a', 26a 'melted colorant 24
b ', 25b', 26b 'are selectively released, and the microcapsules 24', 25 ', 26' are selectively colored. The following microcapsules 24 ', 25', 2
The selective coloring of 6 'will be described.

FIG. 15 shows microcapsules 24 ', 2
The temperature and burst pressure characteristics of 5 'and 26' are shown. The temperature / burst pressure characteristics of the microcapsules 24 ′, 25 ′, and 26 ′ include the temperature / elastic coefficient characteristics and the particle size of the coloring materials 24 b ′, 25 b ′, and 26 b ′, and the capsule wall membranes 24 a ′
This is a characteristic based on the temperature / elastic coefficient characteristics of a ′ and 26a ′ and the particle size of the microcapsules 24 ′, 25 ′ and 26 ′.

In a region on the upper right side of the characteristic curve of the microcapsules 24 ', the coloring material 24b' can be melted, the capsule wall film 24a 'can be broken, and the microcapsules 24' can color. Similarly, in the region on the upper right side of the characteristic curves of the microcapsules 25 'and 26', the coloring materials 25b 'and 26b' can be melted and the capsule wall films 25a 'and 26' can be melted.
a ′ is destructible and each microcapsule 25 ′, 2 ′
6 'can be colored.

In the hatched area h on the upper right side of the characteristic curve of the microcapsule 24 'and on the lower left side of the characteristic curve of the microcapsule 25', only the microcapsule 24 'can be colored. In the shaded area j on the upper right side of the characteristic curve of the microcapsules 25 'and on the lower left side of the characteristic curves of the microcapsules 24' and 26 ', only the microcapsules 25' can be colored. In the hatched area k on the upper right side of the characteristic curve of the microcapsules 26 'and on the lower left side of the characteristic curve of the microcapsules 25', only the microcapsules 26 'can be colored. As is clear from the above, by controlling the temperature and pressure, the microcapsules 24 ', 2
5 ′ and 26 ′ can be colored. In the shaded area f, the microcapsules 27 shown in FIG. 5 can be colored, and in the shaded area g, the microcapsules 27 'shown in FIG. 12 can be colored.

The above microcapsules 24 ', 25',
The heating elements 34, 35,
36, and the urging forces of the platen rollers 41, 42, 43 are determined. Cyan microcapsules 2
In order to develop the color 4 ', the heating temperature of the heating element 34 is set to the temperature t1 in the hatched area h, and the urging force p1 of the platen roller 41 is set to the breaking pressure p1 in the hatched area h. Further, in order to cause the magenta microcapsules 25 'to develop a color, the heat generation temperature of the heating element 35 is set to the temperature t2 in the hatched area j, and the urging force of the platen roller 42 is set to the breaking pressure p2 in the hatched area j. . Similarly, in order to cause the yellow microcapsules 26 'to develop a color, the heating temperature of the heating element 36 is set to the temperature t3 in the shaded area k, and the urging force p3 of the platen roller 43 is reduced to the breaking pressure p3 in the shaded area k. Determined.

Also in the fourth embodiment, the microcapsules 2 are formed by changing the pressure and the temperature.
4 ', 25', and 26 'can be easily and selectively colored to easily form an image on the sheet 20. In printing black, cyan, magenta, and yellow microcapsules 24 ', 25', and 26 'are colored, and black microcapsules 27 or 27' are colored. A color is formed, a clear image is formed, and the color reproducibility of the image is improved.

[0082]

As described above, according to the present invention, a full-color image with clear colors can be easily printed by controlling the pressure and heat recording, that is, selectively controlling the pressure and the heating, and the color reproducibility of the image can be easily obtained. Is improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a high-resolution color printer for pressure-sensitive thermal recording according to a first embodiment of the present invention.

FIG. 2 is a view of the thermal head as viewed from a platen roller side.

FIG. 3 is a block diagram showing a control device.

FIG. 4 is a diagram illustrating an example of a longitudinal section of a sheet.

FIG. 5 is a sectional view of a microcapsule.

FIG. 6 is a diagram showing characteristics of temperature and elastic modulus of a shape memory resin.

FIG. 7 is a diagram showing a relationship between a glass transition temperature of a capsule wall film and a breaking pressure.

FIG. 8 is a diagram showing control signals for controlling a driver circuit.

FIG. 9 is a side sectional view of a high-resolution color printer for pressure-sensitive thermal recording according to a second embodiment.

FIG. 10 is a diagram illustrating control signals for controlling the driver circuit according to the second embodiment.

FIG. 11 is a diagram illustrating a relationship between a burst pressure and a temperature of a capsule wall film according to a third embodiment.

FIG. 12 is a cross-sectional view of a microcapsule that emits black color according to the third embodiment.

FIG. 13 is a sectional view of a microcapsule according to a fourth embodiment.

FIG. 14 is a diagram illustrating characteristics of temperature and elastic coefficient of a capsule wall film and a coloring material according to a fourth embodiment.

FIG. 15 is a diagram showing the relationship between the temperature and the burst pressure of the microcapsule of the fourth embodiment.

[Explanation of symbols]

 24, 25, 26 Microcapsules 24a, 25a, 26a Capsule wall film 24b, 25b, 26b Color former

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Saito 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd. (72) Inventor Katsuka Suzuki 2-36 Maenocho, Itabashi-ku, Tokyo 9 Asahi Gaku Kogyo Co., Ltd. (72) Inventor Koichi Furusawa 2-36-9 Maenocho, Itabashi-ku, Tokyo Asahi Gaku Kogyo Co., Ltd.

Claims (10)

[Claims] 1. Capsule color development in which a microcapsule composed of a capsule wall film in which a coloring material is enclosed is heated at a predetermined temperature or higher and is pressed at a breaking pressure or higher to release the coloring material from the microcapsule. Means, and a different color developing means for producing a color different from the color developed by the coloring material of the microcapsules, wherein the capsule coloring means heats the microcapsules at a temperature higher than the predetermined temperature and lower than the limit temperature. Heating means, and pressurizing means for pressurizing the microcapsules at a pressure equal to or higher than the breaking pressure and equal to or lower than the limit pressure, wherein the different color developing means uses only one of the heating means or the pressing means. A pressure-sensitive heat-sensitive recording type image printing apparatus, wherein the different colors are developed by applying a pressure. 2. The method according to claim 1, wherein the different-color developing means heats the heat-sensitive material that develops the different color when heated at or above the limit temperature by heating the heat-sensitive material at or above the limit temperature with the heating means. The pressure-sensitive thermosensitive recording type image printing apparatus according to claim 1. 3. The heat-sensitive material is a microcapsule comprising a capsule wall film in which the coloring materials of different colors are sealed and which is melted by being heated at or above the limit temperature. Item 3. A pressure-sensitive thermosensitive recording type image printing apparatus according to Item 2. 4. The pressure-sensitive material, which develops the different color when the different-color developing means is pressed at a pressure equal to or higher than the limit pressure, is colored by pressing the pressure-sensitive material at the limit pressure or higher by the pressing means. The pressure-sensitive thermosensitive recording type image printing apparatus according to claim 1, wherein: 5. The pressure-sensitive material is a microcapsule comprising a capsule wall film enclosing the coloring material of the different color and destroyed by being pressed at a pressure equal to or higher than the threshold pressure. The pressure-sensitive thermosensitive recording type image printing apparatus according to claim 4. 6. The capsule color forming means breaks a plurality of microcapsules constituted by a plurality of capsule wall films each enclosing the color material which emits a color different from each other, and The pressure-sensitive thermosensitive recording type image printing apparatus according to claim 1, wherein the image is printed by emitting the color, and the different color developing means develops the different color to sharpen the color of the image. . 7. The image printing apparatus according to claim 1, wherein the different color is black. 8. A first microcapsule composed of a first capsule wall film enclosing a first color material that emits a first color is heated at a first temperature or higher, and the first microcapsules are heated at a first temperature or higher. A first capsule color developing means for releasing the first color material from the first microcapsules by applying a pressure equal to or higher than the breaking pressure of the first micro capsule; and a second color developing means for developing a second color different from the first color. Of the second capsule wall film in which the color material is encapsulated.
Heating the microcapsules at a second temperature higher than the first temperature and at a second burst pressure lower than the first burst pressure.
A second capsule color developing means for releasing the second color material from the microcapsules, and a different color developing means for developing a third color different from the first and second colors. A first heating means for heating the first microcapsules at a temperature equal to or higher than the first temperature and equal to or lower than the second temperature; and A first pressurizing means for pressurizing at a pressure not lower than the breaking pressure and not higher than the limit pressure,
A second heating means for heating the second microcapsules at a temperature equal to or higher than the second temperature and equal to or lower than the limit temperature; and a means for heating the second microcapsules equal to or higher than the second burst pressure. And second pressurizing means for pressurizing at a pressure equal to or lower than the first burst pressure, wherein the different-color developing means includes the first and second heating means, the first and second heating means.
Wherein the third color is developed using any one of the pressure means. 9. The color development by heating the heat-sensitive material, which develops the third color by heating the above-mentioned different color developing means at or above the limit temperature, at or above the limit temperature by the second heating means. 9. The method according to claim 8, wherein
2. The pressure-sensitive thermosensitive recording type image printing apparatus according to item 1. 10. The pressure-sensitive material that develops the third color when the different-color developing means is pressed at a pressure equal to or higher than the limit pressure is pressed by the first pressing means at a pressure equal to or higher than the limit pressure. 9. The pressure-sensitive thermosensitive recording type image printing apparatus according to claim 8, wherein the color is formed by applying a color.