JPH01321445A - Image forming device - Google Patents

Abstract

PURPOSE:To make a photosensitive body directly removable by automatically retreating and separating a toner density detecting member and/or a separating claw member of a transfer paper, provided on the periphery surface of the photosensitive body responding to the loading position of the photosensitive body unit. CONSTITUTION:When the photosensitive body unit A is removed from the device main body and, for example, loaded on a flat surface of a table T, with its posture tipped by 90 degrees, a working part 19D of a cover member 19 is pressured by the action of a torsion spring 21 with the photosensitive unit A's own weight. As a result, the cover member 19 rotates with the supporting axis as a fulcrum, a photoelectric type sensor 16, the separating claw 17, and a toner receiving plate 18 are moved and retreated from the periphery surface of the photosensitive body (drum) 11 simultaneously, and further retained in a specified clearance. Thus exchanging can be freely carried out without going through the tedious procedures of mounting and dismounting the members placed close to the periphery surface of the photosensitive body drum 11 or damaging the photosensitive drum 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that forms an image using toner, and particularly relates to a detection member and/or a detection member that detects toner density on an image formed on a photoreceptor. Or it relates to the attachment structure of the separation claw member of the transfer paper.

[Background of the invention]

In recent years, in image forming apparatuses such as electronic photocopiers for office use, it is necessary to check the exact positional relationship of each image forming means such as the photoreceptor (drum or belt), charger, developing device, transfer device, and cleaning device. In order to facilitate handling during maintenance and management, a method is adopted in which the unit is assembled into a common support frame and then attached to the main body of the apparatus.

This kind of unitization of the image forming section was developed, for example, by the
As shown in Publication No. 3-10424, in the normal case, due to its lifespan and frequency of maintenance, the developing device is made into a unit separately from other means, and the developing device is separated from the photoreceptor (drum) and charger described above. , a transfer device, a cleaning device, and other units are attached to and removed from the main body of the device separately. However, the invention disclosed in Japanese Patent Publication No. 63-10425 was not capable of detecting toner concentration.

[Problem that the invention seeks to solve]

However, even if it is unitized as mentioned above, if we look at the photoconductor unit that incorporates the photoconductor (drum), cleaning device, etc., in addition to the above-mentioned image format means, toner is stored in an area exceeding half the circumference of the photoconductor (drum). Because the density detection member, transfer paper separation claw, etc. are provided, it is not possible to replace the photoreceptor (drum) alone even if the photoreceptor unit is removed, so it is necessary to remove each of the above-mentioned members in advance. After replacing the photoreceptor (drum), these members must be reattached.

In this case, of course, one has to handle the detection member and the cover that covers the separation claw, as well as the plate that receives the toner leaking from the cleaning device, so the toner often stains the hands and workbench, and the work is not easy at all.

The present invention solves this problem and improves it. As a result, when the photoreceptor unit is taken out and placed on a workbench, etc., each of the above-mentioned members including the toner concentration detection member is automatically moved from the circumference of the photoreceptor. The object of the present invention is to provide an image forming apparatus in which a photoreceptor (drum) can be directly removed by separating the photoreceptor (drum) from the image forming apparatus.

[Means for Solving the Problems] The above object is such that the photoconductor unit, which is provided with a photoconductor, an electrostatic latent image forming means around the photoconductor, and a cleaning means, is configured to be independently attached to and detached from the main body of the apparatus. In the image forming apparatus, a toner concentration detection member and/or a transfer paper separation claw member provided facing the circumferential surface of the photoreceptor are automatically moved to the photoreceptor according to the orientation of the photoreceptor unit when it is placed. This is achieved by an image forming apparatus characterized in that it is configured to be retracted and separated from the circumferential surface of the body.

〔Example〕

An embodiment of the present invention is shown in FIGS. 1 to 4.

FIG. 4 shows the general structure of the image forming apparatus of this embodiment. Among the main process equipment for image formation, the photoreceptor (drum or belt) and the electrostatic latent image forming means surrounding it are charged. Pre-exposure, charging, and erasing devices and a cleaning device serving as cleaning means are housed in the photoreceptor unit A, and the developing device is housed in the developing unit B, which is then attached to the main body of the apparatus.

The photoreceptor unit A is guided by a pair of left and right guide rails from the front of the apparatus, inserted into the main body of the apparatus, and positioned by engagement of guide bins.

On the other hand, the developing unit (B) is placed on a developing garage located outside the main body of the apparatus, and is pressed against the photoreceptor of the photoreceptor unit A by the urging of a pressing member.

When the photoreceptor unit (A) and the developing unit (B) are installed in the apparatus main body, the above-mentioned process equipment accommodated and supported therein is connected to the power supply or drive device of the apparatus main body, and connected to other related process equipment. The image forming function is demonstrated in conjunction with the image forming function.

That is, when copying is started, the photoconductor unit A
When the photoreceptor drum begins to rotate and a negative potential is applied to its circumferential surface due to the discharge of the charger, the exposure mounting l
An electrostatic latent image of the image is formed by projecting an image on the original document by scanning.

Next, in the developing unit I-B, the developing device operates to convert the electrostatic latent image on the photoreceptor drum surface into a toner image, which is then fed to the transfer device 4 located in the main body of the apparatus below the photoreceptor unit A. Device 3 consisting of paper cassette 2
The image is transferred onto transfer paper that is fed through the process.

The transfer paper on which the toner image has been transferred is separated from the circumferential surface of the photoreceptor drum in the separator 5 and sent to the fixing device 7 via the conveyance device 6, where the image is fixed, and then transferred to the paper output tray outside the main body of the apparatus by the paper discharge roller 8. It is discharged at 9.

On the other hand, the peripheral surface of the photoreceptor drum from which the transfer paper has been separated is cleaned by removing residual toner in a cleaning device housed in the photoreceptor unit A, and is further erased from residual potential by a pre-charging exposure device, and then enters the next image forming process. .

FIG. 1 shows the layout of each process equipment in the photoreceptor unit A.

11 is a photoreceptor drum that rotates in the direction of the arrow; 12 is a pre-charging exposure device that removes residual charges on the photoreceptor (drum) 11; 13 is a charger; and 14 is used to erase charges outside the image-corresponding area. An erasing device 15 is a cleaning device, which includes a toner guide roller 15 that rotates as a result of being in pressure contact with a cleaning blade 15A that is in pressure contact with the photoreceptor drum 11.
It has a built-in B.

Reference numeral 16 denotes a photoelectric sensor which is a detection member that detects the toner density of the standard plate image formed on the photoreceptor drum 11 based on the reflection density on the photoreceptor, and detects information obtained by the photoreceptor 16. Accordingly, the developing unit l-B
The amount of toner supplied is controlled.

Reference numeral 17 denotes a separating member, that is, a separating claw, which mechanically peels off the transfer paper that could not be separated from the circumferential surface of the photoreceptor (drum) 11 even by the separator 5. It is biased counterclockwise as a fulcrum, and its right end tip is brought into light contact with the circumferential surface of the photoreceptor (drum) 11.

Reference numeral 18 is a thin elastic plate made of mylar, PET, etc. provided to prevent toner leaking from the pressure contact portion of the toner guide roller 15B of the cleaning device 15 and the photoreceptor (drum) 11 from falling into the transfer paper conveying portion. The toner tray is a plate.

Reference numeral 19 denotes a cover member that mounts and supports the photoelectric sensor 16, the separation claw 17, and the toner receiver plate 18, and also serves as a conveyance guide on the upper part of the conveyance device 6, and is installed on the photoreceptor unit A. The cleaning device 1 is biased counterclockwise by the action of the torsion spring 21 using the support shaft 20 as a fulcrum.
It is stopped by contacting the stopper 15G at the bottom of No.5.

In this state, that is, in the attitude shown in FIG. 1, the photoelectric sensor 16, the separating claw 17, and the toner receiver plate 18 are all disposed at positions suitable for their respective functions and purposes, and the state is as follows. It is maintained by the biasing force of the spring 21.

FIG. 3 shows the structure of the cover member 19 and the cover member 1.
9 shows the structure of mounting and supporting each of the above-mentioned members.

The cover member 19 is a highly rigid sheet metal member bent into a step-like shape, and consists of three surfaces: a vertical surface 19A, a bottom surface 19B connected to the vertical surface 19B, and a top surface 19c. At a position corresponding to the center, the photoelectric sensor 16 is attached together with a substrate 16A to directly face the circumferential surface of the photosensitive drum 11 via a support base 16B.

A pair of separation claws 17 are further rotatably attached to the left and right vertical surfaces 19A sandwiching the photoelectric sensor 16 via support frames 17A, and as described above, the right end portion is moved by the biasing force due to the balance of its own weight. Photoreceptor (drum) 1
It is installed so that it can come into contact with 1.

Further, the toner receiver plate 18 is bonded to the lower surface of the bottom surface 19B, and has a notch portion overlapped with the separating claw 17. The toner receiver plate 18 has its leading end positioned as close as possible to the photoreceptor (drum) 11.

On the other hand, the upper surface 19C has a pair of arm-shaped actuating parts 19D and a pair of bent parts 19E each having a shaft insertion hole at both ends thereof, and the bent parts 19E are inserted into the above-mentioned support shaft 20. By doing so, the cover member 19 is pivotally attached to and held by the photoreceptor unit A.

A torsion spring 21 is fitted onto the inside of the bent portion 19H of the support shaft 20, and when attaching and holding the photoreceptor unit A, one end of the torsion spring 21 is inserted in the direction indicated by the broken line. The torsion spring 21 is biased and assembled to the outer wall of the cleaning device 15 at the position shown by the dashed line, that is, in a state where the torsion spring 21 is fully charged.

Note that in this assembled state, the actuating portion 19D is placed in a state in which it slightly protrudes from the outline of the photoreceptor unit A.

Therefore, when the photoreceptor unit A is taken out from the main body of the apparatus and placed on a flat table surface T with its posture tilted 90 degrees as shown in FIG. Torsion spring 2 due to the weight of Units l-A
It is pressed against the action of 1.

As a result, the cover member 19 rotates clockwise about the support shaft 20, and the photoelectric sensor 16 and separation claw 1
7. The toner receiver can simultaneously move and retract the plate 18 from the circumferential surface of the photoreceptor (drum) 11 and hold it at a predetermined spaced position.

Note that the actuating portion 19D can also be pressed when the photoconductor unit A is attached to the main body of the apparatus, so that in the unlikely event that the transfer paper is not peeled off by the separation claw 17, a jam condition may occur. It can also be used to remove the transferred paper.

〔Effect of the invention〕

According to the present invention, the photoconductor drum is not damaged without the need for the troublesome work of removing and attaching components located very close to the circumferential surface of the photoconductor drum, such as the toner concentration detection member and separation claw. can be exchanged freely,
Due to the simplification of the work, an image forming apparatus that can be constantly maintained and provides excellent image quality has been provided.

[Brief explanation of the drawing]

1 and 2 are cross-sectional configuration diagrams of a photoreceptor unit of an image forming apparatus of the present invention, FIG. 3 is a perspective view of the main parts thereof, and FIG. 4 is a schematic configuration diagram of the apparatus. A...Photoconductor unit B...Developing unit 11...Photoconductor (drum) 15...Cleaning device 16...Photoelectric sensor I7...Separation member (separation claw) 18...Toner The receiver is a plate 19...Cover member 19D...Operating part 19E...Bending part 20...Support shaft 21...Torsion spring

Claims (1)

[Claims] In an image forming apparatus in which a photoreceptor unit including a photoreceptor, an electrostatic latent image forming means around the photoreceptor, and a cleaning means is arranged so that the photoreceptor unit can be attached to and removed from the apparatus body independently, The toner concentration detection member and/or the transfer paper separating claw member provided in the photoreceptor unit are configured to be automatically retracted or separated from the circumferential surface of the photoreceptor unit depending on the orientation of the photoreceptor unit when it is placed. An image forming apparatus characterized by: