A sheet manufacturing apparatus can easily adjust the stiffness of sheets made by the sheet manufacturing apparatus. The sheet manufacturing apparatus has a first material supply device that supplies a first material containing fiber; a second material supply device that supplies a second material containing fiber with an average fiber length shorter than the average fiber length of the first material; and a controller configured to control operation of the first material supply device and second material supply device. The controller has a first mode in which the first material is supplied from the first material supply device, and a second mode in which the second material is supplied from the second material supply device, and selects either the first mode or the second mode.

A method for controlling a fiber fractionation system for fractionating an input material into a long fraction (LF) stream comprising LF fibers and a short fraction (SF) stream comprising SF fibers includes measuring an average LF fiber length at one or more locations post-fractionation, and maintaining the average LF fiber length within a target variability range by automatically altering a rotational speed of a rotor of the fiber fractionation system.

A system for treating cellulosic fibers to improve paper, board and tissue quality; the system involves splitting fibers into an original portion having original fibers and a refinable portion. The refinable portion may further be fractionated by one or more fibers properties by a fiber fractionation system into a first fraction and a second fraction. The refinable portion as a whole, or a fractionated fraction thereof, is then refined to produce refined fibers. Varying amounts of the original unrefined fibers, refined fibers and possibly additionally fractionated unrefined fibers are blended together to form an optimized slurry that is processed by a paper machine into an optimized paper product. A master control system, fiber measurement system and optional fractionation maintenance system may be integrated with the overall system to regulate all processing.

Provided is a sheet processing device able to suppress consumption of sheets. The sheet processing device has a supply device that supplies sheets; an image acquisition device that acquires an image of a sheet supplied from the supply device; a first decision device that determines whether or not the sheet can be reused based on the image of the sheet acquired by the image acquisition device; and an inverter configured to discharge the sheet without reversing the first side and second side of the sheet when the first decision device determines that the first side of the sheet can be reused, and reverses the first side and second side of the sheet and then discharges the sheet when the first decision device determines that the second side of the sheet can be reused.

A method for treating cellulosic fibers to improve paper, board and tissue quality; the method involves splitting fibers from feed pulp into an original portion containing original fibers and a refineable portion containing original fibers. The refinable portion is refined to create a refined portion containing refined fibers. Varying amounts of the original unrefined fibers and refined fibers are blended together to form a recombined slurry that is processed by a paper machine into an optimized paper product. A master control system and fiber measurement system are integrated with the overall system to regulate all processing.

A system for treating cellulosic fibers to improve paper, board and tissue quality; the system involves splitting fibers into an original portion having original fibers and a refinable portion. The refinable portion may further be fractionated by one or more fibers properties by a fiber fractionation system into a first fraction and a second fraction. The refinable portion as a whole, or a fractionated fraction thereof, is then refined to produce refined fibers. Varying amounts of the original unrefined fibers, refined fibers and possibly additionally fractionated unrefined fibers are blended together to form an optimized slurry that is processed by a paper machine into an optimized paper product. A master control system, fiber measurement system and optional fractionation maintenance system are integrated with the overall system to regulate all processing.

A fiber body manufacturing method includes: a dispersing step of dispersing a mixture containing a defibrated material which includes fibers and a binding agent which exhibits a binding property by moisture absorption, the mixture having a moisture content of 10 to 30 percent by weight; a depositing step of depositing the mixture dispersed in the dispersing step; a humidifying step of imparting moisture by water vapor or mist to the binding agent in a deposit deposited in the depositing step so as to exhibit the binding property; and a forming step of forming the deposit humidified in the humidifying step into a fiber body.

A method for controlling a slice flow of a slurry having two or more component slurries through a headbox for a paper making machine includes, inputting a wire speed of the paper making machine; determining a jet velocity setpoint based on the wire speed; determining a header pressure setpoint for two or more headers to generate the jet velocity determined by the jet velocity setpoint, each header providing one of the two or more component slurries to the headbox; and controlling the slice flow by: generating a first speed command to a first slurry pump to generate a header pressure determined by the header pressure setpoint in a first header; and generating a second speed command to a second slurry pump to generate the header pressure determined by the header pressure setpoint in a second header.

Estimating or predicting runnability or end product quality risk level for a pulp or papermaking process is disclosed. The method includes measuring hydrophobicity values of samples originating from a same aqueous process stream. A hydrophobicity measurement signal is produced of measured hydrophobicity values as a function of time. A risk level is calculated for the process. At least one mathematical index is calculated based on the hydrophobicity measurement signal, and optionally based on the amount of particles in the sample, other property of the aqueous stream and/or production data. The mathematical index and optionally the amount of the particles, other property, and/or production data is used as a risk indicator input in the calculation. Based on the risk level calculated for the pulp or papermaking process, the runnability and/or end product quality risk level for the pulp or papermaking process is indicated.

A recycled sheet in which fibers are bonded via an additive agent includes a history including information that is related to characteristics.