JP2001083843A - Image forming device - Google Patents

Abstract

(57) [Summary] [Problem] To quickly detect an abnormality at the time of pre-run without paper passing, prevent a large amount of developer from adhering to the photoreceptor, prevent contamination of peripheral devices and the inside of a copying machine main body, or This prevents the carrier from damaging the cleaning blade and the photoconductor, improves the reliability of the pre-run operation, and ensures the initial setting of the auto toner sensor. A reflectance sensor (18) for detecting the reflectance of the surface of a photoconductor (11) is provided in front of a cleaning device (20) of a cleaner unit (27). At the time of the pre-run for driving the photoconductor 11 and the developing unit 14 without passing the paper, a large amount of the developer adheres to the surface of the photoconductor 11 due to an abnormality, and the reflectance sensor 18 determines that the surface reflectance of the photoconductor 11 is a predetermined value. If it is detected that the value is out of the range, the photosensitive member 11 and the developing device 1
4 is stopped and a warning is issued to prevent further developer adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to prevent a large amount of developer and toner from adhering to a photoreceptor due to an abnormality during a pre-run operation without paper passing in an image forming apparatus such as a printer or an electrophotographic apparatus. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art In a developing device for developing with a so-called two-component developer composed of a toner and a carrier in an image forming apparatus such as a printer or an electrophotographic apparatus, an automatic toner sensor detects the toner concentration in the developing device. The toner is replenished according to the detection result, and a desired development density is maintained. The auto toner sensor detects the toner concentration reliably and stably. When the image forming apparatus main body is set up, when the developer is replaced for the first time, for example, or when the developer is replaced with a new one, the developer is used. Conventionally, in order to make the developing device work well, and to reset the initial value of the detection value of the auto toner sensor, a so-called pre-run, in which the photoconductor is rotated without paper passing and the developing device is operated, was conventionally performed. . That is, a new developer is stirred in the developing container to start charging the toner in the developer, and the photoconductor is rotated for several minutes,
The detection value of the auto toner sensor at that time was set as an initial value.

In an image forming apparatus, when the power is turned on after the main power of the image forming apparatus is turned off for a certain period of time or longer (for example, when the power is turned on in the morning or when a paper jam in the apparatus is cleared). For example, when the front cover is opened and closed, the above-described pre-run in which the photoconductor is rotated and the developing device is operated without passing the paper is conventionally performed.

[0004]

However, in the above-mentioned conventional image forming apparatus, during the pre-run without paper passing, the charging member is damaged, the charging transformer / developing bias transformer is malfunctioning, or the charging member is not mounted. If an abnormality such as forgetting is made, an excessive amount of toner or developer will adhere to the photoconductor during development. For this reason, there is a problem that a large amount of toner adhered to the photoreceptor contaminates around the photoreceptor and the inside of the image forming apparatus main body, and a carrier in the developer damages the photoreceptor and a photoreceptor contact member such as a cleaning blade. Was. Moreover, since no paper is passed, it is not possible to visually check the transferred paper for abnormalities, delay in finding abnormalities, and further damage due to a larger amount of toner or developer adhering to the photoconductor. There was a problem of increasing the size.

In view of the above, the present invention has been made to solve the above-mentioned problem. In the event that an abnormality occurs in a charging device, a developing bias, or the like during a pre-run operation without paper passing, the abnormality is immediately detected without visual observation to detect the photosensitive member. Prevents a large amount of toner or developer from adhering to the image forming apparatus, without causing contamination in the image forming apparatus main body and damage to the photoconductor and the photoconductor contact member.
It is an object to provide a highly reliable image forming apparatus.

[0006]

In order to solve the above-mentioned problems, the present invention provides a drum-shaped image carrier, charging means for uniformly charging the image carrier according to rotation of the image carrier, and Latent image forming means for forming an electrostatic latent image on the image carrier uniformly charged by the charging means, and developing means for applying toner to the image carrier after passing through the latent image forming means position; Transfer means for transferring the toner on the image carrier to the transfer object, cleaning means for removing residual toner on the image carrier after passing through the transfer means position, and reaching the cleaning means from the developing means. Detecting means for detecting the reflectance of the surface of the image carrier provided between the image carrier and the image carrier without the electrostatic latent image forming operation by the latent image forming means and the transfer operation by the transfer means. Activating the developing means During that, when said detecting means detects the detection result of the outside of the predetermined value is for stopping the rotation of the image bearing member.

According to another aspect of the present invention, there is provided a drum-shaped image carrier, charging means for uniformly charging the image carrier in accordance with the rotation of the image carrier, and uniform charging by the charging means. Latent image forming means for forming an electrostatic latent image on the charged image carrier, developing means for applying toner to the image carrier after passing through the latent image forming means, and the image carrier A transfer unit for transferring the toner on the transfer member, a cleaning unit for removing residual toner on the image carrier after passing through the transfer unit, and a transfer unit provided between the developing unit and the cleaning unit. Detecting means for detecting the reflectance of the surface of the image carrier, and operating the image carrier and the developing means without the electrostatic latent image forming operation by the latent image forming means and the transfer operation by the transfer means. While doing When the knowledge device detects a detection result of the outside of the predetermined value, and generates a warning to stop the rotation of the image bearing member.

According to another aspect of the present invention, there is provided a drum-shaped image carrier, charging means for uniformly charging the image carrier in accordance with rotation of the image carrier, and uniform charging by the charging means. Latent image forming means for forming an electrostatic latent image on the charged image carrier, developing means for applying toner to the image carrier after passing through the latent image forming means, and the image carrier Transfer means for transferring the upper toner to the transfer medium, cleaning means for removing residual toner on the image carrier after passing through the transfer means position, provided between the developing means and the cleaning means, A reference pattern detecting unit for detecting a reflectance of a reference pattern formed on the image carrier without a transfer operation by the transfer unit, and an electrostatic latent image forming operation by the latent image forming unit; By transfer means When the reference pattern detection unit detects a detection result outside a predetermined value range while the image carrier and the developing unit are operated without a transfer operation, the rotation of the image carrier is stopped. Things.

According to another aspect of the present invention, there is provided a drum-shaped image carrier, charging means for uniformly charging the image carrier in accordance with rotation of the image carrier, and uniform charging by the charging means. Latent image forming means for forming an electrostatic latent image on the charged image carrier, developing means for applying toner to the image carrier after passing through the latent image forming means, and the image carrier Transfer means for transferring the upper toner to the transfer medium, cleaning means for removing residual toner on the image carrier after passing through the transfer means position, provided between the developing means and the cleaning means, A reference pattern detecting unit for detecting a reflectance of a reference pattern formed on the image carrier without a transfer operation by the transfer unit, and an electrostatic latent image forming operation by the latent image forming unit; By transfer means While the image carrier and the developing device are operating without a transfer operation, when the reference pattern detecting unit detects a detection result outside a predetermined value range, the rotation of the image carrier is stopped. Warning.

According to the present invention, the reflectivity of the surface of the image carrier is detected by the detecting means provided between the developing unit and the cleaning means during the pre-run operation without paper passing, and the image carrier is extremely damaged. If the toner or the developer is attached and the detection result by the detection unit is out of the predetermined range, the rotation of the image carrier is stopped immediately, thereby contaminating the inside of the image forming apparatus main body, the photoconductor, and the like. An object of the present invention is to provide a highly reliable image forming apparatus which can prevent damage to a photosensitive member and prevent further toner and developer from adhering to an image carrier.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS. FIG. 1 is a schematic configuration diagram showing an image forming section 10 of a copying machine (not shown) which is an image forming apparatus, and a photosensitive member 11 serving as a charging unit is provided around a drum-shaped photosensitive member 11 which is an image carrier. A charger 12 for uniformly charging to -650 V; an exposure device (not shown) serving as a latent image forming means for converting image information into optical information, and scanning and exposing the photoreceptor 11 to form an electrostatic latent image; An exposure unit 13, a developing unit 14 as a developing unit for applying toner to the photoreceptor, a transfer belt 16a as a transfer unit for transferring the toner image on the photoreceptor 11 to sheet paper or the like as a transfer target, and a transfer roller 1
A transfer device 16 having a photoreceptor 6b, a peeling claw 17, and a reflectance sensor 1 serving as a detecting unit for detecting the reflectance of the surface of the photoconductor 11
8. The cleaning device 20 and the static eliminator 21 are sequentially arranged along the rotation direction.

Reference numeral 22 denotes a registration roller which conveys a sheet supplied from a sheet cassette unit or a sheet tray (not shown) toward the transfer device 16 in synchronization with a toner image formed on the photoconductor 11. It is.

The developing unit 14 contains a two-component developer composed of a toner and a carrier in a housing 14a, and a developing bias of -450 V is applied to the upper and lower developing rollers 23a and 23b by a bias transformer (not shown). . Further, first and second mixing augers 24a and 24b for stirring and transporting the two-component developer are provided in the housing 14a,
Below the first mixing auger, an automatic toner sensor 26 for detecting the toner concentration in the developer is provided.

The peeling claw 17, the reflectance sensor 18, and the cleaning device 20 are formed integrally with a cleaner unit 27 as shown in FIG. The reflectance sensor 18 including the light emitting unit 18a and the light receiving unit 18b is installed between the peeling claws 17 of the cleaner unit 27. The reflectivity sensor 18 is used for the photosensitive member 11 without passing the paper.
It is used for image quality maintenance control that detects the reflectance of the toner image of the reference pattern formed thereon, controls each process condition so that the detection result falls within a desired range, and obtains a constant image quality. Detects the reflectance of the photoconductor 11 during the pre-run, in which the photoconductor 11 and the developing rollers 23a and 23b are rotated without passing the paper, and detects the abnormality of the charging charger 12 and the developing bias. Used for

The cleaning device 20 has a main blade 28 above the case 20a and a recovery blade 30 below the case 20a. Reference numeral 31 denotes a toner recovery auger that conveys the residual toner recovered from the bottom surface of the case 20a to one side of the case 20a, and reference numeral 32 denotes a fur brush that removes the residual toner on the photoconductor 11.

FIG. 3 is a block diagram showing a control system 35 for controlling the pre-run of the image forming section 10. A control device 36 for controlling the main body of the copying machine has an output interface 37.
And various drivers 3 for the photoconductor 11 and the developing device 14
8, a high-pressure generating section 40 and a display section 41 for displaying a warning are connected. Further, an input key 43, a reflectance sensor 18, an auto toner sensor 26, and other switches / sensors 44 are connected to the controller 36 via an input interface 42.

Next, the operation during the pre-run will be described with reference to the flowchart shown in FIG. When the power of the copying machine (not shown) is turned on at the start of step 100, the process proceeds to either step 101 or step 102. In step 101, a pre-run 1 for initializing the auto-toner sensor 26 is performed at the time of initial setup such as when the copying machine is installed or when the developing device is replaced, or immediately after the developer is replaced with a new one. The pre-run 2 is performed when the power is turned on after the main power of the image forming apparatus main body is cut off for a certain period of time or longer (for example, when the power is turned on in the morning or after a paper jam in the copying machine main body).

In any of the pre-run 1 and the pre-run 2, the process proceeds to step 103 and the photosensitive member 11 and the developing device 1
Rotate 4. At this time, if the charging charger 12 and the developing bias are normal, the photosensitive member 11 is uniformly rotated by −65 by the charging charger 12 according to the rotation in the direction of the arrow x.
The developer reaches the developing device 14 while being charged to 0V. Developing device 1
In No. 4, since the developing bias is -450 V, the photoconductor 11 reaches the reflection sensor 18 without toner adhesion from the upper and lower developing rollers 23a and 23b to the photoconductor 11 side.

On the other hand, if the charging charger 12 is abnormal in step 103, the photosensitive member 11 is not charged by the charging charger 12 during rotation, and reaches the developing device 14 with its surface potential being almost 0V. . Therefore, -45
Upper and lower developing rollers 23 to which a developing bias of 0 V is applied
The toner adheres to the entire surface of the photoconductor 11 from a and 23b and reaches the reflection sensor 18 in this state.

Thereafter, as shown in step 104, the reflectance sensor 18 detects the reflectance of the surface of the photoreceptor 11, and proceeds to step 106. That is, when the charging charger 12 and the developing bias are normal and the toner is not attached to the photoconductor 11, the reflectance sensor 18 detects that the reflectance from the surface of the photoconductor 11 is a predetermined value (the toner is slightly applied to the surface of the photoconductor 11). And the carrier is attached), the process proceeds to step 107, and the pre-run is continued for a predetermined time thereafter. On the other hand, if the charging charger 12 and / or the developing bias is abnormal and toner adheres to the entire surface of the photoconductor 11, the reflectance sensor 18 has a reflectance from the surface of the photoconductor 11 outside a predetermined value range. The control device 36 determines that the photosensitive member 1
The rotation of the developing unit 1 and the developing unit 14 is stopped immediately, and a warning indicating an abnormality is displayed on the display unit 41.

In this way, in the event of an abnormality, although toner adheres to the entire surface of the photoreceptor 11 until it reaches the reflectance sensor 18 from the developing device 14, further large amount of toner is prevented from adhering.

The image forming unit 10 and the control system 35 constructed as described above are employed in a digital copying machine Pre-Mage 651 manufactured by Toshiba Tec Corporation, and a switch is provided in a power supply unit (not shown) of the charging charger 12 so that charging can be cut off. Then, the charger 12 was switched between a normal state and an abnormal state, and a pre-run operation for initial setting of the auto toner sensor 26 of the developing device 14 was performed.

As a result, when power is supplied to the charging charger 12 and pre-run is performed, the auto toner sensor 26 can be initialized well. On the other hand, when the power supply to the charging charger 12 is cut off and the pre-run is performed, the photosensitive member 11 is stopped immediately when the toner adhering portion of the photosensitive member 11 reaches the reflectance sensor 18. Thereby, the photoconductor 11
The portion where the toner adheres to the entire surface is the cleaning device 20.
Does not reach the main blade 28, and damage to the photoconductor 11 and the main blade 28 due to the sliding contact can be prevented. In the period from the developing device 14 to the reflectance sensor 18, toner adheres to the entire surface of the photoconductor 11, but the amount of the toner adhered is not so large as to cause toner scattering in the copying machine main body. No contamination of peripheral equipment was observed.

With such a configuration, in the pre-run 1 for initializing the auto toner sensor 26 or in the pre-run 2 after the power is turned on after the main power is cut off for a certain period of time, the charging charger 12 and the developing device 14 are abnormal. When a large amount of toner or developer adheres to the photoconductor 11, the reflectance sensor 18 immediately detects that the reflectance is out of the predetermined value range, and the control device 36 controls the photoconductor 11
In addition, the rotation of the developing device 14 can be stopped immediately, and a warning indicating an abnormality can be displayed on the display unit 41. Therefore, a large amount of the developer adhered on the surface of the photoconductor 11 does not reach the main blade 28 of the cleaning device 20, and the photoconductor 11
And the main blade 28 can be prevented from being damaged. Also, regardless of the occurrence of an abnormality, a large amount of toner or the like adhered to the photoconductor 11 can be significantly suppressed as compared with the related art, and the contamination of the peripheral device of the photoconductor 11 and the contamination in the copying machine main body due to the scattering of the toner and the like can be prevented. Prevention and improved reliability during pre-run.

The present invention is not limited to the above-described embodiment, but can be changed without departing from the spirit of the present invention. It does not have to be shared with the reference pattern detecting means for detecting the reference pattern, and the installation position is also
After the development, it is optional as long as it reaches the cleaning means. The warning at the time of occurrence of an abnormality is not limited to a sound, a lamp, or the like.

[0026]

As described above, according to the present invention, when a large amount of toner or developer adheres to the image carrier during the pre-run without paper passing, the surface of the image carrier becomes abnormal. This is immediately detected by the detection means for detecting the image carrier, and the image carrier and the developing means are immediately stopped to prevent further adhesion of the developer and the like. Therefore, a large amount of developer or the like adhering to the surface of the image carrier does not adhere to peripheral devices and cause contamination of the device, or toner scattering does not cause staining of the main body of the copying machine. In this case, there is no possibility that the carrier may damage the image carrier or the cleaning blade, and the reliability during the pre-run can be improved. In the developing means, the initial value of the automatic toner sensor can be reliably set without causing contamination of the apparatus by the developer or the like.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an image forming unit of a copying machine according to an embodiment of the present invention.

FIG. 2 is a schematic front view showing a cleaner unit according to the embodiment of the present invention.

FIG. 3 is a block diagram illustrating a control system for a pre-run operation according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation during a pre-run according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Image forming part 11 ... Photoconductor 12 ... Charging charger 13 ... Exposure part 14 ... Developing device 16 ... Transfer device 18 ... Reflectivity sensor 20 ... Cleaning device 23a, 23b ... Upper and lower developing roller 26 ... Auto toner sensor 27 ... Cleaner unit 28 ... Main blade

Claims (8)

[Claims] 1. A drum-shaped image carrier, charging means for uniformly charging the image carrier in accordance with rotation of the image carrier, and a charging means for charging the image carrier uniformly by the charging means Latent image forming means for forming an electrostatic latent image; developing means for applying toner to the image carrier after passing through the position of the latent image forming means; and transferring the toner on the image carrier to a transfer object A transfer unit; a cleaning unit that removes residual toner on the image carrier after passing through the transfer unit position; and a reflectance unit that is provided between the developing unit and the cleaning unit to detect a reflectance of the surface of the image carrier. A detecting unit, wherein the detecting unit is operated while the image carrier and the developing unit are operated without an electrostatic latent image forming operation by the latent image forming unit and a transfer operation by the transfer unit. Detection of out of range of specified value Upon detecting a result, the image forming apparatus characterized by stopping the rotation of the image bearing member. 2. A drum-shaped image carrier, a charging means for uniformly charging the image carrier according to the rotation of the image carrier, and a charging means for uniformly charging the image carrier by the charging means. Latent image forming means for forming an electrostatic latent image; developing means for applying toner to the image carrier after passing through the position of the latent image forming means; and transferring the toner on the image carrier to a transfer object A transfer unit; a cleaning unit that removes residual toner on the image carrier after passing through the transfer unit position; and a reflectance unit that is provided between the developing unit and the cleaning unit to detect a reflectance of the surface of the image carrier. A detecting unit, wherein the detecting unit is operated while the image carrier and the developing unit are operated without an electrostatic latent image forming operation by the latent image forming unit and a transfer operation by the transfer unit. Detection of out of range of specified value Upon detecting a result, the image forming apparatus characterized by generating a warning to stop the rotation of the image bearing member. 3. A pre-run time period during which the image carrier and the developing unit are operated without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit. The image forming apparatus according to claim 1, wherein: 4. The automatic toner of the developing unit during the operation of the image carrier and the developing unit without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit. 3. The image forming apparatus according to claim 1, wherein a pre-run is performed for initial setting of the sensor. 5. A drum-shaped image carrier, a charging means for uniformly charging the image carrier according to the rotation of the image carrier, and a charging means for uniformly charging the image carrier by the charging means. Latent image forming means for forming an electrostatic latent image; developing means for applying toner to the image carrier after passing through the position of the latent image forming means; and transferring the toner on the image carrier to a transfer object A transfer unit, a cleaning unit that removes residual toner on the image carrier after passing through the transfer unit position, and a transfer unit that is provided between the developing unit and the cleaning unit and that does not involve a transfer operation by the transfer unit. A reference pattern detecting unit for detecting a reflectance of a reference pattern formed on the image carrier, wherein the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit are not performed. Image bearer While operating body and the developing unit, when the reference pattern detection means detects the detection result of the outside of the predetermined value, the image forming apparatus characterized by stopping the rotation of the image bearing member. 6. A drum-shaped image carrier, charging means for uniformly charging the image carrier in accordance with rotation of the image carrier, and a charging means for uniformly charging the image carrier by the charging means. Latent image forming means for forming an electrostatic latent image; developing means for applying toner to the image carrier after passing through the position of the latent image forming means; and transferring the toner on the image carrier to a transfer object A transfer unit, a cleaning unit that removes residual toner on the image carrier after passing through the transfer unit position, and a transfer unit that is provided between the developing unit and the cleaning unit and that does not involve a transfer operation by the transfer unit. A reference pattern detecting unit for detecting a reflectance of a reference pattern formed on the image carrier, wherein the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit are not performed. Image bearing When the reference pattern detection unit detects a detection result outside a predetermined value range while the body and the developing unit are operating, the rotation of the image carrier is stopped and a warning is generated. Image forming apparatus. 7. A pre-run time period during which the image carrier and the developing unit are operated without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit. The image forming apparatus according to claim 5, wherein: 8. The automatic toner of the developing unit during the operation of the image carrier and the developing unit without the electrostatic latent image forming operation by the latent image forming unit and the transfer operation by the transfer unit. 7. The image forming apparatus according to claim 5, wherein a pre-run is performed for initial setting of the sensor.