JPH0728377A - Image forming device - Google Patents

Abstract

PURPOSE:To make the exchangeability of a photoreceptor unit, a developing device, etc., caused by their service lifes easy and to always/stably obtain an excellent image by preventing irregularities in an image density due to a defect in the precision of the developing gap between the photoreceptor drum and a developing sleeve and soiling inside a device main body due to the spillage of toner. CONSTITUTION:The image forming device is composed of the photoreceptor unit 1a including at least, the photoreceptor drum 1 carrying a latent image and a cleaning device 2 coming into slidable contact with the photoreceptor drum 1 and freely attachably/detachably fitted to the device main body 40, the developing device 7 having the developing sleeve 6 arranged opposite to the photoreceptor drum 1 and freely turnably held on the device main body 40 and an opening/closing door 24 which is freely turnably attached to the device main body 40 and can open/close the device main body 40, to attach/detach the photoreceptor unit 1a, a contact/separate member with the exerted pressure 15 contacting separating from the developing device 7 with the exerted pressure, linked with the opening/closing actions of the opening/closing door 24 is provided and the developing device 7 is turned by the contact/separate member with the exerted pressure 15, to set the developing gap between the photosensitive drum 1 and the developing sleeve 6 and release the setting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine or an LED printer having a detachable photoconductor unit.

[0002]

2. Description of the Related Art In a copying machine or printer using this type of electrophotographic technique, as shown in FIG. 4, a photosensitive drum 51, a cleaning device 52, a developing device 57, etc. are integrated in order to improve exchange maintenance. When the consumables are replaced as a process cartridge that has become a simplified process cartridge, the process cartridge is integrally attached to and detached from the apparatus body. However, in this method, the replacement life is determined by the toner capacity stored in the developing device 57 or the waste toner recovery capacity in the cleaning device 52, and moreover, the size and weight of the device are required to be reduced, so that the capacities are naturally limited. Existed.
In other words, the process cartridge components have to be replaced together due to the limit of toner capacity even though there is still a margin of service life, and there was a feeling that the running cost was expensive. Reference numeral 53 is a charging device, 55 is an exposure device, 58 is a fixing device, and 59 is a transfer device.

Therefore, in recent years, as shown in FIG. 5, by splitting the photoconductor unit 61a including the photoconductor drum 61 and the developing device 67, the replacement life of the photoconductor unit 61a is determined by the waste toner recovery capacity of the cleaning device 62 or the photoconductor. By setting the deterioration life of the drum 61 and setting the life of the developing device 67 as the deterioration life of the toner capacity or the developer holding means (hereinafter referred to as a developing sleeve) 66, for example, the development is performed for three replacements of the photoconductor unit 61a. By changing the device 67 only once, the running cost is reduced as compared with the process cartridge system. The photoconductor unit 61a and the developing device 67 can be attached to and detached from the main body by positioning the photoconductor unit 61a and the developing device 67 into unit guide grooves 77 and 76 formed integrally with a unit fixing member 75 rotatably held in the main body of the device. The guide members 78 and 79 are fixedly guided.
That is, the setting of the developing gap A between the photosensitive drum 61 and the developing sleeve 66 is determined by the distance between the unit guide grooves 77 and 76. In addition, 68 is a fixing device, 69 is a transfer device, and 70.
Is a paper feed roller.

To prevent the unit from rising when a drive is connected to each unit, the user manually operates a lifting prevention device (not shown) provided on the unit fixing member 75. On the contrary, when the unit comes to the end of its replacement life and the unit is removed, the lifting prevention device must be manually released. FIG. 6 shows a photoconductor unit 61a and a developing device 67.
It shows that the jammed paper is removed by opening and closing the unit fixing member 75 that fixes the paper.

[0005]

However, as shown in FIGS. 5 and 6, the photoconductor unit 61a and the developing device 67 are divided, and the positioning guide groove 77 of the unit fixing member 75 provided in the main body of the device is divided. The developing gap A between the photoconductor drum 61 and the developing sleeve 66 is set via dimensional precision of the unit fixing member 75, the positioning reference members 78 and 79 of the photoconductor unit 61a and the developing device 67, and the unit fixing member 75. Accumulated errors such as rattling of the guide grooves 77 and 76 have a great influence, and the guide grooves 77 and 76 largely deviate from the predetermined developing gap A in the axial direction of the photosensitive drum 61. For this reason, a density difference occurs in the image on the photosensitive drum 61 in the axial direction, or toner cannot pass in the area narrower than the predetermined developing gap A, and toner accumulation occurs, which eventually causes toner on the transfer or inside the apparatus main body. It was causing a spill.

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to solve the above-mentioned problems, and facilitates the replaceability due to the life of the photoconductor unit, the developing device, etc., and the poor development gap accuracy between the photoconductor drum and the developing sleeve. It is an object of the present invention to provide an image forming apparatus which can prevent image density unevenness due to the above and stains in the apparatus main body due to toner spilling and can always obtain a good image stably.

[0007]

An image forming apparatus according to a first aspect of the present invention is provided with a pressing / separating member that presses and separates from the developing device in conjunction with the opening / closing operation of an opening / closing door, and the developing device is rotated by the pressing / separating member. It is characterized in that the developing gap between the photosensitive drum and the developing sleeve is set / released by moving the photosensitive drum.

An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, in which the pressing / seating member is swingably provided with respect to the opening / closing door. An image forming apparatus according to a third aspect is the image forming apparatus according to the first aspect, wherein a roller member is concentrically and rotatably provided on the rotation axis of the developing sleeve, and the roller member presses the non-image portion of the photosensitive drum. The development gap is set by the contact.

[0009]

According to the structure of the present invention, when the opening / closing door is closed, the pressing / separating member comes into contact with the developing device to rotate the developing device to set the developing gap, and when the opening / closing door is opened, the pressing / separating member is pressed. The contact member is separated from the developing device and the developing device is rotated in the opposite direction to release the developing gap. As described above, since the pressing / separating member is pressed / separated to / from the developing device in conjunction with the opening / closing operation of the opening / closing door, the developing gap between the photosensitive drum and the developing sleeve is automatically set / released. It is possible to prevent image density unevenness due to poor gap accuracy and stains inside the apparatus main body due to toner spill, and always obtain a good image in a stable manner. Further, since the photoconductor unit and the developing device are separated, the life of the developing device can be made equal to the life of the main body of the device by optimizing the surface roughness of the developing sleeve, for example. And toner replenishment only. Therefore, it is also excellent in user maintainability.

When the developing gap is set, the developing gap accuracy is achieved by the roller member concentrically and rotatably arranged on the rotary shaft of the developing sleeve pressingly contacting the non-image portion of the photosensitive drum. The intervening member for securing is minimized, and an accurate development gap can always be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. This image forming apparatus includes a photoconductor unit 1
a, a developing device 7, an opening / closing door 24, and the like. As shown in FIGS. 1 and 2, the photoconductor unit 1a is detachably attached to the apparatus main body 40, and the photoconductor drum 1 carrying a latent image, the charging device 3 for uniformly charging the photoconductor drum 1,
It comprises a cleaning device 2 which is in sliding contact with the photosensitive drum 1 and removes residual toner on the photosensitive drum 1 after the toner image is transferred onto the transfer material 9. The cleaning device 2 is disposed substantially at the top of the photosensitive drum 1, and has a cleaning blade 2a, a squeeze sheet 2 made of urethane rubber sheet or the like.
b, a spiral residual toner conveying means 2c. The residual toner accumulated in the cleaning device 2 is sequentially transferred to the photoconductor unit 1 by the residual toner conveying means 3c.
The toner is sent to a waste toner storage unit (not shown) integrally arranged on the side surface of a.

As shown in FIG. 1, the photoconductor unit 1a is supported by the apparatus body 40 while being guided in the direction of arrow D along the guide groove 33 of the apparatus body 40. At this time,
The drive means of the photosensitive drum 1 and the drive transmission means 11 provided in the apparatus body 40 are connected. When the drive is transmitted to the photoconductor drum 1, the driving force acts in a direction to prevent the photoconductor unit 1a from rising, and the photoconductor unit 1a is firmly held at a predetermined position. An exposure device 5 forms an electrostatic latent image on the photosensitive drum 1.

The developing device 7 has a developing sleeve 6 arranged so as to face the photosensitive drum 1, and converts the electrostatic latent image on the photosensitive drum 1 into a toner image. That is, in FIG. 2, the toner charged to the same polarity as the electrostatic latent image by the developing device 7 contacts the photoconductor drum 1 rotating in the direction of the arrow, and the photoconductor (not shown) from the exposure device 5 causes the photoconductor to rotate. A developing bias potential is applied to the developing sleeve 6 so as to be attracted by the charge of the electrostatic latent image formed on the drum 1. The toner image on the photosensitive drum 1 is applied with a voltage applying device (not shown) at the transfer portion.
The image is transferred to the transfer material 9 by the transfer device 13 connected to the transfer material. The residual toner on the photoconductor drum 1 after the transfer is removed by the cleaning device 2 and sent to the initialization process of the photoconductor drum 1 of the charge removing device 4, and the above process is repeated again.

A support shaft 8 is integrally formed on the side surface of the developing device 7, and the support shaft 8 is rotatably fixedly held on the main body 40 of the device. Then, as shown in FIG. 1, when the photoconductor unit 1a is removed from the apparatus main body 40, the developing sleeve 6 is rotated in the direction of arrow B by its own weight. Further, elastic spring members 32 are attached to both ends of the bottom of the developing device 7 so as to alleviate the turning force in the arrow B direction.

Further, as shown in FIG. 3, the photosensitive drum 1
A developing gap A between the developing sleeve 6 and the developing sleeve 6 is set by the roller member 20. That is, the roller members 20 are rotatably arranged concentrically at both ends of the rotation center shaft 22 of the developing sleeve 6. The roller member 20 has a radius larger than the radius of the developing sleeve 6 by a predetermined developing gap A, and the developing gap A is set by the roller member 20 being in direct pressure contact with the non-image portion 21 of the photosensitive drum 1. .

The open / close door 24 is supported by the rotation support shaft 34 and is opened / closed when the photoconductor unit 1a is attached or detached or when jammed paper is removed. Pressing / separating members 15 which are swingably held are arranged at both ends of the opening / closing door 24, and the pressing / separating member 15 presses the outer edge 19 of the developing device 7 in conjunction with the closing operation of the opening / closing door. The developing device 7 is pushed up in the direction of arrow C. In addition,
In this case, the pressing / separating member 15 is swingably arranged via the guide member 16 and the pressure spring 17.

Reference numeral 31 denotes a paper feed tray on which the transfer material 9 is placed, 1
Reference numeral 0 denotes a paper feed roller that separates and feeds the transfer materials 9 on the paper feed tray 31, sheet by sheet, 12 a fixing device that fixes the toner image transferred to the transfer material 9, and 30 receives the discharged transfer material 9. It is a paper tray. The transfer material 9 is conveyed from bottom to top as shown by the chain double-dashed line. Next, the operation of this image forming apparatus will be described. As shown in FIG. 1, when the opening / closing door 24 is opened to attach / detach the photoconductor unit 1a, the developing device 7 is rotated in the arrow B direction as described above. When the photoconductor unit 1a is mounted and the opening / closing door 24 is closed from this state, the pressing / separating member 15 presses the outer edge 19 of the developing device 7 and the developing device 7 as shown in FIG.
In the direction of arrow C. Along with this, the roller member 20
The developing gap A is set by directly pressing and contacting the non-image portion 21 of the photosensitive drum 1. Further, when the opening / closing door 24 is opened, the pressing / separating member 15 is separated from the developing device 7, the developing device 7 is rotated in the direction of arrow B by its own weight, and the setting of the developing gap A is released.

In this embodiment, the pressing / separating member 15 presses and contacts the developing device 7 in conjunction with the opening / closing operation of the opening / closing door 24,
Along with this, the developing member A is set by pressing the roller member 20 against the non-image portion of the photosensitive drum 1, so that the image density unevenness due to the poor accuracy of the developing member gap and the inside of the apparatus main body 40 due to toner spillage are contaminated. It is possible to prevent and always obtain a good image stably. In addition, the photoconductor unit 1
Since a and the developing device 7 are separated, for example, by making the surface roughness of the developing sleeve 6 about 5 μm and optimizing the toner composition, the life of the developing device 7 can be made equal to the life of the device main body 40. The consumables can be replaced only by replenishing the photoconductor unit 1a and the toner, which is excellent in user maintenance.

The pressing / separating member 15 may be provided in addition to the opening / closing door 24.

[0020]

According to the image forming apparatus of the present invention, when the opening / closing door is closed, the pressing / separating member comes into contact with the developing device, and the developing device is rotated to set the developing gap. When opened, the pressing / separating member separates from the developing device, and the developing device is rotated in the opposite direction to release the developing gap. As described above, since the pressing / separating member is pressed / separated to / from the developing device in conjunction with the opening / closing operation of the opening / closing door, the developing gap between the photosensitive drum and the developing sleeve is automatically set / released. It is possible to prevent image density unevenness due to poor gap accuracy and stains inside the apparatus main body due to toner spill, and always obtain a good image in a stable manner. Further, since the photoconductor unit and the developing device are separated, the life of the developing device can be made equal to the life of the main body of the device by optimizing the surface roughness of the developing sleeve, for example. And toner replenishment only. For this reason,
Excellent user maintenance.

Further, when the developing gap is set, the developing gap accuracy is achieved by the roller member, which is concentrically rotatably arranged on the rotary shaft of the developing sleeve, presses and contacts the non-image portion of the photosensitive drum. The intervening member for securing is minimized, and an accurate development gap can always be obtained.

[Brief description of drawings]

FIG. 1 is a sectional side view of a state in which a photoconductor unit is removed according to an embodiment of the present invention.

FIG. 2 is a sectional side view of a state in which a photoconductor unit is mounted in FIG.

FIG. 3 is an explanatory diagram of developing gap setting.

FIG. 4 is a conceptual diagram of a conventional example.

FIG. 5 is a partially exploded conceptual view of another conventional example.

6 is an explanatory diagram at the time of maintenance in FIG.

[Explanation of symbols]

 1a Photoreceptor Unit 1 Photoreceptor Drum 2 Cleaning Device 6 Developing Sleeve 7 Developing Device 15 Pressing / separating Member 20 Roller Member 24 Opening / Closing Door 40 Device Main Body

Claims (3)

[Claims] 1. A photoconductor unit detachably attached to a main body of the apparatus, the photoconductor unit including at least a photoconductor drum carrying a latent image and a cleaning device slidably contacting the photoconductor drum, and a photoconductor unit opposed to the photoconductor drum. Developing device having a developing sleeve rotatably held in the device body, and an opening / closing door rotatably attached to the device body and capable of opening and closing the device body for attachment and detachment of the photoconductor unit. An image forming apparatus comprising: a pressing / separating member that presses / separates to / from the developing device in conjunction with the opening / closing operation of the opening / closing door, and the developing device is rotated by the pressing / separating member. An image forming apparatus which sets and releases a developing gap between a photosensitive drum and the developing sleeve. 2. The image forming apparatus according to claim 1, wherein the pressing / seating member is provided swingably with respect to the opening / closing door. 3. The developing gap is set by concentrically and rotatably providing a roller member on the rotary shaft of the developing sleeve, and pressing the roller member against the non-image portion of the photosensitive drum. Image forming device.