JPH03186881A - Apparatus for supplying releasing liquid to surface of fixing roller for electrophotographic type printer or copying apparatus - Google Patents

Abstract

PURPOSE: To realize the accurate quantity adjustment of supplied releasing liquid by regulating the quantity adjustment width of a quantity adjusting element in relation to the relative turning position of a control element. CONSTITUTION: Based on the relative turning of a quantity adjusting tube 31 and a control wedged body 33 rotatably arranged inside the tube 31, an outflow aperture 32 finely distributed to the tube 31 is closed or opened. Therefore, the necessary quantity adjustment length of the tube 31 is accurately regulated in accordance with the width of a recording supporting body on which an image should be fixed. In such a case, the regulation of the quantity adjustment length is manually performed or it is performed through a regulation motor connected to the controller of a printing device or copying device. Thus, in the case of inserting the recording supporting body in the electrophotographic printing device or copying device, oil supply width to a fixing roller is automatically regulated in accordance with the recording supporting body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a device for supplying a release liquid to the surface of a fixing roller of an electrophotographic printing device or a copying device, the device including A pressing body brings the application element in contact with the guide of the pressing body into contact with the fixing roller, and a feeding element is provided in a chamber formed by the pressing body and the application element. The mold release liquid is supplied to the application element via the supply element.

[Prior Art 1] In reproduction machine technology and electrophotographic printers, a latent charge image is formed on an intermediate support, such as a photoconductive drum, and
This latent charge image is then colored by a developer mixture in a developer station based on electrostatic forces. The colored charge latent image is transferred in a transfer station to a recording support in the form of a discrete sheet or endless paper and subsequently thermally or chemically fixed. Regarding thermal fusing, it is known from US Pat. No. 3,324,791 to use a fusing station with two rollers, between which the support of the toner image is passed. . The fuser roller facing the toner image is heated, and the other roller presses the support bearing the toner image against said fuser roller.

In this case, the toner is fused by heat and pressure.

To prevent toner from remaining suspended on the surface of the fuser roller, said surface is moistened with a release liquid, such as silicone oil. In order to apply such a release liquid to the fixing roller, West German Patent No. 2703382
It is known to use a coated wick system according to US Pat. This application wick system has a pressure body through which the felt is tensioned. The felt, together with the pressing body, forms a chamber for accommodating the mold release liquid.

In this chamber itself, a distribution element in the form of a wick is arranged, via which the release liquid is supplied from the 7-elt to the actual application element.

In order to apply the release liquid to the fixing roller, the pressing body presses the application element against the fixing roller.

In order to adapt the surface wetting of the fuser roller to the paper width, a plurality of chambers for release liquid may be arranged side by side along the fuser roller. The individual chambers can be shut off, so that release liquid is only supplied to those chambers which are located opposite the area of the surface of the fuser roller which is to be moistened with release liquid.

Graduated connection for adjustment to the width of the recording support
The shutoff is imprecise and leads to an excess of oil in the area of the applicator element. Such an excess of oil can have an adverse effect on the type quality and, moreover, special equipment is required to remove the excess oil.

[Problem to be Solved by the Invention] The problem to be solved by the present invention is to improve the device of the type mentioned at the beginning,
Accurate metering of the supplied mold release liquid is possible, and
It is an object of the present invention to provide an apparatus that allows the use of mold release liquids of various viscosities without adding a metering device.

[Means for Solving the Problem] In order to solve this problem, the present invention provides a device of the type mentioned at the outset, in which the supply element is configured as a metering element, and the metering element:
a metering tube extending along the application element and provided with an outflow opening; in the metering tube a control in the form of a cylinder jacket cut along an axially sloped cutting line; an element is rotatably arranged such that the outlet opening arranged along the metering tube is closed or opened by relative rotation of the control element; The metering width of the metering element is adjustable in relation to the relative rotational position of the metering element.

Advantageous developments of the invention are described in the subclaims.

[Effects of the Invention] According to the present invention, a metering tube and a rotatable control wedge disposed inside the metering tube have finely distributed outflow openings in the metering tube based on relative rotation. close or open. Thereby, the required metering length of the metering tube can be precisely adjusted in accordance with the width of the recording support to be fixed. Since the control wedge scrapes the opening with one of its edges when the opening is opened and when it is closed, dirt cannot build up in the opening and the opening is constantly cleaned.

In an advantageous embodiment of the invention, a correspondingly regulated delivery of mold release liquid is supplied to the metering tube in a time-controlled manner via a pump device in conjunction with the regulated metering length. This prevents excess oil from flowing out when adjusting the full width of the metering tube.

In this case, the metering length can be adjusted manually or also via an adjusting motor, which is connected, for example, to the control device of the printing or copying device. Accordingly, when the recording support is inserted into an electrophotographic printing device or a copying device, the oil supply width to the fixing roller can be automatically adjusted to match the recording support.

[Example) In the following, embodiments of the invention will be explained in detail with reference to the drawings.

In an electrophotographic printing apparatus (not shown), a device shown in FIG. 1 for supplying a release liquid to the surface of a fixing roller is provided inside a thermal fixing station. This principle diagram shows a fixing roller lO, which rotates in a clockwise direction, that is to say in the direction indicated by the arrow 1■. The pressure roller of the fusing station and the recording support guided between the two rollers are not shown. However, a device is shown for supplying a release liquid to the surface of the fixing roller IO. Advantageously, a felt strip L2 is used as application element for silicone oil or another heat-resistant release liquid, the width of which corresponds to the axial length of the fuser roller IO. . The felt strip 12 is brought into contact with the fusing roller 10 in a defined circumferential area (as will be explained in more detail later).

Due to the continuous contact with the fixing roller IO in operating conditions, the felt strip 12 wears out and, in particular, this seven-elt strip accumulates over time with dirt particles, such as toner particles or dust entrained by the recording medium. In order to ensure satisfactory functionality, the area of the felt strip 12 that contacts the fusing roller 10 is refreshed slowly continuously or, if appropriate, stepwise at time intervals. It is advantageous. For this purpose, a storage roll 13 and a storage roll 1 are required.
4, in which case the felt strips 12 are withdrawn from the storage roll, and the receiving roll receives the used felt strips 12. The receiving roll 14 is, as shown, driven, for example, by a motor 15 and is moved in the counterclockwise direction in this case. The resulting transport direction of the seven-elt strip 12 extends against the movement of the fuser roller IO, so that the used felt strip is free of all impurities received by scraping the surface of the fuser roller IO. A sufficient area of entrained and relatively fresh felt strips is always provided.

In order to obtain a satisfactory functioning of the felt strip 12, i.e. a metered supply of release liquid and the desired cleaning of the fuser roller 10, it is necessary to apply said felt strip to the fuser roller lO in a defined manner, i.e. within a predetermined range. It is necessary to make contact as uniformly as possible and with a predetermined pressing force. In this case, the pressing device that fulfills this function is cut out from the base body 16, and it is advantageous that the length of this base body is slightly longer than the length of the fixing roller 10 in the axial direction. are manufactured, for example, from extrusion press profiles. Two chambers 17 are arranged in mirror symmetry in this base body 16, extending parallel to the longitudinal axis of the base body and opening in the direction of the fusing roller IO. The cross section of these chamber openings is formed in such a way that one side wall occurs on each side of the base body,
In this case, said side wall has a retaining strip 18 which projects inwardly in a tangential direction with respect to the fusing roller IO. The inner wall of the chamber 17, ie the wall of the base body 16 opposite the narrow side, has in each case a guide groove 19 arranged parallel to the axis, which guide groove extends at least half way into the groove bottom. It has a circular cross section, and the side walls are slightly chamfered.

The guide groove 19 accommodates in each case a corresponding spherically shaped bearing rib for one of the two pressure strips 21 . This pressure strip 21 has, on the side facing the bearing rib 20, a further lateral projection 22 which engages the corresponding holding strip 18 of each chamber 17 from behind with sufficient play. It matches. The body of the pressure strip 21 is designed in the direction of the fusing roller 10 as a pressure rib 23 with a rounded chamfer. On the bottom side of the pressure strip 21 opposite this pressure rib, a cutout is provided for accommodating a spring element 24, which spring element moves the pressure strip 21 away from the basic body 16? is pressed in the direction of the fixing roller 10.

Due to the pivotable bearing type, as indicated by the arrow, of the pressure strip 21 on the basic body 16, the felt strip 1
2 can contact the fixing roller 0 uniformly and with sufficient pressing force regardless of the error of the felt strip 12 itself and the positioning error of the base 16 with respect to the fixing roller 10 in the approach range and the advance range of the device. Being a distant relative. As a result, the felt strip wraps around the fixing roller in an area defined by the distance of the rounded pressure ribs 23, so that the fixing roller 10 is evenly wiped and subsequently moistened again with release liquid. This can be assisted by braking the storage roll 13 against its direction of rotation, thereby maintaining a predetermined tension in the felt strip 12.

The release liquid is supplied from a reservoir, which is connected to the supply conduit 25 via a pump 30. This supply line ends in a connection region 26 for the metering device shown in FIG. Via this metering device, the mold release liquid is delivered to the felt strip 12, whereby the mold release liquid is sucked in by this felt strip due to capillary forces in the felt strip.

A metering element shown in FIG. 2 is provided for metering release liquid to the application element 12 made of felt. This metering element is dispensing element 1.
It has a metering pipe 31 extending over the entire width of 2,
This metering tube has a diameter of about 0.5
It has an outflow opening 32 in the form of a hole with a diameter of mm.

The metering tube has a diameter of 2 mm, for example. A control element 33 is rotatably arranged in this metering tube. This control element is cut in the shape of the cylinder jacket, ie in the axial direction, along a cutting line 34 which has a uniform slope in the axial direction and also forms the edge of the control element. It has the shape of a cylinder jacket. Instead of a uniform slope of the cutting line, a slightly curved slope or a partially stepped slope is also possible. In this case, the slope of the cutting line is associated with a metering function. At certain distances along the control element 33, support rings 35 are arranged on said control element, which serve to guide the control element 33 in the metering v31. The control element is rotatably mounted on the metering tube 31 via the support ring 35 and an additional element 36 arranged in the inlet region of the metering tube 31, in which case the additional element of the control element 33 36 projects from the metering tube 31 and is connected to a gearwheel 37, for example. This gear 37 is connected to the control gear 1-33,
Adjustment motor 3 configured as a stepper motor, for example
8.

Depending on the relative pivoting position of the control element 33 with respect to the metering tube 31 fixed by the holding device 39, the outflow opening 32 opens more or less 5°, so that the metering width is determined by the relative pivoting position of the control element 33. can be changed in relation to.

In order to achieve sufficient linearity when adjusting the metering range,
Preferably, a rotation range of about 90° is provided between the fully closed position and the fully open position of the metering tube 31.

The adjustment range or adjustment width takes place via the adjustment motor 38 in relation to the width of the recording medium to be fixed via the fixing roller 10. This means that, for example, when a recording support is inserted into a paper guide of a printing device, said printing device detects the width of the recording support in a general manner and the control device S
This can be done by applying a corresponding adjustment signal to the adjustment motor 38t via the adjustment motor 38t to adjust the adjustment range.

In this case, it is necessary that the recording support always be in contact with its side edges in the area of the fixing roller IO or the front edge of the metering element.

In order to adjust the amount of mold release liquid discharged by the pump 30 in accordance with the metered amount adjusted based on the metered width,
The release liquid is time-controlled via the pump 30 by the control device S of the printing device in relation to the fixed recording carrier width, so that, for example, at the completely open outflow opening 32, i.e. at the widest adjustment This prevents an excessive amount of release liquid from being supplied to the felt. Therefore, by additional timing control of the pump 30, the amount of mold release liquid to be conveyed can be accurately controlled.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, in which FIG. 1 is a sectional view of an apparatus according to the invention for supplying release liquid to a fixing roller of an electrophotographic printing device, and FIG. 2 is a cross-sectional view of a metering device. FIG. IO...Fixing roller, ll...Arrow, 12...Felt strip, 13...Storage roll, 14...
Accommodation roll, 15... Motor, 16... Base, 17
... Chamber, 18... Holding strip, 19... Guide groove, 20... Supporting rib, 21... Pressing strip, 22...
...Protrusion 23...Press rib, 24...Spring element, 25...Supply conduit, 26...Connection range, 30...
... Pump 31 ... Metering pipe, 32 ... Outflow opening, 3
3... Control element, 34... Cutting line, 35
...Support ring, 36...Additional member, 37...Gear, 38...Adjustment motor, 39...Holding device, 40
...front edge, D...metering width, S...control device

Claims (1)

[Scope of Claims] 1. A device for supplying a release liquid to the surface of a fixing roller (10) of an electrophotographic printing device or a copying device, wherein the releasing liquid is supplied by a pressing body (16) extending along the fixing roller. , the application element (1) in contact with the guide (23) of the pressing body
2) is brought into contact with the fusing roller (10) and is formed by a chamber (17) formed by the pressing body (16) and the application element (12);
is provided with a supply element (26), and the release liquid is supplied to the application element (12) via the supply element, the supply element being configured as a metering element, the metering element has a metering tube (31) extending along the application element and provided with an outflow opening (32);
In the metering tube there is a cutting line (34
), a control element (33) in the form of a cylinder jacket cut along the metering tube (31) is rotatably arranged, and the outflow opening (32) is arranged along the metering pipe (31).
is adapted to be closed or opened by a relative pivoting of the control element (33), the metering width of the metering element being dependent on the relative pivoting position of the control element (33). A device for supplying a release liquid to the surface of a fixing roller of an electrophotographic printing device or a copying device, characterized in that (D) is adjustable. 2. The control element (33) has a support ring (33) for guiding it in the metering tube (31).
35). 3. Device according to claim 1 or 2, characterized in that the control element (33) is connected to an adjusting motor (38) for adjusting the metering width (D). 4. Any one of claims 1 to 3, wherein the discharge amount of the mold release liquid related to the metering width (D) is supplied to the metering element via a feed pump (30). The device described. 5. Control device for electrophotographic printing device or copying device (
S) is adapted to detect the width of the recording support to be fixed and to adjust the metering width (D) of the metering element in relation to this width via the adjusting motor (38). The device according to item 3.