JPS6318367A - Image forming device - Google Patents

Abstract

PURPOSE:To easily maintain the accuracy of relative positions of a photosensitive drum and an exposing means by maintaining the distance between the exposure means and the photosensitive drum by a guide roller arranged in parallel to the drum shaft. CONSTITUTION:An LED head 2 as an exposing means is guided by a guide shaft 6 whose axis is directed to the center of the drum and energized by a spring 7 toward the photosensitive drum 1 to bring simultaneously the guide roller 5 which is arranged in parallel to the axis of the photosensitive drum 1 and coupled with the LED head 2 into contact with the surface of the photosensitive drum 1. While the guide roller 5 and photosensitive drum 1 are in contact with each other, the photosensitive drum 1 is moved under the guidance of a guide groove 21a at right angles to its axis to absorb force applied at the time of the butting between the drum 1 and roller 5 through the rotation of the roller 5, thereby preventing the surface of the drum 1 from damaging. Further, a process cartridge 12 which supports the drum 1 is extracted at right angles to the axis of the drum 1 in a device-opened state. Consequently, the relative position accuracy between the exposure means and drum surface can be maintained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image forming apparatus using electrophotography.

[Conventional technology]

Conventionally, as a type of device for attaching and detaching a process cartridge to an image forming apparatus main body, an image carrier, a developing device, and a cleaner are integrally supported in the process cartridge, as shown in Japanese Patent Publication No. 58-54392, and the axis of the image carrier is There are some that can be attached and detached in the axial direction of the process cartridge, and as in JP-A-58-139162 and 60-14249, when the image carrier is stored in the axial direction, a part of the process cartridge is connected to the exposure means or the main body of the apparatus. There is a structure in which a mating portion is provided to maintain a relative distance between the process cartridge and the exposure means.

[Problem that the invention seeks to solve]

In this type of image forming apparatus, the transfer paper is generally fed in synchronization with the rotation of the photoreceptor drum, which is the image carrier, so that there is no relative movement with the drum surface. is perpendicular to

For this reason, paper feed rollers, etc. are arranged parallel to the axis of the photoreceptor drum, and when releasing the pressure on the rollers inside the main body in order to remove paper that has become jammed while running inside the main body, this parallelism must be maintained. To maintain accuracy, it is desirable to move the rollers while they are moving.

In addition, in inexpensive devices, it is more efficient to perform this paper removal process in one place rather than in multiple parts, so the device is divided into two parts with an axis parallel to the axis of the photoreceptor drum as the pivot It often opens like a shell.

However, in the conventional image forming apparatus described above, since the photoreceptor drum is attached and detached in the axial direction, the attachment/detachment hole is opened in the axial direction, and along with the bivalve-shaped opening of the device, the inner opening of the case is opened. area becomes larger and the rigidity of the device decreases. In addition, since the paper feeding direction and the direction of attaching/detaching the photoconductor drum are perpendicular to each other, additional space is required around the am part of the device for accessing the paper and space for attaching/detaching the photoconductor drum. Efficiency decreases.

In addition, the relative positional accuracy between the exposure means and the drum surface due to the above-mentioned engagement is the drum surface accuracy with respect to the drum shaft, the mounting accuracy of the drum shaft, the positional accuracy between the shaft attachment part and the engaging part, and the positional accuracy between the engaging part and the exposing means. It is the accumulation of various precisions such as the positional precision of
If you don't manage the accuracy of all parts, you won't be able to maintain the overall accuracy.

An exposure means that does not have enough margin for the image formation position by the exposure means has the disadvantage that the image is likely to be blurred.

An object of the present invention is to provide an image forming apparatus that solves the above problems.

[Means for solving problems]

The present invention provides an image forming apparatus that includes a process cartridge that incorporates an image carrier and an image forming process device disposed close to the image carrier, and is removably attached to an apparatus main body. an exposure means that is set in a direction perpendicular to the axis of the image carrier near the process where the process cartridge is finally connected to the apparatus main body, and forms an electrostatic latent image on the image carrier; means for movably guiding the means in the direction of the image carrier, means for biasing the exposure means in the direction of the image carrier, and a means coupled to the exposure means and parallel to the axis of the image carrier. placed on the axis.

The image forming apparatus includes at least one guide roller disposed at a position where the biasing means contacts the image carrier when the process cartridge is installed in the apparatus main body.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1) As shown in FIGS. 1 and 3, an image forming apparatus according to the present invention has an apparatus main body divided into two parts, an upper frame 21 and a lower frame 22, and an upper frame 21 and a lower frame 22.
1 is supported on a lower frame 22 by a rotation hinge 23 so as to be openable and closable.

Around the photoreceptor drum 1, which is an image carrier, there are an eraser lamp 13 for erasing the surface potential of the photoreceptor drum 1, a charger 11 for charging the surface of the photoreceptor drum 1, and a charger 11 for printing. An LED head 2 as an exposure means that forms an electrostatic latent image on the photoreceptor drum 1 based on data, a developer 8 that attaches toner to the electrostatic latent image on the photoreceptor drum 1 and develops it, and a photoreceptor drum. A transfer charger 14 for transferring the image of No. 1 onto a sheet of paper and a cleaning blade 9 for scraping off toner remaining on the drum surface after transfer are arranged.The transfer charger 14 is installed on the lower frame 22, and an eraser lamp 13. Charger 11, LED head 2.
Eight developing units 8 are installed in the upper frame 21.

In this embodiment, a photosensitive drum 1 is rotatably installed in a process cartridge 12 that is removably incorporated into an upper frame 21, and a charger 11, a cleaning blade 9, and a waste toner storage section 10 are also installed. 2
1 is provided with a guide groove 21a for guiding the process force nitride 12 in a direction perpendicular to the axis of the rotating shaft 1a of the photoreceptor drum 1 near the process where the process cartridge 12 is finally connected. Fit the end of the rotating shaft 1a of the drum 1 into the cartridge 1a, and then remove the process cartridge 1.
2 is attached to and detached from the upper frame 21. 12a is a handle for operating the process cartridge 12.

As the photosensitive drum 1, which is an image carrier, rotates in the direction of the arrow, its surface sequentially undergoes the following steps (1) to (2). Namely.

■Disappearance of potential by the eraser lamp 13, ■Charging by the charger 11, ■Formation of an electrostatic latent image by the LED head 2, which is an exposure means, ■Development by the toner 24 of the developing device 8, ■Transfer paper by the transfer charger 14 (not shown) (1) Transfer of the toner image onto the drum surface; (2) Scraping off the waste toner 25 with the cleaning blade 9 of the toner remaining on the drum surface after the transfer are repeated to continuously transfer the image onto the transfer paper.

In this embodiment, the LED head 2 is used as the exposure means as described above, but this has a structure in which an image by the internal LED array 3 is formed on the photoreceptor drum 1 through the short focus lens array 2. It is necessary to strictly control the accuracy of the distance between the array 3 and the photosensitive drum 1 surface.

In order to manage this distance accuracy, in this embodiment, FIG.
As shown in FIG. 2, the LED head 2 is guided by a guide shaft 6 whose axis is directed toward the center of the drum, and
While biasing the head 2 toward the photoreceptor drum 1 with a spring 7, the guide roller 5, which is arranged on an axis parallel to the axis of the photoreceptor drum 1 and connected to the LED head 2, is moved toward the surface of the photoreceptor drum 1. The structure is such that it comes into contact with the This part is shown in the perspective view of FIG. 2. According to this method, the dimensions of the inner diameter and outer diameter of the guide roller 5 are managed, and the mounting position of the shaft 26 that supports the guide roller 5 and the short focus lens array 4 and the LED array are controlled. By controlling the distance 3, the guide roller 5 is always in contact with the photoreceptor drum 1 due to the spring 7, so even in an extreme case where the photoreceptor drum 1 is deformed, the light from the LED array 3 will not reach the photoreceptor drum 1. It becomes possible to form an image correctly on the surface of the drum 1.

However, when the LED head 2 is supported in this way.

In order to avoid unnecessary scratches on the surface of the photoreceptor drum 1 due to the guide roller 5, consideration must be given to the structure of the underwear attached to the main body of the photoreceptor drum 1. Therefore, in this embodiment, as described above, at least while the guide roller 5 and the photoreceptor drum 1 are in contact with each other, the photoreceptor drum 1 is guided and moved by the guide groove 21a in a direction perpendicular to its axis. The force applied when the photosensitive drum 1 and the guide roller 5 come into contact is absorbed by the rotation of the guide roller 5, thereby preventing damage to the surface of the photosensitive drum 1. In addition, in this embodiment, the apparatus is divided into two parts as shown in FIG. 3, and the upper frame 21 of the two parts is lowered by a hinge 23 so that when the transfer paper becomes jammed inside the apparatus, it can be easily cleared. An upper frame 21 and a lower frame 2 that are supported on a frame 22 so as to be openable and closable, and that open and close around a 5-inch 23.
The paper conveyance mechanism is installed separately in 2 and 2, respectively. That is, a guide 28 and a roller 27 are installed on the upper frame 21,
A guide 16. which is paired with a guide 28 is attached to the lower frame 22. Roller 15 paired with roller 27. Guide 17. Fuser 18.
Discharge roller 19. Install the stacker 20. Therefore, when the upper frame 21 and lower frame 22 of the device are opened around the hinge 23, the guides 28 and 16, the rollers 15 and 27
．． Photosensitive drum 1, transfer charger 14, and guide 17
It is divided into upper and lower sections for easy access. Further, in the open state of the apparatus, the process cartridge 12 supporting the photoreceptor drum 1 is pulled out in the direction shown by the arrow in FIG. 4 in a direction perpendicular to the axis of the photoreceptor drum 1.

(Embodiment 2) Although an embodiment in which the LED head 2 is used as an exposure means has been described above, an embodiment in which a liquid crystal shutter is used as the primary is shown in FIG. 5. A lamp 30 and a light guide lens 31° liquid crystal shutter array 29 are incorporated, and here also the liquid crystal shutter array 2
In order for the image obtained by 9 to be properly focused on the surface of the photoreceptor drum 1 through the short-focus Rondo type lens array 4, the distance between the liquid crystal shutter array 29 and the surface of the photoreceptor drum 1 must be set as in the first embodiment. It is necessary to maintain accuracy depending on the method.

This method is shown in FIG. Since the lamp 30 for the liquid crystal head cannot be used because the light intensity at both ends is unstable, the lamp 30 has a shape that protrudes further in the direction of the drum axis than the guide shaft 6, as shown in the figure, and therefore the length of the guide shaft 6 is The head 3 has the same structure as that shown in FIG. 2 except that it is shorter than that of FIG. 2 of Embodiment 1.
It is possible to support 2.

(Embodiment 3) Next, FIG. 7 shows a different embodiment of the mechanism for guiding the head.

In this example, the LED head 2 is moved along with the arm 33 attached to a part thereof, and the fulcrum guide part 33a of the arm slides on the outer circumference of the guide shaft 34.

It can rotate about the axis of the guide shaft 34.

A portion 34a of the guide shaft 34 is fixed to a side wall 36 of the main body of the image forming apparatus, one end 35b of a screw spring 35 wound around the outer circumference of the guide shaft is fixed to the side wall 36, and the other end 35a is fixed to the arm of the LED head. 33, the LED head 2 is urged in the direction of the photosensitive drum 1, producing the same effect as in the embodiment described above. It is clear that this embodiment can also be applied to a case where a liquid crystal head is used as an exposure means.

〔Effect of the invention〕

As explained above, the present invention supports the tram by maintaining the distance between the exposure means, which is guided and urged in the direction of the drum, which is an image bearing member, and the drum by a guide roller disposed on a shaft parallel to the drum axis. By making the direction in which the frame is attached to and removed from the apparatus main body perpendicular to the drum axis, it is possible to easily maintain the relative positional accuracy of the drum and exposure means while minimizing the number of openings in the apparatus, making it possible to clear jammed paper in the apparatus, The process cartridge can be attached and detached by dividing or opening one device, which has the effect of realizing a device with good operability and a simple structure.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of one embodiment of the present invention, Fig. 2 is a perspective view of the LED head holding part of Fig. 1, and Fig. 3 is a state in which the device is divided and opened in the embodiment of Fig. 1. 4th longitudinal sectional view showing
The figure is a longitudinal sectional view showing the attachment and detachment of the photosensitive drum support frame in the state shown in Fig. 3, Fig. 5 is a longitudinal sectional view of the second embodiment, and Fig. 6 is a perspective view showing the liquid crystal head holding part of Fig. 5. 7 are perspective views of the third embodiment. 1... Photosensitive drum, 2... LED head, 3...
・LED array, 4... Short focus Rondo lens array, 5... Guide roller, 6... Guide shaft, 7
... Spring, 8... Developing device, 9... Cleaning blade, 10... Waste toner storage section, 11...
Charger, 12... Photoreceptor support frame, 12a.
...Photoconductor support frame handle, 13...Eraser lamp,
14... Transfer charger, 15... Feed roller, 16.17... Paper guide, 18... Fixing device, 1
9... Discharge roller, 20... Stacker, 21...
Upper half of the device. 22... Lower half of the device, 23... Rotating hinge, 24...
... Toner, 25 ... Waste toner, 26 ... Shaft, 27 ... Feed roller, 28 ... Paper guide,
29...Liquid crystal shutter array.

Claims (1)

[Claims] (1) In an image forming apparatus that includes a process cartridge that incorporates an image carrier and an image forming process device disposed close to the image carrier, the process cartridge is removably attached to the main body of the image forming apparatus. , an exposure means that is set in a direction perpendicular to the axis of the image carrier at least in the vicinity of the process where the process cartridge is finally connected to the apparatus main body, and forms an electrostatic latent image on the image carrier; means for movably guiding the exposure means in the direction of the image carrier; means for biasing the exposure means in the direction of the image carrier; and at least one guide roller disposed on an axis parallel to the image forming apparatus, and at least one guide roller disposed at a position where the biasing means abuts the image carrier when the process cartridge is mounted on the apparatus main body. Device.