JPH0466964A - Image forming device - Google Patents

Abstract

PURPOSE:To maintain positioning precision of a required part and to form a good image by positioning a first box body provided with an image carrier and a second box body provided with an actuating means actuating on the image carrier for image formation at an integrally molded positioning part. CONSTITUTION:The positioning part 206 provided in a processing cartridge 200 of the second box body is provided with a positioning section 206a carrying out positioning of a photosensitive body and a positioning section 206b preventing inclination of the cartridge, and the integrated photosensitive drum 15 is positioned. This positioning part 206 is integrally molded with a frame body 201 of the cartridge 201, and by engaging this with a first body side positioning part, the photosensitive drum 15 of the cartridge 200 and the actuating means to the drum 15 on the first box body side are positioned. With this integrally molded structure, positioning precision can be obtained easily, and the recorded image of a good quality can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an image forming apparatus such as an electrophotographic copying apparatus and a printer for forming an image on an image bearing member such as a photoreceptor.

[Background technology]

For example, in an electrophotographic device such as a laser printer, not only the positional accuracy of the photoreceptor as an image carrier and the laser optical system that irradiates the photoreceptor with image light, but also the transportation means that conveys the transfer material to the photoreceptor. Parallelism with the photoconductor, and
The parallelism between the photoreceptor and the transfer roller that rotates in pressure contact with the photoreceptor to transfer an image onto a transfer material is also important.

This is because if this parallelism is not maintained accurately, the image will be tilted with respect to the transfer material.

In order to achieve positional accuracy between the laser optical system and the photoreceptor, it is already known that the photoreceptor support part and the support part that supports the laser scanner of the laser optical system are constructed as an integrally molded body, and this method has excellent effects. It's demonstrating itself. FIG. 4 is a schematic cross-sectional view of this laser beam printer.

Here, 1 is a process cartridge with a photoreceptor 15 inside.
, and a developing device 25, a blower 23, and a cleaning unit 9, which are working means that act on the photoreceptor for image formation. Reference numeral 6 denotes a laser optical system, which houses a rotating polygon mirror, an imaging lens, a laser light source unit, etc. inside.

A transfer roller 26 transfers the image formed on the photoreceptor onto the transfer material S, and rotates while pressing the transfer material against the photoreceptor.

A fixing unit 11 houses a fixing roller 11-1.

Reference numeral 7 designates an integrally molded body frame that supports the optical unit 6, the process cartridge I, and the photosensitive weight 5 therein, and 20 and 21 designate paper feed rollers that feed the transfer sheet S. In this laser beam printer, in order to remove jams in transfer materials such as paper and replace process cartridges, the right main body is located in the transport unit 1, compared to the left main body.
It has a structure that can be divided and opened as 00. FIG. 5 shows this in an open state.

In an apparatus having such a structure, the transfer roller 26 rotates together with the conveying unit 100 to separate and open the left main body having the photoreceptor in order to clear a jam or replace the process cartridge. This is necessary, and furthermore, it is easier to clear the jam if the paper feed roller 5 also rotates integrally with the conveyance unit.

[Problem that the invention is trying to solve]

However, as described above, if the transfer roller 26 and paper feed roller 20 are configured to be separable from the photoreceptor that forms an image, the positional accuracy of these rollers, especially the parallelism with respect to the photoreceptor 22, becomes difficult during normal image formation. It is difficult to obtain a high degree of accuracy, and printing accuracy tends to decrease.Furthermore, in order to prevent printing accuracy from decreasing, a highly rigid main body opening/closing unit and high assembly accuracy are required. This will lead to increased costs.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide an image forming apparatus that can maintain positional accuracy and form good images.

[Structure of the invention]

In order to achieve the above object, the present invention includes a first housing having an image bearing member, and a second housing having an action means for acting on the image bearing member for image formation, and the first housing and the above-mentioned In the image forming apparatus, the first housing includes a first positioning section that positions the image carrier in the first housing, and a first positioning section that positions the operating means in the first housing. However, the present invention is characterized in that it has a second positioning part that is integrally molded with the first positioning part.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

It should be noted that the same members as in FIGS. 4 and 5 are designated by the same numbers.

FIG. 1(a) and FIG. 1(b) show perspective views of a base applicable to the image forming apparatus of the present invention.

In FIG. 1(a), the base body 7, which is the first casing, is a molded product integrally formed using a mold. 6 is a laser scanner unit that generates and polarizes a laser beam.

The base body 7 further includes a first positioning portion 121 in which the process cartridge and the photosensitive drum are positioned. The process cartridge positioning section 121 includes a positioning section 121a for a photosensitive drum 121a, which is an image carrier, and a holding section 121b for holding the process cartridge in position.
has. The positioning mechanism for the photosensitive drum and process cartridge will be described in detail later.

Further, as shown in FIG. 1(b), the base 7 further includes positioning portions 131a and 131b for positioning the conveyance unit 100 that conveys the transfer material. The transport unit 100, which is the second housing, rotates around 131a as indicated by the arrow A in the figure.
When the transport unit 100 is closed, the lock lever 132 hooks onto the positioning protrusion 131b, thereby positioning and maintaining the closed state. This transport mechanism will also be explained in detail later.

This will be further explained using FIG. 1(b).

140 is a high voltage power supply that supplies high voltage to a charger, a developing device, etc.;
141 is a DC power supply that supplies DC voltage to control circuits, etc.;
Reference numeral 42 denotes a high voltage terminal for supplying high voltage to the process cartridge, and when the process cartridge is inserted, it comes into contact with the terminal 204 on the process cartridge side (FIG. 2(a)). Reference numeral 144 denotes a photosensitive drum drive gear that rotates by driving from a main motor for driving the rollers of a conveyance system (not shown) and the photosensitive drum.

Next, a positioning and supporting mechanism for the photosensitive drum and process cartridge will be explained.

FIG. 2 is a diagram showing a process cartridge that can be attached to and detached from the base, which is the first casing in FIG. 1, and FIG. 2(a) is a perspective view;
FIG. 2(b) is a partial perspective view illustrating the support of the photosensitive drum, and FIG. 2(C) is a simplified sectional view.

In addition to the photoreceptor, this process cartridge also includes a primary charger, which acts on the photoreceptor for image formation.
Although it has a developing device and a cleaning device, they are omitted in FIG. In addition, process cartridges are not limited to these.
It is sufficient to have at least one of the photoreceptor and the above-mentioned action means.

As shown in FIG. 2(a), the process cartridge 200 having the photosensitive drum 15 is covered by a frame 201, and the lower part of the frame 201 on the drum 15 side forms a paper guide part 202, and the transfer material is It guides you towards the photoreceptor.

A gear 203 is provided at the end of the photosensitive drum and engages with a drum driving gear 144 provided on the base side, and the rotation of the drum driving gear 144 causes the photosensitive drum to rotate.

204 is the aforementioned high voltage terminal.

205 is a support pin that supports the photosensitive drum 15; 206 is a positioning portion for positioning the photosensitive drum and the process cartridge with respect to the first housing; this positioning portion 206 is inserted and fixed into the positioning portion 121 on the first housing side. By this, positioning with respect to the main body is performed.

Positioning section 20 provided in this process cartridge
6 is a positioning portion 20 for positioning the photoreceptor;
6a, a positioning portion 206b for preventing tilting of the process cartridge, and a click portion 206c.

206a has an arcuate shape concentric with the photoreceptor, and is positioned by engaging with the first housing side positioning portion 121a.

The click portion 206c elastically engages with the main body side holding portion 121b, thereby preventing the process cartridge from moving under a light load.

This click portion can prevent image deterioration due to misalignment of the cartridge when slight vibrations are applied to the device. Naturally, the elastic holding force due to the click part is
When the operator attaches and detaches the process cartridge, the force is barely enough to cause an obstacle.

This positioning portion 206 is connected to the frame 2 of the process cartridge.
It is integrally molded with 01. However, the click part 206
c is configured to provide a slight gap of approximately 1 inch between the frame and the frame in order to add elasticity.

A mechanism for supporting the photosensitive drum will be explained with reference to FIG. 2(b).

A positioning hole 15a is provided at the center of the side wall of the photosensitive drum 15. The positioning projection 205a of the support pin is inserted into this positioning hole, thereby determining the rotational center position of the photosensitive drum.

The support pin 205 is fixed to the frame 201 of the process cartridge with a screw 207. The arc diameter of the support pin 205 is
The inner diameter of the arc of the positioning portion 206a of the photosensitive drum is equal to or slightly larger than the inner diameter of the arc, and the positioning accuracy is improved by preventing backlash.

FIG. 2(c) shows a cross section of this support mechanism.

In the figure, the support pin 205 on the left side has an electrode 205b, and the photosensitive drum is grounded by this electrode 205b.

Next, the transport unit, which is the second housing, will be explained with reference to FIG. 1(b).

This conveyance unit 100 is equipped with a transfer roller 26 which is an action means for performing a transfer action on the photosensitive drum, and when the conveyance unit 100 is in a closed state, this transfer roller is provided on the front surface of the base portion 7 and the transfer roller is It is engaged with a bearing portion 145 that positions the base, and is held in a position with sufficient accuracy with respect to the photoreceptor 15. As a result, the transfer is performed correctly, the transfer material is not skewed during transfer, and high-quality printing can be obtained.

Further, the paper feed roller 20.2I that supplies the transfer material to the transfer roller 26 is also engaged with the positioning portion 147 of the base 7, and since it is positioned in the first housing, the parallelism between the photoreceptor I5 and the transfer roller 20.2I is It has sufficient positional accuracy with respect to the roller 26.

When the transfer material jams at the paper feed position where the paper feed rollers contact each other and at the transfer position where the photoreceptor and transfer roller contact, the transfer material is jammed in the transport unit 1, which is the second housing, as shown in FIG. 1(b).
Jam handling is possible by dividing and opening 00 to the base, which is the first casing.

Next, the recording process will be explained using FIG. 4.

A laser beam emitted from a semiconductor laser and modulated according to recording information scans over a photoreceptor 15 that is uniformly charged by a primary charger such as a charging roller 23, for example.

The electrostatic latent image formed on the surface of the photoreceptor by this laser exposure is visualized by the developing device 25. This developed image is transferred onto a transfer material such as a sheet conveyed by a conveying means, with a transfer roller to which a voltage is applied coming into contact with the back side of the transfer material. This transfer roller may be provided so as to be in contact with the photoreceptor when there is no transfer material between it and the photoreceptor, or may be provided so as to have a gap between it and the photoreceptor that is smaller than the thickness of the transfer material. It's okay.

The transfer material to which the developed image has been transferred is fixed by the fixing means 11 and then discharged outside the machine.

Although the present invention has been described above based on examples, the present invention is not limited to these examples and can be modified in any way within the technical concept.

For example, a hologram, a carbano mirror, or the like may be used as the deflecting means, and a He-Ne laser or the like may be used as the light beam generation source.

Further, in the above embodiment, a transfer roller was provided as a means for acting on the image carrier on the side of the second housing that is separated from the first housing.
However, the present invention is not limited to this, and it is also possible to provide a primary charger and a developing device, which are acting means, on the second housing side, for example.

Other embodiments of the present invention may include the following. As shown in FIG. 3, a paper feed roller 20 is assembled to the transport unit 100 and is rotatable together with the transport unit. Therefore, in the case of jam clearance, it is easy to dispose of paper jammed in the paper feed section. In this case, when the transport unit 100 is closed, the paper feed roller 20
A bearing portion 146 which is a positioning portion provided on the base 7
The photoreceptor 15 and the transfer roller 26 are engaged with each other with sufficient positional accuracy.

〔Effect of the invention〕

As explained above, according to the present invention, high precision is not required for assembly, and positional precision can be easily achieved by integral molding, so high quality recorded images can be obtained.

[Brief explanation of drawings]

FIG. 1(a) is a perspective view showing a base applicable to the embodiment of the present invention, and FIG. 1(b) is a perspective view showing a state in which a transport unit is attached to the base of FIG. 1(a). , FIG. 2(a) is a perspective view showing the process cartridge, FIG. 2(b) is a partial perspective view showing support for the photosensitive drum of the process cartridge, FIG. 2(C) is a simplified sectional view of the process cartridge, 3 is a perspective view showing another embodiment of the present invention, FIG. 4 is a sectional view showing the prior art, and FIG. 5 is a sectional view when the conveyance unit of the apparatus shown in FIG. 4 is opened. In the figure, 15... Photosensitive drum 100... Transport unit 6... Scanner unit 200... Process cartridge

Claims (1)

[Scope of Claims] (1) A first housing having an image bearing member, and a second housing having an action means that acts on the image bearing member for image formation,
In the image forming apparatus in which the first housing and the second housing are separably provided, the first housing includes a first positioning portion for positioning the image carrier in the first housing, and a first positioning portion for positioning the image carrier in the first housing, and a first housing for positioning the image carrier in the first housing. An image forming apparatus comprising: a second positioning section positioned in the first housing and integrally molded with the first positioning section. (2) The image forming apparatus according to claim 1, wherein the action means is a transfer means that comes into contact with the back side of the transfer material in order to transfer the image on the image carrier onto the transfer material. (3) The image forming apparatus according to claim 1 or 2, wherein the transfer means is a rotating body. (4) The device has a conveying means for conveying the transfer material, and the first housing is integrally molded with the first and second positioning parts to position the conveying means in the first housing. The image forming apparatus according to claim 2 or 3, further comprising a third positioning section having a second position. (5) The image forming apparatus according to claim (4), wherein the second housing includes the conveying means. (6) The first casing has a process cartridge that is removably attached to the first casing, and the process cartridge includes the image carrier and at least one component that acts on the image carrier for image formation. 6. The image forming apparatus according to claim 1, further comprising an operating means.