Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J11/00—Devices or arrangements  of selective printing mechanisms, e.g. ink-jet printers or thermal printers, for supporting or handling copy material in sheet or web form
  • B41J11/0005—Curl smoothing, i.e. smoothing down corrugated printing material, e.g. by pressing means acting on wrinkled printing material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J13/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in short lengths, e.g. sheets
  • B41J13/02—Rollers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J15/00—Devices or arrangements of selective printing mechanisms, e.g. ink-jet printers or thermal printers, specially adapted for supporting or handling copy material in continuous form, e.g. webs
  • B41J15/16—Means for tensioning or winding the web
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/315—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material
  • B41J2/32—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads
  • B41J2/325—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by selective application of heat to a heat sensitive printing or impression-transfer material using thermal heads by selective transfer of ink from ink carrier, e.g. from ink ribbon or sheet

Definitions

• the present invention is directed to thermal printing.
• a printer apparatus and method is disclosed for printing on receiver media without damaging the media.
• Preferred embodiments of the present invention incorporate the use of a less aggressive capstan roller design along with a softer pinch roller to eliminate impression marks in the thermal receiver.
• a tension differential across the capstan is controllably decreased.
• the capstan uses a straight (longitudinal) knurl pattern with ridges running along the length of the roller parallel to its axis of rotation, as shown in FIGs. 4A-B.
• the ridges are disposed at a frequency of 10 to 30 ridges per inch. The depth of these ridges being at least 10 microns.
• the pinch roller of a preferred embodiment of the present inventions is composed of a steel shaft covered with an elastomeric material having a shore-A durometer ranging from 20 to 60, with a 50 micron Teflon sleeve covering the elastomer.
• the tension of the receiver between the receiver roll and the capstan, region 108, produced during a printing phase should be maintained at more than 50% of the tension existing between the capstan and the thermal print head, region 107. This amounts to less than 50% tension differential across the capstan roller.
• a preferred embodiment of the present invention includes a printer comprising a thermal print head for applying thermal media onto a receiver, a capstan roller disposed between the thermal print head and a supply of receiver media for controlling a feed of the receiver to the print head, and means for maintaining a minimum tension of the receiver between the supply of receiver and the capstan roller.
• the capstan roller is uniquely knurled with a longitudinal knurl pattern having a depth of at least about 10 microns and does not contain sharp points that may penetrate the receiver. Rather, it comprises a high traction, non- marking surface.
• a pinch roller adjacent the capstan roller forms a nip for the receiver.
• the pinch roller comprises an elastomeric material thereon having a shore-A durometer ranging from about 20 to about 60, preferably closer to about 40.
• the means for maintaining tension comprises a motor and a torque limiter that drives the roll holding the supply of receiver.
• the motor and torque limiter can be applied to a second pair of rollers between the supply of receiver and the capstan roller.
• the receiver is maintained in a taut state in a region of the receiver adjacent the capstan roller. This controlled tension helps to maintain a printing registration within a preselected tolerance.
• Another preferred embodiment of the present invention comprises a drive system with a first pair of rollers forming a nip for feeding a receiver medium toward a print head.
• a receiver supply roll has a supply of the receiver wound thereon and supplies the receiver to the first pair of rollers.
• a means for maintaining a minimum tension acts upon the receiver in a region between the receiver supply roll and the first pair of rollers.
• the means may include a control means for controllably rotating the receiver supply roll for maintaining the minimum tension, or it can include a second pair of rollers between the receiver supply roll and the first pair of rollers.
• the second pair of rollers can control a tension of the receiver between the second pair of rollers and the first pair of rollers in response to a movement of the receiver through the first pair of rollers.
• FIG. 1 illustrates a receiver feed mechanism
• FIG. 2 illustrates a receiver feed mechanism with tension control rollers.
• FIGs. 3A-B illustrate views of a sharp point capstan roller.
• FIGs. 4A-B illustrate views of a longitudinal knurled roller.
• FIG. 5 illustrates in-track data points using different modifications.
• FIG. 6 illustrates cross-track data points using different
• FIG. 7 illustrates impression mark data points using different modifications.
• FIGs. 8A-B illustrate in-track and cross-track registration performance using different receiver tensions.
• FIG. 1 there is illustrated a portion of a thermal printer's drive system.
• a roll 106 of receiver 105 is fed through a thermal printer 100 as shown by the receiver advancing past thermal print head 101, as fed by thermal roller 102, pinch roller 104 and capstan roller 103.
• Dye donor web 109 (partially illustrated) is applied onto the receiver in predetermined patterns, as is well known in the art.
• the receiver is iteratively reversed and printed during several color applications of the dye donor web in the predetermined patterns.
• Tension in approximate region 107 relative to approximate region 108 affect an ability of the capstan and pinch rollers to effectively control movement of the receiver therethrough.
• a preferred embodiment of the present invention comprises a less aggressive capstan roller 103 design, as is illustrated in FIGs.
• a knurled pattern provides a spike free configuration that does not perforate a surface of receiver 105 as would the spiked configuration of the capstan roller shown in FIG. 3A-B.
• impression marks are not formed in the thermal receiver as it passes between capstan and pinch rollers 103, 104.
• a tension differential across the capstan in approximate regions 107 and 108 is decreased. By increasing tension in the receiver on the roll side of the capstan 108 during printing, an acceptable color to color image registration is produced. This increase in the tension in approximate area 108 reduces the tension differential across capstan roller 103.
• control of the tension in approximate region 208 of the receiver can be achieved by providing a properly sized clutch (torque limiter) on the output of the drive motor for receiver roll 206 (not shown).
• the clutch control can be used to adjust tension in the receiver in approximate region 208.
• An alternative method for controlling the tension in approximate region 208 of the receiver includes adding rollers 210 which would likewise be driven by a motor with a properly sized clutch on its output. This would reduce the length of controlled tension approximate region 208 to that approximate portion indicated by the dashed line bracket 208a.
• the capstan 203 uses a straight knurl pattern with ridges running along the length of the roller parallel to its axis of rotation as shown in FIGs. 4A- B.
• the ridges are disposed at a frequency of 10 to 30 ridges/cm at a depth of at least 10 microns.
• the pinch roller is composed of a steel shaft covered with an elastomeric material with a shore -A durometer ranging from 20 to 60, with a 50 micron Teflon sleeve covering the elastomer.
• This preferred embodiment is a softer and thinner version of conventional elastomer roller covers. A softer pinch roller aids in eliminating marks in the receiver but often results in more slippage of the receiver due to lower traction.
• Controlling tension in the receiver on both sides of the capstan roller can reduce or eliminate slippage.
• the tension of the receiver between the receiver roll and the capstan, approximate region 108, produced during printing should be more than about 50% of the tension existing between the capstan and the thermal print head, approximate region 107. This percentage is higher than the unregulated tension commonly existing in thermal printers.
• the clutched motor is designed to provide a predesigned load, which controls an amount of tension applied to the receiver at approximate region 108.
• Manual trial and error clutch adjustment can be fine tuned by monitoring performance of the printer, then manually leaving the clutch set at the desired adjustment point. This procedure can be undertaken during the design phase to establish a factory setting. Depending on the design of the printer, characteristics such as thermal head drag and capstan traction might require more or less tension between the receiver roll and the capstan to achieve proper image registration.
• the receiver roll diameter ranges from about 7 inches diameter when full to about 3.5 inches when depleted for the spool diameter, which should be compensated by controlling motor speed and torque during depletion of the receiver media.
• a full roll weighs approximately 5-6 pounds. If the clutch is driving the paper roll, the RPM of the motor output must be determined based on the smallest possible roll diameter during the printing cycle and on the largest possible diameter during the rewind cycle to insure that the clutch slips and maintains tension properly. If the clutch is driving a second pair of rollers, for example, the alternate rollers 210, the roll diameter is not a concern.
• the clutch operates by attaching part of it to the shaft and another concentric part attached to a drive component such as a gear or pulley. These two parts of the clutch are coupled to each other only by friction which produces a limited amount of torque when slippage of one half relative to the other occurs. Typically, this friction coupling is adjustable for controlling an amount of mechanically transmitted torque.
• the torque can be varied in a stepwise fashion until the color to color registration is within specification.
• Some possible ways to vary the torque to determine an acceptable value are to use an adjustable clutch, a series of fixed- value clutches or a pulley and weight system attached to the paper roll. This same technique can be used whether the clutch is driving the paper roll or a second pair of rollers.
• the precision of the tension control will depend on the gripping capability of the capstan roller. The less the gripping capability, the more tension control is required.
• the data point at head load spring 505 value 3.2, pinch roller spring 504 value 3.8, and pinch roller 503 value 40 shore A durometer shows an in-track performance of approximately -18 thousandths of an inch.

Landscapes

• Handling Of Sheets (AREA)
• Electronic Switches (AREA)
• Handling Of Continuous Sheets Of Paper (AREA)
• Delivering By Means Of Belts And Rollers (AREA)
• Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=45787358

Family Applications (1)

Country Status (7)

Families Citing this family (2)

Citations (3)

Family Cites Families (13)

• 2011
  • 2011-02-23 US US13/032,897 patent/US8810620B2/en active Active
• 2012
  • 2012-02-20 JP JP2013555468A patent/JP6030074B2/ja active Active
  • 2012-02-20 CN CN201280007483.7A patent/CN103429434B/zh not_active Expired - Fee Related
  • 2012-02-20 WO PCT/US2012/025784 patent/WO2012115893A1/en not_active Ceased
  • 2012-02-20 EP EP12706988.8A patent/EP2678163B1/en active Active
  • 2012-02-20 BR BR112013018698A patent/BR112013018698A8/pt not_active Application Discontinuation
  • 2012-02-22 TW TW101105909A patent/TWI566956B/zh not_active IP Right Cessation

Patent Citations (3)

Also Published As

Similar Documents

Legal Events