JPS59135483A - Image forming device - Google Patents

Abstract

PURPOSE:To detect a stable and exact state of image formation and to properly control image formation by delaying detection action using a means for detecting image formation conditions. CONSTITUTION:Currents flowing from the conductive substrate Al 103 of a photosensitive drum to the ground, from it to the substrate Al 103 due to discharge with chargers 2, 4 through resistors R1, R2, diodes D1, D2 are measured, and sent a multiplexer MPX, an A/D converter Vc, etc. to CPU, and image formation conditions are detected. In this case, the CPU delays detection action in response to a built-in timer, and detects stabilized image formation conditions to control image formation, after the image forming means of the chargers 2, 4 and the photosensitive drum, etc. has started action, or changed output, and further prescribed time length has elapsed. Therefore, image formation is exactly controlled without being affected by scattering, etc. of characteristics of constituent parts.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming apparatus capable of performing stable image formation.

In projection devices that use electrophotographic technology, the potential on the surface of the photoreceptor that has the greatest effect on the visible image is the ambient temperature.

Humidity ((', 'j Affected by the deterioration of the nine bodies, (
i) Electric? :(It was difficult to maintain the predetermined position 15 due to variations in the installation of the charging transformer and variations in the voltage of the charging transformer.

Conventionally, as a countermeasure to this, there is a method in which the image forming strip f'F, for example, detects the surface potential of a photoreceptor or the current of a charger and controls the voltage of the charger to obtain a predetermined potential.

However, the output of the charger etc. is unstable immediately after the start of operation, and even if the image forming conditions are detected during this period, it cannot be detected accurately, and it is difficult to obtain a proper image forming output.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an image forming apparatus capable of accurately detecting an image forming state and appropriately controlling the output of an image forming means.

That is, the present invention includes an image forming means for forming an image on a recording medium;
The image forming means has a detection means for detecting an image forming state by the image forming means, and a control means for controlling the image forming means according to a detection output of the detection means, and the control means controls the image forming means after the start of operation of the image forming means or a change in the output thereof. The detection operation by the detection means is delayed by the time i in the latter term.

The present invention will be explained below with reference to the drawings. First, an example of the copying process will be explained with reference to the drawings. First, the photoreceptor 1 (Mylar 101.cds102+ 4) is charged primarily by the charger 1.
'+TFB substrate 106) The surface is exposed to a light image through the lens system 5, and at the same time an electrostatic image is formed along with the discharge of the static eliminator 4. If necessary, the entire surface is exposed to light using a lamp to increase the contrast of the latent image, and then developed. A device 6 forms a visible image, and a paper feed roller 7 transfers the visible image to a transfer paper 9 fed from a cassette 8 (by a transfer charger 10), and a separation roller 11 transfers the visible image to a photoreceptor. It is.

In the present invention, prior to such a copying process, the charging state of the photoreceptor due to conditions such as the atmosphere is detected.

That is, in the present invention, the bright area on the surface of the photoreceptor.

The charge landscape induced in the dark area is related to this four-electric substrate metal, so instead of measuring the potential on the photoreceptor surface,
A stable surface potential can be obtained by controlling the discharge flow rate of the charger using this current value.

By providing an electrically independent check zone around the photoreceptor that is constantly exposed to light, the charged state can be detected even during copying. A current 10 flows from the conductive substrate inside the photoreceptor drum to the ground of the ML flow discharged by the charger, and Amount of current flowing from the ground -
In order to detect both components, diodes D1 and D2 are installed in opposite directions on the conductive substrate inside the photoreceptor drum, and furthermore, in order to detect the electric current value of Connect resistors R1 and R2 and connect them to ground.

This primary charger 2. The current value + (ie, voltage E+) with the exposure rung AC charger 4 turned on.

It becomes. In Figure 6, the zero point indicates the amount of current of the component from the primary charger, and furthermore, the current of the component of the pulsating flow part Indicates that they are superimposed, and a 0 point indicates the accent of the ○ component of the AOg [apparatus].

The present invention i"l: Measure the voltage across R1 and R2,
■.

Control O. That is, the voltage R+ appearing at R1 is the voltage i when the pulsating flow component is oscillated using a commercial frequency or an oscillator.
Since it appears at a frequency of 9+00 Hz, the minimum value of the minutely sampled instantaneous values over -periods or more corresponds to the prodigal flow from the first arrow. Also, the voltage E- appearing at R2 can be determined by converting the polarity and determining the voltage E-, which corresponds to the discharge flow rate of the Q component from the vessel, by subtracting the minimum value from the maximum value.

The maximum value of the power sampled in the same way (this indicates the electric A value of the AC charger's ○ component) is 0 Here, the reason why the AC charger's current amount is separated into ■ component and ■ component and sampled. The purpose of this is to set these to appropriate values because the difference in these components causes the charge on the surface of the photoreceptor by the primary charger to be discharged on all four parts.''And point ■
And one point ■.

If the value at point @ is not at the appropriate value, feedback is applied to the high-voltage transformer of each bandg generator according to the measurement, and the input voltage is raised or lowered to the proper level. In the figure, V1 is a voltage converter that converts the detected voltage jA and voltage 10- into positive voltage E-.

MPX is a multiplexer for sampling input E+rB- with AD converter Va, and AD converter VC converts the input voltage into digital data and outputs it to the next stage control unit cptr. The CPU is an AD converter, memory ROM,
Reads, decodes, and adjusts input and command data from RAM.

It is a central control unit with functions such as processing logical operations,
ROM is a dedicated memory for ML output that stores the procedure (two programmers) for operating this control circuit for the above purpose, RAM is a writable memory that temporarily stores data for the program processing, 0ut1 is the ■ component An output device that outputs a signal that sets the voltage of the AC transformer HVTi to supply current.

Similarly, AC transformer HVT of each component of Q11t21"
2, 1a, pressure, ' An output device that outputs a signal to set the voltage of the DC transformer H'' + 'T3, OUT is the motor that rotates the photosensitive drum, a light lamp, D (1!
) An output device that outputs an output signal that controls the drive (on, off) of the transformer AC transformer, n1 and 2 are copies -
O DA 1~ is an input device that inputs the drum position (home) signal of the clock signal for executing -1000-ma, the registration signal of the transfer timing, and the signal of detecting the state of the copying machine (detection of toner density, etc.) 5 is a D-A converter that converts the digital signal from each Out 1 to 5 into an analog quantity and outputs the voltage to the AC transformer HVT 1 to 5, and the output timing is determined by the signal from Out 4 □ D 5
+' is a diode for voltage component separation 0 above ROM
A program for controlling the potential according to the rectangular flowchart shown in Fig. 6 is stored in the RAM.The above RAM stores in advance the AC optimum potential, the DC optimum potential, and the number of samplings. O'dL source input and CPU explained in operation steps (hereinafter referred to as SP)
reads the programs in the ROM sequentially and starts controlling execution. First, □out 4 is a signal that turns on the designated main motor via an address designation signal bus (referred to as an address bus).For example, if Out 4 can output 8 bits in parallel, the main motor output terminal is 1 and the other output terminals are 0. A certain code signal is transmitted through a data bus (hereinafter referred to as data bus).
Transfer to ut4 (SPl) o Next, the CPU operates a timer for several seconds to pause the number of program executions until the main motor reaches a constant speed, that is, the drum rotation becomes stable.
) o When the time is up, the CPU transmits a code signal such that Out 4 turns on the power of the primary high voltage transformer, g-light lamp, and AC high voltage transformer to 0 out 4 via the data node (S*-6)O+1] and Activate the timer and press C on the arrow.
The PU activates the multi-breathing arm according to the control signal α.
Open the gate for + input signal output.

This signal is sequentially sampled by the A-D converter (described later), and the wrinkle-sampled signal is converted into a binary code and read into the CPU via the data node (Sr1).The data E+ read for each sample is if is compared with what is stored as the highest value in RAM K (cp-6), and if it is less than the minimum value, it is compared with what is stored as the maximum value (5p-8), while if it is less than the minimum value. If it is smaller, it is re-stored in RAM as a new maximum value (sp-7) 9P9) Reading (sampling) and comparing data such as 0 or more 'If the processing cycle in the O-hole CPU, which is performed over one AC cycle by the fc AC transformer, is approximately 200 μs, then the process is equivalent to performing the process 100 times, that is, once. Each time the RAM is set to 1, it goes on to the next step (
Fir-10) O In the end, the 0 point in FIG. 3 is read and stored as the minimum value and the ■ point as the maximum value.

Then, the CPU ij subtracts the maximum value and minimum value, temporarily stores this result (SP 11), and selects the r flag FI.
agsu The subtraction result is a desired value (pre-stored in RAM), which is 1etθp lower than the conventionally set value.
A high or low value is applied to OUT 1 via the data bus, which is converted to analog by the DA converter to raise or lower the voltage of the AC high voltage transformer. The minimum value is D
This shows the discharge current value from the C transformer, so if this value is different from the desired value, use the same method to change the output device OUT 3.
By giving a value 1 stop higher or lower to ', the DC high voltage transformer is raised or lowered via the D-A converter (5
P-1/1, 17, 18.19). 5P-15.

After 19 the flag is reset. And the cpu is ■
Repeat operations 2 or more until the values of point and
The process returns to SP-4 again via 20, and since the flag is set at a proper value, the process proceeds to the next step. Next, AC
Value of Q component of Lfr: voltage converter.

The sample is sent to the A-D converter via the multi-reflector and read repeatedly over one period (5P-
21, 22, 23, 24), if its maximum value, that is, the value at the 0 point, is not equal to the desired value, the output device OUT
Transfer a value 1etθp higher or lower than the conventional value to 2 and apply it to the ACC positive pressure transformer 2 gold (5p-2
5, 26, 27, 28). Then repeat this until it becomes a proper value (5P-29) C1f, payt -' in Figure 5;
As shown in.

(aJ + (Jυ, if the ■ point is 4 points at the appropriate value,
The primary high voltage transformer, exposure lamp + AC + 1i1i voltage transformer are turned off, cpul''l: Next, the operator is on standby (sp-+o), following instructions from the operator.
The timer 5P-4, 290 in FIG. 4 is provided to wait for sampling until the voltage is stabilized after voltage application is started or varied. From the flowchart in FIG. 4 above, it is easy for a person skilled in the art to create program steps using a dedicated instruction code using a general-purpose micro convenience store user (μ-COM4.LN: Go 8080, etc.). Steps are omitted. The timer records the timer time in advance in the RAM as a code.
This can be done by providing a loop that sequentially judges whether the code has decreased by 10 or not, but it can be done by providing an external timer means to control this in the control circuit. It is also possible to start a timer with Out and detect time-up with -.

As described above, according to the present invention, sampling of image forming conditions is delayed for a predetermined period of time after the start of operation of the image forming means or after a change in its output, so accurate detection is possible, and thereby proper zero-port, one-image formation is possible. It becomes possible to obtain output.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the copying process, Fig. 2 is a control circuit diagram of the surface potential stabilizing device according to the present invention, Fig. 6 is a waveform diagram of the detected potential in Fig. 2, and Fig. 4 is the same as Fig. 2. 2 is a flowchart showing the control process for detecting current on the component side, and in FIG. 2, 1 is a photoreceptor, 2 is a primary zone device, 4 is an exposure-simultaneous static neutralization: Fii, Di, and D2 are component-side current detection diodes, and MPX is a multiplexer. Procedural amendment (method) 1. Indication of the case Patent Application No. 138542 of 1982, Name of the invention Image forming device 3, Person making the amendment Relationship to the case Patent applicant address Ota-ku, Tokyo Shimomaruko 3-30-2 name (100
)Representative of Canon Co., Ltd. Ryu Kaku 3 Part 4, Agent address: 130-25 Domaruko, Ota-ku, Tokyo 146, Amendment Order No. 1 January 31, 1980 El (Shipping date) 6, Subject of amendment Description and Drawing 7, pages 5 to 15 of the description of the amendment, and engraving of Figure 34 of the drawings (
No change in content) ・Charged photoconductor l (Mylar 101.Cd
5102, conductive substrate 103) The surface is exposed to a light image through the lens system 3, and at the same time, an electrostatic latent image is formed with the discharge of the static eliminator 4, and if necessary, the entire surface is exposed with a lamp to form the recorded latent image. The contrast of the image is increased, a visible image is formed in the developing device 6, and the transfer paper 9 is fed from the feed roller 7 from the feeder 8.
-1- The rotation image is transferred by a transfer charger 10, the transfer paper 9 is separated from the photoreceptor 1 by a separation roller 11, and further sent to a fixing device 12 consisting of a fixing roller to be fixed and discharged to a tray 13. It is something to do. In the present invention, prior to such a copying process, the state of charge 71'B caused by conditions such as the atmosphere on the photoreceptor is detected. That is, in the present invention, the amount of charge induced in the bright and dark areas of the photoreceptor surface is in a completely corresponding relationship with the current value flowing out or flowing through the conductive substrate. By controlling the discharge flow rate of the charger based on this current value, instead of setting the potential at All+,
It is possible to obtain a stable surface potential. If an electrically independent check zone that is constantly exposed to light is provided around the photoreceptor, the charged state can be detected even during copying. FIG. 2 shows an embodiment of the invention. A DC primary charger 2 and an AC charger 4 having an optical path from an exposure lamp are arranged along the circumference of the photoreceptor drum. The conductive substrate inside the photoreceptor tram is arranged so that both components of the current flowing into the ground of the current discharged by the charger from the conductive substrate inside the photoreceptor tram and the current flowing out from the ground can be detected. Insert the old diode D2 in the opposite direction to q:, and connect resistors R1 and R2 to the ground at the end of the tie auto to detect the current values of y and y. This current value when the charger 2 and fog light lamp AC charger 4 are turned on (that is, the voltage E-)
), I- (i.e. pressure E-) is Par in Figure 3.
It becomes like t-A. , In Figure 3, the 0 point indicates the amount of current of the I component from the primary charger, and the pulsating flow part [with] above this is the superimposed current of the ■ component of the AC discharger. The zero point indicates the current amount of the e component of the AC charger. The present invention measures the voltages across R1 and R2. Control ◎. That is, since the pulsating current component appears at a commercial frequency or a frequency of several 100 Hz oscillated using an oscillator, the voltage E appearing at R1 is the minimum value of the instantaneous values minutely sampled over a period of - The value obtained by subtracting the minimum value from the maximum value corresponds to the discharge flow rate of component (2) from the AC charger. Furthermore, if the voltage E- appearing at R2 is measured after converting the polarity, the maximum value of the samples sampled in the same manner will indicate the current value of the e component of the AC charger. Here, the reason why the amount of current of the AC charger is separated into the ■ component and the θ component and sampled is because the difference in these components causes the charge carried on the surface of the photoreceptor by the primary charger to be discharged in the bright area. This is to set these to appropriate values. "And if the values at point ■, point ■-■, and point
Lower the input terminal to the appropriate value. A control example embodying the above two will be explained using a circuit using a microcomputer. In the figure, v1 is the detected negative voltage [
MPX is a voltage converter that converts the input terminal to positive voltage E-, MPX is a multiplexer that samples the input E- and E- with the An converter VC, and the AD converter VC converts the input terminal to digital data and supplies it to the next stage control section. Output to CPU. CPU is A
It is a central control unit that has the function of reading and decoding manual and command data from D converters, memory ROM, and RAM, and processing addition/subtraction, logical operations, etc., and ROM uses this control circuit for the above purpose. Read-only memory that stores the operating procedure (program), RAM is a writable memory that temporarily stores data for the program processing, Out 1 is the voltage of ACh lance HVT 1 for supplying the current of the ■ component. Similarly, Out 2 and 3 are output devices that output signals that set the voltage of each e component (AC transformer) IVT 2 and DC transformer HVT 3. Out is a device that outputs a signal that sets the voltage of the DC transformer HVT 3. motor, exposure lamp, DC transformer A
An output device that outputs an output signal that controls the drive (on, off) of the C transformer, Inl, 2 is a clock signal for executing the copy sequence, a drum position (home) signal, a transfer timing register) signal, and a copying device. This is a human-powered device that inputs a signal that detects the state (detection of toner concentration, etc.). DAI-3 is a D-A converter/hatter that converts the digital signal from each Out 1-3 into an analog quantity and outputs the voltage to ACI-Lance HVT 1-3, and outputs it by the signal 5) from Out 4. The timing is determined. D3゜4
is a diode for separating voltage components. The above-mentioned ROM stores a program for controlling the upper level according to flowchart 1 as shown in Fig. 3.The RAM contains the optimal potential of 8C, the Q' level, and the optimal potential of DC, as well as sampling. The number of times is stored in advance.゛Operation step (
(hereinafter referred to as SP). When the power is turned on, the CPU sequentially reads the programs in the ROM and starts control execution. First, Out 4 is sent to the address designation signal rat line (referred to as the address bus) to send a signal that turns on the designated main motor, for example, Out 4 is the 8-bin ]
・If parallel output is possible, the main motor output terminal r should be 1. A code signal whose other output terminal is 0 is transferred to 0ut4 via the data IfJ line (hereinafter referred to as data path) ('
5P-1). Next, the CPU operates a timer for a few seconds to suspend program execution until the main motor reaches a constant speed, i.e., the i-ram rotation becomes stable (SP-2). A coat signal that turns on the 11j power of the transformer, exposure lamp, and AC high voltage transformer is transferred to Out 4 via data bus 1 (
SP-3). Activate the 1-time timer and wait for the L power supply to stabilize (SP-4). ;Suddenly, the CPU uses the control signal α to switch the multiplexer MPX
Activate to open the gate for outputting the input signal of E+, and
- Sample this signal sequentially using a D converter (described later)
Then, the sampled signal is converted into a binary code and read into the cPU via the data bus (5T-5). The data E-1 read for each sample has already been stored in the RAM.
- compared with what is stored as a value (5p-e)
If it is smaller than the minimum value, it is compared with what is stored as the maximum value (SP-8); if it is smaller than the minimum value, it is stored in RAM as a new minimum value (SP-8). 5P-7). If it is larger than the maximum value listed in -1-, it is stored in the RAM as a new maximum value (SP
-ill). The reading (sampling) and comparison of data as described above is carried out in the AGI known by AC Lance. In other words, if the processing cycle in the CPU is approximately 200 seconds, it is equivalent to performing the process described in "-" 100 times. That is, each time it is subtracted from the memory value (100) in the RAM, it is determined whether the value becomes 0 or not, and the process proceeds to the next step (SP-10
). In the end, read and record the 0 point in Figure 83 as the minimum value and the 0 point as the maximum value. Then, the CPU subtracts the maximum value and minimum value and temporarily stores this result (SP-11).
Set the flag (5P-111). Flags are used to determine branches in program execution and are 5P.
−17, indicates the Yes direction. The subtraction result is the desired value (R
If it is not equal to the proper value pre-stored in AM), specify the output device Out l and give a value 15 tep higher or lower than the conventionally set value to Out l via the data path, and this -A converter converts it into analog and lowers the voltage of the AC high voltage transformer (SP-12, 13, 14, 15).

Claims (1)

[Claims] The image forming means includes an image forming means for forming an image on a recording medium, a detecting means for detecting the image forming means by the image forming means, and a control means for controlling the image forming means according to a detection output of the detecting means, An image forming bag F'1° characterized in that the detection operation by the detection means is delayed for a predetermined period of time after the start of the operation of the image forming means or after a change in the output thereof.