KR940002424B1 - Electrophotographic apparatus - Google Patents

Abstract

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Description

Electrophotographic device

1 is a view showing the internal structure of a laser printer according to an embodiment of the present invention,

FIG. 2 is a diagram showing the configuration of the laser scanner unit shown in FIG.

3 is a block diagram showing a control circuit of this laser printer,

4 is a circuit diagram specifically showing a part of the control circuit shown in FIG.

FIG. 5 is a diagram showing the contents of the process condition data table stored in the ROM shown in FIG.

FIG. 6 is a diagram showing a main memory area of the RAM shown in FIG.

FIG. 7 is a diagram showing the configuration of the operation unit shown in FIG.

8B to 10B are flowcharts for explaining the operation of the control circuit shown in FIG.

The present invention relates to a dry electrophotographic apparatus such as, for example, a laser printer.

In recent years, a drum unit is used in a laser printer. The drum unit includes a photosensitive member, a charging unit, a developing unit, a transfer unit, and the like, and is detachably attached to the apparatus main body. The above-mentioned processing part, especially the photosensitive member, deteriorates depending on the frequency of use, and needs to be replaced with a new one when the service life is reached. Since this laser printer can be processed by replacing the unit for the life of the photosensitive member, there is an advantage that the maintenance work can be simplified.

In order to confirm whether the photosensitive member has reached the end of its life, a technique of counting the number of prints for each operation of the printer as the photosensitive member usage history, and using a memory element for displaying the count value, is known (Patent No. 62-75468). See publication number). By using this technique, the operator can recognize the deterioration degree of the photosensitive member more accurately than the usage period based on the current number of prints, and when a warning display or the like confirms that the number of prints has reached the preset print limit Replace the drum unit. By doing in this way, the fall of the print quality by deterioration of a photosensitive member can be reliably prevented previously.

By the way, when a manufacturer ships this kind of laser printer as a product, printing is actually performed several times beforehand to check printing quality and the like. In this test, some number of prints are stored in the memory device. Since it is not preferable to ship the product in this state, the conventional memory device is taken out of the preater after this inspection, and the print quantity data stored in this memory device is cleared to "0" using the dedicated read / write device. . The laser printer is shipped after the memory device initialized in this way is mounted again. In the maintenance check of this printer, there is a test whether a warning is displayed when the number of printed sheets reaches the limit of printed sheets. In this case, this test is carried out by temporarily embedding a separate memory device in which the print number data desired to be close to the print limit number by a dedicated read / write device is temporarily built into this printer, and printing the print limit up to the print limit number of copies. This has been done.

According to such a prior art, when it is necessary to temporarily change the use history information of the photosensitive member during inspection or maintenance at the manufacturing stage of the printer, a dedicated read / write device must be used, and workability is poor. .

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic apparatus that can facilitate inspection and maintenance at the time of shipment.

The object is to form an electrostatic latent image on the photosensitive member having a cabinet and a drum unit detachably attached to the cabinet and including at least the photosensitive member to attach the toner to the photosensitive member in response to the electrostatic latent image to transfer the toner image onto the paper. A recording unit for storing the usage history information of the photosensitive member included in the mounted drum unit, a notifying unit for notifying that the usage history stored in the recording medium reaches a predetermined value determined in correspondence with the life of the photosensitive member, and recording. This is achieved by an electrophotographic apparatus having a rewriting section for temporarily setting usage history information stored in the medium to a value close to this predetermined value.

In this electrophotographic apparatus, a value close to a predetermined value determined for the life of the photosensitive member can be set in inspection and maintenance at the time of shipment. Therefore, by repeating the printing operation several times in succession of this setting, it is easy to test whether the notification unit works properly, and it is not necessary to allow a special device for this test.

Hereinafter, a laser printer according to an embodiment of the present invention will be described with reference to the drawings.

1 schematically shows the structure of this laser printer. This laser printer has a printer cabinet (1), and further includes a drum unit (2), a laser scanner unit (5), a transfer charger (7), a paper feed unit (10), a pickup roller (11), and a fixing machine (in the cabinet). 12), discharge roller 13, conveying motor 14, fan 15, interlock switch 16, and direct current power source 17. The drum unit 2 includes a photosensitive drum 3, a charging charger 4, a developing device 6, a cleaning device 8, and an antistatic lamp 9, and is detachably attached to a central portion of the printer cabinet 1. It is mounted. The photosensitive drum 3 has a photosensitive member surface and is driven to rotate in one direction in the printing operation. The charging unit 4, the laser scanner unit 5, the developing unit 6, the transfer charger 7, the cleaning device 8, and the antistatic lamp 9 are in a state in which the drum unit 2 is mounted in the cabinet 1. Is positioned around the photosensitive drum 3 and used for performing a series of transfer photographing processes. The charging charger 4 charges the photosensitive member surface, and the laser scanner unit 5 selectively forms the photosensitive member surface by a laser beam irradiated corresponding to the printing information to form an electrostatic latent image. The developer 6 supplies the toner as a developer to the photosensitive member surface of the photosensitive drum 3, and visualizes the electrostatic latent image as a toner image by the toner attached to the photosensitive member surface corresponding to the electrostatic latent image. The transfer charger 7 charges the sheet and transfers the toner image onto the sheet by electrostatic attraction. The cleaning apparatus 8 removes the charge on the photoreceptor surface of the photosensitive drum 3 after the transfer. The paper feeding unit 10 is set in front of the transfer charger 7, and in turn is set in the rear of the fixing unit 12, the discharge roller 13, and the transfer charger 7. Each sheet is taken out by the pickup roller 11 one by one from the sheet feeding unit 10 for each printing operation, and is conveyed toward the transfer charger 7 at a predetermined timing. The fuser 12 applies heat and pressure to the paper to fix the toner image transferred to the paper.

The laser scanner unit 5 includes a laser diode structure 21 for generating a laser beam, a laser control circuit 22 for driving the laser diode structure 21, and an irradiation start position of the laser beam as shown in FIG. A start sensor 23 using a PIN diode for detecting a signal, a polygon motor 24 for rotating a polygon mirror, a polygon motor driving circuit 25 for driving and controlling the motor 24, and driven by the motor driving circuit. And a PLL control circuit 26 for controlling the rotation speed of the motor 24.

3 schematically shows a control circuit of this laser printer. This control circuit includes a CPU (central processing unit) 31 which performs various data processing necessary for the circuit of the printing operation, a ROM (lead only memory) 32 storing data such as a control program and various tables of the CPU 31. ), RAM (random access memory) 33, I / O (input / output) port 34, which temporarily store printing information sent from an external host computer, and data input / output to the CPU 31, and connecting them Bus line 35. The I / O port 34 has a motor drive circuit 36, a laser scanner unit 5, a high voltage power supply circuit 37, a sensor driver 40, an operation unit OP, and a paper sensor 42, 43, 44. The fan 15, the interface 45, and the recording unit RD are respectively connected.

The motor drive circuit 36 drives and controls the transfer motor 14, and the high voltage power supply circuit 37 supplies a high voltage to the developing device 6, the charging charger 4, and the transfer charger 7, and the sensor driver ( 40 drives the toner amplifier sensor 38 and the toner pull sensor 39 formed in the developer 6, and the paper sensors 42, 43, 44 are arranged to be distributed so as to detect the jam of the paper, and the interface ( 45) receives the argument start command and the argument information from the host computer. The recording unit RD records the printing number data A indicating the usage history of the photosensitive drum 3 and the printing limit number B indicating the replacement time of the drum unit 2, and are retained even when the printer is turned off. The interlock switch 16 is inserted into a power supply line for supplying a voltage of 12 V from the DC power supply 17 to the motor drive circuit 36, the laser scanner unit 5, the high voltage power supply circuit 37, and the fan 15. The upper part of the printer cabinet 1 is used to detect that the upper part of the printer cabinet 1 is released by rotation and to cut off this power supply.

4 shows a specific configuration of a part of the control circuit. In the circuit of FIG. 4, the CPU 31 accesses the memory card 51 via the card interface 52, directly accesses the ROM 32 and the RAM 33, and furthermore, the operation unit 41. Is accessed via the operation unit interface 53. The memory card 51 is used as an information recording medium detachable from the interface 45, and has an area for storing the number of print data A and the limit B of printing. The CPU 31 sets the reference voltage of the charging voltage power supply 56 for the charging charger 4 to the D / A (digital / analog) converter 55, and transfer voltage power supply for the transfer charger 7 ( 56 is set to the D / A converter 7 and the reference voltage of the bias voltage power source 58 for the developer 6 is set to the D / A converter 59, and the laser control circuit 22 The laser output is set to the D / A converter 60. In the initial state, the memory card 51 stores " 0 " as the printing number data A, and stores, for example, " 10000 " that is determined corresponding to the life of the photosensitive drum 3 to be used, for example, as the printing limit number B. . The number of print data A is increased by the same number as the number of prints for each print operation of the printer. The ROM 32 has an area constituting the process condition data table 70 shown in FIG. This table 70 includes electrophotographic process condition data # 1, # 2 which is selectively used corresponding to the number of prints A to compensate for the deterioration in print quality due to deterioration of the photosensitive drum 3.

These electrophotographic process condition data # 1, # 2 are the reference voltage value data of the charging voltage power supply 54, the transfer voltage power supply 56, and the bias voltage power supply 58, and the laser output value of the laser control circuit 22, respectively. Constructed from data. The RAM 33 stores the print number memory 71 which temporarily stores the print number display A ', as shown in FIG. 6, and the setting flag F set to "1" when the data setting mode is selected. It has an area constituting the flag memory 72 or the like. As shown in FIG. 7, the operation unit 41 has a power switch 81, a data setting mode selection switch 82, a set key 83, a reset key 84, an up key 85, and a down key 86. ) And a liquid crystal display clay 87 are formed. This liquid crystal display 87 displays the number of prints A stored in the memory card 51.

Next, the operation of this laser printer will be described.

The CPU 31 is programmed to perform the operation shown in FIG. 8 when the power is turned on by the operation of the power switch 81. When this operation is started, the CPU 31 first executes an initialization process of clearing data in the RAM 33 and resetting the I / O port 19, for example. Then, the state of the data setting mode selection switch 82 is checked. When the switch 82 is in the ON state and the data setting mode is selected, the data setting flag F stored in the flag memory 72 of the RAM 33 is set to "1". When the switch 82 is in the OFF state and the data setting mode is not selected, the data setting flag F stored in the flag memory 72 of the RAM 33 is reset to "0". After the set or reset of the flag F, the CPU 31 executes the print preparation and print processing.

In this print preparation process, the CPU 31 periodically performs the print decision processing shown in FIG. 9 and the key determination process shown in FIGS. 10A and b.

When the print determination process is started, the CPU 31 first checks whether a print start instruction is set. If no argument start instruction is set, this argument determination processing is completed.

When the CPU 31 detects that the print start instruction is set, the CPU 31 accesses the memory card 51 and reads the print number data A and the print limit number B recorded on the card 51.

When the print quantity data A is "0" or more and less than the print limit number of copies B / 2, the electrophotographic process condition data # 1 is read out, and the data contained in this data # 1 are respectively D / A converters 55, 57, 59. 60). That is, "-6000V" is set to the D / A converter 55 as the reference voltage of the charging voltage power supply 54. In the D / A converter 57, "-5000V" is set as the reference voltage of the transfer voltage power supply 56. In the D / A converter 59, " -300 V " is set as the reference voltage of the bias voltage power source 58. In the D / A converter 60, "3 ms" is set as the laser output of the laser control circuit 22. As shown in FIG.

When the number of sheets of print data A is greater than the number of sheets of print limit limit B / 2 or less than the number of sheets of print limit number B, the electrophotographic process condition data # 2 is read out, and the data included in the data # 2 are respectively D / A converters 55, 57, 59. 60). That is, "-7000V" is set to the D / A converter 55 as the reference voltage of the charging voltage power supply 54. In the D / A converter 57, "-6000V" is set as the reference voltage of the transfer 56. As shown in FIG. In the D / A converter 59, " -400 V " is set as the reference voltage of the bias voltage power source 58. As shown in FIG. In the D / A converter 60, " 4 kHz " is set as the laser output of the laser control circuit 22. As shown in FIG.

As described above, the CPU 31 sets the data in the D / A converters 55, 57, 59, and 60, and then ends the print determination processing to execute the print processing. In this printing process, in order to perform a series of electrophotographic processes, the charge charger 4, the laser control circuit 22, the developer 6, and the transfer charger 7 respectively correspond to the D / A converters 55, 57, 59. (60) is operated sequentially, and the image is printed on the paper according to the printing information sent from the host computer. After the one-time printing operation is completed, the printing number data A is incremented by " 1 " in the memory card 51. As shown in FIG.

When it is detected that the print number data A has reached the print limit number B, the CPU 31 displays a message prompting the exchange of the photosensitive drum 3 on the liquid crystal display 87 and prohibits subsequent printing operation. In addition, when the printing number of sheets A exceeds the printing limit number of sheets B, an abnormality in the information recorded on the memory card 51 is displayed on the liquid crystal display 87 and subsequent printing operation is prohibited.

When the key determination processing is started, the CPU 31 checks whether the data setting key, that is, the set key 83, the reset key 84, the up key 85, and the down key 86, is operated in step ST1. do.

If data setting key operation is detected in step ST1, the CPU 31 determines that the reset key 84 is operated, the data setting flag F is set to "1", and the set key 83 is not operated. After confirming, the initialization operation of the memory card 51 is performed. In this initialization operation, the print number data A of "0" and the print limit number B of "10000" are stored in the memory card 51. The CPU 31 ends the key determination processing only after this storage.

When an operation of the data setting key is detected in step ST1, the CPU 31 does not operate the reset key, the set key 83 is operated, and the data setting clag F is set to "1". A check operation is performed to change the print quantity data A. In this changing operation, the print number data A is read from the memory card 51 and stored in the print number memory 71 of the RAM 33 as processing data A '. This process data A 'is read out from the print number memory 71 and flashes on the liquid crystal display 87 for display. Thereafter, the CPU 31 repeatedly executes steps ST2, ST3, and ST4 and waits for the operation of the data setting keys 83, 85, and 86 except for the reset key. When it is detected in step ST2 that the up key 85 has been operated, " 100 " is added to the process data A 'stored in the print number memory 71. After this addition, the data A 'is read out from the memory 71 and flashed on the liquid crystal display 87 to be displayed.

The CPU 31 waits for the next key operation after this display operation. If it is detected in step ST3 that the down key 86 has been operated, " 100 " is subtracted from the process data A 'stored in the print number memory 71. After this subtraction, the data A 'is read out from the memory 71 and flashed on the liquid crystal display 87 to be displayed. The CPU 31 waits for the next key operation after this display operation. If it is detected in step ST4 that the set key has been operated, the data A 'stored in the printing number memory 71 is stored in the memory card 51 as the printing number data A and is displayed on the liquid crystal display 87 without blinking. do. The CPU 31 ends the key determination processing following this display operation.

If the operation of the data setting key is detected in step ST1, the CPU 31 confirms that the reset key and the set key 83 are operated and that the data setting flag F is set to " 1 " The change operation of the limit number data B is performed. In this changing operation, the print limit number of copies data B is read from the memory card 51, and stored in the print limit number of copies memory 88 of the RAM 33 as processing data B '. This process data B 'is read from the print limit number-of-memory memory 88, and flashes on the liquid crystal display 87 to be displayed.

Thereafter, the CPU 31 repeatedly executes steps ST5, ST6, and ST7 to wait for the data setting keys 83, 85, and 86 to be operated except for the reset key. When it is detected in step ST5 that the up key 85 has been operated, " 100 " is added to the process data B 'stored in the print limit number of copies memory 88. After this addition, the data B 'is read out from the memory 88, and flashes on the liquid crystal display 87 to be displayed. The CPU 31 waits for the next key operation after this display operation. If it is detected in step ST6 that the down key 86 has been operated, " 100 " is subtracted from the process data B 'stored in the print limit number of copies memory 88. After this subtraction, the data B 'is read out from the memory 88 and flashes on the liquid crystal display 87 to be displayed. The CPU 31 waits for the next key operation after this display operation. When it is detected in step ST7 that the set key has been operated, the data B 'stored in the print limit number of copies memory 88 is written into the print limit number of copies data B by the memory card 51, and also flashes on the liquid crystal display 87. Is displayed. The CPU 31 terminates the key determination processing following this display operation.

In addition, when it is detected in step ST1 that no key has been operated, when it is detected that keys other than the set key 83 and the reset key 84 have been operated, or the data setting flag F is set to "0". When it is detected that it has been reset, the CPU 31 does nothing and ends the key determination process.

In the above-described laser printer, when the power is supplied by the power switch 81 while the data setting mode switch 82 of the operation unit 41 is turned on, the data setting clad F is set to "1" and the data setting mode is set. Is selected. Thereafter, when the reset key 84 in the data setting key is operated, the printing number data A recorded in the memory card 51 mounted in the card interface 52 is reset to " 0 ".

Therefore, even if the manufacturer prints the laser printer to check printing quality or the like before shipping, the power switch 82 is turned ON after the data setting mode selection switch 82 is turned on after this printing operation. By operating the set key 84, the printing number data A in the memory card 51 formed in this printer can be cleared to " 0 ". In other words, the printer can initialize the memory card 51 in a simple operation without allowing a read / write device. Therefore, work efficiency can be improved in the case of inspection before shipment.

In this laser printer, when the key 83 of the data setting keys is operated while the data setting mode is selected, the printing number data A is read from the memory card 51 attached to the card interface 52, and the RAM ( 33 is temporarily stored in the print number memory 71 as processing data A 'and flashes on the liquid crystal display 87 for display. When the up key 85 is operated in this state, " 100 " is added to the processing data A 'in the printing number memory 71, and the added processing data flashes and is displayed on the liquid crystal display 87. FIG. When the down key 86 is operated, " 100 " is subtracted from the processing data A 'to the print number memory 71, and the processing data A' after subtraction is displayed on the liquid crystal display 87 by blinking. Then, when the set key 83 is operated again, the contents of the printing sheet memory 71 do not flash on the liquid crystal display 87 in the memory card 51 mounted on the card interface 52 at this point. Is displayed.

Therefore, in the maintenance check of the laser printer, when it is necessary to test whether or not a warning is displayed when the number of printed sheets reaches a predetermined value determined according to the life of the photosensitive drum 3, that is, the printing limit number of sheets B, The data setting mode selection switch 82 is turned on, and in this state, the power switch 81 is turned on, and then the set key 83 is operated. Then, the printing number data recorded on the memory card 51 in correspondence with the drum unit 2 currently mounted is displayed blinking on the liquid crystal display 87, and this is recorded on a memo sheet or the like. Next, when the up key 85 is operated repeatedly, the number of prints increases in units of "100" in the liquid crystal display 87. After the set number 83 is operated again after the number of prints is close to the number of print limit, this number of prints is stored in the memory card 51. Therefore, it is possible to confirm whether or not a message prompting drum replacement is displayed by actually printing up to the printing limit limit number of sheets.

When this confirmation is completed, the set key 83 is operated again with the data setting mode selected. When the down key 86 is operated repeatedly, the number of prints is reduced by " 100 " units in the liquid crystal display device 87. FIG. The number of prints recorded on the memo sheet is returned to the number of test prints plus the number of tests printed for the confirmation of the warning display, and when the set key 83 is operated again, the number of prints is printed on the memory card 51. Is remembered. In this laser printer, the use history of the photosensitive drum 3 can be returned to the same value as before the maintenance inspection. In this way, it is possible to check whether a warning is displayed when the number of prints reaches the limit of printing in the maintenance check by simple key operation without intention of the read / write device. Thus, maintenance work is easier than in the prior art.

In this type of maintenance inspection, the memory card that is currently mounted may be removed, a separate memory card may be installed, and the number of print data stored in the memory card may be changed.

In this laser printer, when the set key 83 and the reset key 84 among the data setting keys are operated while the data setting mode is selected, the print limit number of copies data B is mounted on the card interface 52. The memory card 51 ) Is temporarily stored as the processing data B 'in the print limit number-of-memory memory 88 of the RAM 33, and flashes and is displayed on the liquid crystal display 87 at the same time. In this state, when the up key 85 or the down key 86 is repeatedly operated, the processing data B 'is increased or decreased in units of "100" in the printing number memory 71, and the processing data after the increase or decrease is blinking on the liquid crystal display 87. Is displayed. Subsequently, when the set key 83 is operated again, the contents of the print limit copy memory 88 are stored as the print limit copy number display B in the memory card 51 mounted on the card interface 52 at this time. This limit printing number data B is displayed on the liquid crystal display 87 without blinking.

Since the printing limit number B can be changed in this manner, it is possible to cope with the case where the new drum unit has a photosensitive drum 3 having a different life from before replacement.

In addition, this invention is not limited to the above-mentioned embodiment, It is possible to deform | transform into various forms in the range which does not deviate from the paper. In this embodiment, the up key 85 and the down key 86 are formed to increase or decrease the number of print data stored in the memory card 51 in units of "100", for example, directly inputting a desired value of 10 keys. It may be formed in order to. In addition, although the memory card 51 is used as an information recording medium, it can be replaced by, for example, a magnetic tape or a semiconductor memory. This semiconductor memory includes power-backed RAM and EEPROM. Further, the present invention can be applied not only to the laser printer of the embodiment, but also to a copying machine using a drum unit including, for example, a photosensitive member and detachable to and from a cabinet.

Claims (4)

An electronic photograph having a cabinet and a drum unit detachably mounted to the cabinet, the drum unit including at least a photoconductor, forming an electrostatic latent image on the photosensitive member, and attaching toner to the photosensitive member corresponding to the electrostatic latent image to transfer the toner image onto paper. A processing unit, a nonvolatile recording medium storing at least usage history information of the photoconductor included in the mounted drum unit, and a notification means for notifying that the usage history stored in the recording medium has reached a predetermined limit corresponding to the life of the photoconductor. And rewriting means for setting the usage history information stored in the recording medium to a value close to this limit. An electrophotographic apparatus according to claim 1, wherein the recording medium again stores the limit value, and the rewriting means has means for changing the limit value. The electrophotographic apparatus according to claim 1 or 2, wherein said rewriting means has means for returning usage history information to an initial value. 2. The rewriting means according to claim 1, wherein the rewriting means reads the information stored in the input unit, the memory, and the recording medium into the memory, changes the information stored in the memory according to an operation of the input unit, and changes the changed information. An electrophotographic apparatus comprising a processing unit for storing in a recording medium.

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