Abstract: An undershot inking unit for a printing machine and a method for regulating ink distribution in a printing machine are disclosed. The undershot inking unit comprises an ink fountain roller communicating with an ink fountain, an inking roller, and an intermittent ductor roller for transferring ink from the ink fountain roller to the inking roller. In accordance with the present invention, the ductor roller is thrown onto the ink fountain roller at a rate that is independent of the printing speed of the printing machine, preferably, at a rate that is constant for all printing speeds. The disclosed apparatus and method alleviate the problem of ink fall-off in printing machines.

Abstract: An undershot inking unit for a printing machine and a method for regulating ink distribution in a printing machine are disclosed. The undershot inking unit comprises an ink fountain roller communicating with an ink fountain, an inking roller, and an intermittent ductor roller for transferring ink from the ink fountain roller to the inking roller. In accordance with the present invention, the ductor roller is thrown onto the ink fountain roller at a rate that is independent of the printing speed of the printing machine, preferably, at a rate that is constant for all printing speeds. The disclosed apparatus and method alleviate the problem of ink fall-off in printing machines.

Abstract: An undershot inking unit and associated method are disclosed. The undershot inking unit includes an ink fountain roller that is controlled independently of the printing speed of the printing machine, and in which the rotational contact angle of the distributor roller on the ink fountain roller is varied according to the printing unit speed. The method comprises controlling the rotational speed of the ink fountain roller independently of the printing speed of the printing machine; and varying the rotational contact angle of the intermittent ductor roller on the ink fountain roller according to the printing speed of the printing machine. In a preferred embodiment, the apparatus includes two coaxial cams rotatably adjustable with respect to each other. Each cam includes a predominant circumferential contour and a subordinate circumferential contour.

Abstract: A semishell-shaped gripper apparatus for sheet-fed printing machines includes a gripper of low mass, which is fastened without play on the gripper shaft and minimizes the sliding of the gripper tip on the printing carrier. This is achieved by having the gripper finger surround the gripper shaft in such a way that separate effective engagement surfaces are formed. The effective engagement surfaces are disposed on the gripper shaft with frictional engagement and, in conjunction with the resultant force, form a triangle of forces. The gripper holder has a depression running parallel to the gripper shaft connecting to the lower edge of a web on the gripper finger in a releasably positive-locking manner. The gripper tip has a raised holding surface which has tapering radii on its periphery.

Abstract: An undershot inking unit and associated method are disclosed. The undershot inking unit includes an ink fountain roller that is controlled independently of the printing speed of the printing machine, and in which the rotational contact angle of the distributor roller on the ink fountain roller is varied according to the printing unit speed. The method comprises controlling the rotational speed of the ink fountain roller independently of the printing speed of the printing machine; and varying the rotational contact angle of the intermittent ductor roller on the ink fountain roller according to the printing speed of the printing machine. In a preferred embodiment, the apparatus includes two coaxial cams rotatably adjustable with respect to each other. Each cam includes a predominant circumferential contour and a subordinate circumferential contour.

Abstract: A method of correcting tooth system errors in a gear pairing in which one of the gears is mounted on a component to be driven. The mounted gear is first non-positively supported on the shaft of the component to be driven with a relatively small clearance between the gear and shaft, the error in the angle of gear rotation then is measured by a separate measuring facility in a single-flank rolling test, and the gear is radially displaced to correct for the error in the angle of rotation. The gear then is positively connected to the shaft without clearance between the gear and shaft by a plastic layer interposed between the shaft and an annular groove in the mounting bore of the gear.

Abstract: A conveying cable for conveying sheets includes a suction chamber with a supporting surface defining a shallow groove having a plurality of suction openings therein over which a perforated suction belt moves. A plurality of vent openings separately communicating with atmosphere are disposed adjacent the belt edges to prevent the sheets from being sucked against the table surface. The perforations in the suction belt preferably take the form of staggered slots which leave imperforate zones free along the center and adjacent the edges of the belt to help reduce undesirable belt stretching and the suction openings in the supporting surface increase in size adjacent the delivery end of the table.

Abstract: In order to improve mechanical positive synchronization in a sheet-fed printing machine between gripper carriages guided in wave-like fashion through printing units on endless chains and the associated impression cylinder, the impression cylinders (1) have twice the diameter of the plate and blanket cylinders (2, 3). Sprocket wheels (34), also of twice the diameter of the blanket cylinders, are fixed on the ends of the double-size impression cylinders (1) and on them there are disposed two diametrically opposite gripper carriage locating and fixing devices (24-32) which are adjustable both radially and tangentially and which can also be used to bring the different printing plates into register with one another on the printed sheet (38).

Abstract: To obviate local differences in heat expansion in the ink duct, ink metering means and ductor roller, and to temper the printing ink, stabilize the ink-damping agent emulsion and protect the ductor roller from corrosion, the ink duct includes a heat insulating material secured to underside of the duct body and a mid-section portion of the duct body side facing the ductor roller is supplied with a warm air flow from the printing press, boosted by a plurality of fans.

Abstract: To provide for fine-adjustment of the relative angular position of a driven body of rotation, such as a plate cylinder (1) of a printing machine, and having a driven shaft (21, 41) with respect to a driving shaft (9, 40), an axially shiftable intermediate shaft portion (14, 53) is positioned between the driving shaft (9, 40) and the driven shaft (21, 41) and the body of rotation, respectively. An elastic coupling structure (16, 24; 55, 57), for example a composite stacked leaf spring, and having the characteristic of being circumferentially stiff but axially flexible, couples the intermediate shaft, for axially shifting movement, between the respective shafts. Preferably, two such elastic coupling structures are provided.

Abstract: A clamping gripper for sheet-fed rotary printing presses wherein tensions produced in the paper by adhesion forces of the blanket do not react in run-on shifts of the center of a main gripper member mounted for rotation with a fit clearance on the gripper shaft. A spring is so disposed, and the bearing plane and the gripper support surface are so inclined relative to one another, that the resultant force due to the spring force, thrust and bearing load intersect the gripper finger at the transfer point.

Abstract: A sheet gripper assembly for a sheet-fed rotary printing press having a gripper tip with a non-resilient pressure element fastened to the gripper tip by a layer of resilient material, the pressure element having a central protuberance, extending through the resilient layer, upon which the gripper tip bears.

Abstract: In a printing machine having means for adjusting the circumferential, axial and diagonal register of a plurality of plate cylinders on which printing plates are secured, wherein each plate cylinder is mounted on a shaft for rotation and each printing plate has register markers disposed thereon outside of its respective printing and inking zone, the improvement comprising: a register marker detection system comprising at least one illuminating means disposed on one side of each plate for generating and projecting light to illuminate said register markers; at least one photo-detecting means disposed on the other side of each plate for periodically detecting said light projecting through the register markers as the cylinder rotates the printing plate and for generating measurement signals in response thereto; and circuit means connected to said photo-detecting means for generating signals to control said cylinder register adjustment means; said register markers comprising at least first and second accurate-regis

Abstract: A resilient sheet gripper for a sheet-fed rotary printing press having a gripper finger resiliently connected to a clamping member secured to a gripper shaft is provided including prestressed spring strips for connecting the gripper finger to the clamping member with each spring strip having articulation points disposed along a line passing substantially through the axis of the gripper shaft.

Abstract: A resilient sheet gripper for a sheet-fed rotary printing press having a clamping member secured to a gripper shaft and a pivoting gripper finger resiliently connected to the clamping member by an adjustable compression spring is provided, including eccentric bushings mounted on the gripper shaft, the gripper finger being journaled thereon, so as to impart a positive gripper closing movement substantially perpendicular to a gripper support.

Abstract: A resilient sheet gripper for a sheet-fed rotary printing press having a gripper shaft and a gripper finger disposed in a recess of a cylinder of the printing press and including an asymmetrical four-pivot mechanism having the gripper finger as one of its links for governing the motion of the gripper finger and ensuring perpendicular closing of the tip thereof with respect to a sheet engaged on a gripper support at the edge of the recess.

Abstract: A chain conveyor for the delivery device of printing presses has gripper systems (1) being carrier directly by the endless conveying chains (2). The gripper system (1) is embodied by a unitary aluminum basic member (6). A steel tube (9) is cast into the basic member (6) at its center of gravity and over its whole length and optimizes the flexural and torsional rigidity of the gripper system (1).

Abstract: A device for measuring pressure between two cylinders of a press includes a plate mounted to the end of a journal of one of the cylinders in a position perpendicular to the cylinder axis, and a set of electrical proximity sensors measuring the tilting of the plate as a result of slight bowing of the cylinder in response to changes in applied pressure. The proximity sensors are disposed at diametric locations at a substantial radius with respect to the cylinder axis, and an electrical circuit combines signals from the proximity sensors in such a way as to cancel signals generated in response to axial shifting of the cylinder to which the plate is mounted. Preferably the sensors are mounted in the common plane including the two cylinders and a set of sensors is disposed on each side of the plate. Additional sensors can be used to independently measure the pressure applied by a third cylinder engaging the cylinder to which the plate is mounted.

Abstract: A force or movement sensor is disposed on or proximate to an impression cylinder of a sheet-fed printing machine in order to sense the printing pressure. The sensor is sampled in synchronism with the rotation of the impression cylinder and the feeding of the sheets in order to detect a first pressure signal when pressure is applied to the fed sheets, and to detect a second pressure signal when the impression cylinder is relieved of the printing pressure. The differential value of the first and second pressure signals is displayed as an output or is evaluated by a pressure control system. As a result, static and quasi-static disturbances are suppressed. The mesurement is not affected by wear of the cylinder bearings or journals, variations in machine speed, and zero-point shift in the sensor and its associated electronics. These disturbances are further suppressed by averaging or accumulating samples over sample intervals and over a number of revolutions of the impression cylinder.

Abstract: A rotary printing press having first and second cylinders in rolling engagement, the first cylinder being rigid and the second cylinder being resiliently covered, both of the cylinders having a longitudinal groove defining a gap in the cylinder surface, the gaps being rotated in opposed synchronism with one another.