JPH07256902A - Release image forming method - Google Patents

Abstract

PURPOSE:To obtain a release image forming method in which unevenness of density can be suppressed by controlling a quantity of incident light to an image forming layer on a time series system. CONSTITUTION:In a release image forming method, an image is recorded by scanning a thermal transfer sheet 121, successively supporting at least hot melt ink and a layer to be subjected to transfer, by an optical beam holding image information, the ink softened and melted by the heat of the optical beam is transferred to the layer to be subjected to transfer, and the thermal transfer sheet 121 is released from the layer to be subjected to transfer. Therefore, in a laser current control means 113, an optical beam with an overshoot of a required level imparted to each leading edge is generated. An image is recorded by scanning the thermal transfer sheet 121 by the optical beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image recording by light beam scanning, and more particularly to a peeling image forming method employing a dry developing method.

[0002]

2. Description of the Related Art In recent years, an image has been formed on a recording material by scanning a light beam with an increase in the sensitivity of the recording material. That is, a light beam carrying image information that is deflected in the main scanning direction is made incident on a thermal transfer sheet that is conveyed and moved in a sub scanning direction orthogonal to the main scanning direction, whereby an image forming layer that constitutes the thermal transfer sheet is formed. , Images are recorded in a time-sequential sequential manner.

The light beam carrying image information is generated by an optical modulator which modulates the intensity of the light beam emitted from the light source according to the image information. The output of the light beam is set at the same output level in time series for the same image information. That is, the same image information is modulated with the same output intensity from the rising edge to the falling edge.

The image formed on the image forming layer constituting the thermal transfer sheet is subjected to a peeling step, and the image is transferred and formed on the image receiving layer.

[0005]

A light beam having the above-mentioned output characteristics is made incident on the image forming layer to transfer the image recorded on the image forming layer to the image receiving sheet, and then the thermal transfer sheet is peeled off from the image receiving sheet. In this case, in the peeling step, at the peeling start position, the energy due to the irradiation of the light beam is used as the energy from the low temperature of the base material to the high temperature at which the bonding force between the photothermal conversion layer and the image forming layer decreases. Since it takes a time required for the temperature to rise, the line becomes thin at the recording tip. On the other hand, at the peeling end position, the line does not become thin because the substrate is already at a high temperature.

Therefore, even though it is desired to record the same image information, the shape of the line at the tip of the recording line is different from that at the end of the recording line and is not stable, so that the dot shape becomes unstable, and uneven density occurs. Cause the situation. In addition, due to the specific heat characteristic of the heat-meltable ink transferred to the image receiving sheet, the amount of heat supplied to the ink is insufficient at the peeling start position, so the ink does not melt sufficiently, and therefore the recording line tip is It becomes thin.

The above phenomenon can be dealt with by increasing the output intensity of the light beam in order to increase the amount of heat supplied to the ink. However, if the output intensity of the light beam is increased in accordance with the ink transfer characteristic at the recording line tip, the tailing of the ink will occur at the recording line termination, and the recording line termination will become thicker. At the recording line tip or recording line end,
When the ink is transferred as described above, the dot shape becomes unstable, which eventually leads to the occurrence of density unevenness.

Therefore, the present invention has been made in view of the above circumstances, and provides a peeling image forming method capable of suppressing uneven density by controlling the amount of light incident on the image forming layer in time series. Set as a target.

[0009]

According to an image recording method of the present invention, an image is formed by scanning a surface of a base material which supports at least a heat-meltable ink and a transfer layer in this order with a light beam carrying image information. Is recorded, and the ink softened / melted by the heat of the light beam is transferred to the transferred layer, and then the base material is peeled from the transferred layer. The surface of the base material is scanned with the light beams each having a required level of overshoot, and an image is recorded.

Alternatively, the surface of a substrate that supports at least the heat-meltable ink and the layer to be transferred is scanned with a light beam carrying image information to record an image, and the heat of the light beam softens and melts the image. A method for forming a peeling image, wherein the base material is peeled from the transferred layer after the ink is transferred to the transferred layer, and the light having a required level of overshoot applied to each rising portion. An image is recorded by scanning the surface of the base material with a beam, and the base material is peeled from the transferred layer in the main scanning direction from a portion where a light beam having an overshoot level is incident.

Alternatively, a light-heat conversion layer containing a light-converting substance, a heat-peeling layer having an average film thickness of 0.03 to 0.3 μm, and a coloring material are combined with the light-heat converting layer by the interposition of the heat-peeling layer. An image forming layer whose binding force with the photothermal conversion layer becomes smaller by irradiation of a light beam is formed by scanning the surface of the base material laminated with the light beam carrying image information with the image forming layer. After transferring the image to the image receiving layer,
A peeling image forming method in which the base material is peeled from the transferred layer, wherein an image is recorded by scanning the surface of the base material with the light beam having a required level of overshoot applied to each rising portion. It was done like this.

Alternatively, a light-heat conversion layer containing a light-converting substance, a heat-peeling layer having an average film thickness of 0.03 to 0.3 μm, and a coloring material are combined with the light-heat converting layer by interposing the heat-peeling layer. An image forming layer whose binding force with the photothermal conversion layer becomes smaller by irradiation of a light beam is formed by scanning the surface of the base material laminated with the light beam carrying image information with the image forming layer. After transferring the image to the image receiving layer,
A peeling image forming method in which the base material is peeled from the transferred layer, wherein an image is recorded by scanning the surface of the base material with the light beam having a required level of overshoot applied to each rising portion. The substrate is peeled from the layer to be transferred in the main scanning direction from the portion where the light beam having the overshoot level is incident.

[0013]

According to the above-mentioned means according to the present invention, after the transfer to the transfer layer, the base material and the transfer layer are separated from each other. , Each has a required level of overshoot. Here, paying attention to the transferred image, the tip portion thereof is prevented from being thinned by irradiating a high-output light beam. Therefore, by irradiating the overshoot portion of a required level to the light beam of the normal output, the thinning of the tip portion can be avoided at the time of peeling.

Further, by peeling the base material and the transferred layer from each other in the scanning direction of the light beam, the thickening of the rear end portion due to the tailing can be avoided. The heat transfer sheet to be applied is configured such that a photothermal conversion layer containing a photothermal conversion substance, a thermal peeling layer, and an image forming layer containing a coloring material are provided in this order on a support, and are bonded by interposing the thermal peeling layer. In the thermal transfer sheet in which the bonding force between the image forming layer and the photothermal conversion layer is reduced by irradiation with high-density energy light, the average thickness of the thermal release layer is limited to 0.03 to 0.3 μm. , A better recorded image can be obtained.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of an image recording apparatus to which the peeling image forming method according to the present invention is applied. The image signal carrying the image information having the required voltage level generated by the image signal generating means 101 is supplied to the input unit 103.

The input section 103 adjusts the duty ratio of the input image signal, supplies the image signal thus obtained to the voltage / current signal converting means 105, and also inputs a waveform in synchronization with the rising portion of the image signal. The timing signal is supplied to the overshoot current waveform generating means 107. The voltage / current signal converting means 105 converts the voltage change of the image signal into a current change, and supplies the image signal obtained by this to the waveform combining means 109.

Overshoot current waveform generating means 107
Generates a required level of overshoot and supplies the overshoot wave to the waveform synthesizing means 109. The waveform combining unit 109 combines the overshoot wave obtained by the overshoot current waveform generating unit 107 with the rising portion of the image signal obtained by the voltage / current signal converting unit 105. The output of the waveform combining unit 109 is output by the output unit 111.
Is supplied to.

As described above, the input section 103 to the output section 111 constitute the laser current control means 113. The laser current generated by the laser current control means 113 is supplied to the control end of the laser light generation means 115, and the emitted laser light intensity is externally modulated by the laser current.

The emitted laser light is incident on the thermal transfer sheet 121 wound on the rotary drum 117 which is rotationally driven in the direction of the arrow in the figure. The laser generating means 115 is movable in the illustrated direction on a precision moving rail (not shown) provided along the longitudinal direction of the rotating drum 117 in synchronization with the intermittent rotation of the rotating drum 117. An image is two-dimensionally recorded on the thermal transfer sheet 121 by moving the laser generator 115 and rotating the rotary drum 119.

In order to achieve the two-dimensional image recording, instead of moving the laser generating means 115, the laser may be reflected and scanned by a polygon mirror to irradiate the thermal transfer sheet with the laser. The thermal transfer sheet on which an image is recorded by scanning with the laser beam having a predetermined level of overshoot is peeled from the image receiving sheet. Peeling of the thermal transfer sheet is performed from the portion recorded at the overshoot level, and is performed along the scanning direction.

As described above, the thermal transfer sheet recorded at the overshoot level is first peeled from the image receiving sheet, so that the portion recorded by the overshoot level laser beam and the normal level laser beam are recorded. The recording line widths are substantially equal in the portion and the portion. Therefore, recording is performed with a substantially uniform recording line width over the entire thermal transfer sheet.

The relationship between the overshoot level of the laser current and the recording state at the tip of the recording line will be described below with reference to FIGS. The recording conditions for the thermal transfer sheet are
It is set according to the applied material, and in this embodiment, a thermal transfer sheet disclosed in Japanese Patent Application No. 5-275749 described later is applied, and a semiconductor laser beam having a wavelength of 830 nm has a beam diameter of 5 to 6 μm (half-value width). Focused at a main scanning speed of 10 m
/ S and a characteristic when recording is performed at a sub-scanning pitch of 10 μm.

FIG. 2 shows the output characteristics of the laser current, and the vertical axis and the horizontal axis show the laser light output and the output time, respectively. Here, P indicating the optical output during normal recording
The overshoot rate P1 / P0 (> 1) is set based on 0 and P1 indicating the maximum light output of the overshoot portion. Here, P0 = 100 mW and P1
= 130 mW.

FIG. 3 shows the shape of the recording line. The width W of the entire recording line and the total width W from the right end of the recording line are 5
% Position W1 and 5% position W of the full width W from the left end of the recording line
2 are set at the intersection A between the position W1 and the recording line edge, the distance L1 between the recording line tip, the intersection B between the position W2 and the recording line edge, and the distance L2 between the recording line tip. Based on this, thinness L = (L1 + L2) / 2 is set.

FIG. 4 shows the relationship between the thinness of the recording line tip (vertical axis) and the overshoot rate (horizontal axis). As shown, the overshoot rate is approximately 1.20 to 1.25.
From the above, it can be seen that the tip of the recording line is not thin. When the overshoot rate is approximately 1.20 to 1.25 or more, the tip of the recording line is not thinned, but increasing the overshoot rate causes a load on the laser light source to be increased and a life of the laser light source to be shortened. Become.

Therefore, in consideration of the above circumstances, it is preferable to set the overshoot rate to 1.30.

The relationship between the recording state at the recording line tip and the peeling direction will be described below. Fig. 5 shows the thinness of the recording line tip (vertical axis).
And the peeling direction (horizontal axis). As shown in the figure, it can be seen that when the peeling direction and the recording direction are matched, the recording line tip is not thinned, and when the peeling direction and the recording direction are not matched, the recording line tip is thinned. As the thermal transfer sheet to which the peeling image forming method according to the present invention can be applied, it is sufficient that an image of an arbitrary hue can be formed at a high resolution by a dry method. Thermal transfer sheet.

That is, a photothermal conversion layer containing a photothermal conversion substance, a thermal peeling layer, and an image forming layer containing a coloring material are provided in this order on a support, and are joined by interposing the thermal peeling layer. In the thermal transfer sheet, the bonding force between the image forming layer and the photothermal conversion layer is reduced by high-density energy light irradiation, and the average thickness of the thermal release layer is 0.03 to 0.
It is 3 μm.

In the above-mentioned thermal transfer sheet, since the photothermal conversion layer and the image forming layer of the thermal transfer sheet to be used are functionally separated, an image of an arbitrary hue can be formed and a thermal peeling layer is provided between both layers. Therefore, transfer of absorption of laser light in the photothermal conversion layer and discoloration (color mixing) of an image are avoided. Furthermore, since a material having a low thermal decomposition temperature is used for the heat release layer, the recording sensitivity is improved. Further, since the thickness of the image forming layer is small, high resolution can be obtained.

Preferred examples of the thermal transfer sheet will be shown below. The decrease in the binding force between the photothermal conversion layer and the image forming layer due to the high-density energy light irradiation reduces the binding force between the thermal peeling layer and the photothermal conversion layer, the bonding force between the thermal peeling layer and the image forming layer, or the aggregation of the thermal peeling layer. This is due to one or more types of weakness. The heat release layer includes a material having a heat change temperature lower than the heat conversion temperature of the light-heat conversion layer material.

The thermal change of the thermal release layer is thermal decomposition.
The thermal release layer contains a polymer. The polymer in the heat release layer is at least one selected from nitrocellulose and chlorinated polyolefin. The heat release layer contains a thermally decomposable low molecular weight compound in addition to the polymer.

The thermally decomposable low molecular weight compound is a gas generating compound. The exothermic decomposable compound in the heat release layer,
It is a low molecular weight compound having a thermal decomposition temperature of 280 ° C or lower. The exothermic decomposable compound in the heat release layer is at least one selected from diazonium compounds and azide compounds.

The change in heat of the light-heat conversion layer causes thermal decomposition and / or
Or, it is a shape change due to melting. The heat change temperature of the photothermal conversion layer is higher than the heat change temperature of the heat release layer by 20 ° C. or more. The heat conversion material of the light-heat conversion layer is carbon black and / or graphite.

The heat conversion material of the light-heat conversion layer is an infrared absorbing dye. The photothermal conversion layer contains a binder composed of a water-soluble polymer or an alcohol-soluble polymer. The average thickness of the photothermal conversion layer is 0.05 to 2 μ.
m. The light absorptivity of the photothermal conversion layer at a high-density energy light wavelength is 70% or more.

The support is made of a material transparent to high-density energy light. The support is polyethylene terephthalate. The image forming layer contains a coloring material and a polymer binder. The image forming layer contains a polymer having an average molecular weight of 5,000 to 100,000 as a binder.

The weight ratio of the coloring material to the binder in the image forming layer is 1: 5 to 10: 1. The image forming layer,
In addition to the coloring material and the binder, it contains a plasticizer. The image forming layer has a thickness of 0.1 to 1 μm. Further, in addition to the above-mentioned thermal transfer sheet, a thermal fusion type transfer sheet satisfying the above conditions can be applied, and for example, a thermal four color A3 super ink sheet CH787 thermal ink sheet manufactured by Seiko Denshi KK can be mentioned.

[0037]

According to the invention described above, a light beam having an overshoot larger than the output at the time of normal recording is applied to the start of peeling corresponding to the tip of the recording line, and the peeling end position corresponding to the rear end of the recording line is reached. In general, the output light beam at the time of recording is irradiated, whereby the amount of light incident on the image forming layer is controlled in time series, so that it is possible to suppress density unevenness of the recorded image.

Further, during peeling development, by thinning the base material and the transferred layer in the main scanning direction of the light beam, thinning is avoided at the peeling start position, so that unevenness in the density of the recorded image can be suppressed. it can. The thermal transfer sheet used in the image recording method according to the present invention has a thermal release layer having an average film thickness of 0.
By specifying the thin film material set to 03 to 0.3 μm, an image having more excellent density characteristics can be recorded.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image forming apparatus to which the present invention is applied.

FIG. 2 is a characteristic diagram showing the output of laser light generated by the laser light generating means shown in FIG.

FIG. 3 is an enlarged view showing a recording state of an image recorded by the laser light shown in FIG.

FIG. 4 is a graph showing the relationship between the thinness of the recording line tip (vertical axis) and the overshoot rate (horizontal axis).

FIG. 5: Thinness of recording line tip (vertical axis) and peeling direction (horizontal axis)
A graph showing the relationship with.

[Explanation of symbols]

 101 image signal generating means 103 input section 105 voltage / current signal converting section 107 overshoot current waveform generating section 109 waveform combining section 111 output section 113 laser current controlling section 115 laser light generating section 119 rotating drum 121 thermal transfer sheet

Claims (4)

[Claims] 1. A surface of a base material that supports at least a heat-meltable ink and a transfer layer in this order is scanned with a light beam carrying image information to record an image, and is softened / melted by the heat of the light beam. A method for forming a peeling image, wherein the base material is peeled from the transfer layer after the ink is transferred to the transfer layer, the light having a required level of overshoot applied to each rising portion. A peeled image forming method, wherein an image is recorded by scanning the surface of the substrate with a beam. 2. An image is recorded by scanning with a light beam carrying image information on the surface of a base material that supports at least the heat-meltable ink and the layer to be transferred in that order, and the image is softened and melted by the heat of the light beam. A method for forming a peeling image, wherein the base material is peeled from the transfer layer after the ink is transferred to the transfer layer, the light having a required level of overshoot applied to each rising portion. An image is recorded by scanning the surface of the base material with a beam, and the base material is peeled from the transferred layer in the main scanning direction from a portion where a light beam having an overshoot level is incident. Peeling image forming method. 3. A light-to-heat conversion layer containing a light-converting substance, a heat-releasing layer having an average film thickness of 0.03 to 0.3 μm, and a coloring material, which is bonded to the light-heat converting layer by interposing the heat-releasing layer. An image forming layer whose binding force with the photothermal conversion layer becomes smaller by irradiation of a light beam is formed by scanning the surface of the base material laminated with the light beam carrying image information with the image forming layer. A peeling image forming method in which an image is transferred to the image receiving layer, and then the base material is peeled from the transferred layer, wherein the light beam is provided with a required level of overshoot at each rising portion. A peeled image forming method, wherein an image is recorded by scanning the surface of a base material. 4. A light-to-heat conversion layer containing a light-converting substance, a heat-releasing layer having an average film thickness of 0.03 to 0.3 μm, and a coloring material, which is bonded to the light-heat converting layer by interposing the heat-releasing layer. An image forming layer whose binding force with the photothermal conversion layer becomes smaller by irradiation of a light beam is formed by scanning the surface of the base material laminated with the light beam carrying image information with the image forming layer. A peeling image forming method in which an image is transferred to the image receiving layer, and then the substrate is peeled from the transferred layer, wherein the light beam is provided with a required level of overshoot at each rising portion. A peeled image characterized in that an image is recorded by scanning the surface of the base material, and the base material is peeled from the transferred layer in the main scanning direction from a portion where a light beam having an overshoot level is incident. Forming method.