In accordance with the requirements of the national standard of the Russian Federation GOST R 57641-2017 “Xerographic paper for office equipment. General specifications”, office paper, depending on its application and set of quality indicators, must be produced in one of three grades:
• A-grade paper is suited for single-sided and double-sided printing at any speed of copying and printing machines.
• B-grade paper is suited for single-sided and double-sided printing at speeds up to 100 copies per minute.
• C-grade paper is suited for single-sided and double-sided printing at speeds up to 50 copies per minute.
You can find technical specifications for each grade of paper in GOST R 57641-2017, in section No. 3 “Technical requirements” (Table 1).
In international practices, there is no unified classification and unified standard for office papers. There are no absolutely clear criteria for dividing into grades/classes of office paper; each manufacturer establishes its own classification (A, A++, B, C+ etc) in its regulatory documents.
Some of the key characteristics of office paper are: thickness, opacity, moisture content and whiteness.
Paper thickness is defined as the perpendicular distance between two opposing surfaces. Thickness is one of the important characteristics of paper that affects such characteristics as bending stiffness, which in turn has a certain impact on the passage of paper in the copier. Paper with low thickness usually has insufficient bending stiffness, and there is a risk of curling and jamming when paper passes through office equipment. Papers with a high thickness value are more rigid. Their relative inflexibility increases the likelihood of jamming because paper cannot bend properly when going around the rollers, drums, photoreceptor, rollers, and bending areas. A sufficient level of thickness for standard 80 gsm office papers is at least 100 microns.
Humidity is the amount of water in paper. Moisture content is an important factor as humidity affects the processing, printing and copying processes. In the electrographic (xerographic) printing method, paper is heated during toner fixation, so if the humidity exceeds 5.3%, paper will tend to curl, get wavy, and it will be impossible to make double-sided printing, and the quality of the print will be noticeably reduced. Humidity directly affects the electrical conductivity of paper. In addition, moisture content also affects the dimensional stability of paper. 4.0–5.2% is the optimal humidity range for office papers.
Opacity. With double-sided printing, it is very important that paper is opaque. The opacity of paper should be at least 90% to ensure that paper has the desired property of transmitting as little light as possible so that the text or other visual elements on paper would not be not visible or show through on the other side of the sheet.
Whiteness can be described as the ability of paper to reflect all colors of the spectrum equally. This means that paper diffusely reflects light at all wavelengths throughout the visible spectrum. Truly white sheet of paper has a high degree of reflectivity and will not absorb one wavelength more than another. The whiteness value, determined in accordance with the requirements of the International Commission on Illumination (CIE), corresponds to the visual perception of white paper, with or without fluorescent brightening agents, observed under a daylight source (for example, C/2° or D65/10°). All optical performance measurements are highly dependent on the light source and observer. The light source is standardized to a specific temperature value (“light temperature”), defined in degrees Kelvin (K). Since natural daylight has a variable spectrum depending on time of day, location, weather and other influencing factors, standard daylight sources have been created to ensure that standard and reproducible conditions are met.
The production of high-quality papers in Russia has traditionally been associated with JSC SLPK, and quality improvement has always been a priority for the company’s development.
Cartblank paper is produced on the most modern equipment, high-quality raw materials and necessary components. Strict quality control of the entire technological chain, a high level of technical specialists’ competence, constant development of technology and quality improvement, with environmental aspects taken into account, give our company the opportunity to produce paper for office equipment that meets international quality standards.
Cartblank paper is solely produced of virgin pulp fibres which ensures high light fastness and long-term protection against fading.
Cartblank paper is absolutely universal; it is designed for printing on laser, inkjet printers, copiers, and MFPs.
Cartblank office paper is produced with surface sizing (polymer coating).
Binders are used to increase the bonding forces between fibers and increase the strength of paper.
By bonding the fibers together, these substances increase the internal strength of paper and eliminate dusting and plucking of individual fibers.
Surface sizing improves the physical, mechanical, adsorption and printing properties of paper.
In addition, the maximum service life of your office equipment is guaranteed by the use of high-quality raw materials in the production of Cartblank paper, as well as the control over the content of resins and other inclusions.
Bleaching of softwood and hardwood pulp at our mill is carried out using ECF (Elemental Chlorine Free) technology. The process of pulp bleaching is accomplished through the use of chlorine dioxide and the oxygen-alkali bleaching stage.
The introduction of ECF technology for pulp bleaching is primarily aimed at improving the environmental aspects of paper production:
— Reduction of highly toxic compounds (chlorine dioxide) in wastewater.
— Significant reduction in fresh water consumption.
— Increasing the overall industrial safety of the enterprise and nearby communities.
— Production of cardboard and paper products based on strict international environmental standards existing in the global practice of the pulp and paper industry.
In sheet production, paper is packaged in reams of 500 sheets. Allowed deviation of the number of sheets according to GOST R 57641-2017 (section 3.3 Packaging/clause 3.3.4) should not exceed ±2% of the standard.
The actual target for production of paper reams on the cut-size lines of JSC SLPK is set for 500 sheets/ ream. In some reams the number of sheets is 498 due to the fact that paper is cut from 6 mother rolls on two production lines. Consequently, the number of sheets in a ream will be a multiple of 6. If you check more reams, you will find that the number of sheets in other reams equals 504. Thus, the number of sheets in reams of office paper may be 498, 500 or 504.
