Abstract: A compact page holder device 2 for holding a book 80 open at some selected pages 92, 94. A bundle of book leaves 96 including one of the selected pages 92 extends forward through slot 54, over finger 20, back through slot 52, and under finger 10. A second bundle of book leaves 98 including the other selected page 94 is woven forward through slot 54, over finger 30, back through slot 56, and under finger 40. The interweaving of page holder fingers and book leaf bundles keeps the book and the page holder securely together despite casual handling. Pages may be turned while the page holder is holding the book open by slipping the pages out from under one end finger 10 and back under the other end finger 40.

Abstract: An impulse ink jet apparatus includes a plurality of lengthwise expandable piezoelectric transducers, each of the transducers varying the volume of a small compression chamber which is supplied ink from a reservoir by an ink flow path defined by a stack of thin plates held together upon the rigid forward face of a print head by a spring plate and U-clip.

Abstract: A method of fabricating an ink jet apparatus of the type having a plurality of variable volume chambers arranged in an array, each of the chambers adaptive to receive ink from a reservoir and including an orifice for ejecting droplets of ink-on-demand, is facilitated by utilizing a ganged array of transducer feet which are inserted into the chambers, joined to the respective transducer and unganged by lapping off an interconnecting web flushed with the forward face of the image head.

Abstract: A block of solid state ink is sequentially melted on demand as it is advanced against a heater plate. Sequentially melted ink flows into a continuously heated reservoir which supplies one or more ink jets.

Abstract: Ink jet apparatus for utilizing hot melt ink is provided, comprising a printing head and a reservoir for holding a supply of hot melt ink, the reservoir having a normally open port or fill tube with an end face residing within the volume of the reservoir, the end face being located at about the volumetric center of the reservoir. The reservoir is maintained with an ink volume of no more than about half of the reservoir volume, so that ink can not spill through the normally open port when the apparatus is tilted.

Abstract: Apparatus for cleaning contaminants from the face and orifice(s) of the print head of an ink jet printer includes a cleaning card having a foam strip secured across the front face of the card near its bottom edge, the upper portion of the card forming step-like protrusions from each lateral or side edge of the narrower lower portion of the card, the foam strip being saturated with a cleaning solvent, the lower portion of the card being adapted for insertion between a card guide and the face of said print head, causing squeezing of the foam strip for release of the solvent upon and wiping of the face of the print head and orifice(s) as the foam strip is moved thereagainst.

Abstract: An ink jet array comprises a plurality of ink jet chambers having inlets coupled to a reservoir. In order to promote priming, the reservoir is concave with the inlets to the chamber coupled into the reservoir in an area of reduced cross-sectional area.

Abstract: A device for forming and expelling a controlled quantity of liquid upon demand, such as an ink drop generating device, having a transducer deforming element for controlled deforming in response to an electrical signal, an orifice housing containing an orifice chamber which has an orifice opening at its front side and a relatively larger opening at its back side, the larger chamber opening being in direct communication with a liquid reservoir, the transducer deforming element and the orifice housing being closely positioned to provide direct interaction between the deforming element and the orifice chamber upon receipt of an electrical signal, the interaction causing generation of a liquid drop or other controlled quantity of liquid.

Abstract: A glass tube having a substantially planar wall with an orifice formed at one end of the tube which forms the chamber for an ink jet from which droplets of ink are ejected. A transducer is coupled to the substantially planar wall. The ratio of the modulus of elasticity of the tube and the modulus of elasticity of the transducer are substantially equal.

Abstract: A meter dial encoder for converting angular dial pointer shaft positions includes a single track code pattern having binary coded arcuate sectors rotated by the shaft. The pattern is rotated adjacent a pattern sensing assembly including a single circular row of sensing positions having associated sensors for producing a multiple bit binary code signal. The code signal is changed by only one bit for each arcuate pattern movement equal to one arcuate sector. Each shaft position is converted from a corresponding dial reading to a binary code signal having error checking capability. In one preferred form of the invention, an opto-electronic encoder includes a single illuminating source and a light guide arrangement to produce plural point light sources for each of plural light responsive sensors associated with each of the sensing positions. An alternative light guide arrangement optically couples each of the sensing positions to light sensors.

Abstract: Position measurement apparatus which utilizes a digital code to accurately determine the position of a movable body along a travel path. The digital code is selected to provide, for any N consecutive bits of the code, a bit pattern which is unique. Indicia defining the code, and a reader, are arranged for relative motion in synchronism with movement of the movable body. Translating apparatus converts each combination of N consecutive bits read by the reader into an address defining the location of the movable body relative to the travel path. In a preferred embodiment, the digital code is a maximum length digital code, which is conveniently generated by a polynomial generator. The bit length of the code, which is equal to 2.sup.N -1, is selected according to the length of the travel path and the desired resolution.