DE2921120C2 - Ink ribbon for a thermal printing device - Google Patents

Description

The invention relates to an ink ribbon for a thermal printing device according to the preamble of the patent claim 1.

Such an ink ribbon is known from DE-OS 28 39 852 In the thermal printer described there for multicolor printing, color record-forming materials for different are on a carrier web Colors in numerous, arranged on the carrier web in a repeating pattern Areas provided which are formed by rows of strips extending transversely to the direction of transport are.

From US-PS 39 84 809 a thermal printer for monochrome printing with a fixed Known print head in which the heat generating elements are arranged in a row. Should with this Device are printed in multiple colors, so it is necessary to have several individually arranged ink carriers to be provided.

From DE-OS 22 41 925 a writer is known in which a multi-colored registration for simultaneous Different signals are represented by placing a top layer on top of a coated one Recording medium is broken through so that the underlying carrier material at these points becomes visible. A separation of the carrier material and the recording medium is not intended.

The present invention is based on the object that from DE-OS 28 39 852 known ink carrier tape to develop in such a way that a high-quality multi-color printing is possible.

According to the invention, this object is given by what is specified in the characterizing part of claim 1 Feature solved.

The color spots within a segment advantageously have the three basic colors and the color Black.

An exemplary embodiment of the invention is described in detail below with reference to the drawing. It shows

F i g. 1 is a perspective view of a thermal printing device;

Fi g. Figure 2 is a front view on an enlarged scale Ink ribbon;

FIG. 3 is an enlarged view of a portion of a printhead associated with the one shown in FIG. 2 ink ribbon shown is used.

In Fig. 1 is a multi-color thermal transfer and single pass printing apparatus generally denoted by 10 is a web 12 of smooth paper or the like and an ink ribbon moving at the same time 14 are drawn over an elongated printhead 16. The web 12 of the recording medium is fed from a supply reel 18, runs under a support roller 20 and then through a clamping point between a pair of output feed rollers 22, 24 rotating in opposite directions Ink ribbon 14 having a pattern of different colored, record-forming materials on its upper side 15 carries, moves from a supply reel 26 to a take-up reel 28 and migrates in the process via a print head 16. As they pass under the support roller 20, the recording medium comes and the ink ribbon are in contact with each other and are positioned across their entire width between the printhead and the support roller are pressed together. The roller 20, the spools 18, 26, 28 and the rollers 22, 24 are in one suitable support frame rotatably mounted, which is made of green

which has been omitted for clarity in the drawing. The print head 16 is also on the support frame mounted in a manner that allows for an adjustment of the pressure applied against the webs 14, 12 and a Allows alignment with respect to the carrier web

The supply reel 18, the support roller 20 and the output feed rollers 22, 24 are set in rotation by suitable drive means 30, with drive means 32 for supply and take-up spools 26, 28 each perform the same function. As later in more detail is discussed, the web 12 and ribbon 14 over the printhead 16 in a first Operation at the same speed and in a different operation at different speeds drawn. The printhead 16, which includes a plurality of thermal elements, is provided with a Power supply and connected to control logic circuits 34 for the selective actuation of the elements ensure synchronous with the movement of the ink ribbon 14. To enable such synchronization, are the circuits 34 in a suitable manner with the drive devices 32 already mentioned tied together.

In accordance with the invention, the ink ribbon 14 contains a mosaic pattern of various thermally transferable record-forming colored materials, or "inks", on the surface that contacts the web 12 of the recording medium, i.e., the top 15. Such a pattern is shown (greatly enlarged) in FIG. The pattern shown contains discrete, separate spots 36 of four differently colored inks arranged in rhombic cells, a segment 38 being indicated by a dot-dash line. Each segment contains a yellow ink spot 36Y, a cyan spot 36C, a magenta spot 36Λί, and a spot 366 of black ink. The segments are arranged side by side in parallel rows which extend across the belt 14, that is, perpendicular to their direction of transport. One of the rows is shown in FIG. 2 denoted by a bracket 40.

Suitable color record-forming materials include known compositions of both the types used in conventional sublimation printing as well as those that soften or melt when heated to a certain temperature and onto a recording medium by differential Adhesion or diffusion are transferred. The preferred material for the ink ribbon is

3 4

one with good thermal resistance and good gene becomes, if the corresponding »black« thermithermal Transmission properties used It see element is energized. Such should be as thin as the mechanical registration can be achieved in several ways Strength and the dimensions required, for example with a servo-driven Application stability tolerates Characteristic 5 printhead alignment mechanism based on time stamps Carrier materials are polyester films ids Mylar, poly-responsive, which are printed on the ink ribbon, ester-coated paper and silicone-coated pa- Another possibility is to use it pier, which are between 25.4 and 76.2 u.m in thickness. a timing gear-like tape transport mechanism. The thermally transferable materials are duich Ει is also obvious that the web 12 and the color offset printing, Gravure printing or other conventional 10 carrier tape 14 over the print head 16 with the same Ge printing process, which should wander the necessary spot pattern speed, if a good picture quality can, brought to the carrier tape. quality should be preserved. This can be achieved by a

As in Fig. As shown in Fig. 3, the printhead 16 includes a suitable adjustment of the drive means 30 and 32 errei strips 42 made of heat-resistant insulating material, pre- pared in order to essentially cover the web and the belt preferably a ceramic part with low thermal conductivity to set 15 identical running speeds, ability A double set of thermal ele- ments- In a printing device that has a print head and

th 44 extends lengthwise along the top of a tessellated ribbon of paint of the straight face 43 of the strip. The thermal elements are of the type described, the image resolution is limited in the arrangement of the floor plan and in the dimensions by the dimensions of the printhead color patch segments similar to the thermally transferable patches 36 20, which form the basic image-forming unit on the surface of the ink ribbon 14. You are educate. For example, the colored spots on the colored belly are arranged in segments of four. Each element carrier tape 14 squares of 228.6 μίτι with 25.4 μΐη between 44 in a printhead cell is the same color as the space. The printhead 16 has thermal elements corresponding to the ink spot in the segment of the tray with similar dimensions. Because the distance is assigned to the intermediate band. For example, if the segments indicated by 25 spots of the same color in adjacent line-dotted outline lines at 46 are 279.4 μm, the maximum achievable resolution is a "yellow" thermal element 44 Y, approximately a "cyanization" 50 color elements per 2.539 cm in the uncolored "element 44C, a" magenta "element in the most extreme case (images with one color). Higher resolution / and a "black" thermal element 443. The printhead 16 contains a single row 48 of such dimensions in the dimensions of the printhead and segments. Color stain cells can be achieved.

Each of the thermal elements on strip 42

is with two electrical conductors on the surface 43. 2 sheets of drawings

connected, a supply line 50 and a common busbar 52. The busbar, 35
Supply lines and thermal elements can be formed on the substrate using known thick film or thin film techniques.
A suitable method is described, for example, in US Pat. No. 4,037,315. After the formation of the 40
Conductor tracks and the thermal elements will be the
Strip 42 connected to a metallic support plate 54 which contains fastening and positioning elements, not shown, for the printhead.

In operation, the printing device 10 (FIG. 1) is acted upon
the circuit 34 hits selected thermal elements 44 in synchronism with the movement of the web 12 and 12
of the ink ribbon 14 along the print head 16 with
Energy. The elements are energized by pulses of electrical current through them via the 50th
Bus bar 52 and its individual supply lines 50 are sent. During each
Pulse, an element supplied with energy is briefly heated to an elevated temperature, with a
"Hot spot" is created on the upper surface 45. 55
Heat penetrates from the element through the belt 14 and 14
causes the colored material to be transferred from
a spot 36 overlying the element to the recording medium web 12.

Multi-colored representations are enhanced by energy
drove to selected groups of thermal elements in
in the rows 48 as each row 40 of multi-spot segments on the ink ribbon 14 passes over the printhead in succession. As can be seen
plays maintaining good registration 65
between the carrier tape and the printhead
this mode of operation plays an important role, so that for
For example, a black spot from tape 14 transferred

Claims (2)

Patent claims: 1. Ink carrier tape for a thermal printing device, wherein the heat transferable, differently colored material is arranged in regularly repeating, mutually adjacent segments, characterized in that each segment (38) mosaic-like colored patches (36 V, 36C, 36B, 36M) of different Color includes 2. Ink carrier tape according to claim 1, characterized in that the color spots (36 V, 36C, 36ß, 36M) within a segment (38) have the three primary colors and the color black.