DE19510728C1 - Recording web storage device for electrographic printer - Google Patents

Abstract

The storage device is provided between a transport drive (3) for feeding a pair of parallel recording webs (4,5) through a printing station (2) and a friction drive (8/1,8/2) for transporting the webs through a fixing station. The device is provided by a web loop obtained via a deflection element (25) acting on each of the webs, which is pivoted about an axis under control of a deflection spring (13), coupled to a tensioning device (32)for adjusting the spring tension.

Description

The invention relates to a device for precise position Synchronize the parallel run of the record carrier NEN in an electrographic printing device in which two Record carrier webs via a drive device operated a transfer printing station in parallel, side by side run through and then parallel via a tape storage each other a fuser with a friction drive leads.

An electrographic printing device with two in parallel arranged record carrier webs simultaneously by the Printer is moved and printed, for example, is off the where known 94/27193. With such printing devices and other paper processing plants, where two pa parallel paper webs successive functional units run through with friction or positive drive, is of particular problems in driving the paper webs. So To avoid malfunctions, a parallel syn ensure chronic paper flow.

To different transport speeds different Compensate aggregates of a printer or copier it is known from DE-C1-42 35 704, egg between the units to arrange a length buffer in the form of a loop puller.

It is also an electrophotography from EP-A2-0572 050 fish printing device with a fuser from a be heated fuser roller and a pressure roller known Speed depending on the deflection of one as a buffer Storage loop puller is regulated so that the  Record carrier exactly free of relative movement between Fi xierwalze and pressure roller is moved.

In the known units it was assumed that be The slightest relative movements of record carriers and Fixing roller may blur the printed image.

The object of the invention is a simply designed Device for precise synchronization of the Paral Run of record carrier webs in an electrograph to provide pressure device at the two on Drawing carrier webs via a drive device operated a transfer printing station in parallel, side by side run through and then parallel via a tape storage each other a fuser with a friction drive leads.

This task is at the beginning of a tape storage ge named type solved according to the features of claim 1.

Advantageous embodiments are in the subclaims featured.

Pass through the paper webs in parallel and synchronously with each other following drives, such as the form-fitting transport facility in the transfer station and the friction drive in the fuser, are formed by running differences in the Paper webs of different sizes, which are separated by egg ne synchronization control device must be compensated sen. For this purpose, the arrangement of a buffer memory is between necessary for the drives that buffer the individual tracks and  its memory content via the synchronization control device is detected. The synchronization rule Depending on this, direction controls the slip in the frame tion drive of the fuser, for example via a pre switched on paper brake or by changing the contact pressure pressure between the fixing roller and the pressure roller and thus regulates the synchronization of the record carrier webs.

Such a regulation on the slip is particularly in the use of a friction drive in a fuser unusual, as a slip usually blurs the Toner image results in what should be avoided.

It has proven to be an important factor influencing synchronization the influence of the tape storage also continues the tension forces on the webs highlighted.

The tape storage enables targeted reproducible Introduction of tension forces on the individual paper webs. It is easy to use and not susceptible to faults. Depending speed of the operating mode of the printing device, it is easy modifiable. Forces, force relationships or force characteristics can be easily adapted to the desired course.

Embodiments of the invention are in the drawings are shown and are based on the drawings described in more detail by way of example. Show it

Fig. 1 NEN a schematic representation of the paper feed in a printing device with duplex printing on a single paper web having two parallel-running Aufzeichnungsträgerbah,

Fig. 2 is a schematic representation of the structure of a printing device with duplex printing corresponding to FIG. 1 with a control device for synchronization of the parallel and parallel recording medium webs

Fig. 3 to 7 are schematic representations of loop puller configurations with adjustable deflection force and under different force characteristics.

The invention is based on the structure of a electrographic printing device for one or both sides Printing on a tape-shaped recording medium described ben.

According to the illustration of FIG. 1, in the printing device to the invention OF INVENTION the tape-shaped recording starting from a feed area, for carrier 1. B. drawn from a roll in the printer and be printed in the alignment line 2 with the front associated toner images. The record carrier 1 is designed as a pre-folded continuous paper with a predetermined form length. In the area of the alignment line 2 is the transfer printing area for transfer printing of the toner images from an intermediate carrier (photoconductor drum) onto the recording medium 1 with a structure corresponding to WO 94/27193. The drive 3 in the order pressure area takes place positively via tractors with nipples arranged thereon, which engage in corresponding edge perforations (shown as white omissions) of the recording medium 1 . To distinguish the freshly drawn web assigned to the front from the returned and turned web assigned to the rear in the transfer printing area (alignment line 2 ), consider the "front web" A web (reference number 5 ) and the "back web" B web (reference 4 ) called. The A web 5 passes a band memory in the form of a loop tensioner 6 and is driven by a negative pressure brake 7 by a friction drive 8 in the form of a fuser. Thereafter, the web 5 is fed back, turned in a turning device 10 and in the form of the parallel to the freshly drawn web 5 again fed to the positive drive ( 3 ) as a B-web ( 4 ). Here, when passing alignment line 2, the reverse side is printed in the transfer area parallel and synchronous to A-Bahn 5 . Next runs the B-Bahn 4 parallel to the A-Bahn 5 via the loop puller 6 , the vacuum brake 7 and again by the friction drive 8 of the fixing station. Then it is a paper edition z. B. a stacker or other Papiernachver processing device supplied.

Between the return of the A-web 5 and the re-feeding of the web 5 into the positive drive 3 as the B-web 4 , a tape store 11 in the form of a loop puller is arranged behind the turning device 10 in the paper transport direction. In the arrangement described here, this loop corresponds to the web store between two form-fitting drives. The memory content of the loop therefore does not change summarily even without regulation. The memory is only necessary to compensate for tolerances and for form synchronization when inserting forms of different lengths.

The friction drive 8 is formed in the printer from the fixing roller 8/1 and the pressure roller 8/2 and has the task of fixing the toner images on the recording medium 1 . The driven fuser roller 8/1 is therefore heated. The moving pressure roller 8/2 is pressed against the fixing roller 8/1 . In the fixing gap 9 between the two rollers, the paper web is pressed, heated and driven. The web shrinks due to moisture loss in the longitudinal and transverse directions. This means that the distances between the form elements (forms, perforation holes) decrease. It follows that after the return, the B-Bahn 4 runs at a lower Bahnge speed from the positive drive 3 than the A-Bahn 5th

Control elements

The control device for precise synchronization of the parallel operation of the recording medium webs 4 , 5 can be divided into the following assemblies according to the illustration in FIG. 2.

Loop puller assembly

It consists of the loop puller unit 6 from two of the respective web 4 and 5 associated loop pullers 6/1 , 6/2 , each of which has a loop puller angle sensor 12 , a spring mechanism 13 for the loop puller 6 and an adjustment device 14 for the loop puller torque ment. A device for coupling the two loop pullers 6/1 , 6/2 is not shown.

Vacuum brake functional area

It consists of a device for generating negative pressure 15 z. B. a suction pump, which is connected to a vacuum valve and control assembly 16 from two separately controllable valves 16/1 , 16/2 and coupled to the actual vacuum brake 7 from two separate sliding surfaces 7/1 , 7/2 with suction holes is.

Fixing area

It consists of the fixing roller 8/1 , a drive 17 in the form of an electric motor for the fixing roller 8/1 , the pressure roller 8/2 and a pivot mechanism 18 for the pressure roller 8/2 from two coupled via an axis of rotation with a drive 19 Cams that engage the axis of the pressure roller 8/2 via lever elements.

electronics

This includes the actual control electronics 20 from a microprocessor-controlled arrangement constructed in the usual way, which uses bus lines with a power electronics 21 for the drive 17 of the fixing station, the drive 19 of the pressure roller and the valves 16/1 , 16/2 of the brake 7 in connection stands and is connected via a bus line with a control electronics 22 constructed in the usual way for a drive 23 of the positive drive 3 (caterpillars) of the order printing station. The control electronics 20 is further coupled via lines to the rotation angle sensors 12 of the smart fie 6 and is connected via a bus line 24 with the device control of the printer. Their structure is known from WO 94/27193.

Input variables for the control are fed via the bus or control lines 24 from the environment (device control) and via the control 22 from the drive 23 to the transport caterpillars in the transfer printing station of the control electronics 20 .

Function of the control device

Through collective and web-specific regulation, the size of the slip occurring of each individual paper web 4 , 5 in the friction drive 8 is regulated so that a trouble-free Pa pierlauf is guaranteed.

For this purpose, the regulation during and outside the Druckbe influence drive:

• - the speed of the friction drive,
• - the paper tension forces of the individual paper webs,
• - the surface pressure in the nip of the friction drive,
• - The coefficient of friction of the friction roller (via its oiling).

It also serves to:

• - Control processes during paper loading, start and Stop.
• - Detection of machine and paper run errors.

Between the positive operation 3 and the friction drive 8 each track has the web storage, which is also referred to as a tape store. Herein a loop puller 6/1 , 6/2 tensions the paper web 4 , 5 and measures the content of the web storage (the length of the paper loop).

The regulation is divided into two largely independent from each other dependent function groups:

The loop length control

The loop length control acts in the same direction on both paper loops 4 , 5 . The main instrument of this regulation is the speed of the friction roller (fixing roller 8/1 ).

The loop difference control

The loop difference control acts in opposite directions on both paper loops 4 , 5 . The main instrument here is the web-specific regulation of the tension in the respective paper web.

The basic procedure of the regulation is to keep the paper loop length, that is to say the storage content of the tape store 6/1 , 6/2, within permissible limits.

Such a regulation on the slip is particularly in the use of a friction drive in a fuser unusual because a slip is usually a blurring of the Toner image results in what should be avoided.

Different embodiments of the loop puller

Depending on the desired different function options of the control device, various embodiments of the claw extractor shown in FIGS . 3-7 can be used:

Basic structure ( Fig. 3)

The adjacent loop pullers 6/1 , 6/2 are each deflected with their own spring 13/1 , 13/2 , which act on articulation lever 30 on articulation elements 25 .

The initial angular position of the deflection elements 25 influences the change in the return torque (M) of the loop puller with the loop puller angle (β). On the other hand, the respective spring 13/1 , 13/2 is connected with a rope 31 . This rope 31 is attached to a retractor 32 . Here, a shaft 35 is rotated via a hand crank 33 and a worm gear 34 . The Aufrollvor direction 32 can work spinning or only in a defined angular range. The two rope pulleys 36/1 , 36/2 and a pointer 37 of a force setting scale 38 sit on this shaft 35 .

Due to the special design of the retractor 32 , the return torque between the two loop pullers 6/1 , 6/2 can be adjusted.

Symmetrical execution

In a symmetrical embodiment according to FIG. 4, the generated back torques M of the two loop pullers 6/1 , 6/2 are the same in both tracks A, B. This is advantageous if the paper webs have the same structure and there is no tendency that one web generally tends to have a larger loop than the other. The characteristic curves shown next (abscissa β, ordinate M) of the reverse torques M are the same in each of the adjustment positions (I, II of the scale) for both loop pullers 6/1 , 6/2 .

Instead of the rope pulleys 36/1 , 36/2 , link levers can also be used.

Unsymmetrical designs

Unsymmetrical designs are advantageous if the Behaviors with predictable directions behave differently. Here you can use different, forces and force characteristics be held up.

Provision of a page

If the rope 31 ( Fig. 3) is shortened only on a loop puller, there is a difference between the two moment characteristics. With an otherwise symmetrical roll-up behavior, this difference remains the same across all force settings. In asymmetrical arrangements, the rope length creates a specific offset between the loop pullers of the A and B lanes.

Different roll-up behavior

Different diameters of the rope pulleys ( Fig. 5) With this arrangement it is achieved that a difference between the two torque characteristics changes linearly over the adjustment. The special case is shown that the two characteristic curves coincide in the adjustment position I. If the adjustment does not turn, this effect can also be achieved with differently long control levers.

Other forms of roll-up curves ( Fig. 6, 7)

Should the adjustment of the difference (s) between others can change the torque characteristics nonlinearly Roll-up curves are used. These are generally different Curve shapes with the special cases: eccentric, ellipse, spi rale.

Lever linkages ( Fig. 6, A-side)

Instead of the rope pulleys 36 , levers 39 can also be used, on which the rope 31 is articulated. With different lead angles it is possible to achieve different and non-linear adjustment characteristics.

Different spring characteristics ( Fig. 7)

Due to different spring rates of the springs 13/1 , 13/2 , the slopes of the torque characteristics are designed differently. The difference in the slope of the characteristic remains the same across different force settings. Springs with different preload act like changing the rope length between the A and B sides.

Combinations

There are also combinations of the versions shown possible. So from the previously described adjustment Direction deviates from the adjustment of the two loops characteristics also used two adjustment devices will.

With separate adjustment devices for the loop puller 6 , these can be adjusted independently of one another.

With a composite adjustment device from two z. B. summary acting devices can on the one hand adjust the force level of the two sides in the same direction, on the other hand the force difference between the two cunning fenziehern 6th

Motorized adjustment

The mechanical adjustment explained here via crank 33 and worm gear 34 can also take place automatically (e.g. with an electric motor). This also applies to the separate adjustment.

The printer can determine the setpoints for the automatic adjustment of the loop pulling forces. The loop puller forces can be set once when loading the paper or additionally dynamically during operation. Relevant measured variables are: paper width, position of the loop puller 6 , position of the web edge after the loop puller 6 and the slippage of the webs 4/5 in the subsequent fixing station 8 .

The paper webs are driven by positive locking at the described embodiments about paper transport beads or pin wheels that are in transport holes in the paper intervention. There is also a positive drive here Drive meant that the mechanics according to a friction is driven, but by z. B. electronic means on the Transport of shaped elements is regulated. Such an approach drive therefore regulates different slip automatically and behaves like in relation to the web speed a form-fitting, drive. Form elements are recurring detectable features associated with the paper web. This can be, for example: transport perforations, printing marks, Folds, perforations, labels.

Reference list

1 record carrier
2 Alignment line in the transfer station, transfer station
3 positive drive, tractors
4 B-Bahn rear panel
5 A-Bahn front panel
6, 6/1, 6/2 loop puller
7, 7/1, 7/2 vacuum brake
8 friction drive
8/1 fuser roller
8/2 pressure roller
9 fixing gap
10 turning device
11 tape storage in the B-Bahn after the turning device
12 rotation angle sensor
13 spring mechanism in the loop puller unit
13/1, 13/2 springs
14 Adjustment device for the loop puller unit
15 Device for generating negative pressure
16 vacuum valve and control assembly
16/1, 16/2 separately adjustable vacuum valves
17 Drive of the fixation station
18 Swing mechanism for pressure roller
19 Drive for swivel mechanism
20 control electronics, control unit
21 power electronics
22 Control electronics
23 Crawler drive, electric motor
24 bus line
25 Looper pull lever
30 link lever on the loop puller
31 rope
32 retractor
33 hand crank
34 worm gear
35 wave
36, 36/1, 36/2 pulleys
37 hands
38 force setting scale
39 levers
M Loosening torque of the loop puller
β deflection angle
I lower deflection range
II upper deflection area

Claims (9)

1. Device for accurately synchronizing the parallel run of record carrier webs ( 4 , 5 ) of an electrographic printing device, in which two recording carrier webs ( 4 , 5 ) via a drive device ( 3 ) are driven through a transfer station ( 2 ) in parallel synchronously next to each other and then in parallel via a tape storage device next to each other a fixing station ( 8 ) with a friction drive ( 8/1 , 8/2 ) are fed and the tape storage device is assigned to the record carrier webs ( 4 , 5 ), respectively, loop puller ( 6/1 , 6/2 ) has a on the recording carrier webs ( 4 , 5 ) engaging ver about an axis of rotation pivotable deflection element ( 25 ) with associated deflection spring ( 13 ), the deflection spring ( 13 ) with a clamping device ( 32 ) for adjusting the spring preload pelt, and one of which runs in parallel by controlling the slip of the friction drive ( 8/1 , 8/2 ) relative to the Au Drawing carrier webs ( 4 , 5 ) as a function of the filling condition of the tape store ( 6/1 , 6/2 ) synchronizing control device ( 20 ) is provided. 2. Device according to claim 1, in which the tensioning device ( 32 ) has an axis of rotation ( 35 ) which can be rotated via an adjusting device ( 33 , 34 ), on which one or more pulling means ( 31 ) on the one or more deflection springs ( 13/1 , 13/2 ) are arranged on gripping actuating elements ( 39 , 36 ). 3. Device according to claim 2, in which the actuating elements ( 36 ) are designed as sheaves ( 36/1 , 36/2 ) for receiving the train means ( 31 ) with a rollup curve adapted to the intended torque curve (M) for the train tel ( 31 ). 4. Device according to claim 2, wherein the actuation supply elements ( 36 ) as a link lever ( 39 ) for receiving the train means ( 31 ) are formed with a length adapted to the intended torque curve. 5. Device according to one of claims 2 to 4, wherein said adjusting means (33, 34) with an adjusting position of the adjusting means (33, 34) indicating means (37, 38) is coupled. 6. Device according to one of claims 1 to 5, in which the loop puller ( 6/1 , 6/2 ) are designed such that the tensioning force is introduced symmetrically into both recording medium webs ( 4 , 5 ). 7. Device according to one of claims 1 to 5, in which the loop puller ( 6/1 , 6/2 ) are designed such that the clamping force is introduced asymmetrically in both record carrier webs ( 4 , 5 ). 8. Device according to one of claims 1 to 7, with a motor-operated clamping device ( 32 ). 9. Device according to one of claims 1 to 8, with a the deflection position of the loop puller ( 6/1 , 6/2 ) scan the sensor device ( 12 ).