JPH03204669A - Developing device - Google Patents

Abstract

PURPOSE:To prevent a void, the degradation of toner, and contamination inside a machine, etc., even when printing is carried out on a small-sized sheet by dividing a developer carrier into plural ones in a shaft direction and independently or interlockingly driving each of them with a signal from a residual developer detecting means. CONSTITUTION:The developer carrier 4 is disposed between a developing part 3 and a developer housing part 1 and a developer in the developer housing part 1 is carried and supplied to the developing part 3. Further, the developer carrier 4 is divided into plural ones in the shaft direction, and each of them are independently or interlockingly driven with the signal from the residual developer detecting means 5. Therefore, when the developer is partly lacked in the longitudinal direction of the developing part 3, the residual developer detecting means 5 originates the signal to indicate the shortage of the developer. Only the developer carrier 4 corresponding to the lacking part is driven in the longitudinal direction of the developing part 3 with this signal, and the developer of the developer housing part 1 is supplied to only the lacking part. Thus, even when printing is carried out on a small-sized sheet, a void, the degradation of toner, contamination inside a machine, etc., are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a developing device for an image forming apparatus that employs an electrophotographic method.

[Prior Art] An example of an image forming apparatus employing a conventional electrophotographic method is the one shown in FIG.

In FIG. 6, 11 is a photosensitive tram as a latent image carrier, and around the photosensitive tram 11 is a pre-exposure lamp.
2. Secondary charger 13, developing device 14, pre-transfer exposure lamp 15, transfer charger 16, separation charger 17, cleaner 18
or is arranged. In addition, near the photosensitive drum 11,
A registration roller 19 and a fixing device 20 are provided.

First, the photosensitive tram 1 is charged with electricity removed by the pre-exposure lamp 12.
1 is uniformly charged by the -.order charger 13. Thereafter, a laser beam scanner (for example) is attached to the photosensitive drum 11.
(not shown), exposure is performed only according to the image signal,
An electrostatic latent image is formed on the photosensitive drum II. This electrostatic latent image is visualized as a toner image by the developing device 14 using toner as a developer. This toner image is slightly neutralized by a pre-transfer exposure lamp 15 and then transferred by a transfer charger 16 onto a transfer paper P which is conveyed toward a photosensitive drum 11 by a registration roller 19 at the same timing.

The transfer paper P on which the toner image has been transferred is separated from the photosensitive tram 11 by the separation charger 17 and then conveyed to the fixing device 2°, whereby the toner image is fixed and fixed on the transfer paper PL. Further, the photosensitive tram 11 after the transfer is cleaned of residual toner by a cleaner 18, and is prepared for the next image formation.

An example of a developing device used in the image forming apparatus as described above is shown in FIGS. 7 and 8. The developing device is composed of a hopper part 1, which is a developer storage section for storing toner, located at the rear upper part, and a developing section 3, which is located at the front lower part and has a developing sleeve 2 as a developer carrier. , near the boundary with the developing section 3 at the bottom of the hopper part 1 is a Macnet roller 4 serving as a developer conveying body that supplies toner to the developing section 3.
0 is set. Further, the toner is stirred in the hopper part 1 by rotating around a shaft 41.

A first agitation member 6 is provided which moves the toner towards the Macnet roller 40.

On the other hand, inside the developing section 3, the toner supplied from the hopper part 1 is stirred by rotating around the shaft 42, and the toner is uniformly distributed in the longitudinal direction of the developing sleep 2. A second agitation member 7 for moving the liquid toward the developing sleep 2 is also provided. Furthermore, a toner amount detection member 5 is disposed on the inner wall in one direction of the developing section 3 to detect the amount of toner within the developing section 3. The first stirring member 6 and the magnetic roller 40 are rotationally driven by a signal from the toner amount detection member 5 serving as the remaining amount detection means, and the hopper part 1 is rotated.
The configuration is such that toner is supplied from the toner to the unit 3.

[Problem to be solved by the invention] However, in the above conventional example, for example, the maximum paper passing width is 594 mm (equivalent to AI vertical feed), and the reference paper passing position is the longitudinal center of the developing sleeve. In the case,
When A2 size paper is fed vertically (paper passing width 420 lb) and printed continuously, the toner in the developing device is consumed only in the paper passing area, and a toner amount detection member is installed. Toner remains in the areas at both ends of the developing sleeve in the longitudinal direction, including the area where the toner is removed. Is a second agitation member disposed in the developing section of the developing device to uniformly distribute the toner in the longitudinal direction of the developing sleep, or if the above-mentioned printing is performed continuously? However, since the developing device is very long, the agitation capacity of the second agitation member cannot keep up with it. Therefore, even though there is almost no toner in the longitudinal center of the developing section, there is sufficient toner in the area where the toner amount detection member is disposed, and the toner amount detection member detects the presence of toner. '', and it is not possible to rotate the first stirring member and the Macnet roller in the hopper section. As a result, toner is not supplied to the developing section, resulting in image defects such as white spots.

Therefore, a method has been proposed in which the toner amount detection member is disposed not at the longitudinal end of the developing section but at the longitudinal center where toner is always consumed no matter what size paper is passed through. According to this method, each time there is a shortage of toner in the longitudinal center of the developing section, the first stirring member and the Macnet roller are rotated to supply toner to the developing section, thereby preventing image defects such as the white spots mentioned above. Occurrence can be prevented. However, toner is also supplied to both longitudinal ends of the developing section where toner is not consumed, and toner is forced into these sections, resulting in toner deterioration and toner leaking from the opening near the developing sleeve of the developing section. This may lead to problems such as contamination inside the aircraft due to balloons.

The present invention solves the above problems and prevents the occurrence of white spots, toner deterioration, internal contamination, etc. even when printing on small size paper using a long device that can use AI size paper. The purpose is to provide a developing device that does not require

[Means for Solving the Problems] According to the present invention, the above object is to provide a developing device divided into a front developing section and a rear developer storage section, wherein the developing section and the developer storage section are separated from each other. In the developing device, the developing device has an endlessly movable developer conveying body disposed between the developer storage unit and the developing unit, which conveys and supplies the developer in the developer storage unit to the developing unit, wherein the developer conveying body is divided into a plurality of parts in the axial direction. This is achieved by setting each of them to be driven independently or in conjunction with a signal from the developer remaining amount detection means.

[Function] According to the present invention as described above, when there is a partial shortage of developer in the longitudinal direction of the developing section, the remaining amount of developer detection means transmits a signal indicating the shortage of developer, and In response to the signal, only the developer conveying body corresponding to the insufficient portion is driven in the longitudinal direction of the developing section. Therefore, the developer in the developer storage section is supplied only to the insufficient portion.

[Example] The first to third embodiments of the present invention are illustrated in the first to third embodiments of the attached drawings.
This will be explained with reference to FIGS. Note that parts common to the conventional device shown in FIGS. 6 to 8 are denoted by the same reference numerals, and a description thereof will be omitted.

<First Embodiment> First, a first embodiment of the present invention will be described using FIG. 1 and FIG. 2.

Now, FIG. 1 shows the configuration of a developing device according to the present invention. In FIG. 1, reference numeral 1 denotes a part of a hopper which is a developer storage part, and a developing part 3 having a developing sleeve 2 which is a developer carrier is formed in front of the hopper part l. Macnet rollers 4 (4a, 4b, 4c) serving as developer conveying bodies are divided into five parts in the longitudinal direction between the hopper part 1 and the developing part 3.
A toner amount detection sensor 5 (5a), which is a means for detecting the remaining amount of developer, is provided near each magnetic roller.
.

5b, 5c) are provided. Further, a first stirring rod 6 is provided in the hopper part 1, and a second stirring bar 6 is provided in the developing section 3.
It is arranged so that it can rotate freely.

In this embodiment, the magnetic roller 4, which has a total length of 600 ounces and is used to supply toner from one part to the developing section 3, is divided into five parts in the longitudinal direction. Specifically, the positions are 148.5 mm each on the left and right, and 210 mm each on the left and right with respect to the longitudinal center line o-o' of the developing section.
It is divided into units of mm, and parts indicated by the same reference numerals in the figures are configured to rotate in conjunction with each other. Rotation is effected by a drive motor (not shown). Further, on the back side of the developing section 3, piezo elements serving as a toner amount detection sensor 5 are arranged at three positions shown in the figure.

Next, the outline of these operations will be explained using Fig. 2.
During a series of image forming processes, when the toner in the developing section 3 is consumed and reduced to a predetermined amount, and the piezo element 5a and the control circuit determine that there is no toner, the signal is sent to the Macnet roller 4a. drive motor 8a connected to
The toner is transmitted from the hopper part 1 to the developing section 3 by rotationally driving the Macnet roller 4a.

Here, toner supply is controlled by the piezo elements 5 (5a, 5b, 5c) and the control circuit as follows. However, the following control is an example and is not limited to this.

First, if the piezo element 5 continues to be in the "tonerless state" for two consecutive seconds after detecting the "tonerless state", it is recognized as the "first stage 1 toner-free state". The [
If the piezo element 5 detects the "toner present state" for 2 consecutive seconds within 7 seconds from the time when the "first stage no toner state" is recognized, the "toner present state" is recognized. but,
If the "toner present state" cannot be detected for 2 consecutive seconds or more during the above 7 seconds, it is recognized as the "second stage no toner state", and after 1 second, the first stirring member 6 and the Macnet roller 4 are rotated to remove the hopper. Toner is supplied from part 1 to developing part 3.

The maximum toner replenishment time in L is 10 seconds, and even during this time, if the ESO element 5 detects the "toner present state" for 2 consecutive seconds, the state returns to the "toner present state" and toner supply is immediately stopped. . However, in any case -H
Once toner replenishment is started, toner replenishment continues for at least 3 seconds. This is the first stirring member 6 and the Macnet roller 4.
This is to eliminate uneven supply of toner in these axial directions.

If the above toner replenishment control process is repeated twice, and the toner replenishment process is repeated twice with an interval of 10 seconds, it is determined that there is no toner in the hopper part 1, and the operator By lighting up a warning lamp (not shown), "
It notifies you that there is no toner and prompts you to replenish toner to a portion of the hopper.

According to the present embodiment, it is possible to supply toner from part 1 of the toner only to the portion of the developing section 3 where the toner has been consumed and decreased. For example, when printing is repeated using an A2 size paper that is fed vertically, the toner in the vicinity of the magnet rollers 4a and 4b corresponding to the paper passing area in the developing section 3 is gradually consumed. Then, when the piezo element 5a and the control circuit determine that there is no toner, the Macnet roller 4a is driven to rotate, and toner is supplied from the hopper part 1 to the developing section 3. Similarly,
When the piezo element 5b and the control circuit determine that there is no toner, the magnet roller 4b is rotated,
Toner is supplied from the hopper part 1 to the developing section 3. However, inside the developing section 3.

The toner near the Macnet roller 4C, which corresponds to the non-sheet passing area, is not consumed, and the piezo element 5c and the control circuit
Macnet roller 4c because it is determined that there is toner
is not driven, and toner is not supplied from the hopper portion 1 to the developing section 3.

As explained above, since toner is supplied only to areas where there is insufficient toner in the developing section 3, images such as white spots due to false detection of remaining toner when printing on small-sized paper, as described above, can occur. It is possible to prevent problems such as defects, toner deterioration due to further toner being forced into the developing section 3 where there is sufficient toner, and toner blowing out from the opening near the developing sleeve 2. Become.

It is also possible to further divide the magnetic roller so that it can handle A4 vertical feeding, or to use a toner amount detection means such as photodetection instead of the piezo element.

<Second Embodiment> Next, a second embodiment of the present invention will be explained using FIG. 3 and FIG. omitted.

In this embodiment, the Macnet roller 4 is divided into five sections as in the first embodiment, or the piezo element as the toner amount detection sensor 5 is disposed only in the center in the longitudinal direction of the developing section. This is different from one embodiment.

The outline of these operations will be explained using FIG. 4. During a series of image forming processes, the toner in the developing section 3 is consumed and the amount of toner decreases to a predetermined amount, and the piezo element 5 and the control circuit When it is determined that there is no toner, the magnetic roller 4 in the area corresponding to the paper size is detected based on the paper size signal inputted in advance to the control circuit by the paper size detection means (9 shown in the figure) provided in the main unit 5, e.g. In the case of A3 vertical feed, use only the Macnet roller 4a,
In the case of two vertical feeds, the Macnet rollers 4a and 4b are driven to rotate, and toner is supplied from the hopper part 1 to the developing section 3. Note that the paper size detection means may be any conventionally known means.

According to this embodiment, since only one piezo element is used, the cost is low, and since toner is supplied only to areas in the developing section where toner is insufficient, the above-mentioned white spots, toner deterioration, toner blow-out, etc. Is it possible to prevent this?

<Third Example> Next, a third embodiment of the present invention will be described using FIG. 5.

Note that the same reference numerals are given to the same parts as in the second embodiment, and the explanation thereof will be omitted.

In this embodiment, the Macnet roller 4 and the piezo element 5 have the same structure as shown in the second embodiment, or are formed from a linear member on the rotating shaft of the first stirring rod 6 in the hopper part 1. This embodiment differs from the second embodiment in that a large number of oval members 9 are provided which are obliquely inclined in a certain direction. This oval member 9 has the function of leveling the toner present in the hopper portion 1 approximately evenly across its longitudinal direction.

For example, when printing is repeated using A3 size paper in vertical feed, the toner near the magnet roller 4a corresponding to the paper passing area is gradually consumed in the developing section 3.
At some point, the Macnet roller 4a is rotated by signals from the piezo element 5 and the control circuit, and toner is supplied from the hopper member 1 to the developing section 3. After this toner supply is repeated several times, the state of the toner in the hopper portion 1 is reduced to 4, which is the amount of toner consumed by the magnetic roller 4.
This results in an uneven state in which there is almost no toner in the vicinity of a, and there is a sufficient amount in the vicinity of the Macnet rollers 4b and 4c, which correspond to non-sheet passing areas where no toner is consumed. In such a state, even though the amount of toner remaining in the hopper part l is large, the toner amount detection means will judge that there is no toner, and the hopper part l will It is not possible to make effective use of the toner present inside the printer.

However, in this embodiment, by disposing the oval member 9 as described above, it is possible to prevent the toner from being unevenly distributed in the hopper part l, and to make effective use of the toner. It is possible to extend the cycle of toner replenishment work to the part 1 and improve work efficiency.

[Effects of the Invention] As explained above, the present invention is characterized in that the developer conveying body is divided into a plurality of parts in the axial direction, and each part is driven independently or in conjunction with a signal from the remaining amount of developer detecting means. is set to . Therefore, it is possible to supply toner from a part of the hopper only to the areas in the developing section where there is a lack of toner, and even when printing on small-sized paper, it is possible to avoid white spots due to false detection by the toner amount detection means. It is possible to provide an image forming apparatus that can prevent image defects such as the above, toner deterioration due to toner pressure, and internal contamination due to toner blow-out, and that can obtain images with good and high quality.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a device according to a first embodiment of the present invention, FIG. 2 is a block diagram showing a control system in the device shown in FIG. 1, and FIG. 3 is a diagram of a device according to a second embodiment of the present invention. 4 is a block diagram showing the control system in the device shown in FIG. 3; FIG. 5 is a partially cutaway perspective view showing the schematic structure of the device according to the third embodiment of the present invention; FIG. 6 7 is a sectional view showing a schematic configuration of a conventional image forming apparatus, FIG. 7 is a sectional view showing a schematic configuration of a conventional developing device used in the apparatus shown in FIG. 6, and FIG.
The figure is a partially cutaway perspective view of the apparatus shown in FIG. ■・・・・Developer storage section (hopper) 3・・・・・
・Developing section 4...Developer transport body (magnetic roller) 5・
...Remaining developer amount detection means (toner amount detection member)

Claims (1)

[Scope of Claims] A developing device divided into a front developing section and a rear developer storage section, wherein the developing device is arranged between the developing section and the developer storage section, and the developing device in the developer storage section is arranged between the developing section and the developer storage section. In a developing device having an endlessly movable developer conveying body for conveying and supplying developer to the developing section, the developer conveying body is divided into a plurality of parts in the axial direction, and each of the developer conveying bodies is divided into a plurality of parts in the axial direction. A developing device characterized by being set to be driven independently or in conjunction with a signal.