JP3235072B2 - Control method of thermal recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a thermal recording apparatus which performs recording control in accordance with the conditions of a recording medium such as thermal recording paper.

[0002]

2. Description of the Related Art FIG. 6 is a diagram showing the structure of a thermal recording apparatus of this type. The thermal recording apparatus is composed of a plurality of heating resistors and is based on heat generated by power supply from a power source E to the heating resistors. 1, a thermal circuit 2 for controlling the thermal head 2, a control circuit 3 for controlling the thermal head 2,
And a circuit 4 for adjusting the energy supplied to the thermal head for adjusting the recording density. Incidentally, the recording medium such as the thermal recording paper 1 or the ink ribbon used in the thermal recording apparatus has its own coloring characteristics. FIG. 7A is a diagram showing the coloring characteristics of a certain recording medium. The horizontal axis indicates the power supply E for the thermal head 2.
, The vertical axis on the left is the degree of color development (reflection density; OD... Opt) with respect to the supplied energy.
ical density) and the right vertical axis indicate the change in the resistance value of the heating resistor of the thermal head 2 with respect to the supplied energy.

Here, the reflection density of the recording medium is shown in FIG.
As shown by the curve indicated by the symbol (a), the density initially increases in proportion to the energy supplied to the thermal head 2, and after a certain value, the amount of increase in the reflection density decreases with an increase in the supplied energy. . When the supply energy of the thermal head 2 is further increased, the resistance value of the heating resistor of the thermal head 2 increases as shown by a curve indicated by a sign, and the heating resistor is destroyed. In the conventional thermosensitive recording apparatus, recording is performed by appropriately setting a value that is equal to or lower than the destructive energy and obtains an appropriate recording density as the energy supplied to the thermal head 2 based on such a coloring property. ing.

Further, the energy supplied for obtaining the proper printing varies depending on environmental conditions such as the ambient temperature as shown in FIG. Therefore, in the conventional apparatus, the supply energy is determined based on the environmental condition characteristics of the standard medium, and the supply energy adjustment circuit 4 shown in FIG. Set each condition. As a result, the control circuit 3 drives the thermal head 2 in accordance with the conditions set in the supply energy adjusting circuit 4 so that an appropriate density is recorded.

[0005]

As described above, in the conventional thermal recording apparatus, every time the recording medium to be used is changed, the supply energy to the thermal head is appropriately adjusted by the supply energy adjusting circuit based on the color development characteristics. In addition, even when a plurality of types of media are used, appropriate recording can be performed in accordance with these media. Therefore, when changing the recording medium to be used, appropriate adjustments cannot be made unless the coloring characteristics and environmental characteristics are grasped in advance. There has been a demand for the development of a device capable of recording on a computer.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to automatically perform recording with an appropriate thermal head supply energy according to each recording medium in a thermal recording apparatus.

[0007]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention comprises a plurality of heating resistors for generating a heat amount corresponding to the supplied energy amount, and energy is selectively supplied. In a thermal recording apparatus having a thermal head for performing recording on a recording medium in accordance with heat generated by each heating resistor, a detecting unit for detecting a change amount of a recording density or a shape change in the recording medium recorded by the thermal head, and control means for controlling the energy supplied to the thermal head on the basis of the detection output of the detecting means, and an energy varying means for varying the supply amount of energy with respect to support Maruheddo provided, the control means energy varying means Control to increase the amount of energy given to the thermal head in steps of unit energy At the same time, the amount of change in the recording density or shape change in the recording medium detected by the detecting means is calculated for each step, and the difference between the calculated amount of change and the amount of change calculated one step before is calculated. This is to detect an appropriate amount of energy supply to be supplied. Further, the control means calculates the difference between the calculated change amount and the change amount calculated one step before, and detects the appropriate energy supply amount by comparing the calculated value with a predetermined value. It was done.

[0008]

The amount of change in the recording medium recorded by the thermal head, that is, the recording density on the thermal paper in the thermal recording apparatus, the density of the ink transferred from the ink ribbon to the recording paper in the thermal transfer recording apparatus, and the recording density in the Braille printer Detect the size of the expanded shape formed on the paper,
It is assumed that the amount of energy supplied to the thermal head is automatically controlled according to the detected amount of change in the recording medium.
In addition, the energy variable means is given to the thermal head.
Energy increases by one unit of energy per unit
The amount of change in the recording medium detected at this time.
In addition to the calculation for each stage,
Detects the appropriate amount of energy supply from the difference from the calculated change
I do . As a result, the shape formed on the recording density or the surface of the recording medium will be automatically adjusted, thus it is possible to perform automatically the proper recording on a recording medium, accurately the proper energy supply Can be detected. If the difference between the calculated change amount and the change amount calculated one step before is larger than a predetermined value, it is determined that the energy is appropriate. As a result, the appropriate energy supply amount can be accurately detected with a simple configuration.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a thermal recording apparatus according to the present invention.
6, a thermal recording paper 1, a thermal head 2, and a control circuit 3 are the same as in the conventional example of FIG. In addition, the thermal recording apparatus is provided with a density detection sensor 11 for detecting the recording density of the thermal recording paper 1, and the detection output of the density detection sensor 11 is sent to the control circuit 3 via the density detection circuit 12. Is transmitted. Further, a head control circuit 13 for driving and controlling the thermal head 2 is provided. The head control circuit 13 drives the thermal head 2 in accordance with the recording data output from the control circuit 3 and, at this time, varies the energy. An amount of energy is supplied from the power supply E to the thermal head 2 via the circuit 14.

The thermal recording apparatus has a platen 15 for transporting the recording paper 1 and a platen 15 in addition to the above components.
, A motor driving circuit 17, and a storage device 18 are provided. By the way, the storage device 18 stores the unit energy increase amount Δε (specified value), the recording density D of the predetermined pattern detected by the density detection sensor 11, and the energy amount εB (specified value) supplied from the head control circuit 13 to the thermal head. Each of them has an area for storing and holding, and the control circuit 3 detects the energy supplied to the thermal head 2 so that the density becomes appropriate based on the stored values.

In addition, the control circuit 3 supplies the above-mentioned head control circuit 13 for selectively driving and controlling the heating resistor of the thermal head 2 based on the recording data, and supplies the thermal head 2 from the power source E. Each of the above-described energy variable circuits 14 that variably controls the applied power is controlled.

FIG. 3 is a diagram showing a recording state of the thermal head 2 of the apparatus of the embodiment on the thermal recording paper 1.
FIG. 3A shows the case where the energy supplied to the thermal head 2 is small, FIG. 3B shows the case where the supplied energy is medium, and FIG. 3C shows the case where the supplied energy is large. FIG. 3 shows that the recording density is low when the supplied energy is small, and the recording density is increased as the supplied energy increases.

The relationship between the supply energy (ε) of printing to the thermal head 2 and the recording density (D) is as shown in the graph of FIG. In other words, it can be seen that the recording density becomes higher as the supplied energy increases, but after the saturation point B is reached, the recording density does not become higher even if the supplied energy is further increased. As described above, when the supply energy of printing to the thermal head 2 increases, the recording density recorded on the thermal recording paper 1 increases, so the apparatus of the present embodiment detects this recording density and detects the detected recording density. The energy supplied to the thermal head 2 is controlled so that the density becomes appropriate.

FIG. 2 is a flowchart showing the operation of the control circuit 3 for detecting an appropriate density. The operation of the main part of this embodiment will be described with reference to this flowchart. First, when the power is turned on by the operator, the control circuit 3 resets the storage device 18 in step S1, and sets the above-mentioned respective values stored and held in the storage device to initial values. By this initial operation, the recording density D is “0”, the change amount dD / dε of the recording density is “0”, the energy amount ε supplied to the thermal head 2 is a unit energy amount Δε (where Δε is the destruction of the thermal head 2). (A value sufficiently smaller than the energy amount εB).

Next, the control circuit 3 drives the motor 16 and the platen 15 at a predetermined speed by the motor drive circuit 17 to feed the recording paper 1 and at step S2
Controls the energy variable circuit 14 with the thermal head 2
Then, an energy amount ε is supplied for printing, and recording is performed on the thermal recording paper 1, for example, as shown in FIG. Thereafter, the process proceeds to step S3, where it is stored in the storage device 18 whether or not the energy amount ε supplied to the thermal head 2 has reached the destruction energy amount εB for destroying the heating resistor of the thermal head 2. The detection judgment is made by comparing the values ε and εB. Here, when it is determined that the destructive energy amount εB is supplied to the thermal head 2, the process proceeds to step S10, and an error process for notifying the operator of the occurrence of an error is executed.

On the other hand, when it is determined that the energy equal to or less than the breaking energy is supplied to the thermal head 2, the process proceeds to step S4, and the recording density DN of the recording portion recorded by executing step S2 is detected. Detection is performed via the sensor 11 and the density detection circuit 12. Next, the control circuit 3 proceeds to step S5, where the recording density DN detected via the density detection sensor 11 and the like, the recording density D stored in the storage device 18, and the energy previously supplied to the thermal head 2 From the amount ε, a change amount dD / dε of the recording density is calculated based on the following equation. That is, dD / dε = | DN−D | / Δε

Subsequently, in step S6, the energy amount ε supplied to the thermal head is equal to the unit energy increase amount Δ
It is detected whether or not it is ε. If both are equal, the change amount dD / dε of the recording density calculated in the previous step is stored in the storage device 18 and the process proceeds to step S8. In addition,
If ε = Δε in step S6, it is limited to immediately after the power is turned on to the apparatus.

In step S8, the amount of energy .epsilon.
“ε + Δε” for adding ε is executed, the calculated energy amount ε is stored in the storage device 18, and the process returns to step S2.
In this manner, the unit energy increase amount Δε is added to the supplied energy amount ε of the thermal head 2. Therefore, if the processing from the next step S2 to step S5 is performed, in step S6, unlike the case immediately after the power is turned on, the thermal head 2 is larger than the unit energy increase amount Δε, so that the process proceeds to step S7.

In step S7, the magnitude of each value of the recording density change amount dD / dε calculated in step S5 immediately before this process and the value of the recording density change amount dD / dε stored in the storage device 18 in the previous process. Is compared. At this time, if the difference between the recording density change amount calculated in step S5 and the recording density change amount stored and held in the storage device 18 in the previous processing does not exceed the predetermined value, step S4
It is determined that the recording density DN detected in step S2 has not reached the appropriate density, that is, the energy amount ε supplied in step S2 has not reached the appropriate energy. And in this case,
The calculated recording density change amount dD / dε is stored in the storage device 18 and the process proceeds to step S8, where the above described “ε + Δ
演算 ”is calculated, the value is stored in the storage device 18, and the process returns to step S2.

When the processes in steps S2 to S8 are sequentially repeated, the energy amount ε supplied in step S2 reaches an appropriate energy amount, and therefore, the recording density change amount dD / dε at this time is extremely small. That is, the difference between the calculated recording density change amount determined in step S7 and the recording density of the storage device 18 exceeds a predetermined value. That is, at this time, the control circuit 3 determines that the amount of energy supplied to the thermal head 2 is an appropriate amount of energy and shifts to step S9. That is, this point is a point in time when the saturation point B shown in FIG. 4 is reached, and the energy at this point is optimized and the process proceeds to step S9. Then, the energy supply amount ε at this stage is stored in the storage device 18 as the optimum energy, and thereafter, the optimum energy amount is supplied to the thermal head for printing. As a result, recording is performed on the thermosensitive recording paper 1 at an optimum density.

As described above, when recording is performed on the thermal recording paper 1 by the thermal head 2, the energy applied to the thermal head 2 is increased stepwise by a unit energy amount Δε, and the recording density detected during this time is used as the energy. The change amount is calculated and the difference between the change amounts is calculated, and the supplied energy when the difference exceeds a predetermined value is set as the energy that can be recorded at the optimum density.

As the medium in the thermal recording apparatus, there are thermal transfer and thermal expansion materials and the like in addition to the thermal recording paper described above. Here, the above-mentioned thermal expansion material is a material formed on the surface of the recording paper by a material that expands by applying heat, and is used as a recording material of a Braille printer. In such recording paper, when the energy supplied to the thermal head is small, the amount of expansion of the expandable material, that is, the amount of change in shape of the surface of the recording paper is small, and as the supplied energy increases, the change in shape of the surface of the recording paper increases. . In such a recording paper, a reflection type sensor is used as a detection sensor, light from a light source is reflected on the surface of the recording paper, and a change in shape of the recorded recording paper surface is detected by detecting the amount of light.

That is, in such a recording paper, the light from the light source is reflected and scattered as the shape change formed on the surface thereof increases, and as shown in FIG. 5, the energy ε supplied to the thermal head increases. Accordingly, the light amount L detected by the detection sensor decreases. Therefore, when detecting a change in the shape of the recording paper surface of the recording paper, the appropriate supply energy is detected based on the change in the amount of light (dL / dε) shown in FIG. When the above-described thermosensitive recording paper 1 is made of a transparent material, the density detection sensor is not a reflection type but a transmission type sensor.

[0024]

As described above, according to the present invention, the recording density of a recording medium recorded by a thermal head is detected, and the amount of energy supplied to the thermal head is automatically determined according to the detected recording density. Tomo and control to
To the thermal head for the energy variable means
The amount of energy is increased in steps of one unit energy
And the amount of change in the recording density detected at this time
And the calculated change amount and one step before
The recording density of the recording medium is automatically adjusted because the proper recording density is detected from the difference from the change amount, so that the recording with the proper density is automatically performed on the recording medium. In addition, the appropriate recording density can be accurately detected. Further, when the difference between the calculated change amount and the change amount calculated one step before is larger than a predetermined value, the appropriate recording density is determined, so that the appropriate recording density can be accurately detected with a simple configuration. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a thermal recording apparatus of the present invention.

FIG. 2 is a flowchart showing an operation of the apparatus in the embodiment.

FIG. 3 is a diagram illustrating a recording state on a recording sheet of the apparatus according to the embodiment.

FIG. 4 is a graph showing a relationship between supply energy and a recording density in the apparatus of the embodiment.

FIG. 5 is a diagram illustrating another example of the case where the recording density is detected in the apparatus according to the embodiment.

FIG. 6 is a diagram showing a configuration of a conventional device.

FIGS. 7A and 7B are diagrams illustrating a recording density and a change in resistance value of a thermal head with respect to supplied energy, and a diagram illustrating a relationship between ambient temperature and supplied energy.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Thermal recording paper, 2 ... Thermal head, 3 ... Control circuit, 11 ... Recording density detection sensor, 12 ... Density detection circuit, 13 ... Head control circuit, 14 ... Energy variable circuit, 18 ... Storage device, E ... Power supply.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/36

Claims (2)

(57) [Claims] 1. A recording medium, comprising a plurality of heating resistors for generating a heat amount corresponding to the supplied energy amount, recording on a recording medium according to the heat generation of each heating resistor to which energy is selectively supplied. A thermal recording apparatus having a thermal head for performing a recording operation, a detecting unit for detecting a recording density or a shape change in a recording medium recorded by the thermal head, and an energy supplied to the thermal head based on a detection output of the detecting unit. and control means for controlling the
Variable amount of energy supplied to the thermal head
And a variable energy means for said control means, said support relative to said energy varying means
-The amount of energy given to the multiple head is the unit energy
Control and increase the value of each step.
Recording density on the recording medium detected by the means
Or the amount of change in shape change is calculated for each stage, and the calculated change
Thermal difference from the difference between the amount of
Detects the appropriate amount of energy supplied to the head
Control method of the thermal recording apparatus characterized by that. 2. A method according to claim 1, wherein said control means calculates a difference between the calculated output and the amount of change and the change amount calculated in one step before, the calculated value magnitude and predetermined
A control method for a thermal recording apparatus, wherein an appropriate energy supply amount is detected by comparing the value with a value .