JPH01197766A - Image forming device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus such as a copying machine or a laser beam printer.

(Prior Art) In this type of electrophotographic image forming apparatus, the developer holding member of the image forming section is attached and detached in order to replenish developer, dispose of waste toner, or replace the photosensitive drum. It will be done. For example, FIGS. 6(a) and 6(b) show the attachment and detachment of a developer holding member in a copying machine. That is, FIG. 6(a)
1 shows a state immediately before the developing device 101 and cleaner unit 105 that constitute the image forming section are installed in the image forming section frame 109 of the main body of the apparatus, and these developing device 101 and cleaner unit 105 are attached to the upper cover as shown It is mounted in the direction of the arrow shown in the figure with 106 opened. Note that the cleaner unit 105 includes a cleaner 102 that stores waste toner.
, a photosensitive drum 103 that forms an electrostatic latent image on its surface, and a primary charger 104 that uniformly charges the surface of the photosensitive drum 103 are integrated into a unit. Further, a laser scanner 107 and a mirror 108 are housed inside the upper cover 106.

When handling a jam, as shown in FIG. 6(b), after opening the upper cover 106, the image forming unit frame 10 is opened.
9 is rotated in the direction of arrow a as shown by the solid line in the figure about axis A to open the paper conveyance path.

(Problem to be Solved by the Invention) However, when installing the developing device 101 and cleaner unit 105 shown in FIG. The opening direction of the openings formed in the photosensitive tram 103 substantially coincides with the mounting direction of the developing device 101 and the cleaner unit 105 (arrow direction in the figure), and these openings are long along the generatrix direction of the photosensitive tram 103. Therefore, there is a problem in that the toner is blown out in the direction of the arrow shown in the figure due to the shock during installation. Furthermore, when removing a jam as shown in FIG. 6(b), since the mounting direction of the first image forming section frame 109 to the main body of the apparatus and the opening direction of the opening section are approximately the same, the frame 109
When the toner is attached to the main body of the apparatus, the shock of the apparatus may cause the toner to blow out as shown by the arrow in the figure. If this type of toner blowout occurs, the inside of the device will be contaminated with toner, and in order to prevent toner blowout to a certain extent, it will be necessary to make the seal stronger, which will increase costs and prevent this toner from blowing out. There is no reliable sealing method that completely prevents blow-outs.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus that can prevent developer from blowing out when a developer holding member is attached and detached.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an image forming apparatus including developer holding means such as a developing device and a cleaner. It is characterized in that the direction of attachment and detachment from the main body is made to substantially match the opening direction of the opening formed between the developer holding means and the photoreceptor.

(Function) Since the direction in which the developer holding means is attached to and removed from the main body substantially coincides with the opening direction of the opening formed between the developer holding means and the photoreceptor, the developer is not blown out. Therefore, it is possible to obtain an image forming apparatus with less scattering.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a laser beam printer according to the present invention. In the laser beam printer, a large number of cut sheets P... are stacked on a paper feed tray 21, and each cut sheet P is The image is conveyed to the image forming section by rollers 22 and conveyance rollers 23, transferred by transfer roller 24, guided to fixing device 25, fixed by a heat roller, and then transferred to output tray 2 outside the apparatus by discharge roller 26.
7 is discharged onto the top.

By the way, the paper feed section including the paper feed tray 21, the paper feed roller 22, the transport section including the transport roller 23, the fixing section including the fixing device 25, the ejection roller 26, and the paper ejection section including the paper ejection tray 27 are located on the apparatus base. B is pivotally supported by an axis A, and these are divided at the positions indicated by the dashed lines shown in the figure, and are configured to be openable and closable.

Further, the image forming section includes a photosensitive drum KD and a cleaner section C.
A cartridge CG is constituted by integrating a 1-time charging section T and a developing section. In this embodiment, the above-mentioned negative charger T is a semiconductive elastic body of about 10 to 103 Ω·cm,
For example, DC-600 to -700V is applied to the conductive rubber roller 28.
, AC1200 to 1800VP, the photosensitive tram KD can be charged to -600 to -700V. The conductive rubber roller 28 is driven by the photosensitive drum KD and is in contact with the photosensitive drum KD under a pressure of several 100 g/cm 2 .

When image exposure is performed using the laser beam optical system, the potential of the image exposure section becomes -50 to -150V,
In the developing section, the toner is pumped up from the toner container section D1 containing toner of the same polarity as the negative charge to the vicinity of the developing sleeve 30 by the stirring means 29 and conveyed, and the toner is transferred to the rubber plate section that is in contact with the developing sleeve 30. 31, and by applying an AC bias to the developing sleeve 30 while approaching the photosensitive drum KD at a distance of 200 to 300 JL, the toner is reversely developed (jumping) onto the image exposed area of the photosensitive drum KD. developing). Then, the toner image on the photosensitive drum KD is transferred onto the cut sheet P, which is a transfer material, as described above, and the remaining toner after transfer on the photosensitive drum KD is transferred from a mylar sheet with a thickness of 50 to 1oo IL 8 degrees in the cleaner section C. The cleaner casing 33 passes through the scoop sheet 32 made of
The scraped waste toner is scraped off from the top of the photosensitive drum KD by a cleaning plate 34 fixed to the cleaning plate 34, and the scraped waste toner is collected in the waste toner container section C1. Note that the cleaned photosensitive drum KD can be used again in the next image forming process.

By the way, the cartridge CG is replaced with a new one after a certain amount of image formation, taking into account the lifespan of the photosensitive drum KD, the lifespan of the cleaning blade, the lack of toner, etc., but this replacement is performed as follows. It is done. That is, as shown in FIG. 2, the exterior cover part KX! has paper feeding, conveyance, fixing, and paper ejection sections. ! - When opened, the cartridge CG is configured to be able to be inserted and removed toward the side where part K of the exterior cover is opened, so the operator can take out the cartridge CG from the main body in a direction perpendicular to the drum generatrix direction. can. Further, a new cartridge CG is installed in the main body by operating in the opposite manner to the above-mentioned removal process, and after installation, when the outer cover part K is closed, the cartridge CG is placed in a predetermined position under pressure from the transfer roller 24. is definitely set.

Note that when part of the exterior cover K is open.

As shown in FIG. 2, the paper discharge tray 27 (see FIG. 1) has been removed and the paper feed tray 21 has been folded.

3 and 4 are diagrams showing a structure for positioning the cartridge CG on the device base B.

As shown in FIG. 3, drum bins 20 that pivotally support the photosensitive drum KD are provided on both sides of the outer frame 202 of the cartridge CG.
1. A guide portion 202a and a click spring portion 202b having spring properties are provided in a protruding manner.

On the other hand, the device base B includes a guide groove Bs in which the guide portion 202 provided on the cartridge CG side is to be fitted, a recess B2 in which the click spring portion 202b is to be engaged, and a positioning portion B3 for positioning the photosensitive drum KD. are formed on both sides. Note that the photosensitive drum KD is rotationally driven by a drive gear 35 that is pivotally supported on the side surface of the apparatus base B.

Further, contact portions 203 and 204 are formed on one side of the outer frame 202 of the cartridge CG.
．． Reference numeral 204 denotes a plate spring contact portion 101 provided on the device base B side when the cartridge CG is mounted on the device base B.
, 102.

Then, the cartridge CG is placed in the third position relative to the device base B.
When the cartridge CG is installed in the direction of the arrow in the figure, the guide part 202a provided on the cartridge CG is guided along the guide groove B1 on the cartridge base B side, and when the click spring part 202b engages with the recess B2 with a click feeling. The cartridge C
The mounting and positioning of G is completed. That is, at this time, the cartridge CG is positioned with respect to the device base B of the photosensitive drum KD by the engagement of the drum pin 201 with the positioning portion B3, and the guide groove B1 of the guide portion 202a is positioned.
The direction of rotation is fixed in a predetermined direction by fitting into the holder.

In the above, when the cartridge CG is installed on the apparatus base B as shown in FIG. 2, the photosensitive drum K in the cleaner section C and the developing section is
Since the opening direction of the opening formed between K1 and D is opposite to each other, the shock when the cartridge CG is installed causes the toner contained in the cartridge CG to move toward the direction shown by the arrow K1.
Therefore, only the toner can be effectively prevented from blowing out from the opening formed between the cleaner section C and the photosensitive tram KD in the developing section. As a result, high precision is not required for the toner seal for preventing blow-out, and an expensive sealant is not required either, thereby reducing costs and increasing the degree of freedom in design. Further, the mounting direction of the cartridge CG corresponds to the direction that induces a force to push the toner into the waste toner container section CI for storing waste toner in the cleaner section C, so that the capacity of the waste toner container section C1 is effectively utilized. Something comes up. On the other hand, in the developing section, conventionally, when the developing section was attached to the main body, toner would concentrate near the developing sleep 30, resulting in an increase in initial density during image formation, and depending on how much force was applied when attaching the developing section, toner would be concentrated near the developing sleep 30. However, in this embodiment, when the cartridge CG is installed, the toner in the developing sleeve 30 is pushed back to the developing toner container part D8, so when forming an image, By pumping up the toner near the developing sleeve 30 by the stirrer 29, a stable supply of toner is always achieved, and the image density is stabilized and density unevenness is eliminated.

Next, a modified embodiment of the present invention is shown in FIG. 5, or the image forming apparatus shown in the same figure has a pre-exposure lamp 40 installed around the photosensitive drum KD. -Next charging: S41, an image exposure/developing device 44 using a laser optical system 421, a reflecting mirror 43, a paper conveyance section 45 for paper feeding, conveyance, and fixing, and a cleaner section 46 are arranged to form a J# structure.

Incidentally, in this image forming apparatus, the developing device 44 is configured to be able to be attached to and removed from the inside and outside of the main body of the apparatus, making it easy to change colors and the like.

Therefore, the developing device 44 is installed in the direction indicated by the arrow in the figure, or
Since this direction of the device is opposite to the opening to the photosensitive drum KD, even if the mounting operation is carried out vigorously, no toner will be blown out or spilled. Further, although the cleaner section 46 is mounted in the direction of arrow M in the drawing, the mounting direction of the cleaner section 46 is also a direction in which toner does not blow out.

Incidentally, the developing device and the cleaner section may be individually attached and detached as in the above embodiments, or the cleaner section and the photosensitive drum may be integrated, and the developing device stand may be attached independently. Although the above embodiments have been explained using a laser beam printer as an example, it goes without saying that the present invention can be applied to any other image forming apparatus such as a copying machine.

(Effects of the Invention) As is clear from the above description, according to the present invention, in an image forming apparatus including a developer holding means such as a developing device and a cleaner, at least one main body of the developer holding means is Since the direction of attachment and detachment is made to substantially coincide with the opening direction of the opening formed between the developer holding means and the photoreceptor, it is possible to effectively prevent the developer from blowing out.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a laser beam printer according to the present invention, FIG. 2 is a vertical cross-sectional view showing the laser beam printer in an open state, and FIG. 3 is a partial side view showing the cartridge positioning structure of the laser beam printer. 4 is a perspective view of the same, FIG. 5 is a vertical sectional view of a laser beam printer showing a modified embodiment of the present invention, and FIGS. It is a sectional view showing a state. 30...Developing sleeve, B...device base, C...
-Cleaner section, CG...cartridge, D-...developing section, K...part of the exterior cover, KD...photosensitive drum. Patent applicant Canon Co., Ltd.

Claims (3)

[Claims] (1) In an image forming apparatus including a developer holding means such as a developing device and a cleaner, the direction of attachment and detachment of the developer holding means to at least one main body is determined between the developer holding means and the photoreceptor. An image forming apparatus characterized in that the opening direction of the opening to be formed is approximately aligned with that of the opening. (2) The image forming apparatus according to claim 1, wherein at least a developing device and a cleaner of the developer holding means and a photoreceptor are integrated as a cartridge. (3) The image forming apparatus according to claim 1 or 2, wherein the direction in which the developer holding means is attached to the main body corresponds to the direction in which the developer is pushed back into the developer holding means.