Recording device and recording control method

Abstract

To perform recording with high-coloring of a specific color and perform recording at high speed.SOLUTION: A recording device, which makes a recording head provided with a plurality of heater elements heat a sheet-like recording medium in which a plurality of coloring layers that color in response to heating while corresponding to a plurality of colors are piled up, so as to make desired coloring layers color to form an image on the recording medium, comprises the following configuration: each of the plurality of heater elements of the recording head is driven using a first pulse for preheating a prescribed coloring layer and a second pulse for coloring the prescribed coloring layer, which is applied following the first pulse and in coloring a specific color, the following control is performed: at least either of elongating a pulse width of the first pulse or increasing frequencies of applying the second pulse is controlled so that the other coloring layer which is not utilized in reproducing the specific color is prevented from coloring.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a printing apparatus and a printing control method, and more particularly to a printing apparatus and a printing control method for printing an image by heating a printing medium on which color-developing layers of different colors are superimposed, using heating elements. [Background technology]

[0002] In the past, monochrome printing using thermal paper and color printing using ink ribbons have been widely used in recording using thermal printheads. Meanwhile, in recent years, color recording using paper with multiple color-developing layers has been proposed and has become widespread as a simple means of printing photographs, etc. The multiple color-developing layers each require different heating temperatures and heating times to develop color, and color images are recorded by utilizing these differences to develop specific color-developing layers (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2013-506582 [Patent Document 2] Patent No. 4677431 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above conventional example, the pulse width of the head drive pulse used to cause each color layer to color was fixed, so multiple pulse applications were required to cause a specific color with a high color temperature to color, resulting in the problem of long heating times.

[0005] The present invention has been made in consideration of the above-mentioned conventional examples, and has an object to provide a printing apparatus and a printing control method that can achieve printing with high color development while shortening the heating time required to develop a specific color. [Means for solving the problem]

[0006] In order to achieve the above object, the recording apparatus of the present invention has the following configuration.

[0007] That is, a recording device for forming an image on a sheet-shaped recording medium on which a plurality of color-forming layers corresponding to a plurality of colors and which develop color in response to heating are superimposed, by heating a desired color-forming layer among the plurality of color-forming layers to develop color, An input means for inputting image data from a host device; The recording head has a plurality of heating elements, and a driving means drives each of the plurality of heating elements of the recording head using a first pulse for preheating a predetermined color-producing layer and a second pulse applied after the first pulse for causing the predetermined color-producing layer to color, and a pulse control means controls at least one of lengthening the pulse width of the first pulse and increasing the number of times the second pulse is applied, so as not to cause other color-producing layers not used in reproducing the specific color to color when a specific color is to be produced. The recording medium is formed with a first coloring layer that develops yellow (Y), a second coloring layer that develops magenta (M), and a third coloring layer that develops cyan (C) in that order from the side in contact with the plurality of heat elements of the recording head, and the driving means drives the recording head based on image data input by the input means to cause the first coloring layer, the second coloring layer, and the third coloring layer to develop in that order, forming an image on the recording medium, and the specific color is a color formed by coloring only of the second coloring layer, coloring only of the third coloring layer, and coloring by the second coloring layer and the third coloring layer. It is characterized by:

[0008] From another perspective of the present invention, An input unit for inputting image data from a host device, A recording control method for a recording device that uses a recording head having a plurality of heating elements to heat a sheet-shaped recording medium having a plurality of overlapping color-forming layers that correspond to a plurality of colors and develop color in response to heating, and forms an image on the recording medium by causing a desired color-forming layer among the plurality of color-forming layers to develop color, the method comprising: a control step of controlling at least one of lengthening the pulse width of the first pulse and increasing the number of times the second pulse is applied, when a specific color is to be developed by driving each of the plurality of heating elements of the recording head using a first pulse for preheating a predetermined color-forming layer and a second pulse that is applied after the first pulse and causes the predetermined color-forming layer to develop color, so as not to develop color in other color-forming layers that are not used to reproduce the specific color. The recording medium is formed with a first coloring layer that develops yellow (Y), a second coloring layer that develops magenta (M), and a third coloring layer that develops cyan (C) in that order from the side in contact with the multiple heat generating elements of the recording head, and the recording head is driven based on image data input by the input means to develop the first coloring layer, the second coloring layer, and the third coloring layer in that order to form an image on the recording medium, and the specific color is a color formed by coloring only the second coloring layer, coloring only the third coloring layer, and coloring by the second coloring layer and the third coloring layer. The present invention provides a recording control method.

[0009] From another aspect of the present invention, there is provided a recording apparatus for heating a sheet-shaped recording medium having a plurality of superposed color forming layers, each of which corresponds to a plurality of colors and develops color in response to heating, to cause a desired one of the plurality of color forming layers to develop color, thereby forming an image on the recording medium, the recording apparatus comprising: a recording head having a plurality of heat generating elements; drive means for driving each of the plurality of heat generating elements of the recording head using a first pulse for preheating a predetermined color forming layer and a second pulse applied after the first pulse for developing color in the predetermined color forming layer; transport means for transporting the recording medium in a first direction relative to the recording head; and control means for controlling the drive means to use the first pulse at a first pixel located in a non-image forming area of ​​the recording medium, and to use the second pulse at a second pixel located in an image forming area of ​​the recording medium and which is recorded after the first pixel. having The control means changes at least one of the duty ratio of the first pulse used at the position of the first pixel and the application time of the first pulse depending on whether the color-producing layer that produces color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer based on image data. When there are a plurality of desired color-forming layers, the control means reduces the duty ratio of the first pulse or shortens the application time of the first pulse in order to preheat a color-forming layer located at a deep position. The present invention is provided with a recording device characterized by the above-mentioned.

[0010] From another aspect of the present invention, there is provided a recording control method for a recording device that uses a recording head having a plurality of heating elements to heat a sheet-shaped recording medium having a plurality of superposed color forming layers that correspond to a plurality of colors and develop color in response to heating, thereby forming an image on the recording medium by causing a desired color forming layer among the plurality of color forming layers to develop color, the method comprising the steps of: driving each of the plurality of heating elements of the recording head using a first pulse for preheating a predetermined color forming layer and a second pulse that is applied after the first pulse and causes the predetermined color forming layer to develop color; The control is performed so that the first pulse is used at a first pixel located in an image non-forming area, and the second pulse is used at a second pixel located in an image forming area of ​​the recording medium and recorded after the first pixel, and at least one of the following is performed: a duty ratio of the first pulse used at the position of the first pixel is changed or an application time of the first pulse is changed depending on whether the color-developing layer that develops color at the position of the second pixel is a first color-developing layer or a second color-developing layer different from the first color-developing layer, based on input image data. When there are a plurality of desired color-forming layers, the duty ratio of the first pulse is reduced or the application time of the first pulse is shortened in order to preheat a color-forming layer located at a deep position. The present invention provides a recording control method. Effect of the Invention

[0011] According to the present invention, it is possible to realize recording with high color development while shortening the heating time required for color development of a specific color, and also to improve color development at the end portion where image formation starts. [Brief description of the drawings]

[0012] [Figure 1] 1 is a side cross-sectional view showing a schematic configuration of a recording apparatus according to a typical embodiment of the present invention. [Diagram 2] 2 is a block diagram showing the control configuration of the printing apparatus shown in FIG. 1 and a host apparatus connected thereto. [Diagram 3] 2 is a side cross-sectional view showing a detailed configuration of a recording head mounted on the recording apparatus shown in FIG. [Figure 4]4 is a side cross-sectional view showing a detailed structure of an ink ribbon heated by the recording head shown in FIG. [Diagram 5] 4 is a diagram for explaining the recording principle by the recording head shown in FIG. [Figure 6] 11 is a flowchart showing a conventional recording process as a comparative example. [Figure 7] 11A and 11B are diagrams illustrating control of a conventional example of a print head as a comparative example. [Figure 8] 6 is a flowchart showing the process of the recording device and the host PC when a print service according to the first embodiment is executed in the recording system. [Figure 9] 5A to 5C are diagrams illustrating an example of a heating pulse applied to a recording head of a recording device according to the process of the first embodiment. [Figure 10] 5 is a flowchart showing image processing for generating a heating pulse to drive a print head according to the first embodiment. [Figure 11] 11A to 11C are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to a first modified example of the first embodiment. [Figure 12] 13A to 13C are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to a second modified example of the first embodiment. [Figure 13] 13A to 13C are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to a third modified example of the first embodiment. [Figure 14] 10 is a flowchart showing the process of the printing apparatus and the host PC when a high-speed print service according to the second embodiment is executed in the printing system. [Figure 15] 11A and 11B are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to the process of the second embodiment. [Figure 16] 13A and 13B are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to a first modified example of the second embodiment. [Figure 17] 13A and 13B are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to a second modification of the second embodiment. [Figure 18] 13A and 13B are diagrams illustrating an example of a heating pulse applied to a recording head of a recording apparatus according to a third modified example of the second embodiment. [Figure 19] 1 is a diagram showing the relationship between an image I formed on an infrared imaging member 10 and a conveying direction D of the infrared imaging member 10. FIG. [Figure 20] 13A and 13B are diagrams showing examples of heating pulses applied to a recording head of a recording device according to a third embodiment. [Figure 21] 21 is a diagram for explaining the application timing of a preheat pulse to a previous pixel region IW different from that in FIG. 20. FIG. [Figure 22] 10 is a flowchart showing image processing for generating a heating pulse to drive a print head according to a third embodiment. [Diagram 23] 21 is a diagram for explaining the application timing of a preheat pulse to a previous pixel region IW different from that in FIG. 20. FIG. [Figure 24] FIG. 10 is a diagram showing an example in which heating pulses based on the heating pulses shown in FIG. 9 are used for application timings p0 to p8 of an image starting edge IA. [Diagram 25] FIG. 16 is a diagram showing an example in which heating pulses based on the heating pulses shown in FIG. 15 are used for application timings p0 to p8 at the image start edge IA. [Figure 26] 13 is a diagram illustrating a correction table that stores pixel values ​​of the immediately preceding pixel region IW after correction according to pixel values ​​of the image start end IA when the immediately preceding pixel region IW is made up of white pixels. FIG. [Figure 27] 10 is a flowchart showing image processing for generating a heating pulse to drive a printhead according to a fourth embodiment. [Figure 28] FIG. 13 is a diagram showing preheat instructions and table group numbers to be used according to combinations of specific colors in the immediately preceding pixel area IW and the image start edge IA. [Figure 29] FIG. 13 is a diagram illustrating a heating pulse for a combination of specific colors of pixels on the nth line and pixels on the (n+1)th line. [Diagram 30] FIG. 13 is a diagram showing an example of a preheat pulse and a subsequent heating pulse when the thermal history is high. [Diagram 31] FIG. 13 is a diagram showing an example in which preheating for an image start end IA is performed using only a preheat pulse for a previous pixel area IW. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] A preferred embodiment of the present invention will be described more specifically and in detail below with reference to the attached drawings. Note that the following embodiment does not limit the invention according to the claims. Although the embodiment describes a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0014] <Outline of the recording device (Figs. 1 to 3)> FIG. 1 is a side cross-sectional view showing a schematic configuration of a recording apparatus according to a typical embodiment of the present invention.

[0015] 1, the recording device 40 includes a recording head 30, a storage section 41, a transport roller 42, a platen 43, and an outlet 44. A plurality of sheet-shaped recording media 10 can be stored in the storage section 41, and the recording media 10 can be replenished by opening and closing a cover (not shown). During printing, the recording medium 10 is transported to the bottom of the recording head 30 by the transport roller 42, and after an image is formed between the platen 43 and the recording head 30, it is discharged from the outlet 44 and printing is completed.

[0016] Fig. 2 is a block diagram showing the control configuration of a recording system made up of the recording device and a host device connected thereto shown in Fig. 1. As shown in Fig. 2, this recording system is made up of the recording device 40 shown in Fig. 1 and a personal computer (host PC) 50 as its host device.

[0017] The host PC 50 includes a CPU 501 , a RAM 502 , a HDD 503 , a data transfer interface (I / F) 504 , a keyboard / mouse interface (I / F) 505 , and a display interface (I / F) 506 .

[0018] The CPU 501 executes processing according to the programs stored in the HDD 503 and the RAM 502. The RAM 502 is a volatile storage and temporarily stores programs and data. The HDD 503 is a non-volatile storage and also stores programs and data. The data transfer I / F 504 controls the transmission and reception of data with the recording device 40. This data transmission and reception and transfer method can be a wired connection such as USB, IEEE1394, or LAN, or a wireless connection such as Bluetooth (registered trademark) or WiFi. The keyboard / mouse (registered trademark) I / F 505 is an interface that controls a UI (user interface) such as a keyboard or mouse, and a user can input information to the host PC through this. The display I / F 506 controls the display on a display (not shown).

[0019] On the other hand, the recording device 40 includes a CPU 401 , a RAM 402 , a ROM 403 , a data transfer interface (I / F) 404 , a head controller 405 , and an image processing accelerator 406 .

[0020] The CPU 401 executes the processes of each embodiment described below in accordance with programs stored in the ROM 403 and the RAM 402. The RAM 402 is a volatile storage and temporarily stores programs and data. The ROM 403 is a non-volatile storage and stores table data and programs used in the processes of each embodiment described below. The data transfer I / F 404 controls data transmission and reception with the PC 50.

[0021] The head controller 405 controls a heating operation (described later) for the print head 30 based on the print data. Specifically, the head controller 405 is configured to read control parameters and print data from a predetermined address of the RAM 402. That is, when the CPU 401 writes the control parameters and print data to a predetermined address of the RAM 402, the head controller 405 starts processing and performs a heating operation of the print head.

[0022] The image processing accelerator 406 is configured with hardware, and executes image processing faster than the CPU 401. Specifically, the image processing accelerator 406 is configured to read parameters and data required for image processing from a predetermined address of the RAM 402. Then, when the CPU 401 writes the parameters and data to a predetermined address of the RAM 402, the image processing accelerator 406 is started and the predetermined image processing is executed.

[0023] The image processing accelerator 406 is not necessarily a necessary component, and the above table parameter creation process and image processing may be performed by the CPU 401 alone depending on the specifications of the recording device.

[0024] <Outline of the recording head configuration (Fig. 3)> FIG. 3 is a side cross-sectional view showing the configuration of a recording head and the state of the contact area between the recording head and a recording medium.

[0025] The print head 30 comprises a glaze 32 on a substrate 31. The glaze 32 may further comprise a "convex glaze" 33. A resistor 34 is disposed on the surface of the convex glaze 33 if present, or on the surface of the flat glaze 32 if not present. Preferably, an overcoat layer is formed on the resistor 34, the glaze 32 and the convex glaze 33. The combination of the glaze 32 and the convex glaze 33, which are generally made of the same material, is hereinafter referred to as the "print head glaze".

[0026] The substrate 31 is in contact with a heat sink 35 and is cooled using a fan or the like. The recording medium 10 is in contact with the glaze of the print head, which is generally of a length substantially greater than the length of the actual heating resistor. The resistor 34 is an electrothermal conversion element (heater or heating element) that generates heat when a current is supplied to it. A typical resistor has a length of about 120 μm in the transport direction of the recording medium 10, but the thermal contact area of ​​the recording medium with the glaze of a typical print head is 200 μm or more.

[0027] <Outline of recording principle (Figs. 4 and 5)> 4 is a cross-sectional view showing the structure of a sheet-like recording medium for use in image formation using infrared rays as a heat source. As described in detail below, the recording medium 10 is also called an infrared imaging member because it is made up of multiple color-forming layers that are heated and colored by heat rays (infrared rays) radiated from a resistor 34 when an electric current is supplied to the resistor, and a full-color image is formed by the coloring of these color-forming layers. Therefore, in this sense, the recording medium 10 will be referred to as an infrared imaging member in the following description.

[0028] 4, the thermal imaging member 10 includes image-forming layers 14, 16, 18, spacer layers 15, 17, and an overcoat layer 13 formed on a light-reflective substrate 12. The image-forming layers 14, 16, 18 are typically yellow (Y), magenta (M), and cyan (C), respectively, during full-color printing, but may be other color combinations.

[0029] Each image forming layer is initially colorless, but when each layer is heated to a specific temperature called the activation temperature, it becomes colored. The color order of the image forming layers can be selected arbitrarily. One preferred color order is as described above. Another preferred color order is that the three image forming layers 14, 16, and 18 are cyan (C), magenta (M), and yellow (Y), respectively. Here, an example will be described in which the layers are configured in the above-mentioned order of yellow (Y), magenta (M), and cyan (C).

[0030] Spacer layer 15 is preferably thinner than spacer layer 17, unless the materials comprising both layers have substantially the same thermal diffusivity. The function of the spacer layer is to control the thermal diffusion within the thermal imaging member 10. Preferably, spacer layer 17 is at least four times thicker than spacer layer 15 if it is composed of the same material. All layers disposed on substrate 12 are substantially transparent prior to imaging. If substrate 12 is a reflective color (e.g., white), the color image formed on thermal imaging member 10 is viewed through overcoat layer 13 against the reflective background provided by substrate 12. Because the layers disposed on substrate 12 are transparent, the combination of colors formed on each imaging layer is visible.

[0031] It is noted that although the three imaging layers 14 , 16 , 18 of the thermal imaging member 10 are disposed on the same side of the substrate 12 , some of the imaging layers may be disposed on opposite sides of the substrate 12 .

[0032] The imaging layers 14, 16, 18 are at least partially independently processed by variation of two adjustable parameters, temperature and time, which are adjustable such that an image is formed in the desired imaging layer by selecting the temperature of the recording head and the period of time during which the thermal imaging member is heated.

[0033] Here, each of the imaging layers 14, 16, 18 is treated by heating while a recording head 30 is in contact with the top layer of the member, i.e., the overcoat layer 13 of the thermal imaging member 10. The activation temperature (Ta3) of imaging layer 14 (the third layer counting from the substrate 12 and the imaging layer closest to the surface of the thermal imaging member 10) is greater than the activation temperature (Ta2) of imaging layer 16, which in turn is greater than the activation temperature (Ta1) of imaging layer 18.

[0034] Heating of the imaging layers at greater distances from the recording head 30 is delayed by the time required for heat diffusion through the spacer layers to those layers. This heating delay ensures that imaging layers closer to the recording head do not activate the imaging layers below them, even though those imaging layers have substantially higher activation temperatures than the lower imaging layers (layers further from the recording head), and are allowed to heat above their activation temperatures. Thus, in processing the top imaging layer 14, the recording head 30 briefly heats to a relatively high temperature, which insufficiently heats either imaging layer 16, 18 so that those layers are not activated.

[0035] Only the imaging layer closer to substrate 12 (in this case imaging layer 16 or 18) is activated by heating for a long enough period of time below the activation temperature of the imaging layer further from substrate 12. In this way, if the lower imaging layer is activated, the higher imaging layer is not activated.

[0036] Heating of the thermal imaging member 10 is preferably accomplished using the recording head 30, although any method of applying controlled heat to the thermal imaging member may be used, such as by any known means, such as by using a modulated light source (e.g., a laser light source).

[0037] FIG. 5 is a diagram illustrating the heating temperatures and times of the recording head required to process the three image forming layers shown in FIG.

[0038] In FIG. 5, the vertical axis represents the heating temperature on the surface of the infrared image member 10 that contacts the recording head 30, and the horizontal axis represents the heating time. Region 21 (where the recording head is at a relatively high temperature and for a relatively short heating time) provides imaging of the imaging layer 14, and region 22 (where the recording head is at an intermediate temperature and for an intermediate heating time) provides imaging of the imaging layer 16. Also, region 23 (where the recording head is at a relatively low temperature and for a relatively long heating time) provides imaging of the imaging layer 18. The time required for imaging the imaging layer 18 is substantially longer than the time required for imaging the imaging layer 14.

[0039] The activation temperature selected for the imaging layer is generally in the range of about 90° C. to about 300° C. The activation temperature (Ta1) of the imaging layer 18 is preferably as low and consistent as possible with respect to the thermal stability of the infrared image member during shipping and storage, and is preferably about 100° C. or higher. The activation temperature (Ta3) of the imaging layer 14 is preferably consistently low with respect to the activation of the imaging layers 16 and 18 by heating through this layer without being activated by the heating method of this embodiment, and is preferably about 200° C. or higher. The activation temperature (Ta2) of the imaging layer 16 satisfies Ta1 < Ta2 < Ta3, and is preferably between about 140° C. and about 180° C. The recording head 30 used herein includes a resistor array in which a plurality of resistors are linearly arranged so as to extend substantially over the entire width of the image (the direction orthogonal to the conveyance direction of the infrared image member).

[0040] Note that the recording width of the recording head may be shorter than the width of the image. In such a case, the recording head is configured to be moved relative to the infrared image member 10 or used in combination with another recording head in order to process the entire width of the image.

[0041] These resistors are supplied with current to provide heating pulses while the thermal imaging member is imaged as it is transported in a direction perpendicular to the direction of the resistors in the recording head. The time for which the thermal imaging member 10 is heated by the recording head 30 typically ranges from about 0.001 to about 100 milliseconds per line of the image. The upper limit is reasonably set based on the image printing time, while the lower limit is defined by the constraints of the electronic circuitry. The dot spacing of the formed image typically ranges from 100 to 600 lines per inch in both the direction of transport and the direction perpendicular to the direction of transport of the thermal imaging member 10, and may be different in each direction.

[0042] The recording device described above is a type of thermal printer, and the recording method employed by this device is also called the ZINK (Zero Ink) method or Zero Ink technology (registered trademark). EXAMPLES

[0043] Here, in order to emphasize the effect of the first embodiment, a conventional recording method will be described first as a comparative example, and then this embodiment will be described.

[0044] Explanation of Comparative Examples (Figs. 6 to 7) Fig. 6 is a flow chart showing the processing of the recording device 40 and the host PC 50 when a conventional print service is executed in the above-mentioned recording system. In Fig. 6, steps S601, S602, and S604-S606 show the processing of the host PC 50, and steps S611-S614 and S616-S617 show the processing of the recording device 40. Also, as shown in Fig. 6, when a user desires to print, the processing of the host PC 50 starts, and in response, the processing of the recording device 40 starts. Therefore, in step S611, the recording device 40 confirms that it is capable of printing, starts the print service, and becomes ready to print (Ready).

[0045] In this state, when the host PC 50 executes print service Discovery in step S601, the recording device 40 responds to that Discovery in step S612, notifying the recording device 40 that it is a device that can provide print services. Next, in step S602, the host PC 50 obtains print capability information. Basically, the host PC 50 requests the print capability information from the recording device 40, and in response in step S614, the recording device 40 notifies the recording device 40 of information on the print services it can provide.

[0046] Furthermore, the host PC 50 constructs a user interface for creating a print job based on the print capability information notified in step S604. Specifically, based on the print capability information of the recording device 40, appropriate options such as print size and printable paper size are displayed on the display and provided to the user. Next, in step S605, the host PC 50 issues a print job.

[0047] In response, the recording device 40 receives the print job in step S614 and executes the print job in step S616. When printing based on the print job is completed in the recording device 40, the recording device 40 notifies the host PC 50 of the printing completion in step S617. The host PC 50 receives the print completion notification in step S606 and notifies the user accordingly.

[0048] When the print job is completed, the host PC 50 and the recording device 40 each complete a series of print service processes.

[0049] In the above explanation, various types of information are transmitted by making a request from the host PC 50 to the recording device 40, and the recording device 40 responds to the request. However, the communication between the host PC and the recording device is not limited to the so-called pull type, and may be the so-called push type, in which the recording device 40 spontaneously transmits information to the host PC 50 (and other host PCs) on the network.

[0050] 7 is a diagram showing an example of a heating pulse applied to a recording head of a recording apparatus. In FIG. 7, timing p0 is the earliest in time, and the timing becomes later as one moves from the left to the right on the time axis.

[0051] On the left side of Fig. 7, each color to be developed is written, and on the right side, the corresponding heating pulse is written. For example, when developing yellow (Y), in order to realize the heating temperature and heating time of area 21 in Fig. 5, heating for a time of Δt1 is performed a total of two times with an interval of Δt0. Also, when developing magenta (M), in order to realize the heating temperature and heating time of area 22 in Fig. 5, heating for a time of Δt2 is performed a total of three times with an interval of Δt0. Similarly, when developing cyan (C), in order to realize the heating temperature and heating time of area 23 in Fig. 5, heating for a time of Δt3 is performed a total of four times with an interval of Δt0.

[0052] In addition, in Figure 7, for ease of understanding, it is assumed that the relationship Δt1 × 2 = Δt2 × 3 = Δt3 × 4 holds, and the total time of the heating pulses applied to the recording head 30 is the same regardless of which color is to be produced.

[0053] However, the heating time is t2 > Δt1+Δt0 > t1, t3 > Δt2+Δt0×2 > t2, Δt3+Δt0×3 > t3, The relative relationship of the heating time for each image forming layer is as follows: Heating time of Y < Heating time of M < Heating time of C Here, Y, M, and C refer to the image-forming layers 14, 16, and 18.

[0054] Here, the amount of heat applied by the recording head 30 is thermally conducted to the glaze 32, substrate 31 and heat sink 35 of the recording head 30 during the pulse interval Δt0, so that the temperature of the infrared imaging member 10 drops. Similarly, the amount of heat conducted to the infrared imaging member 10 is also thermally transferred to the platen 43 etc., so that the temperature of the infrared imaging member 10 drops by that amount. As a result, since the input energy is the same, the relative relationship of the peak temperatures of the image forming layers due to heating is as follows: Peak temperature of Y > Peak temperature of M > Peak temperature of C It becomes.

[0055] Where: Peak temperature of Y>Ta3 Ta3>M peak temperature>Ta2 Ta2>C peak temperature>Ta1 By controlling it in this way, it is possible to produce each of the colors Y, M, and C (primary colors) independently.

[0056] Next, we will explain the heating pulses that control the color development of the secondary colors R, G, and B and the tertiary color K. Here, a secondary color is a color that is reproduced using any two of the primary colors (i.e., Y, M, and C), and a tertiary color is a color that is reproduced using all of the primary colors.

[0057] For red (R) in FIG. 7, the heating pulse is controlled so that the colors develop in the order of yellow (Y) → magenta (M). Also, for green (G) in FIG. 7, the heating pulse is controlled so that the colors develop in the order of yellow (Y) → cyan (C). Similarly, for blue (B) in FIG. 7, the heating pulse is controlled so that the colors develop in the order of magenta (M) → cyan (C). Finally, for black (K) in FIG. 7, the heating pulse is controlled so that the colors develop in the order of yellow (Y) → magenta (M) → cyan (C).

[0058] In this comparative example, when each of the single colors yellow (Y), magenta (M), and cyan (C) is colored, only the last heating pulse contributes to color development, and the pulses before that play a role in preheating. In Fig. 7, among the pulses, the pulses mainly used for preheating (preheating pulses) are shaded, and the pulses mainly used for color development (image formation pulses: main pulses) are white. The timing of application of each heating pulse is as follows for each color. That is, Color Preheat Pulse Image Formation Pulse Application timing Application timing Y p0 p1 M p2, p3 p4 C p5, p6, p7 p8 R p0 p1,p2,p3,p4 G p0 p1,p5,p6,p7,p8 B p2, p3 p4, p5, p6, p7, p8 K p0 p1, p2, p3, p4, p5, p6, p7, p8 It is.

[0059] In this way, the driving pulses that can be used for actual image formation are each short. In particular, the pulse used for image formation of M among the monochrome colors M, C, and B is extremely short. This is because, when other colors are formed, the heating for the initial Y color formation has a preheating effect for the other colors.

[0060] Therefore, according to the comparative example described above, for colors that do not include yellow (Y), i.e., magenta (M) among magenta (M), cyan (C) and blue (B), most of the driving pulses used for coloring each color are used for preheating, resulting in a short coloring time. As a result, the coloring area on the infrared imaging member 10 is narrow, resulting in an image with low coloring.

[0061] For this reason, in the first embodiment, the following recording control process is executed in comparison with the comparative example described above.

[0062] Description of the embodiment (FIGS. 8 to 12) Fig. 8 is a flow chart showing the processing of the recording device 40 and the host PC 50 when executing the print service according to the embodiment 1 in the above-mentioned recording system. Note that in Fig. 8, the same processing steps as those already explained using Fig. 6 are given the same step reference numbers, and their explanation will be omitted.

[0063] 8, the recording device 40 confirms that it is capable of printing and also supports high color printing, and starts the print service. In response to the print service Discovery in the host PC 50 in step S601, the recording device 40 notifies the host PC 50 in step S612 that it is a device capable of providing print services including the high color printing service. Therefore, in step S613, the recording device 40 also notifies the host PC 50 of print capability information including information on the high color printing service.

[0064] In response to this, the host PC 50 notifies the user by displaying information for selecting whether to use the normal printing service or the high color printing service, specifically, by displaying the display of "printing service" and "high color printing service" and the options on the display etc. That is, in step S603, the process checks whether the instruction from the user is "printing service" or "high color printing service."

[0065] Here, if the user's selection is "print service", the process proceeds to step S605, where the same process as described in FIG. 6 is executed, but if the selection is "high color printing service", the process proceeds to step S603A. Then, in step S603A, the host PC 50 constructs a user interface for creating a high color print job based on the printable information. Specifically, based on the printable information from the recording device 40, the print size, printable paper size, etc. are displayed on the screen. Furthermore, the user is prompted to select a selection instruction according to the display. In addition, a highly colored preview image is displayed to allow the user to select a high color method, and the high color print job is created by such a method. Details of the high color print job creation will be described later with reference to FIGS. 10 to 11. After the high color print job is created, the process proceeds to step S605.

[0066] Meanwhile, in step S615, recording device 40 checks whether the received print job is a normal print job or a high color print job. If the received print job is a high color print job, processing proceeds to step S615A, where the high color print job is executed in the high color print mode, and then processing proceeds to step S617. On the other hand, if the received print job is a normal print job, processing similar to that described in FIG. 6 is executed.

[0067] Fig. 9 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to the process of Example 1. Note that in Fig. 9, explanations of the same configurations and symbols as those explained in Fig. 7 are omitted, and only the configurations unique to Example 1 will be explained here.

[0068] As shown in Fig. 9, the pulse width of the first pulse of the driving pulse group for color development of each color is lengthened to form a preheat pulse. In Fig. 9, the preheat pulses for high color development are indicated by thick diagonal lines and consist of the following three pulses. That is, A pulse having a pulse width Δt4 is applied at timing p2 for coloring M; A pulse having a pulse width Δt4 is applied at timing p5 for coloring C, A pulse with a pulse width of Δt4 is applied at timing p2 for coloring B, Here, the preheating time Δt4 is Δt4 < Y heating time Δt1 + Δt0, and Δt4 ≒ Δt1 The relative relationship of the heating time is as follows: Heating time of Y < Heating time of M < Heating time of C This is the same as the comparative example shown in FIG.

[0069] In this way, the pulse width Δt4 of the preheat pulse for high color development is During the preheating pulse for M color development, Y and C do not develop, Y and M do not develop during the preheating pulse for C color development. It is set as follows.

[0070] Here, the amount of heat applied by the recording head 30 is thermally conducted to the glaze 32, substrate 31, and heat sink 35 of the recording head 30 during the interval time Δt0, so the temperature of the infrared imaging member 10 drops. Similarly, the amount of heat conducted to the infrared imaging member 10 is also transmitted to the platen 43, etc., so the temperature of the infrared imaging member 10 drops by that amount. As a result, the input energy for coloring M and C increases by Δt4-Δt2 and Δt4-Δt3, respectively, but the peak temperatures due to heating are Peak temperature of Y > Peak temperature of M > Peak temperature of C This is the same as the comparative example shown in FIG.

[0071] In this respect, the pulse width Δt4 of the preheat pulse for high color development is During the preheating pulse for M color development, Y and C do not develop, Y and M do not develop during the preheating pulse for C color development. It is set as follows.

[0072] However, due to the presence of a preheating pulse, The coloring time of M when M is monochromatic is close to that of R and K. The color development time of C when the single color is developed is close to that of G, B, and K. The coloring time of M in B approaches that of R and K. By controlling in this way, the color development time is lengthened, the color development area on the infrared imaging member 10 is widened, and a highly colored image is formed. Specifically, the application timing of the preheat pulse and the image formation pulse constituting the heating pulse for each color is detailed as follows. That is, Color Preheat Pulse Image Formation Pulse Application timing Application timing Y p0 p1 M p2 p3,p4 C p5 p6,p7,p8 R p0 p1,p2,p3,p4 G p0 p1,p5,p6,p7,p8 B p2 p3,p4,p5,p6,p7,p8 K p0 p1, p2, p3, p4, p5, p6, p7, p8 As described above, the pulses that can be used for actual image formation are each longer.

[0073] 10 is a flowchart showing image processing for generating heating pulses to drive the recording head according to embodiment 1. This figure is a flowchart showing the details of the execution of the high color development print job in step S615A in FIG.

[0074] According to Fig. 10, in step S1001, the image data in the high color reproduction print job received in step S814 is input. Next, in step S1002, if the image data has been compressed or encoded, a decoding process is performed, and further, in step S1003, a color correction process is performed. This can be performed on the host PC 50 side, but it is preferable to perform it on the recording device 40 when performing color correction according to the characteristics of the recording device 40. Even at this point, the image data is in a general RGB data format. However, at this point, it is generally RGB data that reflects the characteristics of the recording device 40, so-called device RGB.

[0075] Next, in step S1004, luminance / density conversion is performed. In a typical thermal printer, when each pixel and each color component is expressed in 8 bits, C = 255 - R M = 255 - G Y = 255 - B Here, the following conversion is performed: In the case of preheat pulse control in this embodiment, for example, the preheat parameters when developing a single color of magenta (M) are different from the preheat parameters when developing a single color of red (R). Therefore, in order to set the two separately, it is desirable to perform luminance density conversion using a three-dimensional lookup table (3D_LUT). That is, C = 3D_LUT[R][G][B][0] M = 3D_LUT[R][G][B][1] Y = 3D_LUT[R][G][B][2] PM= 3D_LUT[R][G][B][3] PC= 3D_LUT[R][G][B][4] Here, PM and PC indicate the density values ​​corresponding to the preheat pulses when developing M and C colors, respectively.

[0076] Here, the above 3D_LUT is composed of 83886080 data tables of 256×256×256×5. Each data is the pulse width data to be applied at each timing p0 to p8 in FIG. 7. However, in order to reduce the amount of data, the number of grids may be reduced from 256 to 17, and 24565 data tables of 17×17×17×5 may be used to calculate the results using interpolation calculation. Of course, other than 17 grids, any suitable number of grids such as 16 grids, 9 grids, and 8 grids may be set as appropriate. Any method such as known tetrahedral interpolation may be used as the interpolation method.

[0077] Therefore, Yellow (Y) control pulse and preheat parameters Control pulses and preheat parameters that configure magenta (M), Control parameters and preheat parameters that configure cyan (C), Magenta and yellow control parameters and preheat parameters that make up red (R), Yellow and cyan control parameters and preheat parameters that make up green (G); Magenta and cyan control parameters and preheat parameters that make up blue (B); Yellow, magenta and cyan control parameters that make up black (K) and preheat parameters can be set independently.

[0078] Furthermore, in step S1005, output correction is performed. First, the pulse widths (c, m, y, pm, pc) for realizing the color development of each density component C, M, Y and the preheating (pm, pc) for the color development of magenta and cyan are calculated using a one-dimensional lookup table (1D_LUT). That is, c = 1D_LUT[C] m = 1D_LUT[M] y = 1D_LUT[Y] pm = 1D_LUT[PM] pc = 1D_LUT[PC] Here, the maximum value of c is Δt3, the maximum value of m is Δt2, the maximum value of y is Δt1, and the maximum values ​​of pm and pc are Δt4. The recording device 40 can modulate the color intensity of the infrared imaging member 10 by pulse width modulation (PWM), so if the above-mentioned c, m, y, pm, and pc are smaller than the maximum values, the pulse width can be appropriately shortened to achieve the desired gradation. This process may be performed by using a known means.

[0079] To realize the pulse control process shown in FIG. 9, for example, in the case of M single color (R=255, G=0, B=255), C = 3D_LUT

[0255] [0]

[0255] [0] = 0 M = 3D_LUT

[0255] [0]

[0255] [1] = Δt2 Y = 3D_LUT

[0255] [0]

[0255] [2] = 0 PM= 3D_LUT

[0255] [0]

[0255] [3] = Δt4 PC= 3D_LUT

[0255] [0]

[0255] [4] = 0 It must be set as follows.

[0080] Similarly, for C monochrome (R=0, G=255, B=255), C = 3D_LUT[0]

[0255]

[0255] [0] = Δt3 M = 3D_LUT[0]

[0255]

[0255] [1] = 0 Y = 3D_LUT[0]

[0255]

[0255] [2] = 0 PM= 3D_LUT[0]

[0255]

[0255] [3] = Δt4 PC= 3D_LUT[0]

[0255]

[0255] [4] = 0 It must be set as follows.

[0081] Furthermore, here, the heating pulse from the recording head 30 is modulated according to the temperature of the infrared imaging member 10 acquired by a temperature sensor (not shown) or the like. Specifically, the pulse width required to reach the activation temperature is controlled to be shorter as the acquired temperature becomes higher. This process may be performed by using known means. The temperature of the infrared imaging member 10 may not only be directly detected by a temperature sensor (not shown) or the like, but may also be estimated by the CPU 501 and controlled based on the estimated temperature. Any known method may be used as the method for estimating the temperature.

[0082] Furthermore, in step S1006, a preheat pulse for high color development is generated and synthesized, where the intensity of the preheat pulse for high color development is set to pre.

[0083] Next, the pulse width for forming an image and the preheat pulse are synthesized. That is, the pulse widths at the timings p0 to p8 are The pulses are synthesized as p0=y, p1=y, p2=max(m,pm), p3=m, p4=m, p5=max(c,pc), p6=c, p7=c, and p8=c. Here, max(x,y) is a function that sets the larger value of x and y. When realizing this by superimposing the pulses generated by each electric circuit, p2 = m or pm p5 = c or pc, where x or y represents the logical sum of signal x and signal y.

[0084] Next, in step S1007, head control is executed. That is, the pulse widths at the above timings p0 to p8 are controlled to form the desired color development and high color development processing on the infrared imaging member 10.

[0085] Next, in step S1008, it is checked whether recording of the page is complete. If the result is No, the process returns to step S1003 to record the rest of the page, and if the result is Yes, the print process ends.

[0086] Therefore, according to the embodiment described above, high color recording can be realized on a pixel-by-pixel basis on an infrared imaging member.

[0087] <Variation 1> Fig. 11 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 1 of Example 1. Note that in Fig. 11, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 1 of Example 1 are explained here.

[0088] Here, the preheat pulse indicated by the dark diagonal lines is always applied at timing p0. By controlling in this way, the color-developing heating pulse and the preheat pulse can be separated, simplifying the circuit control.

[0089] Also, as can be easily understood from FIG. 11, the shapes of the pulses that produce each color are very similar to each other. The difference in the degree of color development of C color among C, G, and B colors, The difference in the degree of color development of M color compared to R and B colors, can be made smaller, allowing for smooth color gradations to be expressed.

[0090] Furthermore, since the preheat pulse is applied at one point (timing p0), it is sufficient to set one type of preheat pulse, and there is an advantage that the amount of preheat control parameters can be reduced by half.

[0091] As a specific processing method, the luminance / density conversion using a three-dimensional lookup table is performed as follows. C = 3D_LUT[R][G][B][0] M = 3D_LUT[R][G][B][1] Y = 3D_LUT[R][G][B][2] P = 3D_LUT[R][G][B][3] Here, P represents the concentration value corresponding to the preheat pulse.

[0092] Next, calculate the pulse width to realize each C, M, Y concentration and preheat intensity. That is, c = 1D_LUT[C] m = 1D_LUT[M] y = 1D_LUT[Y] p = 1D_LUT[P] The pulse widths at the timings p0 to p8 are calculated as follows: Pulses are synthesized as p0=max(y,p), p1=y, p2=m, p3=m, p4=m, p5=c, p6=c, p7=c, and p8=c.

[0093] In addition, when realizing by superimposing pulses generated by electric circuits, the pulse width at timing p0 is p0=max(m,p) Here, x or y represents the logical sum of signal x and signal y.

[0094] By controlling the pulse width at each timing as described above, the heating position by the preheat pulse can be fixed, and a high color development recording mode capable of expressing smooth color gradation with a simpler system can be realized.

[0095] <Variation 2> Fig. 12 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 2 of Example 1. Note that in Fig. 12, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configuration unique to Modification 2 of Example 1 will be explained here.

[0096] Here, an example will be described in which a preheat pulse is realized by using a color generation pulse of another color without setting a dedicated preheat pulse.

[0097] Among the pulses shown in FIG. 12, the heating pulse group for preheating for high color development (those with dark diagonal lines) is the following three pulse group. A pulse with heating time Δt5 applied at timings p0 and p1 for M color development, C. A pulse of heating time Δt6 applied at timings p2, p3, and p4 for color development; A pulse with heating time Δt5 applied at timings p0 and p1 for B color development, It is.

[0098] Here, the preheating times Δt5 and Δt6 are, Δt5 < heating time Δt1 / 2 for Y, Δt6 < M heating time Δt2 / 2 In this way, the preheating times Δt5 and Δt6 are the heating times Δt1 for Y and Δt2 for M, respectively. Half The reason why the pulse width is set to 1 minute or less is as follows: the preheating pulse alone will not cause color development, and even if it is used in combination with a color development pulse for heating, the pulse width is set to a width that will not cause other colors to develop, and the pulse width can be set arbitrarily within this range.

[0099] Here, the preheating heating pulse is performed using a weak heating pulse for color development of another color that does not result in color development, thereby further simplifying the control.

[0100] As a specific processing method, in order to realize the heating pulse for preheating shown in FIG. 12, the luminance density conversion using a three-dimensional lookup table is performed as follows. That is, C = 3D_LUT[R][G][B][0] M = 3D_LUT[R][G][B][1] Y = 3D_LUT[R][G][B][2] Calculate the following.

[0101] To realize the process shown in FIG. 12, for example, in the case of M single color (R=255, G=0, B=255), C = 3D_LUT

[0255] [0]

[0255] [0] = 0 M = 3D_LUT

[0255] [0]

[0255] [1] = Δt2 Y = 3D_LUT

[0255] [0]

[0255] [2] = Δt1 / 2 It must be set as follows.

[0102] Similarly, for C monochrome (R=0, G=255, B=255), C = 3D_LUT[0]

[0255]

[0255] [0] = Δt3 M = 3D_LUT[0]

[0255]

[0255] [1] = Δt2 / 2 Y = 3D_LUT[0]

[0255]

[0255] [2] = 0 It must be set as follows.

[0103] By setting in this way, the subsequent processing is carried out in the same manner as in the comparative example, and a high color development recording mode can be realized with a simple configuration without setting a dedicated preheating heating pulse separately from the color development pulse.

[0104] Although the above description is directed to the single colors M, C, and B, the preheat control according to the present invention can also be applied to intermediate colors. For example, by setting an appropriate preheat pulse for a gradation from white to M, white to C, or white to B, it is possible to achieve high color development recording.

[0105] <Variation 3> Fig. 13 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 3 of Example 1. Note that in Fig. 13, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 3 of Example 1 will be explained here.

[0106] This example is a configuration that simultaneously achieves both the advantage of being able to smoothly express color gradation as described in Variation 1 of Example 1, and the advantage of being able to configure a dedicated preheating heating pulse as described in Variation 2 of Example 1 without having to set it separately from the color-developing pulse.

[0107] Among the pulses shown in FIG. 13, the heating pulse group for preheating for medium and high color development is the following three pulse group. A pulse with heating time Δt5 applied at timings p0 and p1 for M color development, C. A pulse with heating time Δt5 applied at timings p0 and p1 for color development; A pulse with heating time Δt5 applied at timings p0 and p1 for B color development, Here, the heating time Δt5 for preheating is expressed as follows, as explained in FIG. Δt5 < Heating time for Y Δt1 / 2 It is as follows.

[0108] As a specific processing method, in order to realize the heating pulse for preheating shown in FIG. 13, the luminance density conversion using a three-dimensional lookup table is performed as follows. That is, C = 3D_LUT[R][G][B][0] M = 3D_LUT[R][G][B][1] Y = 3D_LUT[R][G][B][2] Calculate the following.

[0109] figure 13 To realize the process described above, for example, in the case of M single color (R=255, G=0, B=255), C = 3D_LUT

[0255] [0]

[0255] [0] = 0 M = 3D_LUT

[0255] [0]

[0255] [1] = Δt2 Y = 3D_LUT

[0255] [0]

[0255] [2] = Δt1 / 2 It must be set as follows.

[0110] Similarly, for C monochrome (R=0, G=255, B=255), C = 3D_LUT[0]

[0255]

[0255] [0] = Δt3 M = 3D_LUT[0]

[0255]

[0255] [1] = 0 Y = 3D_LUT[0]

[0255]

[0255] [2] = Δt1 / 2 It must be set as follows.

[0111] By setting in this way, the subsequent processing is carried out in the same manner as in the comparative example, and a high color development recording mode can be realized with a simple configuration without setting a dedicated preheating heating pulse separately from the color development pulse. EXAMPLES

[0112] In the first embodiment, an example was described in which the preheat pulse contributes to extending the color development time to achieve high color development, but in this embodiment, an example is described in which the extension of the color development time is used to improve the printing speed.

[0113] Fig. 14 is a flow chart showing the processing of the recording device 40 and the host PC 50 when the high-speed print service according to the embodiment 2 is executed in the above-mentioned recording system. In Fig. 14, the same processing steps as those already explained using Fig. 6 are given the same step reference numbers, and the explanation thereof will be omitted.

[0114] 14, the recording device 40 confirms that it is capable of printing and also supports high-speed printing, and starts the print service. In response to the print service Discovery in the host PC 50 in step S601, the recording device 40 notifies the host PC 50 in step S612 that it is a device capable of providing print services including the high-speed print service. Therefore, in step S613, the recording device 40 also notifies the host PC 50 of print capability information including information on the high-speed print service.

[0115] In response to this, the host PC 50 notifies the user by displaying information for selecting whether to use the normal print service or the high-speed print service, specifically, by displaying the display and options of "print service" and "high-speed print service" on a display etc. In other words, in step S603', the process checks whether the instruction from the user is "print service" or "high-speed print service."

[0116] Here, if the user's selection is "print service", processing proceeds to step S604, where the same processing as described in FIG. 6 is executed, but if the selection is "high-speed print service", processing proceeds to step S603". Then, in step S603", the host PC 50 constructs a user interface for creating a high-speed print job based on the printable information. Specifically, based on the printable information from the recording device 40, the print size, printable paper size, etc. are displayed on the screen, and the user is prompted to select an appropriate option. In addition, the high-speed print job is created while the user is made aware of high-speed printing by, for example, displaying a preview image in high-speed animation. After the high-speed print job is created, processing proceeds to step S605.

[0117] Meanwhile, in step S615', the recording device 40 checks whether the received print job is a normal print job or a high-speed print job. If the received print job is a high-speed print job, the process proceeds to step S615'', where the high-speed print job is executed in the high-speed print mode, and then the process proceeds to step S617. On the other hand, if the received print job is a normal print job, the same process as described in FIG. 6 is executed.

[0118] Fig. 15 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to the process of Example 2. Note that in Fig. 15, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Example 2 will be explained here.

[0119] In this embodiment, the effect of increasing the number of pulses that contribute to color development by the preheating heating pulses is utilized to improve the printing speed while maintaining the density in the control configuration shown in the comparative example.

[0120] As shown in Fig. 15, when yellow (Y) is developed, in order to realize control that satisfies region 21 shown in Fig. 5 (where the temperature of the print head is relatively high and the heating time is relatively short), a heating pulse is applied twice for a heating time Δt1 within a time interval Δt0. Also, when magenta (M) is developed, a heating pulse is applied twice for a heating time Δt2 within a time interval Δt0. Similarly, when cyan (C) is developed, a heating pulse is applied three times for a heating time Δt3 within a time interval Δt0.

[0121] Now, comparing FIG. 15 with FIG. 7, the number of M heating pulses and C heating pulses is one less in the conventional case, so the heating pulse is too short for single color M, single color C, and M in B, resulting in weak color development. On the other hand, the decrease in color development for the other colors is small for the following reasons. The heating for the R color to produce the Y color acts as a preheating for the M color to produce. For G color, the heating for Y coloring acts as preheating for C coloring. The heating for the K color to develop Y color also serves as preheating for the M and C colors.

[0122] Therefore, as shown in FIG. 15, a preheating pulse with a longer pulse width (a pulse with thick diagonal lines in the figure) is applied once only immediately before the start of the heating pulses for M single color, C single color, and M color in B.

[0123] In this way, by using a preheating pulse with a longer pulse width, image formation for one pixel requires a total of seven timings p0 to p6, whereas in the comparative example and embodiment 1, nine timings p0 to p8 are required. As a result, recording can be performed at a speed about 20% faster.

[0124] In addition, in this embodiment 2 The image processing for generating heating pulses in accordance with the above and driving the recording head is almost the same as the processing described with reference to FIG. 10 in the first embodiment, so the description of the same processing will be omitted.

[0125] In this embodiment, the processes up to brightness density conversion and output correction are executed in the same manner as the pulse control described with reference to Fig. 10 in embodiment 1. In the subsequent preheat pulse generation & synthesis in step S1006, pulses are synthesized with the pulse widths at timings p0 to p6 as p0=y, p1=max(y, pm), p2=m, p3=max(m, pc), p4=c, p5=c, and p6=c.

[0126] In addition, when realizing this by superimposing pulses generated by electric circuits, it is sufficient to set p1=y or pm, p3=m or pc.

[0127] According to the embodiment described above, the printing speed can be improved by using the preheating pulse with a longer color development time.

[0128] <Variation 1> Fig. 16 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 1 of Example 2. Note that in Fig. 16, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 1 of Example 2 are explained here.

[0129] This modified example is an example that simultaneously achieves an improvement in printing speed by utilizing the longer color development time described in the second embodiment, and an improvement in the smoothness of gradation and a simplification of the control configuration described in the first modified example of the first embodiment.

[0130] 16, in this modification, as described in modification 1 of embodiment 1, a preheating heating pulse is applied at timing p0. Similarly to embodiment 2, when developing magenta (M), a driving pulse with a heating time Δt2 is applied a total of two times at a time interval Δt0. Furthermore, when developing cyan (C), a driving pulse with a heating time Δt3 is applied a total of three times at a time interval Δt0.

[0131] The image processing according to this modified example is the same as the processing explained with reference to the flowchart in FIG. 10, and therefore will not be explained further.

[0132] In this modified example, the processes up to the luminance density conversion and output correction are executed in the same manner as the pulse control described with reference to Fig. 10 in the first embodiment. In the subsequent preheat pulse generation & synthesis in step S1006, pulses are synthesized with the pulse widths at timings p0 to p6 set as p0=max(y,p), p1=y, p2=m, p3=m, p4=c, p5=c, and p6=c.

[0133] When implementing this by superimposing pulses generated by electric circuits, p0=y or p can be set.

[0134] By controlling in this manner, the preheating pulse is used at the beginning of the Y color development to extend the color development time, thereby improving the printing speed, while at the same time improving the smoothness of the gradation and simplifying the configuration.

[0135] <Variation 2> Fig. 17 is a diagram showing an example of a heating pulse applied to a recording head of a recording device according to Modification 2 of Example 2. Note that in Fig. 17, explanations of the same configurations and symbols as those explained in Fig. 7 and Fig. 9 are omitted, and only the configurations unique to Modification 2 of Example 2 are explained here.

[0136] This modified example is an example that simultaneously achieves both an improvement in printing speed by utilizing the longer color-developing time described in the second embodiment, and a configuration that simplifies control by using a color-developing pulse of a different color in addition to the preheating heating pulse, as described in the second modified example of the first embodiment.

[0137] In this modification, as explained in the second modification of the first embodiment, a preheating heating pulse is applied by utilizing a color-developing pulse of another color.

[0138] Specifically, in order to realize the preheating pulse shown in FIG. 17, The luminance-density conversion using a three-dimensional lookup table is performed as follows: C = 3D_LUT[R][G][B][0] M = 3D_LUT[R][G][B][1] Y = 3D_LUT[R][G][B][2] To realize the process shown in FIG. 17, for example, in the case of M single color (R=255, G=0, B=255), C = 3D_LUT

[0255] [0]

[0255] [0] = 0 M = 3D_LUT

[0255] [0]

[0255] [1] = Δt2 Y = 3D_LUT

[0255] [0]

[0255] [2] = Δt1 / 2 It must be set as follows.

[0139] Similarly, for C monochrome (R=0, G=255, B=255), C = 3D_LUT[0]

[0255]

[0255] [0] = Δt3 M = 3D_LUT[0]

[0255]

[0255] [1] = Δt2 / 2 Y = 3D_LUT[0]

[0255]

[0255] [2] = 0 It is necessary to be set as follows.

[0140] By setting it in this way, since the subsequent processing is executed in the same manner as in the comparative example, the high-speed recording mode can be realized with a simple control configuration without separately setting a dedicated preheating heating pulse and a coloring pulse. Also, in this example, similar to Modification Example 2 of Example 1, for example, appropriate preheating heating pulses can be set even in gradations from white to M color, or gradations from white to C color and white to B color, thereby realizing high-speed recording.

[0141] <Modification Example 3> FIG. 18 is a diagram showing an example of a heating pulse applied to a recording head of a recording apparatus according to Modification Example 3 of Example 2. In FIG. 18, descriptions of the same configurations and symbols as those described in FIGS. 7 and 9 are omitted, and here, only the configurations specific to Modification Example 3 of Example 2 will be described.

[0142] This modification example is an example that simultaneously realizes both the advantage that the color gradation can be smoothly expressed, which was described in Modification Example 1 of Example 2, and the advantage that it is not necessary to separately set a dedicated preheating heating pulse and a coloring pulse, which was described in Modification Example 2 of Example 1.

[0143] Among the pulses shown in FIG. 18, the preheating heating pulse group for medium-high coloring is the following three pulse groups. That is, pulses with a heating time Δt5 applied at timings p0 and p1 for M coloring, pulses with a heating time Δt5 applied at timings p0 and p1 for C coloring, pulses with a heating time Δt5 applied at timings p0 and p1 for B coloring, respectively. Here, the preheating heating time Δt5 is Δt5 < Δt1 / 2 of the heating time of Y, similar to that shown in FIG. 17.

[0144] Specifically, in order to realize the heating pulse for preheating shown in FIG. 18, the luminance density conversion using the three-dimensional lookup table is performed as follows. That is, C = 3D_LUT[R][G][B][0] M = 3D_LUT[R][G][B][1] Y = 3D_LUT[R][G][B][2] To realize the process shown in FIG. 18, for example, in the case of M single color (R=255, G=0, B=255), C = 3D_LUT

[0255] [0]

[0255] [0] = 0 M = 3D_LUT

[0255] [0]

[0255] [1] = Δt2 Y = 3D_LUT

[0255] [0]

[0255] [2] = Δt1 / 2 It must be set as follows.

[0145] Similarly, for C monochrome (R=0, G=255, B=255), C = 3D_LUT[0]

[0255]

[0255] [0] = Δt3 M = 3D_LUT[0]

[0255]

[0255] [1] = 0 Y = 3D_LUT[0]

[0255]

[0255] [2] = Δt1 / 2 It must be set as follows.

[0146] By setting in this way, the subsequent processes are executed in the same manner as in the comparative example, and the high-speed recording mode can be realized with a simple configuration without separately setting a dedicated heating pulse for preheating and a pulse for color development.

[0147] Also, although the processes in steps S1003 to S1006 in FIG. 10 are executed individually, they do not necessarily have to be executed individually, and the processes may be executed together in one step as follows. That is, the pulse widths at the timings p0 to p6 may be calculated as follows using a three-dimensional lookup table. That is, p0 = 3D_LUT[R][G][B][0] p1 = 3D_LUT[R][G][B][1] p2 = 3D_LUT[R][G][B][2] p3 = 3D_LUT[R][G][B][3] p4 = 3D_LUT[R][G][B][4] p5 = 3D_LUT[R][G][B][5] p6 = 3D_LUT[R][G][B][6] Calculate the following.

[0148] The above-mentioned timings p0 to p6 are set when the process of the second embodiment is combined into one step. In the case of the process of the first embodiment, p7 = 3D_LUT[R][G][B][7] p8 = 3D_LUT[R][G][B][8] Just add:

[0149] By carrying out such calculations, the pulse width for each timing at which the heater of the print head 30 is driven is uniquely determined, which has the advantage that it can be realized with a very simple configuration.

[0150] Furthermore, by adopting the above-mentioned configuration, it becomes possible to control any pulse according to the combination of the three colors YMC, which has the advantage of greatly increasing the degree of freedom in control. EXAMPLES

[0151] In the first embodiment, an example is described in which a preheat pulse contributes to a longer color development time to realize high color development, and in the second embodiment, an example is described in which the longer color development time is used to improve printing speed. Both of these embodiments are examples in which a preheat pulse is determined by performing brightness density conversion using a 3D_LUT for each color component of a recording device (thermal printer) from each pixel value of image data. In this embodiment, an example is described in which a preheat pulse for a pixel immediately preceding each pixel in the transport direction is determined from the value of each pixel in the transport direction to realize improved color development at the beginning of an image in the transport direction of the recording medium (infrared image member) 10 in FIG. 1.

[0152] As explained in the first embodiment, heating for the development of a certain color has a preheating effect for other colors that are developed after the first color. In other words, heating performed in advance in each pixel has a preheating effect for the subsequent heating. Such a preheating effect due to prior heating occurs not only within a pixel, but also between pixels.

[0153] FIG. 19 is a diagram showing the relationship between an image I formed on the infrared imaging member 10 and the conveying direction D of the infrared imaging member 10. As shown in FIG.

[0154] In FIG. 19, the shaded portion is image I, and in image I, the pixel region in which the most downstream pixels are arranged in a direction intersecting with the transport direction D is shown as image start end IA, and the other regions are shown as inner region IB. Also, in relation to the transport direction D, the region in which pixels without color-producing data just before image I are arranged in a direction intersecting with the transport direction D is shown as previous pixel region IW. That is, the pixels included in image start end IA are located on the upstream side with respect to the transport direction D, and the pixels included in previous pixel region IW are located on the downstream side. The image start end IA and inner region IB are included in the image forming region, and the previous pixel region IW is a non-image forming region. In FIG. 19, for example, when image I is recorded using the heating pulse shown in FIG. 7 in the comparative example, the preheating effect of previous pixel region IW on image start end IA is smaller than the preheating effect between pixels in inner region IB of the image. This is because there is no heating pulse for the white pixels continuing up to the pixel region IW immediately preceding the image start end IA, and therefore the pixels at the image start end IA receive little preheating from the pixel region IW immediately preceding the image start end IA.

[0155] In addition, in FIG. 7, in the case of C single color development, p5 to p7 are preheat pulses and p8 is an image formation pulse, but the image start point IA is an internal region. IB In other words, compared to the color development in the inner area IB, the color development area at the image start end IA is narrower in the transport direction, resulting in an image with low color development.

[0156] Fig. 20 is a diagram showing an example of a heating pulse applied to the recording head 30 of the recording device 40 according to the embodiment 3. Note that in Fig. 20, explanations of the same configurations and symbols as those explained in Fig. 7 are omitted, and only the configurations unique to the embodiment 3 will be explained here.

[0157] In FIG. 20, p'0 to p'8 indicate the heating timing in the pixel region IW immediately preceding the image start end IA, and p0 to p8 indicate the heating timing of the image start end IA. The heating pulse of the image start end IA in FIG. 20 is based on the heating pulse of FIG. 7, and the same is true for FIG. 21 and FIG. 22 described later. In FIG. 20, the diagonal lines indicate preheat pulses. The heat from the preheat pulse applied to the immediately preceding pixel region IW not only preheats the immediately preceding pixel region IW, but also has a preheating effect on the image start end IA. The heat from the pulse applied by the recording head 30 propagates not only in the depth direction of the infrared imaging member 10, but also partially in the transport direction to heat the infrared imaging member 10, so the preheat pulse of the immediately preceding pixel region IW also has a preheating effect on the image start end IA. Therefore, the difference in the preheating effect between the image start end IA and the internal region IB in FIG. 20 can be reduced. Specifically, the application timing of the preheat pulse and the image forming pulse constituting the heating pulse of each color is detailed as follows. That is, Color of the previous pixel area IW of the image start edge IA of the image start edge IA Preheating pulse Preheating pulse Imaging pulse Application timing Application timing Application timing Y p'8 p0 p1 M p'7, p'8 p2, p3 p4 C p'6,p'7,p'8 p5,p6,p7 p8 R p'8 p0 p1~p4 G p'6, p'7, p'8 p0 p1, p5~p8 B p'7, p'8 p2, p3 p4~p8 K p'8 p0 p1~p6 The heating pulse applied to the immediately preceding pixel region IW is a preheat pulse, unlike the heating pulse applied to the image start end IA, so the immediately preceding pixel region IW does not develop color. Also, in FIG. 20, the preheat pulse of the immediately preceding pixel region IW reflects the characteristics of each color.

[0158] First, one feature of preheating of the immediately preceding pixel area IW when the image start end IA is colored in each of the single colors Y, M, and C will be described.

[0159] The relationship between the preheat pulse widths of Y, M, and C in the immediately preceding pixel P is Y>M>C (Δt'1>Δt'2>Δt'3). Here, the explanation will be given using the preheat pulse width, but it can also be explained using the so-called duty ratio or duty cycle. The duty ratio or duty cycle is the ratio of the period during which the pulse (signal) is not zero in a certain period. In the example of FIG. 20, for the preheat pulse in the immediately preceding pixel region IW of Y, the certain period is Δt0, and the period during which the signal is not zero in the period Δt0 is Δt'1. Therefore, the duty ratio of the preheat pulse in the immediately preceding pixel region IW of Y is Δt'1 / Δt0. Similarly, the preheat pulse duty ratio in the immediately preceding pixel region IW of M is Δt'2 / Δt0, and the preheat pulse duty ratio in the immediately preceding pixel region IW of C is Δt'3 / Δt0.

[0160] In FIG. 20, Δt′1, Δt′2, and Δt′3 are depicted as one pulse with different widths, but the preheat pulse is not limited to this. For example, t '1, Δ t '2, Δ t The pulse width 3 may be divided into narrower pulses. In this case, the ratio of the total period during which the divided signals are not zero at Δt0 is the duty ratio or duty cycle. The relationship between the duty ratios of the Y, M, and C preheat pulses at the immediately preceding pixel P is Y>M>C (Δt'1 / Δt0>Δt'2 / Δt0>Δt'3 / Δt0).

[0161] Next, another feature of the preheating of the immediately preceding pixel area IW when the image start end IA is colored in each of the single colors Y, M, and C will be described.

[0162] The number of times of applying the preheating pulse for the immediately preceding pixel region IW of Y, M, and C is Y < M < C. In the example of FIG. 20, Y (1 time) < M (2 times) < C (3 times). Assuming Δt0 is the pulse period, since the period is a time, the total application time can be calculated by multiplying the period by the number of times. The application time of the preheating pulse for the immediately preceding pixel region IW of Y, M, and C is Y < M < C.

[0163] Y is formed in the image forming layer 14 of FIG. 4, and the activation temperature Ta3 is higher than the activation temperatures Ta2 and Ta1 of the image forming layers 16 and 18. Therefore, the preheating pulse width is widened to apply a high temperature to the infrared image member 10. At this time, the number of application timings is reduced so that the image forming layers 16 of M and 18 of C do not reach their respective activation temperatures Ta2 and Ta1. On the other hand, the activation temperature Ta1 of the image forming layer 18 that develops C is the lowest. Therefore, the preheating pulse width is narrowed to apply a low temperature to the infrared image member 10. At this time, since the heat diffusion at the low temperature generated by the applied preheating pulse is suppressed by the intermediate spacer layer 15 and spacer layer 17, by increasing the number of application timings, the heat at the low temperature is diffused to the image forming layer 18 of C. Since the image forming layer 16 that develops M is located between the image forming layer 14 of Y and the image forming layer 18 of C, both the preheating pulse width and the number of application timings are between Y and C.

[0164] Furthermore, the characteristics of preheating the immediately preceding pixel region IW when the image start IA is R or K coloring will be described.

[0165] In this case, the preheating pulse width is Δt’1 and the application timing is p’8. Since the image forming layer 14 of Y is used for the coloring of R and K, the characteristics of the preheating pulse are the same as those for Y single-color coloring.

[0166] Next, the characteristics of preheating the immediately preceding pixel region IW when the image start IA is G coloring will be described.

[0167] In this case, the preheat pulse width is Δt'3, and the application timing is p'6, p'7, and p'8. The Y image forming layer 14 is also used for G color development, and the preheat pulse for Y single color development exerts a particularly effective preheating effect on the Y image forming layer 14, but the preheat pulse for C image development does not. layer In the case of G color development, it is more preferable to prioritize the preheating effect on p5, p6, and p7 that develop C at the image start IA, and to use a preheat pulse similar to that used for C single color development. Since the Y image forming layer 14 is located shallower than the C image forming layer 18, the image formation is not sufficient even if a preheat pulse that prioritizes C color development is used. layer The preheat temperature can be higher than 18.

[0168] Finally, the characteristics of preheating the immediately preceding pixel area IW when the image start end IA is B color will be described.

[0169] In this case, the preheat pulse width is Δt'2, and the application timings are p'7 and p'8. Since the M image-forming layer 16 is used to develop the color B, the characteristics of the preheat pulse are the same as for the single color development of M. This preheat pulse and the preheat pulses with application timings p2 and p3 at the start of the image IA create an application time that can preheat the C image-forming layer 18.

[0170] Thus, the image Beginning IA It is preferable that the preheat pulse for the immediately preceding pixel region IW has the above characteristics in accordance with the color to be developed in the immediately preceding pixel region IW.

[0171] As described above, for R, B, and K, the same preheat pulse as that for monochromatic color development of the image forming layer with the highest activation temperature among the image forming layers to be activated is applied to the immediately preceding pixel region IW. Beginning IA This is because the image forming layer having the higher activation temperature is activated first. However, the present invention is not limited to this. Even if a preheat pulse for monochrome color development of another image forming layer is used, the preheat effect is at least achieved for each layer.

[0172] FIG. 21 is a diagram for explaining the application timing of the preheat pulse to the immediately preceding pixel region IW, which is different from that in FIG. Color of the previous pixel area IW of the image start edge IA of the image start edge IA Preheating pulse Preheating pulse Imaging pulse Application timing Application timing Application timing Y p'8 p0 p1 M p'6, p'7 p2, p3 p4 C p'3, p'4, p'5 p5, p6, p7 p8 R p'8 p0 p1~p4 G p'3, p'4, p'5 p0 p1, p5~p8 B p'6, p'7 p2, p3 p4~p8 K p'8 p0 p1~p6 It is.

[0173] In the example shown in FIG. 21, there are no overlapping preheat pulses in the application timings of Y, M, and C in the immediately preceding pixel region IW. Comparing the temperature changes over time of the Y image-forming layer 14 and the M image-forming layer 16, the image-forming layer 16, which is located deeper, is smaller, so it takes longer for the temperature to drop after the temperature is raised by the preheat pulses at application timings p'6 and p'7. The image-forming layer 18 of C is located even deeper, so it takes even longer for the temperature to drop. Therefore, even if a timing is provided where no application is made after the application of the M and C preheat pulses in the immediately preceding pixel region IW as in FIG. 21, the preheat effect is produced. However, because a temperature drop occurs at the timing where no preheat pulse is applied, the example shown in FIG. 20 has a greater preheat effect on the image start end IA.

[0174] Fig. 22 is a flowchart showing image processing for generating heating pulses to drive a recording head according to the third embodiment. This figure is a flowchart showing details of the print job execution in step S616 in each of Figs. 6, 8, and 14. Note that in Fig. 22, the same processing steps as those already explained in Fig. 10 are given the same step reference numbers, and their explanations are omitted. Here, only the processing steps unique to this embodiment will be explained.

[0175] According to Fig. 22, first, in step S1000, a flag value (described later) is initialized to "0". After that, in step S1001, image data is input, and in step S1002, if the image data has been compressed or encoded, a decoding process is executed. In step S1002-1, it is checked whether the line being processed (line n) in the direction perpendicular to the transport direction D is in the non-coloring range and the next line (n+1) is in the coloring range. If the result here is Yes, the process proceeds to step S1002a, and if the result is No, the process proceeds to step S1002-2.

[0176] In step S1002a, pixels of line n and line (n+1) of the image data are input in the direction perpendicular to the conveying direction D. In step S1002b, the same color correction process as in step S1003 is executed. Furthermore, in step S1002c, it is checked whether the pixel of line n is a specific color data. In this example, it is checked whether the specific color is "white", that is, whether R=255, G=255, B=255. Here, if the pixel is white, which is the specific color (Yes), the process proceeds to step S1002d, where the pixel of line n is processed as the previous pixel area IW. On the other hand, if the pixel is not a specific color (No), the process proceeds to step S1004.

[0177] Now, in step S1002d, the value of the flag is set to "1." Next, in step S1002e, a preheat luminance density conversion is executed using a three-dimensional lookup table for preheat (3D_LUTpre). In this process, pixel values ​​of the (n+1)th line of image data are input to 3D_LUTpre, and density values ​​corresponding to the preheat pulse of each pixel of n lines of white data are generated. That is, PY = 3D_LUTpre[R][G][B][0] PM = 3D_LUTpre[R][G][B][1] PC = 3D_LUTpre[R][G][B][2] Here, PY, PM, and PC respectively indicate density values ​​corresponding to the preheat pulse of the previous pixel area IW of the nth line of Y, M, and C colors. The pixels of the nth line correspond to the previous pixel area IW in FIG. 19, and the pixels of the (n+1)th line correspond to image Start IA Corresponds to.

[0178] Here, the above 3D_LUTpre is composed of 50,331,648 data tables of 256×256×256×3. Each data is density value data corresponding to the pulse width applied at each application timing p′0 to p′8 in FIG. 20 and FIG. 21. In order to reduce the data amount of the LUT, the number of grids may be reduced as in the 3D_LUT of the first embodiment. At which of the application timings p′0 to p′8 of each color the preheat pulse is applied may be determined in advance at the application timings shown in FIG. 20 and FIG. 21. A preheat pulse width, which will be described later and corresponds to a density value determined by 3D_LUTpre at a predetermined application timing may be applied. Furthermore, by setting density values ​​corresponding to the preheat pulse widths at the application timings p′0 to p′8 in 3D_LUTpre for each application timing, both the density value corresponding to the preheat pulse width and the application timing can be determined by 3D_LUTpre. That is, PY = 3D_LUTpre[R][G][B][0][1][2][3][4][5][6][7][8] PM = 3D_LUTpre[R][G][B][9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17] PC = 3D_LUTpre[R][G][B]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26] Calculate the following.

[0179] Here, [0] to [8], [9] to

[17] , and

[18] to

[26] correspond to the storage of preheat pulse width data of application timings p'0 to p'8, respectively.

[0180] Therefore, as shown in FIG. 20 and FIG. 21, the preheat parameters of the immediately preceding pixel region IW can be set independently for each color.

[0181] Next, in step S1002f, preheat output correction is performed. Specifically, a one-dimensional lookup table for preheat (1D_LUTpre) is used to calculate preheat pulse widths py, pm, and pc from density values ​​PY, PM, and PC corresponding to the preheat pulse widths. That is, py = 1D_LUTpre[PY] pm = 1D_LUTpre[PM] pc = 1D_LUTpre[PC] Then, in step S1002g, preheat pulse generation and synthesis are executed. Preheat pulses are set for application timings p'0 to p'8.

[0182] 20, there are cases where two or more of the preheat pulse widths py, pm, and pc have the same application timing. However, for one application timing, it is necessary to determine one of the preheat pulse widths. There are several methods for determining this.

[0183] For example, when it is given priority to prevent color development in the immediately preceding pixel region IW, the minimum values ​​of py, pm, and pc that are not 0 at each application timing are set at each application timing. That is, p'0 = min(py0, pm0, pc0) p'1 = min(py1, pm1, pc1) p'2 = min(py2, pm2, pc2) p'3 = min(py3, pm3, pc3) p'4 = min(py4, pm4, pc4) p'5 = min(py5, pm5, pc5) p'6 = min(py6, pm6, pc6) p'7 = min(py7, pm7, pc7) p'8 = min(py8, pm8, pc8) Here, the values ​​(0 to 8) added after py, pm, and pc correspond to the application timings. Note that when all of the preheat pulse widths py, pm, and pc are 0, the preheat pulse width is set to 0.

[0184] On the other hand, if priority is given to increasing the preheating temperature, the maximum widths of py, pm, and pc at each application timing are set to each application timing. That is, p'0 = max(py0, pm0, pc0) p'1 = max(py1, pm1, pc1) p'2 = max(py2, pm2, pc2) p'3 = max(py3, pm3, pc3) p'4 = max(py4, pm4, pc4) p'5 = max(py5, pm5, pc5) p'6 = max(py6, pm6, pc6) p'7 = max(py7, pm7, pc7) p'8 = max(py8, pm8, pc8) In addition, the balance may be adjusted by averaging or weighted averaging of py, pm, and pc at each application timing.

[0185] Furthermore, in step S1007, head control is executed. That is, by controlling the preheat pulse width to the above-set preheat pulse width at the application timings p'0 to p'8, a preheat pulse is applied to the immediately preceding pixel region IW, and an image is formed. Beginning IA It has a preheating effect.

[0186] Then, the process of step S1008 is executed to determine whether to continue processing the page or to end the process.

[0187] Now, in step S1002-1, if it is determined that the line (n) being processed is in the color gamut (No), the process proceeds to step S1002-2, where pixels of the nth line are input. After that, the above-mentioned steps S1003 and S1004 are executed. That is, the density values ​​of the pixels at the application timings p0 to p8 shown in Fig. 20, Fig. 21, and Fig. 23 described later are calculated.

[0188] In step S1004-1, it is checked whether the flag value is "1". If the flag value is "1" (Yes), the process proceeds to step S1004-2, where the flag value is set to "0". Then, the pixels on line n are processed as the image start point IA. Then, the process proceeds to step S1005'. On the other hand, if the flag value is "0" (No), the process proceeds to step S1004-3, where the pixels on line n are processed as the internal area IB.

[0189] In step S1005', output correction for the image start end is executed. Specifically, a one-dimensional lookup table (1D_LUTstart) for the image start end is used to calculate preheat pulse widths py, pm, and pc from density values ​​PY, PM, and PC corresponding to the preheat pulse widths. The preheat pulse widths calculated are the preheat widths at application timings p0 to p8, which are the image start end IA in Figs. 20 and 21 and Fig. 23 described below. That is, py = 1D_LUTstart[PY] pm = 1D_LUTstart[PM] pc = 1D_LUTstart[PC] Calculate the following.

[0190] Now, as can be seen by comparing FIG. 20 and FIG. 21 with FIG. 7, Δt″1, which is the preheat pulse width of py at application timing p0, is made narrower than Δt1 in FIG. 7. The reason for this is that a preheat pulse of Δt′1 is applied at application timing p′8 of the immediately preceding pixel region IW, and this is to prevent excessive preheating.

[0191] FIG. 23 is a diagram for explaining the application timing of the preheat pulse to the previous pixel region IW, which is different from FIG. 20. In FIG. 23, the preheat pulse width Δt″ is the same as Δt1 in FIG. 7, and Δt'1 is narrower than in FIGS. 20 and 21. The control for narrowing Δt'1 can be realized by 1D_LUTpre in step S1002f.

[0192] Returning to Fig. 22, in step S1006', preheat pulse generation and synthesis is performed similarly to step S1006 in Fig. 10. Thereafter, the process proceeds to step S1007.

[0193] On the other hand, in step S1004-3, the pixels on the nth line are set as the inner region IB and inner region output correction is executed. This is the same process as in step S1005. After that, the process proceeds to step S1006'.

[0194] Therefore, according to the embodiment described above, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner region IB can be reduced, and the color development of the image start edge IA can be improved.

[0195] In the above description, the 3D_LUTpre used in step S1002e generates only a preheat pulse, but in the case of the fifth embodiment described later, the 3D_LUTpre is changed to one having a heating pulse for developing a specific color of n-th line pixel. This configuration is the configuration of the 3D_LUT used in step S1004.

[0196] <Variation 1> The heating pulse used at the image start edge IA is not limited to the above example, and other heating pulses may be used.

[0197] FIG. 24 is a diagram showing an example in which heating pulses based on the heating pulses shown in FIG. 9 are used for application timings p0 to p8 of the image start end IA.

[0198] In the execution of the high color development print job in step S615A in Fig. 8, by applying the flowchart in Fig. 22, it is possible to generate heating pulses with application timings p'0 to p'8 for the previous pixel region IW and application timings p0 to p8 for the image start edge IA shown in Fig. 24. It is also possible to generate heating pulses with application timings p0 to p8 for the internal region IB. Note that the contents of 3D_LUTpre and 1D_LUTpre for the previous pixel region IW are changed to have the preheat pulse width in Fig. 24.

[0199] The contents of the 3D_LUT for the image start edge IA and the internal region IB are the same as those of the heating pulse shown in Figure 9. The contents of the 1D_LUTpre for the image start edge IA are changed and used so as to have the preheat pulse width shown in Figure 24. The 1D_LUT for the internal region IB is the same as that of the heating pulse shown in Figure 9. Looking at the widths of Δt'1 and Δt"1 shown in Figure 24, Δt"1 is controlled to be narrowed, but it is also possible to control Δt'1 to be narrowed as shown in Figure 23.

[0200] Therefore, with the above configuration, even in a high color print job, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner area IB can be reduced, and the color development of the image start edge IA can be improved.

[0201] Also, for the heating pulses in the configurations shown in FIGS. 11 to 13, by applying the above-described application of FIG. 9 to FIG. 24, it is possible to improve the color development at the image start point IA.

[0202] <Variation 2> Furthermore, the heating pulse used at the image start edge IA is not limited to the above example, and other heating pulses may be used.

[0203] FIG. 25 is a diagram showing an example in which heating pulses based on the heating pulses shown in FIG. 15 are used for application timings p0 to p8 of the image start end IA.

[0204] By applying the flowchart in FIG. 22 when executing a high-speed print job in step S615" in FIG. 14, heating pulses with application timings p'0 to p'6 for the previous pixel region IW and application timings p0 to p6 for the image start end IA shown in FIG. 25 can be generated. Heating pulses with application timings p0 to p6 for the internal region IB can also be generated. Note that the contents of 3D_LUTpre and 1D_LUTpre for the previous pixel region IW are modified to have the preheat pulse width in FIG. 25.

[0205] The contents of the 3D_LUT for the image start edge IA and the internal region IB are the same as the heating pulse shown in Figure 15. The contents of the 1D_LUTpre for the image start edge IA are changed and used so as to have the preheat pulse width shown in Figure 25. The 1D_LUT for the internal region IB is the same as the heating pulse shown in Figure 15. Looking at the widths of Δt'1 and Δt"1 shown in Figure 25, Δt"1 is controlled to be narrowed, but it is also possible to control Δt'1 to be narrowed as shown in Figure 23.

[0206] Therefore, with the above configuration, even in a high-speed print job, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner area IB can be reduced, and the color development of the image start edge IA can be improved.

[0207] Also, for the heating pulses in the configurations shown in Figs. 16 to 18, by applying the above-described application of Fig. 15 to Fig. 25, it is possible to improve the color development at the image start point IA. EXAMPLES

[0208] In the third embodiment, an example was described in which the color development improvement of the image start end IA in the transport direction of the recording medium (infrared imaging member) 10 shown in Fig. 19 is realized by generating a preheat pulse of the immediately preceding pixel region IW with reference to the pixel value of the image start end IA. In this embodiment, an example is described in which a preheat pulse is generated by correcting the pixel value of the immediately preceding pixel region IW according to the pixel value of the image start end IA.

[0209] FIG. 26 is a diagram illustrating a correction table that stores pixel values ​​of the previous pixel area IW after correction according to pixel values ​​of the image start end IA when the previous pixel area IW is made up of white pixels.

[0210] This correction table stores the corrected R, G, and B pixel values ​​of the previous pixel area IW for combinations of 256 gradations of R, G, and B at the beginning of the image IA. When the previous pixel area IW is a white pixel, the corrected pixel value of the previous pixel area IW can be calculated using the pixel value of the beginning of the image IA and the correction table shown in Figure 26. For example, for Y, M, C, R, G, B, and K, Color Image Beginning IA Pixel value of Corrected value of previous pixel area IW RGBRGB Y 255 255 0 255 255 240 M 255 0 255 255 196 255 C 0 255 255 128 255 255 R 255 0 0 255 240 240 G 0 255 0 128 255 128 B 0 0 255 196 196 255 K 0 0 0 240 240 240 The corrected value for the immediately preceding pixel region IW is used to generate a heating pulse in the same manner as for the image start end IA and the internal region IB. Note that, in the heating pulse based on the corrected value for the immediately preceding pixel region IW, it is desirable that the immediately preceding pixel region IW is not a visually noticeable color, and is a color that has a preheating effect on the color of the next image start end IA. Specifically, it is desirable that the pixel value has a similar hue to the pixel value of the image start end IA, and that the pixel value at the leading edge of the image is just short of a visually noticeable color. As shown in FIG. 26, a pixel value with a higher brightness than the image start end IA is set as the corrected pixel value for the immediately preceding pixel region IW.

[0211] Fig. 27 is a flow chart showing image processing for generating heating pulses to drive a recording head according to the fourth embodiment. This figure is a flow chart showing details of print job execution in step S616 in each of Figs. 6, 8, and 14. Note that in Fig. 27, the same step reference numbers are used for the same processing steps as those already explained in Figs. 10 and 22, and their explanations are omitted. Here, only the processing steps unique to this embodiment will be explained.

[0212] 27, after steps S1001 to S1002 are executed, if it is determined in step S1002-1 that the currently processed line (line n) is in the non-coloring range and the next (n+1) line is in the coloring range, the process proceeds to step S1002a. Then, steps S1002a to S1002c are executed. Then, if it is determined in step S1002c that the pixel of line n is specific color data, in this example, "white," that is, R=255, G=255, B=255 (Yes), the process proceeds to step S1002h. On the other hand, if the pixel is not of the specific color (No), the process proceeds to step S1004.

[0213] In step S1002h, n line pixels are processed as the previous pixel area IW. Specifically, the pixel values ​​of the n line corresponding to the previous pixel area IW are corrected using the n+1 line pixel values ​​corresponding to the image start end IA, using the correction table described in Fig. 26. Then, the process proceeds to step S1004.

[0214] After performing the luminance density conversion in step S1004, the process performs output correction in step S1005, and then performs S Execute 1006 preheat pulse generation & synthesis.

[0215] Thereafter, the process proceeds to steps S1007 to S1008.

[0216] 22, in this example, the luminance density conversion, output correction, preheat pulse generation, and synthesis processes corresponding to steps S1004 to S1006 can be performed in common regardless of the previous judgment results. Therefore, there is an advantage that the tables referenced in steps S1004 to S1006 can also be used in common regardless of the judgment results.

[0217] Therefore, according to the embodiment described above, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner region IB can be reduced, and the color development of the image start edge IA can be improved. EXAMPLES

[0218] In the third and fourth embodiments, if the previous pixel area IW contains white data, a preheat pulse is applied to the image start end IA to provide a preheat effect. In this embodiment, a preheat pulse is applied to the previous pixel area IW depending on the combination of specific colors of the previous pixel area IW and the image start end IA, including white data.

[0219] Fig. 28 is a diagram showing preheat instructions and table group numbers to be used according to combinations of specific colors in the immediately preceding pixel area IW and the image start end IA. Note that the flowchart shown in Fig. 22, which has already been described, can be used to execute this embodiment.

[0220] In step S1002c in Fig. 22, the table shown in Fig. 28 is referenced. For example, if the pixels on the nth line are R=255, G=255, and B=0, and the pixels on the (n+1)th line are R=0, G=255, and B=255, the preheat command is "Yes", so it is determined to be a specific color (Yes), and the process proceeds to step S1002d. Furthermore, in step S1002e, a 3D_LUT that can also have a heating pulse for developing a specific color as described in the first embodiment is used as 3D_LUTpre. This 3D_LUT also includes a preheat pulse for the image start IA.

[0221] By determining a number for identifying a table group in combination with the 1D_LUTpre used in step S1002f for each combination of specific colors in advance and managing them as in the table shown in Fig. 28, it is possible to set an appropriate table group by referring to the table. If the pixel on the nth line is R=255, G=255, B=0 (i.e., Y color) and the pixel on the (n+1)th line is R=0, G=255, B=255 (i.e., C color), the table group number is 12, and the table corresponding to this number is set for each process.

[0222] Fig. 29 is a diagram explaining heating pulses for a combination of specific colors of pixels on line n and pixels on line (n+1). In Fig. 29, the color written on the left side indicates the print color of the pixels on line n, and the color written on the right side indicates the print color of the pixels on line (n+1).

[0223] Consider the heating pulses applied at application timing p'0 and p'1 to the n-th line pixel R=255, G=255, B=0 (Y color) shown in FIG. 29, followed by the heating pulse applied at application timing p'5 to the (n+1)th line pixel R=0, G=255, B=255 (C color). In this case, the elapsed time is long, so the C image forming layer 18 is insufficiently preheated. Therefore, in the table of table group number 12 shown in FIG. 28, values ​​are set at application timings p'6, p'7, and p'8 of the n-th line pixel that can generate preheat pulses for the (n+1)th line pixel. Furthermore, when the print color of the n-th line pixel is R and the (n+1)th line pixel is C, the time from application timing p'4 to p5 is long, so the preheat pulse for the (n+1)th line is set at application timing p'8.

[0224] On the other hand, if the color development of the n-line pixel provides a sufficient preheating effect for the color development of the (n+1)-line pixel, there is no need to set a preheat pulse for the (n+1)-line pixel in the n-line pixel. For example, as shown in Fig. 29, if the n-line pixel is K and the (n+1)-line pixel is C, the heating for coloring the n-line pixel provides sufficient preheating for the (n+1)-line pixel as well, so there is no need to set a preheat pulse.

[0225] When the nth line pixel is R=0, G=0, B=0 and the (n+1)th line pixel is R=0, G=255, B=255, the preheat command is "No" according to the table in Fig. 28. Therefore, in step S1002c in Fig. 22, it is determined that the color is not a specific color (No), and the process proceeds to step S1004.

[0226] In FIG. 22, in steps S1005', S1006', and S1004-3, a table is used, and the processing is performed using a table corresponding to a table group number corresponding to a set of n-th line pixel and (n+1)-th line pixel.

[0227] Therefore, according to the embodiment described above, the difference between the preheating effect on the image start edge IA and the preheating effect on the inner region IB can be reduced, and the color development of the image start edge IA can be improved.

[0228] In the above description, an example in which the process of the flowchart shown in FIG. 22 is applied has been described, but the process of this embodiment can be executed by applying the process of the flowchart shown in FIG.

[0229] That is, in step S1002c in Fig. 27, the table shown in Fig. 28 is referenced. For example, if the nth line pixel is R=255, G=255, B=0 and the (n+1)th line pixel is R=0, G=255, B=255, the preheat instruction is "yes" so it is determined to be a specific color (Yes) and the process proceeds to step S1002h. Also, if the nth line pixel is R=0, G=0, B=0 and the (n+1)th line pixel is R=0, G=255, B=255, the preheat instruction is "no" so it is determined to be not a specific color (No) and the process proceeds to step S1004.

[0230] When applying the flowchart shown in FIG. 27, it is only necessary to set a table group number so that the table used in step S1002h can be set according to a combination of specific colors. EXAMPLES

[0231] In the third to fifth embodiments, examples of setting the preheat pulse of the immediately preceding pixel region IW that is set and applied are described. In this embodiment, an example of changing the width or application timing of the preheat pulse of the immediately preceding pixel region IW according to the thermal history is described. The reason for changing the preheat pulse width or application timing according to the thermal history is to reduce the excess or deficiency of the preheat effect. The thermal history is the ambient temperature of the infrared imaging member 10 detected by a thermistor, or the history of the estimated temperature of each layer of the immediately preceding pixel region IW of the infrared imaging member 10 based on the pattern of the heating pulse applied before the immediately preceding pixel region IW.

[0232] The temperature of each image-forming layer for each color developed can be estimated from the known activation temperatures of the image-forming layers 14, 16, and 18 of the infrared imaging member 10 and the colors developed by printing various images in experiments. In addition, the temperature of a thermistor (not shown) provided in the recording device 40 at the time of color development during each printing is recorded, and the correspondence between the temperature of the thermistor and the estimated temperature of each image-forming layer is tabulated. Alternatively, the correspondence between the heating pulse pattern for the colors developed in the experiment and the estimated temperature of each image-forming layer may be tabulated.

[0233] When the print job of step S616 is executed, when the high color print job of step S615A is executed, and when the high speed print job of step S615'' is executed, the temperature of the previous pixel region IW can be estimated from the temperature of the thermistor or the pattern of the heating pulse by referring to the table described above.

[0234] In this embodiment, the preheat pulse width and application timing of the application timings p'0 to p'8 in Figures 20, 21, and 23 are changed depending on the estimated temperature. Specifically, a plurality of 3D_LUTpre capable of calculating both the preheat pulse width and application timing described in the third embodiment are prepared in advance according to temperature, and the 3D_LUTpre corresponding to the estimated temperature is selected. In this way, the preheat pulse width and application timing of the application timings p'0 to p'8 can be changed.

[0235] In this change, the higher the temperature is, the narrower the preheat pulse width is, or the number of application timings is reduced.

[0236] Fig. 30 is a diagram showing an example of a preheat pulse and a subsequent heating pulse when the thermal history is at high temperature, whereas Fig. 20 shows a preheat pulse width of an n-line pixel when the thermal history is at room temperature.

[0237] As can be seen by comparing FIG. 30 with FIG. 20, when the colors are Y, R, and K, the preheat pulse width Δt'1 at application timing p'8 is narrower in FIG. 30 than in FIG. 20. Also, when the colors are M and B, in FIG. 30, the preheat pulse is not applied at application timing p'7. When the colors are C and G, in FIG. 30, the preheat pulse is not applied at application timing p'6. Here, the two patterns of FIG. 20 and FIG. 30 are described, but three or more patterns with different preheat pulse widths or different numbers of application timings may be used depending on the thermal history. Also, it is advisable to set in advance in 3D_LUTpre the preheat pulse width and application timing that exert a preheating effect on the image start end IA without causing visible color development in the immediately preceding pixel region IW, depending on the temperature.

[0238] Therefore, according to the embodiment described above, the difference between the preheating effect on the image leading edge IA and the preheating effect on the inner region IB can be reduced according to the thermal history, and the color development of the image leading edge IA can be improved.

[0239] <Other Examples> As with the internal region IB, in the third to sixth embodiments, the heating pulse for the image start end IA includes a preheat pulse. However, the present invention is not limited to this configuration. For example, preheating for the image start end IA may be performed only by the preheat pulse for the immediately preceding pixel region IW.

[0240] FIG. 31 is a diagram showing an example in which preheating for the image leading edge IA is performed only by a preheat pulse for the immediately preceding pixel region IW.

[0241] The characteristics of the preheat pulse shown in FIG. 31 will be described below in comparison with FIG.

[0242] In the case of Y, by applying the preheat pulse of the immediately preceding pixel region IW and the pulse of the image start end IA in FIG. 20 earlier by Δt0, the image start end IA becomes only an image formation pulse as shown in FIG.

[0243] In the case of M, by applying the preheat pulse in the immediately preceding pixel region IW in Figure 20 earlier by Δt0 and applying the pulse at the image start IA earlier by Δt0 × 2, the image start IA will have only an image formation pulse, as shown in Figure 31. Here, the number of preheat pulses has been reduced from four to three because, unlike Figure 20, the preheat pulses can be applied at continuous application timing, resulting in a high preheat effect, and leaving the number of preheat pulses at four would cause M to develop color in the immediately preceding pixel region IW.

[0244] In the case of C, by applying the pre-heat pulse in the immediately preceding pixel region IW in Figure 20 earlier by Δt0 × 2 and applying the pulse at the image start IA earlier by Δt0 × 8, the image start IA will have only an image formation pulse, as shown in Figure 31. Here, the number of pre-heat pulses has been reduced from six to five because, unlike Figure 20, the pre-heat pulses can be applied at continuous application timing, resulting in a high pre-heat effect, and leaving the number of pre-heat pulses at six would cause C to develop color in the immediately preceding pixel region IW.

[0245] In the case of R, by applying the preheat pulse of the immediately preceding pixel region IW and the pulse of the image start end IA in FIG. 20 earlier by Δt0, the image start end IA becomes only an image formation pulse as shown in FIG.

[0246] In the case of G, by applying the preheat pulse in the immediately preceding pixel region IW in FIG. 20 and the pulse at the image start point IA earlier by Δt0, the image start point IA becomes only an image formation pulse as shown in FIG.

[0247] In the case of B, by applying the pre-heat pulse in the immediately preceding pixel region IW in Figure 20 earlier by Δt0 and applying the pulse at the image start edge IA earlier by Δt0 × 2, the image start edge IA only has an image formation pulse, as shown in Figure 31. Here, the number of pre-heat pulses has been reduced from four to three because, unlike Figure 20, the pre-heat pulses can be applied at continuous application timing, resulting in a high pre-heating effect, and leaving the number of pre-heat pulses at four would cause M to develop color in the immediately preceding pixel region IW.

[0248] In the case of K, by applying the preheat pulse in the immediately preceding pixel region IW in FIG. 20 and the pulse at the image start point IA earlier by Δt0, the image start point IA becomes only an image formation pulse as shown in FIG.

[0249] As described above, the color development at the beginning IA of the image can be improved by applying a pulse at the timing shown in FIG.

[0250] As explained above, the color development efficiency can be increased by setting the preheating pulse according to a combination of the three stimulus values ​​of RGB, CMY, etc. This improvement in color development efficiency can be used to achieve high color development and high-speed recording.

[0251] In order to simplify the process of determining whether or not a preheating heating pulse is required based on a combination of the three stimulus values, a configuration may be adopted in which the determination is whether or not Y=0 (whether or not B=255), and the preheating heating pulse is used if the determination result is Yes.

[0252] This is because the infrared imaging member 10 has a Y color-forming layer closest to its surface, which has the highest color-forming temperature, and therefore has a preheating effect on the coloring of other colors. Of course, if the infrared imaging member 10 has another color, for example, an M color-forming layer closest to its surface, which has the highest color-forming temperature, it is appropriate to determine whether M=0 (G=255).

[0253] Furthermore, in the above-described embodiment, the recording device and the host device are separate, but the host device as the source of image data may be an imaging device such as a digital camera. In this case, a device in which the recording device and the digital camera are integrated, that is, a recording device with a photographing function, is also included in the present invention.

[0254] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0255] 10 recording medium (infrared image member), 12 substrate, 13 protective film layer, 14, 16, 18 image forming layer, 15, 17 spacer layer, 30 recording head, 31 substrate, 32 glaze, 33 convex glaze, 34 resistor, 35 heat sink, 40 recording device, 41 storage section, 42 conveying roller, 43 platen, 44 discharge port, 50 host PC

Claims

1. A recording device for forming an image on a sheet-like recording medium having a plurality of color-forming layers that correspond to a plurality of colors and that develop color in response to heating, by heating a desired color-forming layer among the plurality of color-forming layers to develop color, comprising: An input means for inputting image data from a host device; A recording head having a plurality of heating elements; a driving means for driving each of the plurality of heat generating elements of the recording head by using a first pulse for preheating a predetermined color forming layer and a second pulse for causing the predetermined color forming layer to color, the second pulse being applied after the first pulse; a pulse control means for controlling, when a specific color is to be developed, at least one of extending the pulse width of the first pulse and increasing the number of times the second pulse is applied so as not to develop color in other color-developing layers that are not used for reproducing the specific color; the recording medium is formed with a first coloring layer that develops a yellow (Y) color, a second coloring layer that develops a magenta (M) color, and a third coloring layer that develops a cyan (C) color, in that order from the side that contacts the plurality of heat generating elements of the recording head; the driving means drives the recording head based on the image data input by the input means to cause the first color forming layer, the second color forming layer, and the third color forming layer to develop colors in this order, thereby forming an image on the recording medium; A recording device characterized in that the specific color is a color formed by coloring only the second color-forming layer, a color formed by coloring only the third color-forming layer, and a color formed by coloring both the second color-forming layer and the third color-forming layer.

2. The input means inputs an instruction as to whether or not to further enhance color development, 2. The recording apparatus according to claim 1, wherein when there is an instruction for high color development, control is performed by the pulse control means.

3. The pulse control means When the second color forming layer or the third color forming layer is to be colored independently, the pulse width of the first pulse used for preheating the color forming layer to be colored is made longer; A recording device as described in claim 1 or 2, characterized in that when the second color-forming layer and the third color-forming layer are caused to color, the pulse width of the first pulse used to preheat the second color-forming layer is controlled to be longer.

4. The recording device according to claim 1 or 2, wherein the pulse control means controls to lengthen the pulse width of the first pulse so that preheating of other color layers is performed at the same timing and with the same pulse width as preheating of the color layer to be colored at an earlier timing, regardless of the color layer to be colored.

5. The recording device according to claim 1 or 2, characterized in that the pulse control means controls the application timing of the first pulse, which preheats the color-forming layer to be colored, to match the application timing of at least the second pulse, which is used to color a color-forming layer other than the color-forming layer.

6. A recording device that heats a sheet-like recording medium having a plurality of superimposed color-forming layers that correspond to a plurality of colors and that change color in response to heating, and causes a desired color-forming layer among the plurality of color-forming layers to change color and form an image on the recording medium, A recording head having a plurality of heating elements; a driving means for driving each of the plurality of heat generating elements of the recording head by using a first pulse for preheating a predetermined color forming layer and a second pulse for causing the predetermined color forming layer to color, the second pulse being applied after the first pulse; a pulse control means for controlling, when a specific color is to be developed, at least one of extending the pulse width of the first pulse and increasing the number of times the second pulse is applied so as not to develop color in other color-developing layers that are not used for reproducing the specific color; The recording device is characterized in that the pulse control means controls the application timing of the first pulse so that preheating of the color-forming layer to be colored is performed at the same timing as preheating of the color-forming layer to be colored at an earlier timing regardless of the color-forming layer to be colored, and controls the application timing of the first pulse for preheating the color-forming layer to be colored to match the application timing of at least the second pulse used for coloring a color-forming layer other than the color-forming layer.

7. said input means further inputs an instruction as to whether or not to perform high speed recording; 2. The recording apparatus according to claim 1, wherein when an instruction for high speed recording is given, control is performed by said pulse control means.

8. The pulse control means When the second color-forming layer or the third color-forming layer is caused to develop color independently, the pulse width of the first pulse used to preheat the color-forming layer to be developed is lengthened, and the first pulse having the lengthened pulse width is applied once immediately before the application of the second pulse for color development of the color-forming layer to be developed; A recording device as described in claim 1 or 7, characterized in that, when the second color-forming layer and the third color-forming layer are caused to color, the pulse width of the first pulse used to preheat the second color-forming layer is lengthened, and the first pulse with the longer pulse width is applied once just before applying the second pulse to cause the second color-forming layer to color.

9. The recording device according to claim 1 or 7, wherein the pulse control means controls so that the pulse width of the first pulse is lengthened so as to preheat the other color-forming layers at the same timing and with the same pulse width as the preheating of the color-forming layer to be colored at an earlier timing, regardless of the color-forming layer to be colored, and controls so as to apply the first pulse with the longer pulse width once.

10. The recording device according to claim 1 or 7, characterized in that the pulse control means controls the application timing of the first pulse, which preheats the color-forming layer to be colored, to coincide with at least the second pulse, which is used to color a color-forming layer other than the color-forming layer.

11. The recording device described in claim 1 or 7, characterized in that the pulse control means controls the application timing of the first pulse so that preheating of the color layer to be colored is performed at the same timing as preheating of the color layer to be colored at an earlier timing regardless of the color layer to be colored, and controls the application timing of the first pulse for preheating the color layer to be colored to match the application timing of at least the second pulse used for coloring a color layer other than the color layer to be colored.

12. 12. The recording apparatus according to claim 1, wherein a host device for outputting image data is included in the recording apparatus.

13. 13. The recording apparatus according to claim 1, wherein the pulse control means applies the first pulse and the second pulse to the same pixel.

14. A recording control method for a recording device having an input means for inputting image data from a host device, heating a sheet-like recording medium having a plurality of superposed color-forming layers, each of which corresponds to a plurality of colors and changes color in response to heating, by a recording head having a plurality of heating elements, thereby causing a desired color-forming layer among the plurality of color-forming layers to develop color and form an image on the recording medium, comprising: a control step of controlling at least one of lengthening a pulse width of the first pulse and increasing the number of times the second pulse is applied, so as not to cause other color layers not used for reproducing the specific color to develop color, when driving each of the plurality of heating elements of the recording head to develop a specific color using a first pulse for preheating a predetermined color layer and a second pulse applied after the first pulse for coloring the predetermined color layer, the recording medium is formed with a first coloring layer that develops a yellow (Y) color, a second coloring layer that develops a magenta (M) color, and a third coloring layer that develops a cyan (C) color, in that order from the side that contacts the plurality of heat generating elements of the recording head; driving the recording head based on image data input by the input means to cause the first color-forming layer, the second color-forming layer, and the third color-forming layer to develop colors in this order, thereby forming an image on the recording medium; A recording control method characterized in that the specific color is a color formed by coloring only the second color-forming layer, a color formed by coloring only the third color-forming layer, and a color formed by coloring both the second color-forming layer and the third color-forming layer.

15. A recording control method for a recording device, comprising the steps of: heating a sheet-shaped recording medium having a plurality of superposed color forming layers, the plurality of color forming layers corresponding to a plurality of colors and each coloring in response to heating, by a recording head having a plurality of heating elements, and causing a desired color forming layer among the plurality of color forming layers to develop color, thereby forming an image on the recording medium, the method comprising the steps of: a control step of controlling at least one of lengthening a pulse width of the first pulse and increasing the number of times the second pulse is applied, so as not to cause other color layers not used for reproducing the specific color to develop color, when driving each of the plurality of heating elements of the recording head to develop a specific color using a first pulse for preheating a predetermined color layer and a second pulse applied after the first pulse for coloring the predetermined color layer, The control step includes controlling the application timing of the first pulse so that preheating of the color layer to be colored is performed at the same timing as preheating of the color layer to be colored at an earlier timing, regardless of the color layer to be colored, and controlling the application timing of the first pulse for preheating the color layer to be colored to match the application timing of at least the second pulse used for coloring a color layer other than the color layer to be colored.

16. A recording device for forming an image on a sheet-like recording medium having a plurality of color-forming layers that correspond to a plurality of colors and that develop color in response to heating, by heating a desired color-forming layer among the plurality of color-forming layers to develop color, comprising: A recording head having a plurality of heating elements; a driving means for driving each of the plurality of heat generating elements of the recording head by using a first pulse for preheating a predetermined color forming layer and a second pulse for causing the predetermined color forming layer to color, the second pulse being applied after the first pulse; a conveying means for conveying the recording medium in a first direction relative to the recording head; a control means for controlling the driving means to use the first pulse for a first pixel located in an image non-forming area of ​​the recording medium, and to use the second pulse for a second pixel located in an image forming area of ​​the recording medium and recorded after the first pixel; the control means at least either changes a duty ratio of the first pulse used at the position of the first pixel or changes an application time of the first pulse, depending on whether the color-producing layer that produces color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer, based on image data; The recording device is characterized in that, when there are multiple desired color-forming layers, the control means reduces the duty ratio of the first pulse or shortens the application time of the first pulse in order to preheat a color-forming layer located deep inside.

17. the first pixel and the second pixel are consecutive pixels in the first direction, 17. The recording apparatus according to claim 16, wherein the second pixel is a pixel located at a position where an image can be formed first in the image forming area with respect to the first direction.

18. 18. A recording apparatus according to claim 16, wherein none of the plurality of color forming layers develops color at the position of the first pixel by driving the driving means using the first pulse.

19. 19. The recording apparatus according to claim 16, wherein the first pixel is a white pixel.

20. A recording device as described in any one of claims 16 to 18, characterized in that the control means changes the value of the first pixel to a value other than white based on the image data used to form an image in the second pixel, so as not to cause color to be produced in the multiple color layers.

21. 21. The recording apparatus according to claim 20, wherein the control means controls so as to perform preheating by the first pulse when a specific combination of a value of the second pixel and a value of the first pixel is found.

22. The method further includes acquiring a thermal history of the first pixel, 22. The recording apparatus according to claim 16, wherein the duty ratio of the first pulse is reduced or the application time of the first pulse is shortened based on the thermal history acquired by the acquisition means.

23. A recording control method for a recording device, comprising the steps of: heating a sheet-shaped recording medium having a plurality of superposed color forming layers, the plurality of color forming layers corresponding to a plurality of colors and each coloring in response to heating, by a recording head having a plurality of heating elements, and causing a desired color forming layer among the plurality of color forming layers to develop color, thereby forming an image on the recording medium, the method comprising the steps of: a first pulse for preheating a predetermined color-forming layer and a second pulse for causing the predetermined color-forming layer to color, the second pulse being applied after the first pulse, when driving each of the plurality of heat generating elements of the recording head; a control is performed so that the first pulse is used for a first pixel located in an image non-forming area of ​​the recording medium, and the second pulse is used for a second pixel located in an image forming area of ​​the recording medium and recorded after the first pixel; based on input image data, at least one of changing a duty ratio of the first pulse used at the position of the first pixel or changing an application time of the first pulse depending on whether the color-producing layer that produces color at the position of the second pixel is a first color-producing layer or a second color-producing layer different from the first color-producing layer; A recording control method characterized in that, when there are multiple desired color-forming layers, the duty ratio of the first pulse is reduced or the application time of the first pulse is shortened in order to preheat a color-forming layer located deep inside.

Images