Transport device, recording device, and medium transport method

Patent metadata

Field	Value
Publication number	US-11465868-B2
Application number	US-201916555841-A
Country	US
Kind code	B2
Filing date	Aug 29, 2019
Priority date	Aug 31, 2018
Publication date	Oct 11, 2022
Grant date	Oct 11, 2022

Abstract

A control device of a transport device includes a control unit configured to control a roll motor for rotating a first rotary shaft on which a medium is held and a transport motor for rotating a first driving roller, a tension detection unit configured to derive, for each tension detection cycle, a detected tension value of a tension applied to a tension adjustment portion of the medium, and a tension F/B unit configured to calculate a tension F/B correction amount by feedback control based on a deviation between a target tension and the detected tension value. The control unit is configured to calculate a driving force by the roll motor based on the tension F/B correction amount, and control the roll motor based on the driving force.

First claim

What is claimed is:

1. A transport device comprising:
a holding unit configured to rotatably hold a roll body formed by winding a medium;
a rotary driving unit configured to impart, to the holding unit, a driving force in a rotation direction of the roll body;
a transport unit disposed downstream from the holding unit in a transport direction of the medium, the transport unit being configured to feed, downstream in the transport direction and for each predetermined transport cycle, the medium unwound from the roll body;
a transport driving unit configured to drive the transport unit;
a control unit configured to control the rotary driving unit and the transport driving unit;
a tension detection unit configured to derive, for each tension detection cycle that is shorter than the transport cycle, a detected tension value that is a tension applied to a portion of the medium between the holding unit and the transport unit; and
a tension feedback unit configured to calculate, each time the detected tension value is detected, a tension feedback correction amount by feedback control based on a deviation between the detected tension value and a target tension that is a target value of the detected tension value, wherein
the control unit is configured to calculate, for each tension detection cycle, the driving force by the rotary driving unit based on the tension feedback correction amount to control the rotary driving unit based on the driving force by the rotary driving unit.

2. The transport device according to claim 1 , comprising a storage unit configured to store a transition of the target tension in the transport cycle, wherein
when n is a natural number equal to or greater than 1 and corresponds to an ordinal number of the tension detection cycle,
the tension feedback unit is configured to, when the tension detection unit derives the detected tension value for an n tension detection cycle in the transport cycle, read out, from the storage unit, the target tension corresponding to the n tension detection cycle, and calculate the tension feedback correction amount by feedback control based on a deviation between the detected tension value for the n tension detection cycle and the target tension that is read out from the storage unit.

3. The transport device according to claim 1 , comprising:
an eccentricity profile generating unit configured to perform an eccentricity measurement process for measuring eccentricity of the roll body held by the holding unit, and the eccentricity profile generating unit configured to generate an eccentricity profile based on an eccentricity state of the roll body measured in the eccentricity measurement process; and
a tension feedforward unit configured to calculate, for each tension detection cycle, a tension feedforward correction amount by feedforward control based on the eccentricity profile generated by the eccentricity profile generating unit, wherein
the control unit is configured to calculate, for each tension detection cycle, the driving force by the rotary driving unit based on the tension feedback correction amount and the tension feedforward correction amount to control the rotary driving unit based on the driving force by the rotary driving unit.

4. The transport device according to claim 3 , wherein
in the eccentricity measurement process, the eccentricity profile generating unit is configured to generate the eccentricity profile based on a transition of a load current flowing in the transport driving unit with respect to a change in a rotation angle of the roll body, in a state where the rotary driving unit outputs a constant driving force substantially and a transport amount of the medium for each transport cycle is constant substantially.

5. The transport device according to claim 1 , comprising:
a transport speed deriving unit configured to derive, for each speed detection cycle that is shorter than the transport cycle, a detected transport speed value, the detected transport speed value being a transport speed of the medium fed downstream in the transport direction by the transport unit; and
a speed feedback unit configured to calculate a speed feedback correction amount by feedback control based on a deviation between a target transport speed that is a target value of the transport speed of the medium and the detected transport speed value derived by the transport speed deriving unit, wherein
the control unit is configured to calculate, for each speed detection cycle, a driving force by the transport driving unit based on the speed feedback correction amount to control the transport driving unit based on the driving force by the transport driving unit.

6. The transport device according to claim 5 , comprising a speed profile storage unit configured to store a speed profile that is a transition of the target transport speed over time in the transport cycle, wherein
the speed feedback unit is configured to read out, from the speed profile stored in the speed profile storage unit, the target transport speed corresponding to a time in the transport cycle,
the speed profile includes
an acceleration segment in which the transport speed of the medium increases over time substantially,
a constant speed segment that follows the acceleration segment and in which the transport speed of the medium is constant over time substantially, and
a deceleration segment that follows the constant speed segment and in which the transport speed of the medium decreases over time substantially, and
the tension feedback unit is configured to, when the speed feedback unit performs feedback control based on the target transport speed in the constant speed segment of the speed profile, reduce, as compared to when the speed feedback unit performs feedback control based on the target transport speed in a segment other than the constant speed segment of the speed profile, a gain of feedback control for calculating the tension feedback correction amount.

7. A recording device, comprising:
the transport device according to claim 1 ; and
a recording unit configured to perform recording onto a portion of the medium transported by the transport device, the portion being located downstream from the transport unit in the transport direction.

8. A medium transport method comprising:
providing, a transport device including a holding unit configured to rotatably hold a roll body formed by winding a medium, a rotary driving unit configured to impart, to the holding unit, a driving force in a rotation direction of the roll body, a transport unit disposed downstream from the holding unit in a transport direction of the medium, the transport unit being configured to feed the medium, unwound from the roll body, downstream in the transport direction for each predetermined transport cycle, and a transport driving unit configured to drive the transport unit;
deriving, for each tension detection cycle that is shorter than the transport cycle, a detected tension value that is a tension applied to a portion of the medium between the roll body and the transport unit;
calculating, each time the detected tension value is derived, a tension feedback correction amount by feedback control based on a deviation between the detected tension value and a target tension that is a target value of the detected tension value; and
calculating a driving force by the rotary driving unit based on the tension feedback correction amount calculated, to drive the rotary driving unit based on the driving force by the rotary driving unit.

Assignees

• Seiko Epson Corp

Inventors

• Hamano Ryo
• Hayashi Toru

Classifications

• B65H2515/31

  Tensile forces · CPC title

• B65H2801/12

  Single-function printing machines, typically table-top machines · CPC title

• B65H18/103

  Reel-to-reel type web winding and unwinding mechanisms · CPC title

• B65H23/198

  motor-controlled {(Controlling electrical drive motors therefor)} · CPC title

• B65H2513/11

  angular · CPC title