JPH0414059A - Method and device for preventing variation of background potential of photosensitive body for image forming device - Google Patents

Abstract

PURPOSE:To make image quality stable by correcting light quantity for illumination and exposure in accordance with a time from the stop time of a photosensitive body and from starting forming an image. CONSTITUTION:A CPU 11 calculates target light quantity for a lamp 2 according to magnification and density, etc. Next, the light quantity from a reference reflector 3 is measured by an AE sensor 6 and when it is different from the target light quantity, they are caused to agree with each other by correcting the impressed voltage from a lamp power source 9. The CPU 11 measures the unlighted time of the lamp 2 by referring to a timer 12 at any time, and the stop time of the photosensitive body 1 is measured corresponding to the unlighted time. A corrected value corresponding to the stop time of the photosensitive body 1 is read out from a storage device so as to correct the impressed voltage on the lamp 2. Then, the lighting time of the lamp 2 with the corrected voltage is measured, and the lamp 2 is lighted with the corrected voltage until the measured time becomes the target lighting time with the voltage. The above operation is repeated until the corrected value becomes zero, and then the lamp is lighted with the decided voltage. By controlling the impressed voltage and controlling the illuminating light quantity so that the variation of a background potential may be prevented, the image quality is made stable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method of illuminating an original to form an electrostatic latent image corresponding to the original on a photoreceptor, and developing the electrostatic latent image. In an image forming apparatus that transfers a toner image onto paper or the like, the background potential of the photoreceptor fluctuates due to the history of the photoreceptor and illumination lamp, especially at the beginning of the image forming operation, making the quality of the image formed unstable. This article relates to a method for preventing this from occurring and a device for preventing it.

[Conventional technology]

Conventionally, in electrophotographic copying machines and the like that develop an electrostatic latent image formed on a photoreceptor and transfer the toner image, the sensitivity of the photoreceptor and the characteristics of the lamp are unstable at the beginning of the copying operation. It is known to wait for these characteristics to stabilize before starting a copying operation. In addition, in order to eliminate the above-mentioned instability in the sensitivity of the photoconductor, before the start of the copying operation, the photoconductor is subjected to optical fatigue as a pre-cycle, and charging and photostatic discharge are applied to stabilize the charging characteristics and sensitivity. It is also known that the copying operation is started after the copying process has been completed.

[11 that the invention attempts to solve! However, the sensitivity of the photoconductor and the characteristics of the lamp at the beginning of copying change depending on the history of the photoconductor and lamp before the start of copying, especially the rest time of the photoconductor and lamp, so this cannot be corrected. Conventionally, it has not been possible to quickly start up and start a stable copying operation.

The present invention was made in view of this situation, and
The purpose of this is to correct the voltage applied to the lamp according to the rest time of the photoreceptor, the lamp, and the time since the start of copying, in particular to prevent fluctuations in the background potential of the photoreceptor at the beginning of copying, and to To provide a method and an apparatus for eliminating the waiting time for stabilizing the start-up of a computer and shortening the time (FCOT) until the first copy is completed.

[A means to solve problems]

A method for preventing background potential fluctuation of a photoreceptor in a first image forming apparatus of the present invention that achieves the above object is to illuminate an original to form an electrostatic latent image corresponding to the image on the photoreceptor. In an image forming apparatus that transfers a toner image obtained by developing an image onto a sheet of paper, etc., the background potential of the photoconductor is measured based on the change in the sensitivity of the photoconductor at the beginning of the image forming operation. This method is characterized by correcting the amount of illumination light or the amount of exposure light depending on the rest time of the body and the time from the start of the image forming operation.

Further, in the second method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention, an electrostatic latent image corresponding to the original is formed on the photoreceptor by illuminating the document, and the electrostatic latent image is developed. In an image forming apparatus that transfers a toner image obtained by image forming onto a sheet of paper, etc., fluctuations in the background potential of the photoreceptor due to changes in the amount of light emitted by the illumination light source at the beginning of the image forming operation are This method is characterized by correcting the voltage applied to the illumination light source according to the time, the lighting time before the stoppage, and the time from the start of lighting.

Furthermore, a third method for preventing background potential fluctuations of a photoreceptor in an image forming apparatus is to illuminate an original, form an electrostatic latent image corresponding to the original on the photoreceptor, and develop the electrostatic latent image. In an image forming apparatus that transfers a toner image onto paper or the like, the background potential of the photoconductor is measured based on changes in the sensitivity of the photoconductor and changes in the amount of light emitted by the illumination light source at the beginning of the image forming operation. The voltage applied to the illumination light source is corrected according to the rest time of the photoreceptor and the time from the start of image forming operation, the rest time before the illumination light source turns on, the lighting time before the rest, and the time from the start of lighting. This method is characterized in that it is prevented by:

Further, the device for preventing background potential fluctuation of the photoreceptor in the image forming apparatus implementing the first method of the present invention illuminates the document to form an electrostatic latent image corresponding to the image on the photoreceptor, and the electrostatic latent image is In an image forming apparatus that transfers a toner image obtained by developing a latent image onto paper or the like, exposure amount correction data is stored in accordance with the rest time of a photoreceptor before the start of image formation and the time from the start of image forming operation. means for measuring the rest time of the photoreceptor before the start of image formation, means for measuring the time from the start of image forming operation, and exposure amount correction data according to the time measured by the previous measuring means. and means for correcting the illumination light source or the exposure light amount using the exposure correction data read by the reading means.

A background potential fluctuation prevention device for a photoreceptor in an image forming apparatus that implements the second method of the present invention illuminates an original to form an electrostatic latent image corresponding thereto on the photoreceptor, and the electrostatic latent image In an image forming apparatus that transfers a toner image obtained by developing a toner image onto paper, etc., applied voltage correction data is stored in accordance with the downtime of the illumination light source before the start of lighting, the lighting time before the stoppage, and the time since the start of lighting. a means for measuring the pause time before the illumination light source turns on; a means for measuring the lighting time before the pause; a means for measuring the time from the start of the lighting; The present invention is characterized by comprising means for reading applied voltage correction data according to time, and means for correcting the voltage applied to the illumination light source based on the applied voltage correction data read by the reading means.

Further, a device for preventing background potential fluctuation of a photoreceptor in an image forming apparatus implementing the third method illuminates the document to form an electrostatic latent image corresponding thereto on the photoreceptor; In an image forming apparatus that transfers a toner image obtained by development onto a sheet of paper, etc., a first image forming apparatus that transfers a toner image obtained by development onto a sheet of paper, etc.
means for storing applied voltage correction data, and second applied voltage correction data corresponding to the pause time of the illumination light source before the start of lighting, the lighting time before stopping, and the time from the start of lighting;
A means for measuring a pause time before lighting an illumination light source, a means for measuring a lighting time before the lighting, a means for measuring a time from the start of lighting, and a means for measuring a pause time of a photoreceptor before starting image formation. means for reading first and second applied voltage correction data according to the time measured by each of the measuring means, with the origin of time measurement from the start of the image forming operation being regarded as the time when the illumination light source is turned on; and the reading means The present invention is characterized by comprising means for correcting the voltage applied to the illumination light source based on the first and second applied voltage correction data read out.

[Effect]

According to the first method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention and the apparatus for carrying out the method, it is possible to Since the amount of illumination light or the amount of exposure light is corrected, it is possible to prevent the background potential corresponding to the white background of the document from fluctuating due to sensitivity changes depending on the rest time of the photoreceptor and the time from the start of image forming operation. It is possible to prevent the formation of an image from having gaps, fogging of the white background, etc., and to prevent the initial image quality from becoming unstable.

According to the second method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention, and the device for carrying out the same, the downtime before lighting the illumination light source, the lighting time before the downtime, and the time from the start of lighting. Since the voltage applied to the illumination light source is corrected according to the time, the amount of light emitted by the illumination light source changes depending on the pause time before the illumination light source turns on, the lighting time before the pause, and the time from the start of lighting. can be maintained constant. Therefore, it is possible to prevent the background potential of the photoreceptor corresponding to the white background of the document from fluctuating due to changes in the light intensity of the illumination light source, which can prevent shading in the formed image, fogging of the white background, etc.
This can prevent the initial image quality from becoming unstable.

Furthermore, according to the third method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention and the apparatus for carrying out the method, the rest time of the photoreceptor before the start of image formation and the time from the start of the image forming operation are provided. Since the voltage applied to the illumination light source is corrected according to the pause time before lighting the illumination light source, the lighting time before the pause, and the time from the start of lighting, the photoconductor pause time and image formation can be adjusted. It is possible to prevent the background potential corresponding to the white background of the document from fluctuating due to the sensitivity change depending on the time from the start of operation, and also to prevent the background potential corresponding to the white background of the document from changing. By keeping the amount of light emitted from the illumination light source constant, which changes depending on the time from the start of lighting, it is possible to similarly prevent the background potential from fluctuating due to changes in the amount of light from the illumination light source, and to prevent the background potential from changing due to changes in the amount of light from the illumination light source. It is possible to prevent image distortion, background fogging, etc., and to prevent the initial image quality from becoming unstable.

〔Example〕

The sensitivity of a photoreceptor that forms an electrostatic latent image is schematically shown in FIG. That is, the surface potential of the photoreceptor is plotted on the vertical axis and the exposure dose is plotted on the horizontal axis, and a curve representing the change in surface potential with respect to an increase in the exposure dose represents the sensitivity. This sensitivity curve becomes a downward-sloping curve as shown in the figure. Among them, the surface potential when the exposure amount is zero is called the dark area potential VlllDp, which corresponds to the black area of the document, and the potential at the maximum exposure amount E is the background potential or the bright area potential VlllDp.
B and G are the electric potentials corresponding to the white parts of the original, and the electric potential when the exposure amount is increased and the sensitivity is saturated is called the residual electric potential V up, which is the electric potential when the static electricity is removed. It is electric potential. By the way, if a photoreceptor is left at rest without being charged or neutralized, its light attenuation curve generally changes in the A direction or B direction in the figure, and whether it changes in the incoming direction or in the B direction. depends on the type of photoreceptor. Also, depending on the type of photoreceptor, the bright area potential VmM changes due to a change in the dark area potential V0° due to the dark resistance of the photoreceptor. There are things that change. When illustrated, it looks like the schematic diagram in FIG. In this case as well, whether the change occurs in the A direction or the B direction depends on the type of photoreceptor. Incidentally, the extent to which the sensitivity changes in the in direction or the B direction depends on the above-mentioned pause time. When you start using such a photoreceptor again, the sensitivity changes in the direction opposite to the in direction or B direction in Figures 1 and 2, and after a certain amount of time, the sensitivity changes as shown by the solid line in the figure. becomes stable. If the sensitivity changes with the pause time in this way, if the exposure is started from the beginning with the exposure amount E when the sensitivity finally stabilizes, the background potential VIG will change to C or D in the figure, as is clear from the figure. Put it away. When the background potential changes in this way,
Not only will the copied image become opaque or the white background may become foggy, which will impair the quality of the copied image, but the background potential will change depending on the time from the start of copying, making the original image quality unstable. Become. Therefore, the image quality at the beginning of copying may deteriorate, or the density of the image set at the beginning of copying may change. Therefore, in the present invention,
In order to compensate for the above sensitivity change at the beginning of copying until the sensitivity stabilizes, the exposure amount of the white background is corrected according to the rest time of the photoreceptor and according to the time from the start of copying. do.

For example, in the case of an organic photoreceptor called OPC Red whose cross-sectional structure is shown in FIG.
Sensitivity changes in the direction of the figure. Therefore, the background potential is kept constant V□. In order to achieve this, the initial exposure amount must be corrected to E', which is less than E, in FIG. Since the sensitivity approaches the solid line as time passes from the start of copying, the exposure amount must approach E as time passes. Moreover, the longer the pause time, the smaller the initial exposure amount E' becomes.

In the case of the above photoreceptor ○PC Red, the rest time Tr.

1. The table shown in FIG. 5 shows the exposure correction amount according to the time Toi+ from the start of copying. Numbers in this table represent percentages. For example, the pause time before copying is 3.
In 20 seconds, a correction of 15% is performed when 5 seconds have elapsed from the start of rotation of the photoreceptor. In other words, if the exposure amount when the sensitivity of the photoreceptor is stabilized is E, the exposure amount during this time is (
100-5)/100XE=0.95E, the background potential is kept at a constant value V0G. To achieve this, the amount of light emitted from the lamp that illuminates the original to be copied may be adjusted to the above ratio. A block diagram of an example of a device for this purpose is shown in FIG. 6, and a flow chart of the control of the device is shown in FIG.

FIG. 6 shows a schematic configuration of a background potential fluctuation prevention device for a photoreceptor according to an embodiment of the present invention. An image forming apparatus to which this device is applied includes a photoreceptor 1, a lamp 2 that illuminates an original 4, and a lens 5 that projects an image of the original 4 onto the photoreceptor 1.
, a fixing device 7 that heats and fixes the toner image transferred from the photoreceptor 1 onto the paper, a lamp power source 9 for the lamp 2, a main board 10 that controls the image forming apparatus, etc., but includes a charger, a fixing device, A transfer device, a cleaning device, etc. are not shown. The background potential fluctuation prevention device of the present invention includes:
A reference reflection plate 3 is placed in front of a document 4 being scanned in the direction of the arrow in the figure, and the amount of reflected light is detected by an AE sensor 6 and the signal is sent to a main board 10. The main board 10 controls the voltage to be applied to the lamp 2 via the lamp power supply 9, and also monitors the voltage applied to the lamp power supply 9. Further, the main board 10 has a temperature sensor 8 disposed in the fixing device 7 to monitor its warm-up time. The main board 10 is a CP equipped with a storage device.
Equipped with UI 1 and timer 12, CPLill refers to timer 12! While straining, various times are measured. Further, the table shown in FIG. 5 is stored in the storage device. Now, with such a device, CPU II
The voltage to be applied to the lamp 2 is controlled according to the flow shown in FIG. That is, since the target light amount of the lamp 2 varies depending on the selected state of the image forming apparatus, such as magnification, density, etc., the target light amount is first calculated in step (2). Then, in step ■, lamp 2
is turned on and the light t from the reference reflector 3 is measured by the AE sensor 6. It is determined in step (2) whether this light amount matches the target light amount calculated in step (2), and if it does not match, the applied voltage is corrected in step (2).
Return to step ■, repeat steps ■～■ again,
Adjust the voltage applied to the lamp 2 to match the target light amount calculated in step (3). When this voltage matches the target light amount, the target voltage to be applied to the lamp 2 is determined in step 0. The amount of illumination light from the lamp corresponding to this voltage corresponds to the amount of exposure shown in FIG. By the way, C.P.
UII uses a constant timer 12 in addition to the main flow above.
The OFF time (lighting time) before the lamp 2 is turned on is measured in step (2) while referring to the above.

In the present invention, attention is paid to the fact that this lamp OFF time corresponds to the rest time of the photoreceptor 1, and the rest time of the photoreceptor 1 is measured by this lamp OFF time. Of course, the rest time of the photoreceptor 1 may be measured by time or the like.

In this embodiment, the timer is not operating when the power is turned off and then turned on again (initial time). (The relationship between the warm-up time and the rest time of the photoreceptor 1 is measured in advance and stored in a storage device.) Note that in the case of a configuration in which control devices such as the CPU 1 and the timer 12 are operated by batteries, and the CPU 1 and the timer 12 do not stop even when the power is turned off, the rest time of the photoconductor 1 described above is 7
It is not necessary to make any inferences from the warm-up time. Now, after determining the target voltage to be applied to the lamp 2 in step [F], in step (2), a correction value corresponding to the lamp OFF time (photoreceptor rest time) measured in step (2) is stored in the storage device. The table as shown in FIG. 5 is read out, and the voltage applied to the lamp 2 is corrected based on the corrected value. Next, in step 1, the lamp lighting time with the corrected voltage is measured, and step
and ■, that time is the target lighting time at that voltage (
For example, if the photoreceptor rest time T rest is 30 to 60 seconds, the lamp 2 is lit with the corrected voltage until -5 continues for 2 seconds. After that, return to step ■, read the next corrected voltage value from the table, and use this corrected voltage value to correct the voltage applied to lamp 2 (-4 for 2 seconds in the above case). Light the lamp for the required time. Repeat the above cycle until the correction value becomes zero (17 seconds in the above example),
Thereafter, the lamp 2 is turned on at the voltage determined in step (2). As mentioned above, the amount of illumination light is controlled by controlling the voltage applied to the lamp, which is predetermined according to the rest time of the photoreceptor and the time from the start of copying, and the amount of exposure from the white background of the document is corrected. , it is possible to prevent fluctuations in background potential due to changes in sensitivity of the photoreceptor at the initial stage of copying. Note that in the above, the exposure amount is corrected by adjusting the amount of light emitted from the lamp that illuminates the document, but this is not limited to this. It may also be done by.

Incidentally, when an incandescent lamp such as a halogen lamp is turned on by applying a constant voltage, the amount of light emitted changes with a certain tendency in the initial stage of lighting. The reason for this is that the resistance of the filament increases as the temperature rises, and the power consumption in the filament is 2/(resistance), so as the resistance increases from the initial stage of lighting, the amount of light emitted decreases. It is thought that this is because of this. Figure 8 shows a rating of 75V-3 as an example.
This shows the results of measuring the change in the relative amount of light emitted when the voltage shown in the figure is applied to a 50W halogen lamp.At any voltage, the amount of light emitted gradually decreases from the time the lamp is turned on, and becomes constant after 12 to 13 seconds. Stable at light intensity. Next, for the same lamp, when the lamp is left on for a predetermined period of time, turned off for a certain period of time, and then turned on again, the change in relative luminescence amount is measured, as shown in FIG. 9. In this case, the relative light emission amount also differs depending on the lamp lighting time before extinguishing, but in the figure, the lighting time is shown divided into 30 seconds or more and less than 30 seconds. As is clear from the figure, the amount of light emitted by the lamp changes depending on the pause (turn-off) time before lighting, the lighting time before stopping, and the time since lighting, especially at the start of lighting. Therefore, when forming a latent image using a lamp that changes the amount of emitted light, the background potential decreases at the start of copying, causing the copied image to skip even if there is no change in the sensitivity of the photoreceptor as described above. Problems such as this arise.

Therefore, in the present invention, in the same way as preventing changes in background potential due to changes in sensitivity, the voltage applied to the lamp is corrected at the start of copying to stabilize the amount of light emitted from the lamp. Try to prevent the ground potential from dropping. For this purpose, a device as shown in the block diagram of FIG. 6 is used, and control is performed according to a flowchart as shown in FIG. In this case, the CPU 11
A table as shown in FIG. 5 is stored in the storage device of , and this table stores the pause time before lighting the lamp, the lighting time before stopping, and the table according to the curve shown in FIG.
and a correction coefficient for the voltage applied to the lamp according to the time since lighting. To control the voltage to be applied to the lamp 2, first, in step 2 of FIG. and calculate the target voltage for the target light amount.

Then, in step (2), the lamp 2 is turned on and the applied voltage is measured. It is determined in step 2 whether this voltage matches the target voltage calculated in step ■, and if it does not match, the applied voltage is corrected in step ■, returns to step ■, and steps ■ to ■ are repeated again. , the voltage applied to the lamp 2 is made to match the target voltage calculated in step (2). When this voltage matches the target voltage, the target voltage to be applied to the lamp 2 is determined in step 0. The amount of illumination light from the lamp corresponding to this voltage corresponds to the amount of light when saturated in FIG. 8 or FIG. 9. By the way, the CPU II constantly refers to the timer 12 in addition to the above main flow,
The pause time (OFF time) before the lamp 2 is turned on is measured in step (3). It goes without saying that the downtime of the lamp 2 may be measured based on the downtime of other related devices. By the way, in this embodiment, the timer is not operating when the power is turned off and then turned on again (initial time), so the lamp 2 pause time is used as the fuser 7 warm-up time. (The relationship between the warm-up time and the down time of the lamp 2 is measured in advance and stored in a storage device.

〉. In addition, in the case of a configuration in which the control devices such as the CPU 1 and the timer 12 are operated by batteries so that the CPU 11 and the timer 12 do not stop even when the power is turned off, the rest time of the lamp 2 is It is not necessary to make any inferences from the warm-up time. Further, the CPU 1 constantly refers to the timer 12 in addition to the above-mentioned main 70-, and measures the lighting time of the lamp 2 before it is stopped in step (2). Now, after determining the target voltage to be applied to the lamp 2 in step (2), in step (2), the lamp applied voltage correction coefficient corresponding to the lamp rest time measured in step (2) and the lighting time before lamp rest measured in step (2) is calculated. A corrected voltage value is obtained by reading from the table in the storage device and multiplying the target voltage determined in step (2) by a correction coefficient, and the voltage applied to the lamp 2 is corrected using this corrected voltage value. Next 1. N, step ■
In steps 1 and 2, the lamp lighting time with the corrected voltage is measured, and in steps 1 and 2, the lamp 2 is turned on with the corrected voltage until the time reaches the target lighting time with that voltage. Thereafter, the process returns to step (2), reads the next corrected voltage value from the table, corrects the voltage applied to the lamp 2 using this corrected voltage value, and lights the lamp for the required time in steps (2) and (2). The above cycle is repeated until the corrected value becomes zero, and thereafter the lamp 2 is lit at the voltage determined in step 0. As mentioned above, by controlling the applied voltage of the lamp according to the pause time before lighting the lamp, the lighting time before stopping, and the time since lighting to keep the illumination light amount constant, it is possible to Fluctuations in the background potential due to changes in the amount of light emitted from the lamp can be prevented.

Furthermore, it is possible to simultaneously prevent background potential fluctuations based on changes in the sensitivity of the photoreceptor at the beginning of copying and prevention of background potential fluctuations based on changes in the amount of light emitted from the lamp at the beginning of lamp lighting. The flow for this purpose is the same as that shown in Fig. 10, but in Step 1 of Fig. 10, the table to be referred to for voltage correction is set according to the curve shown in Fig. A table consisting of lamp applied voltage correction coefficients according to the lighting time and time since lighting, and lamp applied voltage correction according to the photoreceptor rest time and time from the start of copying as shown in Fig. 5. Using a table consisting of coefficients,
The voltage will be corrected by multiplying both correction coefficients. The other processes are the same as those shown in FIG. 10, and by doing so, it is possible to prevent fluctuations in the background potential of the photoreceptor due to both of the above factors.

〔Effect of the invention〕

According to the first method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention and the apparatus for carrying out the method, it is possible to Since the amount of illumination light or the amount of exposure light is corrected, it is possible to prevent the background potential corresponding to the white background of the document from fluctuating due to sensitivity changes depending on the rest time of the photoreceptor and the time from the start of image forming operation. It is possible to prevent the formation of an image from having gaps, fogging of the white background, etc., and to prevent the initial image quality from becoming unstable.

According to the second method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention, and the device for carrying out the same, the downtime before lighting the illumination light source, the lighting time before the downtime, and the time from the start of lighting. Since the voltage applied to the illumination light source is corrected according to the time, the amount of light emitted by the illumination light source changes depending on the pause time before the illumination light source turns on, the lighting time before the pause, and the time from the start of lighting. can be maintained constant. Therefore, it is possible to prevent the background potential of the photoreceptor corresponding to the white background of the document from fluctuating due to changes in the light intensity of the illumination light source, which can prevent shading in the formed image, fogging of the white background, etc.
This can prevent the initial image quality from becoming unstable.

Furthermore, according to the third method of preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention and the apparatus for carrying out the method, the rest time of the photoreceptor before the start of image formation and the time from the start of the image forming operation are provided. Since the voltage applied to the illumination light source is corrected according to the pause time before lighting the illumination light source, the lighting time before the pause, and the time from the start of lighting, the photoconductor pause time and image formation can be adjusted. It is possible to prevent the background potential corresponding to the white background of the document from fluctuating due to the sensitivity change depending on the time from the start of operation, and also to prevent the background potential corresponding to the white background of the document from changing. By keeping the amount of light emitted from the illumination light source constant, which changes depending on the time from the start of lighting, it is possible to similarly prevent the background potential from fluctuating due to changes in the amount of light from the illumination light source, and to prevent the background potential from changing due to changes in the amount of light from the illumination light source. It is possible to prevent image distortion, background fogging, etc., and to prevent the initial image quality from becoming unstable.

Therefore, any method or apparatus of the present invention
It is possible to realize an image forming apparatus with quick start-up and stable characteristics.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the sensitivity of a photoreceptor that forms an electrostatic latent image and its change due to rest, and FIG. 2 is a diagram schematically showing that the bright area potential changes due to a change in dark potential. Figure 3 is a diagram showing the cross-sectional structure of the OPC red photoconductor, Figure 4 is a diagram similar to Figure 1 of the photoconductor in Figure 3, and Figure 5 is the rest time and copy start of the photoconductor in Figure 3. FIG. 6 is a block diagram of an example of a device for preventing background potential fluctuation of a photoreceptor in an image forming apparatus of the present invention, and FIG. A flowchart of the control of the device. Figure 8 shows the change in relative luminescence amount when a constant voltage is applied to the halogen lamp. Figure 9 shows the lamp being turned on for a predetermined period of time, turned off for a certain period of time, and then turned on again. FIG. 10 is a flowchart of another example of a background potential fluctuation prevention device for a photoreceptor. DESCRIPTION OF SYMBOLS 1...Photoreceptor, 2...Lamp, 3...Reference reflector, 4...Original, 5...Lens, 6...AE sensor, 7...Fixer, 8...・Temperature sensor, 9...
Lamp power supply, lO...main board, 11...CP
U, 12...Timer applicant Fuji Xerox Co., Ltd. agent Patent attorney Hiroshi Nirasawa (7 others) Figure 4 Drum surface light 1 (12 inches - Miriki) Figure 7 M] Figure ○ Main g vs. party amount (”/,) a Light amount (-/,)

Claims (7)

[Claims] (1) In an image forming apparatus that forms an electrostatic latent image on a photoreceptor, develops the electrostatic latent image, and transfers the obtained toner image to paper, etc., the sensitivity of the photoreceptor at the beginning of image forming operation. Fluctuations in the background potential of the photoreceptor due to changes are prevented by correcting the amount of illumination light or the amount of exposure light depending on the rest time of the photoreceptor before the start of image formation and the time from the start of image formation operation. A method for preventing background potential fluctuations of a photoreceptor in an image forming apparatus. (2) In an image forming apparatus that illuminates a document, forms a corresponding electrostatic latent image on a photoreceptor, develops the electrostatic latent image, and transfers the resulting toner image onto paper, etc. The fluctuation of the background potential of the photoconductor based on the change in the amount of light emitted by the illumination light source at the beginning of operation is determined by adjusting the background potential of the photoreceptor based on the change in the amount of light emitted by the illumination light source, depending on the pause time before lighting the illumination light source, the lighting time before the pause, and the time from the start of lighting. 1. A method for preventing background potential fluctuations of a photoreceptor in an image forming apparatus, the method comprising: correcting a voltage applied to a photoreceptor in an image forming apparatus. (3) Image forming in an image forming apparatus that illuminates a document to form a corresponding electrostatic latent image on a photoreceptor, develops the electrostatic latent image, and transfers the resulting toner image onto paper or the like. Changes in the background potential of the photoconductor due to changes in the sensitivity of the photoconductor at the beginning of operation and changes in the amount of light emitted by the illumination light source are
The voltage is applied to the illumination light source according to the rest time of the photoreceptor before the start of image formation and the time from the start of the image forming operation, the rest time before the lighting of the illumination light source, the lighting time before the stop, and the time from the start of lighting. 1. A method for preventing background potential fluctuations of a photoreceptor in an image forming apparatus, the method comprising: correcting a voltage applied to a background potential of a photoreceptor in an image forming apparatus. (4) In an image forming apparatus that forms an electrostatic latent image on a photoreceptor, develops the electrostatic latent image, and transfers the resulting toner image onto paper, etc., the rest time of the photoreceptor before starting image formation. and means for storing exposure amount correction data according to the time from the start of the image forming operation, means for measuring the rest time of the photoreceptor before the start of the surface image formation, and means for measuring the time from the start of the surface image forming operation. and means for reading out exposure correction data according to the time measured by both of the measuring means, and means for correcting the illumination light amount or the exposure light amount using the exposure correction data read by the reading means. A device for preventing background potential fluctuations of a photoreceptor in an image forming apparatus, characterized in that: (5) The means for measuring the rest time of the photoreceptor before the start of image formation comprises means for measuring the warm-up time of the fixing device and estimating the rest time from that time. A device for preventing background potential fluctuations of a photoreceptor in the image forming apparatus described above. (6) In an image forming device that illuminates a document to form a corresponding electrostatic latent image on a photoreceptor, develops the electrostatic latent image, and transfers the resulting toner image onto paper, etc., lighting starts. means for storing applied voltage correction data according to the down time of the previous illumination light source, the lighting time before the hiatus, and the time since the start of lighting; the means for measuring the down time before the lighting of the illumination light source; means for measuring lighting time; means for measuring time from the start of lighting; means for reading applied voltage correction data according to the time measured by each of the measuring means; and applied voltage read by the reading means. 1. A device for preventing background potential fluctuation of a photoreceptor in an image forming apparatus, comprising means for correcting a voltage applied to an illumination light source based on voltage correction data. (7) In an image forming apparatus that illuminates a document to form a corresponding electrostatic latent image on a photoconductor, develops the electrostatic latent image, and transfers the resulting toner image onto paper, etc. First applied voltage correction data according to the photoreceptor rest time before the start and the time from the start of the image forming operation, the rest time of the illumination light source before the start of lighting, the lighting time before the stop, and the time from the start of lighting means for storing second applied voltage correction data according to the lighting conditions; means for measuring a pause time before the illumination light source turns on; means for measuring the lighting time before the pause; and measuring time from the start of the lighting. and first and second measuring means corresponding to the time measured by each of the measuring means, assuming that the measurement origin of the rest time of the photoreceptor before the start of image formation and the time from the start of the image forming operation is the time when the illumination light source is turned on. It is characterized by comprising means for reading second applied voltage correction data, and means for correcting the voltage applied to the illumination light source based on the first and second applied voltage correction data read by the reading means. A device for preventing background potential fluctuations of a photoreceptor in an image forming apparatus. (8) The means for measuring the pause time before the illumination light source is turned on comprises means for measuring the warm-up time of the fixing device and estimating the pause time from that time. A device for preventing background potential fluctuations of a photoreceptor in the image forming apparatus described above.