Frequently Asked Questions

1. What do you mean by DIGITAL as it relates to page packs?

2. What do you mean by injector for ink delivery?

3. Is your injector system a gear driven pump system?

4. What are the advantages of injector inking over open fountain?

5. How do I request a site survey from CGI?

6. My press was manufactured by so-and-so. Can CGI retrofit these units?

7. My company is thinking about a new press, can CGI injectors be specified as original equipment?

8. Can I interface your injector system with my existing console?

9. Are your electronics remotely mounted?

10. Other injectors have only a ± 5 psi. tolerance for supply ink pressure; that is a tight tolerance through the speed range of the press, what is CGI’s tolerance?

What do you mean by DIGITAL as it relates to page packs?

The CGI page packs use three principal technologies which when combined; result in an extremely precise delivery of ink.

First, the page pack incorporates a simple piston and barrel combination that when rotated by the prime driver displaces (pumps) ink in a predictable manner. The piston/barrel arrangement combines to produce a fixed amount of ink for each revolution of the prime driver. The prime driver is a stepping motor. The construction of the page packs determine the amount of ink which will be delivered for each revolution of the piston. This accuracy of construction and the resulting tolerances create accuracies of +/- .05 of standard densities.

Second, the page pack utilizes a special class of motor called a stepping motor. The stepping motor consists of a wound stator (field windings) and a magnetized rotor. This motor is unique in that the rotor has 400 discreet positions as it moves through one revolution. The motor contains no commutaters nor does the motor require periodic maintenance.

The rotor may occupy only one of these 400 locations. In this way, a wave drive signal is capable of causing the motor to “move” a discreet number of “steps”. Knowing the number of steps the motor has moved allows one to know the exact location of the motor rotor. In this way the motor moves in a “digital” way, one step at a time. This motor is not referred to as an analog motor as one cannot impress a simple voltage to cause rotary motion similar to an AC or DC motor. The stepping motor is not a speed device but rather a precise position device.

Third, the stepping motor movement is governed by a CPU. The CPU simply generates a series of step commands to the wave generating circuits. The wave generating circuits cause the motor to advance one position at a time out of the 400 possible steps or positions.

The CPU keeps track of the number of steps the motor has been commanded to make and therefore “knows” the amount of ink delivered. The system works completely in the digital domain. At no time are the line shaft pulses converted to an analog value. The CPU, stepping motor and piston all move in a step like or digital manner. This can best be seen by the jittery motion of the pistons when at work.

To further this statement, if you were to place all of the cranks at the same phase angle and then apply a continuous line shaft signal to the system, you will observe that the cranks never fall out of phase with each other as they rotate. Only a digitally controlled system could produce this type of angular accuracy.

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What do you mean by injector for ink delivery?

CGI’s computer controlled ink injectors deliver on the promise to revolutionize your existing ink train.

What fuel injection did for the auto industry, ink injection is now doing for the printing industry. Open fountain ink trains have been the preferred method of ink delivery for many years. From time to time, systems are announced with great fanfare, which modify the way one adjusts the blade but ultimately none have made any real progress towards guaranteed density control. Computerized ink injection provides precise density control across the printed image, at all press speeds, by precisely controlling the volume of ink delivered to each control zone. The patented CGI design does not rely upon the deflection of a blade to regulate ink flow. CGI digital ink injectors meter the ink into your ink train on a key by key basis. No more open fountain ink to get contaminated with paper dust and grit. No more racing around your press room with buckets of ink or the expense of ink fountain levelers to replenish your open fountains. Most importantly, no more keys or cam levers to set and maintain. Our embedded microprocessors deliver only the amount of ink needed to achieve your density requirements on a key by key basis. As the press speed varies, the computers respond without density variation, image after image. Digital injecting means repeatability and long term stability giving your operators the tools they need to lower startup times, reduce waste and almost eliminate maintenance while at the same time delivering the quality your customer demands. The CGI injector inking system has been designed for open fountain conversions and may also be specified as original equipment.

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Is your injector system a gear driven pump system?

No. The page pack incorporates a simple piston and barrel combination that when rotated by the prime driver displaces (pumps) ink in a predictable manner. The piston/barrel arrangement combines to produce a fixed amount of ink for each revolution of the prime driver. The prime driver is a stepping motor. The construction of the page packs determine the amount of ink which will be delivered for each revolution of the piston. This accuracy of construction and the resulting tolerances create accuracies of +/- .05 of standard densities.

The page pack utilizes a special class of motor called a stepping motor. The stepping motor consists of a wound stator (field windings) and a magnetized rotor. This motor is unique in that the rotor has 400 discreet positions as it moves through one revolution. The motor contains no commutaters nor does the motor require periodic maintenance.

The rotor may occupy only one of these 400 locations. In this way, a wave drive signal is capable of causing the motor to “move” a discreet number of “steps”. Knowing the number of steps the motor has moved allows one to know the exact location of the motor rotor. In this way the motor moves in a “digital” way, one step at a time. This motor is not referred to as an analog motor as one cannot impress a simple voltage to cause rotary motion similar to an AC or DC motor. The stepping motor is not a speed device but rather a precise position device.

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What are the advantages of injector inking over open fountain?

The first readily apparent advantage of injector inking versus open fountain is that the CGI injector system uses an enclosed ink supply. The dirt, contamination and mess of open fountain are eliminated; the ink is enclosed and not open to the environment. More importantly, injectors provide direct control of the image through volumetric control, not indirect control of the film with blades.

Digital volume metering eliminates the need for accurately setting the fountain blade assembly and knurled pickup roller. The ink volume delivered by each of the injector keys is computer controlled and does not rely on gap settings for accuracy. Removing the gap setting dependence improves reliability, lowers maintenance costs and produces a more consistent image density.

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How do I request a site survey from CGI?

Just click on this link, site survey and fill out the short questionnaire; that is all there is to it.

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My press was manufactured by so-and-so. Can CGI retrofit these units?

Yes. CGI has been retro-fit on almost every press in use today. In addition, CGI digital ink page packs are available as OEM equipment on most major presses being produced today. View the CGI customer list to view the breadth of the CGI installations world-wide. Use the name and number available to call and inquire as to the success of the installation and the increase in quality and reduction in waste.

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My company is thinking about a new press, can CGI injectors be specified as original equipment?

Yes. Most of the major press manufacturers now offer CGI digital injector systems on their presses.

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Can I interface your injector system with my existing console?

Yes. While CGI offers consoles for page pack control as well as water and ink control, CGI has successfully integrated control with all of the present control and control manufacturers in the marketplace.

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Are your electronics remotely mounted?

No. All CGI double-wide systems utilize embedded micro-processors for both convenience and lack of complicated wiring.

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Other injectors have only a ± 5 psi. tolerance for supply ink pressure; that is a tight tolerance through the speed range of the press, what is CGI’s tolerance?

The CGI ink supply tolerance is from 25 to 45 psi. Any pressure within this range is suitable for the system and the assurance of precision.

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