JPH1048917A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device, in which an upper unit and a lower unit can be dividable so as to be opened or closed making the boundary of a paper conveying passage, by which the distance between an image carrier and an electrification means can be always kept in a prescribed value without damaging the image carrier with a relatively simple constitution, and also by which stable electrification can be always carried out. SOLUTION: An electrification device 30 is energized upwards, and is supported so as to be movable in the vertical direction while being restrained in the right and left movement; and when an upper unit 26 is closed, a part of the upper unit 26 is brought into contact with the electrification device 30, so that the electrification device 30 is positioned to have a prescribed distance with the image carrier that has been held by the upper unit 26. When the upper unit 26 is opened, the upward movement of the electrification device 30 beyond the movable range is restrained by a second restraining means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electronic copying machine and an electronic printer, and more particularly, to an image forming apparatus having an improved positioning structure of a corona discharger for charging an image carrier.

[0002]

2. Description of the Related Art Generally, in a copying machine in which a photoreceptor such as selenium or CdS drum is used as an image carrier, a copying machine, a transfer machine, a paper peeling device, and a static eliminator are provided in close proximity to the photoreceptor. Charging means including a corona discharger is provided.

On the other hand, in recent years, in order to facilitate the work of removing paper jams around the photoconductor, the periphery of the photoconductor has
Many copiers have been put to practical use in which any of these corona dischargers is detached and, after the work is completed, can be returned to a predetermined position again. As one of them, the copier is divided into two parts vertically around the paper transport path, a photoreceptor is placed on the upper unit side, a transfer machine is placed on the lower unit side, and a corona discharger is used as a peeler. In some cases, the distance between the photoconductor and the corona discharger can be widened by rotating and displacing the upper unit.

However, conventionally, the positioning of the photoconductor and the corona discharger is performed by abutting the frames of the respective units to which these are mounted. Therefore, the relative position accuracy between the photoconductor and the corona discharger varies due to variations in manufacturing and assembling, and the relative position of the corona discharger with respect to the photoconductor changes due to disorder due to repeated opening and closing of the upper unit. Therefore, there was a problem that stable corona discharge could not be performed and transfer failure and peeling failure occurred.

[0005]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above circumstances, and has as its object to roughly divide the upper unit into two lower units with a paper transport path as a boundary, and to provide one unit with an image. In an image forming apparatus in which an image carrier having a carrier support shaft as a center of rotation is provided and a corona discharger is disposed in the other unit, the image carrier and the corona discharger are relatively simple in configuration. An object of the present invention is to provide an image forming apparatus which can always maintain a predetermined value without damaging an image carrier and can always perform a stable charging operation.

[0006]

That is, in order to solve the above-mentioned problems, the present invention provides a first unit, a transport unit provided in the first unit, for transporting a sheet, and a sheet transport by the transport unit. A second unit provided to be openable and closable with respect to the first unit with a road as a boundary, and an opening and closing operation of the second unit with respect to the first unit integrally attached to the second unit And an image carrier that moves along with the first unit. When the second unit is closed with respect to the first unit, the image carrier is opposed to the image carrier. A charger provided at a position exposed to the outside when opened to the first unit; and a charger provided at the first unit side, wherein the second unit is opened to the first unit. That has been Supporting the charger so that it can be inserted into and removed from the space formed by the second unit and the first unit in a direction in which the image carrier moves, and guiding the charger so as to be movable. A biasing member provided on the first unit side for biasing the charger so as to be movable toward and away from the image carrier; and a biasing member provided on the second unit side. And fixedly supports the image carrier, and when the second unit is closed with respect to the first unit,
A first regulating member that regulates the position of the charger so that the distance between the charger and the image carrier is constant by contacting a part of the charger; And when the second unit is opened to the first unit, the image carrier direction of the charger supported by the support means and urged by the urging member Is limited to within a predetermined amount by engaging both ends of the charger, and when the charger is not supported by the support means, the second unit and the first unit are not supported. And a second restricting member that allows the charger to move in the direction of the supporting means from the space formed by the above.

According to the above means of the present invention, when the second unit is closed with respect to the first unit, the distance between the charger and the image carrier automatically becomes constant,
A stable charging operation is always possible, and good image formation is possible.

The second unit to which the image bearing member is attached is opened to the first unit with the paper transport path as a boundary, so that the charger provided on the first unit side can be used as a charging unit. Since it is exposed to the space formed between the second unit and the first unit, the charger can be inserted and removed using the space. Therefore, it is not necessary to secure a dedicated space for inserting and removing the charger in advance, and the structure is simple and inexpensive because there is no need for a drawer mechanism for exposing the charger to the outside.

Further, since the moving direction of the image carrier when the second unit is opened with respect to the first unit and the inserting / removing direction of the charger are the same, the operation of inserting / removing the charger is performed. Can be easily performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a configuration of an electronic copying machine as an image forming apparatus. In FIG. 1, reference numeral 1 denotes a main body of the copying machine. A document table 2 is installed on the upper surface of the main body 1, and is configured to be able to reciprocate in the direction of arrow X as required. A detachable tray 3 is provided on the left side of the main body 1.
On the right side, a cassette 4 containing copy paper P and a manual feed guide 5 are provided.

A drum-shaped photosensitive member 6 as an image carrier is provided at a substantially central portion in the main body 1, and a charger 7, an exposure device 8, a developing device 9, a transfer device 10 ,
A peeler 11, a static eliminator 12, a cleaning device 13, and an afterimage erasing device 14 are sequentially arranged along the rotation direction. The exposure device 8 has an illumination system 8a for illuminating a document (not shown) placed on the document table 2 and a convergent light transmitting body 8b for guiding light reflected from the document to the photoconductor 6. .

A paper feed mechanism 15, 1 is provided on the right side inside the main body 1.
A copy paper 6 is provided, and the copy paper P in the cassette 4 and the copy paper manually inserted through the manual guide 5 are fed into the paper transport path 17. The paper transport path 17 includes a transport roller pair 18 and the transport belt 1.
9, a conveying means composed of a pair of paper discharge rollers 20, etc., and guide plates 21 appropriately arranged between them, and the like, and an intermediate portion thereof passes through a transfer portion between the photoconductor 6 and the transfer device 10. It has become. Further, a fixing roller pair 22 is disposed at the end of the sheet transport path 17.

The document table 2 is located on the upper right side of the main body 1.
Movement and the motor 23 as a rotation drive source of the photoreceptor 6
Further, cooling devices 24 for preventing an abnormal temperature rise of the heat generating portion in the main body 1 are provided at an upper left portion in the main body 1, respectively. Reference numeral 25 denotes a paper discharge detection switch provided near the paper discharge roller pair 20 of the paper transport path 17.

When the copy button (not shown) is pressed, the photosensitive member 6 starts to rotate clockwise in the drawing, and the document table 2 moves forward in synchronization with this movement, and the photosensitive member 6
Charger 7, exposure device 8, developing device 9 arranged around
A developer image corresponding to the document table is formed on the photoreceptor 6 with the above operation.

Further, in synchronization with the operation of forming the developer image, the copy paper P is fed to the transfer section, and the developer image is transferred to the copy paper P by the operation of the transfer device 10. The copy paper P is moved to the photosensitive member 6 by the function.
And is conveyed to the tray 3 via the paper conveyance path 17. Then, during this conveyance, the fixing roller pair 22 fixes the developer image.

On the other hand, the photosensitive member 6 after the transfer of the developer image
The surface of is clean by sequentially facing the static eliminator 12, the cleaning device 13, and the afterimage elimination device 14, and again faces the charger 7.

During this time, the document table 2 moves forward and returns to the original position, and one copy operation is completed. The copying machine thus constructed is vertically divided into two parts by a line L substantially along the paper transport path 17, and the upper unit 26, which is the second unit, is rotated upward by an angle θ if necessary. The lower unit 28, which is the first unit, can be separated. If the copy paper P is jammed in the paper transport path 17 for some reason, most of the paper transport path 17 can be released and the jammed copy paper P can be easily removed.
Can be removed.

The photoreceptor 6 is provided on the frames 27, 27 on the upper unit 26 side, and the transfer unit 10 and the peeling unit 11 are provided on the frames 29, 29 on the lower unit 28 side. As a result, the relative positions of the photoconductor 6, the transfer device 10, and the peeling device 11 change. However, in the present invention, the transfer unit 10 and the peeling unit 11 are formed by the first and second corona discharge portions of the corona discharge device 30 which is a charger described later, so that the upper unit 2 is formed.
When the unit 6 is superimposed on the lower unit 28, the distance between the photoconductor 6 and the transfer unit 10 and the separation unit 11 is always maintained at a predetermined value.

Next, the corona discharge device 30 will be described with reference to FIGS. In the figure, 31 is a discharger body,
The discharger body 31 has two shield cases 32, 3
2 and these shield cases 3
Discharge wires 33, 33 are stretched inside the first and second corona discharge portions of the transfer device 10 and the peeling device 1.
Corona discharger 3 having second corona discharge section as 1
4.

Further, support projections 3 as support means are provided on the lower surfaces of both ends of the discharger main body 31 of the corona discharger 34.
5, 35 are formed, and are fitted into recesses of support members 36, 36 as fixing portions screwed to the frames 29, 29 of the lower unit 28, and biasing fits into these recesses. It is elastically supported by coil springs (elastic support members) 37 as means. The corona discharger 34 is swingable in a direction to contact and separate from the photoreceptor 6 and is always urged toward the photoreceptor 6.

At the four corners on the upper surface on both sides of the discharger main body 31, support arms 38 are respectively provided to protrude. Guide rollers (first positioning portions) are provided on the upper end surfaces of these support arms 38.
39 are rotatably supported. When the upper unit 26 is superimposed on the lower unit 28, the photosensitive members 6 attached to the frames 27
The non-image forming portions (second positioning portions) 6a, 6a of both ends and the guide rollers 39 are in rolling contact with each other, and the transfer device 10, the peeling device 1
The corona discharger 34 having the first and second corona discharge portions as 1 is positioned.

If the mounting positions of the guide rollers 39 with respect to the discharger main body 31 are set to predetermined values, the surface of the photoconductor 6 and the first and second transfer units 10 and 11 are removed.
The interval between the discharge wires 33 of the second corona discharge portion is always kept constant, and extremely stable corona discharge performance can be obtained.

The guide rollers 39 are arranged on the photosensitive member 6.
, And a high voltage is appropriately applied to the discharge wires 33, 33 from a high-voltage power supply unit (not shown) via a flexible power supply line.

Further, the present invention is not limited to the above-described embodiment.
As shown in FIG. 13, various modified embodiments are possible.
That is, as shown in FIG. 4, the micrometer mechanisms 40 are respectively attached to the support arms 38 to which the guide rollers 39 are attached.
The distance between the discharge wire 33 and the photoconductor 6 at the position of each roller 39... Can be arbitrarily adjusted, so that the corona discharge can be adjusted extremely easily. It should be noted that the same object can be achieved even with a simple screw mechanism instead of the micrometer mechanism 40.

Also, as shown in FIG.
May be determined not by the surface of the photoconductor 6 but by the photoconductor support shaft (support portion) 41. With this configuration, the guide rollers 39 are not required, and the surface of the photoconductor 6 is not damaged.

A photosensitive member support shaft (contact portion) 41
It is desirable that the shaft contact portions (positioning portions) 42a, 42a of the support pieces 42, 42 that come into contact with the shaft are made of a self-lubricating resin or the like. Also, the shaft contact portions 42a, 42a
Are formed with inclined surfaces 43 along the shaft insertion direction so that the shaft 41 can be inserted smoothly even when the shaft 41 is inserted while sliding.

The support members 44, 44 of the floating corona discharger 34 are attached to the frames 29, 29 integral with the lower surface base 45 of the copying machine body 1 by hooking the hooks 44a, 44a. You may.

Further, as shown in FIG. 6, the support pieces (positioning portions) 46, 46 are positioned by contacting the frames (contact portions) 27, 27 of the upper unit 26 to which the photosensitive member 6 is attached. You may.

A coil spring 3 as an elastic support member
One of the electrodes 7 and 37 is formed of a conductive material, and one end thereof is connected to one terminal 48 for applying a voltage to a discharge wire 33 stretched through terminals 47 and 48, and the other end is connected to a high-voltage power supply. The voltage may be applied to the discharge wire 33 by being pressed against the power supply portion 49a of the power supply 49. In this case, there is no early damage or the like due to repeated bending of the power supply line, which would occur when the discharge wire 33 and the power supply 49 are connected via a flexible power supply line, and the number of components can be reduced.

Further, a coil spring 3 as an elastic support member
The engaging recesses 5 are provided on both side surfaces of the discharger main body 31 of the corona discharger 34 which is constantly urged toward the photoreceptor 6 by the first and third photosensitive members 7 and 37.
0, 50 are formed, and the locking claws 51a, 51a, of the locking arms 51, 51 extended from the power supply 49 and the support member 44, respectively.
The amount of movement of the corona discharger 34 may be restricted by engaging the 51a to prevent the corona discharger 34 from falling off.

By forming the locking arms 51, 51 from an elastic synthetic resin or the like, the locking arms 51 can be easily assembled simply by opening the locking arms 51 elastically and inserting the corona discharger 34. In addition, not only the vertical movement of the corona discharger 34 but also the horizontal direction may be controlled at the same time.

The power supply 49 produces a necessary high voltage from a DC power supply by a known method. Further, the elastic support member also serving as the power supply member is formed of a conductive coil spring, but is not limited thereto. For example, as shown in FIG.
And the upper unit 26 comprising the charger-side power receiver 53.
The contact portion 5 is superposed on the lower unit 28 in a state where
The 2a and 52b may be pressed against each other.

Further, as shown in FIG.
The contact portions 52a and 53a between the battery and the charger-side power receiving body 53 are inclined so that they are in sliding contact with each other at the time of press contact, and the contact portions 52a and 53a are cleaned each time the contact is made, thereby preventing poor contact. You may make it.

9 and FIG. 10 taken along the line XX of FIG. That is, 5
Reference numeral 4 denotes a support member for supporting the corona discharger 34, in which a power supply 49 is incorporated, and a voltage generated from the power supply 49 is transmitted to a power supply side power supply 52.

The support member 54 is formed of an elastic resin or the like, and has locking arms 55 and 56 formed at both ends thereof. The locking claws 55 of the lower locking arms 55 and 55 are provided.
The support member 54 is fixed to the frames 47, 47 by engaging the a, 55a with engagement holes 57, 57 formed in the frames 29, 29 integral with the lower surface base 45 of the copying machine body 1.

A corona discharger 34 is provided between the upper locking arms 56, 56, and the respective locking claws 56a, 5a.
The vertical movement and the horizontal movement are regulated by the engagement of the engagement recesses 50, 50 formed on the outer surfaces of the support pieces 46, 46 with the 6a.

Further, as shown in FIG.
Stopper members 58, 58 are integrally formed at both ends of the, respectively, so as to regulate the movement of the corona discharger 34 in the left-right direction in FIG.

The portions corresponding to the engagement recesses 50 on the lower surfaces of both ends of the discharger main body 31 are sloped portions 59, 5 like the sloped portions of the locking claws 56a, 56a of the locking arms 56, 56.
9 are formed so that the discharger main body 31 can be incorporated into the support member 54 with one touch.

After the corona discharger 34 has been assembled, the repulsion force at the time of contact between the power supply side power supply 52 formed of a conductive leaf spring and the charger side power receiver 53 and the lower surface of the discharger body 31 are formed. The locking arms 56a, 56a of the locking arms 56, 56, which are pushed up by the repulsive force at the time of contact between the elastic pieces 60, 60 and the support member 54, and the engagement recesses 50, 50 Does not cause the corona discharger 34 to fall off.

It should be noted that the elastic pieces 60, 60 are
May be formed integrally with a resin, or may be formed and attached as a separate member, or may be attached to the support member 54 side instead of the discharger main body 31 side.

When the upper unit 26 is closed, the frames 27, 27 descend and come into contact with the upper surfaces of the positioning members 46, 46 of the discharge main body 31 to be pushed down. Thereby, the positional relationship between the corona discharger 34 and the frames 27, 27 is determined.

The relative positions of the frames 27, 27 and the photoreceptor 6 are determined in advance, and the height of the discharge wire 33 between the terminals 48 and 47 is determined by a height determining member (an eccentric screw (not shown), The distance between the photoconductor 6 and the discharge wire 33 is kept constant because the distance is adjusted by the adjustment mechanism 61 (including an adjustment mechanism).

Also, as shown in FIG.
The discharger main body 31 and the supporting member 54 may be integrated into a unit. Then, elastic unit support members 63, 63 are formed at both ends of the discharge unit 62, and the distal end portions thereof are engaged with locking holes 64, 64 formed in the frames 29, 29, so that the discharge unit 62 is formed. 62
May be elastically supported.

The discharge unit 62 may be formed by integrally forming the discharger main body 31 and the support member 54, or may be made of an optimal material as needed. As described above, if the same unit is provided with the corona discharger 34, the power supply 49, and the unit support member 63, not only can the unit be easily adjusted, but also it is easy to assemble and attach. It has the effect of greatly reducing. Further, it is possible to eliminate a contact through which a high voltage passes.

In the description of the other embodiment, the same parts as those of the above-described embodiment and the preceding embodiments are denoted by the same reference numerals, and the description thereof will be omitted. In addition, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0046]

As described above, according to the present invention, when the second unit is closed with respect to the first unit, the distance between the charger and the image carrier automatically becomes constant.
A stable charging action is possible, and good image formation is possible.

Further, by opening the second unit to which the image carrier is attached with respect to the first unit with the paper conveyance path as a boundary, the charging unit provided on the first unit side becomes the second unit. Since it is exposed to the space formed between the second unit and the first unit, the charger can be inserted and removed using the space. Therefore, it is not necessary to secure a dedicated space for inserting and removing the charger in advance, and a simple and inexpensive structure can be achieved without requiring a drawer mechanism for exposing the charger to the outside.

Further, since the moving direction of the image carrier when the second unit is opened with respect to the first unit and the inserting / removing direction of the charger are the same, the operation of inserting / removing the charger is performed. Is easily achieved.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional front view of a copying machine in which one embodiment of the present invention is applied to a transfer device and a peeling device.

FIG. 2 is a schematic vertical cross-sectional side view of the main part.

FIG. 3 is a schematic longitudinal sectional front view of the same.

FIG. 4 is a perspective view showing a modified example of a positioning member capable of arbitrarily changing the position of a guide roller.

FIG. 5 is a schematic vertical sectional front view showing an example of positioning according to a photoreceptor shaft, showing a first other embodiment of the present invention.

FIG. 6 is a schematic vertical sectional front view showing an example of positioning according to a frame on which a photoreceptor is mounted according to a second other embodiment of the present invention.

FIG. 7 is an exploded perspective view showing a modification of a power supply portion.

FIG. 8 is a cross-sectional view showing an improved contact portion of a power supply portion.

FIG. 9 is a schematic longitudinal sectional front view showing an example in which a high-voltage power supply unit is built in a support member according to a third embodiment of the present invention.

FIG. 10 is a sectional view taken along the line XX in FIG. 9;

FIG. 11 is a schematic longitudinal sectional front view showing an example in which a discharger body and a support member are integrated with each other, showing a fourth other embodiment of the present invention.

[Explanation of symbols]

6 image carrier (photoreceptor), 17 paper transport path, 18, 1
9, 20: conveying means, 26: second unit (upper unit), 27: first regulating member, 28: first unit (lower unit), 30 (10, 11): charger (corona discharge device) ), 55, 56, 58 ... support means, 52, 5
3, 60 ... urging means, 56 ... second regulating member

Claims (1)

[Claims] A first unit, a transport unit provided in the first unit for transporting a sheet, and openable and closable with respect to the first unit across a paper transport path of the transport unit. A second unit provided; an image carrier that is integrally attached to the second unit and moves in accordance with an opening / closing operation of the second unit with respect to the first unit; And the second unit is opposed to the image carrier when the second unit is closed with respect to the first unit, and is exposed to the outside when the second unit is opened with respect to the first unit. A charger provided at a position, wherein the second unit and the first unit are provided on the first unit side and the second unit is open to the first unit. And by Support means for supporting the charger so that it can be inserted into and removed from the space formed by the image carrier, and for guiding the charger movably; provided on the first unit side; An urging member that movably urges the charging device in a direction in which the charger is moved toward and away from the image carrier; and an image carrier that is provided on the second unit side and fixedly supports the image carrier. When the second unit is closed with respect to the first unit, by contacting a part of the charger, the distance between the charger and the image carrier is kept constant. A first regulating member that regulates the position of the charging device; and a first regulating member that is provided on the first unit side and is supported by the support unit when the second unit is open to the first unit. And biased by the biasing member. The movement of the charger in the direction of the image carrier is restricted to a predetermined amount by engaging both ends of the charger, and when the charger is not supported by the support means, , The second unit and the first
And a second restricting member that allows the charger to move in the direction of the support means from the space formed by the unit.