Understanding the HP Indigo 5000 CLEMSON UNIVERSITY - GRAPHIC COMMUNICATIONS 4400
Why Choose the HP Indigo 5000?
The HP Indigo provides:
- high print quality
- a wide color gamut
- substrate versatility
- speed
- productivity
- flexibility
- variable data printing capabilities
The HP Indigo 5000 lends to high utilization and extra automation with:
- three paper trays to reduce paper switching and also accommodate different substrates
- high-capacity paper stacker
- stack capacity of 23.6" (or 6,000 sheets of 80lb. text)
- high speeds: 4,000 4-color 8.5" x 11" images per our (two-up)
How Does It Work?
- Electrophotography process (a printing and photocopying technique that works on the basis of electrostatic charges) that uses ElectroInk with a thermal offset blanket
- The liquid ink is key to achieving high image quality at high speeds
- The hot transfer blanket allows for high quality with substrate independence and minimal impact on the substrate
About HP ElectroInk
ElectroInk contains electrically charged ink particles, dispersed in liquid, which enable digital printing based on the application of controlled electrical fields that move the charged particles.
The ink uses very small particle sizes allowing for high resolution, gloss, sharp image edges, and very thin image layers.
- HP ElectroInk is offered in several colors:
- Standard process colors (CMYK)
- HP IndiChrome wide-gamut 6 and 7 color set (orange, violet and green inks)
- Light cyan and light magenta for photo prints
- White ink for transparent or colored substrates
- Specialty inks such as security ink
HP ElectroInk is a concentrated paste that is loaded into the press in cartridges. Once inside the press, the ink is fed into the ink supply tanks, diluted with oil, and combined with a charging control fluid for form a liquid mixture
About the Thermal Offset Process
The term offset refers to the printing technique where the inked image is transferred (or “offset”) from the plate cylinder to the rubber blanket and then to paper. The HP Indigo’s thermal offset process uses a heated blanket, which allows the ElectroInk, which possess pigment-carrying particles, to melt and blend into a film. Since the film is contacted a cooler surface, the HP ElectroInk adheres to the substrate and immediately solidifies.
Inside the HP Indigo
1. PRINTING IMAGING PLATE (PIP) CHARGES
- A uniform static charge is deposited on the photoconductor (the PIP) which is on the imaging cylinder.
- Via the scorotron, charged particles (atoms, molecules, and free electrons) are produced by a glow discharge effect (ionization of the air) through a high voltage.
- The positively charged particles are attracted to the charging device and neutralized, while the negatively charged particles move towards the PIP.
2. PIP EXPOSURE
- When exposed to light, the photoconductor becomes electrically conductive.
- As the PIP rotates, it passes the imaging units where the laser beams expose the image, which dissipates the charge in the image area.
3. IMAGE DEVELOPMENT
- The Binary Ink Developer (BID) units prepare a thin dense film of electrically charged ink (ElectroInk).
- The BID roller engages with the PIP drum and the electrical fields cause the ink paste to attract to the image area and repel the non-image areas.
4. PRE-TRANSFER ERASE
- LEDs illuminate the PIP and this allows for a homogenous conductivity across the PIP which disperses the charges.
- There is a clean and sharp image transfer onto the substrate.
5. FIRST TRANSFER
- The PIP rotates and contacts the electrically charged blanket on the transfer cylinder.
- The ink layer is transferred to the blanket.
6. INK HEATS TO FORM A FILM
- HP ElectroInk is heated and the particles partially melt and blend together.
- At the same time, the carrier oil is evaporated, collected, and reused as part of the the fresh ink in the tanks.
7. SECOND TRANSFER
- As ink contacts the substrate, which is below the melting temperature of the particles, the ink film solidifies, sticks to it and peels off the blanket.
8. CLEANING STATION
- After transferring the image, the cleaning station removes any residual ink and cools the PIP from heat transferred from the blanket.
- At this point, the PIP has made a complete rotation and is ready to be recharged for the next image.
An Overview
References
HP Indigo press 5000 [Brochure]. (n.d.). Retrieved from http://www.rti-rips.com/LinkedDocuments/EquipmentBrochures/HP_Indigo_5000_Press.pdf Tagansky, B. (2012, January).
HP-Indigo Technology and its Application to Photo Printing. In International Symposium on Technologies for Digital Photo Fulfillment (Vol. 2012, No. 1, pp. 31-34). Society for Imaging Science and Technology.
A special thanks to Hewlett-Packard for their demonstrations on the show floor. Photos and videos are from the annual DSCOOP Conference in San Antonio, Texas.