JP2001147579A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device where correction of developer residue quantity detection is carried out automatically with a simple constitution. SOLUTION: In the device, adjustment anywhere on a field is possible by measuring corrected electrostatic capacity 120 between a development sleeve and a planar antenna 116 and calculating the residue toner quantity of a developer cartridge 115 by changing over an anlog switch SW to a side with a greater resistance value and repeatedly adjusting until the level of output is brought to a specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a developer (toner)
More particularly, the present invention relates to an image forming apparatus that forms an image on a sheet (recording paper), and particularly relates to a method of measuring a capacitance between an antenna electrode and a developer carrying member (developing sleeve) via toner to obtain a remaining amount of toner. When measuring between machines,
The present invention relates to correcting differences in stray capacitance and sensitivity due to a cartridge or the like.

[0002]

2. Description of the Related Art Generally, there is a color image forming apparatus having a rotating developing cartridge. This type of color image forming apparatus repeats a process of transferring a toner image formed by charging, exposing, and developing on a photosensitive drum onto an intermediate transfer belt a plurality of times, and finally, a plurality of colors on a recording paper sheet. Is used to obtain a color image by re-transferring the superimposed image.

[0003] A conventional technique will be described below with reference to the drawings. FIG. 4 is a longitudinal sectional view of the color image forming apparatus. As shown in the figure, the photosensitive drum 100, a charging roller, and a cleaner box 113 for accumulating waste toner are integrally formed as a cartridge in the entire apparatus. A photosensitive drum cartridge which is replaced when the specified number is reached and which is detachable from the main body is provided.

Further, on the left side of the photosensitive drum cartridge, a toner as a developer and a toner accommodating portion and a developing portion for developing are integrally formed into a cartridge, and the consumption of the accommodated toner as the accommodated developer is completed. Cartridges 115Dm, Dy, Dc, and Dk as a plurality of developing means detachable from the apparatus main body and replaced by
(Generically referred to as a developing cartridge 115).

The developing cartridge 115 is rotatably supported by the developing rotary unit 110, and is rotated about a rotation shaft 111 to rotate the developing cartridge 1 on the same cylinder.
Fifteen development options are set. That is, the developing rotary unit 110 is provided with each developing cartridge 1 for each color development.
15 is moved to a position opposing the photosensitive drum 100 to drive the photosensitive drum 100 for development.

On the right side of the photosensitive drum cartridge, an intermediate transfer belt (hereinafter referred to as ITB) 103 having a function of transferring an image on the photosensitive drum 100 onto the belt for each color toner is disposed.

The photosensitive drum 100 having the above configuration is
It is driven in a direction indicated by an arrow at a peripheral speed of 103 mm / sec by a driving unit (not shown).

The photosensitive drum 100 is formed by coating a photoconductor made of an organic photosensitive member (OPC) on an outer peripheral surface of an aluminum cylinder having a diameter of 40 mm.
-Si, CdS, Se or the like may be used.

An exposure device 107 including a laser diode, a polygon mirror driven by a high-speed motor, a lens, a folding mirror, and the like is disposed above the apparatus main body.

Next, the operation of the apparatus will be described. On the charging roller in contact with the photosensitive drum 100, an AC voltage of Vp-p (peak-to-peak) of -1500V at an AC frequency of 700Hz is superimposed on a DC voltage of -700V, and the photosensitive drum 100 is uniformly charged to approximately -700V. Is done.

On the other hand, when a signal according to magenta image information is input to the laser diode, the photosensitive drum 100 is irradiated with laser light through an optical path. By the irradiation of the laser light, the photosensitive drum 100 charged by the charging roller has a position irradiated with the laser light substantially −100.
V and an electrostatic latent image is formed.

When the photosensitive drum 100 further moves in the direction of the arrow, the electrostatic latent image on the photosensitive drum 100 is visualized by one developing cartridge 115Dm disposed at a predetermined position, and a toner image is formed.

The photosensitive drum 100 further moves in the direction of the arrow, and the toner image on the photosensitive drum 100 is transferred onto the ITB 103 by a high-voltage power supply (not shown) by a voltage between the photosensitive drum 100 and the ITB 103.

The above process is repeated for each of the developing cartridges 115Dy, Dc, and Dk for cyan, yellow, and black.
By performing the same processing by visualizing the electrostatic latent image by the above, a toner image of a plurality of colors, that is, a color image, is formed on the ITB 103.

The ITB 103 on which a color image has been formed is
The image is retransferred to a recording sheet conveyed at the final time.

The recording paper is conveyed to a fixing device 104 for fixing by heating and pressing, and the unfixed color image transferred onto the recording paper becomes a color image fused and fixed by the fixing device 104.

Here, the ITB 103 is not transferred to the recording paper.
The toner remaining on the upper surface is cleaned by a cleaning device 112 such as a fur brush or blade means.

The recording paper on which a color image is formed is fed from a cassette 101 or a multi-tray, and
At 06, the color image is transferred from the ITB 103, guided to the fixing device 104 by the transport belt 105, and fixed, and then discharged to the face-up tray (image upward) 108 or the face-down tray (image downward) 1
09 is discharged.

The developing cartridge 115 used here
Has a developing sleeve as a developer carrier for developing the toner into a latent image on the photosensitive drum 100, and has an antenna on the bottom surface of the cartridge exterior facing the developing sleeve with the toner interposed therebetween. A planar antenna 116 is provided as an electrode (see FIG. 5).

The developing sleeve and the planar antenna 116 form a capacitor, and the capacitance changes depending on the amount of toner existing between the two. Therefore, the remaining amount of toner in the cartridge is detected by measuring the capacitance 120 between the developing sleeve and the planar antenna 116 via the toner.

FIG. 5 shows a conventional toner successive approximation residual detection circuit. Inside the developing cartridge 115, there is a developing sleeve, which is configured to uniformly carry the toner.

When the developing high voltage 118 is applied and the developing sleeve is driven to rotate, toner flies from the developing sleeve onto the electrostatic latent image formed on the photosensitive drum 100 facing the developing sleeve, and the electrostatic latent image is formed. Developed.

The successive comparison is performed by measuring the electrostatic capacity 120 between the developing sleeve and the planar antenna 116 with the AC component of the developing high voltage when the developing cartridge 115 is opposed to the photosensitive drum 100 and developed.

Here, reference numeral 119 denotes a capacitor, which is equivalent to a capacitance 120 coupled between the developing sleeve and the planar antenna 116 when there is no toner remaining in the cartridge.

Reference numeral 123 denotes a rectifier circuit B, which rectifies an AC component obtained by AC coupling the developing high voltage with a capacitor 119. 1
Reference numeral 29 denotes a volume resistor VR, which changes the relative ratio between the current flowing to r130 and the current flowing to R131.

Then, the current flowing to R131 is adjusted so as to be converted into a DC voltage by the integrating circuit B124.

On the other hand, the rectifying circuit A and the integrating circuit A connected to the planar antenna 116 are composed of a rectifying circuit B and an integrating circuit B.
And the output from the rectifier circuit A is output to the integration circuit A without being adjusted by a resistor.

Reference numeral 125 denotes an amplifying circuit.
The voltage output by B is compared, and the voltage corresponding to the remaining amount of toner in the developing cartridge 115 is amplified.

An analog signal output from the amplifier circuit 125 is input to an AD port of the CPU 126 and is AD-converted into digital data as an output value. A memory circuit 127 stores a data table of the remaining amount of toner corresponding to the output data AD-converted by the CPU 126.

The CPU 126 determines, based on the output data output from the amplifier circuit 125 and the remaining toner data from the memory circuit 127, how much toner remains in the developing cartridge 115 or how much the developing cartridge 115 has. The replacement time is measured and determined, and the determination is notified to the outside by the display circuit 128.

FIG. 6 is a graph showing the remaining amount of toner and the output of the amplification circuit 125. The relationship when the capacitance between the apparent developing sleeve and the planar antenna 116 fluctuates due to the individual difference of the developing cartridge 115 and the stray capacitance on the wiring.

This variation is corrected by adjusting the volume resistance VR1.
29 was adjusted according to the adjustment target, and the shift amount of the characteristic was adjusted.

The adjustment by the volume resistor VR129 is carried out by mounting a standard developing cartridge full of toner after all assembly is completed in the manufacturing process of the apparatus.
The assembler has made adjustments so that the converted data has a specified value.

[0034]

However, providing a planar antenna 116 for each developing cartridge 115 is costly. Further, since the size of the developing cartridge 115 provided with the planar antenna 116 becomes large, there is a demerit that the size of the image forming apparatus must be increased.

As described above, the adjustment of the stray capacitance coupled on the wiring path of the successive approximation residual detection circuit, the capacitance 120 and the sensitivity between the developing sleeve and the planar antenna 116 that differ depending on the body and the developing cartridge 115 are performed. Therefore, it is necessary to adjust the volume resistor VR 129 on the circuit so that the detection output becomes a specified value after the standard developing cartridge is attached in a state where all the devices are incorporated. It was accompanied by work.

After manufacturing, a serviceman or the like performs calibration of the successive approximation residual detection circuit in a field,
It was impossible to correct the error in the toner remaining amount detection.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image forming apparatus which automatically corrects the detection of the remaining amount of developer with a simple configuration. It is in.

[0038]

In order to achieve the above object, according to the present invention, a developer carrying member for carrying a developer and a developer to be carried on the developer carrying member are housed. A developing means for applying a high developing pressure to the developer carrying member to perform development, wherein the developer in the storing means is provided at a position where the developing means performs development. An antenna electrode disposed opposite to the developer carrying member with the interposition therebetween, and an output value based on a capacitance between the developer carrying member and the antenna electrode due to a developing high voltage applied to the developer carrying member When the developer is fully filled in the storage means, the output value when the measurement means is fully filled is substantially equal to a predetermined value stored in advance. Adjustment for adjusting and controlling the measuring means for correction It includes a stage, the at the measuring means is corrected by said adjustment means, and calculates the developer remaining amount in said storage means.

In order to form a color image, it is preferable that the image forming apparatus includes a plurality of developing units for each color, and that the adjusting unit performs correction by controlling and adjusting the developing units for each color. .

When any one of the developing means for each color moves to a position for developing, one of the developing means in the storage means is sandwiched between one of the fixedly disposed antenna electrodes and the developer in the accommodating means. It is preferable that the developer carrier of the means is opposed.

[0041]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) A first embodiment will be described with reference to FIGS. First, a successive approximation residual detection circuit for detecting the remaining amount of toner in the developing cartridge based on the electric block diagram of FIG. 1 will be described. In addition,
Since the entire image forming apparatus is the same as the related art, the description is omitted here.

In FIG. 1, the planar antenna 116 is arranged on the central axis of the developing rotary unit 110 and is fixedly arranged so as to be always at a fixed position. Therefore, the size of the apparatus is reduced and the cost is reduced.

The memory circuit 127 is provided with a data table of the remaining amount of toner corresponding to the digital data as the output value which has been subjected to the A / D conversion in the same manner as in the prior art. The time switch information is also stored.

132, 133, 134 and 135 are analog switches SWa, SWb, SWc and SWd (collectively,
SW), and each analog switch is turned on / off independently by digital signals a, b, c, d from the CPU 126.

Reference numerals 136, 137, 138, and 139 denote resistors ra, rb, rc, and rd (collectively, r), and the respective resistance values satisfy ra <rb <rc <rd.

For example, when the analog switch SWa132 is turned on by the signal a, the ratio of the values of the currents flowing through R131 and ra136 is ra: R.

At this time, the capacitance coupled to the developing cartridge 115 and the wiring is added, and becomes larger than the value of the capacitance 120 between the developing sleeve to be actually detected and the planar antenna 116, and the output value output to the CPU 126 May be larger than a reference voltage (not shown) as a predetermined value of the AD converter.

Therefore, the CPU 126 turns off the analog switch SWa132, drives the digital signal b, and turns on the analog switch SWb133. Then R
The ratio of the value of the current flowing through 131 and rb137 is rb: R, the current flowing through R131 increases, and the output data decreases.

Hereinafter, when the analog switch SW is switched to turn on the analog switches SWc134 and SWd135, the output data can be further reduced.

Next, based on the flowchart of FIG.
An operation of adjusting and correcting the successive approximation residual detection circuit in the embodiment will be described.

At S1, it is confirmed whether or not the main body is set to the adjustment mode of the successive approximation residual detection circuit in the manufacturing process and the service maintenance.

In step S2, when the worker or serviceman mounts a standard developing cartridge full of toner or an equivalent reference developing cartridge for adjustment and inputs a command to start adjustment, the CPU sets the standard developing cartridge for adjustment. Is moved to a position facing the photosensitive drum 100. After stopping at a predetermined position, the developing high pressure 11
8 is applied (S3).

If the output data input to the CPU 126 is equal to or higher than the specified level in S4, the analog switch SW is switched to the one having the larger resistance value, and the adjustment is repeated until the output data level reaches the specified value (S5).

When the output data level reaches the specified value,
The analog switch SW information at that time is stored in the memory circuit 12.
7 (S6).

Thereafter, when the power supply of the device in the steady mode is turned on,
Based on the analog switch SW information stored in the memory circuit 127, the capacitance between the developing sleeve and the planar antenna 116 is corrected to a correct value, and the remaining amount of toner in the developing cartridge 115 is measured.

As described above, it is possible to easily adjust the capacitance and sensitivity between the developing sleeve and the planar antenna 116, which are different depending on the stray capacitance, the body, the developing cartridge, and the like coupled on the wiring path. However, the adjustment can be performed, and the remaining toner amount of the developing cartridge 115 can be accurately measured thereafter.

Further, since a single planar antenna 116 is arranged on the central axis of the developing rotary unit 110, the size of the apparatus can be reduced, and the cost can be reduced.

(Second Embodiment) FIG. 3 shows a second embodiment. In the first embodiment,
Although the adjustment is performed for the single-color developing cartridge, in the present embodiment, since each color or characteristic is different, the adjustment is performed for the color toner and the black toner having different high-voltage AC frequency capacities.

The other configuration and operation are the same as those of the first embodiment, so that the same components are denoted by the same reference characters and description thereof is omitted.

Hereinafter, based on the flowchart of FIG.
An operation of adjusting and correcting the successive approximation residual detection circuit in the embodiment will be described.

Steps S1 to S6 are the same processing as in the first embodiment. When the adjustment for the magenta developing cartridge 115Dm is completed in S7, the adjustment for the cyan developing cartridge 115Dc is performed from S2 to S6 in S8. Thereafter, similarly, the yellow developing cartridge 115Dy is adjusted in S9, and the black developing cartridge 115Dk is adjusted in S10, and the process ends.

With the above-described configuration, not only the same effects as in the first embodiment can be obtained, but also the adjustment of the color toner and the black toner in which the individual differences and the characteristics and the toner amounts differ depending on the developing cartridge. Can be applied to each of them, and it becomes possible to absorb variations and extend the measurement range.

In the present embodiment, the color order of the developing cartridge 115 to be adjusted is determined and adjusted. However, after the operator mounts the standard cartridge of each color in advance, any of the slots has a predetermined color. If the configuration is such that the cartridge can be identified, the CPU may automatically recognize and process the cartridge in any order.

In a developing cartridge for a color toner having substantially the same characteristics, if the adjustment values of two of the three colors are the same, the adjustment information for the third color is set to the same value as the other two colors. The black toner developing cartridge may be adjusted without performing the adjusting step.

[0066]

As described above, according to the present invention, the adjustment for correcting the electrostatic capacitance between the developer carrying member and the antenna electrode which is different depending on the stray capacitance, the body, the developing means, and the like coupled on the wiring path. The adjustment can be easily performed not only at the factory but also on the field, and the remaining amount of the developer can be accurately measured thereafter.

Further, by adjusting and controlling the developing means of each color, and correcting the electrostatic capacity between the developer carrying member and the antenna electrode, individual differences, characteristics, and amounts of the developing agents differing depending on the developing means. Adjustments can be made for each agent, and it becomes possible to absorb variations and extend the measurement range.

[Brief description of the drawings]

FIG. 1 is an electric block diagram illustrating an image forming apparatus according to a first embodiment.

FIG. 2 is a flowchart illustrating the operation of the first embodiment.

FIG. 3 is a flowchart illustrating the operation of the second embodiment.

FIG. 4 is a cross-sectional view illustrating a conventional image forming apparatus.

FIG. 5 is an electrical block diagram illustrating a conventional image forming apparatus.

FIG. 6 is a graph illustrating a relationship between a sensor output and a remaining amount of toner.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 photosensitive drum 110 developing rotary unit 115 developing cartridge 116 planar antenna 118 developing high voltage 119 capacitor 120 capacitance 121 rectifying circuit A 122 integrating circuit A 123 rectifying circuit B 124 integrating circuit B 125 amplifying circuit 126 CPU 127 memory circuit

Claims (3)

[Claims] An image forming apparatus comprising: a developer carrying member for carrying a developer; and a storage means for accommodating a developer to be carried on the developer carrying member, wherein a developing high voltage is applied to the developer carrying member. An image forming apparatus including a developing unit that performs development by performing, at a position where the developing unit performs development, an antenna electrode that is arranged to face the developer carrier with the developer in the storage unit interposed therebetween. A measuring means for measuring an output value based on a capacitance between the developer carrying member and the antenna electrode by a developing high voltage applied to the developer carrying member; and a developer fully filled in the storage means. And adjusting means for adjusting and controlling the measuring means so that the output value at the time of full filling measured by the measuring means is substantially equal to a predetermined value stored in advance. With the measuring means corrected by the adjusting means An image forming apparatus for calculating a remaining amount of the developer in the storage unit. 2. An image forming apparatus comprising a plurality of developing means for each color for forming a color image, wherein the adjusting means performs adjustment control for each of the developing means for each color to perform correction. The image forming apparatus according to claim 1, wherein: 3. When any one of the developing means of each color moves to a position where development is performed, one of the fixedly disposed antenna electrodes and the developer in the storage means are sandwiched between the one of the developing means and the one of the developing means. The image forming apparatus according to claim 2, wherein the developer carrier of the developing unit faces the developer carrier.