Abstract: Print codes supplied from a host computer are received and analyzed to generate print data for the individual colors, and the generated print data are stored in print buffers corresponding to the colors. The print data corresponding to yellow ink with high lightness is expressed by binary data, and is printed by one dot per pixel by a single print scan. The print data corresponding to each of the remaining high-density (thick) inks is expressed by multi-valued data having a larger number of bits than the yellow data, and is printed by a plurality of print scans.

Abstract: There is provided a printing registration method for stably performing printing registration in bi-directional scanning by a print head in a printing apparatus or printing registration between a plurality of print heads with high accuracy. In complementary printing by the bi-directional scanning by the head, a plurality of patterns are printed while printing starting timings are shifted by predetermined quantities with respect to reference dots (dots formed by forward scanning). In the pattern, an area factor defined by the dots formed by the printing is varied according to the shifting. The plurality of patterns are optically read as an average density. The timing corresponding to a point where the read average density is highest can be determined as a printing registration condition. Furthermore, an optical sensor used for the reading is located at a position where an S/N ratio is stable with respect to fluctuations in distance from the object to be read, thus achieving stable reading.

Abstract: A paper feed operation is performed by a width less than one pixel (½) in addition to an integer multiple number of pixels (n/2) with respect to a basic number of pixels inherent to an ink jet recording apparatus having a multi nozzle head having n nozzles. When a plurality of pixel recording operations are performed for a single pixel region, ink dots land within a distance less than one pixel unit (½). Thus, a variation in ink surface density on a recording sheet in an overlapping print operation is reduced, thereby efficiently increasing the image density, and preventing blurring by promoting absorption and evaporation of an ink to and from a paper sheet.

Abstract: There is provided an inkjet printing head carrying a sub-tank from which accumulated gases can be easily discharged. The inkjet printing head includes a sub-tank which has a movable section constituted by a deformable film sheet, a spring for generating a negative pressure, and a supply/discharge channel for supplying ink and discharging accumulated gases. The sub-tank is intermittently supplied with ink from a main tank and reserving the ink. The supply/discharge channel is provided in a position where it does not interfere with the movable section and the spring, e.g., in a frame of the sub-tank. The supply/discharge channel is preferably formed in an upper part of the sub-tank, e.g., a ceiling section of the sub-tank.

Abstract: In complementarily printing by bi-directional scannings of a head or by a plurality of print heads, first patterns and second patterns including reference dots for example, dots formed by a forward scan of the bi-directional scannings or by one of the plurality of print heads and dots each having the different direction of shifting of relative printing positions to the reference dots are printed in corresponding to the plurality of shifting amounts. These first and second patterns have the similar characteristics of a change in density. The difference is only that their characteristics in density change are inverted according to the direction of shifting. The intersection point of these two characteristics in density change is obtained as a position for adjustment where dot-formed positions match.

Abstract: An apparatus that includes a recording head having a plurality of recording elements arranged in a first direction is scanningly moved relative to a recording material in a second direction which is different from the first direction. The apparatus includes a motor driver for scanningly moving the recording head to the recording material in the second direction and a CPU/MPU for controlling driving of the recording head such that while scanningly moving the recording head in the second direction, the recording is effected such that a recording band region which extends into a second region and which is recorded using part of a continuous recording element and a non-recording band region which is not recorded, appears alternately, and by a different scanning movement, the non-recording band region is recorded. The recording band region and the non-recording band region have the same size.

Abstract: In a structure of an ink tank having a deformable sheet that constitutes the tank and a spring for imparting a negative pressure, unstableness of the negative pressure attributable to the deformation of the sheet as a result of ink consumption is prevented. For this purpose, a plate-like member is joined to a top section of the sheet formed in a convex shape, and the spring for generating the negative pressure in the tank is mounted to the same member. This makes it possible to maintain a high volume ratio of the ink tank and to achieve stableness of the negative pressure by adequately regulating the deformation of the sheet when the sheet is displaced in the direction of retracting toward the interior of the tank as a result of a reduction of the amount of ink in the tank.

Abstract: There is provided a printing registration method for stably performing printing registration in bi-directional scanning by a print head in a printing apparatus or printing registration between a plurality of print heads with high accuracy. In complementary printing by the bi-directional scanning by the head, a plurality of patterns are printed while printing starting timings are shifted by predetermined quantities with respect to reference dots (dots formed by forward scanning). In the pattern, an area factor defined by the dots formed by the printing is varied according to the shifting. The plurality of patterns are optically read as an average density. The timing corresponding to a point where the read average density is highest can be determined as a printing registration condition. Furthermore, an optical sensor used for the reading is located at a position where an S/N ratio is stable with respect to fluctuations in distance from the object to be read, thus achieving stable reading.

Abstract: For eliminating waste of ink and achieving high charging efficiency with a reduced charging time where a printing head is equipped with a second tank for reserving a predetermined amount of ink and a supply system is configured to supply ink from a first tank to the second tank intermittently, a second tank having a variable internal volume is provided, and the internal volume is varied to cause the second tank itself functions as an actuator for charging ink and performing a venting process. Specifically, the internal volume is forcibly reduced to cause a reverse flow of a gas residing in the second tank along with ink into the first tank, which makes it possible to generation of waste ink that is released to the outside. A normal charging operation can be completed simply by causing a change in the opposite direction (the direction of increasing the internal volume).

Abstract: In a structure which includes a second tank for reserving a predetermined amount of ink to be supplied to a printing head and in which a supply system is configured such that ink is intermittently supplied to the second tank from a first tank, a high charging efficiency to and shortened processing time for charging the second tank, and high overall usability of ink are achieved. In an orientation upon using the printing apparatus, a port of a channel located at the second tank side for supplying ink from the first tank to the second tank is arranged relatively high position and an outlet port for supplying ink from the second tank to the head is arranged relatively low position in relation to the direction of gravity, and a port of the channel located at the first tank side is arranged at the bottom of the first tank.

Abstract: A structure which includes a container for reserving a predetermined amount of ink to be supplied to a printing head and in which a supply system is configured such that ink is intermittently supplied to the container from an ink tank as an ink supply source makes it possible to reduce the time for charging the container with ink. A member for holding ink and generating a negative pressure originating from an elastic force is provided in the container. With connecting the tank and the member, the pressure in the container is reduced to cause the member to expand, thereby introducing ink into the same. This introduction is stopped by regulating the expansion with a displaceable unit. A negative pressure is generated in the member by canceling regulation by the unit to put it in equilibrium with an ink meniscus holding ability of the printing head.

Abstract: An ink jet printing apparatus is provided which can prevent a discharged paper-induced smear efficiently with a simple construction. To achieve this objective, the ink jet printing apparatus of this invention determines, based on an amount of ink ejected per unit area onto a preceding print medium last discharged to the discharge position by the discharging section, a required time duration that needs to elapse before a subsequent print medium being discharged toward the discharge position is allowed to contact a predetermined area of the preceding print medium and then controls a printing speed on the subsequent print medium so that the subsequent print medium will not contact the predetermined area of the preceding print medium within the time duration determined.

Abstract: A printing apparatus for performing printing on a printing medium using a print head includes an electrical-power-distribution determination unit for determining a state of concurrence of respective control units for a sheet feeding mechanism, a sheet conveying mechanism, a carriage mechanism and the like and supplying optimum electric power at that time, even if a dedicated motor is provided for each of the mechanisms. For example, when the carriage mechanism is operating and the sheet conveying mechanism is performing driving, low-speed sheet feeding is performed. When neither the carriage mechanism nor the sheet conveying mechanism are performing driving, high-speed sheet feeding is performed. By thus optimizing distribution of electric power for a plurality of driving sources of the printing apparatus, high-speed recording with low electrical power can be realized.

Abstract: The present invention reduces a difference in speed between a main drop section and a tailing section of a ejected ink droplet by heating a front heater and a rear heater provided for one nozzle with a predetermined time lag and thus, the ink dot formed from the main drop section and the tailing section on a printing medium can be more approximate to a circle. Thereby, it is possible to prevent print quality from being degraded by the tailing section separated from the main drop section of the ink droplet ejected from an ink jet printing apparatus of serial type.

Abstract: To reduce the number of simultaneously driven printing elements so that the instantaneously flowing current is restricted in a printing system for completing an image by repeating the printing scan a plurality of times in the same printing area while applying random mask thereto. For this purpose, a mask of a predetermined size is structured as a thinning pattern in which data are arranged randomly, the data being for determining whether or not the respective ink ejection openings in a printing head are to be driven when the printing head repeats the scan a plurality of times in the same printing area of a printing medium. When forming an image, the printing elements concerned with the printing operation in the same printing area are divided into a plurality of sections, and the thinning patterns complementary to each other are applied to the respective sections during the respective printing scans.

Abstract: A print apparatus that, without significantly reducing an overall printing speed, allows a reduction in uneven densities due to the discharge time difference between black ink and color inks, which occur particularly at both ends in a scanning range and which are caused by the printing by bidirectional scanning of print heads, and enables high image-quality printing to be realized. In this print apparatus, one band is divided into plural areas in a main scanning direction, the dot numbers of black ink and color ink imparted to respective areas are counted. If there are any areas where the dot numbers of both black and color exceed respective threshold values, the area number is counted, and if the number exceeds a predetermined number, the print mode is switched from bidirectional printing to a unidirectional one, upon determining that there is a high probability of occurrence of the above-described uneven densities.

Abstract: In a complimentary printing by bi-directional scanning of a head or by a plurality of heads, a plurality of patterns in which a print start timing is shifted by a predetermined amount are printed with respect to a reference dot formed by the forward scan of the bi-directional scanning or by one of the plurality heads. In these patterns, an area factor by the dots formed by printing of the patterns is designed to be varied depending upon shifting amount. An average density is read from each of the plurality of patterns, optically. The timing at which the maximum one among average densities read from the patterns is obtained, can be set as the printing registration condition. Further, before the above reading operation, an optical sensor used for this operation is calibrated, for improving accuracies of the reading and the registrating.

Abstract: An ink-jet recording apparatus, using an ink-jet head for ejecting ink supplied from an ink tank for storing ink and performing recording by ejecting ink from the ink-jet head based on recording data, the ink-jet recording apparatus performing recording by receiving the recording data transferred from a host through a signal line in a state that the ink-jet recording apparatus is connected to the host by the signal line. The apparatus obtains information as to a remaining amount of ink stored in an ink tank and a used amount of the ink-jet head, and stores the information so-obtained. A controller processes recording data transferred from the host and controls recording by the ink-jet head. According to one aspect, the controller transfers information stored in the memory to the host through the signal line according to a command input through the signal line.

Abstract: A first printing pattern is formed for a patch by means of a paper feed upstream side part of a black head. Then, a second printing pattern is formed for the patch by means of a cyan head in the following scans, and density of the patch is read by a reflection optical sensor in a scan after the completion of both patterns.

Abstract: The object of the present invention is to provide an ink jet printing apparatus which can realize both a high speed printing and a high quality printing without color deviations when each of the print areas is printed in a plurality of scans by a plurality of print heads ejecting different kinds of ink.