DE19644905A1 - Print head guiding device - Google Patents

Abstract

A print guide mechanism having parallel first and second guide rods 14,16, and a carriage assembly 12 designed to move along the guide rods. The carriage assembly in a preferred embodiment comprises roller bearing assemblies 26,28,74 being secured to the frame and being arranged so as to engage the rods with one assembly pivotally mounted to the frame so as to compensate for parallel misalignment between the guide rods and is biased for applying a loading force so that positive engagement is provided between the guide rods and the roller bearing assemblies. In another embodiment at least one of the roller bearing assemblies has an outer engaging surface made of a material having a modulus of elasticity less than the modulus of the guide rod which it engages.

Description

The invention relates to a printhead guide device with a first and a parallel arranged second guide rod and an ent slide that can be moved along the guide rods.

Append at the same time as considered to be included here by name Current patent application US-08 / 123,839 describes a method and a pre direction for exposing photosensitive media with multiple light sources. In this patent application, an LED print head is on the outer surface of a arranged rotating rotor, the light on a light-sensitive material throws, for example on photo paper. With such a device are very strict Performance requirements in terms of positioning and / or speed to maintain the speed of the translation device. The movement must be at high Ge accuracy to avoid the well-known streak artifacts that from human eye can be clearly perceived. These artifacts are typically caused by different positioning errors within the digital printing device caused. For linear translation devices Two main components are responsible for the accuracy of the movement. The the first is the drive unit, in the case of which it is attached at the same time Patent application is a spindle with a smaller bolt than Thread diameter was cut and from a rotary stepper motor is driven. The second main component is the leadership unit, based on which the carriage runs linearly on a predetermined path. Typically the slide is arranged over roller elements with two parallel to each other  connected waves that allow the carriage to travel along the linear Track to move.

The invention causes a very ge for the linear translation of the carriage accurate and smooth slide movement, its construction and assembly is relatively inexpensive, and which minimizes the problem of streak artifacts, that can be caused by such devices.

According to one aspect of the invention, a printhead guiding device is provided with a first and a second guiding rod arranged in parallel therewith and a carriage movable along the guiding rods, the carriage comprising:
a frame
at least two mutually associated roller bearings which are fastened to the frame and are arranged such that they can be brought into engagement with the first guide rod in order to bring about a linear movement of the slide along the first guide rod,
at least one upper bearing unit which is arranged on the frame in such a way that it engages with the second guide rod,
a first bracket unit having at least one lower roller bearing unit, the at least one upper and lower roller bearing being positioned such that it engages with the intermediate second guide rod, and wherein the first bracket unit is pivotally supported on the frame such that a parallel misalignment between the guide rods is compensated for, and which is biased to exert a loading force so that the guide rods and the roller bearings come into positive engagement with each other.

According to another aspect of the invention, a printhead guide device is provided with a first and a second guide rod arranged in parallel therewith and a carriage movable along the guide rods, the carriage comprising:
a frame
a plurality of roller bearing units which are attached to the frame such that the carriage is movable along the guide rods, at least one of the roller bearing units having an outer engagement surface which is made of a plastic material whose modulus of elasticity is less than that of the guide rod with which it is engaged.

According to another aspect of the invention, a printhead guide device is provided with a first and a second guide rod arranged in parallel therewith and a carriage movable along the guide rods, the carriage comprising:
a frame
at least two associated guide rod engaging elements which are fastened to the frame and arranged such that they can be brought into engagement with the first guide rod in order to bring about a linear movement of the slide along the first guide rod,
at least one upper guide rod engagement element which is arranged on the frame men such that it engages with the second guide rod,
a first bracket unit having at least one lower guide rod engaging member, the at least one upper and lower guide rod engaging member being positioned to engage the intermediate second guide rod and the first bracket unit being pivotally supported on the frame that a parallel misalignment between the guide rods is compensated for, and which is biased to exert a loading force so that the guide rods and the guide rod engaging elements positively engage with each other.

The invention is described in the following with reference to the drawing Examples explained in more detail.

It shows  

Fig. 1 is an exploded isometric view of a carriage unit OF INVENTION to the invention,

Fig. 2 is a side view of the complete slide unit of FIG. 1 approximately rods of the carriage showing the arrangement with respect to two Füh,

Fig. 3 is a perspective view of the slide unit of FIG. 1, in a different perspective

Fig. 4 is an enlarged, partial perspective view of FIG. 3, the part is cut as to represent, as the lower holding approximation unit is fixed to the frame,

Fig. 5 is an exploded sectional view of a detail used in the device of FIG. 1 bearing unit,

FIG. 6a shows the measured Schlittenpositionierfehler at a Schlittenein integral with roller bearings made of stainless steel, which run on stainless steel rod guide,

Fig. 6b the measured slide positioning error for composite plastic roller bearings that run on stainless steel guide rods

Fig. 7 is an exploded isometric view of an OF INVENTION to the invention, the modified carriage unit,

Fig. 8 is an exploded isometric view of an OF INVENTION to the invention, the modified carriage unit,

Fig. 9 is a side view of the slide unit of FIG. 8 showing the positioning of the carriage with respect to two guide rods,

Fig. 10 is an enlarged view of one of the skid units to Anord the carriage unit voltage on the guide rods used

Fig. 11 is a side view taken along line 11-11 of Fig. 10,

FIG. 12 is a view comparable to FIG. 10 showing one of the degrees of freedom in which the skid unit can move, and

Fig. 13-15 various other degrees of freedom in which the skids unit can move.

Referring to FIGS. 1-4 according to the invention a printhead is guiding device 10 will be described. The printhead guide device 10 can be used in particular in an LED printing device which is provided for exposing a light-sensitive material (for example photographic paper), as described in more detail in the aforementioned copending patent application US-08 / 123,839. The guide device can, however, also be used in various other printers where light-sensitive material is exposed by a print head traveling above it. For example, a laser printhead can be used, but this example is not intended to be limiting in order to expose a light-sensitive material such as photographic film, photographic paper, thermal media or an electrostatic surface. The apparatus 10 includes a carriage unit 12, and two pa rallele guide rods 14, 16 on which the carriage unit 12 is moved to the linear movement along a to the axes of the guide rods 14, 16 running parallel to the web. The carriage unit 12 comprises a frame 17 and is fastened to the guide rods 14 , 16 in such a way that the movement of the carriage unit 12 is only possible in a degree of freedom which is parallel to the guide rods 14 , 16 . The translation of the carriage unit 12 along the guide rods 14 , 16 can be achieved by any desired device. In the illustrated embodiment, this is effected by a adjusting screw 18 and a stepper motor 20 which are attached to the printing device (not shown) in which the printhead device 10 is used. The adjusting screw spindle 18 engages in the carriage unit 12 such that the rotation of the adjusting screw spindle 18 causes the carriage unit 12 to move along the guide rods 14, 16 . In the embodiment shown, a rotating print head 19 is provided to print on a light-sensitive material, in particular photo paper or photographic film, which is later developed in known, conventional processing machines. However, the carriage unit 12 can accommodate any desired type of printing devices in order to move them over the photosensitive material. The adjusting screw 18 can be attached to the device in a known, conventional manner. The adjusting screw spindle is preferably attached to the carriage unit 12 in such a way that the carriage unit 12 moves and / or is positioned precisely at a substantially constant linear speed. A suitable example of the engagement of the lead screw in the drive device is described in US-A-5,392,662, which is incorporated herein by reference. Of course, any other ge desired coupling device can be provided, which is able to carry the rotary motion on the adjusting screw for the purpose of translational loading movement of the carriage unit 12 along the guide rods 14 , 16 .

The carriage unit 12 is arranged on the guide rod 14 via a plurality of roller bearing units 22 , 24 , 26 , 28 . The roller bearings 22 , 24 , 26 , 28 are arranged such that the roller bearings 22 , 24 are at a first position and are spaced on the carriage such that the guide rod 14 is engaged therebetween. Likewise, Rollerlagereinhei th 26 , 28 are attached to the carriage at a second position spaced from the first position and arranged on the frame 17 such that the guide rod 14 is also engaged therebetween. The roller bearing units 22 , 24 , 26 , 28 engage in the guide rod 14 such that a linear movement of the carriage unit 12 along the guide rod 14 will be effective.

The carriage unit 12 is also arranged on the guide rod 16 by the mounting units 30 , 32 . The bracket unit 30 includes a retaining member 34 which is attached to the frame 17 such that the retaining member 34 can be pivoted about an axis perpendicular to the guide rod 14 , as shown in the figure by arrow 35 . In the particular embodiment shown, the holding element 34 is fastened with a holding pin 36 which has a head 37 , a shaft region 38 adjacent to the head 37 and a threaded end 39 . The shaft area 38 is dimensioned such that the holding element 34 can pivot about the holding pin 36 , and the threaded end 39 is so dimensioned that it can engage in the threaded hole (not shown) in the frame 17 , so that the holding unit 30 on the frame 17th is attached. The Hal extension element 34 is also provided with two spaced upper roller bearing units 44 , 46 to support the frame 17 against the guide rod 16 .

The bracket unit 32 is attached to frame 17 and comprises a support frame 48 with a bracket member 50 and a U-shaped element 51 with a base member 52 and two upstanding projections 53rd The mounting unit 32 is arranged on the frame 17 in such a way that a pivoting movement takes place about an axis running essentially parallel to the direction of travel of the slide unit 12 , as indicated by arrow 75 . For this purpose, a holding pin 55 is provided with a shaft region 57 which is guided through two aligned openings 61 in the projections 53 . The support pin 55 also has an opening 59 through which a support pin 63 leads ge and which fastens the support frame 48 to the frame 17 . The holding pin 63 can be attached to the frame 17 in the desired manner.

The U-shaped member 51 is pivotally on the bracket member 50 angeord net, so that the bracket member 50 can be moved substantially perpendicular to the direction of travel of the carriage unit 12 . The U-shaped element 51 is fastened to the holding element 50 by means of a holding pin 58 which has a head 60 , a shaft region 62 and a threaded end 64 . The shaft region 62 is constructed in such a way that it is passed through an opening 66 in the holding element 50 such that the threaded end 64 engages in a threaded bore 67 in the U-shaped element 51 (see FIG. 4). A Fe derelement 68 is attached to the frame 17 with the aid of the retaining pin 69 , which is passed through an opening 71 in the spring element 68 and engages in a (not shown) threaded hole in the frame 17 . The spring element 68 is designed so that it engages in a bearing surface 70 which is assigned to each of the projections 52 . The spring element 68 also serves as the Fe to build a bias against the bearing surface 70 so that the support frame 48 can pivot in the direction indicated by the arrow 54 . Two lower roller bearing units 72 , 74 are attached to the lateral ends of the support member 50 . The bracket units 30, 32 are positioned the art, that the guide rod 16 between the roller bearing units 44, 46, 72 detects, 74, and that the carriage unit 12 along the rod can move approximately Füh sixteenth As can be seen in the figure, the mounting units 30 , 32 can pivot in the directions indicated by the arrows 35 and 75 , respectively, so that they engage in the guide rod 16 in such a way that a parallel misalignment of the guide rods 14 , 16 is avoided. Since the spring element is attached to frame 17 68, exerts Federele element 68 a loading force on the associated roller bearing units 72, 74, so that the guide rod is acted upon 16 with a force pass from which the rest of the roller bearing units form fit with the respective guide rod is engaged.

The roller bearing units 22 , 24 , 26 , 28 , 44 , 46 , 72 , 74 are each attached to their corresponding elements. Referring to FIG. 5, the construction of a roller bearing unit 22 according to the invention 26, 28, 44, 46, 72 is shown in detail, the construction for the rest of the roller bearing units 24, 74 is representative. The roller bearing unit 22 comprises a radial inner bearing 80 which is seated in an outer sleeve 82 . In the preferred embodiment, the outer liner 82 is made of a composite plastic and has an outer engagement surface 83 . The material of the bushing 82 preferably has a modulus of elasticity which is smaller than the modulus of elasticity of the guide rod with which it is engaged. The plastic material of the bushing 82 was selected according to the modulus of elasticity, which is relatively high for a plastic material, which is preferably at least 0.7 × 10⁶ psi. However, a large number of other composites or additives-provided thermoplastics which have a comparatively high modulus of elasticity would also be suitable for the invention. A high modulus of elasticity is desirable for the liner in order to minimize the deformation of the plastic liner when it is acted upon by a compressive force against its corresponding guide rod. In the preferred embodiment shown, the guide rods 14 , 16 each consist of stainless steel, which has a modulus of elasticity of approximately 28.0 × 10⁶ psi, whereas the outer liners of each roller bearing unit consist of a composite plastic. In the illustrated embodiment, the liner is made of 6/6 nylon with 20% carbon fibers and has a modulus of elasticity of approximately 2.4 × 10⁶ psi. The plastic material should not be made from a material whose elastic modulus is too close to that of the bars with which it is engaged. The modulus of elasticity of the plastic material should preferably not be more than 10% above that of the guide rod with which it is engaged. Thus, the modulus of elasticity of the bushing 82 in the embodiment shown is not greater than 2.8 × 10⁶ psi.

The roller bearing units can be attached to frames 17 or to mounting units 30 , 32 in any desired manner. In the illustrated preferred embodiment, a collar screw 90 is used to secure the roller bearing units to their respective support members.

An important aspect of the invention is that the plastic bushing 82 of the roller bearing unit, which is in roller engagement with the guide rod, gives the slide a certain degree of damping and smoothness. For use with the slide unit, roller bearing units with outer stainless steel bushings were first examined. It turned out that when using stainless steel roller bearing units in conjunction with stainless steel guide rods, the linear positioning accuracy of the slide unit was significantly worse than when using roller bearing units with plastic bushings in connection with stainless steel guide rods.

Referring to FIGS. 6a and 6b a comparison of the Translationsverhal is shown least between a carriage unit with stainless steel roller bearing units and a carriage unit with plastic roller bearings units, each Schlit teneinheit runs on stainless steel guide rods. FIG. 6a shows the use of stainless steel roller bearing units in combination with stainless steel guide rods, Fig. 6b shows the use of plastic roller bearing units in combination with stainless steel guide rods. The curves shown in FIGS. 6a and 6b were generated by calculating the Fourier transformation of the slide positioning error, a laser interferometer being used for the measurement. The stainless steel guide rods and the stainless steel roller bearing units had a modulus of elasticity of approx. 28 × 10⁶ psi. The plastic roller bearing units consisted of an outer bush made of 17% Kevlar filled with 6/6 nylon (purchased from AL Hyde Co. under the brand name "Hydlar Z"). The nylon plastic had a modulus of elasticity of approx. 0.9 × 10⁶ psi. As shown by the vertical lines in Fig. 6a, there was a significant positioning deviation compared to the use of plastic roller bearing units in connection with the guide rods. A significant amount of unwanted spectral energy between 0.5-4.0 cycles / mm occurred in the stainless steel roller bearing units, which is not present when roller bearing units with composite plastic liners are used, as shown in Fig. 6b. This shows smooth running or damping, by means of which the plastic roller bearing units contribute to a good translational behavior of the slide. Incidentally, the surface quality (ie roughness) of the contact surface of the plastic bushing should be kept as small as possible in order to achieve optimum performance. The surface roughness of both the plastic and the stainless steel roller bearings is preferably less than approximately 81.3 μm. The runout of the roller bearing unit should be kept to a minimum in order to achieve optimal performance. The runout deviation is preferably less than approximately 0.0127 mm.

Be fit to the point stress between the roller bearing units and the Füh approximately rods to minimize the shape and configuration should Eingreifflä the surface 83 with respect to the guide rod with which it is engaged, attached. This adjustment is shown with reference to FIG. 5. The radius R1 of the engaging surface 83 should be equal to or slightly larger than the radius R2 of the outer surface of the guide rods. Although R1 and R2 can be identical, R1 should preferably be slightly larger to compensate for tolerance deviations. R1 is preferably in the range from approximately 101 to 110% of R2. In the illustrated embodiment, R1 is approximately 103% of R2. Since the outer bushing of the bearings has a smaller modulus of elasticity than the stainless steel rods, the plastic bushings 82 are compressed more than the stainless steel. The load is distributed over a larger concave area, which reduces the contact voltage between the guide rod and the plastic bushing. When using the configuration according to the invention, there was no visible sign of wear on the guide rods or the plastic bushing surfaces after a slide travel of 2 540 000 cm. This was in stark contrast to the considerable wear on the guide rods and bearing surfaces, which was only visually detectable after 508,000 cm when stainless steel roller bearing units and stainless steel guide rods were used.

Referring to FIG. 7, a guide according to the invention, modified apparatus is shown 110th The guide device 110 is comparable to the print head guide device 10 , the same reference numerals designating the same parts. In the guide device 110 , only a single roller bearing unit is assigned to each mounting unit 30 , 32 . The mounting unit 32 furthermore makes it possible to compensate for a parallel misalignment between the guide rods 14 , 16 and applies a prestressing force to the guide rod 16, as a result of which all roller bearing units come into positive engagement. However, this embodiment has the disadvantage with respect to the previous embodiment that higher contact forces are applied to each of the roller bearing units 120 , 122 . This becomes important when the weight of the sled plays a role. The use of more than one roller bearing unit with each of the mounting units 30 , 32 as shown in the embodiment of FIGS . 1-4 enables the use of sledges of higher weight. By pivoting the support units 30 , 32 in the directions indicated by the arrows 35 , 75 , the problem associated with the use of spaced roller bearing units is minimized or eliminated.

Referring to Fig. 8 and 9, a print head carrying device of the invention, modified is illustrated 200th The printhead guide device 200 is similar to the printhead guide device 10 , with the same numerals denoting the same parts and operations. The printhead guide device 200 comprises a carriage unit 212 which is arranged on the guide rod 14 via a plurality of guide skid units 222 , 224 , 226 , 228 . The guide runners 222 , 224 , 226 , 228 are arranged such that the guide runners 222 , 224 are in a first position on the carriage unit 212 , so that the guide rod 14 is engaged therebetween. Likewise, guide skid units 226 , 228 are attached to the carriage at a second position spaced apart from the first position and arranged on the carriage unit 12 such that the guide rod 14 is also engaged therebetween. The guide runners 222 , 224 , 226 , 228 engage in the guide rod 14 in such a way that a linear movement of the slide unit 12 along the guide rod 14 is brought about.

The carriage unit 212 is likewise arranged on the guide rod 16 on the basis of the holder unit 30 , 32 in almost the same way as the carriage unit 12 from FIG. 1. In contrast to this, instead of the roller bearing units 44 , 46, two guide skid units 244 , 246 are used which touch and carry the carriage unit 212 . Although the roller bearing units 22 , 24 , 26 , 28 cause an accurate and smooth movement in standard print formats, it was found that with large print formats the distance L between the carrier elements (as shown in FIG. 9) can lead to strip artifacts during exposure. Another problem with roller bearings is that when dust, paper or other particles are deposited on the guide rods, artifacts can occur when the roller units run over the particles, the artifacts possibly being increased due to the large distances L. The guide skid units used in this embodiment minimize or eliminate this problem in devices for large print formats and correspondingly long distances L. Another advantage of the guide skid units is that they allow a greater degree of freedom in the movement between the carriage and the guide rods.

Referring to FIGS. 10 and 11 is an enlarged view of a single guide runners NEN unit 222 is shown, how the carriage is disposed on the carriage unit 12 display. The other guide runners units 224, 226, 228 are struiert kon in the same manner as the guide runners unit 222 so that only a detailed description of a single Füh approximately skid unit is the 222nd The guide skid unit 222 includes a Fe derelement 230 , which is attached to a skid 232 . The spring element 230 is made of a material that can bear the load acting on the slide unit from the guide rods, but is sufficiently flexible to allow the desired bend. In the embodiment shown, the spring element 230 has a first mounting region 234 with two openings 236 , by means of which the spring element 230 can be fastened to the slide unit 212 with two screws 238 which engage in the threaded bores 241 in the slide unit 212 . The spring element 230 also includes a second mounting area 239 , which serves to secure the runner 232 to the mounting area 239 . In the illustrated embodiment, the holding area 239 comprises two openings 240 through which the spring element 230 can be fastened to the runner 232 with two holding screws 242 . However, the spring element 230 can be attached to the carriage unit 212 or to the runner 232 in any desired manner. The spring element 230 has a central, deformable bending region 243 . In the illustrated embodiment, the bending area 243 comprises two support members 246 , 248 , which form a V between the mounting areas 234 , 239 . The spring element 230 consists of cold-rolled steel, which has been tempered to achieve good spring properties.

The runner 232 has a contact surface 250 , as can best be seen in FIG. 13. This surface serves as a sliding and contact surface on the guide rod. The runner 232 is preferably made of a thermoplastic material with internal lubricants, which ensure low friction and low slip. A material suitable for the runners is acetal plastic with 18% Teflon and 2% silicone. A suitable material can be obtained from LNP Engineering Plastics, Inc. (Product No. KL-4540B). The guide skids can be manufactured by injection molding, preferably in the vicinity of the mounting area 239 of the spring element 230 , in order to obtain an integrated guide skid suspension unit which can dispense with further fastening elements. The radius RP of the contact surface 250 is somewhat larger than the radius R2 of the guide rod. The contact surface 250 reduces the point contact stress on the runner 232 .

It has been found that a guide skid manufactured according to the invention unit can travel over 5,080,000 cm while doing so has a decentration of the rotor axis of rotation of approx. 0.02286 mm, which ak is acceptable. In the tested environment, the guide runners have an Ra dius RP of approx. 10.49 mm, while the guide rod has a radius R2 of 9.25 mm.

Referring to Figures 12-15, various possible degrees of freedom of the skid assembly are shown. These degrees of freedom allow the runners to align themselves with the guide bar with which they are in contact, which will reduce wear over time. In particular, Fig. 12 shows the compensation of a parallelism error between the guide rod and the carriage unit, as denoted by θX. Referring to FIG. 13, the compensation of a Paral is lelitätsfehlers tung between the guide rod and the carriage unit in Rich θZ shown. In Fig. 14, the compensation with respect to an angular deviation between the guide rod and the carriage unit is shown, as shown by rotation about the Y axis θY. From this it can be seen that the guide skid units are originally in the Y and Z directions and still allow movement in all other directions for error compensation, so as to form a wear-reducing unit. The wear would otherwise cause artifacts with regard to the focusing of the optical system. This unit is also insensitive to a translational rocking. In addition, this robust design requires fewer components with critical tolerances.

Of course, the invention can and various other changes Modifications can be made, for example, without being concerned limited, the runners are made of any suitable material. Other suitable materials, such as thermoplastic materials, can be used with a carbon additive and internal teflon lubricants will. The higher stiffness due to the addition of carbon is likely to result in a lower rate over time Wear.

The device according to the invention brings about a smooth and precise position sledge with a long service life.

The numerous features and advantages of the invention are apparent from the detailed Description can be seen, the appended claims all these Merk Male and advantages of the invention cover the scope of the Erfin dung fall. Although some embodiments of the invention are shown and have been described, the invention is of course not limited to these, but can make numerous changes and modifications known to experts lungs are subjected so that the shown and described here details are not to be understood as restrictive, but in such a way that all relevant specialist obvious changes and modifications of Invention to be covered.

Reference list

10 printhead guide
12 slide unit
14 , 16 guide rods
15 , 50 mounting element
17 frames
18 adjusting screw spindle
20 stepper motor
22 , 24 , 26 , 28 , 44 , 46 , 72 , 74 , 120 , 122 roller bearing units
30 , 32 bracket units
34 mounting element
35 , 54 , 75 arrow
36 , 55 , 58 , 63 retaining pin
37 head
38 , 57 shaft area
39 thread end
40 , 59 , 66 , 71 bore
48 support frame
50 mounting element
51 U-shaped element
52 base part
53 vertical projections
60 head
61 aligned openings
62 shaft area
64 thread end
67 hole
68 spring element
70 storage space
80 radial bearings
82 , 87 liner
83 engaging surface
90 collar screw
110 guide device
200 print head guide
212 carriage unit
222 , 224 , 226 , 228 guide skid units
230 , 242 spring element
232 runners
234 , 239 bracket area
236 , 230 holes
238 , 242 screws
241 threaded holes
243 bending area
244 , 246 support elements
250 contact area

Claims (17)

1. printhead guide device ( 200 ) with a first and a parallel to it arranged second guide rod ( 14 , 16 ) and an ent long the guide rods movable carriage ( 212 ), characterized by :

• - a frame ( 17 ),
• - At least two mutually associated guide skid units which are fastened to the frame ( 17 ) and are arranged such that they are in engagement with the first guide rod in order to bring about a linear movement of the slide along the first guide rod,
• at least one upper guide skid unit arranged on the frame such that it comes into engagement with the second guide rod,
• - A first bracket unit with at least one lower Lagerein unit, the at least one upper guide skid unit and the lower roller bearing units are arranged such that they come into engagement with the intermediate second guide rod, and wherein the first bracket unit is pivotally mounted on the frame such that a parallel misalignment between the guide rods is compensated for, and which is biased to exert a loading force so that the guide rods and the roller bearing units come into positive engagement with each other.

2. printhead guide device ( 200 ) according to claim 1, characterized in that at least one of the guide skid units ( 222 , 224 , 226 , 228 ) comprises a spring element ( 230 ) and a skid ( 232 ) which engage with a guide rod located. 3. printhead guide device ( 200 ) according to claim 2, characterized in that the spring element ( 230 ) is made of a flexible spring steel. 4. printhead guide device ( 200 ) according to claim 1, characterized in that the runner ( 232 ) consists of a thermoplastic material with lubricants therein. 5. printhead guide device ( 200 ) according to claim 4, characterized in that the runner ( 232 ) consists of acetal with 18% Teflon and 2% silicone. 6. printhead guide device ( 200 ) according to claim 2, characterized in that the contact surface ( 250 ) of the runner ( 232 ) has a radius which is greater than the radius of the guide rod with which it is in contact. 7. printhead guide device ( 200 ) with a first and a parallel to it arranged second guide rod ( 14 , 16 ) and an ent long the guide rods movable carriage ( 212 ), characterized by:

• - a frame ( 17 ),
• - A plurality of mutually associated guide skid units ( 222 , 224 , 226 , 228 ) which are attached to the frame ( 17 ) in such a way that the carriage ( 212 ) can move along the guide rods, at least one of the guide skid units being a spring element ( 230 ) and has a runner ( 232 ).

8. printhead guide device ( 200 ) according to claim 7, characterized in that the plurality of guide skid units ( 222 , 224 , 226 , 228 ) comprises the following:

• - two first guide skid units assigned to each other,
• - Two second mutually associated guide skid units which are axially spaced from the first two guide skid units, the first and second two guide skid units being fastened and arranged on the frame ( 17 ) such that they are in engagement with the first guide rod in a linear manner Causing movement of the carriage ( 212 ) along the first guide rod
• at least one upper guide skid unit arranged on the frame such that it comes into engagement with the second guide rod,
• - A first mounting unit with at least one guide skid unit, the at least one guide skid unit being arranged in such a way that it comes into engagement with the second guide rod and the first mounting unit is pivotally mounted on the frame such that a parallel misalignment between the guide rods is balanced, and which is biased to exert a loading force so that the guide rods and the roller bearing units come into positive engagement with one another.

9. printhead guide device ( 200 ) with a first and a second guide rod arranged parallel thereto and a slide ( 212 ) movable along the guide rods, characterized by:

• - a frame ( 17 ),
• - A plurality of mutually associated guide skid units ( 222 , 224 , 226 , 228 ) which are attached to the frame ( 17 ) in such a way that the carriage ( 212 ) can move along the guide rods, at least one of the guide skid units having an outer surface ( 83 ) has, and wherein the guide skid consists of a plastic material whose modulus of elasticity is less than that of the guide rod with which it is engaged.

10. printhead guide device ( 200 ) according to claim 9, characterized in that the guide rods ( 14 , 16 ) each consist of a material which has a modulus of elasticity of approximately 28.0 × 10si psi, where against the outside of the guide skid consists of a material with a modulus of elasticity that is less than about 2.8 × 10⁶. 11. printhead guide device ( 200 ) according to claim 9, characterized in that the outer engagement surface ( 83 ) of the guide skid consists of a material having a modulus of elasticity which is not greater than 10% of the modulus of elasticity of the material from which the Management teams exist. 12. printhead guide device ( 200 ) according to claim 9, characterized in that at least one of the guide skid units has a skid which consists of a plastic material, the elasticity module is greater than or equal to 0.7 × 10⁶. 13. printhead guide device ( 200 ) according to claim 9, characterized in that the contact surface of the runner has a radius which is greater than the cross-sectional radius of the guide rod with which it is in engagement. 14. Printer with a movable carriage unit ( 12 ) to move a print head in such a way that a photosensitive material is written, characterized by:

• a first and a second guide rod ( 14 , 16 ) arranged parallel thereto,
• - A movable along the guide rods carriage unit ( 12 ), the carriage unit ( 12 ) having a frame ( 17 ), at least two mutually associated guide skid units, which are attached to the frame ( 17 ) and are arranged such that they with the first guide rod can be brought into engagement in order to bring about a linear movement of the slide along the first guide rod, at least one upper guide skid unit which is arranged on the frame in such a way that it engages with the second guide rod, a first mounting unit which has at least one Lower bearing unit, wherein the at least one guide rod is arranged such that it comes into engagement with the second guide rod, and wherein the first mounting unit is pivotally mounted on the frame such that a parallel misalignment between the guide rods is compensated for, and the preloaded is to exercise a loading force so that the guide rods and the Rol lenlager come into positive engagement with each other.

15. Printer according to claim 14, characterized in that the printhead comprises at least one light emitting diode. 16. Printer according to claim 14, characterized in that the lichtemp sensitive material includes photo paper. 17. Printer according to claim 14, characterized in that at least one of the roller bearing units has an outer liner made of a plastic material with a modulus of elasticity of 0.7 × 10⁶ psi or larger.