JPS61123362A - Multi-gradation printer - Google Patents

Abstract

PURPOSE:To attain a change of multi-gradation at any time in accordance with correction of the characteristic of coloring density of a printer and the level of an input signal by providing a gradation characterized table on the basis of a parameter, etc. to be decided by the character of an analog input signal. CONSTITUTION:A colored and characterized table 12 representing the relation of the preliminarily measured and a decided electrically conducting time with coloring density, and software 13 to vary the contents of the table 12 by a parameter to be decided by characteristic of analog input signal are provided to a ROM11. A gradation characteristic table 10 changed uniformly the contents of the table 12 by a parameter to be decided by analog input signal S2 through software 13 is provided to a RAM9. Referring to the table 10 in accordance with an input signal, the most proper gradation representation can be used at each time to many different input signals. Thus, gradation change is made possible at any time in accordance with the correction of the characteristic of coloring density of a printer and the level of an input signal, the result can correspond to the user's requirement.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a multi-purpose computer that receives an analog signal such as a video signal and has means for correcting the coloring characteristics of a hard copy that expresses the image of the signal in multiple gradations. This relates to a gradation printer.

BACKGROUND OF THE INVENTION FIG. 2 shows the relationship between the energization time of a thermal head and color density in a thermal printer.

When obtaining a multi-gradation hard copy, if the energization time is determined directly based on the density level of the input signal, the density of the printed screen will be different from the density level of the input signal. Conventionally, in multi-gradation thermal printers, some kind of correction is generally made between the density level of the input signal and the energization time. An example of this is given below.

In FIG. 7, the pixel data 26 read out from the buffer memory in an appropriate order and the output of the reference V-pel signal generator 22 are compared by a magnitude comparator 23 to generate an energization signal for the thermal head. Reference level signal generator 2
The output No. 2 is obtained by sequentially producing wheat by the carry 26 of the preset counter 19, and the energization time is determined by the number of carries 26, which is an amount proportional to the pixel data 26. At this time, if the preset value of the preset counter 19 is changed every time a carry 25 occurs, the pixel data 26 will be
The energization time can be set to non-+7 = A. In this conventional example, in order to arbitrarily change the preset value, an address counter 21 receives a carry 26 as an input, and an RO counter 21 outputs internal data using its output as an address.
M20 is provided. By setting the internal data of the ROM 20 as the preset value of the preset counter 19, the ROM
By appropriately determining the internal data No. 20 in consideration of the relationship between the color density and the energization time, it is possible to arbitrarily determine the gradation of the printer.

Problems to be Solved by the Invention In the conventional example described above, changing the gradation requires rewriting the internal data of the ROM, for example, changing the gradation at any time depending on the input signal level. However, it is not possible to cope with changes in gradation according to the user's preferences.

In view of this, the present invention provides a multi-gradation printer that not only corrects the color density characteristics of the printer, but also changes the gradation at any time depending on the input signal level and the user's preference. O Means for Solving the Problem The multi-gradation printer of the present invention includes, as its constituent elements, a table representing the relationship between energization time and color density measured and determined in advance, and It has means for creating another table in which the contents of the table are uniquely changed based on parameters determined or parameters preset by the user, and according to an input signal,
This separate table is referred to and the energization time is determined based on its contents.

Function: The multi-tone printer of the present invention has the following characteristics according to the above parameters.
A unique function giving the energization time for an input signal level having the most appropriate gradation according to the signal is determined, and the separate table is created. By referring to this table according to the input signal, even for many different input signals,
Since the most appropriate gradation can be expressed and the gradation can be changed in response to changes in the input signal, work such as rewriting the ROM is completely unnecessary. Furthermore, by including parameters that can be preset by the user in the parameters of the function, it is possible to express gradation according to the user's preference.

Example An embodiment of the present invention will be described using FIGS. 1 to 6.

In FIG. 1, an analog input signal S2 from which a hard copy is to be obtained is first printed to a reference voltage by a clamper 2 in accordance with the input voltage of an A/D converter 7, and then printed to an appropriate voltage by an amplifier 3. amplified to the level. In response to the amplified analog input signal S4, the maximum level signal S6 of the analog input signal outputted by the peak voltage detection circuit 4 which receives this as an input, and the low-pass filter 5 which also receives the amplified analog input signal S4 as an input. A DC component level signal S6 of the analog input signal to be output is generated. Further, a variable resistor 18 that can be preset by the user is provided, and a preset voltage signal S1o is created by dividing the voltage. The respective signals are the amplified analog input signal S4, the maximum level signal of the analog input signal S6. DC component level signal S6 of analog input signal. The preset voltage signal S1o is connected to each input channel of an analog multiplexer 60 controlled by the CPUa, one of which is arbitrarily selected by the CPU5 and input to the A/D converter 7. A
The A/D converter 7 outputs the A/D converter 7 from the timing generator 1 which is synchronized with the synchronizing signal S1 of the input signal.
At clock S3, the analog input is converted into a binary value S.
7 and sends it to CPU 8. RAM 5, ROM 11, and buffer 14 are connected to CPU 8.
Inside the RoMll, there is a coloring characteristic table 12 that shows the relationship between the energization time and the coloring density, and this table is processed by a certain algorithm using parameters determined by the characteristics of the analog input signal S2 to create new gradations. Software 13 and the like for creating the characteristic table 1o are written therein, and the gradation characteristic table 10 is written in an appropriate area on the RAMQ, and is referenced by cptya at any time. Further, the thermal head energization time data S9 is latched by the CPU 5 in the buffer 14, and the pulse width modulator 16 outputs a thermal head energization signal having a pulse width proportional to the energization time data S9, and the thermal head energization signal is outputted through the head driver 16. The thermal head 17 is energized and a density corresponding to the energization time is recorded on the note copy.

Next, the characteristic operation of the present invention will be explained. Figure 2 shows an example of the relationship between energization time and color density, but as shown in Figure 3, the color density is divided equally into n stages on the graph to the extent that the required accuracy is obtained, and each Find the energization time data to obtain the concentration. At this time, as shown in Figure 3, each concentration is set in order from the lowest concentration to do, dl,...9,
The corresponding energization time data is set to t) t t('
)+...t(b). As shown in Figure 4, this data is
Write it on 0M11. This becomes the coloring characteristic table 12.

First, prior to the printing operation, the CPU 8 selects the maximum level signal S6 of the analog input signal using the analog multiplexer 6, and reads it as a binary coded value using the A/D converter 7. Let this value be KP.

Next, in the same way, the level signal S6 of the DC component of the analog input signal is read as a binary coded value, and this value is set as KL. Here, set the appropriate Seki Kai. This example shows the case where f(K)=a(b-K)'. Kp and KL determined by the characteristics of the input signal
is used to determine f(K) so as to satisfy the following relationship.

When K≦KPO, f) =n f(KL)=i fcKP)=0 ・・・・・・(1)K
) At KPO, from the relational expression f(6) −〇(1), f(K) = a (b K )
Each constant a of '.

After determining and organizing b and c, f(5)−〇 K>KP・・・・・・(
2) Create a new table using the function f(K> whose coefficients are specifically determined by the formula (2).Here, if the range of the binary coded values output from the A/D converter 7 is 0 If ≦ and ≦m, then a table with m+1 data will be created with l f(K
) I on RAMe. Here, If(6)1 represents the integer closest to f(K). Next, the CPUa sequentially reads out the m+1 contents of the table just created on the RAM 5, and uses the values as addresses to read out the contents of the coloring characteristic table 12 in the ROM 11.

For example, if the content read from RAM 5 is 0, t) is read out, and generally speaking, (for f(6)1, t
(If(K)l) is read from the ROM 11. As shown in Figure 5, 1f(6)1 is replaced with t(1f(6)l). This newly created table on RAMe is the gradation characteristic table 10.

After completing the above operations, the CPU 5 starts the printing operation. First, the analog multiplexer 6 selects a channel to select the amplified analog input signal S4, and the CPU 5 selects the analog input signal S from the A/D converter 7 at the timing provided by the timing generator 1.
The binarized numerical value S7 is sequentially read as a numerical value corresponding to 2.

The addresses of the gradation characteristic table 1o all have a one-to-one correspondence with the binary coded numerical values output from the A/D converter 7, and using the binary coded numerical values as addresses, the contents are extracted from the gradation characteristic table 1o in RAMe. Load. Since this content is energization time data, it is output as is to the buffer 14, and the pulse width modulator 15 energizes the thermal head 17 by a pulse width corresponding to the content of the buffer 14. -Explain the meaning of gradation of topography. In FIG. 6, the lower waveform shows an example of the amplified analog input signal S4. The horizontal axis of the graph is the binary coded value output from the A/D converter 7, and the vertical axis is the color density of the note copy.

The straight line f1 is a case where the maximum value and minimum value of the binarized numerical value are simply made to correspond to the minimum value and maximum value of the node copy to IJ near. Further, the curve 22 shows the change in color density of the hard copy obtained by the present invention.The 0 straight line y1 is a constant correction that is unrelated to the analog input signal S2. In the case of an input signal, the note-copied screen has no bright spots and is entirely dark, and even in the dark areas where the signal changes are most dramatic, the difference in color density is small and the contrast is poor.

However, in the correction according to the present invention, the peak of the analog input signal corresponds to the brightest density of the hard-copied screen, and the density change is greatest in the area where contrast is required. Moreover, the above features are compatible even when the analog input signal changes, and the average brightness of the screen is always approximately the same.

The operation of an example of the present invention has been described above, but the parameters determined from the characteristics of the analog input signal are not limited to this embodiment, and may be changed depending on the gradation of the note copy to be obtained. , other parameters may be selected, and the gradation characteristic table may be created.Also, as shown in FIG. If the above-mentioned parameter KL is obtained and KP is determined from an analog input signal, the gradation can be changed according to the user's preference.

In a multi-color, multi-gradation printer, similar corrections can be made by having each table as many as the number of the colors.

In addition to the effects of the invention, as described in the embodiments, the multi-gradation printer having the configuration of the present invention corresponds to the analog input signal to be printed, and the gradation of note copies is always the best. It is also possible to adapt to the user's preferences.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a multi-gradation printer according to an embodiment of the present invention, FIG. 2 is a graph showing changes in coloring density with respect to power supply time, and FIG. 3 is a graph showing the meaning of a coloring characteristic table.
Figure 4 is a schematic diagram showing the contents of the coloring characteristic table;
The figure is a schematic diagram showing the contents of the gradation characteristic table, and FIG. 6 is a schematic diagram showing the contents of the tone characteristic table.
FIG. 7 is a block diagram of a conventional printer. 4... Peak voltage detection circuit, 5... Low pass filter, 6... Analog multiplexer,
7...A/D converter, 8...
CPU, s...RAM. 10... Gradation characteristic table, 11...R
OM, 12... Color property table, 14...
...Buffer, 18...Variable resistor, S2...
... Analog input signal, S4 ... Amplified analog input signal, S6 ... Maximum level signal of analog input signal, S6 ... Level signal of DC component of analog input signal, S7...2 evolved numerical value,
S1o...Preset voltage signal. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Diagram 411 Danshu (mδ) Figure 3 U1'yt Audience Aj Daeg Figure 4 51!11 [α) (b) Figure 6 1 Audience Figure 7

Claims (4)

[Claims] (1) A thermal printer that performs intermediate density printing by varying the current application time to the thermal head is installed, and a table showing the relationship between the current application time and color density determined in advance and the characteristics of the analog input signal are used. means for creating another table in which the contents of the table are changed using at least one of the determined at least one parameter and at least one preset parameter before printing; A multi-gradation printer characterized in that the gradation property for an analog input signal at an intermediate density is changed by referring to the contents of a table according to the signal level of the analog input signal. (2) The multi-gradation printer according to claim 1, wherein at least one of the parameters determined by the characteristics of the analog input signal is the maximum level of the analog input signal. (3) The multi-gradation printer according to claim 1, wherein at least one of the parameters determined by the characteristics of the analog input signal is the level of the DC component of the analog input signal. (4) The multi-gradation printer according to claim 1, further comprising one or more variable resistors as means for presetting parameters before printing.