EP0505404A1

EP0505404A1 - Fixing station for an electrophotographic printer or copier.

Info

Publication number: EP0505404A1
Application number: EP91900252A
Authority: EP
Inventors: Karl Heigl
Original assignee: Wincor Nixdorf International GmbH
Current assignee: Canon Production Printing Germany GmbH and Co KG
Priority date: 1989-12-13
Filing date: 1990-11-27
Publication date: 1992-09-30
Anticipated expiration: 2010-11-27
Also published as: EP0505404B1; US5301000A; DE59005966D1; JPH05504633A; WO1991009351A1

Abstract

Dans la station de fixage d'une imprimante ou d'un copieur électrophotographiques sont disposés un cylindre de fixage (11) chauffé par un module radiateur (30), et un cylindre de pression qui pivote en direction et à l'opposé du cylindre de fixage (11) par l'intermédiaire d'un mécanisme à cames (8, 7). Afin que le cylindre de fixage et le cylindre de pression puissent être remplacés tout en étant encore chauds, le cylindre de fixage (11) est monté dans des brides de palier (14, 16), dont l'une (16) est fixée à demeure dans l'appareil tandis que l'autre (14) est montée amovible. La bride amovible (14) comporte des éléments de serrage (26) qui maintiennent le cylindre de fixage, ainsi qu'une poignée au moyen de laquelle la bride (14), avec le cylindre de fixage (11) qui y est rattaché, peut être enlevée de la station de fixage. Le cylindre de pression (9) est monté amovible entre deux coulisses (8) par l'intermédiaire d'un boulon de fixation amovible (57). Un dégagement de refroidissement (40, 51) destiné à recevoir le cylindre de fixage (11) chaud et le module radiateur (30) est également ménagé dans l'appareil.In the fixing station of an electrophotographic printer or copier are arranged a fixing cylinder (11) heated by a radiator module (30), and a pressure cylinder which pivots towards and away from the cylinder of fixing (11) by means of a cam mechanism (8, 7). So that the fixing cylinder and the pressure cylinder can be replaced while still hot, the fixing cylinder (11) is mounted in bearing flanges (14, 16), one of which (16) is fixed to remains in the device while the other (14) is removably mounted. The removable flange (14) has clamping elements (26) which hold the fixing cylinder, as well as a handle by means of which the flange (14), with the fixing cylinder (11) attached to it, can be removed from the fixing station. The pressure cylinder (9) is removably mounted between two slides (8) by means of a removable fixing bolt (57). A cooling space (40, 51) for receiving the hot fixing cylinder (11) and the radiator module (30) is also provided in the device.

Description

Fixing station for an electrophotographic printing or copying device.

In electrophotographic printing or copying devices, it is customary to fix the recording medium coated with toner in a thermal fixing station. Such thermal fixing stations generally contain electrically heated fixing rollers with associated pressure rollers that can be pivoted on and off. The recording medium is passed between fixing rollers and pressure rollers for fixing. The toner is fixed on the recording medium by the action of heat from the fixing roller. As the tonner during the short contact distance of the record carrier with the fixing roller

Melting temperature must be brought, a high heating output on the part of the fixing roller is necessary. For this purpose, it is common to install halogen lamps with high heating power in the hollow fixing roller.

However, halogen spotlights have the disadvantage that their burning time is relatively short and therefore it is necessary to replace them frequently.

In the past, it was customary to have the defective radiant heater and the defective fuser roller replaced by a trained maintenance technician when the device was cold. This leads to a long downtime and high expenses for the repair of the device. A particular disadvantage was that, before the actual replacement, it was necessary to wait until both the fixing roller and the halogen radiator to be replaced cooled, because of the high heat capacity of the fixing roller, this can take a long time.

To replace the radiant heater, it was also necessary to remove the entire heating roller, which made the replacement additional complicated.

Since the record carrier is moved between the fixing roller and the pressure roller by friction, the pressure roller is subject to relatively high wear. To replace the pressure roller, it was previously common to disassemble the entire fusing station. This is complex and leads to longer undesired downtimes of the printing device. The object of the invention is to design a fixing station of the type mentioned at the outset in such a way that it is constructed to be maintenance-friendly, so that wearing parts can be replaced without special tools. This object is achieved in a device of the type mentioned at the outset according to the features of the first claim.

Advantageous embodiments of the invention are characterized in the subclaims.

According to the invention, both the fixing roller and the pressure roller can be exchanged without special tools. The heater module arranged in the fixing roller for heating the fixing roller is also designed to be exchangeable, the fixing roller being able to remain in the fixing station in order to replace this particularly wear-prone part. In order to be able to cool down the hot rollers that have been replaced or the heater module, the device has a cooling rack. The downtimes required for the maintenance of the device are considerably shortened by the invention. The exchange can be carried out by the operator of the device himself, without the need for specially trained maintenance technicians. An embodiment of the invention is shown in the drawings and is described in more detail below, for example. FIG. 1 shows a sectional illustration of a fixing station in an electrophotographic printing device

Figure 2 is a sectional view of a heating roller in a fixing station of an electrophotographic printing device with a radiator module arranged therein

Figure 3 is a schematic representation of an electrophotographic printing device with the front panel removed when the radiator module is replaced

FIG. 4 shows a schematic illustration of an electrophotographic printing device with the front plate removed when the fixing roller is replaced. FIG. 5 shows a schematic illustration of the mounting of the pressure roller in a top view

FIG. 6 shows a schematic sectional illustration of the drive of the pressure roller in a top view corresponding to FIG. 5

Figure 7 is a schematic representation of the adjustment mechanism for the pressure spring force of the pressure roller and

Figure 8 is a schematic representation of the pressure roller exchange.

A fixing station (FIG. 1) of an electrophotographic printing device contains a fixing roller or heating roller 11, which is mounted on a frame 10 of the printing device, and a pressure roller 9 made of a steel tube covered with rubber. The pressure roller 9 is mounted on two rockers 8 and can be operated with the aid of 2 electromechanically driven cam disks 7 can be pivoted onto and off the fixing roller 11 via the lugs 6 (arrow direction). The rockers 8 are pivoted about the axis 4 against the force of springs 5. The heating roller 11 consists of an aluminum tube 13 coated with Teflon 12, which is open on both sides. The heating roller 11 is mounted in the frame 10 of the fixing station, namely on one side via a bearing flange 14 with a central holding and guiding opening 15 and on the other side via a bearing element 16, which is shown in FIG Form of a pulley 18 is connected. A bearing 19/1 is located on the bearing flange 14 and engages with a centering piece 20 in the aluminum tube 13 of the heating roller 11. The other bearing element 16 with bearing 19/2 on the drive side of the fixing station also has a centering projection 21 which engages in the other side of the aluminum tube 13 of the heating roller 11. In order to be able to store the heating roller 11 securely, plate springs 22 are arranged on the bearing element 16, which engage the heating roller via a disk 22/1 and press against the centering piece 20 of the bearing flange 14. They ensure the compensation of the axial thermal expansion. The aluminum tube of the heating roller 11 slides on the centering shoulder 21, the disc 22/1 being connected to the centering shoulder 21 by screws 21/1. A driver wedge 23 on the bearing element 16 engages in a corresponding recess in the aluminum tube 13 of the heating roller 11 and thus ensures a secure drive connection. The bearing flange 14 is detachably connected to the frame 10 of the fixing station via wing screws 24. The heating roller 11 is secured with respect to the bearing flange 14 with the aid of holding claws 26 fastened via wing screws 25. For this purpose, the holding claw 26 has a shoulder 27 which engages in a groove 28 of the heating roller, the shoulder 27 not touching the groove 28 in the installed state, so that the heating roller 11 can move radially freely. The holding claw 26 has a securing function when replacing the fixing roller 11.

To replace the fixing roller, the wing nuts 24 are loosened and the fixing roller 11 can ge together with the flange 14 secured by the holding claws 26 with the aid of a handle 29 fastened to the bearing flange 14 from the frame 10 of the fixing station and exchanged. So that the fixing roller 11 is not damaged on its outer surface, a retaining ring 24/1 receiving the wing screws 24 is covered on the inside with felt 24/2.

In the fixing roller 11 there is a radiator module 30 consisting of several, e.g. two two halogen spotlights arranged one above the other. This radiator module is designed to be interchangeable. For this purpose, it is guided on one side in the holding and guide opening 15 of the bearing flange 14 and on the other side at an angle 31 which serves as a spacer and which is fastened on the bearing element 16 on the drive side of the fixing station. The angle 31 has a through opening 32, which is used to guide and hold the radiator module 30. In order to be able to replace the radiator module 30 even when hot, a handle 33 made of heat-insulating plastic is arranged on the other end of the radiator module. This grip piece has an extension 34 which centers the radiator module 30 in the through opening 32. The radiator module 30 can be fastened in the through opening 32 via the extension 34 with the aid of a clamping device in the form of a clamping screw 35.

For safe guidance of the radiator module made of glass, the radiator module has on one side a spacer (sleeve) 36 made of sheet metal, which holds the radiator module securely in the holding and fixing opening 15 of the bearing flange 14. The sleeve 36 can also be part of the bearing flange 14 or it can be pushed over the radiator module as an independent element before installation. Further heat protection elements are funnels 37 made of aluminum sheet with a central through opening for the radiator module, which are arranged on both sides in the aluminum tube 13 of the fixing roller 11 are not. The funnels shield the actual heat-generating area of the radiator module 30 with the filaments arranged therein from the bearings and thereby prevent the bearings 19/1, 19/2 from overheating. Such protective measures are necessary because the roller temperature on the outer surface of the fixing roller can be 215-225 ° during the actual printing operation.

The radiator module 30 is electrically contacted via a plug 38 arranged in the region of the handle 29 and a further plug 39 in the region of the bearing flange 14.

The radiator module 30 can now be easily replaced by the operator even when hot. For this purpose, first the plug 39 and then the wing screws 24 are loosened and then, according to the illustration in FIG. 3, the radiator module can be pulled out of the fixing roller 11 on the handle 33. The angle 31 serving as a spacer element ensures safe contact-free removal.

The printing device now additionally has, in a special non-heat-sensitive area, a holding device 40 with two support elements 41, which serve to receive the radiator module during the cooling phase (FIG. 3). In the meantime, until the radiator module has cooled sufficiently, a new radiator module can be inserted into the fixing roller 11 and fixed using the clamping device 35. This insertion is facilitated by a centering attachment 42 on the bearing flange 14 (FIG. 2). If the plug 39 of the electrical connection is installed stationary in the area of the bearing flange, the centering effect of the holding and fixing opening enables reliable and damage-free contact between the plug 39 and the radiator module 30. As already described at the beginning, the heating or fixing roller 11 can also be exchanged in the hot state. For safety reasons, it is necessary to do this beforehand with the radiator module 30 to remove. Furthermore, the fixing station must be in an operating state in which the pressure roller 9 is pivoted away from the fixing roller 11. An oiling device, not shown here, on the fixing station must also be swiveled out. Now the wing screws 24 on the bearing flange 14 on the operator side are loosened. The operator follows

4, the roller on the handle 29 from the drive flange 16 and pulls it through the side plate 10 out of the device. The fixing roller 11 is then placed on a e.g. Cooling shelf 51 arranged above the fixing station is placed with trestles 52. The cooling shelves can be arranged anywhere on the device or it is possible to assign a special cooling shelf on a separate frame to near the device.

A second bearing flange 14 is placed in a new fixing roller 11 and fastened to it with the holding claws 26. Bearing flange 14 with roller 11 are now inserted in the fixing station in the reverse order to that previously described. The operator can change the heating roller without tools.

The pressure roller 9 is also exchangeably mounted in the fixing station. This is described in more detail below with reference to FIGS. 5 to 8.

The pressure roller 9 consists of a steel tube 53 which is 12 mm thick with silicone rubber 54 and approx. 1 mm thick

PFA layer is covered. The pressure roller is designed as a hollow roller and has a permanently installed ball bearing 55 at both ends. The pressure roller 9 is mounted between the two vibrations 8, namely on one side (drive side) via a fixed pin 56 and on the operating side via a movable mounting pin 57 The movable locating pin 57 is axially displaceably supported in a guide sleeve 58 against the force of a spring 59 and has an operating head 60 in the form of a spherical head with which the movable bolt 57 can be pulled out of the ball bearing 55. In addition, the locating pin 57 is connected to a cup-shaped sleeve 61 which is guided on the guide sleeve 58. The sleeve 61 has a collar-shaped projection 62 which interacts with a stop 63 of the fixing station. Collar-shaped stop 62 and stop 63 serve as a locking device. Only when the pressure roller 9 is pivoted away from the fixing roller 11 is the collar-shaped projection 62 outside the effective range of the stop 63 and the movable locating pin 57 can be withdrawn via the control button 60 and thus the pressure roller 9 can be unlocked. If the pressure roller 9 is pivoted, the stop 63 prevents the connection between the movable locating pin 57 and the pressure roller 9 from being released. The locking stop 63 is also coupled to a roller saddle (paper guide), not shown here, arranged underneath the fixing station, in such a way that the locking of the Pressure roller 9 can only be released when this so-called roller saddle is open. This is to prevent jamming of the roller saddle or damage to the roller saddle.

The pressure roller is swiveled in and out onto the fixing roller 11 with the aid of a stepper motor 64, which has a

Claw clutch 65 engages on a camshaft 66, on which the two cam disks 7 are fastened. The camshaft 66 is mounted in the frame 10 of the device via an adjusting mechanism 67, which is used to adjust the pressure spring force of the pressure roller. The cam disks 7 bear on the pressure elements 6 of the rockers 8 under the action of the springs 5. The rockers 8 are in turn pivotable about the axis 4 via bearings 68. To set the pressure spring force, two adjusting screws 69 are arranged on the adjusting mechanism 67 (FIG. 7), by means of which the position of the camshaft 66 in relation to the pressure roller 9 can be changed or adjusted.

In order to be able to sense the position of the camshaft and thus the position of the pressure roller 9 is arranged on the camshaft 66, a scanning device 70 in the form of a Hall generator. This scanning device supplies the corresponding shaft position in the form of scanning signals to the control arrangement of the printing device or to a corresponding monitoring device for controlling the paper flow.

If the pressure roller 9 is to be exchanged when the fixing roller 11 is in the swiveled-out state, the locking between the movable mounting pin 57 and the pressure roller 9 is released by pulling the control button 60, as shown in FIG. The pressure roller can then be removed from the fixing station from below, preferably with protective gloves. Protective gloves 50 are necessary if the pressure roller 9 is to be replaced together with the hot roller exchange when the fixing station is hot.

Reference list

5 feathers

6 approach

7 cam disc

8 wings

9 pressure roller

10 frame

11 fixing and heating roller

12 Teflon coating

13 aluminum tube

14 bearing flange

15 holding and guiding opening

16 bearing element

17 drive device

18 pulley

19/1 bearings

19/2 warehouse

20 centering piece

21 centering approach

21/1 screws

22 disc springs

22/1 disc

23 driver part

24, 25 wing screws

24/1 bracket

24/2 felt

26 holding claws

27 approach

28 groove

29 handle

30 spotlight module

31 angles

32 through opening

33 handle

34 approach

35 clamping screw 36 sleeve

37 funnels

38, 39 plug

40 bracket (parking position)

41 support elements

42 centering approach

50 protective gloves

51 Cooling shelf for the fuser roller 52 support blocks

53 tubular steel

54 silicone rubber

55 ball bearings

56 fixed bolts

57 movable locating pin

58 guide sleeve

59 spring

60 control head

61 case

62 collar-shaped approach

63 stop

64 stepper motor

65 claw coupling

66 camshaft

67 Adjustment mechanism

68 bearings

69 adjusting screws

70 scanner

Claims

1. Fixing station for an electrophotographic printing or copying device with an electrically heated fixing roller (11) and a pressure roller (9) which can be pivoted on and off the fixing roller (11) via a fastening mechanism (8, 7),

characterized in that the fixing roller (11) and / or the pressure roller (9) are mounted in the fixing station via bearing elements (14, 16) detachable from outside the fixing stations, the bearing elements (14, 16) being designed such that an exchange of the Rolling (11, 9) is possible even in the hot operating state.

2. fuser according to claim 1,

characterized in that the fixing roller (11) is designed as a hollow roller with heating elements (30) arranged therein and is mounted in a frame (10) of the fixing station via bearing flanges (14, 16), a first bearing flange (16) fixed to the frame (10) assigned and a second bearing flange (14) is detachably attached to the frame (10) and that the second bearing flange (14) has detachable holding elements (26) for the fixing roller (11), such that the fixing roller (11) is replaced after loosening of the second bearing flange (14) from the frame (10), the bearing flange (14) via the holding elements (26) detects the fixing roller (11) to be replaced, so that it can be pulled out of the fixing station via the bearing flange (14) and then the bearing flange (14) is placed on another replacement fixing roller and fastened in the fixing station via the bearing flange (14).

3. fuser according to claim 2,

That is, the interchangeable second bearing flange (14) has a handle element (29).

4. fuser according to one of claims 2 or 3,

characterized in that the bearings have flanges (14, 16) in the fixing roller (11) laterally engaging centering elements (20, 21) on which the fixing roller (11) slides and that on at least one of the bearing flanges (14, 16) spring elements (22) to compensate for thermal axial movement of the fixing roller are arranged, which clamp the fixing roller (11) between the bearing flanges (14, 16).

5. fuser according to one of claims 2 to 4,

That is, heat protection elements (37) are arranged in the fixing roller, which shield the bearing flanges (14, 16) from an area heated by the heating elements.

6. fuser according to one of claims 2 to 5,

characterized in that the bearing flanges (14, 16) have central receiving openings (15, 32) for exchangeably receiving heating beams combined to form a radiator module (30), which are arranged such that the radiator module (30) is exchanged without removing the fixing roller (11) can be.

7. fuser according to claim 6,

That is, the radiator module (30) has a receiving area at one end for receiving a thermally insulating handle (33).

8. fuser according to one of claims 1 to 7,

Because of this, the pressure roller (9) is detachably mounted between two rockers (8) which can be pivoted on and off about the axis (4) via an eccentric device (66, 7) driven by an electric motor to the fixing roller (11).

9. fuser according to claim 8,

characterized in that the eccentric device (66) has a camshaft (66) arranged thereon Neten cam discs (7), the camshaft (66) via an adjusting mechanism (67) with respect to its position relative to the rocker arms (8) to be actuated.

10. fuser according to one of claims 1 to 9,

That is, the pressure roller is detachably mounted via a fixed pin (56) and a pin (57) movable against a spring (59), the movable pin (57) having an operating button (60).

11. fuser according to one of claims 1 to 10,

d a d u r c h g e k e n n e e c h n e t that a cooling tray (40, 41, 51, 52) for the heated fusing roller (11) and / or a radiator module (30) is arranged in the electrophotographic printing or copying machine.