JP6711636B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as an electrophotographic copying machine that forms an image on a recording medium using an electrophotographic image forming method, an electrophotographic printer (for example, a laser beam printer, an LED printer, etc.), or a facsimile machine. The present invention also relates to a process cartridge incorporated in the image forming apparatus.

In the electrophotographic image forming apparatus, from the viewpoint of ozone suppression, as a charging member for charging the photosensitive drum, a contact charging type charging roller for contacting and charging a conductive member with the photosensitive drum is widely used. There is. During charging by the charging roller, discharge is generated from the charging roller to the photosensitive drum. The amount of discharge from the end of the charging roller in the rotation axis direction (hereinafter, simply referred to as “end”) to the photosensitive drum is the amount of discharge from the center in the same direction (hereinafter, simply referred to as “central part”) to the photosensitive drum. More than. This is because in the vicinity of the end portion of the charging roller, in addition to the discharge near the contact portion between the charging roller and the photoconductor drum, the discharge is also performed from the end surface of the charging roller.

Here, the amount of abrasion on the surface of the photoconductor drum increases as the amount of discharge increases. Therefore, in the direction of the rotation axis of the photosensitive drum, the surface of the charging roller is more likely to be scraped near the end than at the center. Therefore, if the state of easy shaving continues near the end of the charging roller on the surface of the photosensitive drum, the film thickness of the photosensitive layer is locally shaving and the pressure resistance decreases. If the charging is performed in this state, the current concentrates on the locally shaved portion and an unchargeable area is formed around the portion, which may cause a leak image.

On the other hand, there has been proposed a method of suppressing local abrasion of the surface of the photosensitive drum near the end of the charging roller. For example, in Japanese Patent Application Laid-Open No. 2004-163242, a configuration is adopted in which the pre-exposure device shields the static elimination light emitted near the ends of the charging roller from the static elimination light emitted to the surface of the photosensitive drum. As a result, the static elimination light is not emitted in the vicinity of both ends of the charging roller, and when the photosensitive drum is recharged, the potential difference between the both ends of the charging roller and the photosensitive drums in the vicinity becomes small, and discharge is suppressed. Is possible.

JP, 2008-52207, A

In the image forming apparatus of the intermediate transfer system capable of forming a color image, when the image is primarily transferred to the intermediate transfer belt, an appropriate transfer voltage corresponding to the endurance variation of the resistance value of the primary transfer roller or the intermediate transfer belt and the environmental variation is applied. There is a control method to set. As this control method, the Active Transfer Voltage Control control method (hereinafter referred to as ATVC control) is widely known. In this ATVC control, first, several kinds of voltage controlled by the primary transfer roller are applied to the photosensitive drum charged during non-image formation, and the current value flowing at that time is applied to the primary transfer roller or the intermediate transfer roller. Measure the resistance value of the transfer belt and set an appropriate transfer voltage value. Then, when the toner image is transferred to the intermediate transfer belt, a transfer voltage set to an appropriate value is subjected to constant voltage control and applied to the primary transfer roller.

However, when this ATVC control is performed, in the configuration of Patent Document 1, the current flowing to the photosensitive drum side is not stable, and it may not be possible to perform highly accurate ATVC control. This is intended to prevent local abrasion of the photosensitive layer in the vicinity of the charging roller in Patent Document 1, and a region where a current flows in the rotation axis direction of the photosensitive drum when a voltage is applied to the primary transfer roller ( (Transfer area) is not considered. Therefore, a potential difference may occur in the transfer area after charging for the reason described below.

The reason why a potential difference occurs in the transfer area after charging is as follows. That is, the discharge is suppressed in the region where the static elimination light is not irradiated by the shield members near both ends of the charging roller. On the other hand, discharge is performed in other regions. Therefore, in the area where the static elimination light is shielded, the surface of the photoconductor drum is less scraped than in the area where the static elimination light is irradiated. When the image formation is continued with the difference in the scraped amount, the difference in the film thickness of the photosensitive layer becomes large, and when the photosensitive drum is charged in the state where the film thickness difference is large, the film thickness difference becomes large. A corresponding potential difference occurs. In particular, at the end of the life of the photosensitive drum, the difference in film thickness of the photosensitive layer becomes extremely large, which is even more noticeable in a photosensitive drum having a long life. For this reason, when there is a region irradiated with the static elimination light and a region shielded in the transfer region, a film thickness difference occurs between them and a potential difference occurs in the surface potential after charging.

Therefore, an object of the present invention is to provide an image forming apparatus capable of preventing the photosensitive layer of the photosensitive drum from being locally scraped near the end portion of the charging roller, and capable of executing highly accurate ATVC control.

In order to achieve this object, an image forming apparatus according to the present invention includes a rotatable image carrier that carries a toner image, a charging roller that charges the surface of the image carrier, and the image carrier. The transfer member that transfers the toner image onto the transfer medium, and the image carrier and the charging roller are provided downstream of the contact position between the image carrier and the transfer member in the rotation direction of the image carrier. A light source that emits discharge light for discharging the surface of the image bearing member upstream of the contact position toward the surface of the image bearing member from a direction orthogonal to the rotation axis direction of the image bearing member , the rotation axis direction A plurality of light sources arranged side by side, and a light amount reducing member that reduces the light amount of the static elimination light emitted from the light source and applied to the image carrier, the image being in a direction orthogonal to the rotation axis direction. An image forming apparatus having a light amount reducing member arranged at a position facing a carrier , wherein an area of the image carrier that contacts the charging roller is a charging area, and the image carrier that contacts the transfer member. Assuming that the body region is a transfer region, the charging region is wider than the transfer region in the rotation axis direction of the image carrier, and the light amount reducing member has the transfer region inside the charging region in the rotation axis direction. It is arranged so as to reduce the light amount of the static elimination light applied to the outer region, and is arranged so as not to reduce the light amount of the static elimination light applied to the transfer region, and the rotation of the plurality of light sources is performed. It said light source arranged at the furthest outside in the axial direction, the a inner is from the end of the charged region, than the end of the transfer region is disposed outside and said Rukoto.

With this configuration, since the charge is uniformly removed in the transfer area of the photosensitive drum, no potential difference occurs in the transfer area immediately before charging. Therefore, there is no difference in the amount of discharge in the transfer area during charging, and there is no difference in the amount of abrasion on the surface of the photosensitive drum. Therefore, even if the photosensitive layer is scraped after being used for a long period of time, the amount of scraping is uniform, so that no potential difference occurs in the transfer area of the photosensitive drum after charging. Therefore, when performing the ATVC control, a potential difference does not occur in the region where the current on the photoconductor drum 5 side flows, so that the ATVC control with high accuracy can be performed.

Further, since the static elimination light is shielded in the vicinity of both ends of the charging roller, the potential difference between the both ends of the charging roller and the photosensitive drums in the vicinity thereof during charging becomes small, and discharge can be suppressed. Therefore, it is possible to prevent the photosensitive layer of the photosensitive drum from being locally scraped near the end portion of the charging roller, and it is possible to prevent the occurrence of a leak image.

FIG. 1 is a schematic sectional view of an image forming apparatus according to the present invention. It is a figure for explaining the control method of the transfer voltage concerning the present invention. It is a figure explaining the structure of the pre-exposure apparatus which concerns on this invention. It is a figure explaining the structure of the shielding member which concerns on this invention. It is a figure explaining the area|region which shields the static elimination light of the shielding member which concerns on this invention. It is a figure explaining the area|region which shields the static elimination light of the shielding member which concerns on this invention. 6 is a graph showing an experimental result of the abrasion amount of the photosensitive layer when the image forming apparatus according to the present invention performs intermittent printing.

(First embodiment)
<Image forming device>
Hereinafter, first, the overall configuration of the image forming apparatus A according to the present invention will be described with reference to the drawings together with the operation during image formation.

The image forming apparatus A according to the present embodiment is a full-color laser printer that employs an in-line method and intermediate transfer method in which photoconductor drums are arranged in a line. As shown in FIG. 1, the image forming apparatus A includes an image forming unit that transfers a toner image onto a sheet, a sheet feeding unit that supplies the sheet to the image forming unit, and a fixing unit that fixes the toner image on the sheet. I have it.

The image forming unit includes a process cartridge 4, which is attachable to and detachable from the main body of the image forming apparatus A, an intermediate transfer unit 10, a pre-exposure device 2 (static elimination unit), and a laser scanner unit 9.

In the process cartridge 4, process cartridges 4y, 4m, 4c, and 4k corresponding to each color of yellow, magenta, cyan, and black are arranged in a line. Further, each process cartridge 4 has an organic photoconductive layer (photosensitive layer), and is provided with a rotatably provided photosensitive drum 5 (5y, 5m, 5c, 5k) as an image bearing member. Further, a charging roller 6 (6y, 6m, 6c, 6k) is provided which is provided so as to face the photoconductor drum 5 and contacts the photoconductor drum 5 to charge the same. Further, the developing device 7 (7y, 7m, 7c, 7k), the cleaning blade 8 (8y, 8m, 8c, 8k), and a shielding member 100 (100y, 100m, 100c, 100k) as a shielding means are provided.

The pre-exposure device 2 (2y, 2m, 2c, 2k) is substantially orthogonal to the rotation direction of the photoconductor drum 5 in order to eliminate the residual charge on the surface of the photoconductor drum 5 in preparation for the next image formation after the transfer process. From the direction, the surface of the photosensitive drum 5 is irradiated with the static elimination light L.

The shielding member 100 regulates the irradiation area of the static elimination light L irradiated by the pre-exposure device 2.

The intermediate transfer unit 10 includes a primary transfer roller 17 (17y, 17m, 17c, 17k) as a transfer member, an intermediate transfer belt 11, a driving roller 12, a tension roller 13, a secondary transfer counter roller 14a, and a cleaning device 18. Prepare

The intermediate transfer belt 11 is an endless cylindrical belt, is in contact with the photosensitive drum 5, and the driving roller 12 receives a rotational force from a driving source such as a motor (not shown), whereby the intermediate transfer belt 11 moves in the direction of arrow X shown in FIG. Rotate. The intermediate transfer belt 11 is stretched around a drive roller 12, a tension roller 13, and a secondary transfer counter roller 14a.

The primary transfer rollers 17 are arranged side by side in contact with the respective photosensitive drums 5 via the intermediate transfer belt 11, and press the intermediate transfer belt 11 in the direction of the photosensitive drum 5 so that the intermediate transfer belt 11 and the photosensitive drum 5 are connected to each other. To form a primary transfer portion N1.

At the time of image formation, when a control unit (not shown) issues a print signal, the sheets stacked and stored in the sheet stacking unit 1 are sent out by the feeding roller 3 to the image forming unit.

On the other hand, the surface of the photosensitive drum 5 is charged by the charging roller 6. Then, the laser scanner unit 9 emits a laser beam from a light source (not shown) provided inside, and irradiates the photosensitive drum 5 with the laser beam. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 5. By developing this electrostatic latent image by the developing device 7, a toner image is formed on the photosensitive drum 5. The toner image formed on the photosensitive drum 5 of each process cartridge 4 is applied with a transfer bias having a polarity opposite to that of the toner on the primary transfer roller 17, so that the intermediate transfer belt, which is a transfer medium, is transferred at the primary transfer portion N1. 11 is primarily transferred. After that, the intermediate transfer belt 11 rotates in the direction of the arrow X shown in FIG. 1, and the toner image that has been primarily transferred moves downstream in the rotational direction by the rotation of the intermediate transfer belt 11. After that, the toner image reaches the secondary transfer portion N2 formed by the secondary transfer counter roller 14a and the secondary transfer roller 14b, and the toner image is transferred to the sheet there.

The sheet on which the toner image has been transferred is sent to the fixing device 15, heated and pressed to fix the toner image on the sheet, and then conveyed by the discharge roller 16 and discharged to the discharge portion.

After the image formation (after the transfer of the toner image carried on the photoconductor drum 5), the surface of the photoconductor drum 5 is irradiated with the neutralization light L from the pre-exposure device 2 to neutralize the residual charges on the surface of the photoconductor drum 5. This prepares for the next image formation.

<About ATVC control>
Next, the ATVC control executed at the time of primary transfer in this embodiment will be described.

In the ATVC control, first, a voltage controlled by a transfer power supply (voltage applying means) is applied to the primary transfer roller 17 during non-image formation while changing the output voltage value. Next, the resistance value of the primary transfer roller 17 or the intermediate transfer belt 11 is measured from the current value flowing at that time, and when the toner image is transferred onto the sheet, an appropriate transfer voltage corresponding to the resistance value is controlled by constant voltage control. This is a control method of applying to the primary transfer roller 17.

Specifically, first, the photosensitive drum 5 is charged by the charging roller 6, and then, as shown in FIG. 2, a predetermined number of types of voltages (V1, V2, V3) are applied to the primary transfer roller 17. An electric current is applied to the photosensitive drum 5 side. At this time, the current value (I1, I2, I3) corresponding to this voltage value (V1, V2, V3) is detected by a current value sensor (current value detection means) not shown. Then, the target transfer voltage Vtarget (appropriate value) corresponding to the target transfer current Ittarget is calculated from these detection results, and this is set as the transfer voltage of the primary transfer roller 17.

The timing of setting the transfer voltage by the ATVC control is set immediately before image formation in order to cope with endurance variations in resistance values of the primary transfer roller 17 and the intermediate transfer belt 11 and environmental variations. Further, the transfer voltage may be set independently for each color, or may be set at the primary transfer portion of a certain color.

Although the transfer voltage value applied to the primary transfer roller 17 has been described here, the ATVC control can also set the transfer voltage value applied to the secondary transfer roller 14b. In addition to the intermediate transfer type image forming apparatus, the transfer voltage value of the image forming apparatus configured to directly transfer the toner image to the sheet at the transfer nip portion formed by the photosensitive drum and the transfer roller may be set. Is also possible.

<Pre-exposure device and shielding member>
Next, the configurations of the pre-exposure device 2 and the shielding member 100 of this embodiment will be described in detail.

As shown in FIG. 3, the pre-exposure device 2 has a configuration in which the light sources 20 are arranged on the substrate 19 at equal intervals. In this embodiment, as the light source 20, a chip-type LED that has a low driving voltage and is easy to miniaturize is used. The distance between the light sources is 28.5 mm. However, the present invention is not limited to this, and the light source 20 may be a system using a light guide, a system using a halogen lamp, or the like.

As shown in FIG. 4, the shielding member 100 is provided on the optical path of the static elimination light L in order to regulate the irradiation area of the static elimination light L emitted by the pre-exposure device 2. By providing the shielding member 100 in the process cartridge 4, the distance between the photosensitive drum 5 and the shielding member 100 becomes short, and the shielding accuracy is further improved.

Further, the shielding member 100 shields the static elimination light L irradiated to the outside of the transfer area, which is inside the charging area including both ends of the charging area in the rotation axis direction of the photosensitive drum 5, so as to reduce the light amount. Set up in. The reason will be described in detail below.

First, as shown in FIG. 5, the exposure area where the laser scanner unit 9 exposes the photosensitive drum 5 is set to Wa. Further, in the rotational axis direction R of the photoconductor drum 5, a transfer area in which a current flows when a voltage is applied to the primary transfer roller 17 is Wb. Further, in the rotational axis direction R of the photosensitive drum 5, the charging area charged by the charging roller 6 is Wc. Further, the irradiation region of the surface of the photoconductor drum 5 to which the static elimination light L is irradiated is Ws. In addition, one of the plurality of light sources 20 whose position in the rotation axis direction R overlaps with the transfer region Wb is defined as a first light source 20a, and one which does not overlap with the transfer region Wb (that overlaps with a region outside the transfer region Wb). It is called the second light source 20b.

At this time, the relationship of Wa<Wb is established. That is, the transfer area is wider than the exposure area of the photoconductor drum 5 by the laser scanner unit 9. This is because the exposed area is the image forming area, and therefore the transfer area to which the toner image is transferred must be at least the image forming area.

Further, the relationship of Wb<Wc is established. This is inside the charging area in the rotation axis direction R of the photoconductor drum 5, and in order for the shielding member 100 to shield the static elimination light L irradiated to the outside of the transfer area, the charging area is larger than the transfer area. This is because it needs to be wide.

Here, the shielding member 100 is provided so that Wb<Ws<Wc is satisfied in the irradiation region Ws to which the charge removal light L is irradiated. In the rotation axis direction R, the irradiation area Ws corresponds to the distance between the inner ends of the shielding member 100. That is, in the rotational axis direction R of the photoconductor drum 5, the shielding member 100 is provided so as to shield the static elimination light L that is irradiated inside the charging area and outside the transfer area. At this time, the shielding member 100 is provided so as to shield the charge removal light L emitted to both ends of the charging region of the photosensitive drum 5 in the rotation axis direction R in particular. That is, the shielding member 100 is arranged only in a position facing the area inside the charging area Wc including both ends of the charging area Wc and outside the transfer area Wb in the rotational axis direction R. Further, the shielding member 100 is arranged at a position that does not overlap the first light source 20a in the rotation axis direction R. Further, the shielding member 100 is arranged at a position at least partially overlapping the second light source 20b with respect to the rotation axis direction R.

In the present embodiment, with respect to the rotation axis direction R, the width of the charging area Wc of the photosensitive drum 5 is 228 mm, the width of the transfer area Wb is 224.3 mm, and the irradiation area Ws is 226.4 mm.

With such a configuration, the static elimination light L is not shielded in the transfer area of the photosensitive drum 5, so that the static charge is uniformly discharged in the transfer area, and no potential difference occurs in the transfer area immediately before charging. Therefore, there is no difference in the amount of discharge in the transfer area during charging, and there is no difference in the amount of abrasion on the surface of the photosensitive drum 5. For this reason, even if the photosensitive layer is scraped after being used for a long period of time, the photosensitive layer is scraped uniformly in the transfer area, so that no potential difference is generated in the transfer area after charging. Therefore, when the ATVC control is performed, a potential difference does not occur in the transfer area of the photoconductor drum 5, so that the ATVC control with high accuracy can be performed.

Further, since the static elimination light L radiated near both ends of the charging roller 6 is shielded, the potential difference between the both ends of the charging roller 6 and the photosensitive drum 5 around the charging roller 6 becomes small at the time of charging, and the discharge can be suppressed. it can. Therefore, it is possible to prevent the photosensitive layer of the photosensitive drum 5 from being locally scraped near both ends of the charging roller 6, and it is possible to prevent a leak image from occurring.

The shielding member 100 includes not only a member that completely blocks the static elimination light L but also a member that reduces the light amount of the static elimination light L. That is, it is only necessary to reduce the potential difference between both ends of the charging roller 6 and the photosensitive drum 5 around the charging roller 6 at the time of charging, so that the amount of discharge can be suppressed. That is, the shielding member 100 is a light amount reducing member that reduces the amount of light emitted from the light source 20 to the photosensitive drum 5.

Further, since the image forming apparatus A of this embodiment uses the contact type charging roller 6 and the primary transfer roller 17, the charging area means an area where the charging roller 6 and the photosensitive drum 5 are in contact with each other. The transfer area means an area where the primary transfer roller 17 and the photosensitive drum 5 are in contact with each other via the intermediate transfer belt 11.

<Experimental results>
The results of a comparative experiment on the amount of abrasion of the photosensitive layer of the photosensitive drum 5 during intermittent printing will be shown below. In this experiment, the present embodiment in which the shielding member 100 shields the static elimination light L irradiated inside the charging area including both ends of the charging area in the rotation axis direction R of the photoconductor drum 5 and outside the transfer area. The image forming apparatus A having the above configuration is referred to as an “embodiment”. Further, a configuration without the shielding member 100 is referred to as “Comparative Example 1”. Further, as shown in FIG. 6, a configuration in which the static elimination light L irradiated to the inside of the transfer area in the rotation axis direction R of the photosensitive drum 5 is shielded by the shielding member 100 is referred to as “Comparative Example 2”.

As an experimental condition, the image forming apparatus was left to stand for 1 day in the experimental environment of 15.0° C. and 10% Rh, and after acclimatizing to the experimental environment, the experiment was performed after printing 10,000 sheets. The content of the experiment was as follows: a horizontal line recording image with an image ratio of 2% was intermittently passed every two sheets to print 10,000 sheets, and after the initial film thickness of the experiment and 10,000 sheets were printed, The amount of abrasion of the photosensitive layer was calculated from the difference from the surface film thickness.

As a result, as shown in FIG. 7, in the structure of Comparative Example 1, the photosensitive layer was largely scraped near the end portion of the charging roller 6, resulting in local scraping of the photosensitive layer. This is because the shielding member 100 is not provided, and a strong discharge is generated near the end of the charging roller 6. If image formation is continued for a long time in such a state, a leak image will occur. The direction orthogonal to the rotation direction of the photosensitive drum is a direction parallel to the rotation axis direction R.

In addition, in the configuration of Comparative Example 2, by providing the shielding member 100, local abrasion of the photosensitive layer near the end portion of the charging roller 6 was eliminated. However, since the static elimination light L applied to the transfer area was shielded by the shielding member 100, an area where the amount of abrasion of the photosensitive layer was small was partially generated in the transfer area. If image formation is continued for a long time in such a state, the accuracy of ATVC will be reduced.

On the other hand, in the configuration of the embodiment, local abrasion of the photosensitive layer is eliminated near the end of the charging roller 6. Moreover, the amount of abrasion of the photosensitive layer was almost uniform in the transfer area. Therefore, even if the image formation is continued for a long period of time, it is possible to prevent the occurrence of a leak image and to perform highly accurate ATVC.

In the present embodiment, if the uniformity of the scraped amount of the photosensitive layer of the photoconductor drum 5 within the transfer area is at a constant level at which ATVC with good accuracy can be performed, the shielding member 100 can be used to transfer the inside of the transfer area. The configuration may be such that a part of the static elimination light L that is applied to the interior is shielded. In this embodiment, the shielding member 100 may shield at least a part of the static elimination light L emitted from the second light source 20b to the transfer region Wb. Even with such a configuration, the transfer area Wb is mainly irradiated with the static elimination light L emitted from the first light source 20a, so that the amount of abrasion of the photosensitive layer of the photosensitive drum 5 is uniform in the transfer area Wb. ATVC with good accuracy can be set to a certain level or above at which it can be executed. Further, with such a configuration, it is possible to further shield the static elimination light L emitted from the first light source 20a and applied to both ends of the charging region.

In the present embodiment, the pre-exposure device 2 is provided in the main body of the image forming apparatus A, but the present invention is not limited to this, and the pre-exposure device 2 may be provided in the process cartridge 4. Since the position of the shielding member 100 is determined by the relative positional relationship with the position of the pre-exposure device 2, providing the both in the process cartridge 4 makes it easier to regulate the irradiation area of the static elimination light L.

Although the shielding member 100 is provided in the process cartridge 4 in this embodiment, the present invention is not limited to this, and the shielding member 100 may be provided in the image forming apparatus A main body. As a result, the manufacturing cost can be reduced as compared with the configuration in which the shielding member 100 is provided in the process cartridge 4, which is a consumable item.

Further, in the present embodiment, an intermediate transfer type image forming apparatus capable of forming a color image is illustrated, but the present invention is not limited to this, and is also suitable for an image forming apparatus capable of forming a monochrome image. can do. In this case, the toner image is directly transferred to the sheet at the transfer nip portion formed by the photosensitive drum and the transfer roller without using the intermediate transfer belt. Therefore, the inside of the transfer area in this case means an area where the transfer roller and the photoconductor drum are in direct contact, or an area where they are in contact with each other via the sheet.

Further, the image forming apparatus may be a printer, a copying machine, a facsimile machine, or a multi-function machine combining these functions. Further, it may be an image forming apparatus which uses a recording material carrier and sequentially superimposes and transfers toner images of respective colors on the recording material carried by the recording material carrier.

DESCRIPTION OF SYMBOLS 1... Sheet stacking unit 2... Pre-exposure device 3... Feed roller 4... Process cartridge 5... Photosensitive drum 6... Charging roller 7... Developing device 8... Cleaning blade 9... Laser scanner unit 10... Intermediate transfer unit 11... Intermediate transfer Belt 12... Driving roller 13... Tension roller 14a... Secondary transfer counter roller 14b... Secondary transfer roller 15... Fixing device 16... Ejection roller 17... Primary transfer roller 18... Cleaning device 19... Substrate 20... Light source 100... Shielding member A Image forming apparatus L... Static elimination light

Claims (7)

A rotatable image carrier that carries a toner image;
A charging roller for charging the surface of the image carrier,
A transfer member for transferring the toner image carried by the image carrier to a transfer medium,
In the rotation direction of the image carrier, the surface of the image carrier is discharged downstream of the contact position between the image carrier and the transfer member and upstream of the contact position between the image carrier and the charging roller. A light source that emits static elimination light toward the surface of the image carrier from a direction orthogonal to the rotation axis direction of the image carrier , and a plurality of light sources arranged side by side in the rotation axis direction ,
A light amount reducing member that reduces the light amount of the static elimination light emitted from the light source and applied to the image carrier, and is disposed at a position facing the image carrier in a direction orthogonal to the rotation axis direction. A light amount reducing member ,
An image forming apparatus having:
When the area of the image carrier that contacts the charging roller is the charging area and the area of the image carrier that contacts the transfer member is the transfer area, the charging area is the transfer area in the rotational axis direction of the image carrier. Wider than the area,
The light amount reducing member is arranged so as to reduce the light amount of the static elimination light that is irradiated to an area inside the charging area and outside the transfer area with respect to the rotation axis direction, and is irradiated to the transfer area. Arranged so as not to reduce the amount of static elimination light ,
Most the light source arranged outside is a inner is from the end of the charging region, characterized Rukoto disposed outside the end portion of the transfer area in the rotation axis direction of the plurality of said light sources Image forming apparatus. A rotatable image carrier that carries a toner image;
A charging roller for charging the surface of the image carrier,
A transfer member for transferring the toner image carried by the image carrier to a transfer medium,
In the rotation direction of the image carrier, the surface of the image carrier is discharged downstream of the contact position between the image carrier and the transfer member and upstream of the contact position between the image carrier and the charging roller. A light source that emits static elimination light toward the surface of the image carrier from a direction orthogonal to the rotation axis direction of the image carrier , and a plurality of light sources arranged side by side in the rotation axis direction ,
A light amount reducing member that reduces the light amount of the static elimination light emitted from the light source and applied to the image carrier, and is disposed at a position facing the image carrier in a direction orthogonal to the rotation axis direction. A light amount reducing member ,
An image forming apparatus having:
When the area of the image carrier that contacts the charging roller is a charging area and the area of the image carrier that contacts the transfer member is a transfer area, the charging area is the transfer area in the rotation axis direction of the image carrier. Wider than the area,
At least a part of the light amount reducing member is arranged between the end of the charging region and the end of the transfer region with respect to the rotation axis direction ,
Most the light source arranged outside is a inner is from the end of the charging region, characterized Rukoto disposed outside the end portion of the transfer area in the rotation axis direction of the plurality of said light sources Image forming apparatus. Voltage applying means for applying a voltage to the transfer member,
A current value detecting means for detecting a current value flowing when the voltage is applied by the voltage applying means,
The voltage is applied to the transfer member while changing the voltage by the voltage application unit, the current value corresponding to the voltage is detected by the current value detection unit, and the voltage is changed based on the detected current value. The image forming apparatus according to claim 1, wherein the image forming apparatus is set. The plurality of light sources includes a first light source that overlaps the transfer area in the rotation axis direction, and a second light source that overlaps the charging area in the rotation axis direction and does not overlap the transfer area,
The light amount decrease member, an image forming apparatus according to any one of claims 1 to 3, characterized in that the said second light source with respect to the rotation axis and at least partially disposed in a position overlapping. The light amount reducing member is arranged at a position that does not overlap with the first light source in the rotation axis direction so as not to reduce the light amount of the static elimination light emitted toward the transfer region. Item 4. The image forming apparatus according to item 4 . The width of the irradiation region, which is a region in which the charge eliminating light is not reduced by the light amount reducing member without being reduced by the charge eliminating light, is wider than the width of the transfer region and wider than the width of the charging region. the image forming apparatus according to any one of claims 1 to 5, characterized in that also small. The light amount decrease member, an image forming apparatus according to any one of claims 1 to 6, characterized in that a member that does not transmit the lamp light emitted from the light source.

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