Heidelberg CD102 Four-Color Offset Printing Machine Operating Guidelines

 

The Heidelberg CD102 four-color offset printing machine is known for its high-speed printing, precise color registration, and stable performance. However, it is a delicate piece of equipment that demands strict adherence to specific operating conditions. It requires a well-maintained printing environment, stable power supply, suitable temperature and humidity, proper ventilation, and precise operation. Any deviation from these requirements can lead to machine breakdowns, requiring expensive repairs by the manufacturer. Therefore, operating personnel must be highly responsible and strictly follow the operating procedures to ensure the Heidelberg offset printing machine's optimal performance.

1. Preparation for work should be thorough each day. Before starting the shift, assess the machine's operational status and maintenance history, check for any faults, and ensure the machine is in excellent technical condition.

2. When receiving a job order, carefully read the instructions and organize the printing tasks accordingly. Ensure that the job order is well-structured, including information on powder application, ink color sequence, and paper size. Accurately input the paper dimensions, thickness, and adjust the feeding, guiding, and sheet delivery devices. Prior to mounting the printing plate, inspect its appearance for quality, ensuring that it is flat, clean, and evenly coated with the necessary chemicals, free of damage, creases, scratches, dirt, or ink spots. Understand the layout specifications, graphics, and dot quality, and make the necessary adjustments in the ink and water settings based on the graphics and blank areas. Then, proceed with plate mounting.

3. Before registration, reset the plate cylinders to their default position, perform an initial ink key impression, and have an assistant check the alignment. The press operator should verify that the printing specifications meet the job requirements, make minor adjustments to ink and water balance, and achieve accurate registration. Once registration is correct, have a supervisor review and sign off on the job. After approval, arrange for cleaning and wash the rubber blanket, and then print a test sheet for further examination. After cleaning the rubber blanket, print waste sheets until the rubber blanket is clean, and proceed with official printing.

4. Control the ink-water balance during the printing process. Ink-water balance is a dynamic equilibrium that is constantly changing. If the ink supply to the plate exceeds the balance, ink will spread into non-image areas when subjected to high pressure, leading to dirty prints. Conversely, if the water supply to the plate exceeds the balance, an excess of water will be left on the image area when the water roller passes, causing the ink layer on the image area to emulsify and resulting in dull, non-glossy prints. Various factors, including machine speed, temperature and humidity variations in the printing environment, ink, paper type, and changes in the hydrophilicity of the plate's non-image areas due to increasing printing, can directly impact the ink-water balance.

To maintain the ink-water balance:

a. Keep the workshop temperature and humidity stable, as temperature fluctuations can affect ink viscosity and flow. It's best to maintain a temperature range of 18°C to 22°C and a relative humidity of 50% to 70%.

b. Maintain a consistent printing speed to ensure ink-water balance stability. Inconsistent machine speeds can lead to a loss of control over the ink-water balance.

c. Understand the characteristics of different materials, such as paper and ink. Different paper and ink types have varying requirements for ink-water balance. Factors like paper texture, moisture content, ink viscosity, flow properties, and pigment particle size should be considered.

d. Use a reasonable amount of drying oil. While adding drying oil to ink can accelerate drying, excessive use can make the ink sticky and disrupt the ink-water balance.

e. Accurately adjust the pressures of the plate, ink, and water rollers. These pressures play a crucial role in maintaining the ink-water balance. It's essential to maintain the water supply within a stable range while keeping the ink supply consistent. This ensures uniform ink coverage and stable printing quality.

5. After completing the day's printing tasks, document the job status and store the ink settings. Reset the plate cylinders to their default position, withdraw ink from the ink fountain, and apply an anti-skinning agent. When cleaning the press, select the units that require cleaning and set the washing speed. Prepare cleaning solution and two bottles of water. Pour a small amount of cleaning solution onto the ink roller while simultaneously adding a small amount of water. This method not only cleans the ink roller but also removes paper lint and dust, reducing water usage and cleaning time. This approach not only reduces production costs but also ensures the machine's maintenance, keeping it in excellent operating condition.