Printer for marking strips

Abstract

A printer is provided for printing marking strips having a plurality of marking elements for marking electric devices which can be arranged next to one another. Each of the marking elements has a marking plate with at least one writing field which can be printed with information such as writing. The printer has a rotatably mounted feed shaft which can be driven by a motor and a printing head. The rotatably mounted feed shaft has at least one section which is provided with protrusions and which rests directly against the marking strip while the feed shaft is rotated such that the advancing speed of the marking strip is synchronized with the circumferential speed of the feed shaft.

Claims

1. A printer for printing synthetic plastic marking strips formed of a first material and a second material which is harder than said first material, comprising (a) a rotatably mounted feed shaft which is driven by a motor; and, said feed shaft including at least one protrusion section formed as a saw-toothed interlock having a first diameter, said feed shaft protrusion section engaging and interlocking with the marking strip second material while said feed shaft is rotated to create a plurality of permanent indentations in the marking strip second material and to advance the marking strip in a linear direction at an advancing speed which is synchronized with a circumferential speed of said feed shaft; and (b) a printing head arranged adjacent to said feed shaft for printing on said marking strip first material.

2. The printer according to claim 1, wherein said protrusion section rests directly against said marking strip while said feed shaft is rotated, said permanent indentations creating a positive engagement between said feed shaft and the marking strip to synchronize the advancing speed of the marking strip with the circumferential speed of said feed shaft.

3. The printer according to claim 1, wherein said feed shaft includes at least two protrusion sections formed saw-toothed interlocks, respectively, which are axially offset and engage and interlock with the marking strip in different areas with a defined pressure while said feed shaft is rotated.

4. The printer according to claim 3, wherein said saw-toothed interlocks of said protrusion sections have a different diameter, respectively.

5. The printer according to claim 4, wherein said saw-toothed interlocks are arranged at a periphery of each section.

6. The printer according to claim 5, wherein said feed shaft has circumferential tooth-less sections.

7. The printer according to claim 3, wherein the pressure applied by said feed shaft to the marking strip is controlled to insure that said saw-toothed interlocks each press into the marking strip second material while the marking strip is advanced.

8. A printer for printing marking strips, comprising (a) a rotatably mounted feed shaft which is driven by a motor, said feed shaft including at least one protrusion section formed as a saw-toothed interlock having a first diameter, said feed shaft protrusion section engaging and interlocking with the marking strip while said feed shaft is rotated to create a plurality of permanent indentations in the marking strip and to advance the marking strip in a linear direction at an advancing speed which is synchronized with a circumferential speed of said feed shaft wherein said feed shaft has circumferential tooth-less sections which accommodate latch lugs of a latch contour of the marking strip without contact while the marking strip is advanced (b) a printing head arranged adjacent to said feed shaft.

9. The printer according to claim 8, wherein the marking strip is formed of at least one plastic material.

10. The printer according to claim 8, wherein said interlocking sections include a shoulder which guides the latch lugs of the marking strip.

11. A printer assembly, comprising (a) a printing head; (b) a synthetic plastic marking strip to be printed by said printing head, said marking strips including a first portion formed of a first material which receives printed indicia from said printing head and a second portion formed of a second material which is harder than said first material for subsequent attachment to an item to marked; and (c) a rotatably mounted feed shaft which is driven by a motor, said feed shaft including at least one protrusion section formed as a saw-toothed interlock having a first diameter, said feed shaft protrusion section engaging and interlocking with the marking strip second material while said feed shaft is rotated to create a plurality of permanent indentations in the marking strip second material and to advance the marking strip in a linear direction at an advancing speed which is synchronized with a circumferential speed of said feed shaft.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Other objects and advantages of the invention will be described in greater detail with reference to the accompanying drawings in which:

(2) FIG. 1 is a perspective view of a printer for printing multiple marking strips;

(3) FIG. 2a is a sectional view of a first embodiment of a marking strip and FIG. 2b is a sectional view of a further embodiment of a continuous marking strip;

(4) FIGS. 3a and 3b are sectional and front views, respectively of terminal blocks arranged next to one another with an inserted marking strip;

(5) FIG. 4 is a partial front view of a roller and a printing head with a continuous marking strip of the printer of FIG. 1;

(6) FIG. 5 is an enlarged detail view of the roller and the printing head with the continuous marking strip of FIG. 4;

(7) FIG. 6 is a sectional side view of the roller and the printing head with the continuous marking strip of FIG. 5; and

(8) FIG. 7 is a bottom view of the roller and the printing head with the continuous marking strip of FIG. 4.

DETAILED DESCRIPTION

(9) FIG. 1 is a simplified illustration of a printer 1 for printing continuous marking strips 2. Marking strips 2 are used for marking electric devices which can be arranged next to one another, such as terminal blocks as shown in FIG. 3a and FIG. 3b. The printer may have further components, such as a cover or the like, which are not shown.

(10) Printer 1 is preferably designed as a direct thermal printer or a thermal transfer printer. Alternatively, printer 1 may also be intended for other printing methods, such as ink jet or laser printing.

(11) Printer 1 has a printing head 3 preferably arranged above a feed shaft 4. Marking strip 2 is advanced between these two elements. Printing head 3 is preferably spring-loaded—in FIG. 1 from top to bottom—and presses marking strip 2 onto feed shaft 4. As such, feed shaft 4 also rests against marking strip 2 with a predetermined or defined force.

(12) Feed shaft 4 may be inserted into two bearing seats 5a, 5b. Feed shaft 4 may further have respective bearings 6a, 6b—preferably one at each of its ends. With these bearings 6a, 6b, feed shaft 4 is rotatably mounted on printer 1. Further, feed shaft 4 has a gear 7, at least at one of its free ends, which can mesh with a corresponding mating gear (not shown). The mating gear is driven by a motor (also not shown) located within printer 1.

(13) Thanks to this drive, feed shaft 4 can be rotated. The rotating motion of feed shaft 4 is suitably controlled by a printer controller (not shown).

(14) The rotatably mounted feed shaft 4 has at least one interlocking section 8 which is shown by way of example only as being arranged in the middle between bearings 6a, 6b and which rests directly against marking strip 2 by a defined pressure force produced by printing head 3 when feed shaft 4 is rotated such that the advancing speed of marking strip 2 is synchronized with the circumferential speed of feed shaft 4. An advancing motion is produced in direction X corresponding to the main direction of extension X of marking strip 2. Instead of an interlocking section, another protrusion section may also be provided (not shown). As an example, instead of the interlock with teeth, the protrusion section may have differently shaped protrusions which may engage the material of the marking strip in a somewhat positive fit to advance it.

(15) This allows a precisely defined advancing movement of the marking strip during printing in this direction to be provided easily and cost-effectively. The print image is easily applied in the dedicated areas in the main direction of extension which is the same as the advancing direction.

(16) The interlocking section 8 will be described in greater detail further below.

(17) FIG. 2a and FIG. 2b show two exemplary embodiments of the continuous marking strip. Marking strip 2 has multiple marking elements 9 which are shown in FIG. 6. Each marking element 9 has a marking surface 10 with at least one writing field which can be provided with information such as writing. Preferably, the writing field is configured to be printed with printer 1.

(18) On the side facing away from the writing field, each marking element 9 may further have a latch contour 11 integrally formed with the respective marking plate 10 for latching attachment of a corresponding latch contour (not shown) of a corresponding electrical device. For this purpose, latch contour 11 has latch lugs. While this is advantageous, the invention is also suitable for marking strips without latch contours.

(19) Marking strip 2 is made of plastic and produced by an extrusion process, preferably a co-extrusion process, wherein preferred cross-sections can be derived as shown in FIG. 2a and FIG. 2b. Preferably, this extrusion process results in areas forming marking plate 10 with the writing surface upon completion being made of a first material that is softer than that of latch contour 11 which is made of a harder second material.

(20) For marking an assembly of terminal blocks 12 on a mounting rail, it is then only necessary to place marking strip 2 above the area of the latch contours of the terminal blocks which are arranged next to one another as shown in FIGS. 3a and 3b and then to press on the individual marking elements 9 from above such that secure latching of marking elements 9 to the terminal blocks is accomplished. The marking strip is cut from a continuous strip, such as on a reel, such that the number of marking elements 9a, b, c, . . . corresponds to the number of devices arranged next to one another which are to be marked. Thus, marking strip 2 of FIG. 2a or FIG. 2b is suitable for marking three devices arranged next to one another. However, many more devices arranged next to one another can be marked within a single operation.

(21) A detailed design of continuous marking strip 2 is described in DE 10 2015 109 020 A1. It should be noted that the marking strips could also be different in design.

(22) In FIG. 3a or FIG. 3b, the word “MAIN DRIVE” printed across devices as an example. Thus, the wording “MAIN DRIVE”, such as a drive motor powered with 3-phase alternating voltage L1 to L3 and having a neutral connection N and a protective ground terminal PE spans five devices, i.e. terminal blocks 12.

(23) In FIG. 4, feed shaft 4 is shown with interlocking section 8 and printing head 3 of printer 1. Between feed shaft 4 and printing head 3, a marking strip 2 to be printed is inserted in the area of interlocking section 8.

(24) Here, as an example, interlocking section 8 is positioned approximately or precisely centered on feed shaft 4 with respect to the longitudinal extension thereof. Interlocking section 8 has interlock 13 around its entire periphery. It may be designed as a saw-toothed interlock. Further, interlocking section 8 engages with a gap between the latch lugs of latch contour 1i formed by marking strip 2. In this area, a precise feed is advantageous.

(25) During rotating motion of feed shaft 4, at least one interlock 13 produces indentations in at least one area due to the pressure force preferably but not necessarily applied by printing head 3 to marking strip 2. The respective indentation 14 may be a permanent indentation 14 as shown in FIG. 7.

(26) Each tooth of interlock 13 creates these indentations during the rotating motion of feed shaft 4 in a base of latch contour 11.

(27) Preferably, this allows a positive fit to be easily created between marking strip 2 and interlock 13 or interlocking section 8, resulting in a precise feed.

(28) Next to interlocking section 8, feed shaft 4 has two respective tooth-less sections 15a, 15b of a small diameter arranged symmetrically with respect to the interlocking section.

(29) Small-diameter toothless sections 15a, 15b are designed such that the latch lugs of latch contour 11 may freely move therein without contact with respect to a radial direction and may be guided on both sides of a shoulder 16a, 16b of a respective additional interlocking section 17a, 17b with respect to an axial direction.

(30) The additional interlocking sections 17a, 17b also rest directly against marking strip 2 due to the pressure force created by printing head 3 while feed shaft 4 is rotated such that the advancing speed of marking strip 2 is synchronized with the circumferential speed of feed shaft 4 in additional areas of marking strip 2. Here, the interlocking sections rest against marking plates 10 from beneath and provide for precise feed of these elements directly in the proximity of the actual areas to be printed.

(31) For this purpose, the respective interlocking sections 17a, 17b preferably have an interlock 19 extending across its periphery. The latter may have a saw-toothed design.

(32) The interlocking sections 17a, 17b axially offset from the first interlocking section may each have a step 18a, 18b with another radius, such as a smaller radius, than that of interlocking sections 17a, 17b. On its periphery, each respective step 18a, 18b preferably has an interlock 20. The respective step 18a, 18b also rests directly against marking strip 2 in an area under the defined pressure force created by printing head 3 while feed shaft 4 is rotated such that the advancing speed of marking strip 2 is synchronized with the circumferential speed of feed shaft 4 in still another area such as at a part of the latch contour. What is essential is that one or more interlocks on different diameters may be used to perform an adjustment to the respective marking geometry to implement a feed motion of the marking strip as precisely as possible.

(33) While feed shaft 4 is rotated, each tooth of interlocks 19, 20 also creates a respective resilient or plastic deformation or indentation 21, 22 as shown in FIG. 7 in a lug of latch contour 11 or on the side of marking plate 10 facing away from the printable side of marking plate 10 due to the pressure force applied by printing head to mark strip, with which the respective interlock 19 or 20 engages such that a positive fit is created between marking strip 2 and the respective interlock 19, 20 or the respective interlocking section 17a, 17b, to insure a tolerance-free feed of marking strip 2 during printing.

(34) Not all of the protrusions or interlocks have to leave a permanent indentation. For instance, it may not be desirable to create permanent indentations which might affect the visual appearance in places such as at the sides of the marking strip which will be visible after attaching the marking strip to a device.

(35) At the axial external surfaces of each of the further axial interlocking sections 17a, 17b, feed shaft 4 may have a respective section 23a, 23b having a larger outer diameter than the interlocking sections with respect to interlocking sections 8, 17a, 17b. Thus, printing head 3 of printer 1 may be protected while no marking strip 2 is being printed.

(36) In FIG. 5, printing head 3 and feed shaft 4 are shown with the respective interlocking sections 8, 17a, 17b, shoulders 16a, 16b and steps 18a, 18b and interlocks 13, 19, 20.

(37) In FIG. 6, interlocks 13, 19, 20 and indentations in marking strip 2 which are formed by interlock 13 are shown.

(38) In FIG. 7, indentations 14, 22 formed by interlocks 13, 20 in marking strip 2 are shown. Marking elements 9 of marking strip 2 are also shown.

(39) While the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those of ordinary skill in the art that various changes and modifications may be made without deviating from the inventive concepts set forth above.