JPH02230262A - Controller for electrophotographic image forming machine - Google Patents

Abstract

PURPOSE:To recover an image formation state into an excellent state only by easy operation by providing a control means which controls the operations of a photosensitive drum rotating means, an electrostatic charging means, an erasure lamp, and a toner supply means respective in response to specific operations. CONSTITUTION:A CPU 3 operates according to a program stored in a program ROM 5, inputs respective pieces of information from an operation part 7, an ATDC sensor 9, etc., and stores them in a working RAM 11, etc. Then the CPU 3 controls the operations of the photosensitive drum rotating means 13, electrostatic charging device, erasure lamp 10, toner supply means 20, developing sleeve 2A, etc., according to the program and various pieces of information. Consequently, even if the image formation state becomes abnormal and its cause is not found, the image formation state can be recovered into the excellent state only by the easy operation.

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a control device for an electrophotographic image forming machine suitable for maintaining a good image forming state of the electrophotographic image forming machine. <Prior Art> In an electrophotographic image forming machine, cases in which a good image cannot be obtained can be considered, for example, in the following cases. ■Various conditions for development are normally set on the assumption that the photosensitive drum is not damp, so if the photosensitive drum becomes damp, the density will not increase in regular development, and in reversal development. Problems such as the entire image becoming slightly foggy occur. ■In the development process using a two-component developer, the mixing ratio of toner to carrier greatly affects the image condition. If the mixing ratio becomes extremely low, the density will not increase in both normal development and reversal development, and conversely, the mixing ratio of toner to carrier will greatly affect the image condition. If the ratio is extremely high, the entire image will become a little foggy. ■In an electrophotographic image forming machine equipped with two or more developing devices, the developer set in one developing device mixes with the developer set in Ikekata's developing device (contamination).
As a result, a defect occurs in the image condition. Therefore, in order to improve a defective image condition, it is necessary to look at the image condition (image noise, etc.), infer the cause, and take recovery measures to eliminate the cause. <Problems to be Solved by the Invention> However, it is difficult for general users to infer the cause of image defects from the image condition, and it is difficult for ordinary users to take necessary recovery measures as soon as possible. Therefore, some kind of countermeasure has been desired.An object of the present invention is to provide a simple solution even when the image forming state of an electrophotographic imager becomes defective and the cause is unknown. An object of the present invention is to provide a device for an electrophotographic image forming machine that can restore the image forming state to a good state simply by performing an operation. In order to achieve this, the electrophotographic image forming machine according to the present invention is an electrophotographic image forming machine control device that controls the electrophotographic image forming machine, and includes: a photosensitive drum rotation means for rotating a photosensitive drum; A charging device that charges the photosensitive drum, an erase lamp that removes static electricity from the charged photosensitive drum, and a toner replenishing unit that detects that the toner to carrier mixing ratio has fallen below a desired value and replenishes toner to the developing device. and, in response to a predetermined operation, the photosensitive drum rotating means, the charging position H,
A control means for controlling the operations of the erase lamp and the toner supply means, respectively. <Function> In the control device for an electrophotographic image forming machine according to the present invention, by simply performing a predetermined operation, the control means can control the photosensitive drum rotation means,
The operation of the charging device, erase lamp, and toner replenishing means is automatically controlled. <Embodiments> Hereinafter, preferred embodiments of a control device for an electrophotographic image forming machine (hereinafter abbreviated as a control device) according to the present invention will be described based on the drawings. FIG. 1 shows an overall schematic diagram of a reader printer LP to which a control device according to the present invention is applied. In the figure, the reader printer LP has a film F.
It consists of an optical system that projects an image of the film F onto a screen S, and a printer system that develops, transfers, and fixes the image of the film F onto the paper PA. In this optical system, the light emitted from the film F is transmitted through the magnifying lens L and the prism P, and then reflected by the rotatable mirror P1 toward the mirror R1, and the reflected light is further reflected by the mirror R1. and an image is formed on the screen S. Incidentally, when the image of the film F is projected onto the screen S as a reader, the mirror P1 is in the position shown by the solid line in the figure. On the other hand, during printing, in which the image of the film F is developed, transferred, and fixed onto the paper PA, the mirror P1 is rotated in the direction a in the figure, which is indicated by a dotted line. In that case, the light reflected by mirror P1 passes through three mirrors P
2, P3, and P4, and an image is formed on the circumferential side of the photosensitive drum D while scanning the image. As can be understood from FIG. 2, in the above printer system, a P-P (positive-positive) developer is placed at a desired position around the photosensitive drum D, which is rotated by a known drive mechanism (drum rotation means). 2, a developing device 4 for N-P (negative-positive), a charging device consisting of a main charger 6 and a transfer charger 8, and an erase lamp 1
0 and a cleaning unit 12 are respectively provided. Further, below the photosensitive drum D, a paper PA is placed on the photosensitive drum D.
A paper feed cassette 16 for supplying the paper PA is installed, and a paper discharge tray l8 on which the developed paper PA is placed is provided at the most downstream position along the transport direction of the paper PA. As understood from FIG. 3, the developing sleeve 2
For developing devices 2 (and 4) having A (and 4A), a mixing ratio (toner concentration) of carrier and toner, which are two types of developer components set in developing devices 2 (and 4), is detected. A well-known ATDC sensor 9 is provided, and the developing device 2 (and 4) is provided with a toner replenishing means 20 mainly composed of a toner replenishing screw TS, a developer stirring screw DS, etc. It is designed to be refilled with toner. FIG. 4 shows a system block diagram of the main electrical configuration of the control device 1 in this embodiment. In the figure, a CPU 3 functioning as a control means operates according to a program stored in a program ROM 5, takes in information from an operation unit 7, an ATDC sensor 9, etc., and stores it in a working RAM 11. Based on these programs and various information, the CPU 3 controls the operations of the photosensitive drum rotating means 13, the charging device, the erase lamp 10, the toner replenishing means 20, the developing sleeves 2A and 4A, and the like. The operation unit 7 is provided with a switch for operating the reader printer LP, various switches for operating the control device 1, and the like. The control device 1 is configured as described above, and in this embodiment, the photosensitive drum D is dried and the toner is removed according to the developing state when the drum dry switch 7A is pressed, according to the sequence shown in Tables 1 and 2. Execute replenishment at the same time. In Table 1; ■ Regarding the main CH (charging by the charging device 6), in order to avoid toner consumption during sequence execution, regular development (
Charging is not performed when the photosensitive drum is developed in a charged area, and charging is performed when reversal development is performed (development is performed on an uncharged area of the photosensitive drum). (2) Transfer CH (charging by transfer charger 8) is carried out only in regular development because the transfer charge and main charge have opposite polarities in reversal development and damage the photosensitive drum D in reversal development. (2) The developing bias is applied only to the P-P developing device 2 or the N-P developing device 4 used for both regular development and reversal development. (2) Erasing (light, static elimination) must be performed at both regular development and reversal development since charging is performed, and the heat from the erase lamp 10 is also necessary to dry the photosensitive drum D. (2) Regarding the rotation of the developing sleeve 2A (or 4A.), only the developing sleeve of the developing device used for both regular development and reversal development is rotated (detailed explanation will be given later). In Table 2: ■ Regarding the presence or absence of spike cutting, it is necessary to prevent the developer in the developing device that is not used in both developments from being developed on the photosensitive drum D, and in this example, as can be understood from FIG. Ear cutting shutters 2B and 4B are provided which can move toward and away from the developing sleeve bar and 4A, respectively. Then, the developer on the developing sleeve is removed by cutting the developer on the developing sleeve 2A or 4A of the non-operated developing device with the ear cutting shutter 2B or 4B. ■T/C detection/replenishment (toner mixture ratio detection/toner replenishment)
If it is detected that the toner mixing ratio is low based on the output voltage value of the ATDC sensor of the developing device used in both development, toner is replenished to the developing device.

[Table 1]

[Table 2] The processing to be performed next by the CPU 3 is shown in Figures 5, 6, and 7.
The explanation will be given according to the flowchart shown in the figure. In FIG. 5, when desired initial setting values are input from the operation unit 7 (step 100), the reader printer LP
is placed in the leader state (step 10l). When the print switch 7A provided on the operation unit 7 is turned on (step 102, affirmative), the reader printer LP is caused to perform a normal printing operation (step 103). Here, on the condition that the print switch is "off" and the drum dry switch 7B provided in the operation section 7 is "on" (step 102 negative, step 104 W fixed), the rapid A process for drying the photosensitive drum D (drum drying) including toner replenishment and contamination recovery is performed. The drum drying is performed depending on the development mode currently selected by the selection switch 7C provided on the operation unit 7. If it is normal development, the process proceeds to step 200, while if it is reverse development, the process proceeds to step 300 (step 106). . In the P-P drum drying shown in FIG. 6, first, the ear-cutting shutter 4B of the N-P developing device 4 is turned on (step 20l), the timer 1 in the CPUa is set (step 202), and the developing device The developing sleeve 4A of No. 4 is rotated (step 203), and the rotation of the developing sleeve 4A is stopped after waiting for the timer 1 to time up (step 204, affirmative) (step 205). That is, in steps 201 to 205, if the developer in the developing device 4 faces the drum, the developer will be consumed, so the developing sleeve 4A of the developing device 4 is cut. In the next step 206, the timer 2 is set, and while the photosensitive drum D is being rotated, the transfer charger 8 is turned on.
As a result, the eraser ramp lO is turned on (step 207, step 208, step 209, step 210), and the photosensitive drum D is given a charging condition under which the developer in the P-P developing device 2 is not developed. It will be done. The charging condition under which the developer in the developing device 2 is not developed is the condition in which the developer in the developing device 4 is developed. Not done. Next, when the developing sleeve 2A of the developing device 2 is rotated, the developer of the developing device 4 that has been contained in the developing device 2 for some reason is developed on the photosensitive drum D, and the contamination is recovered (step 211). Then, the developer stirring screw DS that replenishes toner to the developing sleeve 2A of the developing device 2 is rotated, and the toner mixing ratio is detected by the ATDC sensor 9 (step 21).
2, step 213). If the toner embedding ratio is less than a predetermined value (in this embodiment, the value is 6%) (No in step 214), toner is replenished by the toner replenishment screw TS (step 216), and the timer 2 is set. After waiting for the developer to move up (step 215, affirmative), the developer stirring screw DS is stopped (step 217). Furthermore, the developing sleeve 2A is stopped (step 218
), the developing bias, eraser lamp 10, and transfer charger 8 are set to "off" (step 219, step 2
20, step 22l), stop the photosensitive drum D (
Step 222) Return to normal processing. Next, in the N-P drum drying shown in FIG. 7, the ear cutting shutter 2B of the developing device 2 is turned on (step
1), the timer 1 in the CPUa is set (step 302), the developing sleeve 2A of the developing device 2 is rotated (step 303), and after waiting for the timer 1 to time up (
(Step 304W) The rotation of the developing sleeve 2A is stopped (Step 305). That is, in steps 301 to 305, if the developer in the developing device 2 faces the drum, the developer will be consumed, so the tip of the developing sleeve 2A of the developing device 2 is cut. In the next step 306, the timer 2 is set, and while the photosensitive drum D is being rotated, the main charger 6 is turned on and the eraser lamp 10 is turned on (steps 307, 308, and 309). , step 310), a charging condition is applied to the photosensitive drum D under which the developer in the developing device 4 is not developed. The charging condition under which the developer in the developing device 4 is not developed is the condition in which the developer in the developing device 2 is developed. Not done. Next, when the developing sleeve 4A of the developing device 4 is rotated, the developer contained in the developing device 2 for some reason is developed on the photosensitive drum D, and the contamination is recovered (step 31l). Then, the developer stirring screw DS that replenishes toner to the developing sleeve 4A of the developing device 4 is rotated, and the toner mixing ratio is detected by the ATDC sensor 9 (step 31).
2, step 313). If the toner mixing ratio is less than a predetermined value (in this embodiment, the value is 6%) (No in step 314), the toner is replenished by the toner replenishment screw TS (step 316), and the timer 2 is timed out. After waiting (step 315 affirmative), the developer stirring screw DS is stopped (step 317). Furthermore, the developing sleeve 4A is stopped (step 318
), the developing bias, the erase lamp 10, and the main charger 6 are turned off, step 319, step 3
20, step 32l), stop the photosensitive drum D (
Step 322) Return to normal processing. As explained above, in this embodiment, by simply operating the switch provided on the operating section 7, the photosensitive drum rotating means I
3. The charging device consisting of the main charger 6 and the transfer charger 8, the erase lamp 10 and the toner replenishing means 20, the developing sleeve rotating means 2A and 4A, and the control for imparting charging conditions are each controlled simultaneously and automatically. Ru. Therefore, even if the image forming state of the reader printer LP becomes defective and the cause is no force, the image forming state can be restored to a good state by simply performing a simple operation. Furthermore, in this embodiment, drum drying and toner replenishment are performed together, so if another developer is mixed in the selected developing device, the mixed developer will be removed one after another during drum drying. It is developed and contamination is removed. In this embodiment, the recovery measures are set to be performed only on the selected developing device, but the recovery measures may be set to be performed on all developing devices regardless of the selection. . Further, the timing for terminating step 200 and step 300 (recovery processing) is determined by a predetermined switch operation,
A means for detecting humidity is provided on the photosensitive drum D, and when it detects that the drum is dry, or after a period of time corresponding to the previous history before an unselected developing device enters the recovery process (the more times it has been used, , longer time) is suitable for children. Furthermore, the timing for starting the recovery process may be set to automatically start after a predetermined number of consecutive development operations are performed using the same developing device. Effect> As can be understood from the above explanation, in the control device for an electrophotographic image forming machine according to the present invention, by simply performing a predetermined operation, the control means controls the photosensitive drum rotating means, the charging device, the erase lamp, and the toner. The replenishment means are each automatically controlled in operation. Therefore, even if the image forming state of the electrophotographic image forming machine becomes defective and the cause thereof is unknown, the image forming state can be restored to a good state by simply performing a simple operation.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of a reader printer to which a control device for an electrophotographic image forming machine according to the present invention is applied, and FIG. 2 is an explanatory diagram showing the main parts of the reader printer of FIG. 1.
3 is an explanatory diagram showing the toner replenishing means in the reader printer of FIG. 1, FIG. 4 is a system block diagram showing the main electrical configuration of the control device in the reader printer 2 of FIG. 5, 6, and 7 are flowcharts showing processing procedures performed by the CPU of the control device. 1 ・ Dispute ・ 2 ● ・ ・ 3 1 φ 4 ・ ◆ ● 2A, 4A・2B, 4B・ Control device, P-P developer, CPU, N-P developer, developing sleeve and its rotation means , Ear cutting shutter 5...Program ROM, 6, 8...Charging device (main charger, transfer charger), operation unit, ATDC sensor erase lamp, working RAM, photosensitive drum rotation means, toner supply means (ATDC sensor) 9. Toner supply screw TS, developer stirring screw DS), leader printer toner supply screw developer stirring screw photosensitive drum. 7 / 9 φ IO・ 1l・ 13φ 20・ LP TS DS D ・ Patent Applicant Minolta Camera Co., Ltd. Patent Attorney Seiichi Kuwai (and 1 other person) Figure 3

Claims (1)

[Claims] (1) A control device for an electrophotographic image forming machine that controls the electrophotographic image forming machine, the device comprising: a photosensitive drum rotating means for rotating a photosensitive drum; a charging device for charging the photosensitive drum; and a charged photosensitive drum. an erase lamp for eliminating static electricity; a toner replenishing means for replenishing the developing device with toner upon detecting that the toner to carrier mixing ratio has become less than a desired value; and a photosensitive drum rotating means in response to a predetermined operation; charging device,
A control device for an electrophotographic image forming machine, comprising: control means for controlling the operations of an erase lamp and a toner supply means, respectively.