JP5899780B2 - Charging device, cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a charging device, a cartridge, and an image forming apparatus.

  As the charging device, there is an MHCD (Micro Hollow Cathode Discharge) type. The MHCD charging device includes a first electrode, a first intermediate layer having a higher resistivity than the first electrode, a second intermediate layer for preventing conduction, and a second electrode in order of increasing distance from the photosensitive member, which is an object to be charged. The electrodes are sequentially stacked and have a number of holes that penetrate the second electrode and the second intermediate layer. In this charging device, when a voltage higher than that of the second electrode is applied to the first electrode, a glow discharge is generated due to a potential difference between the first intermediate layer and the second electrode, and charged particles are emitted. Charged particles move to the surface of the photoreceptor due to a drift electric field generated between the bodies, and the photoreceptor is charged. Patent Document 1 listed below discloses such an MHCD charging device.

JP 2011-069879 A

  An object of the present invention is to suppress the generation of ozone due to the discharge of an MHCD charging device.

  A charging device according to a first aspect of the present invention includes a first electrode, a first intermediate layer provided on one surface of the first electrode, and having a volume resistivity higher than that of the first electrode, and the first intermediate A second intermediate layer that is provided on a surface opposite to the surface on which the first electrode is provided and that prevents conduction, and has a plurality of holes that pass through the second intermediate layer. And a second surface of the second intermediate layer in the hole from the first surface of the second intermediate layer opposite to the surface on which the first intermediate layer is provided. And a second electrode provided continuously on a predetermined portion of the surface.

  In the charging device according to claim 2 of the present invention, in the charging device, the diameter of the hole of the second intermediate layer increases from the first intermediate layer side to the second electrode side. The plurality of holes are formed in the substrate.

  According to a third aspect of the present invention, there is provided a cartridge for exposing a photosensitive member as an object to be charged, the charging device according to the first or second aspect for charging the photosensitive member, and the photosensitive member charged by the charging device. And a developing device that develops the electrostatic latent image formed by the developer.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising: a photosensitive member that is an object to be charged; the charging device according to claim 1 that charges the photosensitive member; and the photosensitive member that is charged by the charging device. A developing device that develops the electrostatic latent image formed by exposure with a developer, a transfer unit that transfers the image developed by the developing device to a recording medium, and an image that is transferred to the recording medium by the transfer unit And fixing means for fixing the image to the recording medium.

  According to the first aspect of the present invention, in the charging device of the MHCD system, charging is performed as compared with the case where the second electrode is not continuously provided on the first surface and the second surface of the second intermediate layer. Ozone generation due to the discharge of the apparatus can be suppressed.

  According to the second aspect of the present invention, the charging efficiency of the object to be charged is improved as compared with the case where the diameter of the hole portion is not increased from the first intermediate layer side toward the second electrode side. Can be improved.

  According to the third aspect of the present invention, in the MHCD charging device, charging is performed as compared with the case where the second electrode is not continuously provided on the first surface and the second surface of the second intermediate layer. Ozone generation due to the discharge of the apparatus can be suppressed.

  According to the invention of claim 4, in the charging device of the MHCD system, charging is performed as compared with the case where the second electrode is not continuously provided on the first surface and the second surface of the second intermediate layer. Ozone generation due to the discharge of the apparatus can be suppressed.

1 is a diagram illustrating a hardware configuration of an image forming apparatus according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration of an image forming engine according to Embodiment 1. FIG. It is the figure which looked at the conventional charging device from the to-be-charged object side. It is sectional drawing in the II line | wire of FIG. FIG. 5 is an enlarged view of a part of the charging device of FIG. 4. It is a figure at the time of changing the thickness of the 2nd intermediate | middle layer of FIG. FIG. 3 is an enlarged view of a part of the charging device according to the first embodiment. It is a figure which shows the measurement result of the ozone generation amount of the charging device which concerns on Embodiment 1, and the conventional charging device. FIG. 6 is an enlarged view of a part of a charging device according to a second embodiment.

<Embodiment 1>
(Constitution)
FIG. 1 is a diagram illustrating a hardware configuration of an image forming apparatus 100 which is an example of an image forming apparatus according to the present invention. The control unit 4 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU controls each unit connected to the control unit 4 by executing a control program stored in the ROM. The storage unit 5 is a storage device such as a hard disk, for example, and stores data such as an OS (Operating System) and application programs.

  The operation accepting unit 1 has, for example, a touch panel and various keys (such as a start key, a reset key, and a numeric key), and displays an image representing an operation element corresponding to a user operation content on the touch panel under the control of the control unit 4. Then, a signal indicating an operation element or key operation in an area touched by the user is sent to the control unit 4. A communication I / F (Interface) 6 is connected to a communication means (not shown) such as a LAN (Local Area Network), and communicates with the image forming apparatus 100 according to a communication protocol such as TCP / IP (Transmission Control Protocol / Internet Protocol). Mediates communication with other devices. The image reading unit 2 optically reads a document and converts it into image signals representing R (Red), G (Green), and B (Blue) colors. The image reading unit 2 includes a platen glass, a light source, a reflecting mirror, and an image sensor (not shown). The image reading unit 2 irradiates the original on the platen glass with light from a light source, converts the reflected light incident on the image sensor through the reflecting mirror into image signals representing R, G, and B colors, and performs image processing. Send to part 3.

  The image processing unit 3 performs A / D conversion on each color image signal, and performs image processing such as color conversion, enlargement / reduction, background removal, binarization, and the like. In color conversion processing, an image composed of R, G, and B colors is decomposed into images of Y (Yellow), M (Magenta), C (Cyan), and K (Black) colors to generate image data. . The image data is read by the control unit 4 at a predetermined timing and supplied to the image forming unit 7. The image forming unit 7 includes image forming engines 10Y, 10M, 10C, and 10K, a transfer belt 20, a medium supply unit 30, and a fixing device 40. The image forming engines 10Y, 10M, 10C, and 10K respectively apply toner images of Y, M, C, and K colors to the surface of the transfer belt 20 by electrophotography based on the image data supplied from the control unit 4. Overlapping to form. Hereinafter, the configuration of the image forming engine will be described. Since the configuration of each image forming engine is common, when they are not distinguished from each other, they are collectively referred to as the image forming engine 10, and Y, M, C, and K are omitted.

  FIG. 2 is a diagram illustrating a configuration of the image forming engine 10. The image forming engine 10 includes a photoreceptor 11, a charging device 200, an exposure device 13, a developing device 14, a transfer device 15, and a cleaning device 16. The photoconductor 11 is composed of a cylindrical member having a photoconductive film formed on its surface, holds an electrostatic latent image formed by exposure of the surface, and rotates in the direction of arrow A by driving a motor (not shown). . The charging device 200 is an example of a charging device according to the present invention. The charging device 200 has a charging roll that rotates following the rotation of the photoconductor 11, and charges the surface of the photoconductor 11 to a certain potential by applying a voltage to the charging roll by a voltage application unit (not shown). Details of the charging device 200 will be described later.

  The exposure device 13 exposes the surface of the photoconductor 11 according to the image data supplied from the control unit 4 to form an electrostatic latent image on the surface of the photoconductor 11. The developing device 14 stores the developer, and toner adheres to the surface of the photoconductor 11 due to a potential difference between the developer charged to a predetermined potential and the latent image on the photoconductor 11, and the toner image is formed on the photoconductor 11. Is formed. The transfer belt 20 is wound around a driving roller 21 and a roller 22 shown in FIG. When the driving roller 21 is driven to rotate, the transfer belt 20 is driven in the direction of arrow B. A transfer device 15 is provided at a position facing the photoconductor 11 via the transfer belt 20. The transfer device 15 applies a primary transfer voltage having a polarity opposite to the polarity to which the toner is charged by a voltage application unit (not shown) to the photosensitive member 11, and is charged by the potential difference generated between the photosensitive member 11 and the transfer belt 20. Is transferred to the transfer belt 20, and the toner image is primarily transferred to the transfer belt 20. The cleaning device 16 removes toner remaining on the surface of the photoconductor 11 without being primarily transferred.

  Returning to FIG. The medium supply unit 30 accommodates a recording medium P such as paper. The medium supply unit 30 sends the recording medium P one by one to the transport path 32 in synchronization with the primary transfer timing. When the recording medium P reaches the contact area between the transfer roller 23 and the transfer belt 20, a secondary transfer voltage is applied to the transfer roller 23 by a voltage application unit (not shown), and the transfer roller 23 causes the recording medium P to be opposite to the transfer belt 20. Charged to polarity. The toner image on the transfer belt 20 is secondarily transferred to the surface of the recording medium P by electrostatic attraction and pressing of the transfer roller 23, and is sent to the fixing device 40. The fixing device 40 fixes the toner image on the surface of the recording medium P by heating and pressing the recording medium P onto which the toner image has been secondarily transferred. The transfer device 15 and the transfer roller 23 are examples of the transfer unit according to the present invention, and the fixing device 40 is an example of the fixing unit according to the present invention.

  Next, the charging device 200 will be described. Here, first, a conventional MHCD charging device is shown in FIGS. FIG. 3 is a view of the charging device 900 viewed from the side of the photosensitive member 11 that is an object to be charged. FIG. 4 is a cross-sectional view taken along the line II of FIG. 3 and shows the positional relationship with the photoconductor 11. FIG. 5 is an enlarged schematic view of a part of the charging device 900 shown in FIG. The charging device 900 is configured by laminating a first electrode 901, a first intermediate layer 902 having a higher resistivity than the first electrode 901, a second intermediate layer 903 that blocks conduction, and a second electrode 904. A plurality of holes 905 penetrating the second electrode 904 and the second intermediate layer 903 are provided.

  When a voltage is applied to the first electrode 901 and the second electrode 904 by the power source 906 via the feeder lines 907 and 908, a discharge is generated due to a potential difference between the first intermediate layer 902 and the second electrode 904, and charged particles are released. At the same time, ozone corresponding to the amount of electric power discharged is generated. The ozone generated by the discharge contaminates the photoreceptor 80 and causes image defects such as white spots. As the distance between the first electrode 901 and the second electrode 904 increases, the applied voltage at which discharge starts according to Paschen's law increases, and the amount of ozone generated also increases. Therefore, as a method of suppressing the amount of ozone generated as compared with the case of FIG. 5, for example, as shown in FIG. 6, a method of reducing the thickness of the second intermediate layer 903 of the charging device 900 to half that of FIG. In this case, the voltage at which discharge is started is lower than in the case of FIG. 5 and the amount of ozone generation is also reduced, but the second intermediate layer 903 in an unintended region other than the hole 905 is reduced by reducing the distance between the electrodes. However, a local short circuit causes excessive abnormal discharge, resulting in a problem of uneven charging due to local excessive discharge.

  In the present embodiment, the charging device 200 is configured as shown in FIG. 7 in order to reduce the amount of ozone generated compared to the conventional case and prevent uneven charging. The charging device 200 is configured by laminating a first electrode 201, a first intermediate layer 202 having a higher resistivity than the first electrode 201, a second intermediate layer 203 for preventing conduction, and a second electrode 204, As in the conventional charging device 900 shown in FIG. 3, the number of holes 205 required for charging are formed at predetermined intervals in the axial direction and the rotational direction of the photoconductor 11. The first electrode 201 and the second electrode 204 are provided with a power source 206 for applying a voltage and power supply lines 207 and 208. The second electrode 204 is formed outside the hole 205, that is, the surface 2031 of the second intermediate layer 203 on the opposite side of the first intermediate layer 202 (hereinafter referred to as the first surface) and the internal space of the hole 205. The second intermediate layer 203 is continuously provided on a side surface (hereinafter referred to as a second surface) 2032 of the second intermediate layer 203 in contact with the second intermediate layer 203. That is, the second electrode 904 of the conventional charging device 900 is formed only on the first surface 2031 of the second intermediate layer 203, whereas the second electrode 204 of the charging device 200 is formed on the first surface. 2031 and the inside of the hole 205 are formed.

In this example, the 1st electrode 201 is comprised with metals, such as iron which performed surface treatments, such as stainless steel, aluminum, copper alloy, these alloys, chromium, nickel, for example. The first intermediate layer 202 is made of, for example, a resin material or rubber having a volume resistivity higher than that of the first electrode 201 such as silicon rubber in which graphite having a volume resistivity of 10 ⁵ Ω · cm to 10 ¹⁰ Ω · cm is dispersed. It is made of a material in which conductive particles are dispersed in the material. The second intermediate layer 203 is made of a material that blocks electrical conduction between the first intermediate layer 202 and the second electrode 204, and is made of an insulator such as a polyimide material or a glass epoxy material. The second electrode 204 is made of a metal such as platinum or gold, for example. The thickness of each layer is, for example, about 100 μm for the first electrode 201, 150 μm for the first intermediate layer 202, 100 μm for the second intermediate layer 203, and about 0.1 μm for the second electrode 204. The diameter of the hole 205, that is, the interval between adjacent second intermediate layers 203 (not including the thickness of the second electrode 204 in the hole 205) is, for example, about 100 μm.

  For example, the second electrode 204 is formed by the following method. Holes having a diameter of 100 μm are formed at predetermined intervals in the axial direction and the rotational direction of the photoconductor 11 in an insulator having a thickness of 100 μm to be the second intermediate layer 203, and the first surface of the insulator is sputtered by sputtering. A gold thin film (thickness of about 0.1 μm or more and 0.5 μm or less) to be the two electrodes 204 is formed. By sputtering, gold wraps around the hole portion of the insulator (that is, the second surface 2032), and a thin film to be the second electrode 204 is formed. The length that goes around the hole is adjusted by the sputtering time, the degree of vacuum in the chamber during sputtering, and the voltage applied between the electrodes that generate sputtering. In the present embodiment, the length of the hole portion, that is, the length of the second electrode 204 formed on the second surface 2032 of the second intermediate layer 203 is, for example, about 50 μm from the first surface 2031. In addition to this method, a thick film forming technique using a lift-off process or a screen printing technique may be used.

  The distance between the second electrode 204 and the surface of the photoreceptor 11 is set to about 200 μm or more and 2000 μm or less. A voltage is applied to the first electrode 201 and the second electrode 204 by the power source 206 so that the potential of the second electrode 204 becomes the target charging potential of the photoconductor 11. For example, the power source 206 applies to the first electrode 201 a voltage increased by about 1.5 kV from 1.0 kV at which discharge occurs between the electrodes with reference to the voltage of the second electrode 204. The photoconductor 11 is grounded. In this case, glow discharge is generated due to the potential difference between the first intermediate layer 202 and the second electrode 204, and charged particles are emitted, and a drift electric field generated between the second electrode 204 and the surface of the photoconductor 11 causes the photoconductor 11 to move. The charged particles move to the surface and the surface of the photoconductor 11 is charged.

  Here, the result of measuring the amount of ozone generated using the conventional charging device 900 shown in FIG. 5 and the charging device 300 according to the present embodiment shown in FIG. 7 is shown in FIG. Hereinafter, the reference numerals are omitted when the configurations of the charging device 900 and the charging device 200 are not distinguished from each other. In this measurement, the thickness and material of each layer of the first electrode 901, the first intermediate layer 902, the second intermediate layer 903, and the second electrode 904 in the charging device 900 and the diameter of the hole 905 are the same as those in the charging device 200. A current measuring electrode having a ground potential connected to the GND potential at a position 500 μm away from the second electrodes 204 and 904 was arranged, and the amount of current flowing into the current measuring electrode and the amount of ozone generated were measured. In this measurement, the applied voltage to the second electrode was set to −750 V, the discharge amount was adjusted by the applied voltage to the first electrode, and the inflow current to the current measuring electrode was adjusted by the discharge amount. Under this condition, the voltage applied to the first electrode at which discharge is started in the gap between the first intermediate layer and the second electrode, that is, the hole space, is −1.7 kV in the case of the conventional charging device 900. In the case of the charging device 200 according to the present embodiment, it was about −1.4 kV. This result follows the result when the distance between the electrodes is 100 μm and 50 μm in the equation derived from Paschen's law, and the distance between the first intermediate layer 902 and the second electrode 904 of the charging device 900 is about 100 μm. This corresponds to the distance between the first intermediate layer 201 and the second electrode 204 of the charging device 200 being about 50 μm.

  In FIG. 8, the measurement result of the charging device 200 according to the present embodiment is indicated by a solid line, and the measurement result of the conventional charging device 900 is indicated by a broken line. As shown in this measurement result, the amount of ozone generated when the current flowing into the current measuring electrode is about the same is 20% to 30% in the charging device 200 according to this embodiment compared to the conventional charging device 900. The degree has been reduced. This is because the distance between the first electrode and the second electrode is shorter in the charging device 200 than in the charging device 900, and the amount of ozone generated is reduced because the voltage at which discharge starts is smaller than in the charging device 900. It is estimated that

  Further, according to an experiment by the inventor, the length of the second electrode 204 formed on the second surface 2032 of the second intermediate layer 203 is made larger than 50 μm, and the first intermediate layer 202 and the second intermediate layer 202 in the hole 205 are formed. When the distance between the electrodes 204 is set to a half, for example, about 25 μm, a phenomenon frequently occurs in which the potential difference between the first electrode 201 and the second electrode 204 becomes a conductive state with a potential difference lower than a voltage at which discharge is started. This is presumed to be due to a creeping current traveling along the side surface of the second electrode 203 that prevents conduction. On the other hand, the length of the second electrode 204 formed on the second surface 2032 of the second intermediate layer 203 is made smaller than 50 μm, and the distance between the first intermediate layer 202 and the second electrode 204 is set to about 90 μm, for example. When set, compared to the case where the distance between the first intermediate layer 202 and the second electrode 204 is about 50 μm, the voltage at which discharge is started increases and the amount of ozone generated also increases. Therefore, when the thickness of the second intermediate layer 203 is about 100 μm, in order to reduce the generation amount of ozone by about 20% to 30% as compared with the conventional case, the first intermediate layer 202 to the second electrode in the hole 205 is reduced. The distance to 204 is preferably set to about 50 μm.

<Embodiment 2>
In Embodiment 1 described above, the example in which the diameter of the hole 205 excluding the portion to which the second electrode 204 is attached is about 100 μm from the first intermediate layer 202 side to the second electrode 204, The charging device 200 </ b> A according to this embodiment is configured such that the diameter of the hole 205 increases from the first intermediate layer 202 side toward the second electrode 204 side. FIG. 9 is an enlarged view of the charging device 200A according to the present embodiment, as in FIG. In addition, about the structure which is common in Embodiment 1, the code | symbol used in Embodiment 1 is attached | subjected.

  As shown in FIG. 9, the hole 205 </ b> A of the charging device 200 </ b> A is formed so as to spread from the first intermediate layer 202 side toward the second electrode 204 side. In this example, the diameter of the hole 205A is, for example, the diameter x1 on the first intermediate layer 202 side is about 80 μm, and the diameter x2 on the second electrode 204 side is about 100 μm. The thicknesses of the first electrode 201, the first intermediate layer 202, the second intermediate layer 203, and the second electrode 204 are the same as those in the first embodiment.

  The second electrode 204 and the second intermediate layer 203 are formed by the following method, for example. In an insulator having a thickness of about 100 μm to be the second intermediate layer 203, the diameter x1 on the side where the first intermediate layer 202 is formed is about 80 μm at predetermined intervals in the axial direction and the rotational direction of the photoconductor 11 respectively. A hole is formed by a laser so that the diameter x2 on the side on which the second electrode 204 is formed is about 100 μm, and a gold thin film (thickness) that becomes the second electrode 204 by sputtering on the surface on the side where the diameter becomes 100 μm. From about 0.1 μm to about 0.5 μm). By sputtering, gold wraps around the hole portion (second surface 2032 of the second intermediate layer 203) in the insulator, and a thin film that becomes the second electrode 204 is also formed in the hole portion. The length that goes around the hole is adjusted by the sputtering time, the degree of vacuum in the chamber during sputtering, and the voltage applied between the electrodes that generate sputtering. In addition to this method, a thick film forming technique using a lift-off process or a screen printing technique may be used.

  In this way, by making the diameter of the hole 205A on the second electrode 204 side larger than the diameter on the first intermediate layer 202 side, compared to the configuration of the first embodiment, the hole 205A has the first intermediate layer 202 in the hole 205A. Charged particles heading toward the photoconductor 11 from the side are less likely to be blocked by the second electrode 204 due to a discharge phenomenon, and the charged particles move efficiently toward the photoconductor 11. Therefore, even if the applied voltage is made smaller than in the case of the first embodiment, a discharge amount similar to that in the first embodiment is obtained, and as a result, the amount of ozone generated is reduced as compared with the first embodiment.

<Modification>
Although the embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments, and can be implemented in various other forms. For example, the above-described embodiment may be modified as follows to implement the present invention, or may be implemented in combination with each modification. Hereinafter, modifications of the present invention will be described.

(1) In Embodiment 1 described above, an example in which the thickness of the second intermediate layer 203 is 100 μm, the thickness of the second electrode 204 is about 0.1 μm, and the diameter of the hole 205 is about 100 μm. As described above, the thickness of the second intermediate layer 203 may be in the range of 100 μm to 200 μm, and the diameter of the hole 205 may be in the range of 50 μm to 200 μm.

(2) In the first and second embodiments described above, the thickness of the second electrode 204 in the hole 205, that is, the thickness of the second electrode 204 on the second surface 2032 of the second intermediate layer 203 is about 0.1 μm. Explained an example. For example, when the thickness of the second electrode 204 is not negligible with respect to the diameter of the hole 205, such as when the thickness of the second electrode 204 in the hole 205 is 20 μm with respect to the diameter of the hole 205 of 100 μm. Compared with the first and second embodiments, charged particles generated in the hole 205 are more easily absorbed by the second electrode 204 in the hole 205, and the charging efficiency of the photoconductor 11 is reduced. Therefore, the thickness of the second electrode 204 in the hole 205 is desirably in the range of 0.1 μm to 1.0 μm.

(3) In the first and second embodiments described above, the thickness of the second electrode 204 in the hole 205 and the thickness of the second electrode 204 outside the hole 205 (the first surface 2031 on the first surface 2031 of the second intermediate layer 203). The example in which the thickness of the two electrodes 204) is about 0.1 μm has been described, but if the conductive state of the second electrode 204 in the hole 205 and the second electrode 204 outside the hole 205 is maintained, The thickness may be different. For example, the thickness of the second electrode 205 outside the hole 205 may be larger than the thickness of the second electrode 205 in the hole 205.

(4) The image forming engine 10 according to the first embodiment described above may include a so-called rotary developing device in which a plurality of developing devices are provided along the circumferential direction of the rotating body, and forms a monochrome image. It may be.

(5) In the first embodiment described above, at least the photoreceptor 11, the charging device 200, and the developing device 14 may be housed in a cartridge that is detachable from the image forming apparatus 100.

DESCRIPTION OF SYMBOLS 1 ... Instruction reception part, 2 ... Image reading part, 3 ... Image processing part, 4 ... Control part, 5 ... Memory | storage part, 6 ... Communication I / F, 7 ... Image forming unit, 10Y, 10M, 10C, 10K, 10 ... image forming engine, 11 ... photosensitive member, 13 ... exposure device, 14 ... developing device, 15 ... transfer device, 16 ... Cleaning device, 20 ... Transfer belt, 30 ... Medium supply unit, 32 ... Conveyance path, 23 ... Transfer roller, 100 ... Image forming apparatus, 200 ... Charging device, 201 ... First electrode 202 ... first intermediate layer 203 ... second intermediate layer 204 ... second electrode 205, 205A ... hole, 206 ... power source, 207, 208 ...・ Power supply line

Claims (4)

A first electrode;
A first intermediate layer provided on one surface of the first electrode and having a higher volume resistivity than the first electrode;
A second intermediate layer that is provided on a surface opposite to the surface on which the first electrode of the first intermediate layer is provided and prevents conduction; a plurality of holes that penetrate the second intermediate layer; A second intermediate layer,
A second surface of the second intermediate layer in the hole from the first surface of the second intermediate layer opposite to the surface on which the first intermediate layer is provided. A charging device comprising: a second electrode provided continuously in a predetermined portion.   The plurality of hole portions are formed in the second intermediate layer so that the diameter of the hole portions increases from the first intermediate layer side toward the second electrode side. Item 2. The charging device according to Item 1. A photoreceptor to be charged; and
The charging device according to claim 1 or 2, wherein the photosensitive member is charged.
And a developing device for developing an electrostatic latent image formed by exposure on the photosensitive member charged by the charging device with a developer. A photoreceptor to be charged; and
The charging device according to claim 1 or 2, wherein the photosensitive member is charged.
A developing device for developing an electrostatic latent image formed by exposure on the photosensitive member charged by the charging device with a developer;
Transfer means for transferring an image developed by the developing device to a recording medium;
An image forming apparatus comprising: a fixing unit that fixes the image transferred onto the recording medium by the transfer unit.

Images