JP2002240338A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal printer which can obtain a visually smooth density curve for densities from a gradation 0 to a gradation 16 (a first representative point, an (a) gradation) which were considered impossible to linearly color because of heating characteristics of a thermal head and transfer characteristics of a recording ribbon. SOLUTION: In the thermal printer, photoprinting is carried out by a thermal sublimation system by predetermined energization to the thermal head while a color layer of each color butted on a recording sheet material is moved. A plurality of gradation data are read into the thermal printer, and the predetermined energization is set to zero not to color at the gradation 0 among a plurality of the read gradation data. There is set an energization curve for correcting an energization time before a coloring start by the thermal head so as to color the density up to the gradation 1 specified first.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

2. Description of the Related Art In a thermal printer that performs printing by thermal sublimation or thermal transfer recording, for example, using a recording ribbon of Y (yellow), M (magenta), and C (cyan), which are three primary colors of additive color mixture, 256 colors are used. When performing gradation printing, the energizing time to the thermal head, which is the applied energy corresponding to each of the 16 points, is set at the time of gradation design, for example, with 16 points for every 16 gradations as representative points.
Then, the energizing time is proportionally distributed between the respective gradations.

FIG. 6 is a diagram showing a conventional relationship between 256 gradations and density. FIG. 7 is a correlation diagram showing the coloring characteristics up to a density of 0.08 in FIG.

First, in FIG. 6, when gradation is designed for gradation expression of 256 gradation input of print data sent from the outside, the density curve shown in FIG. The power supply time to the thermal head is set with 1 being ideal. The energization time is simply proportionally distributed between the representative points. In this way, by proportionally distributing the energy applied to the thermal head between the representative points, the density between the representative points is also approximately proportionally distributed.

[0004]

However, when the applied energy is between zero and the first representative point a, the relationship between the applied energy and the color density is linear due to the heat generation characteristics of the thermal head and the transfer characteristics of the recording ribbon. It is known that, as shown in FIG. 7, the color development does not start until the gradation input data k becomes “10” and the density curve actually becomes 2.

That is, as shown in FIG. 6, if the current supply time is simply proportionally divided by dividing the first representative point up to 16 gradations into 16 equal parts, the energy applied to the thermal head can be changed from zero to 16 gradations. During this period, it is known that the applied energy and the color density are not proportional and the color development cannot be controlled. In addition, since the color is suddenly colored in the vicinity of "16" of the gradation input data, a white background on the recording surface of the recording sheet suddenly develops a color in gradation reproduction, and particularly the highlight portion is unnatural. Becomes

As a countermeasure, a thermal head is preliminarily heated (preheated) corresponding to an unprinted portion so that the start of color development is accelerated. Also, JP-A-11-7810
Japanese Patent Laid-Open No. 1-2005-175 discloses a technique for accurately examining the heat storage state of a thermal head and accurately correcting the density fluctuation due to the heat storage.

Further, Japanese Patent Application Laid-Open No. 9-58041 discloses that printing is performed at a density different from normal by changing the conduction width determined from the resistance value rank of the heat generating portion of the thermal head and the measured temperature rank by a simple operation. Is disclosed.

However, if the thermal head is subjected to the residual heat as described above, the recording head is fogged due to the fluctuation of the recording ribbon or recording sheet material, the individual difference of the thermal printer, etc. ) Is a problem.

Further, according to the above publications, there is no mention of smoothing the density between the 0th gradation and the 16th gradation (first representative point a).

Therefore, the present invention has been made in view of the above-mentioned problems, and it is not possible to form a color linearly from the 0th gradation to the 16th gradation from the relationship between the heat generation characteristic of the thermal head and the transfer characteristic of the recording ribbon. It is an object of the present invention to provide a thermal printer capable of visually providing a smooth density curve for the density up to the key (first representative point a).

In addition, another object of the present invention is to provide a thermal printer capable of coping with individual differences of the thermal printer and capable of individually performing fine adjustment in response to fluctuations of the recording ribbon or sheet material.

[0012]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, according to the present invention, the recording ribbon on which each color layer is laid is held against a heat generating portion of a thermal head, and the color ribbons are moved while being in contact with a recording sheet material. In a thermal printer which performs printing by thermal sublimation or thermal transfer recording by a predetermined energization of the thermal head, a gray scale data input means for reading a plurality of gray scale data; With regard to the above, in order to make the predetermined energization zero and to make the color non-coloring, and to make it possible to develop the density of one gradation defined first from the non-coloring, the energization time until the start of color development by the thermal head is corrected And a correcting means for the purpose.

When the plurality of gradation data are divided by M representative points, the correction means sets the representative point having the lowest density value to the a-th gradation and sets o [k] to the lowest density. When the conduction time of the k-th gradation data up to the representative point a of the value is set and Y is an integer, 0 <k <a, 0 <Y <a, and o [0] = 0 (input 0 O [k] = o [a] × (Y / a + (1−Y / a) × (k /
a) setting the integer and determining the energizing time based on the arithmetic expression a)).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of gradation data 256, which is a preferred embodiment of the present invention, is divided into 16 representative points, and the first representative point is set to 16 gradations. This will be described with reference to the drawings.

FIG. 1 is a block diagram of a thermal printer. In this figure, there are various types of mechanism configurations of the thermal printer. As shown in the drawing, the transport speed of the sheet material P and the transport speed of the recording ribbon R are determined by using a recording ribbon R wound in a ribbon cartridge (not shown). A thermal printer configured to perform thermal sublimation recording or thermal transfer recording at the same transport speed will be described as a representative.

On the recording ribbon R, each of the three primary color layers Y,
M and C are sequentially formed in accordance with the area of the recording surface of the sheet material P, and are conveyed in the direction of the arrow to wind the used recording ribbon R in the ribbon cartridge and to the heating section 41 of the thermal head 40. Is configured to perform thermal sublimation recording by applying a current.

The driver unit 31 connected to receive power supply from the power supply unit 33 for performing predetermined power supply to the heating unit 41 is connected to the control unit 30. Control unit 30
Is connected to the interface section 32, and receives γ gradation data sent from the outside. The control unit 3
0 is connected to a storage unit 33 in which an energization time table corresponding to γ gradation data is stored in advance.

FIG. 2 is a flowchart showing the steps up to the data conversion processing of the γ gradation data in the above configuration.

Referring to FIG. 1, in step S1, a γ gradation data file is read. Subsequently, step S2
Then, the conversion parameter is determined from the power-on time table corresponding to the γ gradation data. After this, step S
In step 3, a data conversion process is performed to prepare for a predetermined energization of the thermal head.

FIG. 3 is a flowchart of a data conversion processing routine program in step S3 of FIG. In FIG. 3, in step S10, the energizing time, which is the applied energy of the thermal head, is set to “zero” for the 0-gradation among the 256 gradations, which is the non-printing area, for example. Also, the Y value is set in the range of 1 to 15 (a-1). By setting the Y value, the energizing time is set to the first gradation from the non-printing (density zero) where the energizing time is zero to the 16th (a) gray scale out of 256 tones as the first representative point. Set as desired. Here, for the 0th gradation, the energization time is zero, so that it is possible to avoid background fogging (a phenomenon in which a portion that should originally be a non-printed image is colored).

Next, in step S11, it is determined whether or not the gradation k is equal to or less than 16 (a) gradation, and the output value o [corresponding to the input gradation data 0 to 16 (a) is determined. 0] ~
Conversion is performed on o [15 (a-1)] (applied energy). In step S11, the gradation k is 16
(A) When it is determined that the current value is equal to or higher than the gradation, the conversion parameter in step S2 is determined as the conduction time o [k] as the output value from the conduction time table corresponding to the γ gradation data.

In step S11, the gradation k is 16
(A) If it is determined that the tone is lower than the gradation, step S13
And proceed to o [k] = o [a] × (Y / a + (1-Y / a) ×
(K / a)) from the energization time o [0] which is the output value to [a
-1], then proceeds to step S14, adds 1 to k, returns to step S11, and repeats until the gradation k becomes equal to or more than a.

As described above, when the Y value is 1, 2, 3,
.., 15 (a-1) can be set from the operation panel so that, in the energization curve diagram shown in FIG. The energization time can be set arbitrarily.

That is, conventionally, no color was developed as a result of simple plotting on a niria line along the ideal curve 1 described in FIG. 6, but for example, plotting from a curve 11 obtained by setting the Y value to 7 Contains the gradation input data k
Is 1, the energization time is 800 microseconds, so that color development is possible.

For example, if the Y value is 8, 9, 10, 11,
The energization curve 12, which is obtained by setting to 12, 13, and 14,
13, 14, 15, 16, 17, and 18, when the gradation input data k is 1, the energizing time is set to 900, 1150, 1250, 1350, 140
Since it can be appropriately set to 0, 1550 microseconds, it is possible to cope with individual differences of the thermal printer, and it is possible to individually make fine adjustments in response to fluctuations of the recording ribbon or sheet material.

FIG. 5 shows the current distribution curves 12, 13 and
Density curves 21, 22, 23, 24, 2 according to the energizing time plotted from 14, 15, 16, 17, and 18, respectively.
FIG. 6 is a relationship diagram of 5, 26, 27, and 28 and gradation data 1 to 16 (a).

In FIG. 5, in the conventional actual density curve 2 described with reference to FIG. 6, coloring is started only when the gradation k reaches 10, but according to the density curve 21 based on the energization curve 12, for example, When the gradation data k is 5, color development can be started, and when the gradation data k is 7, the visible density can be set to 0.01.

The density curve 2 based on the energization curve 18
According to No. 8, it was confirmed that coloring can be started when the gradation data k is 1, and the density can be set to 0.055, which is sufficiently visible.

As described above, since the energization time can be set appropriately, it is possible to cope with individual differences of the thermal printer, and to make individual fine adjustments in accordance with the fluctuation of the recording ribbon or sheet material.

Although discretely set in units of 1/16 (1 / a) as described above, it may be continuously variable as follows.

That is, o [a]: as an output (applied energy) corresponding to the input gradation data a as the first representative point, the value of x is in the range of 0 ≦ x ≦ 1, and is individually obtained from the operation panel or the like. By making it adjustable, o [k]
= O [a] × (x + (1-x) × (k / a)).

As described above, since the applied energy is always 0 for the 0th gradation, the background fogging (a phenomenon in which a portion which should originally be a non-printed portion develops a color) can be avoided. The energization time is the color development point 1100
Since no color was formed up to the input data (10th gradation) reaching ms, the information corresponding to the input data 0 to 10 was lost from the print, but as described above, the color was formed from the first gradation. Can be started, so that information corresponding to the gradation input data 0 to 10 which has been completely lost in the past can be reproduced. Further, since heating is not performed on the non-printed portion, the ground fogging does not occur.

The present invention is not limited to the embodiments described below, but can have various configurations defined in the claims. For example, the present invention is applicable to the gradation expression of print data sent from the outside. The gradation of 256 gradation widths is 16 for every 16 gradations.
Although the case where a point is set as a representative point has been described, the gradation is 256
It may be greater than or equal to or less than 256. Further, the value of a described above can also be variously set according to the requirements at the time of gradation design.

[0033]

As described above, according to the present invention,
The density from 0 to 16 (the first representative point, the a-th tone), which is considered to be incapable of linear color development due to the heat generation characteristics of the thermal head, is visually visually smooth. A thermal printer capable of obtaining a curve can be provided.

In addition, it is possible to provide a thermal printer capable of coping with individual differences of thermal printers and capable of individually performing fine adjustment in response to fluctuations of a recording ribbon or sheet material.

[Brief description of the drawings]

FIG. 1 is a block diagram of a thermal printer.

FIG. 2 is a flowchart showing steps up to data conversion processing of γ gradation data.

FIG. 3 is a flowchart of a data conversion processing routine program in step S4 of FIG. 2;

FIG. 4 is an energization curve diagram.

FIG. 5 is a density curve diagram.

FIG. 6 is a conventional density curve diagram.

FIG. 7 is a density curve diagram up to conventional gradation input data 16;

[Explanation of symbols]

1 ideal density curve 2 actual density curve 11, 12, 13, 14, 15, 16, 17, 18 energization curve 21, 22, 23, 24, 25, 26, 27, 28 density curve 40 thermal head 30 control unit R recording Ribbon k gradation input data

Continued on the front page (72) Inventor Masaharu Oguri 1 Sakuracho, Hino-shi, Tokyo Konica Corporation In-house F-term (reference) 2C066 AA03 AB09 AD01 AD03 CD03 CD04 CD07 CD12 CD14 CD27 CZ11 DA07

Claims (2)

[Claims] 1. A recording ribbon on which a color layer of each color is laid is held against a heat generating portion of a thermal head, and the respective color layers are moved while being in contact with a recording sheet material by a predetermined power supply to the thermal head. In a thermal printer that performs printing by thermal sublimation or thermal transfer recording, a gradation data input unit that reads a plurality of gradation data; and, among the read gradation data, the predetermined energization is zero for 0 gradation. Correction means for correcting the energization time until the start of color development by the thermal head in order to make the color non-colored and to enable the color development of one gradation defined first from the non-colored color. A thermal printer. 2. When the plurality of gradation data is divided by M representative points, the correction means sets a representative point having the lowest density value to an a-th gradation and sets o [k] to the lowest density. When the energizing time of the k-th gradation data up to the representative point a of the value is set and Y is an integer, 0 <
k <a, 0 <Y <a, and o [0] = 0 (always 0 applied energy for input 0) o [k] = o [a] × (Y / a + (1-Y / a ) × (k /
2. The thermal printer according to claim 1, wherein the energization time is determined by setting the integer based on the arithmetic expression of a)). 3.