Abstract: A developing unit is disposed substantially directly under a toner chamber and receives toner through an opening formed in the toner chamber, and includes a developing roller, a supplying roller, and a developing blade. The developing roller supplies toner to an electrostatic latent image formed on an image bearing body. The supplying roller rotates in contact with the developing roller to supply the toner to the developing roller. The developing blade is in pressure contact with the developing roller to form a thin layer of toner on the developing roller. The developing blade is in contact with the developing roller at a first position spaced at least 5.84 mm from a second position at which the supplying roller is in contact with the developing roller. An agitating member may be added over the developing roller and supplying roller and between the first position and the second position.

Abstract: An image-forming apparatus includes a developing roller and a developing blade. The developing blade applies toner to the developing roller to form a thin layer of toner on the developing roller. The image-forming apparatus performs a printing operation that includes a paper-feeding period and a developing period following the paper-feeding period. The developing roller rotates relative to the developing blade at a first speed during the paper-feeding period and then at a lower second speed than during the developing period, thereby eliminating chance of white lines of occurring in a printed image. The developing roller may be rotated at a constant speed in each printing operation until the circumferential surface of the developing roller has traveled over a certain cumulative distance. When the surface has traveled over the first distance, the developing roller may be rotated at an increased speed over a certain distance.

Abstract: An image-forming apparatus includes a developing roller and a developing blade. The developing blade applies toner to the developing roller to form a thin layer of toner on the developing roller. The image-forming apparatus performs a printing operation that includes a paper-feeding period and a developing period following the paper-feeding period. The developing roller rotates relative to the developing blade at a first speed during the paper-feeding period and then at a lower second speed than during the developing period, thereby eliminating chance of white lines of occurring in a printed image. The developing roller may be rotated at a constant speed in each printing operation until the circumferential surface of the developing roller has traveled over a certain cumulative distance. When the surface has traveled over the first distance, the developing roller may be rotated at an increased speed over a certain distance.

Abstract: A developing unit is disposed substantially directly under a toner chamber and receives toner through an opening formed in the toner chamber, and includes a developing roller, a supplying roller, and a developing blade. The developing roller supplies toner to an electrostatic latent image formed on an image bearing body. The supplying roller rotates in contact with the developing roller to supply the toner to the developing roller. The developing blade is in pressure contact with the developing roller to form a thin layer of toner on the developing roller. The developing blade is in contact with the developing roller at a first position spaced at least 5.84 mm from a second position at which the supplying roller is in contact with the developing roller. An agitating member may be added over the developing roller and supplying roller and between the first position and the second position.

Abstract: An ink jet recording apparatus is provided with a black head and a plurality of color heads. The black head has a predetermined number of first orifices aligned at predetermined intervals (e.g. 0.0169 mm) in a sub scanning direction (direction in which a print medium travels). The plurality of color heads eject different colored ink drops. Each color head has the predetermined number of second orifices aligned in the sub scanning direction perpendicular to the main scanning direction. The second orifices of adjacent color heads are aligned in a main scanning direction perpendicular to the sub scanning direction.

Abstract: A dot data generator receives print data from a host apparatus and generates dot data from the print data. Dots have different diameters according to a gradation level. A drive frequency setting section sets a drive frequency in accordance with the print data. A drive signal generator generates a timing in timed relation with the drive frequency. A recording head is driven at the generated timing to form a plurality of dots on a print medium. An operation circuit determines a total drive time forming dots for each line in the main scanning direction. The drive frequency is set on a line-by-line basis in accordance with the total drive time. The timing may be delayed so that dots are formed always at accurate print positions irrespective of the scanning speed in the main scanning direction and in the sub scanning direction.

Abstract: An ink Jet head includes first base second base which are made of a piezoelectric material. The first and second bases are formed with a plurality of first and second grooves in their surfaces, respectively, and are formed with first and second electrodes on their surfaces between the first grooves, respectively. The first and second bases also includes side surfaces intersecting the surfaces of the first and second bases, respectively. The electrodes are spaced apart from the side surfaces. The second base is placed on the first base so that the grooves in the first base and the grooves in the second base communicate with each other to define ink pressure chambers. An insulating layer is formed on the inner walls of the ink pressure chambers. An orifice plate having orifices is bonded to the side surfaces so that the ink chambers communicate with atmosphere through the orifices.

Abstract: A method of manufacturing a print head is for use with an ink Jet printer. The print head includes a plurality of parallel ink pressure chambers defined by a plurality of walls and a cover bonded on the top surfaces of the walls. The method includes the steps of forming a plurality of parallel grooves in a piezoelectric element, the grooves being bounded by a plurality of parallel walls aligned in a row; and applying an adhesive either to the top surfaces of the walls or to a surface of a cover in registration with top surfaces of the walls, the adhesive being applied by screen printing, the adhesive being applied by moving a squeegee in a direction perpendicular to a direction in which the grooves extend.

Abstract: An ink jet head has a plurality of ink pressure chambers defined therein and a surface to which a plurality of ink pressure chambers open. An orifice plate having an orifice therein is bonded to the surface. When manufacturing the ink jet head, a coating of an insulating material is first formed on an inner wall of the ink pressure chambers and subsequently a re-dissolvable curingresin is applied to the ink jet head in an area from the inner walls to the surface. Then, the coating and the resin deposited on the surface are removed from the surface. Then, the resin deposited on the coating in the ink pressure chambers is dissolved to remove the resin from the inner wall. Finally, the orifice plate is bonded to the surface.

Abstract: An ink jet recording apparatus includes a printhead that ejects black ink drops and colored ink drops through a plurality of corresponding ink nozzles in accordance with print data. The printhead ejects ink drops when the printhead is moved to scan a recording medium in a forward direction and a reverse direction opposite to the forward direction. The forward and reverse directions are perpendicular to a direction in which the recording medium travels. A print data identifier separates the print data for a line into black print data and color print data. A print data selector supplies one of the black print data and color print data to the printhead when the printhead scans the recording medium in the forward direction, and the other of the black print data and color print data to the printhead when the printhead scans the recording medium in the reverse direction.

Abstract: An ink-jet head comprising a plurality of sidewalls each imparting a pressure pulse to an ink pressurizing cell by means of shear mode deformation, and a front wall having a plurality of orifices. The ink in the ink pressurizing cells is ejected from the orifices. Each sidewall comprises a first wall section, a first electrode disposed thereon, an anisotropic adhesive disposed thereon, a second electrode disposed thereon, and a second wall section disposed thereon. Width of the first electrode is narrower than width of the first wall section, and the upper surface of the first wall section has first side areas which are not covered by the first electrode. Width of the second electrode is narrower than width of the second wall section, and the lower surface of the second wall section has second side areas which are not covered by the second electrode.

Abstract: An ink jet recording apparatus is of the construction where information is printed by ejecting ink drops through orifices of an ink jet head mounted on a carriage. The ink jet recording apparatus includes a cap for closing the surface of the ink jet head in which the orifices are formed. The cap is adapted to move between a first position at which the cap is fully disengaged with the orifices, and a second position at which the cap is engaged with the orifices. The cap communicates with a suction mechanism which negatively pressurizes the cap when the cap is at the second position. The carriage, cap, and suction mechanism are controllably driven by a controller. The cap is provided with an engagement member, which may take the form of a sweep blade, attached to its tip for sweeping the surface in which the orifices are formed.

Abstract: An ink jet recording apparatus has at least one ink chamber having an orifice through which ink drops are ejected, each ink drop having a variable amount of ink and being ejected at a timing corresponding to the amount of ink; and a controller for causing said ink chamber to eject ink drops therefrom in accordance with print data. The ink drop has an amount of ink in accordance with the level of gradation of the print data and is ejected at a timing in accordance with the amount of ink. The ink chamber may includes a plurality of ink chambers, i.e., black, yellow, magenta, and cyan. A black ink chamber is located at a first distance away from the print medium and ejects black ink drops along line k1. Color ink chambers of yellow, magenta, and cyan are aligned in a plane parallel to the surface of the print medium and oriented so that the color ink drops are ejected toward the print medium along lines k1, k3, and k4, respectively.

Abstract: An ink jet printer has a print head mounted on a movable carriage. The print head prints by ejecting drops of ink. A cap is detachably mounted on the print head during non-printing periods. The cap moves together with the print head when the print head and the movable carriage move during the non-printing periods. The cap protects the print head by preventing accumulation of dirt and drying of ink. A cap holder detachably holds the cap. The cap holder carries the cap to the print head after printing ends, and carries the cap away from the print head before printing begins.

Abstract: An ink-jet head comprising a plurality of sidewalls each imparting a pressure pulse to an ink pressurizing cell by means of shear mode deformation, and a front wall having a plurality of orifices. The ink in the ink pressurizing cells is ejected from the orifices. Each sidewall comprises a first wall section, a first electrode disposed thereon, an anisotropic adhesive disposed thereon, a second electrode disposed thereon, and a second wall section disposed thereon. Width of the first electrode is narrower than width of the first wall section, and the upper surface of the first wall section has first side areas which are not covered by the first electrode. Width of the second electrode is narrower than width of the second wall section, and the lower surface of the second wall section has second side areas which are not covered by the second electrode.

Abstract: An impact printer has a print head in which demagnetizing coils are embedded in a filling compound. A resistor or Zener diode is connected in series between the print head and the printer's frame ground, to prevent current flow through the filling compound from causing corrosion of the demagnetizing coils, while permitting discharge of static charge from the print head to ground.

Abstract: According to a method of adjusting a head gap, a wire dot head is set to a predetermined position of a reference head gap; a printing pattern for detecting printing time is printed by a plurality of pins; reference printing times of respective pins are detected. Next, a test printing is performed with test printing dots previously selected from printing data, and printing time of the test printing is detected. Then, the thickness of the printing media is calculated based on the reference printing time and the printing time of the test printing. At that time, a rule of thumb in which the difference of the printing time corresponds to the difference of the head gap, is used. Then, a shift amount of the wire dot head is calculated for setting the head gap to an optimum value according to the thickness of the printing media, and gap shifting mechanism shifts the wire dot head by the shift amount. This leads to highly accurate detection of the head gap and improves printing quality thereof.

Abstract: A spring charge type wire dot printing head includes front cores 35 and rear cores 36 that are disposed in circles. The front and rear cores are used in pairs, and either one of these paired cores is wound with a coil 39 or 40. Since the inductance of the coils 39 and 40 can be increased, low electric current and low electric power consumption can be realized.

Abstract: A wire-dot print head has an armature having a tip to which a print wire is secured, a core provided in confrontation with the armature, a plate spring which is supported in a cantilever fashion and to which the armature is fixed, a permanent magnet assembly generating a magnetic flux to cause the armature to be attracted toward the core overcoming the resilient force of the plate spring, and a coil wound on the core to generate a magnetic flux upon energization to cancel the magnetic flux from the permanent magnet assembly, thereby to release the armature. The permanent magnet assembly includes a first permanent magnet of the samarium-cobalt type, and a second permanent magnet of the neodyminum-iron-boron type or the lanthanoid-iron-boron type.