First of all, this paper deals with the fiber bonding and sheet formation mechanism of paper because good understanding of these two mechanism is very important in discussing papermaking technology and paper quality.
Paper is made of wood fibers. Cellulose and other carbohydrates of wood fibers form fiber bondings mainly by hydrogen bonding between hydroxyl groups during sheet formation.
Excellent surface strength of paper (linting free paper) made by Twin-Wire paper machines such as Bel-Baie Former, etc can be explained by the following mechanism.
1. A Twin-Wire papermachine is usually equipped with a Deculator which separates the individual air bubbles from the fiber and water, which results in reducing bubble content by 50 to 90 percentage. Without a Deculators papers suffer from foam marks and cannot be sold in the market.
2. Slice jet is introduced between two wires as quickly as possible by reducing air involvement as well as eliminating spouting action (pumping action of table rolls or foils of Fourdrinier), which result in less air content of wet web than Fourdrinier.
3. Consequently, fiber bonding is less hindered by air during sheet formation and a larger specific surface area produces a paper with higher surface strength suitable for offset printing.
Another type of a Twin-Wire former such as Bel-Bond, etc which has a top wire unit on a Fourdrinier, has different sheet formation mechanism and does not produce paper with the same surface strength of a Twin-Wire former mentioned above. Therefore we have to continue to accumulate its operating experiences and results.
As the next topic, this paper presents the recent development and essential design concept of stock inlet, wire part, press part, dry part and others.
No-draw press does not destroy fiber bonding (the Campbell effect, hydrogen bonding and so on) of wet sheet and contributes to higher paper strength.
A new theory on the effect of an artificial stone roll is presented. Granite consiste of feldspar (hydrophilic), mica (hydrophobic), and silica (both hydrophobic and hydrophilic). An artificial stone roll of granite is used for both low and medium grade paper such as newsprint and fine paper production. In manufacturing an artificial stone roll for low and medium grade paper with high pitch content, feldspar (hydrophilic) content should be increased. On the other hand, higher portion of mica (hydrophobic) of stone roll is necessary to produce fine paper consisting largely of cellulose.

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Econics 700 system has enabled us to keep the best combustion by measuring of carbon monoxide, hydrocarbons, opacity of exhaled gas from boiler. In 1981 we introduced Econics for No. 3 boiler. In early time, it was difficult to control the amount of air from automatically measured CO value for the reason of misadjastment of automatic combustion control system. As the results of some experiments, Econics system is now in successful operation in our mill with secure performance of CO control having much effect on the stabilized operation and cost reduction.

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Kitakami Mill of Mitsubishi Paper Mills, Ltd. started production in 1965. The mill is situated in the rich woodland of Iwate Prefecture, and specializes in the manufacture of bleached hardwood kraft pulp (LBKP) from 100 % domestic woodchips. The mill's main product is high quality fully bleached hardwood kraft pulp for general market.
About one-third of the product is for captive use at Nakagawa and Takasago Mills, another one-third is sold to domestic paper manufacturers, with the remainder being exported.
To reduce energy cost, the mill has recently started a waste wood boiler to replace an oil-fired boiler. In fact, this has virtually eliminated oil consumption.

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紙パルプ産業における原料および製紙技術の変遷は大きく, 主なトピックスを拾うと以下のようになる。すなわち, パルプ材の海外依存の高率化, 針葉樹材から広葉樹材へ主体が移行, ユーカリ材の登場, 高収率メカニカルパルプの増加, 古紙利用の脱墨パルプ (DIP) の大量使用, ツインワイヤーマシンの採用, 新聞用紙の軽量化, 等々である。これらを背景として, 現在紙パルプ産業の抱えている課題は, エネルギー問題, 公害, 原料需給, 生産性向上と高品質化の 4 つといわれている。
これらの課題に対処するために, 抄紙工程のエンドポイント測定を行う B/ M 計センサに対してユーザーからは, 原料と抄紙状態の変動に影響されにくい水分センサを開発することを要求されてきた。
ここに紹介する N/T ビーム水分計は, 光源ヘッドから照射された近赤外線が紙を多重散乱して受光ヘッドに至るNビームと, 紙を直進透過して受光ヘッドに至るTビームの, 2つのビームを備えている。各ビームには 1.8μm の比較光と, 波長 1.94μn の測定光が交互に照射しており, N, T 両ビーム合わせて 4 つの紙に関する情報が得られる。これらの信号を, B 計から得られる坪量信号と合わせて計算機で演算して, 精度の高い水分率の値を得ている。

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Studies were carried out on the on the preparation of a new chemical pulp from woody and nonwoody cellulosic materials by hydrogen peroxide-alkali (PA) process.
The cooking liquor was a mixture of water, hydrogen peroxide (3% on raw materials), sodium hydroxide or sodium carbonate (as Na₂O 10-20% on raw materials) and small quantities of auxiliaries (EDTA, DTPA, etc.), the liquor ratio of the mixture to cellulosic materials being 4-10l/kg.
Hydrogen peroxide alkaline pulp (PAP) was easily obtained from raw materials after 0.5-3 hours at 120-180°C in a cooking liquor (giving total yield of 41.4-68.1% rejects 0.2-17.9% and screened 30.8-61.6%). Unbleached pulp gave 7-86 kappa no. By this process there was no need for recourse to disc refiner or other like processing machine.

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