JP5045700B2 - Exposure head, cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an exposure head, a cartridge, and an image forming apparatus.

As the exposure head, exposure heads disclosed in Patent Document 1 and Patent Document 2 are known.
In the exposure head disclosed in Patent Document 1, the exposure of a flat back panel light source is controlled by on / off control of a liquid crystal shutter.

  In the exposure head disclosed in Patent Document 2, a concave portion 40 is formed on the light emitting surface Sb of the substrate S, and an optical adhesive is provided on the bottom portion 40 a of the concave portion 40 at a position facing the pixel electrode 30 of each organic EL element 24. 43 was used to provide the lens array 27. The number of lens arrays 27 corresponding to each organic EL element 24 is provided at a position facing the pixel electrode 30 of each organic EL element 24. Further, each lens array 27 is constituted by a light guide fiber 42 extending toward the photosensitive drum, and a micro lens 26 provided at the end of the light guide fiber 42 on the photosensitive drum side. The length L of each light guide fiber 42 was adjusted as appropriate so that the light emitted from each microlens 26 formed a focal point on the photosensitive drum.

Japanese Patent Laid-Open No. 02-38071 Japanese Patent Laying-Open No. 2007-90813 (FIG. 4)

  It is an object of the present invention to suppress variations in light emission characteristics as compared with a case where no opening member is provided.

The invention of claim 1 is a substrate, an organic EL light emitting part that is provided on the substrate and emits light by organic EL, a scanable opening member having an opening through which light emitted from the organic EL light emitting part passes, An image forming unit that forms an image of light emission that has passed through the opening of the aperture member at a predetermined position, and the light emission is imaged by the image forming unit by changing a scanning speed of the aperture member. This is an exposure head that controls the light emission intensity for each part in the scanning direction of the imaging target .

  According to a second aspect of the present invention, the organic EL light emitting unit has a plurality of organic EL elements arranged at predetermined intervals, and the opening member passes light emitted from the plurality of organic EL elements, respectively. The exposure head according to claim 1, wherein the exposure head has an opening.

  A third aspect of the present invention is the exposure head according to the first or second aspect, further comprising a condensing member that is disposed in the opening and condenses light emitted from the organic EL light emitting unit.

  A fourth aspect of the present invention is the exposure head according to the first or second aspect, wherein the image forming portion is disposed in the opening.

  A fifth aspect of the invention is the exposure head according to any one of the first to fourth aspects, wherein the organic EL light emitting unit is driven in synchronization with scanning of the opening member.

  According to a sixth aspect of the invention, there is provided at least one of a latent image holding body that holds a latent image, a charging device that charges the latent image holding body, and a developing device that develops the latent image of the latent image holding body, and the latent image holding body. An exposure head according to claim 4, which irradiates a body with light to form a latent image.

  The invention of claim 7 is formed by a latent image holding body that holds a latent image, an exposure head according to claim 4 that forms light by irradiating the latent image holding body with light, and the exposure head. And a developing device that develops the latent image.

  According to the structure of Claim 1 of this invention, compared with the case where it does not have an opening member, the variation in a light emission characteristic can be suppressed.

  According to the configuration of the second aspect of the present invention, it is possible to suppress variations in the light emission characteristics as compared with the case where the configuration is not provided.

  According to the structure of Claim 3 of this invention, compared with the case where it does not have a condensing member, condensing efficiency improves.

  According to the configuration of the fourth aspect of the present invention, it is possible to reduce the influence of the position variation of the image forming unit compared to the case where the image forming unit is not disposed in the opening.

  According to the configuration of the fifth aspect of the present invention, it is possible to suppress variations in the light emission characteristics as compared with the case where the organic EL light emitting unit is not motivated to scan the aperture member.

  According to the configuration of the sixth aspect of the present invention, it is possible to suppress the variation in the light emission characteristics as compared with the case of the cartridge not having this configuration.

  According to the configuration of the seventh aspect of the present invention, an image with less density unevenness can be obtained as compared with an image forming apparatus that does not have this configuration.

FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present embodiment. FIG. 2 is a schematic perspective view showing the arrangement of the exposure head according to the present embodiment. FIG. 3 is a schematic diagram schematically showing a state in which light emitted from the exposure head according to the present embodiment is imaged on the photosensitive drum. FIG. 4 is a schematic diagram showing the configuration of the organic EL element. FIG. 5 is a schematic side view showing the arrangement of the exposure head according to the present embodiment. FIG. 6 is a schematic side view showing the configuration of the exposure head according to the first modification. FIG. 7 is a schematic side view showing a configuration of an exposure head according to the second modification. FIG. 8 is a schematic side view showing the configuration of the exposure head according to the third modification. FIG. 9 is a schematic side view showing a configuration of an exposure head according to Comparative Example 1. FIG. 10 is a schematic side view showing a configuration of an exposure head according to Comparative Example 2. FIG. 11 is a table showing evaluation results of the present embodiment / modification examples 1 to 3 and comparative examples 1 and 2.

Below, an example of an embodiment concerning the present invention is described based on a drawing.
(Configuration of the image forming apparatus 10 according to the present embodiment)
First, the configuration of the image forming apparatus 10 according to the present embodiment will be described. FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 10 according to the present embodiment.

  As shown in FIG. 1, the image forming apparatus 10 according to the present embodiment includes an apparatus housing 11 that stores each component, a recording medium storage unit 12 that stores a recording medium P such as paper, and a recording medium P. An image forming unit 14 that forms a toner image on the recording medium, a transport unit 16 that transports the recording medium P from the recording medium storage unit 12 to the image forming unit 14, and a toner image formed by the image forming unit 14 is fixed to the recording medium P. And a recording medium discharge unit (not shown) from which the recording medium P on which the toner image is fixed by the fixing device 18 is discharged.

  The recording medium storage unit 12, the image forming unit 14, the transport unit 16, and the fixing device 18 are stored in the apparatus housing 11.

  The image forming unit 14 includes image forming units 22C, 22M, 22Y, and 22K that form toner images of cyan (C), magenta (M), yellow (Y), and black (K), and an image forming unit 22C, An intermediate transfer belt 24 as an example of an intermediate transfer body to which toner images formed by 22M, 22Y, and 22K are transferred, and toner images formed by image forming units 22C, 22M, 22Y, and 22K are transferred to the intermediate transfer belt 24. A primary transfer roll 26 as an example of a primary transfer member to be transferred; and a secondary transfer roll 28 as an example of a secondary transfer member for transferring a toner image transferred to the intermediate transfer belt 24 to a recording medium P. Yes.

  Each of the image forming units 22C, 22M, 22Y, and 22K includes a photosensitive drum 30 that rotates in one direction (clockwise in FIG. 1) as an example of an image holding body that holds a latent image.

  Around each photosensitive drum 30, a charging device 32 for charging the surface of the photosensitive drum 30 in order from the upstream side in the rotation direction of the photosensitive drum 30, and the surface of the charged photosensitive drum 30 are exposed to expose the photosensitive drum 30. An exposure head 34 as an exposure device that forms an electrostatic latent image on the surface of the drum 30; a developing device 36 that develops the electrostatic latent image formed on the surface of the photosensitive drum 30 to form a toner image; and a toner A removing device 40 that removes toner remaining on the surface of the photosensitive drum 30 after the image is transferred to the intermediate transfer belt 24 is provided.

  The photosensitive drum 30, the charging device 32, the exposure head 34, the developing device 36, and the removing device 40 are accommodated in the image forming units 22C, 22M, 22Y, and 22K and unitized. The image forming units 22 </ b> C, 22 </ b> M, 22 </ b> Y, and 22 </ b> K are process cartridges that are detachably provided in the apparatus housing 11 and can be replaced.

  The photosensitive drum 30, the charging device 32, the exposure head 34, the developing device 36, and the removing device 40 do not have to be unitized. For example, at least one of the photosensitive drum 30, the charging device 32, and the developing device 36 and the exposure head 34 may be accommodated in the image forming units 22C, 22M, 22Y, and 22K and unitized.

  The intermediate transfer belt 24 is supported by a counter roll 42, a drive roll 44, and a support roll 46 that face the secondary transfer roll 28, and circulates in one direction (counterclockwise in FIG. 1) while being in contact with the photosensitive drum 30. It is supposed to move.

  The primary transfer roll 26 faces the photosensitive drum 30 with the intermediate transfer belt 24 interposed therebetween. Between the primary transfer roll 26 and the photosensitive drum 30, a primary transfer position where the toner image on the photosensitive drum 30 is primarily transferred to the intermediate transfer belt 24 is formed. At the primary transfer position, the primary transfer roll 26 transfers the toner image on the surface of the photoconductive drum 30 to the intermediate transfer belt 24 by a pressing force and an electrostatic force.

  The secondary transfer roll 28 faces the opposing roll 42 with the intermediate transfer belt 24 interposed therebetween. A secondary transfer position where the toner image on the intermediate transfer belt 24 is secondarily transferred to the recording medium P is formed between the secondary transfer roll 28 and the opposing roll 42. At this secondary transfer position, the secondary transfer roll 28 transfers the toner image on the surface of the intermediate transfer belt 24 to the recording medium P by a pressure contact force and an electrostatic force.

  The transport unit 16 includes a feed roll 50 that feeds the recording medium P accommodated in the recording medium storage unit 12, and a transport roll pair 52 that transports the recording medium P sent by the feed roll 50 to the secondary transfer position. ing.

  The fixing device 18 is disposed downstream in the transport direction from the secondary transfer position, and fixes the toner image transferred at the secondary transfer position to the recording medium P.

  A conveyance belt 54 as an example of a conveyance member that conveys the recording medium P to the fixing device 18 is disposed downstream of the secondary transfer position in the conveyance direction and upstream of the fixing device 18 in the conveyance direction.

  With the above configuration, in the image forming apparatus 10 according to the present embodiment, the recording medium P sent out from the recording medium storage unit 12 is first sent to the secondary transfer position by the transport roll pair 52.

  On the other hand, the toner images of the respective colors formed by the image forming units 22C, 22M, 22Y, and 22K are superimposed on the intermediate transfer belt 24 to form a color image. The color image formed on the intermediate transfer belt 24 is transferred to the recording medium P sent to the secondary transfer position.

  The recording medium P to which the toner image is transferred is conveyed to the fixing device 18, and the transferred toner image is fixed by the fixing device 18. The recording medium P on which the toner image is fixed is discharged to a recording medium discharge unit (not shown). As described above, a series of image forming operations are performed.

  The configuration of the image forming apparatus is not limited to the above-described configuration. For example, a direct transfer type image forming apparatus that does not have an intermediate transfer member may be used, and various configurations may be employed.

(Configuration of exposure head 34)
Next, the configuration of the exposure head 34 will be described. 2, 3 and 5 are schematic views showing the arrangement of the exposure head 34 according to this embodiment.

  As shown in FIGS. 2, 3, and 5, each exposure head 34 includes a substrate 60, an organic EL light emitting unit 62 that emits light by organic EL (electroluminescence), and light emitted from the organic EL light emitting unit 62. A scanning-capable opening member 68 having an opening 68A through which the light passes, and an imaging unit 69 that forms an image of the emitted light that has passed through the opening 68A of the opening member 68 at a predetermined position.

  The substrate 60 is formed in a long shape elongated in the main scanning direction X. Moreover, the board | substrate 60 is formed with the board | substrate which has insulation, for example, is comprised with the glass substrate or the resin substrate.

(Configuration of the organic EL light emitting unit 62)
First, the configuration of the organic EL light emitting unit 62 will be described.

  The organic EL light emitting unit 62 is provided on the substrate 60 and has a single organic EL element 70. The organic EL element 70 is formed in a linear shape along the longitudinal direction of the substrate 60 and is used as a linear light source. The organic EL element 70 has a length equal to or longer than the image forming area of the photosensitive drum 30.

  The configuration of the organic EL element 70 includes a bottom emission type organic EL element that extracts light generated from the light emitting layer 72 described later from the substrate 60 side, and light generated from the light emitting layer 72 described later from the side opposite to the substrate 60. There is a top emission type organic EL element to be taken out.

  The top emission type organic EL element 70A will be described below. FIG. 4 is a schematic diagram showing a configuration of a top emission type organic EL element 70A.

  As shown in FIG. 4, the organic EL element 70A includes an anode 71, a cathode 73 paired with the anode 71, a light emitting layer 72 disposed between the anode 71 and the cathode 73, a reflective layer 74, and a positive layer. A hole injection layer 76 and a sealing layer 75 are provided.

  The anode 71, the cathode 73, the light emitting layer 72, the reflective layer 74, the hole injection layer 76, and the sealing layer 75 are the reflective layer 74, the anode 71, the hole injection layer 76, the light emitting layer 72, the cathode 73, and the sealing layer 75. Are stacked on the substrate 60 in this order.

  The top emission type organic EL element 70A may have a configuration without the hole injection layer 76, the reflective layer 74, and the sealing layer 75. At least the anode 71, the cathode 73, the light emitting layer 72, and It is only necessary to have the third electrode 79.

  The reflective layer 74 is formed on the surface of the substrate 60. The reflection layer 74 reflects light from the light emitting layer 72 toward the light emitting layer 72. For the reflective layer 74, for example, Al, Ag, Mo, W, Ni, Cr, or the like is used. The material of the reflective layer 74 is not limited to the above. The thickness of the reflective layer 74 is 150 nm, for example. Note that the thickness of the reflective layer 74 is not limited to this.

The anode 71 is formed on the surface of the reflective layer 74. For the anode 71, for example, a conductive metal oxide such as SnO ₂ , In ₂ O ₃ , ITO, or IZO: Al is used. The material of the anode 71 is not limited to the above. Further, the thickness of the anode 71 is, for example, 100 nm. The thickness of the anode 71 is not limited to this.

  In the organic EL element 70A, the anode 71 takes out light generated from the light emitting layer 72 from the side opposite to the substrate 60. Therefore, the anode 71 does not need to have a light transmitting property.

  In the hole injection layer 76, holes are injected from the anode 71 side by applying a voltage between the cathode 73 and the anode 71. Examples of the hole injection layer 76 include low molecular weight materials such as phthalocyanines (including CuPc) or indanthrene compounds, MTDATA (4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) tri (Phenylamine), polyaniline, polymer materials such as PEDOT / PSS (polyethylenedioxythiophene / polystyrene sulfonate), etc. The material of the hole injection layer 76 is not limited to the above. The thickness of the hole injection layer 76 is, for example, 30 nm, but the thickness of the hole injection layer 76 is not limited to this, and the thickness of the hole injection layer 76 and the anode 71 is not limited thereto. A hole transport layer or the like may be disposed between them in order to increase the hole injection efficiency.

  Electrons are injected into the light emitting layer 72 from the cathode 73 side by applying a voltage between the cathode 73 and the anode 71. In addition, holes injected into the hole injection layer 76 move to the light emitting layer 72, and the holes and electrons are combined by the light emitting layer 72, whereby the light emitting layer 72 emits light.

  As the light-emitting layer 72, a chelate-type organometallic complex, a polynuclear or condensed aromatic ring compound, a perylene derivative, a coumarin derivative, a styrylarylene derivative, a silole derivative, an oxazole derivative, an oxathiazole derivative, an oxadiazole derivative, a polyparaphenylene derivative, Examples include polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyacetylene derivatives. The material of the light emitting layer 72 is not limited to the above. The thickness of the light emitting layer 72 is, for example, 50 nm. In addition, the thickness of the light emitting layer 72 is not restricted to this.

  The cathode 73 is transmissive to transmit light, and allows light generated from the light emitting layer 72 to be extracted from the side opposite to the substrate 60. In the present embodiment, the cathode 73 includes a first layer 73X and a second layer 73Y. The first layer 73X is disposed on the light emitting layer 72 side, and is made of, for example, Ca. The second layer 73Y is disposed on the side opposite to the light emitting layer 72, and is made of, for example, Al. Further, the thickness of the first layer 73X is, for example, 20 nm, and the thickness of the second layer 73Y is, for example, several tens of nm. The thicknesses of the first layer 73X and the second layer 73Y are not limited to this.

Further, the cathode 73 may be composed of a single layer. The material of the cathode 73 is not limited to the above, and for example, a conductive metal oxide such as SnO ₂ , In ₂ O ₃ , ITO, or IZO: Al may be used. Further, an electron injection layer or an electron transport layer for increasing electron injection efficiency may be disposed between the cathode 73 and the light emitting layer 72. A sealing layer 75 is formed on the surface of the cathode 73.

  Although the top emission type organic EL element 70A has been described as the organic EL element 70, the organic EL element 70 may be a bottom emission type organic EL element. In the bottom emission type organic EL element, the anode 71, the cathode 73, the light emitting layer 72, the reflective layer 74, the hole injection layer 76 and the sealing layer 75 are the anode 71, hole injection layer 76, light emitting layer 72, cathode 73. The reflective layer 74 and the sealing layer 75 are laminated on the substrate 60 in this order. In addition, the anode 71 and the substrate 60 on the emission light emission side need to be transparent to transmit the emission light.

(Configuration of the emission side of the organic EL light emitting unit 62)
Next, the configuration on the emission side of the organic EL light emitting unit 62 will be described.

  As shown in FIG. 5, an opening member 68 and an imaging unit 69 are disposed between the organic EL light emitting unit 62 and the photosensitive drum 30 on the emission side of the organic EL light emitting unit 62.

  The image forming unit 69 includes a lens array 64 as an example of an image forming element array that forms an image of the light emitted from the organic EL light emitting unit 62 on the surface of the photosensitive drum 30. The lens array 64 is configured by arranging a plurality of rod lenses 64A as an example of an imaging element. By forming the light emitted from the organic EL element 70 on the photosensitive drum 30, the photosensitive drum 30 is exposed to form a latent image.

  The imaging unit 69 is not limited to the lens array 64, and can have various configurations. As the imaging unit 69, for example, a cylindrical lens may be used.

  The opening member 68 is formed with a single opening 68A. In the opening 68A, the light emitted from the organic EL light emitting unit 62 passes through the opening 68A, and the light emitted from the organic EL light emitting unit 62 is shielded at other portions.

  The opening member 68 is provided with a moving mechanism 65 that moves the opening member 68 along the main scanning direction (the axial direction of the photosensitive drum 30). The moving mechanism 65 is configured using a mechanical element such as a ball screw or a belt.

  The moving mechanism 65 moves the opening member 68 to move the opening 68A, so that the photosensitive drum 30 is exposed successively and sequentially along its axial direction.

  The moving mechanism 65 is provided with a control circuit 67 that controls the movement of the opening member 68. The control circuit 67 controls the movement and stop of the opening member 68 and the movement speed.

  Further, as shown in FIG. 2, the substrate 60 is provided with a single drive circuit 66 for driving the organic EL light emitting unit 62. The drive circuit 66 controls the light emission of the organic EL light emitting unit 62. Light emission control includes lighting / extinguishing (ON / OFF) control and light emission intensity control.

  For example, when the organic EL light-emitting unit 62 is turned on / off and the light emission intensity is controlled by the drive circuit 66, the control circuit 67 controls the opening member 68 to move at a constant speed, and is necessary for the photosensitive drum 30. You may make it obtain a sufficient exposure amount. When the organic EL light-emitting unit 62 is controlled to be turned on / off at a constant light intensity by the drive circuit 66, the control circuit 67 changes the moving speed of the opening member 68 to the photosensitive drum 30. The necessary exposure amount may be obtained. In addition, the drive circuit 66 may control the turning on / off of the organic EL light emitting unit 62 and the light emission intensity, and the control for changing the moving speed of the opening member 68 may be synchronized.

  As described above, in the configuration of this embodiment, since there is only one light emitting element, only one drive circuit 66 is required to drive the light emitting element, which causes a problem of variation in light emission characteristics between the light emitting elements. Hateful. Further, a pair of correction circuits for maintaining a constant light amount with deterioration of the light emitting element is sufficient, and the circuit scale is reduced. Along with this, the mounting cost is also reduced.

(Modification 1)
Next, the configuration of Modification Example 1 will be described. FIG. 6 is a schematic side view showing the configuration of the exposure head according to the first modification.

  In the configuration of Modification 1, as shown in FIG. 6, the organic EL light emitting unit 62 is configured by dividing an organic EL element, and a plurality of linear organic EL elements 70 are arranged at predetermined intervals. Configured.

  A plurality of openings 68A are formed in the opening member 68, and each of the openings 68A allows light emitted from the plurality of organic EL elements 70 to pass therethrough. Specifically, the number of openings 68 </ b> A is the same as the number of organic EL elements 70. In addition, a drive circuit 66 that drives the organic EL elements 70 is provided in each organic EL element 70.

  According to the configuration of the first modification, the exposure area per light emitting element is limited, and the scanning range of the opening 68A of the opening member 68 is reduced. Thereby, compared with the structure with one organic EL element 70, an exposure speed becomes quick.

(Modification 2)
Next, the configuration of Modification Example 2 will be described. FIG. 7 is a schematic side view showing a configuration of an exposure head according to the second modification.

  In Modification 2, as shown in FIG. 7, a condensing lens 86 as an example of a condensing member that condenses the light emitted from the organic EL light emitting unit 62 is disposed in the opening 68 </ b> A of the opening member 68. .

  In the configuration having a large number of organic EL elements corresponding to the number of pixels, the number of condensing lenses is required, whereas in the second modification, only one condensing lens 86 is required.

  Thereby, the exposure head 34 becomes an inexpensive structure. Further, since only one condensing lens 86 is required, the problem of variation in condensing characteristics between the condensing lenses hardly occurs. Note that the configuration of Modification 2 may be combined with the configuration of Modification 1.

(Modification 3)
Next, the configuration of Modification Example 3 will be described. FIG. 8 is a schematic side view showing the configuration of the exposure head according to the third modification.

  In Modification 3, as shown in FIG. 8, a rod lens 64 </ b> A as an imaging lens that forms an image of the emitted light from the organic EL light emitting unit 62 on the photosensitive drum 30 is disposed in the opening 68 </ b> A of the opening member 68. ing.

  In the configuration of the modification 3, the imaging lens array is not necessary, so that the exposure head 34 is inexpensive. In addition, since only one rod lens 64A is required, the problem of variation in imaging characteristics between the imaging lenses hardly occurs. Note that the configuration of Modification 3 may be combined with the configuration of Modification 1.

(Evaluation)
In the configuration and modification examples 1 to 3 of the above embodiment and Comparative Examples 1 and 2 below, the average light amount per element on the imaging plane and the measured light amount when the light emitting element emits light with the same light amount The evaluation was compared with the estimated manufacturing cost. The variation in the measured light amount was determined by the difference between the minimum value and the maximum value of the light amount on the imaging plane.

(Comparative Example 1)
In Comparative Example 1, as shown in FIG. 9, an organic EL element 104 juxtaposed on a substrate 102 over a full exposure width at a predetermined resolution, and light emitted from the organic EL element 104 is used as a photosensitive drum. And an imaging lens array 106 that forms an image on each of them 30. The organic EL element 104 is provided with a drive circuit for driving each.

(Comparative Example 2)
Comparative Example 2 has a configuration in which a condensing lens 108 is arranged in each organic EL element 104 as shown in FIG.

  As a result, as shown in FIG. 11, it was found that Embodiments and Modifications 1 to 3 have less variation in light amount and are less expensive than Comparative Examples 1 and 2. In addition, among the embodiments and the first to third modifications, the third modification is found to be particularly low in light quantity variation and low cost. The present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements can be made.

10 Image forming apparatuses 22C, 22M, 22Y, 22K Image forming unit 30 Photosensitive drum (image holding body)
34 exposure head 36 developing device 62 organic EL light emitting unit 68A opening 68 opening member 69 imaging unit 70 organic EL element 86 condensing lens (condensing member)

Claims (7)

A substrate,
An organic EL light-emitting unit that is provided on the substrate and emits light by organic EL;
A scannable opening member having an opening through which light emitted from the organic EL light emitting unit passes;
An imaging unit that forms an image of light emitted through the opening of the aperture member at a predetermined position;
With
An exposure head that controls the light emission intensity for each part in the scanning direction in the imaging target on which the light emission is imaged by the imaging unit by changing the scanning speed of the aperture member . The organic EL light emitting unit has a plurality of organic EL elements arranged at predetermined intervals,
The exposure head according to claim 1, wherein the opening member has an opening through which light emitted from the plurality of organic EL elements passes.   The exposure head according to claim 1, further comprising a condensing member that is disposed in the opening and condenses light emitted from the organic EL light emitting unit.   The exposure head according to claim 1, wherein the imaging unit is disposed in the opening.   The exposure head according to claim 1, wherein the organic EL light emitting unit is driven in synchronization with scanning of the opening member. At least one of a latent image holding body that holds a latent image, a charging device that charges the latent image holding body, and a developing device that develops the latent image of the latent image holding body;
The exposure head according to claim 4, wherein the latent image is formed by irradiating the latent image holding member with light;
A cartridge detachably attachable to the image forming apparatus. A latent image holding body for holding the latent image;
The exposure head according to claim 4, wherein the latent image is formed by irradiating the latent image holding member with light;
A developing device for developing a latent image formed by the exposure head;
An image forming apparatus comprising:

Images