JPH0152751B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a copying apparatus that forms a variable magnification image on a photoreceptor.

[Prior Art] In conventional slit exposure type copying apparatuses that perform document exposure scanning by moving the document and optical system relative to each other, one of the technical factors that prevents speeding up is the document exposure scan speed. . The number of copies per unit time in full-size copying when performing forward exposure scanning of originals can be approximately expressed by the following equation.

N=V/(l _p +l _p +l _r +l _l ) (1+1/n) N: Number of copies l _p : Document length l _p : Run-up distance l _r : Reversal position distance Including exposure slit width l _l : Movement Distance conversion value of direction switching loss time V: Photosensitive drum circumferential speed n: Speed ratio to forward speed during backward movement, for example, A4 size 210mm x 279mm 1 minute 40
In a copier with a copying speed of 1 sheet, each constant is l _p =
210 mm, l _p = 40 mm, l _r = 10 mm, l _l = 10 mm, n = 2 (double speed return), the photosensitive drum circumferential speed V is V = 270 mm x 1.5 x 40 sheets/60 sec = 270 mm/sec, and in this case Scan speed is 270 during forward movement.
mm/sec When double movement is performed, it becomes 540mm/sec.

Therefore, in order to increase the copy speed N, it is necessary to increase V, but if you try to increase V, problems such as image blurring and wear due to the impact when reversing may occur, and some measures or measures must be taken to prevent this. Cost increases will become necessary. However, especially for copying machines equipped with a reduction function, the scanning speed must be increased by the reciprocal of the reduction/linear magnification. When equipped with a normal reduction function, the circumferential speed of the photosensitive drum is determined by taking into account the scan speed during reduction copying. The peripheral speed of the drum decreases.

Further, when the photosensitive drum is rotated at high speed when the power is turned on, there is a risk that the blade for removing residual toner on the photosensitive drum and other contacting members will be severely worn, which may shorten the life of the photosensitive drum.

Further, it has been proposed to reduce the operating speed of each mechanism of the copying apparatus to prevent noise when the apparatus is in a ready state and in a state other than when copying.
(Japanese Unexamined Patent Publication No. 52-68424) However, in JP-A-52-68424, since the operating speed is increased at the time of copying operation, the surface condition of, for example, the photosensitive drum changes rapidly, causing potential unevenness and latent images. There was a risk of defects occurring.

[Objective] The present invention has been made in view of the above points, and it is an object of the present invention to provide a copying apparatus in which the surface condition of the photoreceptor is stabilized as much as possible when the power is turned on, and high-quality copying can be performed.

That is, the present invention includes a scanning means for exposing and scanning an original image, and a charging means for corona charging a photoreceptor, and forms the original image exposed and scanned by the scanning means as a toner image on the photoreceptor, and transfers it to a transfer material. various process means for transferring the toner to the photoreceptor, a blade means for removing toner on the photoreceptor and cleaning the surface of the photoreceptor, a detection means for detecting the surface potential on the photoreceptor, and a variable magnification ratio. and a control means for controlling the operation of the scanning means and the photoreceptor to perform a desired variable magnification copying operation based on the variable magnification input from the input means, the control means comprising: scanning speed changing means for changing the scanning speed of the scanning means based on the magnification inputted from the inputting means; and a scanning speed changing means for changing the scanning speed of the scanning means based on the magnification inputted from the inputting means; rotational speed changing means for setting the rotational speed of the photoreceptor to a predetermined low rotational speed when a specific magnification ratio other than equal magnification is input from the input means; After turning on the power, the photoreceptor is rotated forward at the predetermined low rotational speed, and the surface of the photoreceptor is cleaned by the blade means, and then the photoreceptor is rotated forward at the predetermined high rotational speed. a pre-rotation means for applying a high voltage value suitable for the predetermined high rotational speed to the photoreceptor by the charging means; A copying apparatus comprising: a surface potential control means for controlling the surface potential on the photoconductor by controlling the output of the charging means based on the detection output of the detection means during the controlled rotation while controlling the rotation speed; It provides:

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an example of a copying machine to which the present invention can be applied, and its structure and operation will be explained.

The surface of the drum 1 is made of a three-layer seamless photoconductor using a CDS photoconductor, is rotatably supported on a shaft, and is rotated in the direction of the arrow by a main motor 21 activated when the copy key is turned on. Start.

When the drum 1 completes a predetermined rotation and potential control processing (preprocessing) described later, the original placed on the original platen glass 36 is illuminated by the illumination lamp 23 integrated with the first scanning mirror 24, The reflected light is reflected by the first scanning mirror 24 and the second scanning mirror 25.
is scanned. By moving the first scanning mirror 24 and the second scanning mirror 25 at a speed ratio of 1:1/2, the original is scanned while the optical path length in front of the lens 30 is always kept constant.

The above reflected light image shows the lens 30 and the third mirror 2.
6. After passing through the fourth mirror 27, an image is formed on the drum 1 at the exposure section.

The drum 1 includes a pre-exposure lamp 8 and a pre-neutralizing charger 2.
The charge is simultaneously removed by the charger 3, and then the charge is corona charged (for example, +) by the primary charger 3. Thereafter, the drum 1 is subjected to slit exposure with the image irradiated by the illumination lamp 23 at the exposure section.

At the same time, a secondary charger 4 performs AC or corona charge removal with a polarity opposite to that of the primary one (for example -), and then a high-contrast electrostatic latent image is formed on the drum 1 by uniform surface exposure using a full-surface exposure lamp 9. do. The electrostatic latent image on the photosensitive drum 1 is then developed by a developing roller of a developing device 7 and visualized as a toner image, and the toner image is transferred by a transfer charger 5.

Upper cassette 13 or lower cassette 14
The transfer paper inside is sent into the machine by a paper feed roller 11 or 12, and is sent in the direction of the photosensitive drum 1 by a register roller 15 with accurate timing.
The leading edge of the latent image and the leading edge of the paper can be aligned at the transfer section.

Next, while the transfer paper passes between the transfer charger 5 and the drum 1, the toner image on the drum 1 is transferred onto the transfer paper.

After the transfer is completed, the transfer paper is separated from the drum 1 by a separation belt, guided to a fixing roller 19 by a conveyor belt 17 via a paper detection sensor 16, and fixed by pressure and heat, and then transferred to a discharge roller 42.
The paper is discharged to the tray 34 via the paper detection sensor 18.

Further, 29 is a conveyance fan for reliably conveying the transfer paper. Further, after the fixing is completed, the fixing roller is cleaned by the web 20.

After the transfer, the drum 1 continues to rotate, and a cleaning device 6 consisting of a cleaning roller and an elastic blade cleans the surface of the drum 1. The recovered toner is collected in a discharge toner container 43 through a pipe 45, and the process proceeds to the next cycle. .

(Operation unit) FIG. 2 is a plan view of the operating section.

In the figure, 55 is a key for selecting the upper and lower cassettes, 54 is a slide lever for setting copy density, and position 5 is the standard density.
53 is a numerical key for setting the number of copies; 7
1 is a clear key for canceling the numerical value; 51 is an interrupt key for copying another number before the copying of the set number by key 53 is completed;
52 is a copy key for commanding the start of copying;
50 is a stop key for stopping the copy operation during continuous copying of the set number; 57, 58,
59 is a key for selecting the same size copy, enlarged copy, and reduced copy; 60 to 62 are indicators for displaying the selected reduction ratio; and 60 is a key for displaying the selected reduction copy mode. 61 displays the enlarged copy mode, and 62 displays the same size copy mode. There are five modes for enlargement: a mode for converting A size to B size, and a combination of reduction ratios of 1:0.67 and 1:0.79 and appropriate cassette selection. 72 displays the upper and lower stages of the cassette selected by the cassette selection key, and 56 displays the type of cassette loaded in the selected stage. Also, when the reduction key 59 is turned on, cassettes whose reduced size and sheet size match are displayed blinking when the selected cassette does not. At the same time, the size of the previously selected cassette is also statically displayed.

63 to 67 are warning indicators from the main body, all of which are displayed as pictograms. 63 is a paper feed check indicator that lights up when copy paper is jammed inside the machine. Reference numeral 64 lights up when there is no cassette in the cassette stand selected on the paper/cassette replenishment indicator, or when there is no paper left in the cassette set in that cassette stand. Reference numeral 65 denotes a discharged toner full indicator, which lights up when the container 43 is full of toner that has been used once and collected in the copying machine. Reference numeral 66 indicates a developer replenishment display, which lights up when the amount of developer in the developing device falls below a specified amount. Reference numeral 67 is a key counter confirmation indicator, which lights up when the key counter is not inserted into the socket of the main body.

70 is a weight indicator. This display lights up when the power switch is turned on and the temperature of the fixing heater is lower than the specified value, and when the temperature exceeds the specified value,
The light turns off when the wait UP process is completed.

Reference numeral 68 denotes a copy number display, and when the desired number of copies is set using the numeric keypad 53, the set number of copies is displayed in seven segments. It is possible to set 1 to 99 sheets at a time. Approximately 60 seconds have elapsed since the end of copying, or by pressing the clear key 71 or the interrupt key 51, the set number of sheets and number of copies will automatically return to 01. 68 is an interrupt indicator that lights up when the interrupt key is pressed and goes out after the interrupt key is pressed.

(Control Circuit) FIG. 3-1 is a control circuit diagram of the copying machine shown in _FIG . ,69,
Q 72 is a microcomputer (hereinafter referred to as a management computer) that controls display operations and the start of copying operations, etc. _Q101 is a microcomputer (hereinafter referred to as a sequence computer) that controls the drive of the main motor, high voltage transformer, etc. for executing the copying process. ). Q ₁₀₂ is a ROM memory that stores the programs shown in the flowcharts of Figures 6-1 to 6-4 in the form of command word code routines, process timing data for sequence control, the number of copy sets and copy counts by key 53, and key 57. 59, size data from the cassette sensor, count number at the time of interrupt emergency copying, cassette stage save data, etc., RAM memory, I port, O port and I/O port that control input and output.
The ROM program is read by the O port and the clock O of the clock generator 700, and the ROM,
CPU that processes I/O and processes programs
This is a one-chip microcomputer that has the following functions in one chip semiconductor. Q ₁₀₁ is also a one-chip microcomputer similar to Q ₁₀₂ , and the ROM memory stores programs shown in the flowcharts of FIGS. 7-1 to 7-6.

Q ₁₀₃ to _{Q 105} are ports for expanding the five I/O ports of each computer to 13 as shown in the figure. Reference numeral 800 corresponds to the circuit of each display of the operation unit and is connected to the O ₄ and O ₅ ports of the management computer, and 801 corresponds to the input circuit of each key and is connected to the i ₅ port. 802 is the above key matrix 8
01, a clock pulse generator for creating a probe signal (digit) to scan the display system 800, connected as an input to the program interrupt port of _Q102 . Divide this pulse to the port
Outputs a repeating signal from _O4 . Reference numeral 803 indicates two switches that detect the position of the lens system and operate according to lens movement.The combination of the two switches outputs a signal for 1x magnification at 30-1 in Fig. 1, and outputs a signal for 1x at 30-2 in Fig. 1. When the signal is enlarged, a signal for reduction is 0.79 when the signal is 30-3, and a signal for the signal is 0.67 when the signal is 30-4 is output to _Q105 . Reference numeral 804 indicates four switches in each of the upper and lower rows that are activated by the cams of the cassettes when the cassettes are turned on, for detecting the sizes of the cassettes 13 and 14. Outputs the eight types of size data shown. Reference numeral 806 denotes a switch 41 which operates when a sheet is manually inserted from above the lid of the upper cassette 13, and causes one copy of this sheet to be executed by sharing the roller 11 with the switch 41. The sequence for this corresponds to the hand pointing case in FIG. 4-2. 807 is a switch for detecting the absence of toner in the developing device 7; 808 is a switch for detecting the presence or absence of a key counter (total counter for each operator) and poor contact; the display is driven by a circuit not shown. Reference numeral 805 denotes a lens motor circuit for setting the previous lens system to a desired position in response to a magnification change input, etc., and is controlled in accordance with the selection key 59 position detection switch 803.

809 is a line for data exchange between the computers Q ₁₀₁ and Q ₁₀₂ , and arrows correspond to data requests and data directions. 810 is a clutch circuit for turning on the registration roller; 811 is a clutch circuit for inverting the mirror system to return after exposure; 812 is a developing device motor drive circuit; 814
815 is a high voltage transformer circuit such as a primary corona, and 815 is a switch installed at the mirror reversal position for the above reversal.
816 is a switch that generates a timing signal for register feeding; 817 is a home switch that is turned on when the mirror system is at the stop position; and 818 is a drum clock consisting of a photointerrupter that generates pulses by the rotation of a disk coaxial with the main motor. A pulse generator 819 is a main motor circuit for rotating the drum, to which the clutches described above and below are connected for power. Reference numeral 820 denotes a circuit for the lamp 10 which is controlled by the timing as shown in FIG. 4-2, and is turned on in a substantially opposite relationship to the exposure lamp 23. 821 is a clutch that moves the mirror system for exposure scanning; 822 is a circuit for the exposure lamp 23; 823 is a circuit that turns off the fixing heater when an abnormality is detected in the machine; 824 is a clutch that turns on the cassette roller 11 or 12;
25 is a circuit for increasing the key counter, and 826 is a circuit for detecting a jam in the sorter 46, which outputs a jam signal when a sheet presses the switch 47 provided at the entrance of the sorter in Fig. 1 for a longer time than specified. . 827 is a mechanical latch relay that is set when the main body or sorter is jammed, and the sequence computer _Q101 reads the status of this relay through the _i4 port of _Q104 . By releasing this relay, the copy blocking state is released, and the display of the number of jam losses on the display 68 is reset, and the number of losses is subtracted from the original number of copies and displayed.

This display 68 initially displays '01', displays the input number at key input, and when copying starts, displays the number subtracted by one from that number each time paper is fed. At the final scan reversal, the original input number is displayed again to facilitate re-copying the same number. After 60 seconds, it returns to '01' again.

During copying, abnormalities in the forward and reverse clutches (the mirror does not reach the specified position at the specified time even though control output is performed), abnormalities in the drum clock pulse generator 818 (pulse intervals are longer than specified), temperature of the fixing heater The control thermistor may cause problems such as disconnection.
When Q ₁₀₂ is detected, the number display 68 displays an error message 'E1'...'E3' to identify the trouble. By repairing that part, the original number before switching is displayed.

Also, when the sorter preparation OK signal cannot be obtained from the sorter 46, 'EO' is similarly displayed. This display reset is also the same as above.

Also, when a jam occurs, the sequence computer
Sheet sensor 16 input to _i5 port of Q ₁₀₁ ,
18 sends jam data to Q ₁₀₂ via 809. Q ₁₀₂ determines the number of jam losses as 1 for the former and 2 for the latter, and displays them on the display 68 as 'P1' and 'P2'. Similarly, 'P0' is displayed during sortage jam.

In this example, reduced copying can be performed regardless of the cassette size, but it is not completely unrelated to the size detector 804, and is limited to only when reducing or equal size is selected.
Only when the size is not appropriate, the display 56 blinks to indicate the appropriate size. The sheet size that is being copied in parallel is also displayed. This has made it extremely safe to handle. The enlarged copy always scans B4 size strokes in consideration of the use of partial enlargement, so it is not displayed, but it is also possible to display whether or not it is appropriate.

In addition, in this example, in the case of enlarged copying, the scan stroke corresponds to the B4 size, which is one size before the maximum cassette size, instead of the A3 size, but if the enlargement ratio is higher, the scan stroke corresponds to the n-th lower size from the maximum, such as A4 size. It can also be made to correspond to Furthermore, if the enlargement is performed in a plurality of modes, a lower size such as the n-th or n+1-th size may be selected. These can reduce wasteful scanning movements as much as possible and increase the speed of repeated copying of enlargements.

(Display Circuit) Next, the display circuit 800 will be explained using FIG. 3-2. This circuit is a circuit diagram corresponding to the operation section 501 shown in FIG.

This circuit is connected to the DC controller board equipped with the microcomputer Q102 shown in Figure 3-1, and the key scan probe signal
Digit1~6, key scan output signal KEY0~
3. Digit signal JD- for dynamic display
1, 2, 4, 5, 6 Furthermore, each terminal of dynamic display segment signals SEG-a to G is connected to Q10.
Connected to 2.

Furthermore, regarding the relationship with FIG. 2, the light emitting diode LED801 for displaying two-digit seven-segment numbers is as follows.
Light emitting diode corresponding to copy number display 68
LED802~LED808 and LED818,81
9 correspond to the cassette size display 56 in FIG. 2 with the same names. light emitting diode led
809 to LED815 are reduced in figure 2,
The same name corresponds to enlargement and same-size selection displays 60, 61, and 62. However, M in FIG. 3-2 represents enlargement, and 1:1 represents equal magnification. Further, the light emitting diodes LEDs 816 and 817 correspond to the upper and lower stages of the cassette upper and lower stage selection display 72, respectively. These display elements LED801 to LED819 are JD-1
As each digit signal from JD-6 to JD-6, a +24V power supply is sequentially applied in a pulsed manner in the illustrated combination, and as each segment signal from SEG-a to SEG-g, in the similarly illustrated combination,
OV power is selectively applied to dynamically light up.

(Control operation) Operation time charts in Figures 4-1 and 4-2,
The control operation will be explained with reference to the control flowcharts shown in Figs. 6-1 to 6-4 and Figs. 7-1 to 7-6.

As a cycle executed prior to the above-mentioned copy cycle, there is a step of increasing the temperature of the fixing device while keeping the drum 1 and the fixing device 19 stopped after turning on the power switch SW1. (Figure 4-1,
Power switch on flow 70, 7 in Figure 7-1
1) This is to prevent the toner from solidifying in the fixing device until the temperature of the fixing device rises to a certain level, which could damage the fixing roller 19, and to raise the temperature more efficiently. It is.

(Pre-rotation, control rotation, post-rotation) Next, when the temperature of the fixing roller 19 exceeds the first set temperature, the main motor 21 is rotated at a low speed, and at the same time, the entire surface exposure lamp 9, the pre-exposure lamp 8,
The blank exposure lamp 10 is turned on to start irradiating the drum surface, and while the drum 1 rotates once, high voltage is applied to the secondary charger 4 and the light irradiation rotation continues until the second set temperature is reached. Yes (steps 72, 73). As a result, if the temperature of the fuser exceeds the first set temperature, the toner is melted.
Since the fixing roller 19 is not damaged, the temperature distribution of the fixing unit is made uniform, the residual charge on the drum 1 is eliminated by the secondary charger 4, the light memory of the drum 1 is reduced by light irradiation rotation, and the drum surface is cleaned. 6
Clean by. In Figures 4-1 and 4-2, the dotted line in the main motor indicates low speed, and the solid line indicates high speed. It detects whether the rear door of the machine is opened or closed during a wait, turns off the wait lamp when it is opened, and waits for a copy start command to be input.

Further, until the temperature rises to the second set temperature, the lower fixing roller heater 32 is also turned on, contributing to the temperature rise.

Next, when the fixing roller reaches the second set temperature, the main motor 21 starts rotating at high speed and high voltage is applied to the pre-static eliminator 2, primary charger 3, secondary charger 4, and transfer charger 5 at high speed. A value suitable for the rotation is added and the drum rotates once. It is called forward rotation (74,7
5). This is to apply high pressure to the entire surface of the drum 1 after various high pressures have been applied. When switching the drum speed, Q101 turns off the low speed signal to the main motor and outputs a high speed signal after 30 msec (73-2, 73-3). This prevents switching shocks.

At the same time, if the position of the lens 30 is not at the position (30-1) for performing the same-size copy, the lens 30
Movement to the same magnification position is started (76).

Next, when the drum 1 completes one rotation, the drum surface potential (referred to as VSL) is measured by the potential sensor 44 with the blank exposure lamp turned on, and then, with the blank exposure lamp 10 turned off, the drum Measure the surface potential (referred to as VD). Based on the values of VSL and VD, the high voltage current flowing through the primary charger 3 and secondary charger 4 is controlled so that it approaches predetermined VD and VSL. This control is repeated several times (77).

Next, when the position of the lens 30 has reached the same magnification position (30-1 in Fig. 1), the original exposure lamp 23 is turned on, and the standard white plate 35 is illuminated with a reflectance corresponding to the white background of the original. , the potential on drum 1 (VL
) is measured by the potential sensor 44.
By measuring VL, the optimum image can be obtained at the "5" position of the density adjustment knob 54.
The lighting voltage of the original exposure lamp 23 is shifted.
This VL measurement control is repeated several times to optimally control the shift amount of the lighting voltage of the document exposure lamp 23. Finally, VL is measured and the developing bias of the developing device 7 is set to the optimum value.

As described above, by measuring VSL, VD, and VL (collectively referred to as potential control), the amount of charge on the high-voltage drum 1, the light amount of the exposure lamp 23, and the developing bias are controlled, and the optimal image is created. It is configured so that it can be done. Then, when the VL is measured and the control ends, the wait ends and copying becomes possible (78).

Further, as a cycle after the control rotation or after the copy rotation is completed, the drum 1 is rotated and the residual charge and memory on the drum are removed by the secondary charger 4,
There is a step of cleaning the drum surface (hereinafter referred to as post-rotation). This is about 1/5 rotation using only the secondary charger 4, and about 1/2 rotation with the voltage applied to the secondary charger 4 being weak. After the copy rotation is completed, the paper is rotated only by light irradiation until it is ejected.

The purpose of this post-rotation is to leave the drum 1 electrostatically and physically clean. After the post-rotation is completed, the drum stops and the fuser lower heater 3 is turned on again.
2 lights up, and the fixing roller is controlled by the thermistor 34 so that it is maintained at the third set temperature (steps 570 and 57 in Figure 7-5).
1).

After that, if it is left unused for 2 hours without doing anything, the main SW2 will automatically shut off.
It is turned off (572).

Before auto-shutting, when each key is operated, the management computer sets each data.

(Copy operation) The copy key is pressed and the data is transferred to sequence Q1.
If transferred to drum 1, depending on the time
The pre-processing before starting the copy operation described above changes depending on the stop time (leaving time) and variable magnification mode (573, 574).

The differences in this preprocessing are listed below.

(1) Leaving time 60 seconds or less If the variable magnification mode is changed, the developing bias must be changed by measuring VL.

If there is no change in magnification mode, there is no potential control.

(2) Standing time 60 seconds or more Control the optimum value of image formation by measuring VSL, VD, and VL.

After the above preprocessing is completed, the copying operation shown in FIGS. 7-1 B and C begins.

That is, even if a variable size copy is to be made, if the start time is 60 seconds to 2 hours, the drum is operated at high speed in advance and then switched to low speed. Thereby, the above-described preparation process for the drum can be carried out sufficiently in a short period of time.

When the same size data and copy start command are sent from the management computer Q102, the sequence computer Q101 judges this (via 78 and 79 when in B mode, and via 77 when in C mode), and make it faster. When changing magnification (reducing or enlarging), the drum is delayed by 30 msec to slow down (80). Next, as in step 81, the process is turned on and a lens movement permission signal is sent to the management controller Q102. Q102 receives this and sets the lens at a desired position according to the control operation shown in FIG. 6-4. In this way, since the lens is set only after copying is started, unnecessary lens operation due to zooming is avoided. Therefore, abnormal noise caused by lens movement can be reduced, and shocks can be prevented as much as possible. In this example, this is performed when an emergency copy is performed by interrupting copying, which will be described later, and also when returning to the original copy mode after the copy is completed.

Also, when changing the magnification, the drum is rotated one more time (83).
This is for break-in operation when switching from high speed to low speed, and for potential stabilization and cleaning.

Management Q102 sets the position of the lens during the previous rotation. Only when the lens is moved, the potential is measured and a predetermined developing bias is set. (1
71). Next, sequence Q101 to management Q102
requests variable magnification mode data, and when it determines that the data is an enlarged copy, sets in the RAM data such that the image is inverted at the middle position among the three positions as mirror system scanning inversion position data. (17
2,173). In other words, no matter what the cassette size is, the middle B4 size position is the stroke length.

In the first reduction mode (1:0.79), (17
3) Request size data of the selected cassette from the management Q102. Then, it is determined whether the cassette size is B5 (174), and if so, the short half-size position (A4) is set as reversal position data (175). If not, it is sequentially determined whether they are A4R, A4, B5R, or u2, and if they are all different, the longest full size position (A3) is set as inverted data (176). In either case, the original middle position is set. Note that u2 is a small cassette that can store various small-sized sheets such as postcards.

When in the second reduction mode (1:67) (177),
If it is not A4, B5, U2, or B5R, the full size will be used as the reversed data, and in any case, the middle position will be used.

At the same size, only A3 is full size, A4, A5,
Half size for any u2, medium size for others.

In this way, an appropriate reversal position can be determined depending on the magnification mode and the cassette at that time. This can prevent unnecessary scanning operations.

Next, in Figure 7-3, the number of sheets remaining in the machine counter, total counter, and key counter are incremented by 1 (271), it is determined whether the manual feed switch is on, and the operation control of the upper cassette roller is performed. Do it (272). The stage data of the selected cassette from the management Q102 is determined and one of the rollers 11 and 12 is turned on (273). After that, turn off the solenoid that increases the key counter by 1. After a delay due to the count of the drum clock, a developing bias voltage is applied to the developing device, the blank lamp is turned off, and the document exposure lamp is turned on (274).
Check the home position of the scanning optical system (275),
It outputs its advance start signal (276).

At this time, one of the four advance clutches provided according to the variable magnification mode is selected, and the mirror and lamp are advanced at a scanning speed determined by the peripheral speed of the drum and the variable magnification ratio. 270mm/sec for actual magnification, 240mm/sec for 1:0.79 reduction, 284mm/sec for 1:0.67
seconds, 148mm/second when expanded. Outputs a signal to turn on the registration roller 15 during advancement (7-4
371) in the figure, it is determined whether or not the previously set inversion position has been reached by comparing it with the switch signal 815 in FIG. 3-1 (372). Then, the blank lamp is turned on, the forward motion of the mirror system is turned off, and the reverse clutch is turned on (373). Then, the lamp is turned off or the exposure lamp is turned off with a delay only during reduction copying. The optical system reaches the home position and stops (470).

Then, each process is turned off and the aforementioned post-rotation routine is entered (570). Next, the discharge of the transfer paper from the switch 18 is confirmed and the drum is stopped (571). Thereafter, the above-mentioned routine processing is performed depending on whether the input timing of command data for restarting copying is within 60 seconds or other than that. If left unattended for more than 2 hours, the power of the microcomputer remains and everything else turns off.

Fig. 7-6 is inserted into the closed loop of Figs. 7-1 to 7-5, and the computer Q10
1 and Q102, control to detect sheet discharge from the sensor 18 and decrement the in-machine counter by 1, control to input and judge a thermistor disconnection signal and send abnormal data to the management Q102 (I/O),
Further, a timer is used to determine troubles in the forward and reverse clutches, and a timer is used to determine troubles in the drum clock pulse generator, and data transmission is similarly controlled. If a problem occurs, the process returns to the power switch determination routine shown in Figure 7-1 and waits.

The management Q102 receives this data and displays identification such as E1, E2, etc. on the numerical display 68.

(Drum Speed Switching) The main motor M1 is a motor that mainly drives the rotation of the photosensitive drum, fixing roller, etc. In this embodiment, the rotation direction of the motor is controlled so that the rotation speed of the drum is controlled in two stages. In the power transmission block diagram shown in Figure 5-1, one-way clutches CL1 and CL2 are provided on the output shaft of motor M1, and CL
2 is provided with a reduction gear. When the motor rotates clockwise (normal rotation), the power is directly outputted as clockwise rotational power via the one-way clutch CL1, that is, as shaft rotation along the normal rotation power transmission route LT1. Next, when the output shaft of motor M1 is rotated counterclockwise (reversely), at this time CL1
does not transmit power, and conversely, CL2 transmits power while the power is reversed, and is decelerated to a predetermined rotation speed by gear G1, and the output from G1 is again clockwise rotation, that is, the power at the time of reverse rotation. Along the transmission route LT2, the rotation is decelerated and output on the same axis as the above-mentioned axis.

In this way, in this embodiment, the rotational speed is changed by switching the rotation of the motor M1 between forward and reverse directions. Thereby, the rotational speed (copying process speed) of the photosensitive drum can be changed at low cost and by simple control, and stable rotation can be obtained.

FIG. 5-2 shows another embodiment of speed switching. The motor 1-1 is a motor that has two outputs in the same rotational direction but different only in rotational speed, and the transmission of each motor is switched using electromagnetic clutches CL3 and CL4.There are several ways to simply switch the rotational speed, but these are If the method described above is limited to two-speed switching, it is the cheapest and has the highest reliability.

In FIG. 3-3, in order to control speed switching mainly aimed at copying process speed, the common terminal J11-1 of the main motor M1 is connected to one power source, and the main coil terminal J11-2 and the auxiliary coil terminal J11- 3, and connect the terminals J11-2 and J11-3 to the other power supply via solid state relays Q304 and Q305, and turn on Q304 to turn on the M
1 is rotated in the forward direction, and Q305 is turned on to control M1 to be rotated in the reverse direction.

According to the switching timing of this drum speed, high voltage transformers for primary and secondary charging, transfer,
If the pre-static elimination transformer is on, its output is switched at a ratio of 1:0.7. The drum speed also has a 1:0.7 relationship. Experiments have shown that an output ratio approximately corresponding to the drum speed ratio is sufficient. Since the output of the processing means is weakened at low speeds, processing can be performed with an appropriate potential and a stable image can be obtained regardless of the variable magnification mode. The amount of light from the exposure lamp 23 is also changed in accordance with the movement of the lens due to the variable magnification set so as to always provide the same amount of image irradiation. In other words, it indirectly depends on the circumferential speed of the drum.

Incidentally, the voltage applied to the lamp can also be controlled in accordance with the drum circumferential speed switching control.

Further, in this example, the drum rotates at a low speed until the variable size (reduction, enlargement) copying is completed and the drum stops. Thereafter, during rotation, the same size key is input, and the management Q102 receives it and displays it, and even if the copy key is used to start, the drum does not speed up. After that, the main motor's reverse rotation output is turned off only after rotation is complete, and the output is switched to forward rotation after 30 m seconds. Therefore, unevenness due to speed switching does not occur in equalizing the drum potential during post-rotation.

Further, the rotational speed switching system of this example can correct rotational changes due to differences in power supply frequency by detecting the change or automatically or manually switching the motor between forward and reverse directions depending on the frequency.

(Key input/display control) The operation of the management controller Q102 will be explained with reference to FIGS. 6-1 to 6-4. In Figure 6-1, when the computer power is applied, the I/O ports and RAM are cleared to the initial state (step 6).
0) Confirm that the reset of the sequence controller Q101 has been completed (61), and start operation. Then, an oscillator signal (1.2KHz) is applied to the interrupt terminal (iNT) to enable program interrupt processing (62), and this signal generates an interrupt, and the routine shown in Figure 6-2 Execute the input scan of each KEY and the dynamic display of each display (1
62) and Q101 are monitored.

Incidentally, since the probe signal for this dynamic display is used to detect an abnormality in the management controller Q102, it is scanned and outputted regardless of whether the main switch is turned on or not, in preparation for display. However, when the main switch is not turned on, the display power is turned off by the sequence controller Q101, so it does not actually light up.

By the way, when the main SW input signal is transmitted from the sequence controller Q101 by serial transfer, the management controller Q102
Key input is permitted, the 2-hour timer is cleared, and restarted (63-65).

During wait, sequence controller Q10
1, the lens position must be at the same magnification position in order to control the current of the charger and the document exposure lamp by potential control. Therefore, the management controller Q102 is the sequence controller Q1
Since a signal requesting the "lens equal magnification position" is sent from 01, the lens is made equal to the same magnification by the lens movement subroutine shown in FIG. 6-4 (67).

When the wait end signal is transmitted from the sequence controller by serial transfer, the 60 second timer is cleared and restarted (68).

By the way, the 2-hour timer and the 60-second timer are timers that are extended each time the operator operates the copying machine, such as by pressing a key. The 2-hour timer turns off the power switch to save energy when the operator forgets to turn off the copier when the copier is not operated for more than 2 hours.
Make it. Further, the 60 second timer is used to initialize the display when the operator does not operate the copying machine for 60 seconds or more. This 60 second timer selects the standard mode, that is, the same size selection and the lower cassette, and sets the set number of copies (display 68) to "1" (69). However, if there is not enough developer or if there is no paper or cassette, the 60 second timer will not work. This is done in consideration of the fact that the operator is recovering from a copy interruption state. Also, the 60 second timer does not operate while waiting.

When hand-held mode data is sent from sequence Q ₁₀₁ , the display 68 is switched to 1 (70). Start data is not sent to sequence Q ₁₀₁ even if the copy key is turned on while the detection signals of no toner, no cassette, and no key counter are input (7
1). During this time, the operations shown in FIGS. 6-2 and 6-3 are executed, so it is possible to change the inputs of the number keys, magnification keys, and cassette keys, and to change their display.

However, after the copy key is turned on, changing the magnification mode by operating the magnification key is prohibited (72). The 2 hour and 60 second timers are also prohibited from running. Next, in accordance with the equal magnification request for drum potential control from sequence _Q101 , the process shown in FIG. 6-4 is executed to set the lens at a predetermined position (FIG. 1 3-1 to 3-4) (74). Until then, cassette key 55, number key 5
It is possible to change the number of cassette stages and copy sets by the operator in step 3, but it will be prohibited from now on (operator 7
5). As a result, changes other than changes made by moving a movable part are allowed as much as possible even after the start of copying, thereby preventing wasted copying.

The copy counter (display 86) is set to -1 every time data is received from sequence Q ₁₀₁ when the optical system is inverted.
Then, it is determined whether or not the number has reached 0 (76), and when it is 0, the display 86 is returned to the initial set number and the key input is performed (77). Also starts the auto clear timer. After the reversal, the key counter is removed, there is no paper in the cassette, it is determined whether the cassette is absent (78), and the input of the stop key 50 and interrupt key 51 is determined (79). If any one of them occurs, the sequence shifts to the same mode as copy completion. However, the display remains unchanged except for the stop key and key counter, and copying is interrupted.

Upon completion, send copy completion data to sequence Q ₁₀₁ . This is determined in step 374 of FIG. 7-4 and the process is repeated or the process proceeds to the above-mentioned post-rotation.

When the above paper out, counter off, stop key, interrupt key is turned on, etc. during execution of the copying operation, the circuit holds that state and determines the state as an input after detecting the above reversal position. At that time, a display to that effect is displayed and the display on the numerical display 86 is switched. Therefore, in the case of a stop key or an interrupt key, a change in the display of this number is used as a guide for replacing the document. When the key counter is removed or the stop key is turned on, the display returns to the initial set number.

(Cassette Size Display) The relationship between magnification selection and cassette display will be explained with reference to FIG. 6-3. This is after key input permission
SUBPAPER (66) is executed by step 73 at the time of copy start. First, a display 56 of the size of the cassette loaded in the cassette selected by the upper/lower cassette tier selection key 55 and a display 72 of the selected tier are displayed. That is, it is determined whether or not it is in the upper stage (261), and when it is in the upper stage, the switch 804 that senses the size of the upper stage is input to first determine the presence or absence of paper and the presence or absence of a cassette. When empty, cassette size is not displayed. Then, the culture change input is determined and the display described below is displayed. If yes, the cassette size and tier of that tier are displayed. (263). When there is no display, a step display is displayed, and a warning lamp 64 is lit by a circuit not shown. The same applies to the case where the lower input is determined.
In the case of hand-holding, the hand-holding data from sequence Q ₁₀₁ does not display the cassette, but displays a variable magnification display.

By the way, when performing a same-size copy (267), the inappropriate cassettes are A4R (a reduction cassette with a different sort orientation from the A4 cassette) and B5R (a reduction cassette with the same relationship as the B5 cassette). be. However, A4R or B5R is selected by the cassette selection key 55.
is loaded, the loaded cassette is lit without blinking, and the cassette sizes other than A4R and B5R are blinked (268). If an appropriate cassette (other than A4R or B5R) is loaded, the display will only display the loaded cassette and will not flash. Also, copying operations are not prohibited even if the display is blinking. This allows you to copy to sheets in any orientation.

Next, when reduction from A3 to B4 is selected using the reduction selection key 59 (264), the appropriate cassette is
If the cassette is a B4 cassette and no appropriate cassette is loaded, as in the case of the original size, the loaded cassette is displayed and the appropriate cassette is flashed in parallel (265). Also, if the loaded cassette is appropriate, only the appropriate cassette B4 is displayed, just like the original size. Similarly, when A3 → A4 is selected, the appropriate cassette is A4R, when A4 → B5, B5, when B4 → B5, B5R, and when B4 → A4, the appropriate cassette is A4R.
All cassettes are suitable for A4R and enlargement.

(interrupt copy) Also, the interrupt operation will be explained.

By pressing the interrupt key 51 during continuous copying (or during standby), continuous copying is interrupted and interrupt copying becomes possible. That is, step 79 (6-1
When the input of the interrupt key 51 is determined according to the figure),
The number of copies completed up to that point, the cassette stage signal, and the variable magnification mode signal are stored in a predetermined area of the RAM memory. Then, the interrupt display lamp 69 is turned on.
When scanning of the currently fed document is completed, the copy number display 68 becomes "1" and copying stops. At this time, the display operations of the cassette upper/lower selection display 72, the size display (including blinking), the reduction selection display 60, the enlargement selection display 61, and the same size selection display 62 do not change. This is to reduce the need for the user to press other keys as much as possible, since most people turn on several keys to set an interrupt, so the current status is maintained.

However, if the interrupt copy is in a different mode than the one currently being performed, for example from reduction to enlargement,
Conversely, when you press the variable size selection key, such as from the first reduction to the second reduction, or when you turn on the cassette selection key 55, such as from A3 to A4, or from 10 copies to 5 copies.
It is possible to change the size and cassette by pressing the numeric keypad, such as copying sheets. However, if you leave it without doing anything, the timer will auto-clear and auto-set for 60 seconds or 2 hours (81).

Even if the display is changed, each display automatically returns to the state before the interrupt copy when the optical system scan of the last sheet of the interrupt copy is completed and the display is reversed. That is, it is determined that the copying for the set number of priority interrupt copies has been completed, the original number of copies is returned from the RAM memory area to the counter, and the original cassette stage and original scaling mode are returned.

Therefore, even if the interrupted user changes the magnification mode cassette upper and lower stages or the number of copies, the interrupted user can continue copying only by pressing the copy key after the interrupted copying is completed.

Further, at the time of interruption and restart, the work of moving the lens to set the variable magnification is performed after copying is started. Similarly, if the interrupt key 51 is turned on before starting the first copy or after setting each data such as numbers, the data will be stored in the RAM, new data can be input, and the data will be copied first. After the copy is completed, the original data can be copied using only the start key.

Stop key 5 after interrupt input and during interrupt copy
When 0 is turned on, the interrupt is canceled and the original copy interruption state is returned to, and the number of memories, size, etc. are displayed.

[Effects] As described above, according to the present invention, the rotational speed of the photoreceptor is set at a low speed at the beginning of the forward rotation after the power is turned on, so that the surface of the photoreceptor can be protected from wear caused by, for example, a blade. Furthermore, in the second half of the pre-rotation, the photoconductor is rotated at high speed at the same rotation speed, and the charging means applies a high voltage value suitable for the rotation speed at the same magnification, so it is charged before the actual surface potential control. Not only can the output of the means be stabilized, but also the surface condition of the photoreceptor can be stabilized at the same magnification. As a result, surface potential control can be accurately executed at the same magnification, which is frequently used, and high-quality copying can be performed. Furthermore, according to the present invention, the low-speed rotation during magnification change is also applied to the low-speed rotation during the pre-rotation, so there is no need to provide a special low-speed rotation during the pre-rotation, and the device configuration can be further simplified.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a copying apparatus to which the present invention can be applied, FIG. 2 is a plan view of the copying apparatus shown in FIG.
Figures 1, 3-2, and 3-3 are control circuit diagrams of the copying machine in Figure 1, Figures 4-1 and 4-2 are input/output operation time charts, and Figures 5-1 and 5. Figure-2 is the main motor drive block diagram, Figures 6-1 to 6-3.
The figure is a control flowchart by the management computer, and Figures 7-1 to 7-6 are control flowcharts by the sequence computer.
0-1 is a lens at the same-magnification copying position, 1 is a photosensitive drum, 23 is an exposure lamp that scans, and 2
4 and 25 are mirror systems that scan, 13 is an upper paper feed cassette, 14 is a lower paper feed cassette, and 46
is a sorter.

Claims (1)

[Scope of Claims] 1. A scanning device that exposes and scans a document image; and a charging device that corona charges a photoreceptor; the document image exposed and scanned by the scanning device is formed as a toner image on the photoreceptor; various process means for transferring to a transfer material; a blade means for removing toner on the photoreceptor and cleaning the surface of the photoreceptor; a detection means for detecting the surface potential on the photoreceptor; and a variable magnification ratio. an input means for making a selection; and a control means for controlling the operation of the scanning means and the photoreceptor to perform a desired variable magnification copying operation based on the variable magnification inputted from the input means, the control means a scanning speed changing means for changing the scanning speed of the scanning means based on the magnification inputted from the inputting means; and a rotational speed of the photoreceptor when the magnification inputted from the inputting means is equal to the same magnification. a rotational speed changing means for setting the rotational speed of the photoconductor to a predetermined high rotational speed, and setting the rotational speed of the photoreceptor to a predetermined low rotational speed when a specific magnification ratio other than equal magnification is input from the input means; After turning on the power, the photoreceptor is rotated forward at the predetermined low rotation speed, the surface of the photoreceptor is cleaned by the blade means, and then the photoreceptor is rotated forward at the predetermined high rotation speed. a pre-rotation means for applying a high voltage value suitable for the predetermined high rotational speed to the photoreceptor by the charging means; surface potential control means for controlling the surface potential on the photoreceptor by controlling the output of the charging means based on the detection output of the detection means during the controlled rotation, and controlling the surface potential on the photoreceptor. A copying device characterized by: