JP7253390B2 - PRINTING DEVICE, PRINTING METHOD AND PROGRAM - Google Patents

Description

The present invention relates to a printing device, printing method and program.

In recent years, as a card processing device that reads information from a magnetic card (hereinafter referred to as a card) or writes information to the card, a device that has a printing function for performing predetermined printing on the card to be processed has been considered ( For example, see Patent Document 1.).

JP 2018-52022 A

Not only in the card processing apparatus as described above, but also in a thermal transfer printer that performs predetermined printing on a card, there is a tendency that when the temperature of the print head exceeds a certain amount of heat, ink transfer is rapidly improved. Therefore, in order to exceed a certain amount of heat, density correction at the time of input is performed to increase the density of the entire image, thereby expressing printing that is close to the actual image. However, depending on the temperature of the print head and the external temperature, the expression of the print near a certain amount of heat becomes very unstable, and it cannot be compensated for only by density correction at the time of printing according to the temperature of the print head. There is a problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a printing apparatus, a printing method, and a program capable of maintaining print quality regardless of the apparatus environment temperature.

In order to solve the above problems, the printing apparatus of the present invention is arranged at a position at least a predetermined distance from a thermal head that heats an ink ribbon and transfers ink to a medium, and a thermometer that measures the temperature inside the apparatus. and,
and a control unit for correcting the density information of the original image to be printed based on the temperature measured by the thermometer.

In the printing apparatus of the present invention, the density information of the original image is corrected based on the temperature inside the apparatus measured at a position that is not affected by the temperature of the thermal head. Therefore, according to the present invention, the print quality can be maintained regardless of the ambient temperature of the apparatus.

In the printing apparatus according to the present invention, the control unit corrects the density information by changing a coefficient by which the gradation value, which is the density information of the original image, is multiplied based on the temperature. In this case, a coefficient corresponding to the temperature is used, and correction is performed by multiplying the gradation value by the coefficient, thereby making it easier to maintain the print quality corresponding to the temperature.

In the present invention, in the printing apparatus, the control unit corrects the density information of the original image so that the lower the temperature is, the darker the density information of the original image is, and the higher the temperature is, the lighter the density information of the original image is. Make corrections to those that indicate things. In this case, by separating the correction method for high temperature and the correction method for low temperature, it is easier to maintain print quality according to temperature.

In the present invention, in the printing apparatus, the control unit does not perform the correction on a portion where the value indicated by the grayscale information is the upper limit value, and the portion is corrected as the value indicated by the grayscale information approaches the lower limit value. greatly. In this case, it is easier to maintain the print quality by greatly correcting the pixels that are susceptible to the influence of the external temperature.

In the printing apparatus according to the present invention, the thermometer is arranged at a position where the temperature around the ink ribbon can be measured. In this case, it is possible to measure the temperature close to that of the ink ribbon in the device, without being affected by the temperature of the thermal head.

In order to solve the above problems, the printing method of the present invention is based on the temperature measured by a thermometer placed at a position at least a predetermined distance from a thermal head that heats an ink ribbon and transfers ink to a medium. , the process of correcting the density information of the original image to be printed is performed.

In the printing method of the present invention, the density information of the original image is corrected based on the temperature inside the apparatus measured at a position that is not affected by the temperature of the thermal head. Therefore, according to the present invention, the print quality can be maintained regardless of the ambient temperature of the apparatus.

In order to solve the above problems, the program of the present invention is provided in a computer,
A procedure for correcting the density information of the original image to be printed based on the temperature measured by a thermometer placed at a predetermined distance or more from the thermal head that heats the ink ribbon and transfers the ink to the medium. is characterized by executing

The program of the present invention corrects the density information of the original image based on the temperature inside the apparatus measured at a position not affected by the temperature of the thermal head. Therefore, according to the present invention, the print quality can be maintained regardless of the ambient temperature of the apparatus.

As described above, according to the present invention, the print quality can be maintained regardless of the ambient temperature of the apparatus.

1 is a diagram showing an embodiment of a printing apparatus of the invention; FIG. 2 is a diagram showing an example of the internal structure of the printing apparatus shown in FIG. 1; FIG. 4 is a flowchart for explaining an example of a printing method in the printing apparatus shown in FIG. 1; FIG. 4 is a diagram showing an example of correspondences between temperatures and coefficients stored in a memory;

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a printing apparatus according to the invention. A printing apparatus 100 according to the present embodiment has a thermometer 110 and a control section 120 as shown in FIG. It should be noted that FIG. 1 shows only main constituent elements of the present embodiment among the constituent elements of the printing apparatus of the present invention. FIG. 2 is a diagram showing an example of the internal structure of the printing apparatus 100 shown in FIG. As shown in FIG. 2, when a card is inserted from a card slot 190 provided in the printer 100, the transport motor 180 transports the card, and the thermal head 170 prints on the transported card.

A thermometer 110 is a temperature sensor that measures the temperature inside the printing apparatus 100 . The temperature measured by the thermometer 110 is defined as the device environment temperature. The thermometer 110 is arranged at a position separated by a predetermined distance or more from a thermal head 170 that heats the ink ribbon 140 and transfers the ink to a card, which is a medium. Also, the thermometer 110 is arranged at a position where the temperature around the ink ribbon 140 can be measured. Further, in the example shown in FIG. 2, the thermometer 110 is arranged near the supply roll 160 provided in the ink ribbon cartridge 130, but it is arranged near the take-up roll 150. can be Specifically, the position where the thermometer 110 is arranged is such that the temperature measured by the thermometer 110 is not affected by the temperature of the thermal head 170 and is close to the temperature of the ink ribbon 140 . This position is set based on the results of experiments, etc. conducted in advance. The thermometer 110 measures the temperature inside the printing apparatus 100 immediately before printing on each card. The timing at which the temperature sensor 110 measures the temperature inside the printing apparatus 100 may be every specific number of times of printing or every predetermined time period.

Based on the temperature measured by the thermometer 110, the control unit 120 corrects the density information of the original image to be printed on the card. Specifically, based on the temperature measured by the thermometer 110, the control unit 120 changes the coefficient by which the gradation value of each pixel of the original image is multiplied, thereby correcting the grayscale information. Here, the control unit 120 corrects each pixel of the original image. In addition, the control unit 120 performs correction such that the lower the temperature (0° C. or 5° C.) measured by the thermometer 110 is, the darker the original image is, that is, the correction is performed using a large value coefficient. On the other hand, the higher the temperature measured by the thermometer 110 (45° C. or 50° C.), the lighter the original image, that is, the correction is performed using a smaller value coefficient. Further, the control unit 120 does not perform correction on the portion where the value indicated by the grayscale information is the upper limit value, and performs greater correction on that portion as the value indicated by the grayscale information approaches the lower limit value. In other words, the control unit 120 performs correction such that the interval between the upper limit value and the lower limit value of the gradation value indicating the density of each pixel of the original image is narrowed without changing the upper limit value.

A printing method in the printing apparatus 100 shown in FIG. 1 will be described below. FIG. 3 is a flow chart for explaining an example of a printing method in the printing apparatus 100 shown in FIG.

Here, the temperature measured by the thermometer 110 is written in a memory (not shown) in the control unit 120 as needed. The method of writing this temperature to the memory may be overwriting (when writing a new temperature, the already written temperature is erased from the memory). Also, the memory stores the gradation value of each pixel of the original image. Further, the temperature and the coefficient are stored in advance in association with each other in the memory. In other words, the correspondence is stored in the memory in advance so that the temperature can be used as a search key to search the memory for the coefficient by which the gradation value of the target pixel is multiplied at what temperature. there is These pieces of information are input and stored based on operations received from outside the printing apparatus 100 and information transmitted from external devices.

FIG. 4 is a diagram showing an example of correspondence between temperatures and coefficients stored in memory. As shown in FIG. 4, the memory in the control unit 120 associates the temperature (t) with the coefficient (k) by which the gradation value is multiplied. By using this correspondence, it is possible to retrieve the coefficient (k) by which the gradation value of the pixel at that temperature is multiplied from the temperature (t). Note that the coefficient (k) may be expressed by an approximate expression for the temperature (t). This coefficient (k) has a larger value as the temperature (t) is lower.

First, the controller 120 reads the temperature measured by the thermometer 110 from the memory (step S1). Subsequently, the control unit 120 reads the gradation value of each pixel from the memory (step S2). Subsequently, using the read temperature as a search key, the control unit 120 reads the coefficient associated therewith from the memory (step S3). Then, the control unit 120 corrects the gradation value using the read coefficient (step S4).

（式１）における各パラメータを以下に示す。
Ｋ：入力時濃度補正係数（０～１）
Ｐ：注目画素の階調値
Ｑ：入力時濃度補正後の注目画素の階調値
（式１）では、階調値（Ｐ）が上限値（濃度が最も濃い値）である場合については、補正後の階調値が補正前のものから変化しないような値となっている。なお、（式１）を用いてそれぞれの温度に応じた補正後の画素の階調値をあらかじめ算出しておき、メモリ内に温度と補正後の階調値とを対応付けたテーブルを記憶させておき、制御部１２０が、階調値の補正時に、温度を検索キーとして、補正後の階調値をテーブルから読み出すものであっても良い。 An example of the tone value correction formula is shown in (Formula 1).

Each parameter in (Formula 1) is shown below.
K: Input density correction coefficient (0 to 1)
P: Gradation value of target pixel Q: Gradation value of target pixel after density correction at input In (Equation 1), when the gradation value (P) is the upper limit value (the value with the highest density), The gradation value after correction is a value that does not change from that before correction. Note that the gradation values of pixels after correction according to each temperature are calculated in advance using (Equation 1), and a table that associates the temperatures with the gradation values after correction is stored in the memory. Alternatively, the control unit 120 may read the corrected gradation value from the table using the temperature as a search key when correcting the gradation value.

After that, the control unit 120 determines whether or not correction has been completed for all pixels of the target original image (step S5). The control unit 120 repeats the processing of steps S2 to S4 until correction is completed for all pixels of the target original image. When all the pixels of the target original image have been corrected, the control unit 120 prints the image (step S6).

Thus, in this embodiment, the gradation value of the pixel is corrected based on the temperature inside the apparatus measured at a position not affected by the temperature of the thermal head and the gradation value of the target pixel. A coefficient for the gradation value is multiplied by the obtained coefficient for correction. Therefore, the print quality can be maintained regardless of the ambient temperature of the device.

In the above embodiment, the density information of the original image to be printed is corrected based on the ambient temperature of the apparatus measured by the thermometer 110. Density correction may also be performed. The correction according to the temperature of the print head may use the general method as described above.

It is also possible to correct the density of pixels by changing the timing for reading or changing the transport speed of the card.

As described above, each function (process) is assigned to each component, but this assignment is not limited to the above. Moreover, the configurations of the constituent elements are also only examples, and are not limited to these.

100 Printer 110 Thermometer 120 Control Unit 130 Ink Ribbon Cartridge 140 Ink Ribbon 150 Winding Roll 160 Supply Roll 170 Thermal Head 180 Conveying Motor 190 Card Slot

Claims (6)

a thermometer that measures the temperature inside the device and is placed at a position at least a predetermined distance from the thermal head that heats the ink ribbon and transfers the ink to the medium;
a control unit that corrects the density information of the original image to be printed based on the temperature measured by the thermometer ;
The control unit does not apply the correction to a portion where the value indicated by the grayscale information is the upper limit value, and applies the correction more greatly to the portion as the value indicated by the grayscale information approaches the lower limit value. The printing device according to claim 1, wherein
The control unit corrects the grayscale information by changing, based on the temperature, a coefficient to be multiplied by the gradation value of the original image as the grayscale information. In the printing apparatus according to claim 1 or claim 2,
The controller performs correction to indicate that the grayscale information of the original image is darker as the temperature is lower, and corrects such that the grayscale information of the original image is lighter as the temperature is higher. printer. In the printing apparatus according to any one of claims 1 to 3 ,
The printing apparatus, wherein the thermometer is arranged at a position where the temperature around the ink ribbon can be measured. A process that corrects the density information of the original image to be printed based on the temperature measured by a thermometer placed at a predetermined distance or more from the thermal head that heats the ink ribbon and transfers the ink to the medium. and
The correction processing is a printing method in which the correction is not applied to a portion where the value indicated by the grayscale information is the upper limit value, and the correction is applied to the portion as the value indicated by the grayscale information approaches the lower limit value. to the computer,
A procedure for correcting the density information of the original image to be printed based on the temperature measured by a thermometer placed at a predetermined distance or more from the thermal head that heats the ink ribbon and transfers the ink to the medium. wherein the correction is not applied to a portion where the value indicated by the grayscale information is the upper limit value, and the correction is applied more to the portion as the value indicated by the grayscale information approaches the lower limit value. program.

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