DE9408360U1 - Printer with simple transport and storage mechanism for double-sided, full-page printing of single sheets - Google Patents

Description

Utility model application reference number: G 94 08 360.6

Applicant: GeBE Elektronik und Feinwerktechnik GmbH Beethovenstraße 15, 82110 Germering

Printer with simple transport and storage mechanism for double-sided, full-page printing of single sheets.

Overview

The small office printers on the market for printing single sheets either work with a platen roller similar to the traditional arrangement of a typewriter or they guide the paper past a printing bar using transport rollers.

Matrix print heads are primarily used as writing elements today. Matrix print heads allow letters, shapes and even images to be created in any shape by arranging the points in the print matrix, including upside-down letters or in mirror writing, without having to change the hardware of the mechanism. In this way, it is possible to print a page upside down, starting with the bottom line, and thus to print a single sheet on both sides with just one print head, without the sheet having to be laboriously turned over in such a way that, before printing on the back, the sheet is turned over to the back and then rotated by 180°, as is necessary with manual operation, for example with a typewriter. In contrast to the method described here, very complicated and complex constructions have been described that use conveyor belts and paper switches to turn the sheet printed on the front and return it to the printer's input. In contrast, in the simple, inexpensive device described here, the single sheet already printed on the front is stored in a single sheet storage unit and returned together with this to the printer input.

Single-sided printing

In working position 2, a single sheet can be fed into the printer from the outside, which is then only printed on the front and then immediately ejected. This saves time if the single sheet is only printed on one side.

Full, full-page printing

Another significant advantage of the arrangement described as an example is that the front and back of the single sheet can be completely printed up to the top and bottom edges of the paper by the transport rollers of the paper storage arranged directly behind the print head in the paper transport direction.

Cost-effective paper transport

By using the friction wheel between the printing roller and the transport rollers of the paper storage, the paper transport is carried out cost-effectively with only one drive motor on the printing roller. This is the main idea behind this invention, namely that in the two working positions 1 and 2, the desired synchronous paper transport through the transport rollers and the printing roller takes place in the right directions without any additional drive elements due to the clever arrangement of the friction wheel.

Embodiments (examples)

Fig. 1a and 1b show an example embodiment of the invention on a printer. Here, in working position 1 (Fig. 1a), side A (1) is printed. The single sheet (2) is transported into the single sheet storage (3) by the outer roller (10) of the storage transport roller pair (5), which rotates clockwise by force-locking transmission of the direction of rotation of the printing roller (4) by means of the interposed friction wheel (11). If the sheet (1) is completely in this single sheet storage unit (3), it is moved from the working position (Fig. 1a) to the working position (Fig. 1b) via the pivot lever (12), so that now, with the same direction of rotation of the printing roller (4) as the inner roller (13) of the storage transport roller pair (5), which now also rotates clockwise, the single sheet (2) is fed back into the feed slot (6) of the printer. Now side B (7) of the single sheet (2) is printed by the print head (8) and the single sheet (2) is ejected from the printer using the ejection transport rollers (9).

The storage mechanism is supported by pivoting levers (12) arranged in a parallelogram. In order to achieve a good frictional connection between the friction wheel (11) and the inner transport roller (3) and the outer transport roller (10) of the transport roller pair (5), these are spring-mounted so that they swing in the longitudinal or transverse direction, so that optimal self-adjustment takes place when the transport rollers sit on the friction wheel (11). A separate motor drive or a direction-dependent switching mechanism that is also driven by the drive motor of the pressure roller (4) is used to move the entire storage mechanism from the working position 1 (Fig. 1a) to the working position 2 (Fig. 1b).

Fig. 2a and 2b show another example embodiment in which the storage mechanism is fixed via guide rods (14) so that the movements from the working position 1 (Fig. 2a) to the working position 2 (Fig. 2b) and back are limited by an adjustable stop (15) so that the storage transport rollers (5) and the ejection transport rollers (9) are self-adjusting and sit securely on the friction wheel (11) with a force fit. The entire storage mechanism is driven and the front guide is carried out by a separate motor drive via the pivot lever (16). The single-sheet storage (3) is spiral-shaped.

Claims (4)

Protection claims 1. Printer with simple transport and storage mechanism for double-sided, full-page printing of single sheets, characterized in that • a friction wheel is driven together with the pressure roller, • above the friction wheel, a pair of storage transport rollers (5) that can be swiveled back and forth between the front (working position 1: Fig. 1a) and the back (working position 2: Fig. ib) of the printing roller and that are positioned against each other is arranged in such a way that in the working position the outer roller (10) and in the working position 2 the inner roller (13) are driven in contact with the friction wheel, synchronously with the printing roller, and so in the working position 1 a paper lying between the transport rollers is transported into the paper storage located behind the pair of transport rollers and in the working position 2 it is transported out of the paper storage, • in the paper storage the paper is arranged in a straight or curved or spiral shape, • a separate drive or the drive of the printing roller can swivel the storage transport roller pair together with the paper storage into both the working positioni and the working position2, • the axles of the transport rollers are mounted in elongated guides in a pendulum and spring-loaded manner, • a pair of ejection rollers on the Paper exit behind the print head rests against the friction wheel and is driven by it when the storage transport roller pair is pivoted into the paper insertion position (working position 2), • the storage transport roller pair, the ejection transport roller pair and the paper storage are attached to a frame that can be pivoted back and forth and are connected to one another (as a paper turning mechanism). 2. Printer according to claim 1, characterized in that the guidance of the paper turning mechanism is carried out by guide levers in the sense of a parallelogram guide. 3. Printer according to claim 1, characterized in that the paper turning mechanism is attached to guide rods in such a way that it can be pushed back and forth between positions 1 and 2, and that the exact position of position i, in which only the outer roller of the storage transport roller pair on the print head side of the printing roller rests on the friction wheel, is determined by a stop on the guide rods, while in position 2 both the storage transport roller pair and the ejection transport roller pair rest on the friction wheel. 4. Printer according to claims 1 to 3, characterized in that the transport of the turning mechanism is carried out via a switching mechanism dependent on the direction of rotation via the drive of the printing roller.