JPS61186972A - Electrostatic image forming unit and electrostatic image forming device - Google Patents

Abstract

PURPOSE:To obtain a stable copy image at all times by classifying and preparing plural kinds of electrifying devices whose electrostatic charge characteristics are different from each other, by making the mechanical constitution and shape different, and selecting and assembling the charging device in accordance with the charge characteristic of a photosensitive body to be built in. CONSTITUTION:An assembly can be executed clearly without requiring complicated electrical measurement and adjustment, when executing the assembly to a a housing 10, by meassuring and classifying in advance of an electrostatic charge characteristic of each photosensitive body 2, also bringing to unequivocal classification of an electrode positioning member for holding a fitting position of an electrification pole conforming with characteristics of the photosensitive body which has been classified separately, and designating the respective combinations. Also, in case a grid wire is used, plural kinds of wires whose pitch interval or number or wires has been changed are prepared in advance, and when an assembly is executed by combining it with an electrode having a rough pitch with respect to that which has a low photosensitive body charging characteristic, and combining it with an electrode having a fine pitch with respect to that of a high photosensitive body charging characteristic, a correct charging potential is obtained consequently, and a stable copy image is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus such as an electrophotographic copying apparatus or an information recording apparatus. More specifically, the present invention relates to an electrostatic image forming unit and an electrostatic image forming apparatus that can be combined so that when image forming parts are replaced, suitable image forming conditions are achieved according to the charging characteristics of the parts.

[Conventional technology]

Generally, in an electrophotographic copying machine, a photoreceptor consisting of a photoconductive layer and a conductive substrate is charged with positive or negative polarity, and then an electrostatic latent layer is formed by image exposure. The latent image is visualized as a toner image, and the toner image is transferred to recording paper, and the toner image is fixed on the recording paper to which the toner image has been transferred, using a heat roll fixing device, etc., to make it permanent, and a copy is obtained. The method is common. In the conventional copying apparatus lζ, the output of the discharge electrode, mainly the charging electrode, is adjusted in accordance with the charging characteristics of the photoreceptor each time the photoreceptor is assembled into a mechanical device or replaced. This is because the charging characteristics of the photoreceptors differ slightly between photoreceptors or photoreceptors with different manufacturing lofts, making it impossible to always obtain a constant copy image. Furthermore, it is made into a unit that can be attached and detached from the main body of the device,
In other words, it is conceivable to integrate the photoreceptor drum, cleaning section, and charging electrode into an integral unit, or to integrate the photoreceptor drum, developing section, cleaning section, and charging electrode into an integrated unit, which makes it easier to replace the main body of the device. A change is being considered.

In order to make the unit easily replaceable, an adjustment circuit is built into the device main body, and the output current or output voltage of the charging electrode is adjusted by adjusting the output current or output voltage of the charging electrode according to the charging characteristics of the photoreceptor. The optimum output value is set by feeding back to the circuit and manipulating a variable resistor provided in the core and changing the resistance value to change the output current or output voltage. Adjusting these conditions is complex;
This is very inconvenient when assembling or replacing, as only those with specialized knowledge can do it.

In order to solve the above problem, a charging device using a control grid electrode is used, and a constant voltage passive element (such as a varistor) is connected between the control grid electrode and the counter electrode (photoreceptor conductive substrate).
Some devices are designed to provide a stable set potential. However, for the constant voltage passive element provided in the core, a large number of elements with different characteristics corresponding to different photoreceptor characteristics must be prepared in advance and combinations must be selectively provided, making the work complicated and costly. The effects of unitization cannot be fully demonstrated.

[Problem that the invention seeks to solve]

The present invention has been made to solve the above-mentioned problems, and its purpose is to eliminate the need for complicated electrical measurements and adjustments, or elements with different characteristics during assembly or replacement. 1iiiiiiiii mechanical configuration! The object of the present invention is to provide an electrostatic image forming unit and an electrostatic image forming apparatus that automatically set the forming conditions tζ and can form stable images at all times without relying on a person with specialized knowledge. .

[Means for solving problems]

The present invention aims to achieve the above-mentioned object by preparing a plurality of types of charging devices having different charging characteristics by having different mechanical configurations and shapes. The electrostatic image forming apparatus is characterized by selecting and assembling a charging device according to the situation, and by having different mechanical configurations and shapes, multiple types of charging devices with different charging characteristics are prepared. The present invention provides an electrostatic flaw forming unit characterized in that it has a unit that selects a charging device according to the characteristics of the photoreceptor and integrates the photoreceptor and the charging device.

〔Example〕

FIG. 81 shows an embodiment to which the present invention is applied, and is a main sectional side view of an electrostatic image forming apparatus. Reference numeral 1 denotes a main body of an image forming apparatus using electrophotography, in which a photoreceptor 2 having a photoconductive layer provided on a conductive substrate is rotatably supported in the direction of the arrow by a main body drive mechanism (not shown). Around the photoreceptor drum 2, a charging electrode 3, a focusing light transmitting member (Selfoc lens array) 4, a developing device 5, a transfer electrode 6, a separating electrode 7, a cleaning device 8, and an erasing lamp 9 are arranged according to the drum rotation direction.
is installed. In the main body 1 of the image forming apparatus, a charging electrode 3, a developing device 5, a cleaning device 8, and an erasing lamp 9 are integrally assembled and supported by a housing 10 as a unit along with a photoreceptor 2.

It is. This casing 10 is guided and supported by guide rails 11 fixed to the device main body 1 side, and is configured to be detachable from the main device. In the above-mentioned forming apparatus, the surface of the photoreceptor drum 2 is uniformly charged with a predetermined polarity by the charging electrode 3, and then the document table 1, which is reciprocated at the upper part of the main body of the apparatus, is charged.
The original No. 2 is illuminated by a lamp 13, and the original image is projected onto the drum 2 via the SELFOC lens array 4 to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 5 and visualized as a toner image. - The photo plate material is fed from the transfer material feed cassette 14, and the paper feed roller 15,
The toner image is conveyed to the transfer section via the registration roller 16 in synchronization with the image area of the photosensitive drum 2, and is transferred from the transfer electrode 6Iζ. After completing the transfer, the transfer material is separated from the photoconductor drum 2 by the separation electrode 7, sent to the fixing device 18 via the conveyance guide plate 17, where it is fixed, and further transferred onto the paper ejection tray 20 via the paper ejection roller 19. The paper is ejected.

As mentioned above, since the process kit is detachable as a unit from the main unit, when the photosensitive drum 2, etc. exceeds its usable durability, only the kit is replaced, and the main unit operates as a scratch forming device again. . However, the problem with this is that even if the condition settings on the main device side are the same, different image quality may be reproduced. This is because, as mentioned above, the characteristics of the photoreceptors differ slightly depending on the photoreceptor or the manufacturing loft. In order to solve the above-mentioned problems, the present inventor has devised a method for assembling the charging electrode by changing the position and dimensions of the charging electrode without relying on adjusting the control device on the device main body side or replacing the constant voltage passive element. By changing the configuration, it was possible to form a stable copying staff at all times. FIG. 2 is an explanatory side cross-sectional view showing the mechanical configuration when the charging electrode is assembled. The structure is such that the mounting position can be changed. 21 is a conductive shield plate for the charged electrode 3;
2 is the discharge wire. Although not shown, when the charging electrode is assembled into the casing 10 in FIG. It is configured to be connected to the power supply section. Convex portions protruding outward are provided on both sides of the shield plate 21, and the convex portions are fa3
It is fitted into the d section of the electrode positioning member 24 as shown in the figure.

A charging electrode mounting member 25 having a guide groove 26 is provided on a predetermined side of the housing IO, and the width of the guide groove 26 is configured to fit the width a of the electrode positioning member 24 by 4. has been done. As shown in FIG. 3, the electrode positioning member 24 has constant widths a and d, and a plurality of types of b and 0 parts are made in stages. That is, by using the electrode positioning member 24 in which the b part is narrow and the 0 part is wide, the distance between the discharge wire 22 and the circumference of the photoreceptor 2 can be configured to be narrow when the charging electrode 3 is assembled to the housing 10. By using an electrode positioning member 24 having a wide portion b and a narrow portion 0, the distance between the discharge wire 22 and the surface of the photoreceptor 2 can be configured to be wide.

That is, when attaching the charging electrode 3 to the housing 10, an electrode positioning member is attached to the convex portion 23 of the charging electrode 3 so that the distance between the discharge wire 22 and the circumferential surface of the photoreceptor 2 is a predetermined distance that matches the characteristics of the photoreceptor. After the charging electrode 3 is inserted into the guide groove 26, the distance between the discharge wire 22 and the surface of the photoreceptor 2 is set at a position that matches the characteristics of the photoreceptor. To explain these in more detail, the charging characteristics of each photoreceptor 2 are measured and classified in advance, and charging electrodes that match the characteristics of the separately classified photoreceptors are installed for electrode positioning to maintain the position. By classifying the members into layers and specifying their respective combinations, the members can be assembled into the housing 10 in a unique manner without requiring complicated electrical measurements or adjustments. When replacing the photoreceptor, the purpose can be achieved simply by assembling it in the same manner.

FIG. 4 is a side sectional view of another embodiment of the charging electrode assembly showing the mechanical configuration. In this method, the discharge wire 22 and the conductive shield plates 21' and 21' are fixedly installed, and the position of the rear shield plate 21'' can be changed in the side view of the shield plate, and the discharge wire 22 and the variable shield plate 21'' are The idea is to change the discharge efficiency by changing the distance between the two. The assembly is the same as that of the above-mentioned embodiments in FIGS. 2 and 3 regarding the shape parts, so the explanation will be omitted. FIG. 5 shows an embodiment in which the present invention is applied to a charging system having a control grid electrode as the charging electrode 3. 27 is a conductive shield plate;
A U-shaped guide groove 27a into which four control grid electrodes 28 can be inserted is provided at the lower end of the shield plate 27. 22 is a discharge wire of a charging electrode. Although not shown, the electrode is configured to hang at a predetermined position of the housing 1o in FIG. 1, as in the case shown in the second diagram. A control grid electrode 28 for controlling corona ions is disposed in the guide groove 27a, and when the charging electrode is assembled to the housing 10 in FIG. 1 and attached to the main body of the apparatus,
The discharge wire 22 is a high voltage power supply 2 provided on the device main body side.
At 9, the control grid electrode 28 is connected to a constant voltage passive element (eg, a varistor) 30. As is well known, the control grid electrode 28 may be a mesh electrode made of stainless steel, or a plurality of metal wires (grid wire) made of gold-plated tungsten material stretched in the axial direction of the photoreceptor at equal intervals. It is configured. When mesh-like electrodes are used, several types of electrodes with different mesh roughnesses are prepared, and the combination with the photoreceptor is specified in the same manner as described above, so that assembly can be performed uniquely. This is because the amount of charge on the photoreceptor can be controlled by the roughness of the mesh. In addition, when using grid wires, prepare multiple types with different wire pitch intervals or the number of wires, and if the photoreceptor charging characteristics are low, combine them with electrodes with a coarse pitch, and For materials with high charging characteristics, by combining and assembling electrodes with fine pitches, an appropriate charging potential can be obtained and a stable copy image can be obtained. In this example, a method was exemplified in which the dimensions and position of the charging electrode were changed stepwise and divided, and the charging electrode that matched the charging characteristics of the photoconductor was selected and assembled. Of course, any possible configuration may be used.

〔Effect of the invention〕

According to the present invention, in order to change the electrode efficiency of the charging electrode in a process cartridge in which an electrode and a photoreceptor are integrally configured, the dimensions and position of the conductive shield plate are changed, or the control grid electrode is changed. Items with different mesh roughness or different pitch intervals of the core grid wires are classified in advance to suit the charging characteristics of the photoreceptor, and the layers are prepared and assembled. At the time of replacement, it is only necessary to assemble it uniquely according to the above classification, and there is no need for complicated work such as measurement or adjustment, and there is no need to arrange constant voltage passive elements that match the characteristics of the photoreceptor, so it is always stable. Since a copied image can be obtained, the present invention is very effective when assembling or replacing an electrostatic recording device or unit.

[Brief explanation of the drawing]

FIG. 1 is an embodiment to which the present invention is applied, and is a main sectional side view of an electrostatic film forming device. Figure 2 is an explanatory side sectional view showing the mechanical configuration when assembling the charging electrode, Figure 3 is a side sectional view of the positioning member for the charging electrode in Figure 2, and Figure 4 is the machine for assembling the charging electrode. FIG. 5 is a sectional side view of another embodiment showing a typical configuration, and is an embodiment of the present invention in the case of a charging system having a control grid electrode. 1... Grain forming device main body 2... Photoreceptor 3... Charging electrode 10... Housing 11... Guide rail
21... Conductive shield plate 22... Discharge wire 24... Electrode positioning member 25... Charging electrode mounting member 26... Guide groove 27...
・・Conductive shield plate 28・・Control grid electrode 29・
...High voltage power supply 30... Constant voltage passive element Applicant: Roku Konishi Photo Industry Co., Ltd. 1st Zuko 12 Fig. 2 Fig. 3 Fig. 4

Claims (2)

[Claims] (1) Multiple types of charging devices with different charging characteristics are prepared by having different mechanical configurations and shapes, and the charging device is selected and assembled according to the characteristics of the photoreceptor to be incorporated. An electrostatic image forming apparatus characterized by: (2) Prepare multiple types of charging devices with different charging characteristics by having different mechanical configurations and shapes, select the charging device according to the characteristics of the photoreceptor, and connect the photoreceptor and charging device. An electrostatic image forming unit characterized by having a unit formed integrally.