JPH05232751A - Image forming unit with protection sheet - Google Patents

Abstract

PURPOSE:To protect both a photo-sensitive substance and a sheet transport path by providing a protection sheet removably, which encloses a belt-form photo-sensitive substance, and enwrapping an image forming unit with this protection sheet while it also encloses the transport path. CONSTITUTION:A belt-form photo-sensitive substance 2 is arranged in a casing 1 of an image forming unit and given a tension by a drive roller 3 borne by the casing 1, a follower roller 4, and tension roller 5 with the aid of a tension spring 6. Each sheet of paper fed from a sheet feeder cassette is transported to upstream of the sensitive substance 2 while gliding on a sheet transport path 8 with the timing generated by a register roller couple 7. The sheet transporting route is of such configuration that the image forming unit is enwrapped with a protection sheet 10 while it encloses the sheet transport path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming unit loaded in an image forming apparatus such as a copying machine, a facsimile machine, a laser printer, etc. Without exposing the surface to outside light
The present invention also relates to an image forming unit having a protective sheet for enabling the replacement of the photosensitive surface without touching it with an operator's hand or the like.

[0002]

2. Description of the Related Art For example, in an electrostatic copying apparatus, a belt-shaped photosensitive member or a drum-shaped photosensitive member which is stretched by a driving roller, a driven roller and a tension roller is disposed in the center of the inside of the copying machine main body. Various devices such as a charging device, an optical lens system, a developing device, a transfer device, a peeling device, and a cleaning device are provided around the surface of the photoconductor to configure a copying process. There is.

A paper conveying path is formed above the copying process section, and a conveying roller is arranged, and the paper in the paper feeding cassette is fed to the copying process section by the rotation of the paper feeding roller. To be done.

With the above construction, at the time of copying operation, the original placed on the original table formed on the upper surface of the main body of the copying machine is scanned by the optical system light source in synchronization with the rotation of the photosensitive belt. The photoreceptor belt is uniformly charged with an electric charge of a single polarity by the charger, and the surface thereof is exposed with the reflected light from the document due to the optical system light source. By this exposure, an electrostatic latent image is formed on the surface of the photoreceptor belt, and the developer charged with an electric charge of the opposite polarity is supplied from the developing device and visualized. In synchronization with the rotation of the photoconductor belt, the paper is fed from the paper feed cassette by the paper feed / transport rollers, and the developer adsorbed on the surface of the photoconductor belt is transferred by the transfer charger. After that, the paper is heated and pressed by the fixing roller, the developer is fixed, and the paper is discharged to the outside by the paper discharge roller.

In such a copying machine, if it is used for a long period of time, the photosensitivity of the photoconductor deteriorates due to the life of the photoconductor, so that it is necessary to periodically replace the photoconductor with a new photoconductor.

Therefore, conventionally, the door of the copying machine is opened, the inside of the copying machine main body is opened, the deteriorated old photoconductor is removed, and then it is taken out from the packaging box and the light-shielding protective sheet is peeled off to expose the photoconductive surface. Or attach a new photoconductor,
Alternatively, the photoconductor is replaced by first mounting a new photoconductor with the protective sheet still attached and then peeling off the protective sheet.

However, in the case of such a conventional method, since the inside of the copying machine main body is opened at the time of replacement, the photosensitive surface of the replaced new photosensitive member may be exposed to outside light such as room light or direct sunlight, or the exposure thereof. There is a drawback that fingerprints are apt to be attached to the surface by the hand of an exchange operator, and there are various problems described below.

That is, the surface of the photosensitive member is generally formed by forming an organic photosensitive layer on a conductor. However, this organic photosensitive layer is apt to cause photo-fatigue when exposed to room light or sunlight. This is a serious problem in practical use because it has a harmful effect such as impairing the charging property and causing a change in sensitivity, and it takes a long time to recover from the above-mentioned light fatigue. In addition, when performing the performance check immediately after the replacement of the photoconductor, there is a problem that the true performance cannot be obtained due to light fatigue.

Further, if a fingerprint is attached to the photosensitive surface, there is a problem that the quality of the photosensitive surface is liable to be altered or a fingerprint appears on the copy, which adversely affects the image quality of the copy. Further, the mechanical strength of the photosensitive layer is extremely small, and therefore the surface thereof is easily scratched, and when scratched, it appears in the image.

Therefore, the replacement of the photoconductor is usually carried out by an expert who is familiar with the work so as not to bring the photoconductor surface into contact with the above-mentioned various devices. It was impossible to prevent.

[0011]

Therefore, as means for solving such inconveniences and preventing optical damage and mechanical damage, for example, JP-A-61-3185 and JP-A-61-223772 are known. Publication, JP-A-63-19664
JP-A No. 63-19665, JP-A No. 2-2
In Japanese Patent No. 48979, Japanese Utility Model Laid-Open No. 62-12170, and Japanese Utility Model Laid-Open No. 63-74641, a method is known in which a protective sheet is wound around the surface of a photoconductor when the photoconductor is replaced.

However, in these, the protective sheet is wound so as to cover the photoconductor itself, and no consideration is given to the paper transport path and the like.

However, in order to control the behavior of the paper,
It is also important to secure the size of the paper transport path having a narrow dimensional tolerance and to maintain the smoothness of the transport path. Further, if the roller surface of the registration roller that measures the timing when the paper enters the photoconductor is scratched, there is a risk of a resist jam, and the surface must also be protected.

Therefore, it is an object of the present invention to provide a protective sheet which plays a role of protecting the photosensitive member and a sheet conveying path.

[0015]

The present invention solves this problem by
In an image forming unit having a belt-shaped photosensitive member covered with a removable protective sheet and a casing accommodating the belt-shaped photosensitive member and having a paper conveying path, the protective sheet also covers the paper conveying path and is wound around the image forming unit. It is solved by being done.

It is preferable that the protective sheet is hung on the hook portion of the image forming unit.

It is more preferable if the cuts in the hooked portions of the protective sheet are consistently cut like slits from the end of the hole to be inserted in the hooked portion of the image forming unit to the end of the protective sheet itself. Is.

Conveniently, the protective sheet is wound around the image forming unit so as to cover the lower roller of the pair of registration rollers.

The protective sheet is preferably wound around the image forming unit so that it can be pulled out to the operator side after the image forming unit is loaded in the image forming apparatus main body.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments based on the drawings.

FIG. 1 is a schematic sectional view of the construction of an image forming unit using a belt-shaped photoreceptor.

A belt-shaped photoreceptor 2 is arranged in a casing 1 of the image forming unit. The photoconductor 2 includes a driving roller 3 and a driven roller 4 supported by the casing 1.
It is stretched by the tension roller 5. The tension roller 5 applies tension to the photoconductor 2 by the action of the tension spring 6. The sheet fed from the sheet feeding cassette (not shown) is conveyed to the upper side of the belt-shaped photoconductor 2 while sliding on the sheet conveying path 8 at a timing by the registration roller pair 7. The paper transport path is indicated by reference numeral 9.

FIG. 2 is a schematic sectional view showing a state in which the protective sheet 10 according to the present invention is wound around the image forming unit so as to cover the paper conveying path, and FIG. 3 is a perspective view thereof. This protective sheet 10 should be made of a material that has a light-shielding property and does not cause cracks or the like on the surface of the belt-shaped photosensitive member. Since the protective sheet is wound as shown in the figure, the exposed portion of the belt-shaped photoconductor 2 between the drive roller 3 and the driven roller 4 is protected from light and human hands (fingerprints). In addition, during transportation and storage,
If a mechanism for releasing the pressure of the tension spring 6 is used, the release of the pressure causes the belt 2 to slacken, and if no care is taken, the belt-shaped photosensitive member 2 portion between the drive roller 3 and the tension roller 5 is removed. And casing 1,
There is a possibility that the casing portion 11 of the transfer charger may approach or contact with the casing portion 11. However,
In the present invention, since the protective sheet 10 extends to the portion, the belt-shaped photoreceptor 2 and the casing 1,
It is prevented that the surface of the photoconductor is damaged due to contact with the casing 11.

Since the protective sheet 10 also covers the paper transport path 8 and the rollers below the registration rollers 7,
It is prevented that the paper transport path 8 and the lower roller are damaged.

FIG. 4 is an enlarged perspective view showing a state in which the protective sheet 10 is hooked on the hooking portion 12 (lower left portion in FIG. 2) of the image forming unit. FIG. 5 shows a detailed plan view of the hooked portion of the protective sheet 10. The cut is made in the sheet without leaving a sheet member in the middle from the end of the hole 13 to be inserted in the hooking portion 12 of the image forming unit to the end of the protective sheet itself, that is, without forming a perforation. It is cut.

FIG. 6 shows a state in which the image forming unit is loaded in the main body 14 of the image forming apparatus while the protective sheet 10 is still wound. In this case, the protective sheet 10 is wound so as to be pulled out to the operator side, that is, the front side as seen in the drawing.

[0027]

In the image forming unit according to the first aspect of the present invention, since the protective sheet is wrapped around the image forming unit so as to cover the paper conveying path as well, the protective sheet for the photoreceptor also serves to protect the paper conveying path. The added value of the protective sheet will be increased.

In the image forming unit of claim 2,
Since the protective sheet is hung on the hooked portion of the image forming unit, when the protective sheet is fixed to the image forming unit as seen in a part of the conventionally known protective sheet, in addition to the effect of claim 1. Therefore, it is not necessary to use tape or glue, and therefore, the work of cutting, pasting or gluing the tape is eliminated, and it is not necessary to increase the number of parts, resulting in a total cost reduction.

In the image forming unit of claim 3,
3. The cut of the hooked portion of the protective sheet is consistently cut like a slit from the end of the hole to be inserted in the hooked portion of the image forming unit to the end of the protective sheet itself. In addition to the effect of (3), the peeling force (pulling force) of the protective sheet is reduced compared to, for example, a perforated shape, and the operation of the operator is significantly facilitated. Further, since it has a slit shape, the protective sheet used once can be reused.

In the image forming unit of claim 4,
The protective sheet is wound around the image forming unit so as to cover the lower roller of the pair of registration rollers as well.
In addition to the above effect, it is possible to prevent the occurrence of resist jam and skew due to scratches on the resist roller.

In the image forming unit of claim 5,
Since the protective sheet is wound around the image forming unit so that it can be pulled out to the operator side after the image forming unit is loaded into the main body of the image forming apparatus, the operator takes special care in addition to the effect of claim 1. It is possible to remove the protective sheet without any need.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a configuration of an image forming unit using a belt-shaped photoreceptor.

FIG. 2 is a schematic cross-sectional view showing a state in which the protective sheet according to the present invention is wound around the image forming unit so as to cover the paper conveyance path as well.

3 is a perspective view corresponding to the state of FIG. 2, FIG. 3 (a) shows a state after the protective sheet is attached to the image forming unit, and FIG. 3 (b) shows a state after the protective sheet is removed from the casing. It shows the state of.

FIG. 4 is an enlarged perspective view of a state in which the protective sheet is hooked on the hooking portion of the image forming unit.

FIG. 5 is a detailed plan view of the hooked portion of the protective sheet in FIG.

FIG. 6 is a diagram showing a state in which the image forming unit is loaded in the main body of the image forming apparatus while the protective sheet is still wound.

[Explanation of symbols]

 1 Casing 2 Belt-shaped Photoreceptor 3 Drive Roller 5 Tension Roller 7 Registration Roller Pair 8 Paper Conveying Path 10 Protective Sheet 12 Hooking Part

Claims (5)

[Claims] 1. An image forming unit comprising: a belt-shaped photosensitive member, which is to be loaded inside an image forming apparatus main body, is covered with a detachable protective sheet; and a casing which houses the belt-shaped photosensitive member and is provided with a paper transport path. The image forming unit, wherein the protective sheet is wrapped around the image forming unit so as to cover the paper conveying path as well. 2. The protective sheet is hung on a hook portion of the image forming unit.
The image forming unit according to item. 3. The cut of the hooked portion of the protective sheet is consistently cut like a slit from the end of the hole to be inserted in the hooked portion of the image forming unit to the end of the protective sheet itself. The image forming unit according to claim 2, wherein: 4. The image forming unit according to claim 1, wherein the protective sheet is wound around the image forming unit so as to cover the lower roller of the registration roller pair. 5. The protective sheet is wound around the image forming unit so that it can be pulled out to the operator side after the image forming unit is loaded in the image forming apparatus main body. The image forming unit described in.