74. What is offset printing dampening device?
A: In the offset printing, the fountain solution is supplied by the wetting device. The main function of the fountain solution is to supply the plate fountain solution. At the same time, it must play the technical role of the wetting device to meet the technical requirements of the offset printing.
75. Which components constitute the wetting device?
Answer: The wetting device includes three parts: a water supply device, a homogenizing device and a watering device. The constituent components of the wetting device include a water bucket roller, a water transfer roller, a string water roller and a water roller.
76. What is the technical role of the wetted device?
A: The technical role of the wetting device is to evenly coat the fountain solution on the surface of the printing plate without affecting the normal printing process performance. That is, in the process of applying or conveying the fountain solution, the normal printing performance of the ink, such as the emulsifying property, transfer property, flow property, acid resistance property of the ink, and the drying property of the ink, etc., cannot be influenced. At the same time, it cannot affect the normal printing performance of the printing plate surface, the ink absorption performance, mechanical properties, and the integrity of graphic parts in the graphic part, the physical properties and chemical properties of the blank part of the protective layer, and the wetting properties of the blank part. , mechanical properties, etc.
77. Offset printing and wetting device must meet the technical requirements of offset printing process?
A: Offset wetting devices must meet the following offset printing technology requirements:
1 to form a uniform layer of water on the surface of the plate;
2 can be stably supplied fountain solution;
3 no mechanical damage to the printing plate;
4 can adjust the amount of fountain solution supply;
5 can meet the needs of printing speed;
6 able to adapt to changes in printing speed requirements;
7 easy to operate, good adjustment performance.
78. What are the types of offset printing dampening devices?
Answer: 1 According to the contact form of the dampening device, the dampening device can be divided into direct contact (printing plate) form and non-direct contact (printing plate) form;
2 According to the form of dampening device output dampening solution, wetting device can be divided into continuous output form (Dagren moistening device) and discontinuous output form (commonly used dampening device).
79. What is a commonly used wetting device?
Answer: From the contact form of the wetting device, the commonly used wetting device is a direct contact (print plate), discontinuous output type wetting device, and is a commonly used wetting device for monochrome offset printing presses and two-color offset printing presses.
80. What is the Daglen moisturizing device?
A: The Daglen wetness device, a continuous moistening device developed in the 1960s in the 20th century. In the printing process, the fountain roller transmits the fountain solution to the transfer roller by rotating, and then the fountain roller coats the plate with the fountain solution through the inking roller, so it is also a non-direct contact (print plate). Wetting device. Used for four-color offset presses and web offset presses.
81. What are the performances of the components of commonly used wetting devices?
A: The fountain roller is an important component of the dampening device. It is usually made of copper alloy or chrome-plated copper alloy. It has strong corrosion resistance and hydrophilicity. It makes intermittent rotation in the printing work. Its rotation angle can adjust the amount of dampening fluid output.
Water transfer roller: Its role is to swing the fountain roller and the string water roller through the mechanical transmission, and send the fountain solution out. The swing or stop of the water transfer roller can be automatically controlled and manually controlled according to the needs of the printing process.
String water roller: its role is uniform water, while working in the rotation while there is an axial movement, and its rotation power from the plate cylinder, the purpose is to ensure that the water roller and plate surface line speed consistent.
Water roller: There are two, between the water roller and the plate cylinder, relying on the friction force of the plate and the water roller to rotate.
82. How to adjust the commonly used wetting device?
A: In the actual printing production, the adjustment of commonly used wetting devices has the following two aspects;
One is to adjust the pressure of the water roller and the string water roller and the printing plate. The sum of the pressures among the three is consistent, which directly affects the coating performance of the water roller. The adjustment standard is to make the surface speed of the printing plate, the surface of the water roller and the surface of the water roller equal.
The second is to adjust the axis of the water roller and the series of water rollers and the plate cylinder in parallel, otherwise the fountain solution could not be transmitted normally. Actual production, due to improper use, the adjustment of the two ends of the water roller, and the deformation of the water roller velvet sleeve, etc., can easily cause the water roller, string water roller and the plate cylinder axis is not parallel, so in the actual production Should always check and find problems in a timely manner.
83. What are the characteristics of commonly used wetting devices?
A: The advantages of commonly used wetting devices: simple structure, easy operation, and adapt to the process requirements of speed printing. Disadvantages: The use of non-continuous water supply, easy uneven fountain solution coating phenomenon; due to intermittent rotation of the fountain roller, it is easy to cause the impulse in the fountain fountain solution, resulting in instability of fountain solution output.
84. What are the working properties of the various components of the Dageren wetted device?
Answer: The working performance of the various components of the Daglen wetting device is basically the same as that of the commonly used wetting devices. The differences are:
1 Dagelun wetted device water roller, generally another motor drive, mainly to facilitate the adjustment of the amount of water and transfer roller and plate relative speed, water transfer roller is generally lower than the plate surface speed of about 30% That is, there is a certain amount of relative slippage between the water transfer roller and the printing plate, and in the actual production, the amount of water supply is adjusted by adjusting the relative sliding amount.
2 The ink roller is located between the ink roller and the printing plate, and the peripheral speed is generally equal to the line speed of the printing plate surface according to mutual pressure and friction.
3 Adjust the pressure and relative slippage of the transfer roller and ink roller. Excessive ink pressure will cause slippage between the ink roller and the printing plate, resulting in deformation of the dirty plate and dot. Between the water transfer roller and the ink roller under the appropriate pressure, adjust the relative sliding amount between the roller and the ink roller. Because the water film adheres to the surface of the water transfer roller, the friction force generated when the roller contacts the ink roller can be properly adjusted. Guaranteed normal printing.
85. What are the characteristics of Dageren wetness device?
A: The Daglen wetting device is a continuous wetting device with more advantages for high-speed printing. However, when the wetting device regulates the water transfer roller, it easily causes the ink roller to vibrate, and the printed product is prone to ink bars.
86. What are the rules for regulating dampening devices?
Answer: Regardless of the type of wetting device, its regulation should follow the following rules:
1 Adjust the relationship between the circumferential speed of the string water roller (or water transfer roller) and the plate surface line speed;
2 Adjust the relationship between the water roller (or water transfer roller) and the surface pressure of the printing plate;
3 Adjust the relationship between the water roller and the plate cylinder axis. The parallel relationship between the water roller and the plate cylinder, including the plane parallel relationship and the spatial parallel relationship;
4 Adjust the working status of the fountain solution.
87. What is the relationship between the peripheral speed of the water roller (or ink roller) and the surface speed of the printing plate?
Answer: For the commonly used wetting device, the circumferential speed of the string of water rollers should be equal to the line speed of the surface of the printing plate, so that the water roller can make a pure rolling on the surface of the printing plate, so that no damage can be caused to the graphic portion of the printing plate. The blank part of the plate forms a uniform water film. For Dachrun non-direct contact (printing plate) wetting devices, the circumferential speed of the screed roller should be equal to the line speed of the plate surface, so that the inking roller can make pure rolling on the surface of the plate. Graphic parts will not cause damage, and will not cause ink or dirty plates on the blank part of the printing plate.
88. How to adjust the surface pressure of the water roller and printing plate?
A: Adjust the pressure order: first adjust the pressure of the water roller and the water roller, and then adjust the pressure of the water roller and the plate.
Adjustment method: adjust the pressure of the water roller and the string water roller by adjusting the eccentric sleeve of the eccentric mechanism at both ends of the water roller, adjust the pressure of the water roller and the string water roller by adjusting the hand wheel on the connecting rod, and adjust the connecting rod The upper handwheel regulates the pressure of the water roller and the plate surface.
Check the results of the adjustments: How much pressure is appropriate between them and there is no uniform standard. There are three ways to check if the water roller is doing pure rolling:
One is to correct the pressure of the water roll and the string water roll;
Secondly, the relative speed of the water roller against the water roller suede fiber is checked. The opposite direction of the suede fiber and the water roller is opposite. The relative speed of the water roller is small, and the direction of the suede fiber is the same as that of the water roller.
The third is to check the status of the dots of the printed products. If the dots are deformed due to this reason, the dots will increase along the direction of the mouth or the direction of the tip. (Drilling) ("Printing Technology")
A: In the offset printing, the fountain solution is supplied by the wetting device. The main function of the fountain solution is to supply the plate fountain solution. At the same time, it must play the technical role of the wetting device to meet the technical requirements of the offset printing.
75. Which components constitute the wetting device?
Answer: The wetting device includes three parts: a water supply device, a homogenizing device and a watering device. The constituent components of the wetting device include a water bucket roller, a water transfer roller, a string water roller and a water roller.
76. What is the technical role of the wetted device?
A: The technical role of the wetting device is to evenly coat the fountain solution on the surface of the printing plate without affecting the normal printing process performance. That is, in the process of applying or conveying the fountain solution, the normal printing performance of the ink, such as the emulsifying property, transfer property, flow property, acid resistance property of the ink, and the drying property of the ink, etc., cannot be influenced. At the same time, it cannot affect the normal printing performance of the printing plate surface, the ink absorption performance, mechanical properties, and the integrity of graphic parts in the graphic part, the physical properties and chemical properties of the blank part of the protective layer, and the wetting properties of the blank part. , mechanical properties, etc.
77. Offset printing and wetting device must meet the technical requirements of offset printing process?
A: Offset wetting devices must meet the following offset printing technology requirements:
1 to form a uniform layer of water on the surface of the plate;
2 can be stably supplied fountain solution;
3 no mechanical damage to the printing plate;
4 can adjust the amount of fountain solution supply;
5 can meet the needs of printing speed;
6 able to adapt to changes in printing speed requirements;
7 easy to operate, good adjustment performance.
78. What are the types of offset printing dampening devices?
Answer: 1 According to the contact form of the dampening device, the dampening device can be divided into direct contact (printing plate) form and non-direct contact (printing plate) form;
2 According to the form of dampening device output dampening solution, wetting device can be divided into continuous output form (Dagren moistening device) and discontinuous output form (commonly used dampening device).
79. What is a commonly used wetting device?
Answer: From the contact form of the wetting device, the commonly used wetting device is a direct contact (print plate), discontinuous output type wetting device, and is a commonly used wetting device for monochrome offset printing presses and two-color offset printing presses.
80. What is the Daglen moisturizing device?
A: The Daglen wetness device, a continuous moistening device developed in the 1960s in the 20th century. In the printing process, the fountain roller transmits the fountain solution to the transfer roller by rotating, and then the fountain roller coats the plate with the fountain solution through the inking roller, so it is also a non-direct contact (print plate). Wetting device. Used for four-color offset presses and web offset presses.
81. What are the performances of the components of commonly used wetting devices?
A: The fountain roller is an important component of the dampening device. It is usually made of copper alloy or chrome-plated copper alloy. It has strong corrosion resistance and hydrophilicity. It makes intermittent rotation in the printing work. Its rotation angle can adjust the amount of dampening fluid output.
Water transfer roller: Its role is to swing the fountain roller and the string water roller through the mechanical transmission, and send the fountain solution out. The swing or stop of the water transfer roller can be automatically controlled and manually controlled according to the needs of the printing process.
String water roller: its role is uniform water, while working in the rotation while there is an axial movement, and its rotation power from the plate cylinder, the purpose is to ensure that the water roller and plate surface line speed consistent.
Water roller: There are two, between the water roller and the plate cylinder, relying on the friction force of the plate and the water roller to rotate.
82. How to adjust the commonly used wetting device?
A: In the actual printing production, the adjustment of commonly used wetting devices has the following two aspects;
One is to adjust the pressure of the water roller and the string water roller and the printing plate. The sum of the pressures among the three is consistent, which directly affects the coating performance of the water roller. The adjustment standard is to make the surface speed of the printing plate, the surface of the water roller and the surface of the water roller equal.
The second is to adjust the axis of the water roller and the series of water rollers and the plate cylinder in parallel, otherwise the fountain solution could not be transmitted normally. Actual production, due to improper use, the adjustment of the two ends of the water roller, and the deformation of the water roller velvet sleeve, etc., can easily cause the water roller, string water roller and the plate cylinder axis is not parallel, so in the actual production Should always check and find problems in a timely manner.
83. What are the characteristics of commonly used wetting devices?
A: The advantages of commonly used wetting devices: simple structure, easy operation, and adapt to the process requirements of speed printing. Disadvantages: The use of non-continuous water supply, easy uneven fountain solution coating phenomenon; due to intermittent rotation of the fountain roller, it is easy to cause the impulse in the fountain fountain solution, resulting in instability of fountain solution output.
84. What are the working properties of the various components of the Dageren wetted device?
Answer: The working performance of the various components of the Daglen wetting device is basically the same as that of the commonly used wetting devices. The differences are:
1 Dagelun wetted device water roller, generally another motor drive, mainly to facilitate the adjustment of the amount of water and transfer roller and plate relative speed, water transfer roller is generally lower than the plate surface speed of about 30% That is, there is a certain amount of relative slippage between the water transfer roller and the printing plate, and in the actual production, the amount of water supply is adjusted by adjusting the relative sliding amount.
2 The ink roller is located between the ink roller and the printing plate, and the peripheral speed is generally equal to the line speed of the printing plate surface according to mutual pressure and friction.
3 Adjust the pressure and relative slippage of the transfer roller and ink roller. Excessive ink pressure will cause slippage between the ink roller and the printing plate, resulting in deformation of the dirty plate and dot. Between the water transfer roller and the ink roller under the appropriate pressure, adjust the relative sliding amount between the roller and the ink roller. Because the water film adheres to the surface of the water transfer roller, the friction force generated when the roller contacts the ink roller can be properly adjusted. Guaranteed normal printing.
85. What are the characteristics of Dageren wetness device?
A: The Daglen wetting device is a continuous wetting device with more advantages for high-speed printing. However, when the wetting device regulates the water transfer roller, it easily causes the ink roller to vibrate, and the printed product is prone to ink bars.
86. What are the rules for regulating dampening devices?
Answer: Regardless of the type of wetting device, its regulation should follow the following rules:
1 Adjust the relationship between the circumferential speed of the string water roller (or water transfer roller) and the plate surface line speed;
2 Adjust the relationship between the water roller (or water transfer roller) and the surface pressure of the printing plate;
3 Adjust the relationship between the water roller and the plate cylinder axis. The parallel relationship between the water roller and the plate cylinder, including the plane parallel relationship and the spatial parallel relationship;
4 Adjust the working status of the fountain solution.
87. What is the relationship between the peripheral speed of the water roller (or ink roller) and the surface speed of the printing plate?
Answer: For the commonly used wetting device, the circumferential speed of the string of water rollers should be equal to the line speed of the surface of the printing plate, so that the water roller can make a pure rolling on the surface of the printing plate, so that no damage can be caused to the graphic portion of the printing plate. The blank part of the plate forms a uniform water film. For Dachrun non-direct contact (printing plate) wetting devices, the circumferential speed of the screed roller should be equal to the line speed of the plate surface, so that the inking roller can make pure rolling on the surface of the plate. Graphic parts will not cause damage, and will not cause ink or dirty plates on the blank part of the printing plate.
88. How to adjust the surface pressure of the water roller and printing plate?
A: Adjust the pressure order: first adjust the pressure of the water roller and the water roller, and then adjust the pressure of the water roller and the plate.
Adjustment method: adjust the pressure of the water roller and the string water roller by adjusting the eccentric sleeve of the eccentric mechanism at both ends of the water roller, adjust the pressure of the water roller and the string water roller by adjusting the hand wheel on the connecting rod, and adjust the connecting rod The upper handwheel regulates the pressure of the water roller and the plate surface.
Check the results of the adjustments: How much pressure is appropriate between them and there is no uniform standard. There are three ways to check if the water roller is doing pure rolling:
One is to correct the pressure of the water roll and the string water roll;
Secondly, the relative speed of the water roller against the water roller suede fiber is checked. The opposite direction of the suede fiber and the water roller is opposite. The relative speed of the water roller is small, and the direction of the suede fiber is the same as that of the water roller.
The third is to check the status of the dots of the printed products. If the dots are deformed due to this reason, the dots will increase along the direction of the mouth or the direction of the tip. (Drilling) ("Printing Technology")
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