JPH01154179A - Image forming device - Google Patents

Abstract

PURPOSE:To keep toner concentration precise and constant by writing the concentration of toner as a standard developer into a nonvolatile memory at the time of initiation, comparing a toner concentration which is detected when an image is formed with the standard toner concentration which is read out of the memory, and then replenishing the toner. CONSTITUTION:At the beginning, the toner concentration as a standard is detected by an inductance sensor 34. Said toner concentration is written into the nonvolatile memory 37. At the time of forming an image, the toner concen tration detected by the inductance sensor 34 is controlled so that it has the same concentration as the standard value. The toner concentration which is read out of the nonvolatile memory by a reading means is displayed on an displaying part 32. Thus, the toner concentration is kept precise and constant.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus such as an electronic copying machine, and more particularly to an image forming apparatus that can accurately control the toner concentration of a developer. .

(Background of the Invention) An electronic copying machine exposes a charged photoreceptor (hereinafter, a photoreceptor drum will be explained as an example) to light according to document information to form an electrostatic latent image, which is then converted into a visible image using toner. This device transfers and fixes this visible toner image onto transfer paper. In recent years, this type of electronic copying machine has been used in all fields of industry.

FIG. 5 is a configuration diagram showing an example of the configuration of this type of electronic copying machine. When the operator presses a copy button (not shown), the device shown begins copy wrestling. That is, the photosensitive drum 1 rotating in the direction of the arrow is moved to the cleaning section 2.
After the residual toner on the drum is removed by the blade, the surface of the drum is charged with an electric charge by the charging electrode 3.

Next, the charges on the photosensitive drum 1 are erased by the charge erasing section 4 . The charged area of the photosensitive drum 1 is exposed to light reflected by the original 6, and an electrostatic latent image is formed on the drum surface. That is, the original 6 is irradiated with light from the exposure unit 5, which is movable in the direction of the arrow shown in the figure, and the reflected light containing the original information reaches the photosensitive drum 1 via the mirrors M1 to M3 and the lens system L1. , the drum surface is exposed to light to form an electrostatic latent image on the drum surface. This electrostatic latent image is converted into a visible image by adsorption of toner in the developing section 7. Thereafter, the toner visible image on the drum surface is transferred to the transfer paper (
transferred to copy paper). After the transfer, the transfer paper is separated from the photosensitive drum 1 and transferred to the fixing roller 10 by the conveyance mechanism 9.
sent to. The transfer paper is then heated by the fixing roller 10, the toner is fused to the transfer paper, and the copying process is completed.

The exposure section 5 and the mirror M1. M2. ．． The part formed by +M with M3 (the part surrounded by a broken line) is the optical unit 20.
It can be moved in the direction of the arrow in the figure by a moving mechanism (not shown). Here, in order to always keep the optical path length constant, the first mirror M1 and the exposure section 5 are connected to the second mirror M1. Third mirror M2. It moves at twice the speed of M3. Here, since the light source 21 in the exposure device 5 is comprised of, for example, a bar-shaped fluorescent lamp or a halogen lamp perpendicular to the plane of the paper, the optical unit 20 can scan the entire surface of the original 6.

Incidentally, the developing device used in this type of electronic copying machine uses a two-component developer consisting of toner and carrier. The durability of this two-component developer deteriorates rapidly when the toner concentration falls below a certain value. For example, when the toner concentration is kept at 5% and when it is kept at 2%, the durability of the latter may be half that of the former. Therefore, it is necessary to control toner replenishment so that the toner visible image does not fall below a certain value.

2. Description of the Related Art To detect the toner concentration in a developing device using a two-component developer, there is a toner amount detection method using inductance. This utilizes the fact that the carrier contained in the developer is a magnetic material, and detects the toner concentration by placing an inductance sensor with a coil in the developer. Specifically, when the toner concentration changes, Focusing on the fact that the mixing ratio of toner and carrier changes and the magnetic permeability changes, the magnetic permeability of the developer is measured to determine the toner concentration.

Then, the output voltage of this inductance sensor and If lightning voltage are compared, and the output voltage of the inductance sensor is
Toner is replenished to be equal to the reference voltage, and as a result, the toner concentration is controlled to be constant.

(Problems to be Solved by the Invention) Incidentally, there are variations in the output of the above-mentioned inductance sensor, and it is necessary to adjust the output with a variable resistor or the like. In other words, so that the output voltage of the inductance sensor becomes a constant value when measuring toner of the standard density: J
I had to keep it in order.

However, such adjustments are not very accurate. Therefore, if the output voltage of the inductance sensor is not accurate, the toner concentration will always be controlled to be a different concentration.

Further, when the developing device is replaced, the output voltage of the sensor described above must be adjusted for each replaced vision device, which is very troublesome.

Another possible method is to store a reference value in memory and perform control based on this value. however,
There is also a risk that an abnormal value will be stored in the memory and control will be performed based on this value.

The present invention has been made in view of the above problems, and an object of the present invention is to realize an image forming apparatus that can easily maintain toner density accurately and always constant.

(Means for Solving the Problems) The present invention, which solves the above problems, includes an electrostatic latent image forming means for forming an electrostatic latent image on a photoreceptor, and a developer containing toner to form the electrostatic latent image. A developing means for making a visible image, a transferring means for transferring the image visually purified by the developing means onto a transfer paper, a fixing means for fixing the image transferred to the transfer paper, and a toner of the developer in the developing means. a toner concentration detection means disposed in the developing means for detecting the density; a nonvolatile memory; a writing means for storing the toner concentration of the reference developer into the nonvolatile memory; a toner concentration control means for controlling the toner concentration so that the toner concentration of the developer detected by the detection means is equal to the reference concentration; a reading means for reading out the toner concentration written in the nonvolatile memory; The present invention is characterized by comprising display means for displaying the toner density read out by the reading means.

(Function) First, the toner replenishment port serving as a reference is detected by the toner concentration detection means, and the detected toner concentration is written in the nonvolatile memory. During image formation, the toner density is controlled so that the toner density detected by the toner density detection means is equal to the reference value.

Further, the toner degree read out from the nonvolatile memory by the reading means is displayed on the display section.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the electrical pathogenesis of one embodiment of the present invention.

In the figure, 30 is a CP that controls each part of the image forming apparatus.
U, 31 is an operation input section for the operator to input various instructions; 32 is a display section for confirming the above inputs and for displaying messages from the CPU 30; 33 is provided in the current 9 device 7; , a toner remaining sensor that detects the remaining amount of toner, 34 an inductance sensor that measures the magnetic permeability of the developer and outputs a voltage according to the toner concentration, and 35 that is provided in the developing device 7 and that performs toner replenishment. The toner replenishing means 36 is an A/D converter that converts a voltage value corresponding to the toner concentration detected by the inductance sensor 34 into a digital value.
A D converter 37 is a non-volatile memory into which the toner density converted into a digital value by the A/D converter 36 is written in by an occupation instruction from the CPU 30 and read out by a read instruction; A D/A converter 39 converts the digital toner density data into an analog value, and a D/A converter 39 stores a voltage value corresponding to the toner density given from the inductance sensor 34 during image formation and a non-volatile memory 37. A comparator 40 compares the voltage value corresponding to the reference toner concentration and outputs a voltage corresponding to the difference between these two inputs, and a comparator 40 instructs the toner replenishing means 35 to replenish toner according to the output voltage of the comparator 39. This is a toner replenishment instruction means.

FIG. 2 is a sectional view showing the structure of the developing device 7 together with the photosensitive drum 1. As shown in FIG. In this figure, the same parts as in FIG. 1 are given the same numbers, and detailed explanations are omitted. 1 is a photosensitive drum, 7 is a developing device, 33 is a toner remaining amount sensor that detects the remaining toner m from vibrations when toner is replenished, 34 is an inductance sensor that detects the toner concentration in the developer, 35
35a and 35b are rollers driven when replenishing toner, and 35C are rollers 35a and 3.
5b is a driven belt; 35d is a carriage that is attached to the belt 35c and replenishes toner; 41 is a toner replenishing port; 42 is a toner replenishing means;
an auxiliary roller 43 that sends out the toner replenished by d;
44 is a main stirring section for stirring the developer consisting of toner and carrier; 44 is a sub-stirring section for stirring the developer; 45
Reference numeral 46 denotes a developing sleeve for attaching toner to the electrostatic latent image on the photosensitive drum to perform development, and 46 is a spike regulation plate for regulating the height of developer spikes on the sleeve 45.

First, the operation of the developing device 7 will be explained. The toner supplied from the toner supply port is transferred to the auxiliary row 542 by the gear ridge 35d of the toner supply means 35 when there is a toner supply instruction. At this time, the residual toner sensor 33 detects the remaining amount of toner due to the vibrations generated when the carriage 35d carries the toner. As the auxiliary roller 42 rotates, the toner is dropped downward. Then, the developing agent (toner and carrier) already in the current pump device and the toner are stirred by the main stirring section 43 and the sub-stirring section 44 . Here, the inductance sensor 34 detects the toner concentration by measuring the transmittance (a rate) of the developer. A spike of the developer is formed on the developing sleeve, and a spike regulating plate 46 is used to prevent the phenomenon The height of the spikes is regulated.The latent image on the photosensitive drum 1 is developed by the developer that has passed through this, and becomes a toner image.

Note that this developing bag @7 is configured to be easily attachable to and detachable from the main body of the copying machine. Each sensor (
The detection output of 1 is supplied to the CPU 30. For this reason, develop with toner of different colors! You can easily support color copying by changing the position. In addition, by connecting or opening any two terminals of the connector on the developing device side depending on the color of the toner, it is possible to distinguish from the copier main body which color developing device is installed. be able to.

The operation of this embodiment will be described below with reference to FIGS. 1 and 2.

First, at the initial stage or after replacing the replaceable developing device, the following initial setting operation is performed.

When an initial setting instruction is received from the operation input section 31, the CPU 3
0 is currently 1g! Main stirring section 43 and sub-stirring section 4 of equipment f17
4, instruct the developer to be stirred for a certain period of time (for example, 90 seconds until the toner and carrier in the developer are well mixed). At the initial stage, a developer of standard concentration (for example, toner vi
4%) is injected into the developing device. After stirring,
The voltage corresponding to the toner density of the developer having the reference density measured by the inductance sensor 34 is converted into a digital value by the A/D converter 36 and written into the non-volatile memory 37 according to an instruction from the CPLI 30 . When writing to the nonvolatile memory 37 is completed, the initial setting operation ends.

Furthermore, as shown in Fig. 3, even if the sensors are of the same type, A
, B, and C, and the output voltages (VA, Vs, Vc) for the same concentration are different. Therefore, the values written in the nonvolatile memory 37 differ slightly depending on the sensor used.

In some cases, different color toners are stored in a plurality of replaceable developing devices, and the developing devices are used depending on the usage situation. Even in such cases, black is the most frequently used color.

In the case of toner other than black toner, the latitude with respect to toner density is wide, and a certain amount of deviation in toner density can be tolerated. Therefore, the nonvolatile memory 37 stores the black toner base tI! It is sufficient to write only a degree of data.

FIG. 4 is a configuration diagram showing an example of a configuration for determining the type of a removable developer bag. A connector 50 is provided on the developing device 7 side, and a connector 51 is provided on the copying machine main body side. When the developing device 7 is attached to the copying machine main body, the terminals 50a, 50b, 50c of the connector 50,
50d and the terminals 51a, 51b, 51c of the connector 51,
51d are connected to each other.

In such a connector, for example, in the case of a phenomenon device containing black toner, terminals 50c and 50d are short-circuited, and in the case of a phenomenon device containing toner other than black, terminals 50c and 50d are shorted.
Leave c and 50d open.

The terminals 51c and 51d are connected to the CPU 30, and the CPU 30 monitors both terminals, thereby making it possible to determine the type of developing device.

Next, toner density control operation during image formation (copying) will be explained.

When a copying instruction is given from the operation input section 31, the CPU
30 gives a copy instruction signal to each section. As a result, a latent image is formed by charging the photosensitive drum and exposing it to light.

Development that attracts toner to this latent image, transfer to transfer paper,
Processing such as fixing (copy process) is then performed. At this time, the toner in the phenomenon agent has been consumed, and the toner Q degree is gradually decreasing.

Therefore, it becomes necessary to replenish the developer with toner.

Here, the detection output of the inductance sensor 34 is applied to one input terminal of the three comparators.

Further, the detection voltage of the sensor at the reference toker concentration written in the nonvolatile memory 37 is read out according to an instruction from the CPU 30 and is applied to the other input terminal of the comparator 39. The three comparators compare the voltages applied to both input terminals and output a voltage according to the difference between the two. Based on the output of the comparator 39, the toner replenishment instructing means 40 gives an instruction to the toner replenishing means 35 in the developing device 7 as to whether or not toner replenishment is to be performed. The toner replenishing means 35 replenishes toner to the current frame material based on the above instructions.

As a result, the toner concentration in the developer increases, and toner replenishment is performed until the toner concentration matches the reference value.

As described above, toner replenishment is automatically performed based on the value written in the non-volatile memory, but there may be cases where it is desired to check the value written in the non-volatile memory. In such a case, the following operations are performed.

When there is an instruction from the operation input unit 31 to read a value written in the nonvolatile memory 37, the CPU 30 gives a read control signal to the nonvolatile memory 37.

As a result, the value read from the nonvolatile memory 37 (reference toner density 1!ll[) is converted into a display signal by the CPU 30 and displayed on the display section. Although this display may display the reference toner density as it is, the configuration can be simplified by converting it to an appropriate value and then displaying it in the area where the number of copies is displayed. As a result, it is possible to check whether the toner density written in the nonvolatile memory at the time of initial setting is a normal value. If this value is not within the normal range, you can perform the initial settings again.

As described above, toner replenishment is performed by writing the toner a degree of the reference phenomenon agent into the non-volatile memory at the time of initial setting, and comparing the toner concentration at the time of image formation with the reference toner density read from the non-volatile memory. This allows the toner density to be kept accurately and always constant. Furthermore, by displaying the reference toner density written in the nonvolatile memory on the display section, it is possible to easily confirm whether this reference value is normal.

(Effects of the Invention) As described above in detail, according to the present invention, the toner concentration of the reference developer is written in the nonvolatile memory at the time of initial setting, and the toner concentration at the time of image formation and the reference toner read out from the memory are Since toner replenishment is performed by comparing the toner density with the toner density, it is possible to realize an image forming apparatus that can accurately and always keep the toner density constant.

Further, by displaying the value written in the nonvolatile memory on the display section, the reference toner concentration can be easily confirmed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a sectional view showing the configuration of the developing device, FIG. 3 is a characteristic diagram of the inductance sensor, FIG. 4 is a configuration diagram of the connector, and FIG. FIG. 5 is a block diagram of a conventional electronic copying machine. 1... Photosensitive drum 7... Developing device 30...
・CPU 31...operation input section 32...
Display section 33... Toner remaining amount sensor 34... Inductance sensor 35... Toner supply means 36... Δ/D converter 3
7... Nonvolatile memory 38... D/A converter 39
... Comparator 40 ... Toner replenishment instruction means 41 ... Toner replenishment port 42 ... Auxiliary roller 43
...Main stirring section 44...Sub-stirring section 45...
Developing sleeve 46...Standing regulation plate 50.51.
...Connectors 50a to 50d, 51a to 51d...Terminal patent applicant: 2 Ka Co., Ltd.
Courtesy Ceremony Patent Attorney I
Shima Fuji 1 name square note 4 Fig. 1 Coral statue M

Claims (1)

[Claims] an electrostatic latent image forming means for forming an electrostatic latent image on a photoreceptor;
A developing device that visualizes the electrostatic latent image using a developer containing toner, a transfer device that transfers the image visualized by the developing device onto a transfer paper, and a fixing device that fixes the image transferred to the transfer paper. a toner concentration detection means disposed in the developing means for detecting the toner concentration of the developer in the developing means; a nonvolatile memory; and a toner concentration of the developer serving as a reference is written in the nonvolatile memory. a toner concentration control means for controlling the toner concentration so that the toner concentration of the developer detected by the toner concentration detection means during image formation is equal to the reference concentration; 1. An image forming apparatus comprising: reading means for reading out the toner density read by the reading means; and display means for displaying the toner density read by the reading means.