Martin Krucinski

Intersheet spacing control and controllability of a copier paper path

This paper presents a control and controllability approach for a copier paper path. The paper path transports sheets from the feeder to the image transfer section. At arrival time, every sheet must synchronize with the photoreceptor. The hybrid character of the system makes classical control approaches difficult. A control scheme that controls intersheet spacings is proposed. A controllability analysis illustrates the influence of system geometry and actuators on system controllability for simplified system dynamics. Combined with a disturbance model, this can lead to an optimal paper path design strategy. An experimental setup was built for disturbance identification and control scheme evaluation.

A mechatronic approach to full sheet control using steer-able Nips

Abstract State of the art high speed color printers require sheets be accurately positioned as they arrive at the image transfer station. To accomplish this goal, a steerable nips mechanism has been designed and built. This mechanism is located upstream from the image transfer station. This steerable nips mechanism allows sheets to be precisely controlled in the longitudinal, lateral, and skew directions. In this paper we present the design, sensing strategy, and a control law based on state feedback linearization. Simulation and experimental results show that the proposed controller is able to correct for paper position errors in the above mentioned directions under the condition that the sheet has nonzero initial and final velocities. The system model is nonlinear and subject to four nonholonomic constraints.

A hybrid control scheme for a copier paperpath

Presents a hybrid control approach for a copier paperpath. The paperpath transports sheets from the feeder to the image transfer section. At arrival time, every sheet must synchronize with its image on the photoreceptor belt. A non-cooperative hybrid control scheme that controls intersheet spacings is proposed. The controller switches between different modes to satisfy all the system constraints. Cooperation, which enhances performance, is then introduced for a simplified system model, based on the notion of controllable regions. Simulations illustrate both strategies.

Printer media path closed loop control

The invention of parallel cut-sheet printing system architectures could potentially revolutionize the approach to building reliable, high-speed printers. Instead of speeding up an existing printer or designing a new, higher speed printer, a printing system is built utilizing multiple print engines printing in parallel, increasing speed and reliability.

Control of two contact point sheet registration devices for xerographic printers

Xerographic printers printing on pre-cut sheets need to register (align) each sheet with its corresponding image before image transfer. There exists a variety of sheet registration devices that perform this function, utilizing different actuator and sensor configurations. A majority of these devices have three or more degrees of freedom and contact the sheet at two points during registration. A control algorithm for this class of devices has been developed. The main contribution of the proposed control approach is that it avoids explicitly dealing with the non-holonomic constraints of the combined sheet and registration device system. This simplifies the control design compared to other approaches. The proposed control algorithm comprises of two parts: a generic part for two contact point devices and a registration device specific part which depends on the actuator configuration and kinematics of the registration device. It can also incorporate active control of the buckle that may form in the sheet portion between the two contact points during registration, hereby minimizing the possibility of sheet damage and jams.

Control of non-linear and non-holonomic sheet registration devices

In Xerographic printers, one important quality metric to customers is the image to paper registration. This metric measures how well the image is positioned on the paper on the finished print, relative to its intended position. In the media path the sheet registration device, located immediately upstream from the image transfer section, is responsible for aligning the sheet with the image. In modern, high-speed printers these devices are most often mechatronic devices utilizing sophisticated sensors and active feedback control. This paper gives an overview of registration goals and constraints, several existing technologies, and control approaches. The differential drive registration nip and current state of the art control approach are explained in detail.