Nickel Oxide-based Flexible Thin-Film NTC Thermistors by using reverse offset printing

In recent years, the use of printing methods to fabricate electronic devices (printed electronics) has attracted attention because of their low cost and low environmental impact. Printing technology enables the high-throughput fabrication of electrical circuits on film substrates, providing inexpensive personal healthcare devices to monitor health status in real-time. Temperature detection is one of the central concerns as a fundamental physical quantity in various fields. In 2013, a highly sensitive flexible thermistor was reported by formulating aqueous inks of nickel oxide nanoparticles for inkjet printing. However, the calcinating of the nickel oxide (NiO) layer required a high-temperature process of more than 200°C, which required expensive polyimide films with high heat resistance. It is necessary to promote further the development of low-temperature processes for printed thermistors to realize flexible NTC thermistors at low cost using printed electronics technology. In screen printing and inkjet printing, the definition of the ink pattern applied on the substrate changes due to spreading and coffee distortion phenomena, and the thickness between sensors becomes non-uniform, which is a structural consistency problem that can lead to variations in sensing performance. This study developed a printing and low-temperature calcinating method of NTC thermistors with a temperature-sensitive layer of nickel oxide by using reverse offset printing. The NTC thermistors were fabricated by printing a comb-like pattern of silver nanoparticles and a thin nickel oxide film on a glass substrate. In addition, the low-temperature formation of a nickel oxide layer by oxygen plasma treatment was investigated, and XPS was used to carry out compositional analysis of the surface. Together with the plasma-assisted calcinating, a flexible NTC thermistor formed on polyethylene terephthalate (PEN) film is demonstrated.

Influence of Printing Technique and Printing Conditions on Prints Recycling Efficiency and Effluents Quality

The aim of this work was to determine the influence of the conventional offset printing technique and digital electrophotography printing with liquid toner (LEP) on some optical properties of recycled fibres. A series of LEP prints was made with the variation of the negative voltage of the developing drum (−200 V, −280 V, −350 V, and −430 V) after calibration of the machine and achieving standard densitometry values. Besides deinkability aspects, the quality of wastewater effluents after process of prints recycling was observed in order to make a conclusion regarding how different printing techniques, conditions in printing process, and different types of inks can affect the wastewater effluents. Results of image analysis showed that by increasing the negative voltage of developing drum in LEP printing technique, the formation of large ink particles on handsheet from recycled pulp increases. Depending on the size of the negative voltage of the developing drum, under the same experimental conditions, handsheets made from LEP recycled fibres have lower whiteness gain, brightness gain, and ΔERIC of handsheets compared to those made from the offset prints. In addition, a certain correlation was found between IEERIC (ink elimination), chemical oxygen demand (COD), and total organic carbon (TOC) of wastewater effluents after recycling of LEP prints and offset prints as well. Organic water pollution parameters (COD and TOC) showed higher values in wastewater after recycling of offset prints compared to recycling of LEP prints.

An investigation of the tensile characteristics of printed handsheets

Purpose The purpose of this paper is to investigate the influences of fibre lengths and a given range of paper grammages on the fundamental properties of unprinted and printed papers by using mineral oil-based offset printing inks and also evaluate these results in terms of printing and tensile characteristics. Design/methodology/approach A design research approach has been based on the production of various laboratory handmade papers and their printing process with mineral oil-based offset printing inks. The analysis of mechanical and structural tests results of the unprinted and the printed papers have been evaluated. Findings This study is confirmed that the mineral oil-based offset printing inks can be easily applied to the surface of papers having different grammages and pulp contents. An increase was observed in the tensile index values of the papers with the printing process, and these increases were more evident (about 80%) particularly in low grammage papers having high short fibre content. Originality/value The originality of this work is based on understanding and comparing the effects of grammage and the effect of pulp contents (having long and short fibre) on tensile characteristics of printed and unprinted handsheets.

Maintenance Preventive Scheduling of Critical Components in Offset Printing Machine (Case Study : PT. XYZ)

Maintenance activities are generally considered as supporting activities in the production process. However, this activity is very important because it contributes directly to the smooth running of the production process and productivity. PT. XYZ is a company engaged in mass media or newspapers since September 8, 2015. In the newspaper production process, PT. XYZ experienced delays in the production process due to damage to the component parts of the printing machine, in which the Offset printing machine is the core printing machine that is always used to print newspapers. Based on data on the frequency of damage during 2020 which was obtained from observations and interviews with operators, damage to machine components for 1 year on the offset printing machine counted 73 times that it was damaged. Thus making the machine stop operating from the effective working time of the machine, which is 264 days/year. This is due to the unavailability of a machine maintenance schedule because the company is still implementing a breakdown maintenance system. Thus the researcher aims to calculate the value of the identified critical components and calculate the effective time of machine operation for scheduling replacement of critical components of offset printing machines using the Reliability Centered Maintenance method. Based on the results of data processing using the Reliability Centered Maintenance method, the contactor component is determined as a critical component where the value of the Risk Priority Number is 72 with an average checking time of 11,250 minutes and component replacement time of 7 times/year. For this reason, it can be concluded that the contactor is a critical component with a damage value of 72 and the scheduling time for component replacement is 7 times in 1 year.

OPTIMIZING THE ROLE OF INKING UNIT IN OFFSET PRINTING MACHINE

In-depth observations have been made on the printing process using the Heidelberg Speedmaster CD 102 machine. In this process, the ink unit becomes the biggest concern because of its role in the quality of the printout. Observations are made directly in the field on routine procedures carried out and discuss events in the field to identify problems and determine actions. The results of the study indicate that there are several things that must be improved related to the routine maintenance schedule, the technical setup of the inking unit and identification of potential problems as a reference for improving standard operations in the field.Keywords—Inking unit, offset printing machine, speedmaster machine

Correlation between Workers’ Characteristics and Health Complaints Due to Exposure to Organic Solvents in the Sidoarjo Offset Printing

Introduction: Organic solvents are chemicals that are often used by the printing industry and contain Benzene, Toluene, and Xylene which are toxic to humans. Chemicals that contain organic solvents are ink, glue, and others. Workers who are regularly exposed to organic solvents can have health complaints. The purpose of this study was to determine the correlation between workers’ characteristics and health complaints due to exposure to organic solvents in the Sidoarjo offset printing. Methods: This research was an observational study with cross sectional design. Population in this research was 30 workers. The sampling technique used simple random sampling and from the calculation results were obtained 24 respondents. This study had an independent variable, which was workers’ characteristics consisting of age, smoking habits, and work tenure. The dependent variable was health complaints of printing workers. Data collection used questionnaires and interviews. The research data were analyzed using fisher’s exact test to show the correlation between workers’ characteristics and health complaints. Results: The result of the analysis test found that there was no correlation between age (p=0.386) and smoking habits (p=0.376) with health complaints of workers. Moreover, the analysis test showed that work tenure variable had a correlation with health complaints of workers (p=0.041). Conclusion: A factor related to health complaints of workers was work tenure.Keywords: health complaints, organic solvents, worker characteristics