EP0992356B1 - Printing device - Google Patents

Description

The invention relates to a printing unit according to the preamble of claim 1.

Such printing units are used in particular in price marking devices and hand stamps. In their basic structure, they consist of several pressure belts or wheels, which can be adjusted manually by means of an adjustment button, so that selectable types of print can be brought into the printing position. After inking the printing types in the printing position with ink, which is usually done using a paint roller or ink pad, a print can be printed on an object - in particular a price label.

Such a ribbon printing unit has become known, for example, from EP 153651 A. In its basic structure, it consists of a housing in which an adjusting shaft is axially displaceable and rotatable. A slotted sleeve is slid over the setting shaft, on which several setting wheels are mounted coaxially side by side. Printing tapes carrying printing types are wrapped around the setting wheels. Since the adjusting shaft is provided with teeth that reach through the slots in the sleeve and engage in corresponding recesses on the inner circumference of the adjusting wheels, azimuthal Rotation of the setting shaft, the position of a printing belt can be adjusted, ie. the desired print type can be placed in the print position. By axially displacing the adjusting shaft, the adjusting shaft is brought into drive connection with one of the adjusting wheels. The axial position of the adjusting shaft is locked by a locking finger, which is made in one piece with the sleeve, and engages in locking recesses in the adjusting shaft. By means of a suitable pre-tensioning of the latching finger, the adjusting shaft locks in a position in which its teeth are engaged with an adjusting wheel.

In the prior art, the locking finger is thus made in one piece with the sleeve and is made of a plastic material. This embodiment is inexpensive, but has the disadvantage that the locking finger can only tolerate a certain number of displacements of the adjusting shaft and can then break off due to material fatigue. The disadvantageous consequence is that the entire printing unit and thus also the labeling device become unusable.

Starting from the state of the art, the invention is based on the problem of creating a printing unit which is distinguished by durability and reliability.

The object is achieved in a printing unit, with a housing, an axially displaceable adjusting shaft with recesses spaced apart in the axial direction of the adjusting shaft, a sleeve surrounding the adjusting shaft, the sleeve being provided with a latching finger which defines the axial position the setting shaft can be locked in each of the recesses of the setting shaft, solved in that the sleeve and the locking finger are made in two pieces.

The main idea is to provide two separate elements, namely a sleeve and a locking finger, which are manufactured separately and then assembled together, instead of a one-piece sleeve with locking fingers molded onto it. It is particularly advantageous if the locking finger is made of durable metal, while the sleeve can be made of plastic, which is characterized by being inexpensive and easy to process.

The advantages of the invention are primarily a greater durability and service life of the printing unit.

To fix the locking finger on the sleeve, it is recommended that the locking finger by a clip connection, ie. is attached to the sleeve by a snap fastening.

For this purpose, in particular a hook can be formed on the locking finger, which engages under a web of the sleeve, so that the web is clamped between the hook and the locking finger. This gives a fixation in the axial direction of the locking finger with respect to the sleeve, and with suitable, ie. Approximately matching dimensions of the web and the hook in the lateral (or azimuthal) direction also in the lateral direction of the locking finger. Of course, it is also conceivable to attach the web to the locking finger and the hook to the sleeve.

Furthermore, an extension that extends in the direction of the longitudinal axis of the sleeve and that extends through a recess in the sleeve can be formed on the locking finger. The function of the extension is essentially to prevent the locking finger from moving in the axial direction relative to the sleeve. With approximately identical dimensions of the extension and the recess in the lateral (or azimuthal) direction, a - second - fixation of the locking finger on the sleeve also results in the lateral direction. alternative the extension can be integrally formed on the sleeve, and the recess in the locking finger.

It is proposed that the locking finger have a first section, on the front side of which there is a rounded head which can be locked in the recesses of the adjusting shaft. In this embodiment of the invention, the material-intrinsic elasticity of the first section of the latching finger can cause the latching finger to be pretensioned in such a way that the spring force necessary for latching in the recesses arises. As a rule, the locking finger then has a second section, on which the hook and / or the extension are integrally formed.

• Figur 1: ein erfindungsgemäßes Druckwerk in einem Schnitt längs der Linie A-A von Figur 2;
• Figur 2: das Druckwerk der Figur 1 in einem Schnitt längs der Linie B-B von Figur 1;
• Figur 3: eine Ansicht einer Hülse mit daran befestigtem Rastfinger;
• Figur 4: eine Seitenansicht eines Rastfingers;
• Figur 5: eine Draufsicht auf den Rastfinger der Figur 4;
• Figur 6: einen Schnitt durch eine Hülse mit daran befestigtem Rastfinger; und
• Figur 7: eine schematische Seitenansicht eines Etikettiergeräts, in dem as erfindungsgemäße Druckwerk verwendet werden kann.

An embodiment of the invention is explained in more detail below with reference to the drawings. They show a schematic representation in

• Figure 1: an inventive printing unit in a section along the line AA of Figure 2;
• Figure 2: the printing unit of Figure 1 in a section along the line BB of Figure 1;
• Figure 3 is a view of a sleeve with a locking finger attached;
• Figure 4 is a side view of a locking finger;
• Figure 5: a plan view of the locking finger of Figure 4;
• Figure 6: a section through a sleeve with a locking finger attached; and
• FIG. 7: a schematic side view of a labeling device in which the printing unit according to the invention can be used.

The printing unit 10 shown in FIG. 1 contains a printing unit housing composed of two housing halves 12 and 14, in which a plurality of parallel arranged, around setting wheels 16 and Deflection wheels 18 which are guided around the printing area are accommodated with printing tapes 20. The printing unit 10 is intended in particular for use in hand-held labeling devices. The printing tapes 20 are not shown in FIG. 1 for reasons of clarity, but are clearly visible in FIG. 2. The print bands 20 alternately carry print types 22 and display types 24 on their outer circumferential surface. The assignment of the print types 22 to the display types 24 is carried out in such a way that print types 22 that are currently in the printing position on a deflection wheel 18 and display types 24 that pass through a window 26 arranged on the top of the housing is visible, each representing the same number, the same letter or the like. This means that it can be seen on the top of the housing through the window 26 which character can be printed on a recording medium with the print types 22 located at the bottom at the deflection edge.

As already mentioned, the pressure tapes 20 are guided around setting wheels 16 which are rotatably mounted on a sleeve 28. The sectional drawing of Figure 2 shows that three slots are made in the sleeve 28, which are open at the right end of the sleeve in Figure 1. Teeth 32, 34, 36, which are attached to an adjusting shaft 42, pass through these slots. The setting shaft 42 is slidably mounted in a bearing bushing 44 in the housing half 14. By displacing the setting shaft 42 in the axial direction, this shaft can be brought into a drive connection by engagement of the teeth 32, 34, 36 in corresponding recesses 46 in the hub regions of the setting wheels 16. The engagement of the tooth 36 in one of the recesses 46 of the setting wheel 16 can be seen in FIG.

At the end of the setting shaft 42 protruding from the housing, an operating button 48 is attached, with the aid of which the setting shaft 42 can be axially displaced on the one hand and rotated on the other hand. Due to the axial displacement of the settings shaft 42, the teeth 36 attached to it are first brought into engagement with the recesses 46 of an adjusting wheel 16 to be adjusted, and by rotating the adjusting shaft 42 the pressure band 20 which is guided around its outer circumference is then moved until a desired printing type 22 in Printing position is located below the deflection wheel 18. As already mentioned, the respective position of the print types 22 can be checked through the window 26 attached to the top of the housing. To achieve a drive connection between the pressure bands 20 and the setting wheels 16, the pressure bands 20 have teeth 50 on their inner surface, which engage in recesses 52 in the outer peripheral surfaces of the setting wheels 16.

In order to achieve a precise alignment of the plane of the teeth 32, 34, 36 with the level of the adjusting wheel 16 to be adjusted in each case, a locking mechanism is provided which ensures that the adjusting shaft 42 in its axial adjustment in each case in a clearly perceptible manner for the operator in positions engages, in which a clear drive connection is made with an adjusting wheel 16 to be adjusted. This latching mechanism comprises a latching finger 54 attached to the sleeve 28, which projects radially inward on the sleeve inner surface and engages in latching recesses 56 which are introduced in a region of the outer peripheral surface of the adjusting shaft 42. A locking recess 56 is provided for each of the setting wheels 16 mounted on the sleeve 28. If, in the arrangement of the individual parts shown in FIG. 1, in which the setting shaft 42 is engaged with the leftmost setting wheel 16, the setting shaft 42 is moved to the right so that it comes into engagement with the next setting wheel 16, for example, must first the force exerted by the latching finger 54 on the setting shaft 42 is overcome when it is moved upward out of the associated latching recess 56 in the illustration in FIG. 1; then it can then fall into the next recess 56, which occurs exactly when when the adjusting shaft 42 is engaged with the second dial 16 from the left.

As can be seen from FIG. 1, the setting shaft 42 extends in the section immediately adjacent to the actuating button 48 through a passage 44 which is attached to a conical cap 64. Among other things, this cap 64 has the task of ensuring a smooth covering of the upper part of the printing unit 10. But it also carries a frame 27 surrounding the window 26 which is slidably mounted on the top of the housing; the type of storage is clearly shown in Figure 2.

Another locking mechanism for the setting wheels 16 consists of a helical spring 66 which is arranged parallel to the longitudinal axis of the setting shaft 42 on the circumference of the setting wheels 16 so that it partially penetrates into the recesses 52 on the circumference of the setting wheels 16, which can be clearly seen in FIG. 2 is. So that the setting wheels 16 can be turned, although the screw spring 66 engages in its recesses according to FIG. 2, the helical spring is mounted on an elastically flexible cushion 68. When the adjusting wheels 16 are turned, the helical spring 66 can deflect in this way and press into the cushion 68.

The deflection wheels 18 are rotatably mounted on an axis 70 which extends parallel to the longitudinal axis of the adjusting shaft 42. Another locking mechanism 74 interacts with the deflection wheels and, in a manner known per se, locks the deflection wheel 18 in a position in which a printing type 22 is in the printing position.

The parts of the printing unit described so far are essentially known from the prior art, as described in EP 153651 A, which is incorporated by reference here.

It can be seen in FIG. 2 that a second printing unit 72, which is essentially the same as the printing unit shown on the left in FIG. 2, but has smaller printing types 22 ′, is also built into the housing 10.

In the printing unit shown on the left in FIG. 2, spacer elements 80 are provided which are adjustable between two positions. In the first position, the spacer elements identified by the reference symbol 80 'are pivoted vertically downwards. In this position, they do not engage between pressure tapes 20. In the second position, the spacer elements are identified with the reference symbol 80. They each lie between two adjacent pressure bands 20 and their tip is positioned between the setting wheels 18 over which the pressure bands 20 run. In the second position, the spacer elements 80 thus prevent adjacent pressure tapes 20 from touching, which considerably reduces the friction between them and enables the pressure tapes to be adjusted more easily with the actuating button 48. The first position is primarily provided for manufacturing reasons, since it allows the printing tapes 20 to be introduced into the housing of the printing unit 10 simultaneously, that is to say (directly next to one another in FIG. 1). The spacer elements are then moved from position 80 to the position 80 'by pivoting, in which they define the distance between adjacent pressure bands. Since the second printing unit 72 has significantly smaller printing types 22 'and thus thinner printing bands 20', the friction between the latter is lower, so that spacer elements can be dispensed with. The spacer elements 80 are arranged together on an axis 82 and are kept at a distance from one another by (cylindrical) spacer sleeves. As can be seen from FIG. 2, the axis 82 is provided with a square cross section, while the spacer elements 80 are equipped with a hole with two straight side surfaces, so that the spacer elements 80 are, as a result, fastened to the axis 82 in a form-locking and torque-locking manner. because the axis 82 through the hole extends. The spacer elements 80 are approximately rectangular and have the hole near one of the shorter sides. After the axis 82 with the spacer elements has been pivoted into the second position shown in FIG. 1, which is identified by the reference symbol 80, the axis 82 is locked in the housing, which is done in particular by screwing both ends of the axis to the housing.

According to the invention, the sleeve 28 and the locking finger 54 are designed as two separate elements that are separate from one another. FIG. 3 shows a view of the sleeve 28 with a locking finger 54 attached to it. The locking finger 54 is made of sheet metal and is shown individually in FIGS. 4 and 5. Its attachment in the sleeve 28 can be seen in Figure 6.

The latching finger 54 has a freely movable first section with a rounded head 60. The head 60 comes to rest in the recesses 56 of the adjusting shaft 42. The first section of the locking finger 54 is biased in this way, ie. bent in the assembled state of the printing unit with respect to the rest position shown in FIGS. 4 and 6, that the spring force necessary for locking in the recesses 56 is produced.

A second section 55 of the separate latching finger 54 is used to fix the latching finger 54 to the sleeve 28. For this purpose, on the side of the second section 55 facing the head 60, there is an extension which first extends in the direction of the longitudinal axis of the sleeve 28 and then in the direction of the head 60 to angled hook 58 and at the end of the second section 55, which faces away from the head 60, an extension 59 extending perpendicularly from the second section 55 in the direction of the longitudinal axis of the sleeve 28. The hook 58 and the extension 59 are made in one piece with the locking finger 54, and are formed in a press by a suitable deformation of the material of the locking finger 54. The locking finger 54 is preferably punched out of sheet metal.

The fixation of the locking finger 54 on the sleeve 28 can be seen clearly from FIG. 6. The hook 58 engages under a web of the sleeve 28, so that the web is clamped between the hook 58 and the second section of the locking finger 54. The extension 59 extends through a corresponding recess in the sleeve 28.

During assembly, the locking finger 54 is first placed on the sleeve in such a way that the hook 58 engages under the web. Then the locking finger 54 in its longitudinal direction, ie. in Figure 6 to the right, so far until the extension 59 is above the recess of the sleeve. Finally, the extension 59 is pressed into the recess. As a result, the locking finger 54 is thus attached to the sleeve 28 by a clip connection. Since the head 60 can only move in the vertical direction (with reference to FIG. 6) but not horizontally or perpendicular to the plane of the drawing in FIG. 6 when the adjusting shaft 42 is moved, it is adequately fixed.

The printing unit described is suitable for installation in hand-held labeling devices, with the aid of which self-adhesive labels adhering to a carrier tape can be printed and attached to objects. Such a hand-held labeling device is shown schematically in FIG. It has a handle 108 that is attached to the rear end of a housing 110. At the top of the housing 110 there is a shaft 112 which serves to hold a supply roll 114 of the carrier tape carrying the self-adhesive labels. The carrier tape is transported in the device from the supply roll 114 downwards and towards the front edge 115. It is guided over a printing table 118, at the front edge of which it is deflected at an acute angle so that the self-adhesive labels detach from the carrier tape and reach a position in which they can then be attached to objects. Such a device and its application are described for example in DE 3017843 A.

Underneath the handle 108 there is an operating lever 120 which is rotatably mounted about an axis 113 and with the aid of which all the processes taking place in the device, such as the transport of the carrier tape and the printing, can be carried out. To operate the device, the operating lever is pulled against the force of a spring 121 against the handle 108 and then released again. The printing unit 10 attached in the front area of the housing 110 to an extension of the operating lever 120 moves when the lever 120 is pulled in the direction of the arrow 122 against the printing table 118; At the same time, the printing types in the printing position are wetted with ink by means of a coloring device (not shown). The self-adhesive label located on the printing table 118 is printed on by opening the printing unit. As can be seen from FIG. 7, the actuating button 48 projects laterally on the housing 110, and a cutout 124 is provided in the housing side wall visible in FIG. 7, which enables the printing unit 10 to move in the direction of the arrow 122 without the printing unit pressing against the housing wall encounters.

Claims (10)

1. A printing device (10), having a casing; a setting shaft (42) axially displaceable in said casing, with recesses (56) spaced apart from one another in the axial direction of the setting shaft (42); a sleeve (28) encasing the setting shaft (42), the sleeve (28) being provided with a latch finger (54) capable of latching into one of the respective recesses (56) of the setting shaft (42) for definition of the axial position of the setting shaft (42), characterized in that the sleeve (28) and the latch finger (54) are provided as two parts.
2. The printing device according to claim 1, characterized in that a plurality of setting wheels (16) is coaxially rotatably mounted on the sleeve (28), said wheels being in driving contact with a type carrier, and the setting shaft (42) selectively cooperates with the setting wheels (16).
3. The printing device according to claim 1 or 2, characterized in that the latch finger (54) is made of metal.
4. The printing device according to any of the claims 1 to 3, characterized in that the sleeve (28) is made of plastic.
5. The printing device according to any of the claims 1 to 4, characterized in that the latch finger (54) is attached to the sleeve by a clip connection.
6. The printing device according to claim 5, characterized in that a hook (58) is formed on the latch finger (54) and that the hook 58 engages under a crosspiece of the sleeve (28) so that the crosspiece is clamped between the hook (58) and the latch finger (54).
7. The printing device according to claim 5 or 6, characterized in that an extension extending in the direction toward the longitudinal axis of the sleeve (28) is formed on the latch finger (54), which extension extends through a recess in the sleeve (28).
8. The printing device according to any of the preceding claims, characterized in that the latch finger (54) has a first section on which a rounded head (60) is present at the front end, the head being capable of latching into the recesses (56) of the setting shaft (42).
9. The printing device according to claim 8, characterized in that the first section of the latch finger (54) is so biased that the spring force required for latching into the recesses (56) is created.
10. The printing device according to any of the claims 6 to 9, characterized in that the latch finger (54) has a second section on which the hook (58) and/or the extension (59) are integrally formed.