JPH06250521A - Image forming device - Google Patents

Abstract

PURPOSE:To attain downsizing of the device sharply while avoiding complication of the device constitution even when a cleaning blade is arranged, by feeding residual toner removed by the cleaning blade to the toner replenishing side situated on the opposite side to a developing sleeve while sandwiching an agitating member between them. CONSTITUTION:Residual toner sticking on a photoreceptor 14 after transfer is scraped off by a cleaning blade 22, and is stored in a storage part 23 after paper powder is removed by implanted hairs 29 while dropping sliding on the blade surface. Every time a compounding ratio of a carrier and toner of a developer layer sticking on a developing sleeve 30 is decreased, a sponge roller 38 is rotated together with a replenishing roller 31, and fresh toner of a necessary quantity from which a return quantity of residual toner is subtracted is supplied to the storage part 23 on the developing container 25 side. It is also supplied to the developer storage part 23 of an agitating roller 32 by a replenishing roller 31, and a developer maintained always in a proper mixing ratio is supplied to the developing sleeve 30 side while being agitated and mixed by the agitating roller 32.

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 using an LED head, and in particular, the LED head is arranged on the inner peripheral surface side or the outer peripheral surface side of the photoconductor drum, and the LED head is used on the photoconductor drum. The present invention relates to an image forming apparatus capable of developing an exposure image formed on a sheet using a multi-component developer.

[0002]

2. Description of the Related Art Conventionally, process means such as exposure, development, transfer, cleaning (removal of residual toner), charge removal, and charging are arranged on the outer peripheral surface of a photosensitive drum to form an image by a predetermined electrophotographic process. Image forming apparatuses based on the so-called Carlson process are well known.

Further, a light-transmitting conductive layer and a photoconductor layer are laminated on a cylindrical light-transmitting support to form a photosensitive drum, and an optical output corresponding to image information is generated in the drum. A toner carrier disposed inside the exposing means (for example, an LED head) for forming a latent image on the photoconductor layer through the focusing lens of the light output of the exposing means at the same time or immediately thereafter. An image forming apparatus configured to transfer the latent image to a toner image (development) through a body, and then transfer the toner image onto a recording sheet through a transfer roller or other transfer means (Japanese Patent Laid-Open No. 153957/58). ) Is also known.

In the former image forming apparatus, in order to remove the residual toner remaining on the toner after the transfer, a cleaning blade whose tip is in contact with the peripheral surface of the drum is provided, and the residual toner is removed through the blade. ing.

On the other hand, in the latter image forming apparatus, a developer sliding area is provided between the photosensitive drum and the developing sleeve without providing an independent charging device, and charging, exposure and development are performed through the sliding area. However, even in this type of apparatus, particularly when a multi-component developer including a carrier and a toner is used, when the residual toner is returned into the rubbing area, Due to the difference in the conductive resistance of the carrier, the conductive resistance in the rubbing area changes, so that the photosensitive drum cannot be charged smoothly and the image quality is likely to be adversely affected. Therefore, it is preferable that a cleaning blade is also provided in the above apparatus to remove the residual toner.

[0006]

However, the provision of the cleaning blade requires the provision of a residual toner recovery mechanism, a recovery container, etc., which tends to complicate the apparatus configuration and increase the size thereof. Further, there is also a structure in which the residual toner removed by the cleaning blade is returned to the toner container side. However, even in such a structure, not only a return mechanism for returning the toner to the container side is required, but also the residual toner is removed. Since it is once charged, it is easy for toner to accumulate if it enters the toner container as it is. Further, if the toner is directly put in the developing container, the toner concentration may change, especially when a multi-component developer composed of carrier and toner is used.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus capable of achieving a significant size reduction while avoiding a complicated apparatus configuration even when the cleaning blade is arranged. Another object of the present invention is to take a structure for returning the residual toner to the developing container side, but does not require a returning mechanism for returning the residual toner to the container side, and the toner pool and the toner concentration can be accurately controlled. An object is to provide an image forming apparatus.

[0008]

In order to achieve such a technical object, the invention according to claim 1 uses an LED as an exposing means.
The present invention relates to a device using a head, and particularly to any of the Carlson type devices in which the LED insertion device in which the LED head is inserted in the photosensitive drum is also provided with the LED head on the outer peripheral surface side of the photosensitive drum. In addition, it is applied to an apparatus using a multi-component developer composed of a carrier and a toner, and is characterized in that the development covers both the upper and lower sides of the photosensitive drum with the exposure position sandwiched therebetween. A container is provided, a cleaning blade for removing residual toner adhering to the peripheral surface of the photosensitive drum after transfer is provided in the internal space above the exposure position, and a carrier and toner are provided at the bottom of the container below the exposure position. An agitating member for agitating is provided so that the residual toner removed by the cleaning blade can be introduced to the toner replenishing side located on the opposite side of the developing sleeve with the agitating member interposed therebetween. It is characterized in that form. In this case, it is preferable to dispose a toner concentration detection sensor for detecting the toner concentration in the developing container at a position facing the developing sleeve, and it is more preferable to replenish the toner from the toner container side together with the residual toner that has been fed to the replenishment side. It is preferable that a storage section for temporarily storing the stored new toner is provided, and the toner can be appropriately replenished to the stirring member side from the storage section based on a signal from a toner concentration detection sensor for detecting the toner concentration. Further, it is preferable that the cleaning blade is slanted toward the toner replenishment side so that residual toner can slide off along the upper surface of the blade, and paper dust removing means is provided on the upper surface of the blade.

The invention described in claim 5 is an image forming apparatus in which an LED head is arranged on the outer peripheral surface side of a photosensitive drum, and is applicable to both a one-component developer and a two-component developer. A characteristic is that a developing container that covers the upper and lower sides of the photosensitive drum is sandwiched between the exposing positions, and the developing container is isolated from the peripheral surface of the photosensitive drum facing the exposing position. There is provided a recessed space, and the LED head is disposed in the space. In this case, a cleaning blade for removing the residual toner adhering to the peripheral surface of the photosensitive drum after the transfer is arranged in the space inside the container above the concave space, and a stirring member for stirring the carrier and toner is arranged at the bottom of the container below the concave space. It is preferable that the residual toner removed by the cleaning blade can be introduced to the stirring member side through the inner space of the container located on the back side of the recessed space.

[0010]

According to the first aspect of the present invention, since the cleaning blade is provided inside the developing container and above the inside of the developing container, no special recovery mechanism or return mechanism is required, and the action of gravity is achieved. It can be easily returned to the bottom of the developing container. Further, since the residual toner removed by the cleaning blade can be introduced to the toner replenishing side located on the opposite side of the developing sleeve with the agitating member interposed, the fresh toner and the residual toner are sufficiently agitated by the agitating member and uniformly charged. In this state, the toner can be supplied to the developing sleeve side, which eliminates variations in charging, and there is no room for toner accumulation. Further, since the cleaning blade is inside the developing container, there is no room for toner contamination when scraping the residual toner.

In this case, if a toner concentration detecting sensor for detecting the toner concentration in the developing container is provided at a position facing the agitating member as in the prior art, the residual toner and the fresh toner are not sufficiently agitated. The toner density varies depending on the amount of returned toner, and the density cannot be detected accurately. Therefore, in the second aspect of the invention, a toner concentration sensor is provided at a position facing the developing sleeve so that the developer having a uniform concentration after being stirred by the stirring member can be detected. In this case, a storage section is provided for temporarily storing the residual toner supplied to the replenishment side and the new toner replenished from the toner container side, and based on a signal from the toner concentration detection sensor for detecting the toner concentration, the storage section is provided. It is preferable that toner can be appropriately supplied to the stirring member side. Further, in the present invention, since the paper dust removing means is provided on the upper surface side of the cleaning blade, it is possible to remove the paper dust before the residual toner is slid along the upper surface side of the blade and is put into the container. .

With the above construction, the developing container is disposed so as to extend vertically above and below the exposure position. In other words, a so-called laser is used to allow the residual toner to pass over the exposure position. It cannot be applied to a device such as a printer in which the exposure means performs beam scanning on the bus. For example, as shown in JP-A-1-197251, there is an apparatus having a cleaning blade on the upper side and a developer storage tank on the lower side across the exposure position. Since the beam scanning is performed on the photoconductor drum bus, the cleaning blade and the developer storage tank are divided by the beam scanning, and it is impossible to integrate the blade and the developer storage tank.

Therefore, in the invention according to claim 5, L
The ED head is limited to an image forming apparatus arranged on the outer peripheral surface side of the photoconductor drum, and in order to prevent toner from adhering to the head, both upper and lower surfaces of the photoconductor drum are sandwiched by the exposure position. A developing container that encloses the developing container is provided, and a concave space separated from the developing container is provided on the peripheral surface of the photosensitive drum facing the exposure position, and the LED head is provided in the space. In this case, a cleaning blade for removing the residual toner adhering to the peripheral surface of the photosensitive drum after the transfer is arranged in the space inside the container above the concave space, and a stirring member for stirring the carrier and toner is arranged at the bottom of the container below the concave space. In addition, the residual toner removed by the cleaning blade can be introduced into the stirring member side through the inner space of the container located on the back side of the recessed space, thereby smoothly achieving the action of the first invention. obtain.

[0014]

Embodiments of the present invention will now be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely examples, unless otherwise specified. Not too much. Figure 1
2 is a schematic diagram showing the configuration of the printer according to the embodiment of the present invention. The housing 1 used in this apparatus has an upper surface paper ejection portion 2 which is inclined upward to the left side from the central portion on the upper surface side.
In addition, the ridge 3 is formed on the right side wall so that the fulcrum 3 can be raised and lowered about the fulcrum 3 at the lower end, and when it is laid down substantially horizontally with a slight upward inclination angle, the position is locked by the locking portion. The recording paper placing portion 5 is formed. Then, a positioning portion 5a for the leading end of the recording paper, which is formed by raising the back end of the placing portion 5 into a key shape, is provided, and a paper feed roller 11 is pivotally supported on the upper end of the positioning portion 5a. A substantially arc-shaped recording paper conveyance path 10 is formed toward the upper surface paper ejection unit 2 side.
A paper detection sensor 12, a transfer roller 13, a photoconductor drum 14, a fixing roller 15, and a paper discharge roller 16 are arranged in this order along the recording paper conveyance direction of the conveyance path 10, and transfer is performed with the photoconductor drum 14 interposed therebetween. The developing unit 6 is arranged in the space above the mounting portion 5 located on the opposite side of the roller 13. still,
In this embodiment, the registration roller is eliminated, and the paper feed roller 11 and the paper detection sensor 12 have a registration function. Further, a is a power unit.

Next, the respective members will be described in detail. The paper discharge unit 2 is configured to be openable around a fulcrum 2a provided at the upper left end, and the toner container 20 attached to the developing unit 6 can be taken out by the opening. A positioning portion 5a for aligning the recording papers is provided on the front end side of the placing portion 5 described above.
The friction pad 5b is provided on the upper surface side of the starting end of the conveying surface which contacts
And the paper feed roller 11 is arranged so as to come into contact with both the friction pad 5b and the recording paper placing portion 5.

As the transfer roller 13, a conductive roller is used in order to improve transfer efficiency, a transfer bias having a polarity opposite to the charging potential of the toner is applied, and the transfer roller 13 is evenly pressed against the peripheral surface of the photosensitive drum 14 so as to contact the drum. It is configured to be rotatable in synchronization with 14. As is well known, the photosensitive drum 14 includes a transparent conductive layer, a photoconductive layer, and a transparent conductive layer on the transparent support from the inner surface side.
And the surface layer is formed by being laminated. The LED unit 7 is inserted in the drum 14, and its image forming position is set downward so that it can face the developing sleeve 30. The photosensitive drum 14 is configured to be rotatable counterclockwise.

The LED unit 7 is composed of a converging lens array (trade name: SELFOC lens) arranged on a printed board on which LED chip rows and the like arranged in one row along the drum axis direction are mounted. Further, these are integrally held by a head block, and data of pixel information for one scanning line is output while the LED chip is time-divisionally or statically driven.

The developing unit 6 has a toner container 20 containing replenishment toner and an L-shaped step portion 21 on which the toner container 20 is detachably mounted. The developing container 25 is housed therein, and the cleaning container 22 for removing residual toner, the residual toner scraped by the cleaning blade 22 and the fresh toner replenished from the toner container 20 side are temporarily stored in the developing container 25. The storage section 23, the replenishing roller 31 provided at the bottom of the reserving section 23, the agitating roller 32 disposed at the bottom of the developing container 25 at the outlet opening of the replenishing roller 31, and the agitating roller 32 and the photosensitive drum 14 are faced to each other. The toner concentration sensor 3 is provided on the developing sleeve 30 including the fixed magnet assembly 33, and on the bottom of the container facing the developing sleeve 30. There are people disposed husband.

As shown in FIG. 2, 35 is a doctor blade, 36 is a partition for partitioning a space below the cleaning blade 22 on the upstream side of the exposure position, and the charging carrier and the magnetic brush roller 37 are housed in the partition 36. The rotation is performed by the magnetic brush roller 37 so that the carrier is rubbed on the surface of the developer to be charged. The developing container 25 is arranged so as to cover the peripheral surface of the photosensitive drum 14 on both upper and lower sides of the exposure position, and the cleaning blade 22 is provided on the peripheral surface of the photosensitive drum 14 above the exposure position. With the blade 22 slantingly inclined toward the storage portion 23 side so that the residual toner can slide off along the upper surface side of the blade 22, and the upper surface of the blade 22 is flocked with 29 to reverse the paper dust. It is configured so that paper dust can be removed by charging it to a potential.

The photosensitive drum 14 at the upper end of the developing container 25
A film-shaped mylar 28 is attached along the rotation direction of the photosensitive drum 14 at a position facing to prevent the toner from scattering. Between the toner container 20 and the developing container 25, a sponge roller 38 is provided in a slit opening 21a provided in the partition wall 21.
The rotation speed is set so that a required amount of fresh toner obtained by subtracting the amount of the residual toner returned based on the signal from the toner concentration sensor 34 can be supplied to the reservoir 23 on the side of the developing container 25.

The supply roller 31 has a sponge layer 39 on both sides.
And the replenishing roller 31 forms a carrier layer of the developer layer adhering to the developing sleeve 30 based on a signal from the toner concentration sensor 34.
The replenishing roller 31 is rotated each time the toner blending ratio (toner concentration) is lowered, and is constantly maintained at an appropriate blending ratio.

According to this embodiment, the surface of the photosensitive drum 14 is charged by the rubbing of the magnetic ears of the carrier formed on the magnetic brush roller 37, and then the LED unit 7 exposes the developing sleeve 30 at the same time. After being developed by the developer carried on the paper, the paper is transferred by the paper feed roller 11 and the paper detection sensor 12 to the recording paper fed in synchronism with the image start end via the transfer roller 13, and then by the fixing roller 15. After the image is fixed, the paper is ejected through the paper ejection roller 16.

On the other hand, the residual toner adhering to the photosensitive drum 14 after transfer passes through the filler at the upper end of the developing container 25 and is scraped off by the cleaning blade 22 to remove the paper dust by the flocking 29 while sliding off the blade surface. After being stored, it is stored in the storage unit 23. Each time the carrier / toner compounding ratio (toner concentration) of the developer layer adhering to the developing sleeve 30 decreases, the sponge roller 38 rotates together with the replenishing roller 31 and the required amount of freshness obtained by subtracting the amount of returning residual toner is reduced. While the toner is supplied to the reservoir 23 on the side of the developing container 25, the toner is further supplied to the developer reservoir 23 of the stirring roller 32 by the replenishing roller 3135, and is stirred and mixed by the stirring roller 32, and the developing sleeve 3
The developer always maintained in the proper mixing ratio is supplied to the 0 side.

FIG. 3 shows a schematic structure of a developing unit 6 of an LED printer in which an LED head is arranged on the outer peripheral surface side of a photosensitive drum 14 according to another embodiment of the present invention, and a magnetic brush roller 37 for charging is arranged. Storage space provided and developing sleeve 3
A recess space 40 that is separated from the developing container 25 by a partition wall 41 and opens toward the photoconductor drum 14 is provided between the mounting position of 0 and the LED unit 7 in the space. Further, on the back side of the partition wall 41, there is provided a storage portion 23 for temporarily storing the residual toner after scraped by the cleaning blade 22 and the fresh toner. According to this embodiment, the residual toner removed by the cleaning blade 22 is stored in the storage portion 23 located on the back side of the partition wall 36, and the pair of agitating rollers 32, 32 at the bottom of the developing container 25 via the supply roller 31. The LED unit 7 and the developing container 25 are guided to the side, and the LED unit 7 and the developing container 25 are separated from each other by the partition wall 36, so that toner does not adhere to the unit and a clear image can be formed. Is.

[0025]

As described above, according to the present invention, since the cleaning blade for removing the residual toner is arranged at an effective position in the developing container, the size of the apparatus can be greatly reduced while avoiding the complication of the apparatus configuration. Can be achieved. Further, according to the present invention, although the residual toner is returned to the developing container side, a returning mechanism for returning the residual toner to the container side is not required, and the toner accumulation and the toner concentration can be accurately controlled. According to the invention of claim 5, in particular, the LED head is mounted on the photosensitive drum 1.
4 In the case of a device arranged on the outer peripheral side, if the developing container is arranged so as to cover the upper and lower sides of the photosensitive drum 14 with the exposure position sandwiched, the problem of toner contamination of the LED head occurs. However, since the partition between the LED head and the developing container is isolated, toner does not adhere to the head and a clear image can be formed. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is an overall layout diagram according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a main configuration of the developing unit of FIG.

FIG. 3 is a cross-sectional view showing a main part configuration of a developing unit in an embodiment in which an LED head is arranged on the outer peripheral side of a photosensitive drum.

[Explanation of symbols]

 14 Photoreceptor Drum 25 Developing Container 7 LED Head 22 Cleaning Blade 32 Stirring Member 34 Toner Concentration Detection Sensor 30 Developing Sleeve 20 Toner Container 23 Reservoir 29 Paper Powder Removing Means 40 Recessed Space

Claims (6)

[Claims] 1. An LED head is arranged on an inner peripheral surface side or an outer peripheral surface side of a photoconductor drum, and an exposure image formed on the photoconductor drum by using the LED head can be developed using a multi-component developer. In the image forming apparatus configured as described above, a developing container that covers the upper and lower surfaces of the photoconductor drum with the exposure position sandwiched is provided, and the post-transfer photoconductor drum circumference is provided in the space inside the container above the exposure position. A cleaning blade for removing the residual toner adhering to the surface and a stirring member for stirring the carrier and the toner are provided at the bottom of the container below the exposure position, and the residual toner removed by the cleaning blade is sandwiched between the stirring members to develop. An image forming apparatus characterized in that it can be put into the toner replenishing side located on the opposite side of the sleeve. 2. An image forming apparatus according to claim 1, wherein a toner concentration detecting sensor for detecting the toner concentration in the developing container is arranged at a position facing the developing sleeve. 3. A storage section is provided for temporarily storing the residual toner supplied to the replenishment side and new toner replenished from the toner container side, and based on a signal from a toner concentration detection sensor for detecting toner concentration, The image forming apparatus according to claim 1, wherein the toner can be appropriately replenished from the reservoir to the stirring member side. 4. The cleaning blade is inclined obliquely toward the toner replenishment side so that residual toner can slide off along the upper surface of the blade, and paper dust removing means is provided on the upper surface of the blade. The image forming apparatus according to claim 1. 5. An image forming apparatus in which an LED head is arranged on the outer peripheral surface side of a photoconductor drum, and a developing container for covering the upper and lower surfaces of the photoconductor drum with the exposure position sandwiched therebetween is provided. An image forming apparatus characterized in that a concave space isolated from the developing container is provided on the peripheral surface of the photosensitive drum facing the exposure position, and an LED head is provided in the space. 6. A cleaning blade for removing the residual toner adhering to the peripheral surface of the photosensitive drum after transfer is provided in the inner space of the container above the recessed space, and an agitator for agitating carrier and toner at the bottom of the container below the recessed space. 6. The image according to claim 5, wherein a member is provided, and the residual toner removed by the cleaning blade can be introduced into the stirring member side through the inner space of the container located on the back side of the recessed space. Forming device