Abstract: A recording head using thermal energy includes a plurality of heat generating elements for producing thermal energy; a waveform storing circuit for storing waveform data for a driving signal or signals applied to one or more predetermined number of heat generating elements; and a driving signal applying device for applying to each of the predetermined number of heat generating elements the driving signal or signals on the basis of the waveform data stored in said storing circuit, in accordance with a record image signal or signals.

Abstract: When a position deviation of more than 1/2 pitch of ejection port pitch is generated by a difference in thermal expansion between ejection ports of a low temperature line head and ejection ports of high temperature line head, a dummy data is inserted in part of ejection data arrangement, so that ejection data inherent in the arrangement is shifted by one ejection port unit to be assigned to other ejection ports This reduces position deviation between dots formed by individual heads according to the data to less than 1/2 pitch.

Abstract: A thermal transfer printing device for printing photorealistic color images with dye-sublimation inks of different colors and two-gradation images such as character and bar code patterns with a monochrome thermal wax-transfer ink respectively in separated printing sections. The bar code pattern is printed in the widthwise direction of the code bars with heating energy smaller than that for printing the bar code pattern in the lengthwise direction of the bars, thus increasing the reproductivity in producing the bar code pattern. Deviations in specific resistance among heating elements of a thermal print head can be compensated by multiplying image data energy to be supplied to the heating elements by ratios of the specific resistance of the respective heating elements to the maximum resistance in the heating elements, thus producing high-quality images on the recording medium.

Abstract: A method and apparatus for maximizing print quality in a thermal printer uses a ribbon condition monitor to detect the condition of a multipass thermal ribbon. Data related to the condition of the thermal ribbon at each individual pixel is used to determine a custom energization signal for each thermal print element. In one embodiment, the system utilizes a history memory to track the prior heating history of each thermal print element and an ink memory to track the prior use of each location on the thermal print ribbon corresponding to the thermal print elements. The data from the history memory and the ink memory are combined to form an index to a table memory containing data corresponding to a plurality of energization signal levels for a particular print medium. The data in the table memory provides the custom energization signal for each of the thermal print elements. In an alternative embodiment, a light source and detector are used to determine the thickness of ink remaining on the thermal ribbon.

Abstract: A standard resistor having a known resistance value is connected to one transistor in a drive IC. The drive IC has a plurality of transistors each controlling the on/off of a heating element. The saturation voltage of each transistor is generally the same. One of a plurality of transistors is turned on, and a discharge time required for a capacitor to discharge via a standard resistor or via each heating element and lower its voltage to a predetermined voltage is measured. The resistance value of each heating element is determined from a ratio of a discharge time via each heating element to a discharge time via the standard resistor and the resistance value of the standard resistor. A difference between the standard resistance value and a resistance value of each heating element generates a bias heat energy error during bias heating and an image heat energy error during image heating. In accordance with these heat energy errors, bias data for generating a heat energy immediately before coloring is corrected.

Abstract: A temperature controlling method and apparatus for a thermal printhead, in which a temperature of a thermosensitive recording material is detected by measuring a temperature change of the thermal printhead when a surface of the thermosensitive recording material contacts a surface of the resistant heater of the thermal printhead. The thermosensitive recording material is heated by the thermal printhead to a temperature suitable for recording or erasing an image on the thermosensitive recording material, with the temperature suitable for recording or erasing the image being changed as a function of the detected temperature of the thermosensitive recording material.

Abstract: A method of and apparatus for compensating printing heads which operate in thermal drop on demand printing modes for the effects of thermal lag includes a counter which provides a number representing the amount of elapsed time during a heater energizing pulse as a proportion of the entire pulse duration. The output of the counter is connected to a device which determines the power supply voltage required at the said elapsed time. This result is used to control a programmable power supply which is connected to the heater power supply of the print head. The device is preferably a lookup table stored in digital memory, containing a pulse waveform calculated using iterated transient finite element analysis of the thermal state of the nozzle during simulated operation.

Abstract: A method calibrating a thermal print head printer having fixed imaging elements so that consistent high resolution output may be achieved includes a means for measuring a common characteristic of each fixed imaging element and storing the values so that print head compensation may occur during the printing process one scan line at a time. Error diffusion, either across the thermal print head, down-web, or both, ensures that appropriate drive level are supplied to each fixed imaging element regardless of inherent differences in the common characteristics of the fixed imaging elements, to achieve consistent tonal image quality. In a preferred embodiment, the fixed imaging elements are thin film electrical resistive elements and the common characteristic is the electrical resistance of the thin film resistor elements.

Abstract: A method for printing by thermal sublimation is provided, comprising the steps of: 1) supplying uncorrected input data I.sub.i,u to a processing unit of a printer having a head with a plurality of heating elements; 2) obtaining density correction means M.sub.i,d for improving across-the-head uneveness according to the steps of: a) activating each heating element with power compensated input data, so that a same time-averaged power is generated in each heating element; b) measuring the printing density of pixels; c) estimating for each heating element the deviation .delta..sub.i of the density from a density aimed at by applying said power; d) calculating for each heating element a density correction means M.sub.i,d taking into account said deviation .delta..sub.i ; e) storing each of said density correction means M.sub.i,d ; 3) combining the respective uncorrected input data I.sub.i,u with the respective density correction means M.sub.i,d ; 4) providing the thus corrected data to the thermal head.

Abstract: There are provided a printing apparatus and a method of making a mask pattern for exposure by the use of the printing apparatus. A temperature of a thermal head is detected, and a plurality of split pulses formed by dividing a strobe pulse applied to the thermal head are sequentially applied with quiescent periods interposed therebetween. There is stored in advance pulse-applying data of settings of a cumulative period of pulse-applying periods over which the plurality of split pulses are respectively applied, a number of the split pulses, the split pulse-applying periods, and the quiescent periods, defined in a manner corresponding to values of the temperature of the thermal head. Appropriate pulse-applying data is read out according to the temperature detected, and application of the split pulses is controlled according to the appropriate pulse-applying data.

Abstract: A thermal printer has a thermal head, which includes plural heating elements arranged in a main scanning direction. The heating elements are driven while the thermal head and a color thermosensitive recording sheet are moved relatively in a sub scanning direction perpendicular to the main scanning direction. The heating elements apply bias heat energy and image heat energy to the recording sheet, thermally to record an ink dot on the recording sheet. The bias heat energy is determined to heat the recording sheet substantially to a temperature at which the recording sheet starts being colored. The image heat energy is determined in accordance with image data of a halftone image. Density correcting heat energy is additionally applied to the recording sheet through heating elements located in end positions in the thermal head. The heating elements of the end positions are so located that heat escapes therefrom fastest of the plural heating elements.

Abstract: A thermal printer includes a thermal print head having a plurality of heating elements for printing dots. A source of drive pulses operates respective heating elements. Each drive pulse is modulated to provide first and second periods of the drive pulse to selectively energize the respective heating element, the first and second periods defining a selected energy level. A memory stores the modulated drive pulses and supplies respective modulated drive pulses to the respective heating elements. A measuring circuit measures a heating factor of each heating element and provides a correction factor for each heating element based on the respective measured heating factor. The correction factors are combined to the respective drive pulses to alter the first and second periods, thereby reducing variations in dots due to differences in the heating factors of the heating elements.

Abstract: A correction apparatus for a thermal printer includes a memory for storing the deviation quantity of each heating element of a thermal print head or a temperature correction quantity, a first computer means for adding introduced image data and the deviation quantity wherein the gradation value of the image data is reflected when the heating element for printing the introduced image data is lower than the average resistance value or the current temperature, a second computer means for subtracting the deviation quantity wherein the gradation value of image data is reflected, from the introduced image data when the heating element for printing the introduced image data is higher than the average resistance value or the current temperature. Thus, the resistance correction according to the deviation of the heating element resistance and the temperature correction are realized by a simple circuit, thus reducing the memory capacity, which decreases the amount of required hardware.

Abstract: When setting up the thermal head, respective resistances of the heating elements of the thermal head are measured, and a difference between the resistance value of each heating element and the smallest resistance value is detected. A predetermined amount of resistance trimming energy for lowering the resistance of the heating element by a predetermined constant amount is applied to each heating element for a number of times which depends on the detected difference in the resistance of the heating element from the smallest resistance, to trim the resistance of the heating element down to the smallest resistance.

Abstract: A method of compensating for resistance tolerances in the printing of a multi-tone picture with a printing device which includes printing elements. Starting from a smaller number of required tone grades than the number of available tone grades, represented by energy values, printing is always effected with those available tone grades whose available optical density comes close to the required optical density. The differences between the required optical density and actually available optical density are added to form a mean deviation whose magnitude is minimized by selecting the corresponding available tone grade so that the created visual picture has the required optical density.

Abstract: A thermal print head including a line of electrically resistive heating points and electronic controls for controlling sequential connection to a power supply providing electrical current, and including for each heating point a countdown register which is loaded prior to printing each line of points with a value corresponding to the length of time during which a connection should be maintained with the corresponding heating point starting from a print authorization instant common to all of the points. According to the invention, the print head includes sensors for sensing the resistance of each heating point in real time, which sensors are connected to a circuit for regulating the amount of energy actually supplied to the corresponding point.