EP0977095B1 - Printer with two printing units - Google Patents

Description

The invention relates to a printing or copying system, comprising a transport system for sheet-shaped recording medium.

Such electrophotographic printer are for example from the DE 34 16 252 A1 , of the EP 0 104 022 A2 , of the DE-PS 1,280,605 , of the DE 34 07 847 A1 or the WO 91/13386 known. With such printers, a high printing performance can also be achieved in duplex mode, as long as both printing units are working properly. A disadvantage of the devices described in the cited publications, however, is that in the event of failure of one of the printing units, they require a drastic reduction in the performance of the duplex operation. A sheet that is to be printed in duplex mode on both sides must then be accelerated several times in the opposite direction to be printed on both sides of the one remaining printing unit can.

From the US 5,150,167 a printing device is known which contains two printing units. One of the printing units has a priority status. Sheets that have been printed in the subordinate printing unit can be additionally printed in the priority printing unit. If, however, the priority printing unit fails, then no double printing and in particular no duplex printing is possible.

From the US 5,208,640 A Another printing device is known which contains a plurality of printing units. The printing units are connected to each other via a ring system, wherein a common turning device is used with a switch for all printing units. The printing device can operate in various modes such as simplex printing and duplex printing. document US-A-4,591,884 also describes a printing system that works with two printing units. Various modes of transport, including simplex printing and duplex printing, are possible with the help of various transport routes.

It is an object of the invention to provide a printing or copying system, which has a high printing performance or copy performance, especially in duplex mode.

This object is achieved by the features of claim 1. Advantageous embodiments of the invention are described in the remaining claims.

In the invention, a first printing unit and a substantially similar second printing unit is provided, to which sheet-shaped material can be supplied via a common input section. The sheet-shaped material printed by the second printing unit is output via a common output section. The two transfer printing transport paths of the two printing units are each connected via connection paths to two ring systems. At each of the two rings, a switch is provided, by the sheet-like material is independent of the respective other switch in the associated ring reversible.

In the apparatus according to the invention, two printing units are used. The components for these printing units, such as the electronic drive, the developer units, the toner supply and discharge devices, etc., can be maintained almost unchanged. Each printing unit on its own therefore has a very high operational reliability. Both printing works use a common one Input section, through which the sheet material is supplied. Likewise, both printing couples share an output section for discharging the printed sheet material. As a result, the new device is very compact and can be produced with little effort. Due to the two printing units, the printing performance is significantly increased.

By the Ringsysstem a printed from one of the two printing units, sheet-like material the same printing unit again in the same direction can be fed as in the first printing.

It is furthermore particularly advantageous if the two rings are connected via two three-way points. This creates a variety of transport routes.

Figur 1

schematisch den Aufbau eines Hochleistungsdruckers, bei dem die Erfindung verwirklicht ist,

Figur 2

schematisch die Betriebsart Simplexdruck mit dem unteren Druckwerk,

Figur 3

schematisch die Betriebsart Simplexdruck mit dem oberen Druckwerk,

Figur 4

die Betriebsart abwechselnder Simplexdruck,

Figur 5

die Betriebsart Duplexdruck,

Figur 6

die Betriebsart Zweifarben-Simplexdruck,

Figur 7

schematisch die Betriebsart Zweifarben-Duplexdruck, und

Figur 8

eine Anordnung mit zwei Hochleistungsdruckern, die durch eine Übergabevorrichtung miteinander verbunden sind.

Embodiments of the invention are explained below with reference to the drawing. It shows:

FIG. 1

schematically the construction of a high-performance printer, in which the invention is realized,

FIG. 2

schematically the operating mode simplex printing with the lower printing unit,

FIG. 3

schematically the operating mode simplex printing with the upper printing unit,

FIG. 4

the operating mode alternating simplex pressure,

FIG. 5

the operating mode duplex printing,

FIG. 6

the operating mode two-color simplex printing,

FIG. 7

schematically the operating mode two-color duplex printing, and

FIG. 8

an arrangement with two high-performance printers, which are interconnected by a transfer device.

In FIG. 1 there is shown a high performance printer 10 which is used to quickly print sheets of paper. The high-performance printer 10 includes a first, lower printing unit D1 and a second, upper printing unit D2. Both printing units D1, D2 work according to the known electrographic process with the same transfer printing speed. The printing units D1, D2 are followed by fixing, which schematically in the FIG. 1 are indicated by two pairs of rollers 12, 14. To the high-performance printer 10, a paper input 16 is connected, which contains a plurality of storage containers 18 to 24 with individual sheets and an external paper input channel 26, can be supplied from the outside of single sheets. About a transport channel sheets are fed to an input section 28. On the output side, a paper output 30 is connected to the high-performance printer 10, which contains a plurality of output containers 32 to 36. Furthermore, two output channels 38, 40 are provided, via which individual sheets can be output to further processing stations. The high-performance printer 10 delivers the printed single sheets over the discharge section 42.

Inside the high-performance printer 10 transport paths for the transport of the single sheets are arranged, are realized by the different modes of the high-performance printer. The printing units D1, D2 each Umdruck-transport paths 44, 46 are assigned, which are each set by drives so that the supplied single sheets on the printing units D1, D2 have their transfer printing speed. Both Transfer printing transport paths 44, 46 are connected to one another via a connecting channel 48. The transport path around the first printing unit D1 is supplemented to form a ring R1 by a feed channel 50, via which individual sheets can also be fed from the input section 28 to the second transfer printing path 46. The transport path for the second printing unit D2 is supplemented in a similar manner to form a ring R2 by a discharge channel 52, via which individual sheets printed by the printing unit D1 can be fed to the delivery section 42.

Between the input section 28, the first transfer transport path 44 and the feed channel 50, a first switch W1 is arranged, which allows individual sheets from the input section 28 optionally to the first transfer transport path 44 or the feed channel 50 are supplied. A further variant consists in that individual sheets transported on the feed channel 50 in the direction of the switch W1 can be fed to the first transfer printing transport path 44.

Furthermore, a second shunt W2 and a third shunt W3 are arranged at the ends of the connecting channel 48 and connect the adjacent transport paths 44, 48, 52 and 46, 48, 50, respectively. A fourth shunt W4 is located in the vicinity of the dispensing section 42 and connects the adjacent transport routes. The paper dispenser 30 includes a fifth shunt W5, which operates as a turning device. Furthermore, it should be noted on a Aussteuereinrichtung 54, which are supplied via a switch W6 Committee single sheets.

By the in FIG. 1 described arrangement, various modes of the high-performance printer 10 can be realized. In the following FIGS. 2 to 7 The different operating modes are shown schematically. The promotion of individual sheets is illustrated by arrows.

In FIG. 2 is schematically shown the simplex printing with only one printing unit. In this simplex printing, only one side of a single sheet is printed. The single sheet passes via the input section 28 and the correspondingly connected switch W1 along the arrow P1 to the first transfer printing path 44 and is printed on the printing unit D1. Subsequently, the cut sheet is discharged along the discharge passage 52 (arrow P2) via the discharge section 42 into the paper exit 30 (arrow P3).

FIG. 3 shows the simplex printing with the upper, second printing unit D2. The transport of the single sheet is via the feed channel 50 (arrow P4), the second transfer printing path (arrow P5) to the paper output 30 (arrow P6).

In the case of alternating simplex printing with increased printing capacity, individual sheets with at least twice the transfer printing speed of the printing couples D1, D2 are fed via the input section 28. FIG. 4 schematically shows the transport of the individual sheets. The switch W1 alternately feeds the feed channel 50 and the first transfer printing path 44 (arrows P7, P8). The individual sheets are braked on their transport up to the printing units D1, D2 on transfer printing speed, printed there on the front and then further promoted to the switch W4. In this further promotion according to the arrows P9, P10, the individual sheets are accelerated to at least twice the transfer printing speed, so that they are output at the common output section via the switch W4 with distance from each other and in the paper output 30 successively with at least twice the transfer printing speed according to the arrow P11 weiterertranspcrtiert can.

In the so-called "alternating simplex printing" mode, it is thus provided according to the invention that in the paper input 16 the individual sheets reach the input section 28 with at least twice the transfer printing speed of the printing units D1, D2 be supplied. Also in the paper output 30, the single sheets are also further promoted and stored at least twice the speed. As a result of these measures, the individual sheets arrive at the common input section 28 and at the common output section 42 without a collision of individual sheets and consequently a paper jam occurring. Preferably, the transport paths for the individual sheets fed to the first printing unit D1 and the single sheets fed to the second printing unit D2 are designed symmetrically or at least the same length, so that the single sheets with the same speed profile can be decelerated and accelerated on both transport paths. This makes it possible to build the same necessary for transport drives and devices. Furthermore, it is possible to use similar controls.

FIG. 5 schematically shows the duplex printing operation in which the single sheets are printed on both sides. The individual sheets fed to the input section 28 are supplied to the first transfer printing path 44 by the first switch W1 (arrow P13). After printing by the printing unit D1, the respective single sheet is conveyed a turning distance according to the arrow P14 on the switch W2. This turning distance is part of the Abführkanals 52. Subsequently, the conveying direction is reversed according to arrow P15, and the switch W2 then directs the cut sheet according to the arrow P16 in the connecting channel 48. The single sheet is then from the switch W3 in the direction of arrow P17 to the second Transfer printing 46 deflected. The printing unit D2 so the not yet printed back of the single sheet is fed for printing. Subsequently, the single sheets are fed according to the arrow P18 of the switch W4 and transported in the paper output 30 along the arrow P19. Since the single sheet is transported in this state with its rear side up, it is still to turn before storing in the compartments 32 to 36. The switch W5 is used for this purpose. The single sheet is first through the switch W5 in the direction of arrow P20 for a predetermined Turning course led. Then, the transport direction is reversed according to the arrow P21 and the switch W5 conveys the single sheet in the direction of the arrow P22, whereupon it is stored in the storage compartments 32 to 36 page correct.

As can be seen, the switch W2 works as a turning device to supply the printing unit D2, the back of the cut sheet. Alternatively, the turnout can also be used the switch W3. The individual sheet leaving the printing unit D1 is then guided via the shunt W2, the connecting channel 48 of the shunt W3 and then for a short turning distance along the feed channel 50 in the direction of the shunt W1. Subsequently, the transport direction is reversed and the switch W3 directs the single sheet in the direction of the printing unit D2 with its back upwards.

FIG. 6 schematically shows another mode, the two-color simplex printing, in which the front of a single sheet is printed with two image patterns of different colors. The two printing units D1, D2 print picture patterns of different colors. In the two-color simplex printing mode mentioned, the single sheet is fed to the printing unit D1 via the shunt W1 (arrow P25). Subsequently, the single sheet via the shunt W2 the connecting channel 48 without turning and then via the switch W3 the printing unit D2 supplied (arrows P26, P27). The printing unit D2 imprints the front side with a color different from the color of the printing unit D1. Subsequently, the single sheet is issued via the switch W4 to the paper output 30 (arrow P28).

FIG. 7 shows schematically the transport path of a single sheet in the operating mode two-color duplex printing, in which the front and the back of a single sheet are printed with image patterns of different colors. The prerequisite for this is that the printing units D1 and D2 print different-colored print images. For two-color printing on the front side as in the two-color simplex printing mode according to FIG. 6 proceed. The arrows P25, P26, P27 and P28 illustrate the transport route. Subsequently, the single sheet is fed again to the printing unit D1. The arrows P29 to P36 illustrate the transport path of the single sheet for printing the back. In order for this rear side to be fed to the printing unit D1, the single sheet must be turned on the transport path between the printing unit D2 and the printing unit D1. This turning can be done eg at the shunt W4, the shunt W2 or the shunt W3. In a preferred embodiment of the invention, turning takes place with the aid of the shunt W4, ie the single sheet is first transported for a short turning distance in the direction of the shunt W5, then the transport direction is reversed and the single sheet is conveyed further in the direction of the shunt W2. After transport into the paper output 30 according to the arrow P36, a further turning takes place through the switch W5 and then the correct side position of the double-sided printed with two color images single sheet.

Alternative transport of the cut sheet by the high-performance printer 10 for realizing the two-color duplex printing mode can be performed in the following manner. First, the single sheet is fed from the input section 28 via the switch W1 the printing unit D1, printed on its front side and then passed over the switches W2 and W3 for turning briefly in the direction of the switch W1. After passing the switch W3, the transport direction is changed in the direction of printing unit D2 and conveyed the single sheet on the transfer printing path 46. The turnout W3 thus serves as a turning station. At the printing unit D2 therefore the back of the single sheet is printed. Thereafter, the sheet is re-supplied via the switches W4, W2, W3 and W1 the first printing unit D1, to now print the back. The single sheet must be turned to this. This is done at switch W4, where it promotes short in the direction of switch W5, the transport direction is reversed and transported in the direction of switch W2 in the reversed state. After printing on the back of the single sheet in the printing unit D1, the single sheet is fed via the switches W2 and W3 the printing unit D2, wherein it is turned. Now the front side of the printing unit D2 is printed. Subsequently, the single sheet is guided via the switch W4 to the storage compartments 32 to 36. Since it now passes in the correct position, ie with the top side up in the tray 30, it does not have to be turned again by the switch W5.

FIG. 8 shows the arrangement of two high-performance printer 10 and 10 'to a printing system 55. The two high-performance printers 10 and 10' are of similar construction, the individual components must therefore not be explained again. Arranged between the output channel 38 of the first high-performance printer 10 and the external paper input channel 26 of the second high-performance printer 10 'is a transfer device 56 which conveys single sheets from the high-performance printer 10 to the high-performance printer 10'. Each high performance printer 10, 10 'can implement the previously described simplex, alternate simplex, two color simplex, one color duplex, and two color duplex modes. By combining the various modes of operation in which a first mode is set in high performance printer 10 and a matching or other mode in high performance printer 10 ', new variants of modes may be realized. For example, both high-performance printers can operate in two-color simplex mode, the first printer printing the front side with two differently colored image patterns and the high-performance printer 10 'printing the back side with two differently colored image patterns. If in each case different colors are selected for a total of four different printing units, four-color duplexing can be realized by the printing system 55, ie in each case the front side and the back side can be printed with four differently colored image patterns.

The printing system 55 can be further extended by connecting at least one further high-performance printer in the manner of the high-performance printer 10 to the high-performance printer 10 '. In this way, utilizing all the technical capabilities of high performance printers, n-color duplex printing can be achieved by printing on the front and back of a single sheet a n image pattern with n different colors, where n is any integer.

Claims (9)

1. Printing or copying system, comprising a transport system for sheet-type recording media, comprising:

   - a first shunt (W1) which is configured such that via the first shunt sheet-type recording material can be alternatively supplied to a transfer printing transport path (44) of a first printing unit (D1) or via a supply channel (50) to the transfer printing transport path (46) of a second printing unit (D2),

   - a second shunt (W2) which is configured such that via the second shunt sheet-type recording material which has been printed by the first printing unit (D1) can be alternatively supplied via a carrying-off channel (52) to an output section (42) or to a connecting channel (48),

   - a third shunt (W3) provided on the connecting channel (48) and configured such that via the third shunt sheet-type recording material coming from the connecting channel (48) can be alternatively supplied to the transfer-printing transport path (46) of the second printing unit (D2) or the supply channel (50), and

   - a fourth shunt (W4) which is configured such that it supplies sheet-type material both coming from the transfer printing transport path (46) of the second printing unit (D2) as well as coming from the carrying-off channel (52) to the output section (42).
2. Printing or copying system according to claim 1, in which at least one of the shunts (W2, W3, W4) is designed as a turnover device.
3. Printing or copying system according to claim 1 or 2 wherein the recording material can be transported in the supply channel (50) in two opposite directions (P7, P31).
4. Printing or copying system according to one of the claims 1 to 3, wherein the recording material can be transported in the carrying-off channel (52) in two opposite directions (P10, P29).
5. Printing or copying system according to one of the claims 1 to 4, wherein via the supply channel (50) and/or via the connecting channel (48) recording material which has been printed on the front by the first printing unit (D1) can be supplied to the first printing unit (D1) for re-printing on the back.
6. Printing or copying system according to one of the claims 1 to 5, wherein via the carrying-off channel (52) and/or via the connecting channel (48) recording material which has been printed on the front by the second printing unit (D2) can be supplied to the second printing unit (D2) for re-printing on the back.
7. Printing or copying system according to one of the claims 1 to 6, wherein the system is configured such that the recording material can be printed by the first printing unit (D1) with a first colour and by the second printing unit (D2) with a second colour.
8. Printing or copying system according to one of the claims 1 to 7, wherein the supply channel (50) runs substantially parallel to the transfer printing transport path (44) of the first printing unit (D1).
9. Printing or copying system according to one of the claims 1 to 8, wherein the carrying-off channel (52) runs substantially parallel to the transfer printing transport path (46) of the second printing unit (D2).

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