# Elimination of the Solid Graininess Issue with Different Micro-Pattern Structures at Flexo Printing
## 1 Introduction  
A relief printing plate is used as a printing form in flexographic printing. The printing plate is mounted onto the printing cylinder using an adequate substructure with defined height and compressibility [1]. Flexo printing systems are widely used in applications such as plastics, paper, cardboard packaging, and packaging labels [2]. Due to the ability to print a wide variety of functional inks on different substrates, this highly efficient technology has also been successfully applied in various printed electronics applications, such as microscale conductive networks [3]. Figure 1 shows us the flexo printing system: the fountain roller transferring inks to the anilox roller; the anilox roller transferring inks to the printing plate; and the printing plate transferring inks to the substrate. Computer-to-plate (CTP) technology processes the image areas on the opaque layer on the plate surface and makes them ready for exposure. As micro-patterns begin to be created, a more evenly distributed ink layer begins to be created on the surface. The purpose of the micro-patterns created on the plate is to create various pits in the solid areas on the plate so that printing can be carried out with lower volume aniloxes with less ink consumption. It will provide a high level of performance by using smaller micro-patterns along with CTP and developing technology [4, 5]. There are many process parameters that can affect print quality in flexography [6], such as the surface structure of the plate surface [7], anilox cell volume and frequency [8], printing speed, applied pressure, and ink [9]. The correct amount of ink required to transfer to the printing plate is controlled by adjusting the engraved cell parameters. The capacity of ink on an an anilox roller is usually stated in cubic centimeters of ink per square meter; this is an estimate of the maximum theoretical ink transfer to the substrate [10]. Various techniques and methods have been developed for the evaluation and characterization of flexographic printing plates according to their performance. For the three types of plates (i.e., rubber, liquid photopolymer, and solid sheet photopolymer plates), the basic principles and methods used in the evaluations are similar. Important properties include volume, surface, and application properties (e.g., resistance to solvents and inks) [1]. Figure 2 shows us flexo printing plates in lateral view. Relief depth affects the printed line width and dot size as it plays a role in the deformation of the plate. For instance, deep relief depth makes it easier to be affected by external impacts. Lower relief depth makes a stronger plate. Relief depth should be balanced by plate thickness in order to correct relief depth and should follow the manufacturer's recommendations. In recent years, great advances in the development of photopolymer printing plates have increased the quality of flexography, making it a strong competitor for printing processes. However, there are many process parameters that can affect print quality in flexography printing. There is little research on the parametric study of flexography, and this provides the opportunity for further study [6]. Figure 1: Flexo printing system. Figure 2: Fotopolymer flexo printing plate. One of the most important elements affecting the print quality in flexo printing systems is the choice of plates [11]. The plate is prepared before the real printing starts, while the dot gain is observed via the test printing at the conditions desired to be produced [12]. The dot gain adjustments required for the preparation of the plate are made based on the results of this process, and the plates are prepared. The important thing here is that each printing variable remains fixed so that optimal plates are prepared. By managing how the printing variables affect the printing process, unnecessary waste of time is prevented, and the plates at the right properties are prepared in one sitting. Computer-to-plate imager technology is used to process plates.