JPH04254868A - Fixing device - Google Patents

Abstract

PURPOSE:To select a picture image surface upward or downward to discharge a decalcomania paper to the outside of a picture image forming device by optionally switching the direction of a picture image surface when the decalcomania paper, of which picture image fixing is finished, is sheet-discharged from a fixing device. CONSTITUTION:A fixing device features that a sheet discharge roller 186, able to be transferred to the sheet-discharge part of a decalcomania paper, and a guide plate 188 are provided, and the direction of a picture image surface is regulated to be sheet-discharged by changing positions of the sheet discharge roller 186 and the guide plate 188 and switching the rotation direction of the sheet discharge roller 186.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device for an image forming apparatus that can freely select the front and back sides of transfer paper on which an image has been fixed and eject the paper.

0002

[Prior Art] In general image forming apparatuses other than copying machines, transfer sheets with images recorded on them are usually discharged onto a tray with the image side facing down and stacked in order to align the page order. is normal.

However, depending on the original, it is necessary to check the density and tone of the transferred image during the copying process.
In this case, if the image surface is facing downward, the workability is poor, so image forming apparatuses have also been provided which can arbitrarily switch the image surface facing downward or upward and eject the paper.

0004

[Problem to be Solved by the Invention] In order to turn the image side upward, a device is required to turn the transfer paper upside down, and generally the transfer paper is conveyed into a loop-shaped conveyance path via a plurality of conveyance rollers. The method used is to turn the paper upside down.

[0005] Therefore, such a device requires a large space and a large number of conveyance rollers to form a transfer path for the transfer paper, and is disadvantageous in terms of compactness and cost.

[0006] As a result of solving this problem and improving the present invention,
The purpose of this invention is to provide a fixing device that can arbitrarily select and eject transfer paper with the image side facing downward or upward without providing a conveyance path or conveyance rollers for reversing the front and back sides of the transfer paper. It is.

[0007]

[Means for Solving the Problems] The above object is to fix the transfer surface side of the transfer paper on which a toner image is attached using a high-temperature belt-like member and then eject the paper. This is achieved by a fixing device characterized by switching the rotational direction of the paper roller.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIGS. 1 to 3.

FIGS. 1 and 2 show a fixing device 1 according to the present invention.
8, numeral 181 in the figure is a heating roller with a built-in heater, which is driven and rotated clockwise in a fixed position by the power of the main body of the apparatus.

Reference numeral 182 designates a driven roller which rotates freely at a fixed position, and 183 designates a high-temperature belt-shaped member, ie, a heating belt, stretched between the heating roller 181 and the driven roller 182.

The heating belt 183 is connected to a pressure roller 184.
The transfer paper on which the image has been transferred is sandwiched between the two belts and conveyed in the direction of the arrow, while the toner image in contact with the belt surface is melted and fixed. After fixing, the transfer paper is easily separated from the belt surface around the driven roller 182, which has a small curvature, and is moved straight upward.

185 and 186 are the heating belt 1
83, one of which is a pair of paper ejection rollers 185 that is in a fixed position, while the other paper ejection roller 186 is a swinging member 187 that rotates about a shaft 187A as a fulcrum. It is supported and placed in a freely rotatable state.

That is, in the paper ejecting roller 185, a coaxially integrated gear G185 is connected to a coaxially integrated gear G182 of the driven roller 182 via intermediate gears G1 and G2, so that the heating belt 183 is rotated clockwise. The material is rotated counterclockwise at the same circumferential speed.

On the other hand, the paper ejection roller 186 is rotated counterclockwise at the same circumferential speed as the heating belt 183 by the coaxial integral gear G186 being inserted into and removed from the gear G182 via the intermediate gears G3 and G4. It is in a freely rotatable state.

When the transfer paper fixed by the heating belt 183 is to be discharged with the image side facing downward, the swinging member 187 is rotated counterclockwise as shown in FIG. The discharging roller 186 is meshed with the gear G3, thereby rotating the paper ejecting roller 186 counterclockwise at the same circumferential speed as the heating belt 183.

As a result, the transfer paper conveyed by the heating belt 183 comes into contact with the circumferential surface of the paper ejection roller 186 along the guide plate 188, and is sent to the ejection roller 19A by its counterclockwise rotational movement. , and is discharged onto the tray 20A from the direction shown by arrow B with the image surface facing downward.

On the other hand, when discharging a sheet with the image surface facing upward, the swinging member 187 is rotated clockwise as shown in FIG. 2, and the discharging roller 186 is moved to the left.
The gear G186 and the intermediate gear G3 are disengaged from each other, and the peripheral surface of the roller is brought into pressure contact with the peripheral surface of the paper discharge roller 185.

Therefore, the direction of rotation of the paper discharge roller 185 is switched clockwise, and at the same time, the rotation direction of the paper discharge roller 185 is switched clockwise.
7, the guide plate 188 rotates around its support shaft 18.
It is rotated and retracted counterclockwise using 8A as a fulcrum.

As a result, the transfer paper fixed by the heating belt 183 separates from the belt surface and travels straight upward, and then its leading end is sandwiched between the paper ejection rollers 185 and 186, and is transferred to the paper ejection roller 19B. sent to arrow C
Insert the tray 20 with the image side facing upward from the direction shown in
It is discharged onto B.

[0020] If a separating claw is brought into contact with the circumferential surface of the heating belt 183 around the driven roller 182, separation of the transfer paper becomes more reliable.

FIG. 3 shows a color image forming apparatus equipped with the above-described fixing device according to the present invention.

In the figure, reference numeral 1 denotes a flexible photoreceptor belt serving as a belt-like image carrier. conveyed in the direction.

Reference numeral 4 denotes a support member or guide member fixed to the main body of the apparatus so as to be inscribed in the photoreceptor belt 1;
The photoreceptor belt 1 is brought into a tensioned state by the outward biasing action of the rotary roller 3, so that its inner circumferential surface slides against the guide member 4. Therefore, the photoreceptor belt 1
The photoreceptor on the outer circumferential surface of the photoreceptor is always maintained at a constant position relative to the surface of the guide member 4 during transportation, making it possible to form a stable image forming surface.

6 is a scorotron charger as charging means; 7
8 to 1 are laser writing system units serving as image exposure means;
Reference numeral 1 denotes a plurality of developing means, that is, developing devices, each containing a developer of a specific color, and each of these image forming means is arranged opposite to the outer circumferential surface of the photoreceptor belt 1 with the guide member 4 as its back surface. will be established.

In addition to the optical system shown in the drawings, the laser writing system unit 7 may also include an optical system that integrates a light emitting section and a convergent light transmission body.

Each of the developing units 8, 9, 10, and 11 accommodates, for example, yellow, magenta, cyan, and black developers, respectively, and includes developing sleeves that maintain a predetermined gap from the photoreceptor belt 1. It has a function of making the latent image on the photoreceptor belt 1 visible by a non-contact development method. Unlike contact development, this non-contact development has the advantage of not interfering with the movement of the photoreceptor belt.

Reference numeral 12 denotes a transfer device, 12A denotes a charge eliminating bar, and 13 denotes a cleaning device, in which a blade 13A and a toner conveying roller 13B are kept at a position apart from the surface of the photoreceptor belt 1 during image formation. It is pressed against the surface of the photoreceptor belt 1 as shown in the figure only during post-transfer cleaning.

The color image forming process by the color image forming apparatus is performed as follows.

First, the formation of a multicolor image according to this embodiment is performed according to the following image forming system. That is, data obtained by a color image data input section in which an image sensor scans an original image is subjected to arithmetic processing in an image data processing section to create image data, which is temporarily stored in an image memory. The image memory is then taken out during recording and input to a recording section, for example, the color image forming apparatus shown in the example of FIG. 3.

That is, when a color signal output from an image reading device separate from the printer is input to the laser writing system unit 7, the color signal is generated by a semiconductor laser (not shown) in the laser writing system unit 7. The laser beam is transmitted to a polygon mirror 7 rotated by a drive motor 7A.
B, it is rotated and scanned by the mirror 7 via the fθ lens 7C.
The optical path is bent by D, 7E, and 7F, and the light is projected onto the circumferential surface of the photoreceptor belt 1, which has been charged in advance by the charger 6, which is a charging means, to form a bright line.

On the other hand, when scanning is started, the beam is detected by the index sensor, modulation of the beam by the first color signal is started, and the modulated beam scans the circumferential surface of the photoreceptor belt 1. Therefore, a latent image corresponding to the first color is formed on the circumferential surface of the photoreceptor belt 1 by main scanning by the laser beam and sub-scanning by the conveyance of the photoreceptor belt 1. This latent image is yellow (Y) in the developing means.
The toner (developing medium) is developed by the developing device 8 loaded with the toner (developing medium), and a toner image is formed on the belt surface. The obtained toner image, while being held on the belt surface, passes under a cleaning device 13, which is a cleaning means, which is separated from the peripheral surface of the photoreceptor belt 1, and enters the next copy cycle.

That is, the photoreceptor belt 1 is charged again by the charger 6, and then the second color signal outputted from the signal processing section is inputted to the writing system unit 7, and the above-mentioned first color signal Writing is performed on the belt surface in the same manner as in the case of , and a latent image is formed. The latent image is developed by a developer 9 loaded with magenta (M) toner as a second color.

This magenta (M) toner image is formed in the presence of the previously formed yellow (Y) toner image.

A developing device 10 has cyan (C) toner, and forms a cyan (C) toner image on the drum surface based on a control signal generated by a signal processing section.

Further, numeral 11 denotes a developing device containing black toner, which forms a black toner image superimposed on the belt surface by the same process. These developing devices 8, 9, 1
Direct current or even alternating current bias is applied to each sleeve 0 and 11, and jumping development is performed using a two-component developer, which is a developing means, and non-contact development is performed on the photoreceptor belt 1 whose base is grounded. It is about to be done. Note that as the development, non-contact development using a one-component developer can also be used.

The color toner image thus formed on the circumferential surface of the photoreceptor belt 1 is transferred to a transfer material fed from the paper feed cassette 14 via the paper feed guide 15 at the transfer section.

That is, the uppermost layer of the transfer material stored in the paper feed cassette 14 is carried out by the rotation of the paper feed roller 16, and transferred to the photoreceptor belt 1 via the timing roller 17.
It is supplied to the transfer device 12 in synchronization with the above image formation.

The transfer material that has undergone image transfer and static electricity removal is reliably separated from the photoreceptor belt 1, which suddenly changes direction along the rotating roller 2, and is transported upward via the suction type conveyor belt 17A. Then, the image is fixed by the fixing mount 18 of the present invention described above.

[0039] Note that the image forming apparatus has the upper part of the apparatus
Upper lid 2 that can be opened and closed, with a portion of the tray 20A as described above
0, so when handling a transfer paper jam, open the top cover 20 and then close the fixing device 1.
If the nipping surface and conveying surface of each roller 8 can be opened, work such as removing jammed paper can be performed extremely easily.

[0040]

Effects of the Invention According to the present invention, a fixing device capable of reversing the image surface of transfer paper by simply adding an extremely simple member is provided, and as a result, in particular, it is possible to reverse feed the transfer paper. A compact and low-cost image forming apparatus has been realized that can arbitrarily discharge paper with the image surface facing upward or downward without providing any mechanism or the like.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram of a fixing device when the image surface is facing downward.

FIG. 2 is a cross-sectional configuration diagram of the fixing device when the image surface is facing upward.

FIG. 3 is a sectional view of a color image forming apparatus including the fixing device.

[Explanation of symbols]

17A...Transport belt 18...Fixing device 19A, 19B...Discharge roller 20…Top lid 20A, 20B...(paper output) tray 181...Heating roller 182...Followed roller 183...Heating belt 184...Crimping roller 185, 186... Paper ejection roller 187 ... Swinging member 188...Guide plate

Claims (2)

[Claims] Claim 1: In a fixing device that fixes the transfer surface side of a transfer paper on which a toner image is attached using a high-temperature belt-like member and then discharges the paper, the direction of discharge of the transfer paper is changed by switching the direction of rotation of a paper discharge roller. A fixing device that is characterized in that it works by doing something. 2. The fixing device according to claim 1, wherein switching the rotational direction of the paper ejection roller is accompanied by movement of the paper ejection roller.