Abstract: According to the present invention, there is provided an ink jet recording apparatus for recording an image on a recording medium by discharging ink to the surface of the recording medium, wherein ink is reserved in an ink tank including a negative pressure generating member, such as an absorber and a foaming member, and a function of accurately detecting the residual quantity such that depletion to a predetermined level can be detected is realized. Light emitted by a photointerrupter is allowed to pass through a portion of a wall surface of the ink tank made of transparent plastic or the like which is transmissible with respect to detection light emitted by the photointerrupter to detect change in the light reflectance in the boundary portion between the wall surface and the ink absorber. In accordance with reflectance obtained in a case where no ink exists in the detected portion and that obtained in a case where ink exists, the residual quantity of ink can be detected.

Abstract: A color ink jet printing apparatus including a single suction mechanism having a capping member designed to cap any one of the printheads of the apparatus and carrying out a suction recovery of that capped printhead. A plurality of additional caps which are not associated with the suction mechanism are provided for capping the printhead. Various printing moving schemes are devised to provide quick and efficient positioning of selected printheads opposing the suction mechanism to speedily service that printhead.

Abstract: Disclosed are methods of determining and recording a synchronous signal pattern on a medium and also an information recording/reproducing device thereof. The method of determining an optimum synchronous signal pattern includes detecting correlation properties of a VFO pattern and a synchronous signal pattern with a matching filter by inputting the respective samples of the patterns to the matching filter; and determining the sample exhibiting an excellent correlation property as the synchronous signal pattern among the samples. The information recording method includes forming information by sequencing the VFO pattern, the determined synchronous signal pattern and (2, 7)-modulated data; and recording the information on a recording medium.

Abstract: A coding method and apparatus convert a data word of m.times.r bits into a code word of n.times.r bits (m<n) with regard to a predetermined number r. The basic data word length m is made two or three bits, basic code word length n is made five bits and the predetermined number r satisfies the relation 1.ltoreq.r.ltoreq.4 or 1.ltoreq.r.ltoreq.2 respectively, the data word of m.times.r bits is converted into a code word of 5r bits, and coding is performed in such a manner that the run number of "0"s is greater than four and less than 19, or greater than one and less than five respectively. Further, a decoding method and apparatus decode perform decoding in accordance with the logical expressionsY.sub.1 =X.sub.13 +X.sub.14 .multidot.(X.sub.19 +X.sub.20)+X.sub.9 .multidot.X.sub.10 .multidot.X.sub.15 +X.sub.9 .multidot.X.sub.10 .multidot.X.sub.11 .multidot.X.sub.12 .multidot.X.sub.13 .multidot..sub.14 +(X.sub.4 +X.sub.5).multidot.X.sub.10 .multidot.X.sub.15Y.sub.2 =X.sub.12 +X.sub.13 +X.sub.14 +X.sub.15 +X.sub.

Abstract: In a variable-length coding/decoding device, an r.multidot.m-bit data word is converted into an r.multidot.n-bit code word, where r is an integer having the relationship 1.ltoreq.r.ltoreq.r.sub.max, a basic data word length consists of a m bits (m is a positive integer), and a basic code word length consists of n bits (n is a positive integer), and each of data words of a variable-length run-length-limited code limiting the run number of bits of a first value (e.g., "o") between successive bits of a second value (e.g., "1") in a binary-coded bit string generated by concatenation of code words after the conversion to a value no smaller than d and no larger than k into a code word corresponding to thereto. At that time, an input data word is once coded into an r.sub.max .multidot.q-bit (q is a positive integer) code word, and then divided into r.sub.max blocks each consisting of q bits, and a code word in each of the blocks is coded to obtain a variable-length run-length-limited code word.