JPH04146162A - Recorder - Google Patents

Abstract

PURPOSE:To realize stabilized printing operation by outputting reference information from information to be recorded currently with reference to future information and providing a recording means with recording energy lower than a predetermined level based on the reference information even when the recording means does not record information on a recording medium. CONSTITUTION:Image data to be recorded is stored in a RAM 3 and transferred sequentially, as required, to a heat control circuit 5. The heat control circuit 5 determines the conduction pulse width of a line to be currently recorded with reference to past and future image data and thus determined pulse width data is transmitted to a thermal head driving circuit 6 for the image data of current line. The thermal head driving circuit 6 interprets thus determined pulse width data and drives a thermal head 7 to perform printing operation. According to the constitution, printing operation is carried out stably from start to end of recording operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a recording device that records information on a heat-sensitive medium.

(Prior Art) Currently, in the field of transportation, distribution, etc., media that allow prepayment and subtraction of charges, so-called prepayment cards, have come to be commonly used. The information recording method for this prepaid card is magnetic recording,
Thermal recording, mechanical drilling, etc. are used, but recently, methods of recording information using both magnetic recording and thermal recording have been increasing due to ease of use or convenience. Such a recording method must be sufficiently durable against various stimuli from the external environment (such as light, heat, magnetism or mechanical friction) in order to guarantee the reliability of the use of prepaid cards. There must be.

In thermal recording, security is improved when a metal film is used as the material for the recording layer, and currently tin (melting point 236°C) is used.
Cards that employ membranes are used as highly secure recording media. However, since thermal recording records by melting a metal film, the sensitivity of the recording film is much lower than that of thermal paper, etc., and it is difficult to obtain images with the same density as thermal paper. Requires high recording energy.

By the way, when thermal recording is performed continuously with a recording device, the temperature of the heating resistor of the thermal head differs between the start of recording and the end of recording due to heat storage. Print density may not be obtained. Also, after the space data,
For example, if you try to print one dot mark data,
Printing may not be possible because the temperature of the heating resistor has not reached the temperature required for recording. In order to prevent such problems and stabilize the image, heat storage control of the thermal head is generally performed.

A conventional heat storage control method is, for example, disclosed in Japanese Patent Application Laid-Open No. 6115469.
It is disclosed in the publication No. This method calculates the stored thermal energy of a line for recording an image by referring to one or more past lines, and then focuses on the calculated thermal stored energy and one or more lines in the future. This determines the current energization pulse width to the heating resistor.

(Problems to be Solved by the Present Invention) In conventional recording apparatuses, a heat storage control method as described above is introduced. In the heat storage control method, the past line is referred to rather than the current recording line in order to calculate the amount of heat storage. Also, referring to multiple lines in the future rather than the current recording line is because mark data is continuous in the past and data is recorded in the order of space data and mark data in the future. This is to prevent the area that should be whitened out from being crushed due to heat accumulation. As described above, the purpose of conventional heat storage control is that when high-speed recording is performed, the residual heat from past recordings is accumulated until the current recording, and the image density that was normal at the start of recording gradually changes. This is to prevent the image from becoming too dark or from deteriorating due to environmental changes.

However, although this heat storage control method is suitable for recording on conventional heat-sensitive recording paper, it is not suitable for printing on prepayment cards that use thin metal films to improve security, which are being used recently. do not have. In other words, the conventional heat storage control method sets the coloring threshold at a relatively low temperature to the recording material (
For example, when using heat-sensitive recording paper, ink ribbon for thermal transfer recording, etc. at a temperature of approximately 60 to 80 degrees Celsius, color may develop in non-print areas around the print area. The purpose is to control the energy of For example, if the area of interest for recording is continuous space data, no current is applied, and when subsequently outputting mark data, the current is not applied when the mark data is continuous and the mark data is output again. This is a control method that lengthens the time. However, with this control method, when printing on a recording medium with low sensitivity such as a thin metal film recording material, the energization time is extremely long and a large amount of recording energy is supplied to the heating resistor. There must be. For this reason, when transitioning from continuous space data to mark data, the recording energy supplied to the heating resistor for printing may exceed its permissible value, or the thermal stress generated on the heating resistor due to the temperature difference may be extremely severe. This poses a problem in that as the thermal head becomes larger, the head wears out more and the life of the thermal head becomes shorter.

Therefore, an object of the present invention is to provide a recording device that can perform printing stably from the start of recording to the end of recording.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for recording information on a recording medium in which information is recorded by applying and accumulating a predetermined value of recording energy. A recording means for recording, a reference area setting means for setting a reference area for referencing multiple pieces of future information from the information recorded by the recording means, and outputting information within the reference area set by the reference area setting means. an information outputting means for recording information, and recording energy such that when no information is recorded on the recording means or the recording medium, the recording energy stored in the recording means is equal to or less than a predetermined value based on the information outputted by the information outputting means. It is characterized by comprising a means for applying to the means.

(Operation) The recording device of the present invention outputs reference information by referring to information in the future than the information to be recorded at present, and even when the recording means does not record information on the recording medium, it records based on the reference information. The recording device is provided with recording energy such that the recording energy stored in the device is equal to or less than a predetermined value.

(Embodiment) Hereinafter, one embodiment of the recording apparatus of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of a recording apparatus using a line thermal head. This recording apparatus is composed of a main control section, a recording section, a conveying section, a sensor section, and the like.

The main control unit is composed of a CPUI, ROM 2, RAM 3, and character generator 4.
The UI controls all of these ROM 2, RAM 3, character generator 4, recording section, transport section, sensor section, etc.

The recording section includes a thermal control circuit 5, a thermal head drive circuit 6, and a thermal head 7. calculating the heat storage energy of the heating resistor corresponding to the pixel of interest to be printed by referring to past pixel data; predicting the heat storage energy of the heating resistor corresponding to the pixel of interest by referring to future pixel data; When the pixel of interest is space data, the thermal control circuit 5 determines the energy input to the heating resistor with less energy than the energy required for recording in accordance with the predicted heat storage energy. .

The conveyance section includes a conveyance motor control circuit 8, a conveyance motor drive circuit 9, and a conveyance motor 10.

Next, the procedure for recording an image will be described below.

Image data (pixel data) to be recorded is stored in the RAM 3, and is sequentially transferred to the thermal control circuit 5 as required. As described above, this thermal control circuit 5 refers to past and future image data, determines the energizing pulse width of the line to be currently recorded, and thermally converts the pulse width data and the image data of the current line. It is transmitted to the head drive circuit 6. The thermal head drive circuit 6 interprets the pulse width data determined by the thermal control circuit 5 and drives the thermal head 7, so that the thermal head 7 performs recording.

Here, a method for determining the energization pulse width for a pixel of interest based on a pattern of image data will be described. In FIG. 2, (a) is the image data to be recorded, the j column is in the time axis direction, and (b) and (C) are the energizing pulses determined and supplied in the recording apparatus of the present invention, respectively. (d) represents the change in temperature of the heating resistor over time.
and (e) show examples of changes over time in the current pulses supplied in the conventional recording apparatus and the temperature of the heating resistor, respectively. In the figure, tl to t5 are the energization pulse times, Ta is the environmental temperature, Tt is the temperature threshold necessary for recording, and to is the recording time during which image data is recorded exceeding the threshold Tt. , ΔT1 represents the amount of temperature rise necessary when recording mark data in the recording apparatus of the present invention, and ΔT2 represents an example of the amount of temperature rise necessary when recording mark data in the conventional recording apparatus. The reference area that refers to past and future image data is
In Figure 2, 1 to 5, the 3×
4, and is configured as one current line, one past line, and two future lines with the pixel of interest P as a reference.

In the state of Figure 2 (1), referring to the coordinates in Figure 2 (a), the pixel of interest P(n, i) is space data, and the mark data is the pixel of interest P three lines ahead. Only in the same column position (n + 3.i).

In the state of 1>, the recording device of the present invention takes into consideration that the current line in the matrix is space data and that mark data exists three lines ahead of the pixel P of interest, and the heating resistor temperature or coloring threshold Tt
A short energization pulse for preheating the heating resistor is generated for a energization pulse time t1 as follows.

Next, the state shown in Fig. 2 (2), that is, the pixel of interest P
At the time of (n+1.i), the pixel of interest P is space data, but there is mark data two lines in the future in the same column as the pixel of interest P. In this case, mark data exists in the future line in the matrix, and a short energization pulse for preheating is applied to the previous line in the past.
1) The heating resistor reaches the coloring threshold T, taking into account the fact that the heating resistor is energized and the heat storage energy calculated by referring to the amount of heat released during the change from the state 1) to the state 2).
An energization pulse for a energization pulse time t2 that is equal to or slightly shorter than the energization pulse time t1 is generated so that the temperature becomes equal to or less than t.

Next, the state shown in Fig. 2 (3), that is, the pixel of interest P
When (n+2.i), the next line in the same column as the pixel of interest P is mark data, and the next line is space data. At this time, as in the case of 2> in FIG. 2, an energizing pulse time t3 equal to or slightly shorter than the energizing pulse time t2 is generated so that the temperature of the heat generating resistor becomes equal to or lower than the coloring threshold Tt.

As shown in FIGS. 2(d) and 2(e), in the conventional recording apparatus, since the target pixel P is space data, no heat is supplied to the heating resistor, that is, no energizing pulse is generated.

Next, the state of 4> in FIG. 2, that is, the pixel of interest P
When (n+3.i), the pixel P of interest is mark data. At this time, the heating resistor generates an energizing pulse for a energizing pulse time t4 necessary for recording. and,
The temperature of the heating resistor increases by ΔT1, and information is printed when the temperature exceeds the temperature threshold Tt necessary for recording. The recording here is performed for a recording time t in the area exceeding the coloring threshold Tt.
.

only. In conventional recording devices, in order to obtain the recording time to required for recording, the temperature of the heating resistor is changed from Ta to Δ
In order to raise the voltage to T2, it is necessary to perform an energization pulse with an energization pulse time t5, which is longer than the energization pulse time t4.

In other words, in the conventional apparatus, in order to obtain the recording time to, the temperature of the heating resistor must be increased from Ta to ΔT2, whereas in the recording apparatus of the present invention, the pixel P of interest is space data. Also, since the heating resistor corresponding to the pixel of interest P was preheated for future mark data, the temperature rise of the heating resistor when the pixel of interest P is mark data is ΔT1 (ΔT2). That's fine.

Therefore, according to the recording device of the present invention, the energizing energy per pixel may be small, the maximum heating temperature of the heating resistor can be kept low due to the effect of the heat storage energy, and the temperature change rate per unit time can be kept low. Since there is less thermal stress etc., stable recording can be performed.

The relationship between the reference data pattern and the energization pulse time when the pixel of interest is space data, as described above, is summarized as follows.

(1) If image data of a future line in the matrix exists, determine the energization pulse time such that the heating resistor corresponding to the pixel of interest does not exceed the coloring threshold.

(2) Refer to the image data of the future line, and if no mark data exists, do not energize.

Further, the reason why two future lines are referred to in the present invention is as follows. 3G As shown in (a), when there is image data with a repeating pattern of mark data and space data with a period of one dot, the reference area (the area surrounded by a large frame in Figures 3(b) and (c)) can only refer to one line of image data in the future, as shown in Figure 3 (
The situation as shown in b) occurs, and it is not possible to detect that the pattern is a repeating pattern with a one-dot period, as shown in Figure 3 (C).
This is because such space data cannot be distinguished from a continuous state, making it impossible to reduce thermal stress by keeping the rate of temperature change per unit time small, for example.

In the above description, the case where the mark data for the pixel of interest is in the same column as the pixel of interest has been explained. However, it goes without saying that if the mark data is not in the same row but is in the matrix, preliminary heating control can be performed by the same operation as described above. Alternatively, the heat storage energy may be calculated by weighting the mark data in the reference area for the pixel of interest according to its position.

Next, as shown in FIG. 4(a), the heat storage energy of the heating resistor corresponding to the pixel of interest to be printed is calculated with reference to past pixel data, and the pixel of interest is calculated with reference to future pixel data. Prediction of the heat storage energy of the heating resistor corresponding to the target pixel or space data, and inputting energy to the heating resistor with less energy than the energy required for recording in accordance with the predicted heat storage energy. A block diagram of a thermal control circuit 5 that determines energy is shown. The thermal control circuit 5 includes a shift register 12, a pulse width calculation section 13, a line buffer 14, a data extraction and data updating section 15, and the like. Here, in Figure 4 (
Set a reference area like b) and select the pixel of interest P(n,i)
The procedure for determining the pulse width for recording will be described below. Note that in order to record n lines, a buffer with a capacity for 3 lines is provided as a reference method for future image data of lines n+1 to n+3.
The image data of lines n+1 and n+2 are transferred first, and when the image data of line n+3 is transferred, line n is recorded. 1, 2, . . . i-1, i, i+1. on line n+3 from RAM. ...
The th image data is serially transferred to the shift register 12. At this time, the shift register 12 performs serial-parallel conversion on the n+3 lines of image data and extracts image data around the pixel P of interest. These image data are input to the pulse width calculation section 13. At this time, the line buffer 14 stores image data of lines n to n+2 that were transferred before the currently transferred line. The data cutting and data updating unit 15 extracts image data corresponding to the reference area from the image data stored in the line buffer 14 and transfers it to the pulse width calculation unit 13, and at the same time, the data is stored in the line buffer 14. The image data of line n is transferred to n+.
The image data is sequentially updated to 3 lines.

In the pulse width calculation section 13, the data extraction and updating section 1
i-1 of lines n, n+1 and n+2 transferred from 5
, i, i+1-th image data and the i-1, i, i+1-th image data of n+3 lines transferred from the shift register 12, calculate the energizing pulse width (time) of the pixel of interest P, and output the pulse width data. do. Pulse width calculation section 13
is composed of a ROM and the like that stores a lookup table in which image data patterns and pulse width data are associated with each other.

FIG. 5 shows the relationship between the pulse width data determined by the pulse width calculating section 13 and the energizing pulse to the thermal head. In this embodiment, the pulse width data is expressed by 4 bits, and each bit is E as shown in FIG. 5(a).
It corresponds to NL1, ENL2, ENL3, and ENL4, and can generate 16 types of energization pulse trains by combining them. For example, if pulse width data of 1101" is input, ENL1, ENL2, and ENL4 are selected, ENL3 is not selected, and the
) The energizing pulse train will be as shown in (). As described above, the energization time is controlled by the combination of basic pulses.

As explained above, the apparatus of the present invention is capable of clearly performing one-dot line printing that requires a large amount of recording energy even on media with high security and a high threshold of recording sensitivity. Printing with stable print quality can be performed until the end of recording. Furthermore, the energy supplied to the heating resistor of the thermal head can be reduced and the thermal stress generated in the heating resistor can be alleviated, so that the life of the heating resistor can be extended.

[Effects of the Invention] As detailed above, according to the present invention, stable printing can be performed from the start of recording to the end of recording.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the recording device of the present invention, and FIG. 1 is a schematic diagram of the configuration of the recording device of the present invention, and FIG. A diagram for explaining the relationship between the energization pulse and the temperature of the heating resistor,
FIG. 3 is a diagram for explaining the range of the reference area, FIG. 4 is a block diagram of the thermal control circuit, and FIG. 5 is a diagram showing the relationship between pulse width data and energizing pulses. 5... Thermal control circuit 6... Thermal head drive circuit 7... Thermal head

Claims (1)

[Scope of Claims] A recording means for recording information on a recording medium on which information is recorded by applying and accumulating a predetermined value of recording energy; a reference area setting means for setting a reference area for referencing information on the reference area; an information outputting means for outputting information in the reference area set by the reference area setting means; and an information outputting means for outputting information in the reference area set by the reference area setting means, and applying means for applying recording energy to the recording means such that the recording energy stored in the recording means becomes equal to or less than the predetermined value based on the information outputted by the information outputting means when information is not recorded by the information outputting means. A recording device characterized by: