JPH0727316B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention includes an image forming apparatus, and more specifically, includes means for uniformly charging the surface of an image carrier which is rotated or rotationally driven to move the surface of the image carrier. The present invention relates to an image forming apparatus of a system in which an image forming process unit is applied to execute image formation, and an image carrier surface subjected to image formation is cleaned by a cleaning unit and repeatedly subjected to image formation.

[Conventional technology]

Specific examples of the above-described image forming apparatus include a transfer type electrophotographic copying apparatus and a transfer type electrostatic recording apparatus.

A transfer type electrophotographic copying apparatus uses a drum type or endless belt type electrophotographic photosensitive member that is rotated or rotationally driven as an image carrier, and basically performs uniform charging, image exposure, and development on the photosensitive member surface. The image forming process means is applied to form a visible image, the visible image is transferred to the transfer material surface by the transfer means, and the transfer right image is fixed to the transfer material surface by the fixing means. To output. After the image transfer, the surface of the photoreceptor is cleaned by a cleaning means and repeatedly used for image formation.

A transfer type electrostatic recording device uses a drum-type or endless belt-type dielectric that is rotated or driven to rotate as an image bearing member, and basically performs uniform charging, selective charge removal, and development on the dielectric surface. An image processing means is applied to form a developed image, and thereafter, the developed image is transferred and fixed on the surface of the transfer material in the same manner as in the electrophotographic copying apparatus, and the transfer material is output as an image-formed product. The dielectric surface after transfer is cleaned by a cleaning means and repeatedly used for image formation.

The cleaning unit removes untransferred residual developer (toner), transfer material paper dust, and other adhered contaminants remaining on the surface of the photoconductor or the dielectric as an image carrier after the image transfer onto the transfer material surface. In general, a rubber elastic member such as urethane rubber is used, and the member is brought into contact with the surface of the image carrier to wipe off the contaminants attached to the surface of the image carrier.

A corona discharger such as a corotron or a scorotron, which has a good uniform charging property, is widely used as a means for uniformly charging the surface of a photoreceptor or a dielectric as an image carrier. However, the corona discharger requires an expensive high-voltage power source, requires a space such as itself and a shield space for the high-voltage power source, and corona products such as ozone are often generated, and additional means / mechanisms for coping with this are required. There is a problem in that it is necessary, and these are factors that increase the size and cost of the device.

Therefore, in recent years, the adoption of the contact charging method has been considered instead of the corona discharger, which has many problems. The contact charging is a conductive member (contact charging member) in which a voltage (for example, a DC voltage of about 1 to 2 KV, or a superimposed voltage of a DC voltage and an AC voltage) is applied by a power source to the surface of the image carrier serving as a member to be charged. By injecting a charge directly onto the surface of the image bearing member to bring the surface of the image bearing member to a predetermined electric potential by contact with the roller charging type (JP-A-56-91253) and blade charging type (JP-A-56- 19434
No. 9 and No. 60-147756), charging / cleaning combined type (JP-A-56-165166) and the like have been devised.

[Problems to be solved by the invention]

In the contact charging method, it is essential to apply the conductive member, which is a charging member, to the surface of the image bearing member, which is the member to be charged, uniformly in contact with each other along the length of the member. If the above is not obtained, uneven charging occurs on the surface of the image bearing member.

Further, in the case of the charging / cleaning combined type, uneven transfer may occur due to accumulation of transfer residual developer, transfer material paper powder, and other foreign matter wiped from the image carrier surface after image transfer. Particularly in the case of a process cartridge detachable type image forming apparatus, foreign matter may be mixed in the charging area due to vibration or the like that acts when attaching or detaching the process cartridge or carrying the process cartridge.

The present invention employs a contact charging system in which a charging member is brought into contact with the surface of the image carrier as the charging means of the image carrier.
In that case, the contact charging member with respect to the image carrier surface is set with high precision, that is, the contact charging member is uniformly and stably contacted with the image carrier surface at each portion along its length, The purpose is to uniformly charge the surface of the image carrier.

[Means for solving problems]

The present invention applies an image forming process means including a means for uniformly charging the surface of an image carrier, which is rotated or rotationally moved to move the surface, to perform image formation, and to provide an image for image formation. An image forming apparatus of a system in which a surface of a carrier is purified by a cleaning unit and repeatedly subjected to image formation, wherein the charging unit is a contact charging member which is brought into contact with the surface of the image carrier and a voltage is applied, The means is a cleaning member that is brought into contact with the surface of the image carrier, the contact charging member and the cleaning member share one supporting member, are positioned and fixedly supported by the supporting member, and both members are supported. The image forming apparatus is characterized in that at least the image carrier surface abutting portion is made of a different material from each other.

[Operation] Since the contact charging member and the cleaning member are fixedly supported by sharing one support member having the same setting standard, the contact charging member can be set in high-precision contact with the surface of the image carrier. That is, the contact charging member is set and held in a state in which the contact charging member uniformly and stably abuts on the surface of the image bearing member at each portion along the length thereof, and the uniform charging processability of the surface of the image bearing member by the contact charging member is secured.

Also, with respect to the cleaning member, a highly accurate contact setting with respect to the surface of the image bearing member is obtained, so that the cleaning effect is enhanced, and a clean image bearing member surface sufficiently cleaned by the cleaning member always moves to the contact charging member side. Therefore, the contact charging member is not contaminated by the foreign matter remaining after cleaning the surface of the image bearing member, and the uniform charging property of the surface of the image bearing member is more stably maintained in combination with the action of the above item.

Since the contact charging member and the cleaning member are not used as separate members but provided as separate members, there is no problem as described above when they are used as combined members. Further, the contact charging member and the cleaning member, which are separate members thereof, are made of different materials at least in the image carrier surface contact portion, that is, a material suitable for the function as the contact charging member and a material suitable for the function as the cleaning member. The contact charging effect and the cleaning effect can be individually optimized, and the uniform charging processability of the surface of the image bearing member can be well ensured in combination with the effects of the above items.

The charging unit and the cleaning unit are collectively and compactly arranged, that is, the process is arranged in a space-saving manner, and the size and weight of the apparatus can be reduced.

〔Example〕

FIG. 1 is a schematic diagram of the configuration of an apparatus according to one embodiment. This example is a process cartridge detachable transfer type electrophotographic copying apparatus.

In the figure, reference numeral 1 denotes a drum type electrophotographic photosensitive member (hereinafter abbreviated as photosensitive member) as an image bearing member which is rotationally driven around a support shaft 1a in a direction indicated by an arrow at a predetermined peripheral speed. 2 is a contact charging member as a means for uniformly charging the peripheral surface of the photosensitive member, 3
Is a short focus lens array as an optical image exposing means, 4 is a developing device, 5 is a transfer device, and 51 is a transfer material conveyed one by one from a paper feeding unit (not shown) in synchronization with the rotation of the photoconductor 1. A timing roller for feeding between the photoconductor 1 and the transfer device 5, 52
Is a transfer material guide member arranged between the timing roller 51 and the transfer device 5, and 52 is a fixing device (not shown) for the transfer material P which has passed between the photoconductor 1 and the transfer device 5 and has undergone image transfer. A feeding device 6 is a cleaning device for cleaning the surface of the photoreceptor 1 after the image transfer.

The apparatus of this example includes a photoconductor 1, a contact charging member 2, a developing device 4,
The four process devices of the cleaning device 6 are integrated into a process cartridge 7 having a predetermined positional relationship with each other, and are configured as a process cartridge 7. The process cartridge 7 is provided in a main body of the copying apparatus along support rails 8 and 8. It can be inserted and mounted as it is, and, on the contrary, it can be freely removed from the copying machine body.

By fully inserting the process cartridge 7 into the main body of the copying apparatus and mounting it therein, the main body of the copying apparatus and the side of the process cartridge 7 are mechanically and electrically coupled to each other to be operable as the copying apparatus.

The peripheral surface of the photosensitive member 1 is in contact with the contact charging member 2 during the rotation process.
Are sequentially uniformly charged by the above, and then sequentially passed through the position of the light image exposure means 3 to be subjected to the light image exposure L (slit exposure of the original image) to sequentially form electrostatic latent images corresponding to the exposure image pattern. Will be done. Reference numeral 7a denotes a contact charging member which is a light transmitting window hole opened in the wall portion of the cartridge housing corresponding to the light image exposing means 3. The optical image exposure L can also be performed by laser beam scanning. In the case of an electrostatic recording device, latent images are sequentially formed on the surface of the photoconductor by means of an electrode array or the like that selectively eliminates charge on the surface of the photoconductor.

The latent image formed on the surface of the photoconductor 1 is subsequently visualized (developed) as a toner image by the developing device 4, and the toner image on the photoconductor surface is transferred between the transfer device 5 and the photoconductor 1 by the transfer device 5. One sheet is conveyed from a sheet feeding unit (not shown), and is transferred onto the surface of the transfer material P fed by the timing roller 51 in synchronization with the rotation of the photoconductor 1.

The transfer material P, which has passed through the transfer device 5 and has undergone image transfer, is sequentially separated from the surface of the photosensitive member 1, introduced into a fixing device (not shown) by the conveying device 53, subjected to image fixing, and output as an image-formed product. It

On the other hand, the surface of the photoreceptor 1 after transfer is cleaned by a cleaning device 6 to remove untransferred toner, transfer material paper powder, and other adhering contaminants, and is cleaned to be repeatedly used for image formation.

FIG. 2A is a contact charging member 2 in the apparatus of FIG.
And a partially enlarged view of the cleaning member 61 portion of the cleaning device 6. Reference numeral 9 denotes a support for both the members 2 and 61, which is a conductive member such as a steel material or a mold. In the apparatus of this example, the contact position reference is set to the cleaning device container 62 for positioning the photoconductor 1 which is an image carrier. Determined tolerator 62
It is positioned and fixed to.

The cleaning member 61 is, in the case of this example, urethane rubber made of polyester or polyether (which may be liquid urethane or thermoplastic urethane), EPDM, an insulating rubber elastic blade such as NBR (cleaning blade),
It is firmly adhered and fixed to the support 9 with an adhesive 10 such as hot melt or epoxy.
a is in contact with the surface of the photosensitive member 1. The contact edge 61a of the cleaning blade 61 with respect to the surface of the photoreceptor 1 is 20 μm.
It is cut into smooth and sharp edges of m or less. The edge position is determined at the time of bonding or cutting with reference to the contact position reference between the cleaning device container 62 and the support 9.

In this example, the contact charging member 2 is a conductive rubber blade (contact charging blade) in which a rubber elastic body such as EPDM contains a conductive material such as carbon to reduce the resistance to 10 ¹⁰ Ω · cm or less.
It is firmly adhered and fixed to the support 9 with a conductive adhesive 11, and its lower side is in contact with the surface of the photoreceptor 1.
The contact portion 2a of the contact charging blade 2 with the surface of the photosensitive member 1 may or may not be an edge cut processing portion like the cleaning blade 61 described above, but the contact portion position is the same as the cleaning blade 61 described above. It is similarly positioned.

Reference numeral 12 is a voltage application power source for the contact charging blade 2.
The power source 12 is provided on the copying apparatus main body side, and the conductive support 9 on the process cartridge 7 side is provided in a state where the process cartridge 7 is inserted and mounted in the copying apparatus main body.
And is electrically connected.

Based on the copy start signal, a predetermined voltage is applied from the power source 12 to the contact charging blade 2 made of conductive rubber through the electric path 12a → the conductive support 9 → the conductive adhesive 11 to cause the rotary photosensitive member 1 to rotate. The peripheral surface is uniformly charged to a predetermined potential.

The adhesive 11 for adhering and fixing the contact charging blade 2 to the support 9 may be an insulating material 11a (Fig. 2 (B)). In this case, as in the example of Fig. 2 (B). Further, a conductive adhesive 11b or another conductive material for electrically connecting the conductive support 9 and the contact charging blade 2 is provided on a portion other than the adhesive portion. In the case of the conductive adhesive 11b, it also acts as a stopper for preventing the contact charging blade 2 from being displaced.

FIGS. 3A to 3D show, for example, the charging blade 2 and the cleaning blade 61, respectively, using the conductive support 9 as a common support in the same manner as in the above-described first and second examples. Although it is firmly fixed and supported by an adhesive agent 11 and 10, the shape of the support 9 and the blades 2 and 61, the mounting posture, and the contact mode with the surface of the photoconductor 1 are different. An example of an embodiment is shown.

For example, in the embodiment of FIG. 3 (A), the photoreceptor 1 as an image carrier is an OPC photoreceptor, the contact charging blade 2 is a blade made of conductive rubber such as EPDM, and the lower side of the blade is The surface of the photoconductor is brought into contact with the surface of the photoconductor by the elastic force of the deflection of the rubber blade itself in the range of linear pressure of 5 to 35 g / cm. A DC voltage for obtaining a predetermined charging potential is superposed on the contact charging blade 2 by a power supply (bias power supply) 12 via a conductive support 9 to a pulsating voltage having a peak-to-peak voltage which is more than twice the charging start voltage. By applying a voltage, the surface of the rotating photoconductor is uniformly contact-charged. In the range of the peripheral speed of rotation of the photoconductor 1 of 20 to 60 mm / sec, the power source 12 supplies the contact charging blade 2 with an AC component of 1500 Vpp and a frequency of 400 to 2000.
Applying a superimposed voltage of 700 V DC to Hz, and about 1
It was uniformly charged to 700V.

The cleaning member 61 is a member different from the contact charging member 2 and can be made of an optimum material as a cleaning member regardless of the contact charging member. For example, an insulating material such as urethane having a sharp edge with a high wiping effect can be used. By using a rubber blade, the cleaning property of the surface of the photosensitive member 1 is good, and the uniform charging property of the surface of the photosensitive member 1 by the contact charging member 2 is improved. In order to use the cleaning member 61 also as the contact charging member 2, for example, if a conductive material is added to the cleaning rubber blade to make it conductive, the strength and abrasion resistance of the rubber blade deteriorate, resulting in poor cleaning performance and uneven charging. Is easy to see.

The blade 2 as the contact charging member may be a film or the like. FIG. 4 (A) shows an example thereof. The contact charging blade 2 of this example is constructed by applying a film layer 2B of resin or rubber to a conductive sheet (or plate) 2A of metal or the like. is there. This film layer 2B has a thickness of 10 ¹² Ω
The voltage (AC component 1500VPP, frequency 400 to 2000Hz, DC component 700V) of the above example (Fig. 3 (A)) is applied to the conductive sheet 2A from the power source 12 through the conductive support 9 by setting the voltage to 0 µm or less. , The film layer 2B is brought into contact with the surface of the photoreceptor 1
When the contact charging of the surface was performed, the direct current component increased to some extent with respect to the predetermined voltage, and there was no great difference in the chargeability in comparison with the case of the above example.

The contact charging member 2 of FIG. 4 (B) is formed by forming a coat layer 2D having a desired resistance on the surface of a resin film 2C, and the coat layer 2D side is electrically conductive via a conductive adhesive 11. It is configured such that it is adhered to and supported by the support 9, the coat layer 2D is brought into contact with the surface of the photoreceptor 1, and a voltage is applied to the coat layer 2D from the power source 12 through the conductive support 9. In this case as well, Fourth
The same action and effect as in the case of the configuration of FIG.

At least one of the contact charging member 2 and the cleaning member 61 may be integrally formed in advance with a supporting member that shares the same. FIG. 5 (A)-
(D) has shown the various form examples.

In FIG. 5 (A), an insulating cleaning blade 61 as a cleaning member is pre-molded on the conductive support 9 so as to be integrally provided, and the conductive rubber blade 2 as a contact charging member is conductively bonded. It is firmly bonded and fixed through the agent 11.

In the same figure (B), both of the blades 61 and 2 are integrally molded and molded on the same electroconductive support 9.

In FIG. 1C, the contact charging member 2 is integrally provided on the conductive support 9 by molding, and the insulating rubber blade 61 as a cleaning member is firmly bonded and fixed via the adhesive 10. In this example, the contact charging member 2 is a conductive rubber member having a substantially circular cross section, and is gradually separated from the surface of the photoconductor on both the upstream side and the downstream side in the direction of rotation of the photoconductor of the contact portion with the photoconductor 1, which is an image carrier. An air layer portion is formed.

In the same figure (D), an insulating rubber blade 61 as a cleaning member is integrally provided on the conductive support body 9 by molding, and a conductive auxiliary support body 9A which is a separate member from the conductive support body 9 is provided. A conductive rubber blade 2 serving as a contact charging member is integrally provided by molding, and both 9 and 9A are integrated by screwing 9B after molding and dimensioning. Support 9
・ If 9A is used as a mold, it may be integrated by fusion bonding, and if it is metal, it may be integrated by bonding or tightening with screws as shown in the figure.

In either case, the reference position may be shared, and the positioning may be performed with high accuracy.

In addition, the contact charging blade 2 contacts the support 9 made of sheet metal or the like.
(Or, the sheets 2A and 2B, the sheets 2C and 2D) or / and the cleaning blade 61 is fixed by the adhesive 11 (10), the adhesive surface on the support side is as shown in FIGS. 6 (A) and (B). To Bali
Select the surface without 9c. If the blade is bonded to the surface on the side having the burr 9c as shown in FIG. 7C, the dimensional stability of the tip of the blade is deteriorated.

〔The invention's effect〕

As described above, according to the present invention, the contact charging member and the cleaning member are joined and supported by the supports having the same setting reference, so that a highly accurate contact state of the members with respect to the image carrier surface can be obtained. As a result, the cleaning effect is high, the contact charging member is not contaminated, and the charging is uniform. In addition, the space for both members is reduced, and the effect of reducing the size and weight of the device can be obtained, and the intended purpose is well achieved.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the configuration of an embodiment of the apparatus, FIG. 2 (A) is an enlarged view of the main part thereof, FIG. 2 (B) is a modification thereof, and FIG. 3 (A) to FIG. Another aspect diagram, FIG. 4 (A)
(B) is a diagram of an example in which a sheet or film form is used as the contact charging member, respectively, and FIGS. 5 (A) to 5 (D).
6A to 6C are views showing various embodiments in which at least one of the contact charging member and the cleaning member is integrally molded with the supporting member in advance, and FIGS. 6A to 6C show burrs on the supporting member. FIG. 6 is a diagram showing how to attach a contact charging member and a cleaning member in a certain case. Reference numeral 1 is a photoreceptor as an image carrier, 2 is a contact charging member, 61 is a cleaning member, and 9 is a common support member for both members 2 and 61.

Claims (8)

[Claims] 1. An image forming process means including a means for uniformly charging the surface of an image bearing member, which is rotated or rotationally moved to move its surface, is applied to form an image. An image forming apparatus of a system in which an image carrier surface is purified by a cleaning unit and repeatedly used for image formation, wherein the charging unit is a contact charging member which is brought into contact with the image carrier surface and a voltage is applied, The cleaning means is a cleaning member brought into contact with the surface of the image carrier, and the contact charging member and the cleaning member share one supporting member, are positioned and fixedly supported by the supporting member, and An image forming apparatus, wherein at least an image carrier surface contact portion of the member is made of different materials. 2. The contact charging member is applied with a voltage obtained by superimposing a DC voltage for obtaining a predetermined charging potential on a pulsating voltage having a peak-to-peak voltage that is at least twice the charging start voltage. The image forming apparatus according to item 1. 3. The image forming apparatus according to claim 1, wherein the contact charging member and the cleaning member are fixedly supported by being adhered to a supporting member which is shared with each other. 4. The image forming apparatus according to claim 1, wherein at least one of the contact charging member and the cleaning member is integrally formed with a supporting member that is shared with each other. 5. The image forming apparatus according to claim 1, wherein the support is fixedly supported by a support member that supports the image carrier. 6. The contact charging member and the cleaning member are fixedly supported on a surface of a support which is free of burrs, respectively.
The image forming apparatus according to claim 1. 7. A blade is used as at least the cleaning member of the contact charging member and the cleaning member,
The image forming apparatus according to claim 1, wherein an abutting portion of the blade with respect to the image carrier surface is an edge. 8. The method according to claim 1, wherein the support includes at least an image carrier, a contact charging member, and a cleaning device, and is provided in a process cartridge that is detachable from the main body of the image forming apparatus. Image forming device.