JPH01154172A - Image forming device - Google Patents

Abstract

PURPOSE:To keep toner concentration precise for every developing device by comparing the toner concentration of a developer at the time of image formation and the reference toner concentration read out of a memory according to the type of loaded developing device and controlling the toner concentration. CONSTITUTION:The developing device 7 is constituted attachably and detachably to/from the main body of an image forming device. First, the reference toner concentration is detected by a toner concentration sensor (inductance sensor) 34 and this detected value is written in the prescribed region of a nonvolatile memory 37 every color of the toner of the developing device 7. Then, at the time of the image formation, the toner concentration detected by the toner concentration sensor 34 is controlled so as to equalize the reference toner concentration for every color of the toner of the developing device 7. Thus, the toner concentration can be exactly kept at appropriate concentration in every developing device 7 even when it is replaced.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an image forming apparatus such as an electronic copying machine, and more specifically, when a plurality of replaceable developing devices are installed, each developing device The present invention relates to an image forming apparatus that can accurately control the toner S level of the apparatus.

(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 the copying process. 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. Then, the transfer paper is heated by the fixing roller 10, and toner Ej/1 is deposited on the transfer paper, and the copying process is completed.

The exposure section 5 and the mirror M1. M2. The portion formed by M3 (the portion surrounded by a broken line) constitutes the optical unit 20, and is movable in the direction of the arrow in the figure by a moving mechanism (not shown). Here, the first mirror M
1 and the exposure section 5 are connected to each other in order to keep the optical path length constant.
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.

By the way, 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 81 degrees 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 concentration does not fall below a certain value.

There is a toner (2) detection method using inductance as a method for detecting 81 degrees of toner in a developing device using a two-component developer. 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, Noting that the mixing ratio of toner and carrier changes and the magnetic permeability fluctuates,
The toner concentration is determined by measuring the magnetic permeability of the developer.

Then, the output voltage of the inductance sensor is compared with a reference voltage, and toner is replenished so that the output voltage of the inductance sensor becomes 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, it was necessary to adjust the output voltage of the inductance sensor to a constant value when measuring toner having a reference density.

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.

Furthermore, when replacing the current 1gl5A device, the output voltage of the sensor described above must be adjusted for each replaced developing device, which is very troublesome.

The present invention has been made in view of the above-mentioned problems, and its purpose is to maintain the toner density of each developing device at an accurate appropriate density even when replacing the developing device. The object of the present invention is to realize an image forming apparatus d that can perform the following functions.

(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 an electrostatic latent image. A developing means for visualizing the image; a transferring means for transferring the visualized image by the developing means onto a transfer paper; a fixing means for fixing the transferred image; a color information display means for outputting information corresponding to the color; a toner concentration detection means disposed in the developing means for detecting 81 degrees of toner in the developer in the developing means;
a non-volatile memory having a plurality of areas; a writing unit for writing the reference toner concentration of the developer into a predetermined area of the non-volatile memory according to the output of the color information display unit; and a write unit for displaying the color information during image formation. A readout means reads out a reference toner concentration of the developer from a non-volatile memory in accordance with the output of the means, and a toner concentration of the developer detected by the toner concentration detection means during image formation becomes equal to the reference toner concentration. The image forming apparatus is equipped with a toner density control means for controlling toner density and forms an image, and is characterized in that the developing means is configured to be detachable from the main body of the image forming apparatus. It is something to do.

(Function) First, a toner concentration serving as a reference is detected by a toner flow sensor, and the detected value is written in a predetermined area of a nonvolatile memory for each toner color of the developing device. During image formation, the toner density sensor detects 111 degrees of toner.
The toner density is controlled to be equal to the reference toner density for each color of toner in the developing device.

(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 configuration of an embodiment of the present invention.

In the figure, 7 is a developing device into which a developer containing toner of any color is injected. This developing device is detachable from the main body of the image forming apparatus. Reference numeral 30 indicates a CPU 131 that controls each part of the image forming apparatus. Reference numeral 32 indicates an operation input unit for inputting various instructions by the operator. Reference numeral 32 indicates a display unit for confirming the above-mentioned inputs and for displaying messages from the CPU 30. A toner residual sensor installed in the developing device 7 detects the remaining amount of toner; 34 is an inductance sensor that measures the magnetic permeability of the developer and outputs a voltage according to the toner concentration; 35 is the developing device [7]; 36 is an A/D converter that converts a voltage value corresponding to the toner 11 degrees detected by the inductance sensor 34 into a digital value;
A non-volatile memory 7 has a plurality of storage areas, in which the toner density converted into a digital value by the A/D converter 36 is written in by a write instruction from the CPU 30 and read out by a read instruction; 38 is a non-volatile memory 37; A D/A converter 39 converts the digital value of toner 81 degrees read out from the toner 81 degree data into an analog value, and 39 is the toner 111 provided from the inductance sensor 34 during image formation.
40 is a comparator that compares a voltage value corresponding to the toner concentration with a voltage value corresponding to the reference toner concentration stored in the nonvolatile memory 37, and outputs a voltage according to the difference between these two inputs. This is a toner replenishment instructing means for giving an instruction to replenish toner to the toner replenishing means 35 according to the output voltage of the toner replenishing means 39.

FIG. 2 is a sectional view showing the structure of the developing device @7 together with the photosensitive drum 1. 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 amount of toner from vibrations during toner replenishment; 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.
A belt driven by 5b, 35d a carriage that is attached to the belt 35G and replenishes toner, 41 a toner replenishment port, and 42 a carriage 35d serving as a toner replenishment means.
an auxiliary roller for sending out the tonneau replenished by 43;
44 is a main stirring section for stirring the developer consisting of toner and carrier; 45 is a sub-stirring section for stirring the same; 45
Reference numeral 46 denotes a developing sleeve for attaching toner to the electrostatic image on the photosensitive drum to perform development, and 46 is a spike regulating plate for regulating the height of the 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 f)st is transferred to the auxiliary roller 42 by the key X ridge 35d of the toner supply means 35 when there is a toner supply instruction. At this time, the remaining toner amount sensor 33 detects the remaining amount of l-ner due to vibrations generated when the carriage 35d carries toner. As the auxiliary roller 42 rotates, the toner is dropped downward. Then, the developer (toner and carrier) already in the developing device and the above-mentioned torch are stirred by the main stirring section 43 and the sub-stirring section 44 . Here, the inductance sensor 34 measures the magnetic permeability of this developer to detect the degree t-a. A spike of developing agent is formed on the developing sleeve J3, and the height of the spike of developer is regulated by a spike regulating plate 46. The electrostatic latent image on the photosensitive drum 1 is developed by the developer that has passed through this, and becomes a toner image.

Incidentally, this developing device 7 can be easily attached to and detached from the main body of the copying machine. Then, the detection output of each sensor is supplied to CI) jJ 30 via a connector that becomes connected when the developing device is attached to the copying machine main body.

Therefore, by replacing the developing device with a developing device containing toner of a different color, it is possible to easily handle color copying.

In addition, by displaying information according to the color of toner on any terminal of the connector on the Kawaden device side, it is possible to distinguish from the copier main body which color of toner the developing device is installed in. It is configured so that it can be done.

FIG. 3 is a configuration diagram showing an example of a configuration for determining the type of a detachable developing device. 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 installed in the copying machine main body, terminals 50a, 50b, 50c of the connector 50,
50d and terminals 51a, 51b, 51c of the connector 51
, 51d are connected to each other.

In such a connector, the color information display means 52 fixes each of the terminals 50c and 50d to a high level or low level voltage depending on the color of toner in the developing device. 10.1
It can represent four states such as 1. And terminal 5
By connecting 1C and 51d to the CPU 30 and monitoring both terminals, it is possible to determine the color type of the developing device.

Note that by increasing the number of terminals set in this way, it is also possible to discriminate even more types.

Furthermore, by connecting or opening a plurality of arbitrary terminals, it is possible to similarly discriminate each color.

The operation of this embodiment will be described below with reference to FIGS. 1 to 3.

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

When an instruction for initial till setting is received from the operation input section 31,
The CPU 30 is the main Ij! of the developing device 7! The agitation unit 43 and the sub-agitation unit 44 are instructed to stir the developer for a certain period of time (for example, 90 seconds until the toner and gear in the developer are well mixed). Initially, the developer is set to a standard density for each color (for example, if the developer is a black toner, the toner density is 4).
%) is injected into the developing device. At the end of stirring, the voltage corresponding to the toner density of the developer with the ill density measured by the inductance sensor 34 is converted into a digital value by the A/D converter 36, and is stored in the non-volatile memory 37 for each color according to instructions from the CPU 30. is written to the storage area according to the That is, the CPU 30 provides the non-volatile memory 37 with an occupation control signal and an address signal for specifying the storage fn area corresponding to the color of toner in the developing device. When this writing is completed, the initial setting operation ends. Note that this initial setting operation is performed for each developing device into which developer of a different color is injected.

Furthermore, as shown in Fig. 4, even if the sensors are of the same type,
They have different characteristics like A, B, and C, and have different output voltages (VA, VB, VC) for the same concentration.

Therefore, the value written into the non-volatile memory 37 is
It differs slightly depending on the sensor used. Furthermore, since the reference toner 81 degrees is different between the black toner developer and the other color toner developers, the voltage values written in the nonvolatile memory are different for each installed developing device.

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

When a copying instruction is given to the operation input unit 31, the CPU 3
0 gives copy instructions to each part. 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 developer has been consumed, and the toner concentration is gradually decreasing.

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

At this time, the detection output of the inductance sensor 34 is applied to one input terminal of the comparator 39. Also, C.P.
U30 monitors the type of the current Q device and provides an address signal V() along with a read control signal to the nonvolatile memory 37. Therefore, the other input terminal of the comparator 39 receives the readout signal from the nonvolatile memory 37. A sensor detection voltage is applied at a reference toner concentration depending on the type of developing device used.

The comparator 39 compares the voltages applied to both input terminals and outputs a voltage according to the difference between the two. Based on the output of the comparator 39, the toner replenishment instructing means 40 sends the developing device v! t
An instruction is given to the toner replenishing means 35 in 7 as to whether or not to replenish toner. The toner replenishing means 35 replenishes toner to the developer based on the above instructions. This results in
The toner concentration in the developer increases, and toner replenishment is performed until the toner concentration matches the reference value.

As described above, at the time of initial setting, the toner concentration of the developer at the standard concentration of each developing device is written in different storage areas of the nonvolatile memory, and the toner concentration of the developer at the time of image formation is written.
Since toner replenishment is performed by comparing the reference toner density read from the memory according to the type of developing device, the toner density can be maintained accurately at the predetermined concentration for each developing device. You can leave it there.

In the above embodiments, the developing device 7 has been described as being removable from the main body of the image forming apparatus, but the photosensitive drum can also be made removable from the main body of the copying machine to change the color when copying. Both the developing device and the photosensitive drum may be replaced each time.

(Effects of the Invention) As described above in detail, according to the present invention, at the time of initial setting, the toner a degree of the developer having the standard 'a degree of each developing device is written in different storage areas of the nonvolatile memory, and the Toner 1 degree control is performed by comparing the toner 81 degrees of the developer at the time of formation with the standard toner concentration read from the memory depending on the type of developing device installed. It is possible to realize an image forming apparatus that can accurately maintain toner density at a predetermined density for each developing device.

[BRIEF DESCRIPTION OF THE DRAWINGS] 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 a developing device, and FIG. 3 is a configuration diagram of the developing device and connector. FIG. 4 is a characteristic diagram of an inductance sensor, and FIG. 5 is a configuration diagram of a conventional electronic copying machine. 1... Photosensitive drum 7... Developing device 30...
・CPLJ 31...Operation input section 32...
-Display section 33...Toner remaining sensor 34...Inductance sensor 35...Toner replenishment means 36...A/D conversion switch 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-...Terminals 52...Color information display means Fig. 3 Fig. 4 iA; Return

Claims (1)

[Claims] an electrostatic latent image forming means for forming an electrostatic latent image on a photoreceptor;
A developing device that visualizes an electrostatic latent image using a developer containing toner, a transfer device that transfers the visualized image by the developing device onto a transfer paper, and a fixing device that fixes the transferred image. a color information display means disposed within the developing means and outputting information corresponding to the color of the toner; a toner concentration detecting means disposed within the developing means for detecting the toner concentration of the developer within the developing means; a non-volatile memory having a plurality of areas; a writing unit for writing the reference toner concentration of the developer into a predetermined area of the non-volatile memory according to the output of the color information display unit; and a write unit for displaying the color information during image formation. A readout means reads out a reference toner concentration of the developer from a non-volatile memory in accordance with the output of the means, and a toner concentration of the developer detected by the toner concentration detection means during image formation becomes equal to the reference toner concentration. An image forming apparatus for forming an image, comprising a toner density control means for controlling toner density as described above,
An image forming apparatus characterized in that at least the developing means is configured to be detachable from the image forming apparatus main body.