KR20060113140A - Transfer unit for image forming apparatus - Google Patents

Abstract

A transfer unit of an image forming device is provided to minimize or remove a path secession and slanted running of a transfer belt. A transfer belt(110) includes guide rails(111,111') formed along the both side surfaces thereof. A series of guide grooves(112,112') are formed at the outside of the guide rails. The guide rails are made of urethane rubber. The shape of the guide grooves is one of circular, rectangular, triangle and the like. A protection tape is preferably formed at the guide groove forming portion. A driving roller(120) rotates the transfer belt. A tension roller(130) controls the tension of the transfer belt.

Description

Transfer unit of image forming apparatus {TRANSFER UNIT FOR IMAGE FORMING APPARATUS}

1 is a view schematically showing an example of a general electrophotographic image forming apparatus;

Figure 2 is a perspective view showing an extract of the transfer unit in the image forming apparatus of Figure 1,

3 is a perspective view of a transfer unit according to an embodiment of the present invention;

Figure 4 is an exploded view of the main portion of the transfer unit according to an embodiment of the present invention,

5 is a detailed view of the belt guide means that is the main part of the present invention;

6A and 6B are perspective views of the first guide bush and the second guide bush constituting the belt guide means of FIG. 5, and

Figure 7 is an enlarged view of the main portion of the transfer belt constituting the transfer unit according to the present invention.

<Description of Symbols for Main Parts of Drawings>

110; transfer belt 111, 111 '; guide rail

112, 112 '; guide groove 120, 130, 140; roller

Belt guide means 210,230; first and second guide bushes

211,231; Axis 212; Guy dribble

213,233; Springgo Information 232; Guide protrusion

250; pressure spring

The present invention relates to a transfer unit of an image forming apparatus such as a printer, a facsimile, a copying machine, or the like for forming an image using electrophotographic technology.

In general, image formation using electrophotographic technology forms an electrostatic latent image on the surface of a photosensitive member, and attaches toner on the electrostatic latent image to make a visible image, and then the visible image is directly or through an intermediate transfer medium. It transfers to the recording medium and is fixed.

FIG. 1 is a schematic view of a color laser beam printer, which is one of electrophotographic image forming apparatuses, in which reference numeral 11 denotes a photosensitive member, and 12 denotes a laser that scans the photosensitive member 11 to form an electrostatic latent image. A scanning unit 13 for developing a electrostatic latent image of the photosensitive member 11 with toner, 14 a transferring unit for transferring a visible image of the toner of the photosensitive member 11 to a recording medium, and 15 for transferring to a recording medium. A fixing unit for fixing a visible image by toner, a feeding unit for supplying a recording medium, and 17 a discharge unit.

As shown in FIG. 2, the transfer unit 14 includes an endless orbital transfer belt 21 which is circumscribed with the photosensitive member 11, and a plurality of rollers 22 for rotationally driving the transfer belt 21 in a predetermined path. And a transfer housing 25 for supporting the transfer belt 21 and the plurality of rollers 22, 23, 24, and the like. In addition, a guide member 26 is formed outside the transfer housing 25, and the guide member 26 is slidably coupled to the guide rail 27 provided in the image forming apparatus main body. The position of the transfer unit is fixed.

Since the meandering and dislocation of the transfer belt 21 in the transfer unit 14 has a fatal effect on the image transfer, a belt guide device is required to allow the transfer belt 21 to stably run without departing from the path. . For this purpose, although not specifically illustrated in the general transfer unit, by attaching the guide rubber along both sides or one peripheral edge of the transfer belt 21 and by installing a structure for guiding the guide rubber on both sides of the roller to remove the meandering and positional deviation of the transfer belt. A belt guide device to prevent this is adopted.

However, the belt guide device as described above has a problem that the belt is easily detached due to contact load generation as well as noise caused by friction between the guide rubber of the transfer belt and the guide structure of the roller.

In addition, when a portion that is distorted due to dimensional error and environmental change of various parts is difficult to predict the running of the belt, there is a fear that the belt is separated.

In other words, in order to prevent the belt from being detached, the conventional transfer unit has a mechanism such as a difference in tension force between both ends of the belt, parallelism between the rollers, deformation states such as warping of the transfer housing itself, and a seating state of the transfer unit with respect to the main body of the image forming apparatus. Dimensional control of the parts is required, which is difficult to quantitatively measure and often depends on more variables depending on the configuration of the system, and environmental effects must be considered. Experiment is necessary.

For this reason, when the belt meanders or is out of position, problems such as wrinkles of the belt, poor image alignment, poor cleaning, and noise generation are serious. Therefore, there is a demand for the development of a belt guide device to prevent the meandering and deviation of the belt.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to provide a transfer unit of an image forming apparatus, in which a transfer belt can stably travel without deviation of a path without being affected by dimensional changes or environmental changes of various parts. have.

The transfer unit of the image forming apparatus according to the present invention for achieving the above object, an orbital transfer belt formed with a guide rail and a series of guide grooves, respectively, along both peripheral edges; At least two rollers for rotating the transfer belt in a given path; And belt guide means respectively installed in cooperation with the guide rail and the guide groove so that the transfer belt does not deviate from the path so as to guide the transfer of the transfer belt to both sides of one of the two rollers. It features.

According to a preferred embodiment of the present invention, one of the two rollers is a drive roller for rotationally driving the transfer belt, the other is a tension roller for adjusting the tension of the transfer belt, the belt guide means is installed on the tension roller It is good to be.

The belt guide means may include: a first guide bush installed in the tension roller and having a guide rib in contact with the side wall of the guide rail to assist driving of the transfer belt; And a second guide bush installed in the tension roller so as to be positioned outside the first guide bush and having a plurality of guide protrusions radially protruding from the guide groove of the transfer belt. Here, the first and second guide bushes preferably have an outer diameter less than or equal to the outer diameter of the tension roller.

In addition, a plurality of pressure springs may be installed between the first and second guide bushes to elastically support the second guide bush to the outside to tension the transfer belt in the scanning direction. Here, the pressure spring is preferably three, and the first and second guide bushes are formed to correspond to the spring high information for supporting the three pressure springs.

In addition, it is preferable that a protective tape is attached to the guide groove of the transfer belt to reinforce the strength of the transfer belt. In this case, the protective tape is preferably made of PET, but the material is not necessarily limited thereto.

In addition, according to a preferred embodiment of the present invention, the transfer unit of the image forming apparatus is preferably provided with a backup roller for cleaning while maintaining the endless track shape of the transfer belt.

The above objects and other features of the present invention will become more apparent by describing the preferred embodiments of the present invention in detail with reference to the accompanying drawings. For reference, in the following description of the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 is a perspective view of a transfer unit according to an embodiment of the present invention, Figure 4 is an exploded view of the main portion of the transfer unit according to an embodiment of the present invention.

As shown in Figures 3 and 4, the transfer unit of the image forming apparatus according to an embodiment of the present invention is a transfer belt 110 on an endless track, a plurality of rollers for rotating the transfer belt 110 in a given path (120) 130, 140 and the belt guide means 200, 200 'to prevent the meandering and path deviation of the transfer belt 110.

As shown in FIGS. 4 and 7, the transfer belt 110 is formed outside the guide rails 111 and 111 ′ and the guide rails 111 and 111 ′ which are respectively formed along the peripheral edges thereof. It is provided with a series of guide grooves 112, 112 '. The guide rails 111 and 111 ′ may be formed of urethane rubber, and the guide grooves 112 and 112 ′ may have any shape such as a circle, a rectangle, and a triangle. In addition, it is preferable to attach a protective tape (not shown) made of PET or the like to the guide grooves 112 and 112 ′ forming portions to prevent the strength of the transfer belt 110 from being lowered due to the formation of such grooves. Do.

The rollers 120, 130 and 140 are a driving roller 120 for rotating the transfer belt 110, a tension roller 130 for adjusting the tension of the transfer belt 110, and a cleaning unit backup roller ( 140) and the like. By these rollers 120, 130, 140, the transfer belt 110 maintains a predetermined path and moves in an endless track.

The rollers 120, 130, 140 are supported by the transfer housing 150. Although not specifically illustrated, the transfer housing 150 includes first and second housing members, and a handle member 151 is installed at an upper portion thereof. In addition, the housing 150 supports the cleaning unit 160 (see FIG. 4), and includes a color balance sensor and a waste toner recovery unit.

The belt guide means 200 and 200 ′ cooperate with the guide rails 111 and 111 ′ and the guide grooves 112 and 112 ′ of the transfer belt 110 so that the transfer belt 110 deviates from the path. By guiding the vehicle to stably run, it is provided on both sides of the tension roller 130, respectively.

The belt guide means 200 and 200 ′ (only one belt guide means 200 will be described since it is the same configuration), as shown in FIGS. 4 to 7, the first guide bush 210 and the second guide. Bush 230 and a plurality of pressure springs (250).

As shown in FIGS. 5 and 6a, the first guide bush 210 contacts the sidewall of the guide rail 111 of the transfer hole 110 and the shaft hole 211 for coupling with the tension roller 130. It is provided with a guide rib 212 to prevent separation. In addition, the first guide bushing 210 is also provided with a plurality of spring height information 213 (three in the illustrated example) for fixing the pressing spring 250 to be described later. The first guide bush 210 may be formed of metal or plastic, but may be formed of a plastic material in consideration of wear of the transfer belt 110. In addition, the first guide bush 210 is configured to rotate together with the tension roller in a coupling structure such as a D-cut structure or an interference fit to the tension roller 130.

As shown in FIGS. 5 and 6B, the second guide bush 230 has a plurality of guide protrusions 232 inserted into the guide grooves 112 of the transfer belt 110 on the shaft hole 231 formed at the center thereof. ) Is formed radially. In addition, the second guide bush 230 also includes a plurality of spring height information 233 for fixing the pressure spring 250 similarly to the first guide bush 210. The guide protrusions 232 are not necessarily limited to three in the illustrated example, but considering the side of maintaining the interval of the guide groove 111 of the transfer belt 110 in consideration of the strength side or more, three Or four is suitable. The material, the tension roller coupling structure, and the like of the second guide bush 230 are the same as the first guide bush 210.

The pressure spring 250 serves to maintain the scan direction tension of the transfer belt 110 by elastically biasing the second guide bush 230 outward between the first and second guide bushes 210 and 230. . As a result, the transfer belt 110 may be prevented from being relaxed or wrinkled in the scan direction while driving. The pressure spring 250 may be three as shown in the example, but is not necessarily limited thereto.

On the other hand, the first and second guide bushes 210 and 230 have an outer diameter less than or equal to the outer diameter of the tension roller 110. As a matter of course, otherwise, the planar direction of the transfer belt does not match, which causes difficulty in image transfer.

In the transfer unit of the image forming apparatus according to the present invention configured as described above, the first and second guide bushes 210 and 230 are coupled to both sides of the tension roller 130 so as to rotate together with the tension roller. These first and second guide bushes 210 and 230 are elastically biased in the opposite direction by the pressing spring 250 interposed therebetween, and the second guide bush 230 is supported by the transfer housing. It does not deviate in the axial direction.

When such a transfer unit is mounted and operated in the image forming apparatus main body, for example, when the transfer belt 110 is rotated, the guide rib 212 of the first guide bushing 210 is a guide rail of the transfer belt 110. It contacts the side wall of 111 to help the belt run. The guide protrusion 232 of the second guide bush 230 is fitted into the guide groove 112 of the transfer belt 110 to allow the belt to stably run without departing from the path.

As such, the present invention guides the running of the belt while the primary belt guide by the first guide bush 210 and the secondary belt guide by the second guide bush 230 are guided at the same time, so that the belt deviates from the path or meanders. This can reduce problems such as

That is, since the second guide bush fixes the belt against the change in the belt length due to the dimensional change of the part or the environmental change, it is possible to run the belt stably. In addition, the change in tension of the tension roller of the belt can be minimized by the pressure spring between the guide bushes.

The present invention has been described in an exemplary manner. The terminology used herein is for the purpose of description and should not be regarded as limiting. Many modifications and variations of the present invention are possible in light of the above teachings. Accordingly, the invention may be freely practiced within the scope of the claims unless otherwise stated.

According to the present invention as described above, it is possible to minimize and eliminate the path deviation or meandering of the transfer belt, so that various problems caused by the meandering of the transfer belt during printing, that is, wrinkled belt, misalignment, poor cleaning and noise It can prevent such problems.

Claims (5)

An endless track transfer belt having guide rails and a series of guide grooves respectively formed along both peripheral edges thereof; At least two rollers for rotating the transfer belt in a given path; And Includes a belt guide means for cooperating with the guide rail and the guide groove so that the transfer belt does not deviate from the path, each of the two rollers to guide the running of the transfer belt on either side of the rollers; A transfer unit of an image forming apparatus. The method of claim 1, One of the two rollers is a driving roller for rotationally driving the transfer belt, the other is a tension roller for adjusting the tension of the transfer belt, the belt guide means is a transfer roller of the image forming apparatus, characterized in that installed in the tension roller. unit. The method of claim 2, wherein the belt guide means, A first guide bush installed in the tension roller and having a guide rib in contact with the side wall of the guide rail to assist driving of the transfer belt; And And a second guide bush installed in the tension roller so as to be positioned outside the first guide bush and having a plurality of guide protrusions radially protruding from the guide groove of the transfer belt. Transcription unit. The method of claim 3, wherein A transfer unit of the image forming apparatus, wherein a plurality of pressure springs are provided between the first and second guide bushes to elastically support the second guide bush to the outside to tension the transfer belt in the scanning direction. The method according to any one of claims 1 to 4, The transfer unit of the image forming apparatus, characterized in that a protective tape is attached to the guide groove of the transfer belt to reinforce the strength of the transfer belt.

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