JPH02222977A - Copying machine - Google Patents

Abstract

PURPOSE:To precisely control toner concentration by storing reference toner concentrations corresponding to developers contained in different types of developing units in a copying machine main body and setting an appropriate reference toner concentration corresponding to each developer. CONSTITUTION:A developing unit identifying means 21 identifies the developing unit 2 loaded to the copying machine main body 1, namely, identifies the developer. The developer identification includes the color of the developer and the type of electrifying characters, etc. The reference toner concentration corresponding to the type of the developing unit 2, in other words, the reference toner concentration corresponding to the developer, is stored in the memory 13 of the copying machine main body 1, and when the developing unit 2 is loaded, the reference toner concentration corresponding to the unit (developer) is set. According to the set concentration, toner concentration is controlled. Thus, toner concentration is controlled according to the color of the mounted developer and the type of electrifying characteristics, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (AL Industrial Field of Application) This invention relates to a copying machine that develops an electrostatic latent image by adhering toner to it, and particularly to a control method for maintaining toner in a developing device at a constant density. Concerning improvements in methods.

(BL Conventional Technology) In general copying machines, images are formed using a two-component developer consisting of toner and carrier. The carrier is a magnetic iron powder of about 100 μm.

This developer is stored in a developer tank, and the toner is electrostatically attached to the latent image on the photoreceptor to perform development. When forming an image using such a two-component developer, it is necessary to maintain a constant depth in the developer tank in order to prevent variations in the density of the formed image. Toner concentration side that compares the toner concentration detected by the sensor with a preset reference toner concentration and automatically replenishes toner from the toner hopper if the detected toner concentration is low? 11 devices were used.

On the other hand, in recent years copying machines have come to use different types of developers, such as color toners and toners with different charging characteristics. These developers are stored by type in a developing unit (including a developer tank 1 and a toner hopper) that is detachably installed in the main body of the copying machine. Therefore, image formation can be performed using different types of toner simply by replacing the developing unit.

(C1 Problem to be solved by the invention) By the way, the toner concentration in the developer tank is i3 in the developer.
It is common to detect this by measuring the i-rate and use it as a substitute for the toner concentration to control the toner concentration. However, this magnetic permeability varies depending on the manufacturing lot even when the developer is new, and if the developer is of a different type (for example, when the type of coloring pigment is different), it will be affected by the coloring pigment, so it will vary depending on the type of developer. It will be different. As mentioned above, some copying machines in recent years are equipped with multiple developing units that can be detached from one copying machine. Correspondingly, a reference toner density (reference toner'tnR) must be set to perform density control. However, in conventional copying machines, such toner density control is not performed for each developing unit, and a constant reference toner density is simply stored in the copying machine body, and the same toner density is maintained regardless of developer lot or type. The toner concentration in the developer tank was controlled using the reference toner concentration.

In addition, when using magnetic permeability as a substitute for toner concentration, the magnetic permeability itself changes over time, and after a certain amount of time has passed after the start of use, the toner concentration may deviate from the actual toner concentration even if the toner concentration is controlled based on the reference toner concentration. There were times when I ended up.

In addition, developing units may be exchanged between multiple copying machines, or a developing unit installed in another copying machine may be installed in any copying machine, but in such cases,
If the reference toner density did not match, correct toner density control could not be performed.

Furthermore, the electrical characteristics of the toner concentration sensor (such as the size of the threshold level for converting analog output into two values)
For example, the development unit of black developer differs even in the same type of development unit (developer).
If you replace the developing unit with a black developing unit that was installed in another copying machine and leave it as is, the electrical characteristics will be different from the developing unit that was previously installed, so correct toner density control will be performed in this case as well. The problem was that it was not possible.

An object of the present invention is to store reference toner densities corresponding to developers stored in a plurality of types of developing units in the copying machine body, so that appropriate reference toner densities corresponding to each developer can be set. An object of the present invention is to provide a copying machine that can accurately control toner density.

Another object of the present invention is to provide a copying machine that can accurately control toner concentration by setting the reference toner concentration according to the type of developer in use, changes over time, and the like.

In addition, by making it possible to read out the standard toner density of the developer currently in use and the standard toner density setting parameters from the storage means, and writing these values into the storage means, the developing unit can be exchanged between copying machines. It is an object of the present invention to provide a copying machine that can accurately control toner density even when replaced.

Furthermore, by providing means for storing the electrical characteristics of the developing unit and means for detecting the electrical characteristics, it is possible to determine whether the newly installed developing unit matches the electrical characteristics stored in advance. It is an object of the present invention to provide a copying machine that can easily respond to, for example, alarm notifications when a developing unit having sensors with different electrical characteristics is installed.

(d>Means for Solving the Problems) According to claim 1 of the present invention, there is provided a toner hopper in which toner is stored, a developer consisting of toner and carrier, and toner replenishment from the toner hopper based on a reference toner concentration. In a copying machine in which a developing unit having a developing tank is detachably attached to a copying machine main body, the copying machine main body is provided with developer identification means for identifying the developing unit, and the copying machine main body is provided with a developer identification means for identifying the developing unit; a reference toner density storage means for storing a reference toner density corresponding to the type of developing unit; a reference toner density setting means for reading out and setting a reference toner density corresponding to the installed developing unit from the reference toner density storage means; It is characterized by having the following.

Further, in a second aspect of the present invention, a parameter storage means for storing a reference toner concentration setting parameter corresponding to a change over time of the developer, a means for detecting a usage time of the developer in use, and a reference based on the usage time. The present invention is characterized by further comprising means for reading and setting the toner concentration from the parameter storage means.

Further, in claim 3, according to claim 1 or 2, a read mode for reading out and outputting contents stored in the reference toner density storage means or the parameter storage means, and a reference toner density and The present invention is characterized by providing setting means for each writing mode in which a reference toner density setting parameter is written.

Furthermore, in claim 4, in any one of claims 1 to 3, the copying machine main body includes:
A sensor characteristic storage means for storing the electrical characteristics of a toner concentration sensor in a developing unit installed in the copying machine main body, and a means for detecting the electrical characteristics of the toner concentration sensor of the installed developing unit are provided. It is characterized by

<81 Effects> In the first aspect of the present invention, the developing unit identifying means identifies the developing unit installed in the copying machine main body, that is, identifies the developer. The identification of the developer includes, for example, the type of the developer, such as color band type characteristics. The standard toner density corresponding to the type of developing unit, that is, the standard toner density corresponding to the developer, is stored in the memory (storage means) of the copying machine, and when the developing unit is installed, the standard toner density corresponding to that unit (developer) is stored. A reference toner density is set based on the reference toner density, and toner density control is performed based on the reference toner density. Therefore, toner density control is performed depending on the color, charging characteristics, etc. of the loaded developer.

Further, in the second claim, since the reference toner concentration is set by a parameter depending on the usage time (change over time) of the developer, it is possible to control the toner concentration in accordance with the state of the developer at that time. This allows for accurate toner density control.

Furthermore, in the third claim, since the currently used reference toner density and parameters can be read in the read mode and those values can be freely written in the storage means in the write mode, for example, two copies can be stored. When trying to exchange the developing unit between machines,
Before removing the developing unit from one of the copiers, set it to read mode and read the standard toner density and variation of that developing unit. Then, when the developing unit is installed in the other copying machine, it is set to write mode and the read contents are written as they are. In this way,
Even if the developer tank is replaced, it can be easily handled.

Further, in the fourth aspect, the electrical characteristics of the developing unit currently in use are detected, and it is determined whether the electrical characteristics are the same as those stored in the storage means. If they are different, an alarm can be displayed or an error state can be set. It is also possible to store a plurality of electrical characteristics and reference toner concentrations corresponding thereto in the storage means, and read out and set the reference toner density that matches the detected electrical characteristics.

(f) Embodiment FIG. 1 is a block diagram of the main parts of a copying machine which is an embodiment of the present invention.

The copying machine main body 1 is controlled by CPU II.

]) 011 controls the entire copying machine based on a program stored in the ROM 12 in advance.

As shown in FIG. 2(A), a developing unit 2 is detachably provided in the copying machine main body 1. As shown in FIG. The copying machine main body 1 is provided with a connector 3, and the developing unit 2 is provided with a connector 4. When the developing unit 2 is attached to the copying machine main body 1, the connectors 3 and 4 are connected. FIG. 2(B) is a diagram showing a schematic configuration of the developing unit 7. Developing unit 2
The developer tank 6 includes a developer tank 6 that stores a developer consisting of toner and carrier, and a toner hopper 5 that stores replenishment toner for the developer tank 6-. A stirring roller 9 is provided in the developer tank 6 to frictionally charge the toner and carrier by stirring. Then, a magnet roller 7 supplies the charged toner to a photoreceptor (not shown). A toner concentration sensor 8 is provided above the magnet roller 7. The toner concentration sensor 8 detects the magnetic permeability in the developer tank as a toner concentration, converts the detected value into a voltage, and outputs it as an analog output.

If the toner concentration in the image tank detected by the sensor 8 is low (if the detected toner concentration is lower than the reference toner concentration), the toner replenishment roller 10 rotates to replenish toner into the developer tank. do.

The toner replenishing roller 10 is a half-moon-shaped roller that replenishes a predetermined amount of toner in one rotation. Note that the toner supply roller 10
．． Stirring roller9. The rollers such as the magnet roller 7 are rotated by a gear on the back (not shown) connected to a gear (not shown) on the main body of the copying machine, and the driving force is derived from the rotational force of the main motor of the main body of the copying machine. It is transmitted via a clutch.

In FIG. 1, the developing unit throat 2 has a dip <D for identifying the developer stored in the developing unit.
An IP) switch 21 is provided. Although the figure shows an example in which the TP switch 21 is provided so that three types of developer force numbers can be selected, this number is arbitrary. When the user switches the DTP switch in accordance with the developer, the copying machine main body 1 reads the state of the DI1) switch via the connector. In this example, three types of developer, black, red, and blue, can be identified. In addition, it may be possible to distinguish between developers of the same color but different charging characteristics.

The developing unit 2 has an output (analog output) proportional to the toner concentration output from the toner concentration sensor 8, and an RA,
A comparator 23 is provided to compare the control voltage stored in M13. The control voltage is a voltage value proportional to the standard toner concentration of the toner, and is a value set based on the toner concentration when new and various parameters described below. The control voltage is voltage generation circuit 2
After being analog-converted by 2, it is compared with the detected concentration voltage by a comparator 23.

By the way, when detecting the toner concentration by substituting the magnetic permeability of the developer for the toner concentration, it is necessary to consider the change in magnetic permeability over time. In other words, as shown by the solid lines in FIGS. 3, 4, and 5, when the control voltage is kept constant (the actual toner concentration in the developer tank as well as the number of images formed will vary depending on the detected toner concentration). Even if (magnetic permeability) is - constant, it may decrease or increase.In these figures, the toner concentration on the vertical axis indicates the actual toner concentration.Such toner concentration (magnetic permeability) Figure 3 (B).

As shown by the solid line in Figure 4(B), when toner density control is performed using a nearly constant control voltage, the difference between the image formed when the developer is new and after a certain number of images have been formed is There is a problem that the quality differs. Therefore,
By changing the control voltage as shown by the broken lines in FIGS. 3(B) and 4(B) according to the number of images to be formed, the broken lines in FIGS. 3(A) and 4(A) The actual toner density can be kept constant as shown in the figure, and the image quality can be maintained. The broken line in Figure 3 (B) shows that when the control voltage is changed stepwise for each certain number of sheets,
The broken line in FIG. 4(B) shows an example in which the control voltage is changed finely. In addition, in Figure 5, if the control voltage is lowered when a predetermined number of images (approximately 90,000 images) have been formed, the actual toner density can be prevented from becoming too high as shown by the broken line. can. Note that it is preferable to replace the developer after approximately 20,000 to 50,000 sheets have been used, although this varies depending on the developer. This is because the carrier deteriorates with use and the charging characteristics deteriorate.

The state of change in toner density over time as described above differs depending on the developer (type of color, etc.). Further, as described above, the lifespan of the developer also differs depending on the developer.

Therefore, data for setting the control voltage (reference toner tM degree) according to the type of developer is stored in the RAM 13.

FIG. 7 is its memory map. As shown in the figure, the number a of sheets to which the control voltage is shifted and its rate of change,
The lifetime number of sheets of developer is stored in correspondence with the type of developer. Among these data, the control voltage shift number and rate of change are parameters for changing the Yotowar voltage (reference toner density). The control voltage changes based on this parameter.

As mentioned above, the developing unit 2 is detachably installed in the copying machine main body l, and if a developing unit 2 containing a different type of developer is installed, an image can be formed using a different type of developer. be able to. Since such developing units contain different types of developer, their control voltages also differ. Therefore, the control voltage corresponding to each developing unit (developer) is stored in the memory (RAM 13) of the main body of the copying machine.

FIG. 6 is its memory map. Note that in this embodiment, only developers of different colors are used, so that the developers of different colors, that is, the developers are identified. However, for example, when developers with different colors and charging characteristics are used, the charging characteristics are also identified. You must do so.

As shown in the figure, the color of the developer stored in the developing unit, the life counter corresponding to that developing unit,
A control voltage and a matching voltage are each stored. A control voltage (reference toner density) corresponding to the type of developing unit is stored in this RAM 13.

The color of the developer is input from a DIP switch 21 provided in the development unit. The life counter stores the number of copies made by the developing unit, and is reset when the developer is replaced.

The matching voltage stores the detected value of the toner density sensor of a new developer, and is reset when the developing unit is replaced, so that the voltage corresponding to the new developing unit is stored. The control voltage is initially equal to the matching voltage, and as the number of copies increases, it is set based on the control voltage shift number and rate of change shown in FIG. This control voltage is sent to the developing unit and compared with the detected density voltage in the comparison circuit 23.

In such a configuration, the matching voltage is set as follows. When the developing unit is installed in the main body of the copying machine with new developer stored therein, the toner concentration sensor 8 measures the toner concentration (magnetic permeability) and inputs a voltage proportional to the toner concentration to the child terminal of the comparison circuit 23. Meanwhile, CPU II sends a variable voltage to the developing unit. The voltage is D/A in the voltage generation circuit.
The converted signal is input to one terminal of the comparison circuit 23. As a result, the voltage value when the variable voltage and the concentration detection voltage match is stored in the RAM 13 as a matching voltage.

A control voltage is set from this matching voltage and the parameters shown in FIG. 7, and is stored in the control voltage field shown in FIG. 6.

The CPU II has an operation panel control section that includes a display section, print switch, etc.] 4. Toner density adjustment mode key 15
, a clutch 16 for transmitting driving force to the toner supply roller 10, a main motor, and the like are connected. The toner density adjustment mode key 15 is provided next to the mounting portion of the developing unit 2 (see FIG. 2(A)), and operation of this key starts the matching voltage setting operation.

FIG. 8 is a flowchart showing the processing procedure for toner density control.

When the developing unit 2 is installed in the copying machine main body 1, its unique type (color) is read depending on the state of the DIP switch 21 (nl). If the adjustment mode key 15 of the toner density sensor is turned on, after clearing the matching voltage and control voltage stored in the RAM 13,
As described above, the coincidence voltage is measured and stored in the coincidence voltage storage area, and the coincidence voltage is set and stored as a control voltage (n4-=n5).

When the adjustment mode key 15 is not operated, it is assumed that the mode is copying and the process proceeds to n6, but if the control voltage is not stored in the RAM 13 at this time, a display prompting the setting of the adjustment mode is made at nl. This can prevent errors in toner density control due to forgetting to set the control voltage.

At n8, the number of sheets in the life counter is compared with the number stored in the parameter memory shown in FIG. 7. At this time,
Of course, the parameters for each developing unit (each developer color) are referenced. For example, if the color of the developer is black, the topmost parameter is referred to.

If the current number of sheets does not correspond to any part of the parameter memory, the current control voltage is output to the developing unit 2. Then, the toner concentration detected by the toner concentration sensor 8 is compared with the control voltage, and if the detected concentration is lower, the clutch 16 of the toner replenishment roller 10 is turned on and the toner replenishment roller is rotated only once to replenish the toner. (n9→nlo, n1l). Further, when the number of sheets on the life counter reaches the shift number a, the control voltage is shifted (n12). Furthermore, when the number of sheets on the life counter reaches the number of sheets that have reached the end of their lifespan, it is time to replace the developer, and a flag is set (n13). When this flag is set, a display prompting the user to replace the developer is displayed on the operation unit, and the user replaces the developer in accordance with the display. After replacing the developer, when the adjustment mode key is operated, the flag and life counter are reset, and the control voltage is cleared (n
3. n4), new match voltages and control voltages are set.

In this embodiment, r developing unit identifying means j is DIP
nl to read the switch corresponds to "Reference toner density j
corresponds to the control voltage, and "reference toner density setting means" corresponds to n9. Further, the means J for detecting the usage time of the developer during r use in claim 2 is used in the determination of n8, and corresponds to a sheet number counter arranged in the memory in the CPU, and the reference toner density is stored from the parameter storage means. The means to read and set is n8. n9 is compatible.

FIG. 9 shows an embodiment corresponding to claim 3. In this embodiment, the control voltage is used for reading and writing to the memory.

FIG. 9(A) shows the control voltage reading operation.

At n20, the DIP switch is read to determine the developing unit, and at n21, if the control voltage reading mode (memory read mode) is selected, the control voltage value of the developing unit is read from the memory and displayed on the display. Note that the display provided on the operation panel is used.

FIG. 9(B) shows the control voltage writing operation.

The currently installed developing unit is determined at n30, and if the control voltage input mode (memory write mode) is selected at n31, the control voltage value is input at n32. The input control voltage value is written into the memory as described above, for example, in the two copying machines A.

With black developing units a and a' installed in each of A', the developing units of copying machine A are moved from a to a'.
When attempting to change to the control voltage, first set the copying machine A' to the control voltage reading mode with the developing unit a' installed in the copying machine A', and read the control voltage of the developing unit a'. . At this time, it is desirable to note down the value of the control voltage read. Next, the developing unit No. 1 of each copying machine A, A'
Remove "a+" and attach developing unit a to copying machine A.
’ is installed. Then, the copying machine A is set to the control voltage input mode, and the control voltage of the developing unit a' read earlier is inputted using the key.

In this way, the developing unit of another copying machine can be used in the copying machine, and even if the developing unit is exchanged between two copying machines, the above operation can be performed on each copying machine. You can easily respond by just doing it to the machine. In the above embodiment, the data stored in the memory is the control voltage (reference toner density), but it is also possible to add data stored in the parameter memory.

10 and 11 show an embodiment of claim 4. FIG.

Even if the developing units are of the same type, the electrical characteristics of the internal toner density sensor (for example, comparator 2 in FIG.
It is normal for the control voltage to vary slightly depending on the threshold voltage (3). In this embodiment, a means for detecting the threshold voltage is provided, and a means for storing the threshold voltage of the developing unit that should originally be installed is also provided. An error message is displayed when the developing unit of the copying machine is installed.

FIG. 10 is a configuration diagram of the embodiment. In the configuration, the first
The difference from the diagram is that swi, sw2, a switch control unit 30 that controls these switches, a variable voltage generator 31 that is controlled by cpuii, and a voltage detection circuit 32 that detects the voltage are newly provided. be.

FIG. 11 shows the operation. First, if the toner density adjustment mode is set in n40, the developing unit is detected in n41, and the threshold voltage of the correct toner density sensor in the developing unit installed at that time is detected in n42.

The method of detecting the threshold voltage is to turn on SW1 and SW2 in FIG. 1, operate the variable voltage generator 31, and use the voltage detection circuit 32 to detect the output of the variable voltage generator when the output of the comparator 23 is inverted. To detect. The voltage at that time is the threshold voltage of the comparator 23, that is, the threshold voltage of the toner concentration sensor. This voltage is stored in a predetermined area of the RAM 13. At the same time, the toner concentration sensor adjustment as shown in FIG. The control voltage and threshold voltage are stored bare in the RAM 13.

When the above operations are completed, SW1 and SW2 are turned off. Then, when a new developing unit is installed, n5
0 identifies the developing unit, n51 detects the threshold voltage of the developing unit, and f15
Check with 2. At that time, if the threshold voltage is different from the one stored in the memory, an error message is displayed indicating that the developing unit is from another copying machine.

Note that by storing threshold voltages corresponding to multiple developing units in advance and storing control voltages based on the type of developer and the magnitude of the threshold voltage in memory, it is possible to Of course, when the developing unit is replaced, it is also possible to detect the type and threshold voltage of the developing unit, read out and set the corresponding control voltage.

Further, in addition to the above-mentioned threshold voltage, the electrical characteristics may include a voltage across a constant such as a resistance.

(Effect of the Cloudy Invention As described above, in the invention of claim 1, the reference toner density (control voltage) for each developing unit is stored in the copying machine main body, and it can be stored simply by installing the developing unit. Since the reference toner density corresponding to the developer is set and toner density control is performed, appropriate toner density control can be performed, and as a result, the quality of the formed image can be maintained in a good state.

Further, in the invention of claim 2, since the reference toner concentration is set according to the change in the developer over time, it becomes possible to perform accurate toner concentration control according to the change in the developer over time, and the formation Image quality can be improved.

Furthermore, the invention of claim 3 has the advantage that it is easy to exchange developing units between a plurality of copying machines and to use the developing units of other copying machines during maintenance.

Furthermore, in the invention of claim 4, since even differences in threshold voltages are strictly checked, there is an advantage that the formed image quality can be made more precise.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a copying machine which is an embodiment of the present invention.
FIG. 2(A) is a diagram showing the state in which the developing unit is installed in the copying machine, and FIG. 2(B) is a diagram showing the configuration of the developing unit. In addition, Fig. 3 (A), Fig. 4 (A), and Fig. 5 are diagrams showing the relationship between toner density and the number of copies;
FIG. 4(B) and FIG. 4(B) are diagrams showing the relationship between the control voltage and the number of copies. Further, FIG. 6 is a memory map of an area in the RAM for storing developing unit data, FIG. 7 is a memory map of an area for storing developer parameters, and FIG. 8 is a flowchart showing a processing procedure for toner density control. Further, FIG. 9 is a diagram showing an embodiment of the invention according to claim 3,
FIG. 10 and FIGS. 11(A) and 11(B) are diagrams showing an embodiment of the invention according to claim 4. 1-copying machine body, 2-developing unit, 3.4-connector, 8-toner density sensor, 21-dip switch.

Claims (4)

[Claims] (1) A developing unit having a toner hopper that stores toner and a developer tank that stores developer consisting of toner and carrier and that replenishes toner from the toner hopper based on a reference toner concentration is installed in the main body of the copying machine. On the other hand, in a removably installed copying machine, the copying machine body is provided with a developer identification means for identifying the developing unit, and the copying machine body is provided with a reference toner that stores a reference toner concentration corresponding to the type of developing unit. 1. A copying machine comprising a density storage means and a reference toner density setting means for reading out and setting a reference toner density corresponding to the installed developing unit from the reference toner density storage means. (2) A developing unit having a toner hopper that stores toner and a developer tank that stores developer consisting of toner and carrier and that replenishes toner from the toner hopper based on a reference toner concentration is installed in the main body of the copying machine. In contrast, in a removably installed copying machine, a parameter storage means for storing a reference toner concentration setting parameter corresponding to a change in developer over time, a means for detecting a usage time of the developer in use, and a means for detecting the usage time of the developer in use; A copying machine comprising: means for reading out and setting a reference toner density based on the parameter storage means from the parameter storage means. (3) In claim (1) or (2), a read mode for reading and outputting contents stored in the reference toner concentration storage means or the parameter storage means; A copying machine characterized by being provided with setting means for each writing mode for writing toner density setting parameters. (4) In any of claims (1) to (3),
A copying machine main body includes a sensor characteristic storage means for storing electrical characteristics of a toner density sensor in a developing unit mounted on the copying machine main body, and a means for detecting electrical characteristics of a toner density sensor of the mounted developing unit. A copying machine characterized by being provided with.