Abstract: A printer control unit (3) is described for controlling the size of droplets emitted by a nozzle of a printhead (8) in an inkjet printer. The control unit (3) receives information about an image to be printed by the printer, for example from a raster image processor (5), the information including droplet size information regarding the size of droplet required to be emitted by the nozzle to print the image. Print parameter information for printing the image is determined on the basis of the received droplet size information, the print parameter information including information for use in setting the printer such that droplets emitted by the nozzle during the printing of the image have the required droplet size.

Abstract: The application describes a method and apparatus for controlling surface finish in the printing of a substrate in a plurality of passes using a curable print material and an ink jet printer having a radiation source. A first set of passes is carried out, including depositing ink on the substrate and emitting radiation from a radiation source toward the deposited ink. The emitted radiation applies a dose of radiation in a first range. A second set of passes is then carried out to deposit ink on the substrate. Further radiation is emitted from a radiation source toward the deposited ink, the emitted radiation applying a dose of radiation in a second range different from the first range.

Abstract: A substrate support apparatus for a printer is described. The apparatus includes a table having a support surface for supporting a substrate during printing, the support surface including a plurality of substrate apertures. A negative pressure can be applied to the substrate apertures to hold the substrate to the table during printing. The apparatus further includes a plurality of mask apertures, and a negative pressure can be applied to the mask apertures to hold a mask to the support surface. By arranging for the pressure to be applied to the substrate apertures and mask apertures independently, the mask can be held to the table during loading and unloading of the substrate.

Abstract: Apparatus is described for handling a print substrate in a printer. In examples described, the substrate is a web, for example a continuous web. A web support device is provided for supporting the web in a printing region and a web transport device is adapted to move the web forwards and backwards in the printing region. In examples described, multipass printing is carried out.

Abstract: A method is disclosed of printing an area of a substrate in a plurality of passes using curable ink, the method comprising depositing a first pass of ink on the area, partially curing ink deposited in the first pass, depositing a second pass of ink on the area, and fully curing the ink on the area. The method finds particular application in the field of inkjet printing, and can afford the advantage of better wetting of ink on the substrate deposited by a previous pass and reducing the problem of ink spreading.

Abstract: An inkjet printer (10) is described which includes two substrate support beds (30, 40). The printer can print onto a first substrate on one of the support beds (30) while a second substrate is loaded onto and/or unloaded from the second support bed (40). In this way, the printing operation can be made more efficient and the throughput of the printer can be improved.

Abstract: A method of curing radiation-curable fluid is described. In one example, the method includes emitting radiation from an array of light-emitting diodes towards ink to be cured. LEDs are cheap, light weight, highly efficient in their conversion of electrical power, and give effectively instant switching to full power. Another advantage is that the emission spectrum of an LED is sharply peaked around the nominal frequency. Thus LEDs give several advantages over conventional radiation sources such as mercury lamps. A low oxygen environment is preferably provided at the radiation source to accelerate the curing reaction. Also described are inks which are specially formulated to respond to the radiation emission spectrum of an LED.

Abstract: A multipass large format flat bed inkjet printer (1) for printing an image on a substrate is described. In examples described, the printer (1) has a print carriage (8) for supporting an array of printheads (18) adjacent the substrate (6) during printing; a bed (4) for supporting the substrate (6) during printing; and a movement mechanism (5) for providing relative movement of the print carriage (8) and the substrate (6) in a print direction during a print pass. The print carriage (8) is such that the width of the array of printheads (18) transverse to the print direction is at least substantially the full width of the image. In examples described, the printheads (18) provide an array of nozzles (22) which is substantially continuous across the array of printheads (18).

Abstract: An ink jet printing apparatus for printing on a moving substrate (16) is described. The apparatus comprises ink jet printheads (4) for printing on a surface of the substrate, a plurality of rollers (12, 14) arranged to move the substrate (16) relative to the printheads (4), and a pressure source (22). The pressure source (22) is arranged to apply a negative gauge pressure (32) to the substrate (16). The application of the pressure can hold the substrate flat and can reduce undesired movement of the substrate relative to the rollers (12, 14). The apparatus allows for high quality full colour images to be printed onto substrates in a single pass using an ink jet printer.

Abstract: A method of curing radiation-curable fluid is described. In one example, the method includes emitting radiation from an array of light-emitting diodes towards ink to be cured. LEDs are cheap, light weight, highly efficient in their conversion of electrical power, and give effectively instant switching to full power. Another advantage is that the emission spectrum of an LED is sharply peaked around the nominal frequency. Thus LEDs give several advantages over conventional radiation sources such as mercury lamps. A low oxygen environment is preferably provided at the radiation source to accelerate the curing reaction. Also described are inks which are specially formulated to respond to the radiation emission spectrum of an LED.

Abstract: A printer control unit (3) is described for controlling the size of droplets emitted by a nozzle of a printhead (8) in an inkjet printer. The control unit (3) receives information about an image to be printed by the printer, for example from a raster image processor (5), the information including droplet size information regarding the size of droplet required to be emitted by the nozzle to print the image. Print parameter information for printing the image is determined on the basis of the received droplet size information, the print parameter information including information for use in setting the printer such that droplets emitted by the nozzle during the printing of the image have the required droplet size.

Abstract: A printing speed for printing an image using an inkjet printer is determined. Information regarding a measure of the nozzle firing quality of the printer as a function of printing speed and in relation to an image attribute is determined. The image to be printed is analysed in respect of the image attribute and the information regarding the measure of the nozzle firing quality is used to determine an optimum printing speed for printing the image. Thus a determination may be made as to how fast a particular image may be printed using a particular printer arrangement without unacceptable loss of print quality of the image. Also described is a method of determining printing instructions for printing a plurality of images in which a printing speed for each image is determined, and printing instructions for printing the plurality of images is determined so as to increase the overall efficiency of printing the plurality of images.

Abstract: In an inkjet device for containing, degassing and supplying ink, gas is supplied to a container for the ink so that the gas bubbles through the ink in the container. A controller controls a gas supplying means to operate in at least two modes including a degassing mode in which the pressure in the container is at a degassing pressure and the gas supplying means is controlled to supply the gas at a pressure above the degassing pressure to bubble through the ink, and an ink supplying mode in which the container is at an ink delivery pressure. In preferred examples, the ink container is arranged for supplying ink to a printhead; using the degassing arrangement, the formation of bubbles in the ink at the printhead can be reduced.

Abstract: A printing apparatus is adapted for printing on a printing surface of a three-dimensional object 12. The apparatus comprises an inkjet printhead 14 having a plurality of nozzles, and being operative to effect relative movement of the printhead and the object, during printing, with a rotational component about an axis of rotation and with a linear component, in which the linear component is at least partially in a direction substantially parallel with the axis of rotation and wherein the nozzle pitch of the printhead is greater than the grid pitch to be printed onto the printing surface in the nozzle row direction. In preferred examples, a substantially helical path is printed on the surface and improved ink jet printing of three dimensional objects can be achieved.

Abstract: An ink jet printing apparatus for printing on a moving substrate (16) is described. The apparatus comprises ink jet printheads (4) for printing on a surface of the substrate, a plurality of rollers (12, 14) arranged to move the substrate (16) relative to the printheads (4), and a pressure source (22). The pressure source (22) is arranged to apply a negative gauge pressure (32) to the substrate (16). The application of the pressure can hold the substrate flat and can reduce undesired movement of the substrate relative to the rollers (12, 14). The apparatus allows for high quality full colour images to be printed onto substrates in a single pass using an ink jet printer.

Abstract: A method of curing radiation-curable fluid is described. In one example, the method includes emitting radiation from an array of light-emitting diodes towards ink to be cured. LEDs are cheap, light weight, highly efficient in their conversion of electrical power, and give effectively instant switching to full power. Another advantage is that the emission spectrum of an LED is sharply peaked around the nominal frequency. Thus LEDs give several advantages over conventional radiation sources such as mercury lamps. A low oxygen environment is preferably provided at the radiation source to accelerate the curing reaction. Also described are inks which are specially formulated to respond to the radiation emission spectrum of an LED.

Abstract: A method is disclosed of printing an area of a substrate in a plurality of passes using curable ink, the method comprising depositing a first pass of ink on the area, partially curing ink deposited in the first pass, depositing a second pass of ink on the area, and fully curing the ink on the area. The method finds particular application in the field of inkjet printing, and can afford the advantage of better wetting of ink on the substrate deposited by a previous pass and reducing the problem of ink spreading.

Abstract: A digital printer has a printhead (10) for printing on a substrate and an encoder (14) which emits pulses (122) to indicate the relative distance moved by the printhead. A timer device for the digital printer emits output print pulses (151) for effecting printing and a count module (130) for receiving pulses (122) from the encoder (14) and emitting a print signal after a predetermined number of encoder pulses (122) to effect the emission of the output print pulse. The timer device is adapted to add a delay between the emission of the print signal and the emission of the output print pulse (151). In examples described, the pitch of the printed droplets can be closely controlled.

Abstract: A pressure regulation system for an inkjet printer includes a chamber for containing ink, a level sensor to measure the level of ink contained in the chamber, a pressure source for providing a fluid at a controlled positive or negative gauge pressure, and a pressure control device to control the pressure source. An ink supply regulating device regulates the flow of ink and an ink flow control device controls the ink supply regulating device based on an output of the level sensor. The pressure regulation system can be mounted close to the printhead.

Abstract: A method of and apparatus for producing a mixed batch of consumer products without the use of a mechanical mixer to carry out the mixing. An image sequencing means is provided which sequences images to be printed by a digitally-controlled printhead. Varying images are placed on consumer products or parts thereof—e.g. cigarette cards—as those products or parts of products pass under the printhead at a point in the production line. The consumer products, once assembled, are packaged directly from the production line to form mixed batches of product—without an additional mixing step.