JPH0477310B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an image forming apparatus such as a copying machine having a function of detecting trouble inside the machine. Conventional copying machines have a function to detect jams caused by paper jams, etc., and once a jam occurs, the copying operation is stopped until the cause of the jam is removed. Normally, when a jam occurs, the operator removes the cause of the jam and then presses a reset button provided in the apparatus to restart the copying operation to clear the jam. However, when a jam occurs at multiple locations within the device at the same time, the operator sometimes presses a reset button to clear the jam by simply removing the cause at one location without noticing it. As a result, the copying operation has to be restarted in the jammed state, causing further trouble within the apparatus and eventually causing damage to the apparatus. 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 that can perform diagnostic operations with high accuracy and improve the reliability of the apparatus. That is, the present invention includes: a conveying means for conveying a recording sheet; an image forming means for forming an image on the recording sheet conveyed by the conveying means; a power switch operated to supply power to the image forming means; a plurality of detection means provided at a plurality of positions on a recording sheet conveyance path to detect the presence or absence of a recording sheet for jam detection; controlling the conveyance means and the image forming means to perform an image forming operation; During image forming operation,
A control means having a program that detects a jam in the recording sheet based on the output of each of the plurality of detection means at a predetermined timing, and stops the operation of the conveying means and the image forming means when a jam is detected. and a power supply means for supplying power to the control means to maintain the power supply to the control means even after a jam is detected on the recording sheet, and a reset means for releasing the jam state in response to a predetermined operation. and the control means, in response to the ON operation of the power switch, and in response to the jam release operation by the reset means after detecting a jam in the recording sheet, and before starting the image forming operation. , the detection state of each of the plurality of detection means is determined in order, and if any of the detection means detects a recording sheet, the start of the image forming operation is prohibited and it is determined that the recording sheet remains. display,
An object of the present invention is to provide an image forming apparatus that can start image formation when none of the plurality of detection means detects a recording sheet. As a result, in an image forming apparatus controlled by a microcomputer, it is possible to check whether a sheet remains in the sheet conveyance path not only after the power switch is turned on but also after the jam release operation. Further troubles can be prevented from occurring, and the operability and reliability of the device can be improved. Furthermore, after a jam has occurred, the operator does not have to turn off the power switch and then turn on the power switch after clearing the jam.In other words, by simply clearing the jam, the operator can check for remaining sheets. This improves operability. Further, since the operator can see from the display the reason why image formation cannot be resumed, that is, the recording sheet remains in the machine, subsequent processing can be carried out smoothly, and operability can be improved. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an example of a copying machine to which the present invention is applicable. This is a copying machine that is equipped with a separate sorter outlet so that it can use a reduction mechanism and a sorter, and for high-speed, large-volume copying, the amount of paper that can be stored in the paper feed section is 50% smaller than that of a normal copying machine. It had a deck about twice as large as a conventional one, and also had a regular cassette, making it possible to feed paper mainly from the former. In addition, when copying a specified number of copies for each original,
In order to eliminate the trouble of distributing copies into predetermined numbers after copying, a so-called sorter is used in a copying machine, which automatically performs the distributing work. A variable magnification mechanism is also used to reduce the original image in three stages to obtain a duplicate image. In the figure, 1 is a photosensitive screen (for example, detailed in Published Patent No. 19455 published in 1975), 2 is a primary corona charger, 3 is a secondary corona charger, 4 is a lamp, 5 is a manuscript table, and 6 is a modulator. Corona charger, 7 is an insulated drum, 8 is a developer, 9 is a roller that feeds the transfer paper 10, 11 is a transfer charger, 12 is a conveyor belt, 13
is a fixing roller, 14 is a tray, 18 is a sorter, 2
0 is 10 pins. The document on the document table 5 is subjected to slit exposure while moving the lamp 4 and mirror 15, and is simultaneously exposed to the rotating three-layer screen 1, which has been previously charged by the primary charger 2, and statically exposed. Forms an electrolatent image. The primary latent image is used to form a secondary electrostatic latent image on the surface of the insulating drum 7 by the modulation charger 6, and the secondary image is developed with toner by the developer 8. The toner image is transferred to transfer paper 10 fed from the cassette 52 or lift deck 53 by the charger 11, the paper 10 is conveyed, the toner image is fixed by the heat roller fixing device 13, and the toner image is transferred to the sorter 18.
Alternatively, it is discharged onto the tray 14. Even after the secondary latent image is formed, the primary latent image does not disappear, so the screen 1 is further rotated and the charger 6 continuously forms the secondary latent image, and the transfer paper is sent one after another to the transfer section, where it is transferred and fixed. , the discharge continues a set number of times.
When the number of repeated secondary latent images formed by one primary latent image is exceeded, the primary latent image is formed again. In addition, 16 is a lamp for removing static electricity from the screen, 17
-1 is a cleaning unit for removing toner from the insulating drum 7, and 17-2 is an AC corona discharger for removing residual charges from the insulating drum 7. FIG. 2 shows the operating section and display panel of the apparatus shown in FIG. SW in the figure is the process load of the copying machine, the main switch for turning on the power to the control circuit, 21
is the copy start key, 22 is the copy number setting key,
23-1 is a set number display, and 23-2 is a copy completion number display, each digit being displayed by a 7-segment LED. 24 is a tray, 25 is a sorter selection key, and the key itself lights up when the key is turned on to indicate whether the storage section is a sorter or a tray; 2
Reference numerals 6 and 27 indicate a cassette selection key and a deck selection key, which lights up to display selection when the key is turned on, and also displays the size of paper in the cassette and deck through 32. 28-1 to 28-3
is a key for selecting the light and shade, and it sets dark, medium, and light, and when the key is turned on, it lights up to indicate that. Reference numeral 29 is a stop key for interrupting the copying operation, and 30-1 to 30-3 are keys for specifying magnification, each of which is set to 1x, 0.76x, and 0.65x, and the corresponding location on the display 31 is lit. When a tray is selected, the belt 19 in FIG. 1 moves as shown by the dotted line so that the paper is ejected from the first ejection roller 50. When the sorter 18 is selected, the belt 19 is set so that the paper is discharged from the second discharge roller 51 as shown by the solid line. The deck 53 can store 2,000 to 3,000 sheets of paper, and the cassette 52 can store 500 to 1,000 sheets of paper. The paper sent to the sorter 18 is carried by a constantly rotating belt 55 and sent to a bin. Guide pawls a to i are provided for each bin, and each time the detector D detects paper, the guide pawls are operated in order to direct the paper toward the bin and store it in each bin. That is, the solenoid SL2 is actuated by the key 25 to set the discharge port on the sorter 18 side as shown by the solid line, but if the copy key 21 is not turned on for a predetermined period of time (30 seconds) after this setting or if some key is not turned on, the automatic SL2 is then deactivated to return the discharge port to the tray 14 side. Also power switch SW
When turned on, the ejection port is set on the tray 14 in the same way when the ejection port is set to the sorter side and left for 30 seconds after copying is completed. Therefore, normal copying operations can be performed quickly without worrying about the ejection port. When one of the keys 28-1 to 28-3 is turned on, the amount of current supplied to the exposure lamp 4 is set to an amount corresponding to the specified density. But then I changed the copy key 21 to 30
If it is not turned on within seconds or if some key is not turned on, it automatically returns to the same light intensity as set with key 28-2. When the key 26 is turned on, only the paper feed roller 9 on the cassette 52 side is set to be operable.
27 is turned on, the roller 9 on the deck 53 side is set to be operable. However, if this roller is left alone for 30 seconds, it returns to the paper feed roller set of the deck 53 that stores A4 size paper, which is frequently used. When the magnification keys 30-1 to 30-3 are turned on, the position indicated by the lens and the mirror 15 provided in the optical axis of the image reflected by the lamp 4 are moved left and right using a motor and a solenoid in order to obtain a predetermined magnification image. and set it in place. But this also then 30
If it is left unattended for a second, it returns to the same magnification position as specified by pressing the key 30-1. Also, after repeatedly pressing the key 22 and setting the number of copies, the process returns to one copy in the same manner. After setting various condition modes in this way, the standard mode is returned to when 30 seconds have elapsed since the last setting operation. FIG. 3 shows a control circuit constituting an embodiment using a microcomputer. The ROM in the figure is a read-only memory in which the sequence contents of the display operation of key input data, the standard mode set operation, and the copying process operation are ordered in advance and stored in each address, and the contents can be retrieved each time an address is set. So, we use μPD454 manufactured by Nichidensha. RAM is a read/write memory that stores the number of copies and temporary control signals during process control, and is a memory that stores one set of binary codes. This is made up of multiple sets, and an arbitrary set is selected by an address designation signal, and data is written to or read from multiple flip-flops within the set using the company's μPD462. In the figure, addresses of memories and their areas are shown, for example, in the X'043' format. The last 1 digit number indicates the column, the 2 digit number indicates the row, and the 3 digit number indicates the memory chip. Here, X'043' is an area for storing data on variable magnification, and this data contributes to designation of lens magnification and display operation of the display 31. or
X'033' is an area for storing data specified by the magnification key, and the binary data of X'033' and X'043' is 0000 when the image is the same size, and 1000 when it is 0.7 times the image.
X′062′ is when there is no paper in the specified paper source.
This is an area that stores 1000. Table 1 shall be followed for each data area below. Also, the numerical data to be displayed on the segment displays 23-1 and 23-2 is
It is stored in the SET and COPY areas, and key-input data is temporarily stored in X'018' and X'01C'.
WA(0) is a three-digit working register used to run a timer that contributes to returning to standard mode, and WA(a) to WA(7) are registers that contribute to storing other temporary data. Table 2 shows the relationship between key input and stored data.

[Table] When there is no KEY input, F or 0000 is stored. I/O 100 to I/O 700 are input/output devices that generate data input signals such as paper out, keys, etc., and signals for driving solenoids and the like. I/O and its peripheral circuits are shown in Figures 4-1 and 4-5. I/O100~
600 is a well-known circuit including a latch circuit and a gate circuit, and here a μPD752 is used. In the I/O 100 in Figure 4-1, the output port O is connected via a DC driver to the drive circuit of a motor _M1 that rotates the screen drum insulating drum, and is connected to a high voltage transformer for each corona discharge. . Input port A connects the clock pulse CLK from the disk, which is the basis of the timing operation of the transformer and clutch, through a line receiver (input interface). Also, a switch linked to the main switch SW is connected to input port C.
Connects the SW as an input and contributes to determining the on/off state of the SW. Further, port D is connected to a circuit of a thermistor _Th1 that detects the temperature of the fixing heater, and contributes to determining the wait time up. In the I/O 200 in Figure 4-2, O ₀ , O ₂
is for each variable magnification motor _M3 , outlet switching motor _M2 ,
Connected through an input circuit similar to _M1 . _O1 , _O3
is connected to each magnification solenoid SL ₁ and output solenoid SL ₂ via the same input circuit as CL ₁ , and I ₁
~ I ₃ is the Hall element HIC installed in the lens system path.
It is connected to RD ₁ , RD ₆ , RD ₇ (eg, 0.6, 0.7 times) like the input B port and contributes to setting the magnification. In the I/O 300 in Figure 4-3, I ₀ and I ₁ are Hall elements TP and SP (tray, sorter) of the HIC installed at the exit to determine whether the output is a tray or a sorter.
are connected as described above to contribute to the outlet set.
O ₀ ~ O ₃ are lamps L ₁ ~ L ₃ (medium,
L0.6, L0.7, L1.0 (0.6
(x, 0.7x, 1x). In I/O 400 in Figure 4-4, O ₀ to _{O 3}
are the lamps L _S , L _T , for indicating the paper feed slot and exit.
Connected to L _D , L _P , L _C (each sorter, tray, deck, paperless, cassette). _I0 is connected to a switch that detects insertion of a key counter that counts the total number of copies. _I1 is connected to a well-known optical sensor that detects whether a cassette or deck is out of paper. Figure 4-5 shows the KEY&DISPIAYI/O port 70 for receiving input signals from each key into the computer and driving the segment display.
It is 0. In the figure, MAT is a well-known matrix circuit whose intersections are energized when the key is turned on, T ₀ to _{T 5} are digit selections of the displays 23-1 and 23-2, and time-division scan signals for scanning the matrix circuit.
KR ₀ to KR ₃ are ports for inputting matrix signals caused by key-on, and 100 to 106 and 107 are transistor driver circuits as shown in the figure. In MAT, "0", "1"..."9" are numerical keys, CL is clear key, COPY is copy start key, 1.0, 0.6, 0.7 is magnification key, dark, medium, light are light and dark keys, DEC , CAS, SP, and TP are deck, cassette, sorter, and tray specification keys. This device is a well-known device having a buffer register for key entry, a shift register for storing display data, a digit signal generator for displaying display data in a time-division manner, etc., and a μPD757 is used here. The CPU includes the above memory, one or more registers AC and PC for specifying addresses of input/output devices, one or more registers A, B, C, and D for primary storage, overflow bit OVF, and block CFT data signal lines. Control unit CT with addition/subtraction logic control to decipher input data and process data, arithmetic circuit
ALU, such arithmetic circuit ALU data decimal correction,
Has addition and exclusive OR functions. Note that the contents of register A can be rotated to the right (shifted to the right) or rotated to the left (shifted to the left). The CPU has the above circuits and is connected to the above external circuits through a plurality of lines. Briefly, the CPU first specifies the address of the ROM where the sequence is programmed, and then sends the contents of the specified address through the data signal line DB1.
It is read into the CPU, the CPU decodes it, and according to the decoded contents, it processes the data within the CPU itself when it is in chronological order from power-on.
Sometimes the data in the CPU is stored in a specified address in RAM, the data in a specified address in RAM is input into the CPU, and sometimes the data in the CPU is transferred to the output section I/O. -1~I/
Sequence control is performed by outputting to the signal line DB3 of O-4 and inputting the contents on the signal line DB3 of the input/output section into the CPU. The data shown in FIG. 5 are encoded in this order and stored in the memory ROM shown in FIG. This is a flowchart showing the control program. When the sub power switch installed inside the main unit is turned on, the control unit including the CPU is powered on, the ROM program is leaked, and processing begins (STAT). In step 1, RAM4bit, 256 words, address X'000'~
Clear all data of X′OFF′. Then, it is determined whether the switch SW is on or not, and if it is on, step 2 is executed. This determination is to check whether the input port _I2 of the I/O port 100 (Fig. 4-5) is 1.The CPU specifies the chip 100, takes the 4-bit input data into the accumulator ACC, and shifts it to the left. The process is repeated to determine whether 1 is set in the first bit. In step 2, necessary data is first written into a predetermined location in the RAM in order to set the image forming conditions to the standard mode. The data contents are shown in Table 1.

【table】

【table】

[Table] In standard mode, the reduction is 1x, the exit is the tray, and the copy density is medium, so the RAM data is (X'043') is a number other than 0, (X'033') is 0,
(X′053′) is 0, (X′042′) is 2, (X′032′) is 2
It becomes a number other than Note that (X'043') is the data at address X'043'. Regarding step 3, the number of sheets of paper collected in the deck is four times that of the cassette (approximately 2000 sheets). Therefore, frequently used paper (for example, A4 size) is collected on a deck and normally fed from the deck. Here, first,
To select the deck as the standard mode, check whether there is paper on the deck. Sense the I/O 400 and check the paper detector 61. If there is paper, set the data on the deck in RAM, that is, set (X'052') to 8 (3-1). When there is no paper in the deck, select the cassette, check the paper detector 60 to see if there is paper in the cassette, and if there is no paper, the paper out lamp 33
To light up, set (X'062') to 8. If there is paper in the cassette, set it to 0 (3-3). If there is paper in the cassette, set X'052' to 0 to specify the cassette (3-3).
2). In step 4, in order to display the copy setting counter 23-1 as 1 and the copy number counter 23-2 as 0, the hundredth place (X'03A') of the counter SET in RAM is set to 0, and the tenth place (X'03B') is set to 0. 0, first place (X'03C') is 1, hundredth place (X'04A') of counter COPY is 0, tenth place (X'04B') is 0, first place (X'04C') is 0. Set to . In step 5, the RAM is
The data set in 4 bits are simultaneously output to the I/O port. Display data (X'022') is the result of adding (X'032') + (X'052') + (X'062') and output to I/O 400. This results in a paperless lamp. , deck, and cassette selection indicator lights. In standard mode it is 6 or O ₀
~ _O3 outputs 0110 and the deck indicator lamp and tray indicator lamp light up. (X′023′) is (X′033′)
+(X′053′) and the content is (X′023′)
By outputting to the I/O port of X'300', the equal-magnification lamp and medium-density lamp are turned on. Furthermore,
The RAM contents of X'02A' to X'02C' and X'03A' to X'03C' are output to Key & Display I/OX'700' address, and 001, Display 000. In step 6, the Key & I/O device
The key input at address X'700' is read. If no key is input, data XF' is entered at X'01C' and X'018'. If there is any input, the data is 1 o'clock.
The details of this, stored in RAMX'01C' and X'018', are shown in the flowchart of Figure 6-1. This flow is based on the μPD757 specification, and each step corresponds to one step stored in the ROM. In step 7, the input data stored in step 6 is set at the necessary address in the RAM according to the contents. For example, when the key for magnification 0.7 is turned on, (X'01C') is 1, so bit 1 is set to (X'033') at 8, or 0.7. When the number key is 9, (X'018') is 9, so shift (X'02B') to X'02A', shift (X'02C') to X'02B',
Set 9 to X'02C'. At the same time as these settings are made, various modes are displayed in the same manner as in step 5. In Step 8, the paper feed section set in Steps 6 and 7 is determined by (X'052'), that is, 0 indicates the cassette, 4 indicates the deck, and the status of the paper detectors 60 and 61 of each section is determined. Check. 60,
Reference numeral 61 is a Cds that detects changes in light reflected by paper, and when there is no reflection, it is assumed that there is no paper. Then, as in step 3, the paperless lamp is turned on or off. In step 9, it is determined whether or not the positions of the lens system and mirror system correspond to designated positions.If they are not at the designated positions, the positions are changed (FIG. 5-2). Regarding step 16, the RAM data obtained in step 7 and the data obtained from the I/O 200 port are compared. In other words, (X′033′) and (X′043′) of RAM
Determine whether they are equal or not. If we now specify 0.7x and the lens system position is 0.7, then (X'033') is 1000 and (X'043') is 1000, which are equal.
When the position of the lens system is equal to the same magnification, the I/O 200I ₂ is 0, so (X'043') is 0000, and they are not equal, so the lens position is changed. First, the variable magnification motor
Turn on _M3 and turn on solenoid _SL3 for rotation lock to move the optical system. When the magnet attached to the lens reaches the position of sensor RD7, the I/O200
Since I ₂ becomes 1, motor M ₃ and solenoid SL ₁ are turned off. Also, set the data to X'043'. In step 10, when the lens system is at the specified magnification change position, the state of the power switch SW is determined to see if the control should be restarted. This is done by sensing port _I2 of I/O 100. When SW is off, return to start and clear RAM. In step 11, it is determined whether the paper exit position is at the specified position. When the exit is not in the designated position, the exit is changed (Figure 5-2). At step 18, the RAM data (X'032') and I/O data from step 7 are
300 I port data (X'042'). When (X′032′) and (X′042′) are equal, that is, it is a tray specification, and if there is something in the tray now, (X′032′) is 0010 and (X′042′) are 0010, which are equal.
When X′042′ is a sorter of 0001, they are not equal, so the exit is changed. First, the outlet motor M ₂ and rotary lock solenoid SL ₂ are turned on to move the outlet from the sorter toward the tray. When the magnet provided on the fixed shaft approaches the rotation of the roller of the belt 19 and the tray sensor 70 is turned on, 1 is input to the port _I0 of the I/O 300 to determine that the tray position has been reached. Then turn on motor _M2 solenoid _SL2 and set data to RAM X'042'. In step 12, it is determined whether a key counter is inserted or not, and whether or not the device has waited up (completed), based on the I/O 100 designation and sense, and it is checked whether copying is possible. Step 20 of 30 when copying is possible, exit, and after changing the magnification position.
Proceed to the step to set the standby timer in seconds.
Through this routine, a routine for checking key input, a paper-out check, and an exit magnification change position check routine are performed again. Step 13 is to determine whether or not the copy key 21 has been entered, and the corresponding RAM data in step 7 is determined. If there is no copy key input, proceed to step 14 and check whether another key is inserted (X′018′), (X′01C′)
)
Control is performed by checking whether or not is F. If there is still no evidence of any key input, proceed to step 15. If the routine up to this point is repeated about 3000 times, that is, the steps up to this point are about 1000 and each step is about 10 μsec, so 30 seconds will pass. Therefore, RAM
Store 3000 in WA(0) (step 20),
This is decremented by 1 every time step 15 is executed (15
-1), when it becomes 0, the program proceeds to the initial step STAT, clears the RAM, and sets the standard mode (step 2). In step 14, if a key entry is made during this 30 seconds, the step will start again.
20 is executed, 30 seconds are stored in RAM WA(0), and the above subtraction routine is performed. Details of steps 14 and 15 are shown in Figure 6-2. If you turn on the copy key during this time, the process advances to step 21 and the drum motor
M ₁ Turn on the high voltage transformer and start the copy operation. If a jam occurs during copying or if the paper in the deck or cassette runs out, the motor M ₁ and the high voltage transformer are turned off, but the process does not exit from step 21. Therefore, the RAM data is held and the display such as the number of sheets remains even if the power switch is turned off. At the end of each copying cycle (each time paper is fed), the counter COPY in the RAM is increased by 1 and the value is displayed on the display 23-2, and when it is compared with the counter SET and matches, the main motor M ₁ and high voltage transformer are turned off. do. Then proceed to step 20 and set a timer of 30 seconds. The timing at which _M1 is turned off and step 21 is exited is after the last paper has passed through the paper detectors 64 and 65. Also, even if you turn on the clear key when there is no jam or paper, it will skip step 21 and return to step 30.
Set seconds. After setting this for 30 seconds, if you do not want to enter the copy key or other keys, or if you have made a key entry and do not want to enter the next key, return to the STAT step and return to the standard mode. If you turn on the copy key within this 30 seconds, copying will be performed using the previous set number. In Figure 6-2, microstep 14-1
~14-4, the data of X′018′, that is, the same size, 0.7,
0.6, the input of the shading key, clear, cassette, deck, sorter, and tray key is determined, but in 14-3, the exclusive OR of the data stored in ACC and AC is taken and stored in ACC, and a match is found in F. ACC
becomes 0. Therefore, execute steps 14-5 to 14-8 to similarly determine the data of X'01C' and check the numerical keys.
Microsteps 15-1 to 15-3 are X'001' to
WA with X′003′ as a 3-digit working register
(0), this value is decremented by 1, and the decremented value is stored in WA (0) again. 15-4 to 15-6 is WA
Whether the upper digit of (0) is 0 or not, 15-7 to 15-9, 15
-10 to 15-12 are for determining whether the middle and lower digits of WA(0) are 0 or not, and returning to the start. FIG. 8-1 shows a variable magnification mechanism, in which a lens system 59 and a mirror 15 are reciprocated by rotation of a motor _M3 . Also, the positions of the lens 59 and mirror 15 are set according to the zoom specification, depending on the sensor RD1, RD7, RD6.
They move in conjunction so that a predetermined optical path length is achieved when the position is .
SL ₃ turns off when the optical system is in place and locks it from moving. Figure 9-1 is a time chart when moving from 1x to 0.6x. When the key is turned on, the RAM
Since (X′033′) is 4 and (X′043′) is 0, I/
Set O of O200 to 3 and turn on SL ₃ and M ₃ . I of I/O200 is Hall element RD1,
When it is determined by RD7 and RD6 that it has become 8 (I ₃ =1), SL ₃ and M ₃ are turned off. and
Set 4 to X'043'. FIG. 8-2 shows the exit changing mechanism, in which the belt 19 is moved up and down by the rotation of the motor _M2 .
The position of the belt 19 is determined by the sensor 7 according to the exit designation.
When 0,71 is on, it moves to a predetermined exit.
SL ₂ locks the outlet from turning off and moving when in place. Figure 9-2 is a time chart when moving from the tray to the sorter. When the key is turned on, the RAM
(X'032') is different from that, so set O of I/O 200, turn on SL ₂ and M ₂ , and as described above, by the signals of sensors 70 and 71, SL ₂ and M ₂ are turned off and set at a predetermined exit. As described above, the present invention displays conditions according to various key inputs, and if the process does not start within a predetermined time from the last key input, the display is cleared or the standard mode is displayed, thereby reducing image formation errors. , rapid restart of image formation can be expected. Figure 10 shows the jam determination step 21 in Figure 5-1.
-3 is a flowchart showing details. In step 31, a jam caused by a paper jam or the like in the paper path is detected. The paper sensors 62 to 67 in the copying machine and the paper sensors 68 and 6 in the sorter shown in FIG.
Step 9 is performed by sensing the sensor at a predetermined timing to determine whether or not the paper has arrived at the appropriate time. Each sensor outputs a signal 1 when a well-known optical detector detects paper. Reference numerals 67 and 62 are sensors for the paper feeding section, 66 and 63 are sensors for the conveying section, and 64 and 65 are sensors for the discharging section. If 1 is not sensed at a predetermined time, it is determined that there is a jam, and the process proceeds to step 32, where it is checked whether a reset button (not shown) in the main body is turned on to clear the jam. When it is on, the process advances to step 33, and the sensors 62 to 69 are scanned again to check whether there is still paper left. If it remains (step 34), an error flag is set in the RAM as an error mode, and FP is displayed on the segment display 23-1 for setting the number of copies (step 35). These steps 33 to 35 are performed by the sensor 62.
The paper is checked and displayed in the order of location from 1 to 3. When the sensors 62 and 63 detect the paper, the copy count segment display 23-2 displays the paper.
Displays E1 and E2 alternately. This routine corresponds to steps 11-5 to 11-7 in FIG. 11. Data is set in the area of the display operation RAM corresponding to the sensor where paper remains, and while the error flag cassette is set, that area is scanned and displayed. When the paper is removed, the same key input as in step 6 becomes possible (step 36), and when the copy key is turned on, the number of copies and the number of sets are compared in step 21-4, and the process moves to end or repeat the copying operation. When the clear key is turned on when the copy key is not turned on, the process proceeds to step 20, standby set, and the data entered by the key can be stored in the RAM. In other words, the magnification that was stored earlier,
Numerical data etc. are canceled and new data can be set. However, data cannot be set while the SW is on and the clear key is not turned on.
However, if the SW is turned off, the steps in Figure 5-1 will occur.
Return to STATE, clear RAM and wait. In this way, even if a jam is reset after a jam occurs, there is no need to clear a large number of image forming condition modes, and all are held, so there is no need to take the trouble of resetting the conditions. 11-1 and 11-2 are diagrams in which a diagnostic flow is provided between steps 11 and 12 of FIG. 5-1. That is, after turning on the power switch, it detects and displays whether paper remains in the paper sensor in the paper path, detects and displays a break in the temperature control thermistor of the fuser, and displays whether the side plate of the sorter is closed. It is possible to avoid an increase in trouble by detecting and displaying the information and checking in advance the parts that are not usually checked before copying can be started. At step 11-1 in the figure, the paper sensors 62 to 6 are
7 is scanned and sensed, and the data of each sensor is stored in a register. Also, the sensor 62 on the cassette side
Determine the presence or absence of paper in , and if there is paper,
Set data to X081 of RAM and set error flag to X080 (11-3). Next, the presence or absence of paper is determined by the sensor 62' on the deck side, and the same operation is performed (11-4). After detecting the presence of paper in the tray side discharge detection sensor 66 and the sorter side discharge detection sensor 67 and setting error flags, etc., check the operational amplifier (not shown) that outputs 1 due to a disconnection of the thermistor (11-5). ). When 1
Set the data in X091 of RAM and set the error flag in X080. Similarly, the sensor for detecting the disappearance of the cleaner web in the cleaning section is checked, and if no web is detected, the data is stored in the RAM and an error flag is set (11-6).
When a sorter is selected as an exit, it is checked whether the side plate of the sorter is open by turning off the door switch (11-7). After that, the jam detection sensor 68 installed at the sorter entrance and the sensor 69 installed on the sorter tray sense whether there is paper (11-9).
Performs storage work in RAM. Then, the set state of the error flag in the RAM is sensed, and when the error flag is set, the error mode is displayed on the segment displays 32-1 and 23-2 as described above.
(11-10). This step is the first
This step is similar to step 35 in FIG. 0, and details will be described later. Then repeat these routines. If the error flag is not set or if the flag is cleared by removing the paper on the sensor, the segment display 23-
At 1 and 23-2, the number of copy sets stored and the number of copies completed are displayed in the SET and COPY areas of the RAM, and the process exits to step 12. In FIG. 1, 72 is a web that is previously cleaned on the insulating drum 7 and is wound in the direction of the arrow. 7
3 is a well-known optical sensor that detects the end of the web and informs that there is no web, and its output is I/O50.
Input to I ₀ of 0. Also, 74 is a micro switch that turns on when the side plate of the sorter (opens and closes to take out paper) is completely closed, and its output is the same as that of I/O 300.
I input into ₂ . Further, 68 is a well-known optical sensor for detecting whether paper is jammed near the sorter entrance, and ₆₉ is a well-known optical sensor for detecting whether paper is jammed at each sorter.
is input. Jam detection paper detection sensor 62 to 67 I/O500, I/O6 in copying machine path
The thermistor disconnection detection signal is connected to I/O from I ₀ to _{I 3} of 00.
400 input into _I3 . The signals from each of the above sensors serve as conditions for display control as described above. Next, the error display operation (step 35) will be explained with reference to FIG. The keys and display chip UPD 757 used in the I/O 700 have a relationship between 4-bit hexadecimal code input and segment display as shown in Table 3.

【table】
Also, the relationship between the error contents and the segment display is as follows: 23-1, 23-1, 23-1, 23-1,
23-2 is displayed as FP, E1. Here, F on the display 23-1 means that the diagnostic program is being executed, and P on the right digit means that the diagnostic mode is jammed. When diagnostic mode is standby □
is displayed. E on the display 23-2 means an error symbol to be displayed when an abnormality is detected, and the digit 1 to the right of the blank indicates the location of the abnormality. 23-1 and 23-2 are displayed simultaneously. Therefore, corresponding to the paper sensors 62 to 69, E-
1 to E-8, web check sensor 78, sorter switch 74, and thermistor disconnection check sensor, E-9, E-10, and E-11 are displayed. If an abnormality occurs at multiple locations during jam or standby, for example, during standby, if sensor 63 and sensor 73 are abnormal, the display 23-1 will indicate F-0,
At step 23-2, E-2 and E-9 are displayed alternately. This operation will be explained using RAM with reference to FIGS. 7 and 12. When proceeding to the error display, perform step processing below the CPU. In step 35-1, write hexadecimal code XA to RAM address X0D3.
(BCD1010). This is I/O-
When decoded by the X700, it becomes E as a 7-segment display, and if this is output (displayed), it means that there is an abnormality in the diagnostic result. Hexadecimal code in X0D4 in step 35-2
Set up XF (BCD1111). This is KEY&
When decoded by Display I/O-X100, it becomes a frank. Next, X081 is specified as the RAM address and the process proceeds to step 35-3. In step 35-3, if the content of the RAM address specified in the previous step is 0, D0
Jump to specified RAM address +1
In other words, in the case of X081, it becomes X082 and the lower part of the address
Until the 4bit value becomes hexadecimal XA (BCD1010)
Rotate Step25. Here, if a value other than 0 is set at the specified address in RAM, the mode in which an abnormality was discovered as a result of the diagnosis in the previous step will be displayed.
The lower value of that address, i.e. 2 for X082
is set to X0D5, and data from X0D5 to X0D0 is sequentially output and displayed on I/O-X700. Then, hold the display for about 1 second, proceed to D0, and repeat the same process.
The lower part of the specified RAM address is hexadecimal XA
Repeat until (BCD1010) is reached. In other words, the display at step 35-2 and step 35-3 is RAM
The error modes set at addresses X081 to X089 are displayed sequentially at one-second intervals. For example, when there is paper in sensor 62 in standby diagnostic mode, the digit switching timing signal of I/O 700
The display data is set to F, -, 0, E, blank, and 1 corresponding to T ₀ , T ₁ , T ₂ , T ₃ , T ₄ , and T ₅ . Steps 35-4 to 35-6 are the same as 35-2.
RAM address X090 to X099, X0A0 to X0A9,
The error mode data set from X0B0 to X0B9 and from X0C0 to X0C9 is displayed sequentially at 1 second intervals. Note that since no data is stored in X0A1 to X0C9, the display is blank. As described above, according to the present invention, since the diagnostic operation is performed even after the abnormal state is canceled, the reliability of the apparatus can be further improved.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the image forming apparatus according to the present invention, FIG. 2 is a plan view of the operating section in FIG. 1, FIG. 3 is a control circuit diagram in FIG. 1, and FIGS. 4-1 to 4-5. is the input/output circuit diagram in Figure 3, Figures 5-1 and 5-2 are control flowcharts, and Figures 6-1 and 6-2 are the details in Figures 5-1 and 5-2. 7-1 and 7-2 are memory diagrams of FIG. 3, FIGS. 8-1 and 8-2 are partial sectional views of FIG. 1, and FIGS. 9-1 and 7-2 are Figure 9-2 shows each section 8-1 and 8-
Operation time chart in Figure 2, Figures 10 and 11
1, 11-2, and 12 are other control flowcharts, in which 14 is a tray, 18 is a sorter, 52 is a cassette, 53 is a deck, 9 is a paper feed roller, and 59 is a lens. series, 21 is the copy key,
22 is a number key, 28-1 to 28-3 are gray keys,
24 and 25 are exit designation keys, 26 and 27 are paper feed unit designation keys, and 30-1 to 30-3 are magnification designation keys.

Claims (1)

[Scope of Claims] 1. A conveying means for conveying a recording sheet, an image forming means for forming an image on the recording sheet conveyed by the conveying means, and a power switch operated to supply power to the image forming means. and, provided at multiple positions on the recording sheet conveyance path,
a plurality of detection means for detecting the presence or absence of a recording sheet for jam detection; and a plurality of detection means for controlling the conveying means and the image forming means to perform an image forming operation, and detecting the presence or absence of the recording sheet at a predetermined timing during the image forming operation. a control means having a program for detecting a jam in the recording sheet based on the output of each of the detection means and stopping the operation of the conveying means and the image forming means when a jam is detected; and supplying power to the control means. and a reset means for releasing the jam state in response to a predetermined operation. In response to the ON operation of the power switch, and in response to the jam release operation by the reset means after detecting a jam on the recording sheet, each of the plurality of detection means If any of the detection means detects a recording sheet, it prohibits the start of image forming operation, displays that a recording sheet remains, and detects the recording sheet. An image forming apparatus characterized in that when no recording sheet is detected in any of the above, image formation can be started.