Browse Prior Art Database

Ramp and Shift Motion Printer Control

IP.com Disclosure Number: IPCOM000060375D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Cavill, BR: AUTHOR [+2]

Abstract

A technique is described whereby a ramp and shift mechanism is applied to a print head motor drive system for a wire matrix printer to insure complete rotational tilting motion of the print head when driving against a variable mechanical load. Print head motor drive systems which drive print heads at a controlled velocity may also be required to exert forces against the side frame so as to establish left margin print starting positions and to shift the print head via a mechanical mechanism into one of two print positions. Pressing on the sideframe so as to rotate or tilt the head into a selected print mode requires large forces to be applied to the shift mechanism. It is important to prevent the forces from being transferred to the sideframe in the form of high velocities once the lever mechanism is shifted.

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Ramp and Shift Motion Printer Control

A technique is described whereby a ramp and shift mechanism is applied to a print head motor drive system for a wire matrix printer to insure complete rotational tilting motion of the print head when driving against a variable mechanical load. Print head motor drive systems which drive print heads at a controlled velocity may also be required to exert forces against the side frame so as to establish left margin print starting positions and to shift the print head via a mechanical mechanism into one of two print positions. Pressing on the sideframe so as to rotate or tilt the head into a selected print mode requires large forces to be applied to the shift mechanism. It is important to prevent the forces from being transferred to the sideframe in the form of high velocities once the lever mechanism is shifted. In essence, the drive system must exert large forces for the shifting operation, but the forces must be removed quickly. Therefore, a shift control algorithm was developed to provide the proper force and control the velocities to insure operational requirements of the print head. The shift mechanism consists of lever 10, as shown in Fig. 1, and spring 11 which is attached to the bottom of the head carriage 12. Print head 13 is tilted by pressing bar 14 at point "A" so as to tilt print head 13 so as to be able to print in one configuration. Pressing bar 14 at point "B" will cause lever 10 to tilt print head 13 in the opposite direction for the other print configuration mode. The force applied to spring 11 when point "A" or "B" is pressed is not linear. The shift mechanism rides along with the print head and to shift the head in one orientation. The head carrier containing the shift mechanism is driven into the left sideframe so that point "A" may be pressed. Driving the head carrier into the right sideframe, with contact at point "B", shifts the head in the opposite direction. When a command is received that a shift mode change is required, the head carriage is moved to the desired sidebar so as to shift the print head through the use of bar 14. Emitters attached to the head motor are used to indicate the position of the head relative to the sideframe and to indicate head carrier velocity. When motion stops, no emitter sequence variations will be observed; therefore, the control program assumes that the head is at zero velocity. When the head reaches zero velocity for the first time, while driving to the side frame, the control program assumes that the head has reached the shifter bar. Additional voltage must be applied...