JP2000025984A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the labor of a user at the time of addressing jamming for high operability by forming a paper jam releasing means interlocking with drawing of a unit body mounted between the unit body and a sheet aligning and feeding means, from a device body and releasing the sheets jammed in the sheet aligning and feeding means. SOLUTION: When a unit body Y is drawn out of a copying machine body, a pressure condition against the pressure bracket 36 of the unit body Y is released. The pressure bracket 36 is always pulled in a particular direction, therefore it moves in that direction smoothly when pressure is released. When the pressure bracket 36 is moved in a particular direction, a roller 41 mounted on the pressure bracket 36 rolls to release pressure against a leaf spring 42, and a resist unit Ry moves in the opposite direction to U direction taken until then. In other words, a lower resist roller 20B pivoted to the resist unit Ry is separated from an upper resist roller 20A to release a pressure condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as an electronic copying machine.

[0002]

2. Description of the Related Art In an electronic copying machine, for example, paper fed from a paper feeding unit may be jammed during transportation for some reason. Therefore, various measures are provided so that the operator can easily remove the jammed paper (so-called jam processing).

As one of them, there is a structure of a copying machine main body. For example, in an electronic copying machine having a structure called a clamshell system, the copying machine body is divided into an upper unit and a lower unit. The units are connected to each other via a fulcrum, and the mating surface of each unit is a sheet transport path portion immediately below a photosensitive drum serving as an image carrier.

When a paper jam occurs, the interior of the copier main body is opened by rotating the upper unit about the fulcrum. Since the paper jammed in the conveyance path is exposed, the paper can be removed.

However, in this method, since the upper unit is rotated and opened, a large amount of labor is required for operation, and it is difficult to position the upper and lower units relative to each other during assembly. If there is a positional deviation, a paper feed error or an image deviation occurs, resulting in poor reliability.

[0006]

Therefore, a fixed frame type is adopted. That is, when a jam occurs, only one sheet of paper has been reached, and the sheet has reached the photosensitive drum unless a jam occurs on the front side of the registration roller pair. Alternatively, no matter where the paper jam occurs, it is necessary to confirm that no paper remains on the photosensitive drum and its surroundings when the paper jam is cleared.

In the case of the fixed frame type, two means are considered as means for confirming the presence or absence of a sheet around the photosensitive drum and removing the sheet when the sheet is jammed. The first means is to integrate the transfer unit and the transport belt among the registration roller pair, the transfer unit, the transport belt, and the fixing device, which are the components under the photosensitive drum, to form an end of the transport belt on the fixing device side. The structure is such that it is pivotally supported with the part as a fulcrum, and at the time of jam processing, by rotating the unit of the transfer unit and the transport belt,
This is to make a space for jam clearance below the photosensitive drum.

As a second means, a registration roller pair, a transfer unit, a transport belt, a fixing device, and the like, which are components under the photosensitive drum, are all integrated into one unit, and are detachably attached to a copying machine main body as an apparatus main body. When the jam is cleared, the front panel (not shown) of the copying machine body is opened and the unit body is pulled out to the front side.

However, when the first means is employed, the unit must be lowered by a large amount in order to secure a space necessary for jam clearance. Therefore, the height of the copying machine itself is increased, and unnecessary space is not required during a normal copying operation.

According to the second means, the paper jammed in the unit can be removed by pulling the unit out to the front and then coming out of the unit. In the configuration using the transfer belt as the transfer unit, the attraction force of the transfer belt to the sheet remains for a while even after the copying operation is stopped.

Therefore, when the unit is pulled out, the jammed paper comes out in a state of being attached to the transfer belt. If the pressure of the registration roller pair is not released at this time, the paper may be torn or the registration paper may be removed after the unit is pulled out. It becomes difficult to pull out the paper from between the roller pairs.

For this reason, when the unit body is pulled out, the pressure of the registration roller pair needs to be released. Although not particularly shown, the above means includes a handle for releasing pressure,
It is necessary to provide a pressure release mechanism connected to this handle, which has poor workability and has a complicated mechanism and has an adverse effect on cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to link the release of the pressurization of the alignment paper feeding means with the pull-out operation of the unit body.
An object of the present invention is to provide an image forming apparatus capable of reducing a user's work labor at the time of jam clearance, having a simpler configuration, having a stable pressing force, and not affecting image quality.

[0014]

In order to satisfy the above-mentioned object, an image forming apparatus according to the present invention includes an apparatus main body having an image carrier on which an electrostatic latent image is formed on a peripheral surface, and an image forming apparatus disposed inside the apparatus main body. A positioning sheet feeding unit for positioning the sheet fed to the image carrier at a position immediately before the image carrier and feeding the sheet in time with the electrostatic latent image, and detachably attached to the apparatus main body. A unit body provided with a transfer unit for transferring at least an electrostatic latent image formed on the image carrier onto a sheet, and a lower component of the image carrier integrated with the unit body; A paper jam releasing means provided between the paper means and the unit body, wherein the paper jammed in the alignment paper feeding means is freely released in conjunction with the drawing of the unit body from the apparatus main body.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an entire electronic copying machine as an image forming apparatus. In the main body H of the copying machine, a photosensitive drum 7 as an image carrier which is driven to rotate at the center thereof is arranged, and a charging charger 8 and a developing device 9 are arranged around the photosensitive drum 7 along the rotating direction. , A transfer unit 10, a cleaning device 11, and a discharge lamp 12 are sequentially arranged.

At the bottom of the copying machine main body H, there are arranged a plurality of cassettes 13 for accommodating sheets of different sizes. The pickup roller 14 rolls on the uppermost sheet in the cassette 13 and forms a sheet feeder 15.

An automatic double-sided paper feeder (also referred to as ADD) is provided further above the uppermost cassette of the paper feeder 15.
16 are arranged. And, these automatic two-sided paper passing devices 1
6 and the side of the paper feeder 15, a large capacity paper feeder (LCF
17) is also arranged.

The paper feeder 15 and the automatic duplex paper feeder 1
6 and a paper feed path 19 are provided on the paper feed side of the large-capacity paper feed device 17, respectively, and the paper fed from each device is arranged at the lower side of the developing device 9. To the pair of registration rollers 20.

The transfer unit 10 is arranged on the sheet discharge side of the pair of registration rollers 20. A transport belt 21 for transporting a sheet is provided at a side portion of the transfer unit 10.
The fixing device 22 is disposed at the transport end of the transport belt 21.

A paper discharge unit 23 comprising a pair of paper discharge rollers is provided on the side of the copying machine main body H on the side of the fixing device 22, and a paper discharge unit is provided outside the copier main body H facing the paper discharge unit 23. A tray is attached.

In the electronic copying machine thus constructed, the transfer unit 10, the transport belt 21, the fixing device 22, and the like, which are the components under the photosensitive drum 7, are all integrated into one unit, and are represented by cross hatching in the figure. Unit body Y
Is configured as

The unit body Y is fitted into a rail laid in the copier main body H in the front-rear direction, and by opening a front door (not shown) of the main body, the unit body Y is viewed from the front side of the copier main body H. It is removable.

As shown in FIGS. 2 to 5, a pressure releasing mechanism K is provided between the unit body Y and the registration roller pair 20 as a paper jam releasing means described later. FIGS. 2 and 4 show a state where the registration roller pair 20 is pressed by the pressure release mechanism K in a state where the unit body Y is mounted at a predetermined position. FIGS. 3 and 5 show the unit body Y.
7 shows a state in which the registration roller pair 20 is released from the pressure by the pressure releasing mechanism K in a state where the roller is pulled out.

The details of the registration roller pair 20 and the pressure release mechanism K will be described below with reference to FIG. The support shaft 30 of the upper registration roller 20A, which is one of the registration roller pairs 20, is connected to a front frame Hf constituting the copier main body H.
And the rear frame Hr.

The lower registration roller 20B, which is the other, is incorporated in a registration unit Ry, which is a rotating body.
It is elastically supported on one side end of a frame 32 constituting y via a roller pressing coil spring 33 which is a roller elastic support.

The registration unit Ry is supported by the front and rear frames Hf and Hr via a fulcrum 34 provided at the other end, and is pivotally supported about the fulcrum 34. .

On the upper side of the registration unit Ry, a paper transport guide 35 for positioning is provided, and on the upper end edge of the registration unit frame 32 facing the guide 35, a projection 32a is provided integrally.

A pressure bracket 36 is provided below the resist unit Ry. The pressurizing bracket 36 is mounted on the front and rear frames H in the FR direction.
It is slidably supported so as to face f and Hr.

The pressing bracket 36 includes a bracket 37 provided on the copying machine main body H and the pressing bracket 3.
6 is always pulled to the front side, which is the F direction, by a spring 38 hung between the bracket 36a provided on the front side.

When the unit Y is accommodated in the copying machine main body H, the auxiliary bracket 40 provided on the rear side of the unit Y is connected to the pressing bracket 36 shown in FIG.
Thus, the pressing bracket 36 moves toward the rear side, which is the R direction, against the elastic force of the spring 38.

When the pressing bracket 36 moves in the R direction, a pair of rollers 41, 41, which are contact portions provided on both side ends of the pressing bracket 36, are turned into a pair of elastic members provided on the bottom of the registration unit Ry. Leaf spring 4
Push up 2,42.

The leaf spring 42 projects obliquely downward from the registration unit Ry.
This elastic repulsive force is applied upward in the U direction by contacting the second projecting piece.

Therefore, the registration unit Ry is pushed up about the fulcrum 34, and the lower registration roller 20B elastically supported by this unit presses the upper registration roller 20A pivotally supported by the copying machine main body H. It comes into contact with the state.

In this pressurized state, the resist unit Ry
It is positioned by being brought into contact with the guide 35 via the projection 32a. The actual load between the rollers 20A and 20B is determined by the deflection of the roller pressing coil spring 33 at this position.

The leaf spring 42 is necessary to absorb variations in parts dimensions and mounting, and the load of the leaf spring 42 is, of course, applied to the upper and lower registration rollers 20A, 20B.
Must be greater than the load between them.

The pressing force between the upper and lower registration rollers 20A and 20B is reduced by the leaf spring 42 to the pressing coil spring 33.
It is determined only by the above, and a stable pressing force which is not affected by parts or assembly can be obtained.

At this time, the leaf spring 42 is
In order to accurately position by pushing up y, (pressing force of leaf spring 42)> (upper and lower registration rollers 20)
The pressure must be designed to be (A, 20B) + (the weight of the resist unit Ry).

Actually, the pressing force of the electronic copying machine to which this method is applied is the pressing force of the leaf spring 42 = 5400 g, and the pressing force between the upper and lower registration rollers 20A and 20B = 2.
500 g (all on one side).

Since the pressing force between the upper and lower registration rollers 20A and 20B is very strong, if the unit body Y receives a reaction force of the registration roller pressing force, there is a risk that the image quality may be affected. According to this type of configuration, the unit body Y is connected to the front F
The unit Y only moves horizontally in the direction of the rear R, and the unit Y does not directly receive the force of the upper and lower registration rollers 20A and 20B, so there is no danger of affecting the image quality.

FIGS. 3 and 5 show a state in which the pressure is released. When the unit body Y is pulled out from the copying machine main body H, the pressed state of the unit body Y against the pressing bracket 36 is released. Since the pressing bracket 36 is always pulled in the F direction, when the pressing is released, the bracket 36 smoothly moves in the F direction (the state shown in the figure).

When the pressing bracket 36 moves in the F direction, the roller 41 mounted on the pressing bracket 36 rolls to release the pressing against the leaf spring 42, and the registration unit Ry is reversed in the U direction. In the direction D.

That is, the lower registration roller 20B pivotally supported by the registration unit Ry is connected to the upper registration roller 20A.
And the pressurized state is released. In addition,
The roller 41 provided on the pressing bracket 36 includes:
The bracket 36 rotates with the movement of the bracket 36. However, the present invention is not limited to this, and any configuration may be used as long as frictional resistance is not generated as much as possible with the leaf spring 42. For example, a plastic material fixed to the pressing bracket 36 may be used.

FIG. 6 shows a second embodiment of the present invention. The upper registration roller 20A is still pivotally supported by the copying machine main body H, and the registration unit Ry that pivotally supports the lower registration roller 20B is the same as that described above except that a bristle brush 50 is newly provided. Since they are completely the same, the same numbers are given here and a new description is omitted.

The tip of the bristle brush 50 is in contact with the lower registration roller 20B.
Is wiped with the rotation of the roller. Therefore, even if paper dust is generated from the paper that is aligned and conveyed by the rotation of the upper and lower registration rollers 20A and 20B, it is removed without adhering to the peripheral surfaces of the respective registration rollers.

The unit body Ya used here is a pair of operating portions which are provided at the front and rear end portions of the upper surface thereof and are capable of coming in contact with and separating from a pair of leaf springs 42 provided on the bottom of the registration unit Ry. The operation projections 51, 51 are provided integrally. Therefore, the pressurizing bracket 36 described above does not exist here.

The contact position between the operation projection 51 and the leaf spring 42 is set with a phase difference between the front side and the rear side. Therefore, when the unit body Y is pulled out and inserted from the copier main body H, the front and rear operation projections 51 and the leaf springs 42 do not interfere with each other.

In the drawing, reference numeral 52 denotes a stopper. As shown in FIG. 6A, there is no action when the upper and lower registration rollers 20A and 20B press the operating projection 51 of the unit body Ya against the leaf spring 42. Not done.

As shown in FIG. 6B, when the unit body Ya is pulled out when the pressure is released, and the lower registration roller 20B is separated from the upper registration roller 20A, the registration unit Ry descends and rests on the stopper 52. .

That is, although the stopper 52 is provided for supporting the registration unit Ry, it is detachable from the copier main body H. As shown in FIG. 6C, by taking out the stopper 52 from the copying machine main body H as needed from the state in which the registration unit Ry is supported, the registration unit Ry is suspended from the fulcrum portion 34.

Accordingly, a large space is formed between the upper registration roller 20A and the lower registration roller 20B, and the upper and lower registration rollers 20A, 20A,
The cleaning operation for the 20B and the replacement operation of the paper dust removing bristle brush 50 can be easily performed.

[0051]

As described above, according to the present invention, when a sheet is jammed in the registration roller pair as the alignment sheet feeding means and its periphery, the unit body is pulled out to interlock with this operation. Pressurization of the registration roller pair is released, thereby reducing the user's labor during jam clearance and improving operability.

Further, the structure is simpler than using a handle for releasing the pressure of the registration roller, and a stable pressing force can be obtained with a small number of parts, thereby improving the reliability without affecting the image quality. It has effects such as being performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electronic copying machine according to an embodiment of the present invention.

FIG. 2 is a side view of the registration roller pair and a pressure release mechanism during pressurization according to the first embodiment.

FIG. 3 is a side view of the registration roller pair and the pressure release mechanism when the pressure is released according to the embodiment;

FIG. 4 is a front view of the registration roller pair and the pressure release mechanism when pressure is applied according to the embodiment;

FIG. 5 is a front view of the registration roller pair and the pressure release mechanism when the pressure is released according to the embodiment;

FIG. 6 is a front view of a pair of registration rollers and a pressure releasing mechanism according to a second embodiment when pressure is applied and when pressure is released;

[Explanation of symbols]

 7: Photoconductor drum (image carrier), H: Copy machine main body (apparatus main body), 20: Registration roller pair (alignment feeding means), 20A: Upper registration roller, 20B: Lower registration roller, Y, Ya ... Unit body, K: pressure release mechanism (paper jam removal means), Ry: registration unit (rotating lever), 42: leaf spring (elastic body), 41: roller (contact / separation part), 36: pressure bracket, 51: Projection for operation (operation part), 33: Coil spring for roller pressing (roller elastic support), 35: Guide for positioning, 50: Bristle brush

Claims (1)

[Claims] 1. An apparatus main body having an image carrier on which an electrostatic latent image is formed on a peripheral surface, and a sheet disposed in the apparatus main body and fed to the image carrier is positioned immediately before the image carrier. A positioning paper feeding means for positioning and feeding the electrostatic latent image at the same time as the electrostatic latent image, and an electrostatic latent image formed on the image carrier at least detachably provided on the apparatus main body, A unit body having a transfer unit for transferring and integrating the lower component parts of the image carrier; and a unit body provided between the unit body and the alignment sheet feeding unit;
An image forming apparatus, comprising: a paper jam clearing means for freely releasing paper jammed in the alignment paper feeding means in conjunction with pulling out of the unit body from the apparatus main body.