Conveyance device, printing device, and conveyance method

Abstract

A conveyance device including an upstream roller that supplies a sheet medium to be processed to a conveyance path; a downstream roller that conveys the supplied medium to a processing position; and a control unit that controls driving the upstream roller and the downstream roller to convey the sheet medium at a constant speed. The control unit determines the starting time of the upstream roller and the downstream roller when starting the conveyance operation based on specific information about the upstream roller and the downstream roller in a previous conveyance operation.

Description

BACKGROUND[0001]1. Technical Field[0002]The present invention relates to devices that use two sets of rollers to convey sheet media to a processing position, and relates more particularly to a conveyance device, printing device, and conveyance method that can eliminate the effect of back tension on the downstream rollers without increasing device size.[0003]2. Related Art[0004]A means of conveying paper or other types of sheet media is required in order to process such media in a printer or other device. Such conveyance devices generally have upstream rollers that supply the media from the part storing the sheet medium to the conveyance path, and downstream rollers that convey the supplied medium through the conveyance path to the position where the media is printed or otherwise processed.[0005]Such conveyance devices must be able to accurately control the conveyance speed of the medium from the downstream rollers in order to apply the printing or other process to the conveyed mediu...

AI Technical Summary

Benefits of technology

[0008]A conveyance device, a printing device, and a media conveyance method according to the present invention enable conveying sheet media using two sets of rollers to a process position while eliminating the effect of back tension on the downstream rollers without increasing device size.

[0011]In another aspect of the invention, determination of the starting time preferably delays the starting time of the downstream roller relative to the upstream roller.

Problems solved by technology

Such control is difficult, however, if there is back tension from the upstream side pulling on the medium at the downstream rollers.

However, consistently controlling media conveyance appropriately as conveyance conditions change is a problem with the technology taught in JP-A-2008-56367 because the drive time is advanced or the paper feed distance is increased in the same way regardless of the current conditions.

As a result, if control is always based on the same fixed values, slack in the medium between the upstream rollers and downstream rollers may be lost, or excess slack may allow the medium to rub against parts disposed along the conveyance path, and back tension maybe applied to the downstream rollers.

Another problem is that device size must be increased in order to maintain excess slack at all times so that slack is not eliminated and prevent slack media from touching parts along the conveyance path.

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