JPH06198974A - Density gradation printing method and device - Google Patents

Abstract

PURPOSE:To optimally reproduce a wide range of density gradation by a method wherein a pixel has the same size and pixel elements of one pixel are arranged within an image in an array pattern most suitable for printing density data or the pixel element densities are made constant. CONSTITUTION:Based on a clock signal CK and a printing trigger TR, an printing timing control circuit 10 outputs a memory control timing signal MTG, a serial/parallel conversion timing signal CKSP, a data conversion timing signal LDTG and a resolution switching timing signal DPTG respectively to a memory control circuit 11, a serial/parallel conversion circuit 12, a data conversion circuit group 13, a laser control data switching circuit 14, and a resolution control circuit 15. The memory control circuit 11 outputs a MTC signal based on the MTG signal issued from the printing timing control circuit 10 to control an image memory 16. The image memory 16 where image data have been stored outputs the printing data to the serial/parallel conversion circuit 12 as serial printing data SDT.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (FIGS. 1 to 2) Action (FIGS. 1 to 2) Working Example (1) First Working Example (FIGS. 1 to 1) (FIG. 9) (2) Second embodiment (FIGS. 2 to 10) (3) Effect of embodiment (4) Other embodiment Effect of invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a density gradation printing method and a density gradation printing apparatus, and is suitable for application to a density gradation printing by a laser printer which prints one pixel with a plurality of laser beams. It is a thing.

[0003]

2. Description of the Related Art Conventionally, in the case of printing density gradation by a printer, there are a density modulation method for expressing continuous gradation by analog density modulation and a method for expressing continuous gradation by binary values of ON and OFF. Among them, the density modulation method is a method of expressing a halftone by always making a pixel area to be printed constant and continuously modulating the pixel density in an analog manner.

Further, as a method of expressing continuous gradation by two values of ON and OFF, there are a dither method and a density pattern method. In the dither method, N × M pixels form one matrix size, and N × M pixel printing dots are formed from the N × M pixel gradation data. That is, one print dot corresponds to one gradation data.

In the density pattern method, N × M printing dots are formed from the gradation data of one pixel. One matrix size is composed of N × M printing dots, and there are a dot type, a spiral type, and a Bayer type depending on the method of distributing the printing dots within the size. By adopting the same method for peripheral pixels by this distribution method, pseudo halftone is obtained.

[0006]

However, in the above-mentioned density modulation method, in order to realize analog density gradation control with stability and high reliability, the head structure section and the recording section such as recording paper are photographed. It is limited to a method that can perform rich halftone density printing, as typified by a system that applies technology and a sublimation type thermal transfer system. In particular, as the recording paper, it is necessary to use a printing paper or a receiving paper coated with PET (polyethylene terephthalate).

Further, the characteristics, performance and use conditions of heads and recording papers must meet strict requirements. Variations in head characteristics cause variations in printing energy,
Since variations in the sensitivity characteristics of recording papers result in print densities, if characteristic differences appear in these, there is a problem in that density unevenness occurs on the print screen and image quality is degraded.

Further, in the dither method and the density pattern method for expressing continuous gradation by binary values of ON and OFF, the gradation property is governed by the matrix size, and the number of gradations is inevitably determined by the matrix size, which is abundant. There is a problem that the matrix size must be increased in order to obtain a sufficient number of gradations for expressing halftones.

Further, in the dither method and the density pattern method, the resolution is also governed by the matrix size, and it is necessary to reduce the matrix size in order to obtain high resolution, which limits the number of gradations. Further, false contours are also generated, and there is a problem that high resolution and multi-gradation conflict with each other.

Therefore, if the matrix size is increased in order to express abundant halftones, the internal structure of each matrix size can be clearly discriminated when the printed image is observed from the clear viewing distance, so that the optimum intermediate size is obtained. There was a problem that printing could not be done.

By the way, as a device applied to a printer by outputting a plurality of light beams at constant pitch intervals,
There are LED heads and EL heads used in the exposure section of electrophotographic printers. With these heads, resolutions of up to 800 [DPI] can be obtained.

Further, as a printer for printing by heat mode recording instead of quantum mode recording such as LED head and EL head, there are a sublimation type thermal transfer printer and a fusion type thermal transfer printer. As the heat source of these printers,
Although a thermal head is used, the efficiency of conversion of driving power into heat energy is poor, so that the power supply circuit and the driving circuit become large.

Further, there is a printer using a single laser as an exposure light source, and in the case of a laser beam printer, a scanning optical system such as a polygon mirror is required to scan the laser beam, which increases the size and print speed. There was a limit. Particularly, a sublimation type thermal transfer printer using one laser takes a long time to print.

There is a printer using a multi-beam laser in which a plurality of single lasers are used and the laser beam lights thereof are made multiple on the exposure surface by using mirrors and lenses. In this method, there is a limit to the number of beams that can be converted into multiple beams, and there is a problem in that the mirrors and lenses are increased in size.

The conventional printer does not use a multi-laser in which the lasers are required and which are arranged in a pitch, and there is no device that can be used for both quantum mode recording and heat mode recording.

The present invention has been made in consideration of the above points, and when one pixel is composed of a plurality of pixel elements, the size of one pixel is limited to a size that is difficult to discriminate from the clear viewing distance, An object of the present invention is to propose a density gradation printing method and a density gradation printing apparatus that can optimally reproduce a wide variety of density gradations.

[0017]

In order to solve such a problem, in the present invention, in the density gradation printing method of the halftone printing printer device 1 in which one pixel is composed of a plurality of pixel elements, the printing density data DT is A predetermined data string L
Data processing means 16, 12, 13 for converting to DDR,
Based on the control from the data processing means 16, 12, 13, there is provided pixel element forming means 14, 18, 19 for forming respective pixel elements, and the data processing means 16, 1 are provided.
According to the processing of 2 and 13, the pixel element forming means 14 and 18,
19 implements the corresponding pixel element, and limits the size of one pixel formed by the pixel element within the range where the internal configuration is difficult to discriminate from the clear visual distance, and the size of one pixel is the same. The inner pixel elements are arranged in an optimum arrangement pattern for print density data.

Further, in the present invention, in the density gradation printing method of the halftone printing printer device 1 in which one pixel is composed of a plurality of pixel elements, data for converting the print density data DT into a predetermined data string LDDR. Processing means 16,
12 and 13, and pixel element forming means 14, 18 and 19 for forming respective pixel elements under the control of the data processing means 16, 12, 13 respectively, and the data processing means 16, 12, 13 are provided. According to the process of 1., the pixel element forming means 14, 18, and 19 embody corresponding pixel elements, and limit the size of one pixel formed by the pixel elements within a range in which it is difficult to determine the internal configuration from the clear viewing distance, The pixel element density is kept constant, and the size of one pixel is reproduced in the optimum shape for the print density data.

Further, in the present invention, in the density gradation printing method of the halftone printing printer device 1 in which one pixel is composed of a plurality of pixel elements, data for converting the print density data DT into a predetermined data string LDDR. Processing means 16,
12 and 13, and pixel element forming means 14, 18 and 19 for forming respective pixel elements under the control of the data processing means 16, 12, 13 respectively, and the data processing means 16, 12, 13 are provided. According to the process of 1., the pixel element forming means 14, 18, and 19 embody corresponding pixel elements, and limit the size of one pixel formed by the pixel elements within a range in which it is difficult to determine the internal configuration from the clear viewing distance, The pixel elements are arranged in a pixel shape of a predetermined size having a predetermined pixel element density that is optimum for print density data.

Further, in the present invention, in the density gradation printing method of the halftone printing printer device 1 in which one pixel is composed of a plurality of pixel elements, data for converting the print density data DT into a predetermined data string LDDR. Processing means 16,
12 and 13, and pixel element forming means 14, 18 and 19 for forming respective pixel elements under the control of the data processing means 16, 12, 13 respectively, and the data processing means 16, 12, 13 are provided. According to the process of 1., the pixel element forming means 14, 18, and 19 embody corresponding pixel elements, and limit the size of one pixel formed by the pixel elements within a range in which it is difficult to determine the internal configuration from the clear viewing distance, The size of one pixel is the same, and the pixel elements in the one pixel are arranged in an optimum arrangement pattern for print density data, or the pixel element density is made constant and the size of one pixel is optimum for print density data. Whether to reproduce the shape or arrange the pixel elements in a pixel shape of a predetermined size having a predetermined pixel element density that is optimum for the print density data is appropriately selected.

In the present invention, the size of one pixel is the same, and the pixel element in the one pixel is the print density data DT.
As the method of arranging with the optimum arrangement pattern for the above, the arrangement pattern of the distributed density pattern method was used. Further, in the present invention, the arrangement pattern of the concentrated density pattern method is used as a method of making the pixel element density constant and reproducing the size of one pixel in the optimum shape for the print density data DT.

Further, in the present invention, the pixel element forming means 14, 18, 19 are formed by controlling each pixel element in two steps of on and off according to the print density data DT. Further, in the present invention, the pixel element forming means 14, 18, and 19 make the pixel elements 0, 1 and 1 with respect to the maximum realized density of the pixel elements according to the print density data.
N, 2 / N, 3 / N, ..., N / N (N is a natural number) times the multi-step printing density is controlled and formed.

Further, in the present invention, the pixel element forming means 14, 18, 19 control the expression method most suitable for the print density data DT in two stages of on and off, or 0, 1 for the maximum realized density. / N, 2 / N, 3 / N, ..., N /
Whether or not to control the multi-step printing density of N (N is a natural number) times is appropriately selected. Further, in the present invention, the pixel element is realized by quantum mode recording or heat mode recording. Further, in the present invention, laser beam light exposure is used for quantum mode recording or heat mode recording.

Further, according to the present invention, in the density gradation printing apparatus 1 in which one pixel is reproduced by exposure of a photon beam having a plurality of Gaussian distribution output characteristics, desired print density data DT is predetermined data. Data processing means 16, 12, 13 for converting into the column LDDR, and optical quantum beam control means for selectively controlling the optical quantum beams for forming respective pixel elements based on the control from the data processing means 16, 12, 13. 14, 16 and 18 and the photon beam control means 14, 16 and 18 are driven by the control from the photon beam control means 14, 16 and 18 to produce pixel elements within one pixel, and a plurality of photon beams output are parallelized at constant pitch intervals. The optical quantum beam output means 19 is provided, and the optical quantum beam control means 14, 16, 18 are operated according to the processing of the data processing means 16, 12, 13. By controlling the photon beam output means 19, the corresponding pixel element is embodied, and the size of one pixel formed by the pixel element is set within the range where the internal configuration is difficult to discriminate from the clear viewing distance, and the optimum photon beam output is obtained. By adopting the selection method of the means 19 or the optimum output control method of the photon beam output means 19, the density gradation modulation and / or the area gradation modulation in one desired pixel are separately, simultaneously or selectively performed. In this way, a rich variety of density gradations can be reproduced optimally.

Further, in the present invention, a multi-beam laser that outputs a plurality of laser beam lights is applied as the optical quantum beam output means 19, and quantum mode recording or laser beam light heating mode is used in which the laser beam lights are used as quantum modes. The heat mode recording used as is used.

[0026]

According to the process of converting the print density data DT into the predetermined data string LDDR, the corresponding pixel element is embodied, and the size of one pixel formed by the pixel element is changed from the clear visual distance to the internal configuration. The size of one pixel is the same, and the pixel elements in one pixel are arranged in an arrangement pattern most suitable for the print density data DT, or the pixel element density is set to be constant, and the pixel element density is fixed. Print density data D
By reproducing in an optimum shape for T, arranging the pixel elements in a pixel shape of a predetermined size having a predetermined pixel element density optimum for the print density data DT, or by selecting each timely, Rich density gradation can be optimally reproduced.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) First Embodiment In FIG. 1, reference numeral 1 generally indicates a sublimation thermal transfer printer in which a density gradation printing method and a density gradation printing apparatus according to the present invention are applied to sublimation thermal transfer recording. In the case of this printer 1, a plurality of multi-semiconductor lasers 3, which are driven by a head control block 2 and are arranged side by side, are arranged close to each other at a required pitch. In the case of this embodiment, for example, a diameter of 50
Eleven consecutive [μm] pixels are arranged close to each other in the diameter direction.

A heat sink 4 is arranged in contact with each of the semiconductor lasers 3 so as to efficiently radiate heat and prevent the temperature of the semiconductor lasers 3 from rising above the rated value. The oscillation wavelength of the semiconductor laser 3 matches the absorption wavelength characteristic of the heat conversion layer 5B of the ink film 5.

The ink film 5 is a base film 5A,
It is composed of a heat conversion layer 5B and a sublimation dye ink layer (dye layer) 5C. This base film mainly contains a few (μ
m] thick PET (polyethylene terephthalate) is used. Further, in order to efficiently convert the oscillation light from the semiconductor laser 3 into heat, the heat conversion layer 5B is coated with a substance having a high absorptivity (for example, carbon particles) dispersed therein. Further, as the sublimation dye ink layer (dye layer) 5C, a thin layer in which a dye having a large heat diffusion function is mixed with an appropriate binder is applied to the base film 5A.

The image-receiving paper 6 is designed to efficiently capture the activated dye from the ink film 5, and is composed of an image-receiving paper substrate 6A and an image-receiving layer 6B. Image receiving layer 6B
In order to receive the dye activated by the sublimation dye ink layer (dye layer) 5C, a plastic material (for example, polyester resin) having good dyeability such as PET is used.
The image receiving paper substrate 6A is configured to hold the image receiving layer 6B. Further, the image receiving paper 6 has mechanical characteristics such as elasticity and electrical characteristics such as insulation resistance, and has high color rendering properties in terms of whiteness.

The image receiving paper 6 and the ink film 5 are in close contact with each other and are inserted between the platen 7 and the transparent plate 8 so that the thermal diffusion development of the dye can be efficiently transmitted. The transparent plate 8 is fixed, and the image receiving paper 6 and the ink film 5 are brought into close contact with each other by applying a constant static pressure from the platen 7 side as shown by an arrow a. The transparent plate 8 is transparent to the oscillated light from the semiconductor laser 3, and when the oscillated light passes through the transparent plate 8, energy loss is not generated or is selected as a material most unlikely to occur. .

In this way, in the case of the sublimation type thermal transfer printer 1, the head control block 2 controls the multi-semiconductor laser 3 in accordance with the print data to execute the thermal mode recording, whereby the print pattern corresponding to the print data is obtained. Can be transferred from the ink film 5 to the image receiving paper 6.

In this embodiment, the head control block 2 is constructed as shown in FIG. 2, and the print trigger TR and the clock signal CK from the outside are inputted to the print timing control circuit 10. The print timing control circuit 10 detects the print trigger TR and manages and controls the print operation.

Actually, the print timing control circuit 10 is based on the input clock signal CK and the print trigger TR, and is based on the memory control circuit 11, serial / parallel conversion circuit 12, data conversion circuit group 13, laser control data switching circuit 14. And a memory control timing signal MTG, a serial / parallel conversion clock signal CKSP, a data conversion timing signal DCNT, a laser oscillation timing signal LDTG, and a resolution switching timing signal DPTG.

The memory control circuit 11 controls the image memory 16 based on the memory control timing signal MTG from the print timing control circuit 10.
Is output. The print data is stored in the image memory 16, and the print data is converted into the serial print data S based on the memory control signal MCT from the memory control circuit 11.
It is output to the serial / parallel conversion circuit 12 as DT.

The resolution control circuit 15 switches the character / natural image signal MP input from the outside at an appropriate timing depending on the type of print data. In practice, the print mode information PT from the print mode control circuit 17
MD, a character / natural image signal MP from the outside, and a resolution switching timing signal DP from the print timing control circuit 10.
Resolution information D that changes only in the section permitted by TG
The PDT is output to the data conversion circuit group 13 and the laser control data switching circuit 14.

The print mode control circuit 17 outputs a modulation mode selection signal MD input from the outside to the data conversion circuit group 13, the laser control data switching circuit 14 and the resolution control circuit 15 as print mode information PTMD. As the print mode information PTMD, density gradation modulation, area gradation modulation, area gradation modulation accompanied by density modulation, density gradation modulation and area gradation modulation are selectively adopted, and laser control is performed on / off. There are laser control with a plurality of current values, on / off of laser control and selective control of a plurality of current values.

The serial / parallel conversion circuit 12 performs serial / parallel conversion of the serial print data SDT from the image memory 16 in accordance with the serial / parallel conversion clock signal CKSP from the print timing control circuit 10 and parallels it to the data conversion circuit group 13. The converted print data DT is output.

The data conversion circuit group 13 converts the parallel digital print data DT from the serial / parallel conversion circuit 12 into print mode information PTMD from the print mode control circuit 17 and resolution information D from the resolution control circuit 15.
The data conversion method is determined according to the PDT, and the data conversion timing signal DCN from the print timing control circuit 10 is determined.
It is converted into laser control data LDDR at a timing according to T. The data conversion circuit group 13 is configured by combining circuits for the number of parallelized print data DT, and outputs the laser control data LDDR to the laser control data switching circuit 14.

Laser control data switching circuit 14
Is the laser control data LD from the data conversion circuit group 13.
DR is the print mode information PTMD from the print mode control circuit 17 and the resolution information DPD from the resolution control circuit 15.
The connection route is selected according to T, the laser oscillation signal LDR is converted at a timing according to the data conversion timing signal LDTG from the print timing control circuit 10, and this is output to the laser driver group 18.

The laser driver group 18 sends the drive signal DRV to the semiconductor laser 19 based on the laser oscillation signal LDR from the laser control data switching circuit 14 to drive the semiconductor laser 19 for light emission. It is composed of a circuit. Further, the light intensity signal SAP from the photo detector 20 corresponding to the driven semiconductor laser 19
By C, the oscillation light intensity of the semiconductor laser 19 is controlled to be constant.

In the above configuration, for example, the timing of laser oscillation is expressed as shown in FIG. That is, when the print data is already stored in the image memory 16 and the print trigger TR is input from the outside, the print timing control circuit 10 starts the head control. The memory control circuit 11 controls the image memory 16 so that the print data inside the image is converted into the serial print data SDT (see FIG. 3).
(A)) are sequentially read.

The serial / parallel conversion circuit 12 sequentially converts the serial print data SDT into parallel print data DT (FIG. 3 (C)) in accordance with the serial / parallel conversion clock signal CKSP (FIG. 3 (B)). The data conversion circuit group 13 converts the respective parallel print data DT into data conversion timing signals DCNT (see FIG. 3 (D) according to the number of lasers per pixel and the driving method designated by the print mode information PTMD and the resolution information DPDT. )) Is converted into oscillation information corresponding to each laser at the prescribed timing and output as laser control data LDDR (FIG. 3 (E)).

Laser control data switching circuit 14
Is the laser oscillation timing signal LDTG (FIG. 3 (F))
According to the drive start method specified by the print mode information PTMD and the resolution information DPDT, the timing of actually oscillating the laser and the laser oscillation signal LDR corresponding to the laser element (see FIG. 3). (G) to FIG. 3 (M)) are output.

Under the control of this laser oscillation signal LDDR, the laser driver group 18 drives the corresponding laser 19. The photodetector 20 detects a part of the corresponding laser light and causes the laser driver 18 to feed back the laser light so that the laser oscillation is stably maintained.

By oscillating each laser 19 in a manner and timing suitable for printing as described above, the oscillated light emitted from the semiconductor laser 3 (FIG. 1) passes through the transparent plate 8 and is heated by the base film 5A. Reach conversion layer 5B.
At this time, the transparent plate 8 and the base film 5A are selected so as not to absorb the laser oscillation light wavelength or negligible even if it absorbs it, and the laser oscillation light almost reaches the heat conversion layer 5B.

Since most of the laser oscillation light is absorbed in the heat conversion layer 5B, the laser oscillation light is converted into heat here. The heat generated here heats and activates the dye in the sublimation dye ink layer (dye layer) 5C, and the heat is diffused to the image receiving layer 6B on the image receiving paper 6 which is pressure-bonded. Therefore, the dye in the sublimation dye ink layer (dye layer) 5C is transferred to the image receiving layer 6B on the image receiving paper 6 at the portion heated by the semiconductor laser 3. The dye received in the image receiving layer 6B is stabilized and becomes a visible image.

When printing a halftone in the sublimation type thermal transfer printer 1 as described above, the size of one pixel is set to 50 [μm], and the pixel elements therein are arranged in an optimum arrangement pattern. When the printed image is viewed from the clear viewing distance, the density gradation modulation as shown in FIG. 4 is performed, whereby the halftone can be printed. Note that this distinct viewing distance is based on the characteristics of the human visual system.
It can be specified to a distance of 30 [cm] to 40 [cm].

Further, by making the pixel element density constant and changing the size of one pixel, and further setting the maximum size to 50 [μm], area gradation modulation becomes possible, and the printed image can be obtained from the clear viewing distance. When viewed, as shown in FIG. 5, it becomes difficult to recognize the difference in size, and halftone can be printed.
Further, by combining these density gradation modulation and area gradation modulation to change the pixel element density and the pixel diameter,
Also, as shown in FIG. 7, density gradation and area gradation modulation can be realized, and halftone can be printed.

Further, by combining the density gradation modulation, the area gradation modulation, the density gradation and the area gradation modulation, as shown in FIG. 8, the area gradation modulation of 1000 [DPI] is performed at the time of character printing. During natural image printing, density gradation modulation of 500 [DPI] or density gradation and area gradation modulation can be realized, and halftone can be printed.

Further, the laser drive is controlled in two stages of on and off, and as shown in FIG. 9, the laser drive is 0, 1/3 × Lmax, 2/3 × Lma of the continuous oscillation maximum value (Lmax).
It is possible to print halftones by controlling in four steps of x and Lmax. However, the light intensity of the continuous oscillation maximum value is the intensity that becomes the maximum density pixel element at the time of printing, and within this light intensity variable range (1/3 to 1), the corresponding pixel element density also changes correspondingly. .

According to the above configuration, the corresponding pixel element is embodied according to the process of converting the print density data into a predetermined data string, and the size of one pixel formed by the pixel element is clearly visible. Limit the distance to the range where the internal configuration is difficult to discriminate, and the size of one pixel is the same. Reproduce the size of one pixel in an optimum shape for the print density data, or arrange the pixel elements in a pixel shape of a predetermined size having a predetermined pixel element density optimum for the print density data. By making the selection, rich density gradation can be optimally reproduced.

(2) Second Embodiment In FIG. 10 in which parts corresponding to those in FIG. 1 are designated by the same reference numerals, reference numeral 21 indicates, as a whole, a density gradation printing method and a density gradation printing apparatus according to the present invention, which are fusion-type thermal transfer. A fusion type thermal transfer printer applied to recording is shown, and in the case of this printer 21, the ink film 22 is a base film 22A, a heat conversion layer 2
2B and the hot melt ink layer 22C.

The base film 22A mainly has a number [μm].
Use thick PET. In order to efficiently exchange the oscillation light from the semiconductor laser 3 with heat, the heat conversion layer 22B is coated with a substance having a high absorptivity such as carbon particles dispersed therein. The hot-melt ink layer 22C is formed by mixing and dispersing pigments, dyes, binders and the like in wax or resin as a base. Further, the recording paper 23 is the melted ink 22.
The material is selected so that B can be reliably transferred, and high-quality paper, so-called plain paper is usually used.

In this printer 21, when the semiconductor laser 3 is oscillated with the method and timing suitable for printing as described above with reference to FIG. 3, the oscillated light output from the semiconductor laser 3 passes through the transparent plate 8 and Film 22
It reaches the heat conversion layer 22B through A. At this time, the transparent plate 8 and the base film 22A are selected so as not to absorb the laser oscillation light wavelength or negligible even if it absorbs the laser oscillation light, and the laser oscillation light almost reaches the heat conversion layer 22B.

Since most of the laser oscillation light is absorbed in the heat conversion layer 22B, the laser oscillation light is converted into heat here. The heat generated here is the hot-melt ink layer 22.
The hot-melt ink C is heated and melted and brought into contact with the recording paper 23. Subsequently, when the ink film 22 and the recording paper 23 are separated, the thermally melted ink layer melted by the laser oscillation light is transferred to the recording paper 23 side as the remaining transfer ink 24. Further, the heat-melted ink layer 22C not irradiated with the laser oscillation light remains on the ink film 22 side.

Even in such a fusion type thermal transfer printer 21, by controlling as shown in FIGS. 4 to 9, halftones can be printed in the same manner as the sublimation type thermal transfer printer 1 described above.

(3) Effect of the Embodiment In the printer device, when selecting the photon beam output means, one pixel has the same size and the pixel elements therein are arranged in the optimum pattern or the pixel element density is constant. Then 1
Either the pixel size is reproduced in an optimum shape, or these are combined to arrange the pixel elements in a pixel shape having an optimum pixel element density, or a combination thereof is selected as needed.

In addition to this, the output control of the optical quantized beam output means is controlled in two stages of on / off, multistage printing density control as necessary, or a combination of these, and when necessary, timely. select.

As a result, when the density of each pixel is made uniform at about 50 [μm] and density gradation modulation is performed by changing the pixel element density, the clear visual distance (30 [cm] to 40 [cm] from the recording paper)
From the perspective, the change in the pixel element density itself cannot be recognized, but the pixel itself can be recognized as providing the density change.

Incidentally, in the naked eye characteristic, when observing the recording and printing from the clear visual distance, it is said that a pixel having a diameter of 80 [μm] to 100 [μm] or less cannot recognize the difference in diameter.
Therefore, in the case of the embodiment, by defining the diameter of each pixel to be smaller than 80 [μm] and a diameter of about 50 [μm],
It can be revisited as density gradation modulation.

Further, by keeping the pixel element density constant and changing the size of each pixel within about 50 [μm], area gradation modulation can be performed, and the difference in size can be detected from the clear viewing distance. Will be difficult to do.

Further, by simultaneously controlling the density gradation modulation and the area gradation modulation, the area modulation accompanied by the density modulation can be realized and a wide multi-gradation printing can be performed. By combining them in a timely manner so as to be suitable for a pattern (for example, character printing, natural image, etc.), it is possible to adopt an optimal printing method and printing resolution for each printing pattern.

Generally, it is said that it is sufficient to print with a line number of 1000 [DPI] for character printing and 500 [DPI] or more for natural images. Therefore, according to the method of this embodiment, printing within one page is possible. However, if some part is printed with characters 1000 [DPI]
However, when another part is used for natural image printing, printing with a line number of 500 [DPI] can be used to realize optimum printing for both.

According to the above construction, desired density gradation modulation within one pixel can be realized, area gradation modulation can be realized, and density gradation modulation and area gradation modulation can be performed simultaneously or selectively. It is possible to realize a printer that can realize a wide variety of gradations.

Further, according to the above configuration, when each pixel element is realized by exposure of a multi-laser which is one-dimensionally arranged in parallel at a constant pitch interval to generate a laser beam light having a Gaussian distribution output characteristic corresponding to each pixel element, As for laser control, when the desired print density is low, the laser drive power can be kept low, there is no need to constantly oscillate at the maximum laser drive power, and low output oscillation is sufficient, so less heat is generated The life of the device can be extended.

Further, according to the above-mentioned structure, the heat generation due to the oscillation of the laser is small, so that the output fluctuation due to the heat of the laser itself becomes small and the control can be performed with high accuracy. Along with this, thermal interference between multiple lasers is reduced, and when oscillating multiple lasers, mutual influences are reduced,
Each can be controlled with high accuracy, and the correction by the neighboring laser is reduced.

Further, according to the above configuration, since one pixel is formed by exposure of a plurality of laser beam lights, the characteristic difference of individual laser beam light is canceled, and printing is performed on the whole pixel due to the characteristic difference of laser beam light. Variation can be reduced.

Further, according to the above configuration, if this halftone printing method is realized by exposure of a single laser beam, a large number of scan times are required, but one scan corresponds to a plurality of pixel elements. Exposure is performed, and the printing speed of one pixel is significantly increased. Further, by using a plurality of sets of multi-lasers forming one pixel, a large number of pixels can be printed with a single scan, and the printing speed can be greatly improved.

(4) Other Embodiments In the above-described embodiments, the present invention is applied to the laser printer for thermal transfer recording, but the present invention is not limited to this, and may be applied to a printer for thermal transfer recording using a thermal head. Also, the same effect as that of the above-described embodiment can be realized.

In the above embodiment, the multi-laser light of the laser printer was used in the heat mode, but instead of this, the multi-laser light is used in the quantum mode to form a latent image on the photoconductor by the electrophotographic method. Even if it is used for the means, the same effect as that of the above-mentioned embodiment can be realized.

Further, although the present invention is applied to the laser printer in the above-described embodiments, the present invention is not limited to this, and as the quantum mode recording, the LED head of the LED printer, the liquid crystal head of the liquid crystal printer or the EL head of the printer using the EL head is used.
It can also be applied to a head or the like.

[0074]

As described above, according to the present invention, according to the process of converting the print density data into a predetermined data string, the corresponding pixel element is embodied, and one pixel constituted by the pixel element is realized. The size is limited to a range in which the internal configuration is difficult to discriminate from the clear visual distance, and the size of one pixel is the same. The element density is kept constant, and the size of one pixel is reproduced in the optimum shape for the print density data, or the pixel elements are arranged in the pixel shape of the predetermined size having the predetermined pixel element density optimum for the print density data. Alternatively, abundant density gradations can be optimally reproduced by selecting each timely.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a sublimation type thermal transfer printer to which a density gradation printing method and a density gradation printing device according to the present invention are applied.

FIG. 2 is a block diagram showing a circuit configuration of a head control block of the sublimation type thermal transfer printer of FIG.

FIG. 3 is a timing chart for explaining the operation of the head control block shown in FIG.

FIG. 4 is a schematic diagram showing a printing result by density gradation modulation as a printing example according to the present invention.

FIG. 5 is a schematic diagram showing a printing result by area gradation modulation as a printing example according to the present invention.

FIG. 6 is a schematic diagram showing a printing result by a combination of density gradation modulation and area gradation modulation as a printing example according to the present invention.

FIG. 7 is a schematic diagram showing a printing result by a combination of density gradation modulation and area gradation modulation as a printing example according to the present invention.

FIG. 8 is a schematic diagram showing a print result of mixed characters and natural images as a print example according to the present invention.

FIG. 9 is a characteristic curve diagram showing a relationship between a laser drive current and a light output for controlling the laser light output.

FIG. 10 is a schematic diagram showing an embodiment of a fusion type thermal transfer printer to which the density gradation printing method and the density gradation printing device according to the present invention are applied.

[Explanation of symbols]

1, 21 ... Printer, 2 ... Head control block, 3
...... Multi-semiconductor laser, 4 ... Heat sink, 5,2
2 ... Ink film, 6 ... Image receiving paper, 7 ... Platen, 10 ... Print timing control circuit, 11 ... Memory control circuit, 12 ... Serial-parallel conversion circuit, 13 ...
... data conversion circuit, 14 ... laser control data switching circuit, 15 ... resolution control circuit, 16 ... image memory, 17 ... print mode control circuit, 18 ... laser driver, 19 ... laser, 20 ... Photo detector, 2
3 ... Recording paper.

Claims (13)

[Claims] 1. A data processing means for converting print density data into a predetermined data string in a density gradation printing method of a halftone printing printer device in which one pixel is composed of a plurality of pixel elements, and the data processing. A pixel element forming unit that forms each of the pixel elements under the control of the unit, and implements the corresponding pixel element by the pixel element forming unit according to the process of the data processing unit. The size of one pixel composed of elements is limited to a range in which the internal configuration is difficult to discriminate from the clear visual distance, and the size of one pixel is the same, and the pixel element in the one pixel is used as the print density data. A density gradation printing method characterized by arranging with an optimum arrangement pattern. 2. A data processing means for converting print density data into a predetermined data string in a density gradation printing method of a halftone printing printer device in which one pixel is composed of a plurality of pixel elements, and the data processing. A pixel element forming unit that forms each of the pixel elements under the control of the unit, and implements the corresponding pixel element by the pixel element forming unit according to the process of the data processing unit. The size of one pixel made up of elements is limited to the range where the internal configuration is difficult to distinguish from the clear visual distance, the pixel element density is kept constant, and the size of one pixel is reproduced in an optimum shape for the print density data. A density gradation printing method characterized in that 3. A data processing means for converting print density data into a predetermined data sequence in a density gradation printing method of a halftone printing printer device in which one pixel is composed of a plurality of pixel elements, and the data processing. A pixel element forming unit that forms each of the pixel elements under the control of the unit, and implements the corresponding pixel element by the pixel element forming unit according to the process of the data processing unit. The size of one pixel composed of elements is limited to a range in which the internal configuration is difficult to distinguish from the clear visual distance, and the pixel element is a pixel of a predetermined size having a predetermined pixel element density optimum for the print density data. A density gradation printing method characterized by being arranged in a shape. 4. A data processing means for converting print density data into a predetermined data string in a density gradation printing method of a halftone printing printer device in which one pixel is composed of a plurality of pixel elements, and the data processing. A pixel element forming unit that forms each of the pixel elements under the control of the unit, and implements the corresponding pixel element by the pixel element forming unit according to the process of the data processing unit. The size of one pixel composed of elements is limited to a range in which the internal configuration is difficult to discriminate from the clear visual distance, and the size of one pixel is the same, and the pixel element in the one pixel is used as the print density data. Whether to arrange in an optimum arrangement pattern, or to make the pixel element density constant and reproduce the size of one pixel in an optimum shape for the print density data,
Alternatively, the density gradation printing method is characterized in that it is timely selected whether or not the pixel elements are arranged in the pixel shape of a predetermined size having the predetermined pixel element density optimal for the print density data. . 5. The arrangement pattern of the dispersed density pattern method is used as a method for arranging the pixel elements in the 1 pixel in the same arrangement pattern as the print density data, since the 1 pixel has the same size. 5. The density gradation printing method according to claim 1, claim 3 or claim 4, wherein: 6. An arrangement pattern of a centralized density pattern method is used as a method of making the pixel element density constant and reproducing the size of one pixel in an optimum shape for the print density data. The density gradation printing method according to claim 2, claim 3, or claim 4. 7. The pixel element forming means controls and forms each of the pixel elements in two stages of on and off according to the print density data. The density gradation printing method described in. 8. The pixel element forming means sets each of the pixel elements to 0, 1 / N, 2 / N, 3 / N, ... With respect to the maximum realized density of the pixel element according to the print density data.
The density gradation printing method according to any one of claims 1 to 6, wherein the multi-step printing density is controlled to be N / N (N is a natural number) times. 9. The pixel element forming means controls an expression method most suitable for the print density data in two stages of on and off, or 0, 1 / N, 2 / N, 3 for the maximum realized density.
/ N, ..., N / N (N is a natural number) times the multi-step printing density is controlled to be properly selected. Method. 10. The density gradation printing method according to claim 1, wherein the pixel element is realized by quantum mode recording or heat mode recording. 11. The density gradation printing method according to claim 10, wherein exposure of a laser beam is used for the quantum mode recording or the heat mode recording. 12. A data processing for converting desired print density data into a predetermined data string in a density gradation printing apparatus in which one pixel is reproduced by exposure of a photon beam having a plurality of Gaussian distribution output characteristics. Means, and a photon beam control means for selectively controlling the photon beam that creates each pixel element based on the control from the data processing means, and the control from the photon beam control means A photon beam output means that is driven to create the pixel element of, and that outputs a plurality of photon beam parallelized at a constant pitch interval. By controlling the photon beam output means, the corresponding pixel element is embodied, and the size of the one pixel constituted by the pixel element is By setting the internal configuration within a range that is difficult to discriminate from the viewing distance and adopting the optimum selection method of the photon beam output means or the optimum output control method of the photon beam output means, A density gradation printing apparatus characterized in that density gradation modulation and / or area gradation modulation are realized separately, simultaneously or selectively to optimally reproduce abundant density gradations. 13. A multi-beam laser that outputs a plurality of laser beam lights is applied as the optical quantum beam output means, and quantum mode recording using the laser beam lights as a quantum mode or using the laser beam lights as a heat mode. 13. The density gradation printing apparatus according to claim 12, wherein heat mode recording is used.