U.S. patent application number 14/167449 was filed with the patent office on 2016-06-23 for thermotransfer printer comprising a single sheet feeder.
This patent application is currently assigned to Avery Dennison Corporation. The applicant listed for this patent is Avery Dennison Corporation. Invention is credited to Johannes LENKL.
Application Number | 20160176198 14/167449 |
Document ID | / |
Family ID | 34965267 |
Filed Date | 2016-06-23 |
United States Patent
Application |
20160176198 |
Kind Code |
A1 |
LENKL; Johannes |
June 23, 2016 |
Thermotransfer Printer Comprising a Single Sheet Feeder
Abstract
The present invention concerns a thermotransfer printer for
printing print media having RFID labels, comprising a
thermotransfer printing unit, and a single sheet intake means. The
invention is further characterised by an RFID reading unit for
reading items of information from the RFID labels, wherein the RFID
reading unit is so connected to the thermotransfer printing unit
(70) that the thermotransfer printing unit (70) is controllable in
dependence on the items of information read out of the respective
RFID label.
Inventors: |
LENKL; Johannes; (Freising,
DE) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Avery Dennison Corporation |
Mentor |
OH |
US |
|
|
Assignee: |
Avery Dennison Corporation
Mentor
OH
|
Family ID: |
34965267 |
Appl. No.: |
14/167449 |
Filed: |
January 29, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11578905 |
Oct 20, 2006 |
8675240 |
|
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PCT/EP2005/004180 |
Apr 19, 2005 |
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14167449 |
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Current U.S.
Class: |
347/171 |
Current CPC
Class: |
B41J 3/44 20130101; B41J
3/407 20130101; B41J 11/008 20130101; G06K 17/0025 20130101; B41J
13/12 20130101; B41J 2/32 20130101 |
International
Class: |
B41J 2/32 20060101
B41J002/32 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 20, 2004 |
DE |
102004019070.4 |
Claims
1. A method of controlling a thermotransfer printer comprising the
steps of: providing a thermotransfer printing unit containing a
print head, a single sheet intake means and a RFID reading unit;
reading items of information out of RFID devices within RFID labels
with the RFID reading unit; and controlling the thermotransfer
printing unit in dependence on items of information read out of a
respective RFID label.
2. The method of claim 1 further comprising a step of directing the
printing head to lift off a RFID label when the RFID label is
inferred to be at the printing head by the RFID reading unit after
the step of controlling the thermotransfer printing unit.
3. The method of claim 1, wherein the RFID reading unit is
connected to the thermotransfer printing unit such that the
printing unit is controllable in dependence on items of information
read out of the respective RFID labels.
4. The method of claim 1 further comprising a step of inferring the
position of the RFID devices in RFID labels by measuring one of
signal intensity, transit time, or time delay by the RFID reading
unit after the step of reading the items of information out of the
RFID devices within the RFID labels.
5. The method of claim 1 further comprising a step of passing the
RFID labels through a tunnel guide into the thermotransfer printer
before the step of reading the items of information out of the RFID
devices within the RFID labels.
6. The method of claim 1, wherein the RFID reading unit
continuously emits signals calling on the RFID labels to send back
information.
7. The method of claim 1, wherein a pressure roller is disposed
beneath the printing head.
8. A method of controlling a thermotransfer printer comprising the
steps of: providing a thermotransfer unit containing a printing
head, a RFID reading unit, a single sheet intake means, a drive
roller, and a counterpressure backing roller; providing a print
medium with RFID labels wherein each RFID label has a RFID device;
passing the print medium conveyed by the single sheet intake means
through a tunnel guide into the thermotransfer printer; passing the
print medium between the drive roller and the counterpressure
backing roller and passing the print medium to the print head
wherein the print head applies pressure to the print medium and
applies items of information to the print medium; and lifting the
printing head off the print medium as soon as the RFID label in the
print medium reaches the printing head.
9. The method of claim 8, wherein a pressure roller is disposed
below the printing head.
10. The method of claim 8, wherein a control unit commands the
printing head to execute a given printing application.
11. The method of claim 10, wherein the printing application is
stored within each RFID label.
12. The method of claim 8, wherein the counterpressure roller is
fixed to a holder arm.
13. The method of claim 8, wherein the reading unit is beneath the
tunnel guide.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a division of U.S. application
Se. No. 11/578,905 filed Apr. 19, 2005, which is a 371 of
International Application No. PCT/EP2005/004180 filed Apr. 19,
2005, which claims priority to DE 10 2004 019 070.4, filed on Apr.
20, 2004, all of which are incorporated herein by reference in
their entireties.
FIELD OF THE INVENTION
[0002] The invention concerns a thermotransfer printer for printing
on print media having RFID labels. The thermotransfer printer has a
thermotransfer printing unit and a single sheet intake means.
BACKGROUND OF THE INVENTION
[0003] Sheet intake devices of the most widely varying kinds are
regularly employed in printers in order to feed individual sheets
from a stack of sheets, whereby an orderly printing operation is
guaranteed. Previously known individual sheet intake devices are
designed to transport the most widely varying sheet formats into
the printer. In particular individual sheet intake means are
suitable for also transporting flat articles such as plastic cards
to the thermotransfer printing unit. Unlike sheets of paper plastic
cards of that kind are very stiff and can quickly break if they are
bent. Therefore previously known thermotransfer printers with a
single sheet intake means have been developed, which ensure
reliable guidance for a print medium to be transported, without
causing deformation of the print medium, that is to say the sheet
or the plastic card, during transport. Such a single sheet intake
means is known in particular from European patent specification EP
0 694 488 B1.
[0004] A thermotransfer printer with single sheet intake means is
suitable in particular for printing on print media which include
RFID labels. An RFID label comprises a transponder and an antenna.
The RFID label is adapted to transmit an identification as a
reaction to a received electromagnetic signal. In other words, it
is possible to have access to the RFID label by means of a
writing/reading unit. The identification of the RFID label
comprises a sequence of digits which uniquely identify the
respective label. When a label of that nature is fixed to a product
the product can thus be identified therewith. That is effected by
means of the reading/writing unit. Information transmission between
the RFID label and the reading unit is effected by way of radio
frequency signals. That term is also used in particular to mean
signals in the Gigahertz range and also in the range of some
hundred Hertz. Infrared radiation and visible light do not belong
thereto for the advantage of the RFID label is precisely that
information exchange is substantially independent of temperature
fluctuations or light conditions. The transponder and the antenna
are in particular let into special sheets of paper or are
integrated into a plastic card. The purpose of the transponder is
to automatically generate a response to a demand or a received
signal. In particular the identification of the RFID label is sent
in the transponder, as a reaction to a received signal. The
transponder represents in particular a data storage means as the
identification of the RFID label is stored therein. Usually the
transponder comprises a transistor circuit which is embodied by a
microchip. The microchip has to be protected from environmental
effects, in particular heat and applications of pressure. Transport
of the print medium with the RFID label by means of the single
sheet intake means firstly provides that the print medium including
the RFID label is not bent in the printing operation.
[0005] When printing on print media which contain RFID labels,
specific problems arise. In particular it is necessary to ensure
that the RFID labels are not in any way damaged or adversely
affected in the operation of printing on the print media. The
connection between the transponder and the antenna breaks
relatively easily. It is however absolutely necessary for the RFID
label to operate. Such a break can occur in particular if the
printing head of the thermotransfer printer applies an excessive
pressure or an excessive temperature to the transponder and/or the
antenna of the RFID label.
[0006] Accordingly the object of the invention is to ensure that
there is no possibility of damage to the RFID labels when printing
on print media containing RFID labels.
BRIEF SUMMARY OF THE INVENTION
[0007] That object is attained by the printer as set forth in
accompanying claim 1. This involves a thermotransfer printer with a
thermotransfer printing unit and a single sheet intake means.
[0008] The printer also has an RFID reading unit. The reading unit
is suitable for actuating RFID labels in order to read out items of
information, in particular the identification of the RFID labels.
The RFID reading unit can thus monitor at any time whether print
media with RFID labels is being fed or printed upon at the present
time. If there are no print media present, the RFID reading unit
does not receive any signal subsequently to the emission of a
query. If the RFID reading unit has received items of information
from an RFID label, in particular the identification of the RFID
labels, then the thermotransfer printer can be controlled in
dependence on the items of information from the RFID label. The
printer therefore automatically learns whether attention is to be
paid to RFID labels which are present, in the printing operation,
whereby damage to the RFID labels can be avoided.
[0009] Preferably there is provided a control unit which obtains
items of information received from the RFID reading unit. The
control unit controls the print in dependence on the received items
of information. The thermotransfer printing unit normally naturally
has a CPU and a working memory for controlling the printing unit.
The CPU can function as a control unit which processes the items of
information from the RFID reading unit. The CPU calls up items of
information from the RFID reading unit. The information received
from an RFID label can include in particular the nature of the
print medium and of the RFID label. The thermotransfer printer
according to the invention can thus appropriately react to the
nature of the print medium and the label in order to avoid damage
to the labels. The control unit provides that the printing heads
are lifted off the print medium in the region of the RFID label so
that the printing heads do not collide with the label. In
particular items of information regarding the location of the label
on the print medium and information as to whether printing can be
effected in the region of the RFID label could be contained in the
label. Finally, it would even be possible for the RFID label to
specify what motif is to be printed on the print medium. That
however would require the RFID labels having a relatively large
memory. They would be relatively complex and expensive.
[0010] Preferably the RFID label transmits only its identification
(ID). The identification is a sequence of digits which uniquely
identifies the RFID label. All further items of information
concerning the RFID label as well as the print medium and possibly
the motif to be printed are stored in an identification memory of
the control unit. If the control unit is embodied by the CPU and
the working memory of the thermotransfer printing unit, the
arrangement has a non-volatile memory (for example a hard disc) as
the identification memory. All identifications of RFID labels to be
printed are stored in the identification memory. Precisely one set
of commands is associated with each identification. The set of
commands includes all instructions with which the printer according
to the invention is to be actuated in order to ensure trouble-free
printing. Items of information concerning the motif to be printed
can possibly also be called up by way of the identification. It
would thus be additionally possible to ensure that the current
print media are correctly printed in the printer. The print media
themselves so-to-speak control implementation of the printing
operation. For that purpose it is only necessary for the RFID
reading unit to regularly query the identification of the RFID
labels.
[0011] If a plurality of RFID labels are in the
transmitting/receiving region of the RFID reading unit, then the
RFID reading unit simultaneously receives a plurality of
identifications of the respective RFID labels as a reaction to an
enquiry. The RFID reading unit must therefore be put into the
position of separating the signals received from the RFID labels. A
number of access methods are known from radio technology, which
permit a plurality of transmitters to be able to send their data to
a single receiver, namely the RFID reading unit: SDMA (space
division multiple access), TDMA (time domain multiple access), FDMA
(frequency domain multiple access) and CDMA (code division multiple
access). As in RFID technology the transponders only have a limited
capacity and are to be produced as favourably as possible, the TDMA
is primarily suited as the procedure involved. If the time axis is
divided into a number of time portions and each RFID label
transmits in another time portion, the signals received from the
RFID reading unit can be separated in respect of time. In the case
of FDMA the signals transmitted by the RFID labels are transmitted
on different carrier frequencies. The carrier frequency signal is
then amplitude-modulated in order to transmit information.
Separation of the received signals in the RFID reading unit is then
effected by frequency filters. It is also possible to use a
combination of TDMA and FDMA.
[0012] Because of the fact that the transponders cannot detect
whether further transponders are reacting to an enquiry from the
RFID reading unit, collisions can nonetheless occur. They must be
recognised and treated by the reading arrangement. Manchester
encoding is a suitable signal encoding process which allows the
RFID reading unit to detect whether a plurality of RFID labels are
transmitting signals. Thereupon it is necessary to ensure by means
of anti-collision procedures that the RFID labels transmit their
identifications by means of one of the above-mentioned access
processes, for example TDMA, in such a way that they can be
separated by the reading unit. There are deterministic and
probabilistic algorithms for that purpose.
[0013] A possible deterministic algorithm is the tree trunk
algorithm. When that algorithm is used then, in each enquiry step,
the RFID reading unit calls on all RFID labels which can be reached
to send back their identification if the identification if part of
a predetermined group of identifications. If a plurality of RFID
labels respond to an enquiry, that is to say if a collision is
detected, the reading unit, at the next enquiry, reduces the number
of elements from the predetermined group. The group is reduced in
size until only one RFID identification is sent back. The
corresponding RFID label is thus recognised. The algorithm proceeds
in a similar manner with the remaining identifications until all
RFID labels are identified.
[0014] A possible probabilistic process for separating the RFID
labels is the Aloha process. In the Aloha process the reading unit
makes a number of time intervals available to the RFID labels. Each
of the RFID labels randomly selects a time slot in which it
responds. If the number of possible time slots is very much greater
than the number of responding labels, there is a low probability
that no one of the labels alone responds during a time slot. In
other words it is improbable that there is no time slot in which
only one label responds. The process for recognising the RFID
labels comprises a plurality of enquiry rounds. As soon as the RFID
reading unit has recognised an RFID label the corresponding
transponder of the RFID label is switched into the mute condition
so that in the next enquiry no response is received from that
transponder.
[0015] When the reading unit has recognised a plurality of labels
it can ascertain from the reduction in the received signal
intensity from the RFID labels how far the labels are away from the
RFID reading unit. As the labels are conveyed or moved along a
given path through the printer, it is possible to infer the
position of the respective labels. In that way it is possible at
any time to monitor which printing media are being printed upon.
Position detection could also be effected on the basis of the
detected transit time or time delay to an enquiry from the reading
unit.
[0016] The tree trunk process is particularly suitable for RFID
label recognition. As the speed at which the RFID labels are
transported through the printing unit is known, the RFID reading
unit can predict on the basis of those items of information which
of the detected RFID labels, at the next enquiry, will have left
the transmitting/receiving region of the RFID reading unit, and in
particular which of the known RFID labels are received. The RFID
labels in respect of which it is expected that they are still
within the transmitting/receiving region of the reading unit in the
next enquiry are switched mute at the next enquiry. When a fresh
RFID label is conveyed into the transmitting/receiving region of
the RFID reading unit, that is the sole responding RFID label as
all other RFID labels are switched into the mute condition. The
complication and expenditure involved in identifying the RFID
labels is thus greatly restricted.
BRIEF DESCRIPTIONS OF THE DRAWINGS
[0017] An embodiment of the present invention is described
hereinafter with reference to the accompanying Figure.
[0018] FIG. 1 shows a thermotransfer printer in accordance with the
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] The thermotransfer printer shown in FIG. 1 includes a single
sheet intake means. The single sheet intake means has a carrier 2
which can be moved upwardly and downwardly in the direction of the
arrow. Print media to be printed upon are stacked one above the
other on the carrier 2. The plane of the carrier is perpendicular
to an abutment plane 6 which is disposed in the plane of the
drawing and which serves as a sheet guide. A second abutment 7 is
disposed perpendicularly to the plane of the carrier and the first
abutment plane 6. The carrier 2 transports the print media
continuously upwardly so that they can be successively delivered to
the thermotransfer printer by way of a separating edge 11. A
transport device 8 in roller form is arranged above the separating
edge 11 and the transport device 8 in roller form is pressed onto
the uppermost print medium and pushes it over the separating edge
11 into the thermotransfer printer. The transport device is
connected to a pivot shaft 12 by way of an arm. The pivot shaft is
perpendicular to the abutment plane 6. The separating edge 11 is
arranged below the upper abutment of the pivot arm 10 in such a way
that there is a sufficiently large space for the print medium to be
passed through by means of the transport device 8 between the upper
abutment and the separating edge. The spacing between the
separating edge and the upper abutment is adjustable so that
different print media can be conveyed by means of the single sheet
intake means to the thermotransfer printing device.
[0020] The print medium conveyed by the single sheet intake means
firstly passes through a tunnel guide 16 into the thermotransfer
printer. The print medium includes an RFID label. Arranged beneath
the tunnel guide 16 is an RFID reading and/or writing unit. As soon
as the print medium with the RFID label passes the RFID reading
unit the print medium is detected by the RFID reading unit. For
that purpose the RFID reading unit continuously emits signals,
calling on the RFID label to send back its identification.
[0021] The print medium finally passes between a drive roller 18
and a counterpressure backing roller 20. The drive roller 18 is
shown in cross-section. It is cylindrical and transports the print
medium to a printing head 22 of the illustrated thermotransfer
printing unit. The two rollers 18 and 20 receive the print medium
between them. The counterpressure roller 20 provides that the
contact pressure of the drive roller 18 is sufficient to convey the
print medium. The counterpressure roller 20 is fixed to a holder
arm 21 pivotable about an axis. The counterpressure roller 20 is
biased towards the drive roller 18. If however there are
irregularities or projections on the print medium then the
counterpressure roller 20 is not an obstruction to the irregularity
but pivots yieldingly away from the arm 21.
[0022] Finally the print medium with the RFID label passes to the
printing head 22. The illustrated printing head is a corner edge
printing head. A printing head of that kind applies a relatively
low pressure to the print medium. That therefore reduces from the
outset the risk of the RFID label being damaged by the printing
head. The printing head 22 applies items of information to the
print medium by means of the known thermotransfer printing process.
Disposed below the printing head 22 is a pressure roller 23 which
transports the print medium beneath the printing head 22 out of the
thermotransfer printing unit.
[0023] As soon as the RFID reading unit 14 identifies an RFID
label, it controls the printing head 21 by way of a control unit
(not shown). The control unit is embodied by the CPU and the
working memory of the thermotransfer printing unit. The control
unit commands the printing head 22 to execute a given printing
application which is stored with the identification of the
respective RFID label. In that case care is taken to ensure that
the printing head 22 is lifted off the print medium as soon as the
RFID label in the print medium reaches the printing head 22. In
that way the RFID label cannot be damaged by the printing head
22.
* * * * *