Benq Corporation

Acer Communications and Multimedia Inc.

Hi-touch Imaging Technologies Co., Ltd.

Yu-Fan Fang

Chih-Hung Kao

Kuang-Huei Huang

A method is provided to increase the gray level resolution of a thermal print head. The thermal print head includes a plurality of heaters which are used to heat color dye so as to deposit the color dye on a paper to form a line image. The line image contains a plurality of pixels, each formed by one heater. When generating a pixel, a pulse sequence is fed to one heater to control the heater&Prime;s heating period. The pulse sequence contains first and second portions. The first portion contains a plurality of consecutive pulses which is used to generate a first gray level. And the second portion contains at least one empty pulse period followed by at least one pulse which is used to generate a second gray level. The combination of the first and second gray levels will determine the gray level of each pixel of the line image.

Printing method for interpolating gray levels

An ink jet printing device has an ink jet printing head capable of moving back and forth along a print track to perform a printing job. The ink jet printing head has a plurality of nozzles and corresponding driving units. The servicing method has the steps: (1) recording status of each driving unit; (2) determining a service job corresponding to each individual driving unit with a predetermined rule according to the corresponding status of each driving unit when the ink jet printing head needs to be serviced, and (3) driving each driving unit to perform the corresponding service job.

Method and device for balanced service of ink jet nozzles

A method and apparatus for use in inkjet printing. The apparatus includes a memory, a heat accumulation calculation device, and an image separating device. The memory is used to store a heat weighting look-up table. When data representative of the image is fed into the heat accumulation calculation device, a heat weighting for the image can be calculated according to the heat weighting look-up table, which can be used to determine the degree of heat accumulation during printing. The image separating device then outputs pieces of image data representing sub-images according to the heat weighting for the image. Finally, the image is formed by printing the sub-images successively according to the pieces of image data. In addition, for some regions where serious heat accumulation is predicted, the densities of the pixels to be printed within the regions can be adjusted to reduce the degrading effect on the printing quality due to the heat accumulation during printing.

Method and apparatus for use in inkjet printing for reducing thermal accumulation during inkjet printing

A driving circuit drives an ink jet print head in a printing device. The ink jet print head has ink jet cells and heating elements corresponding to the ink jet cells. The driving circuit has a driving signal generator that provides two different driving signals to heat the ink jet cells. The first driving signal heats cells intended for jetting ink with sufficient energy so that they do jet ink. The second driving signal heats cells not intended for jetting ink with insufficient energy so that they are heated without jetting ink.

Driving circuit capable of maintaining heat equilibrium of a print head nozzle

A print head apparatus capable of temperature sensing is provided. The print head apparatus includes an ink ejector coupled to an enabling signal and a selection signal for selecting the ink ejector. The ink ejector includes a nozzle, a heating module for selectively heating ink in the ink ejector so that ink droplets are ejected from the nozzle, and a temperature sensing module for selectively producing a measured temperature signal indicative of a temperature of the ink in close proximity to the nozzle. When the enabling signal is active, and the selection signal is active and indicates that the ink ejector is selected, the heating module heats up the ink in the ink ejector so that the ink droplets are ejected from the nozzle. When the selection signal is active and indicates that the ink ejector is selected, the temperature sensing module outputs the measured temperature signal indicative of the temperature of the ink in close proximity to the nozzle. By applying the invention to an inkjet print head with a plurality of nozzles, the temperature of each nozzle can be obtained selectively.

Print head apparatus capable of temperature sensing

A control circuit for driving a print head of a printing apparatus is disclosed. The print head has a plurality of heating elements and a plurality of ink chambers. Each ink chamber stores ink and has a nozzle. The control circuit includes a thermometer for measuring a temperature of the ink chambers, and a processor for generating a heating signal according to printing data transmitted from the printing apparatus to drive heating elements to heat ink chambers corresponding to nozzles which will jet ink. The processor also generates a pre-heating signal to drive the heating elements according to the temperature measured by the thermometer. When necessary, the processor will generate the pre-heating signal in addition to generating the heating signal so as to provide additional energy to drive the heating elements corresponding to the nozzles which will jet ink.

Control circuit for driving a print head of a printing apparatus

A method for driving an ink jet print head of a printing apparatus is disclosed. The ink jet print head includes a plurality of ink cells for containing ink, Each ink cell has a nozzle and a heating element. The method includes calculating an index of each nozzle which will jet ink in an array, corresponding indices of all nozzles which will jet ink in the array to heat-accumulation weightings according to a heat-accumulation weighting table, using the calculation module to calculate a total weight of the array using the heat-accumulation weightings of all the nozzles which will jet ink in the array, and using a driving module to provide energy to heating elements corresponding to the nozzles which will jet ink according to the total weight of the array.

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Taipei, Taiwan

Yu-Fan Fang