Image formation apparatus

Abstract

To provide an image formation apparatus capable of performing static elimination so as to cover a portion used for image formation.SOLUTION: An image formation apparatus comprises a photosensitive drum and a panel member 12a disposed to face the photosensitive drum and having a plurality of light-emitting elements. The plurality of light-emitting elements include an image exposure section 41 that performs exposure on the photosensitive drum for image formation, and a static elimination section 42 that performs static elimination. The static elimination section 42 has a larger area where the photosensitive drum is exposed than that by the image exposure section 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus including a panel member having a plurality of light emitting elements. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses have been widely used, which form an electrostatic latent image on a photosensitive member using a laser beam or the like, and then develop, transfer, and fix the electrostatic latent image to form an image on paper. In recent years, linear light sources, in which point light sources such as light-emitting elements are arranged in a line, have been used as the light source for exposing the photosensitive member. Furthermore, image forming apparatuses sometimes use linear light sources in static elimination processes, and a method has been proposed for reducing the current consumption in such cases (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-173555 Summary of the Invention [Problem to be solved by the invention]

[0004] A conventional image forming apparatus forms an electrostatic latent image on a photosensitive member by controlling the light emission of a light source device configured with a plurality of light-emitting elements arranged in a line, and includes an image information acquisition unit that acquires image information, and a light source control unit that controls the light emission based on the image information and performs a discharge process to remove charge from the photosensitive member, and when controlling the light emission in the discharge process, the light source control unit turns off some of the plurality of light-emitting elements and makes the light emission time in one light emission control longer than the light emission time in the light emission control for forming an electrostatic latent image.

[0005] In the image forming apparatus described above, the entire surface of the photoconductor is exposed by increasing the light emission time and the amount of exposure, but this increases the processing time for the static elimination process, which is a problem. Therefore, a different method is required to eliminate static from the entire surface of the photoconductor.

[0006] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an image forming apparatus that can eliminate static electricity so as to cover the portion used for image formation. [Means for solving the problem]

[0007] The image forming apparatus according to the present disclosure is an image forming apparatus comprising a photosensitive body and a panel member facing the photosensitive body and having a plurality of light-emitting elements, wherein the plurality of light-emitting elements include an image exposure section that exposes the photosensitive body to form an image, and a discharge section that discharges electricity, and wherein the discharge section has a larger area for exposing the photosensitive body than the image exposure section.

[0008] In the image forming apparatus according to the present disclosure, the static eliminator may be configured to have a length longer in an axial direction along the rotation axis of the photosensitive member than the image exposure unit.

[0009] In the image forming apparatus according to the present disclosure, the static eliminating section and the image exposure section may be arranged adjacent to each other in a direction perpendicular to the axial direction.

[0010] In the image forming apparatus according to the present disclosure, the panel member may be configured to be bent so that a surface on which the image exposure unit is provided and a surface on which the static eliminator is provided intersect with each other.

[0011] In the image forming apparatus according to the present disclosure, the discharge units may be arranged adjacent to both ends of the image exposure unit in the axial direction, sandwiching the image exposure unit therebetween, and the image exposure unit may be configured to perform discharge together with the discharge units.

[0012] In the image forming apparatus according to the present disclosure, the image exposure section may be configured with a plurality of rows of the light emitting elements arranged adjacent to each other in a direction perpendicular to the axial direction. [Effects of the Invention]

[0013] According to the present disclosure, in addition to an image exposure section, which is a group of pixels that form an image, a discharge section that has a larger area for exposing the photosensitive member than the image exposure section is provided on the same panel member, so that discharge can be performed to cover the area used for image formation. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view showing a configuration of an image forming apparatus according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic plan view showing a panel member according to the first embodiment of the present disclosure. [Figure 3] FIG. 10 is a schematic plan view showing a panel member according to a second embodiment of the present disclosure. [Figure 4] FIG. 10 is a schematic plan view showing a panel member according to a third embodiment of the present disclosure. [Figure 5] FIG. 10 is a schematic plan view showing a panel member according to a fourth embodiment of the present disclosure. [Figure 6] FIG. 13 is a schematic side view showing the positional relationship between a photosensitive drum and a panel member in a fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] (First embodiment) Hereinafter, an image forming apparatus according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0016] FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to a first embodiment of the present disclosure.

[0017] The image forming device 100 is a multifunction device having a copy function, a scanner function, a facsimile function, and a printer function, and transmits an image of a document read by the image reading device 130 to an external device, and forms an image of a document read by the image reading device 130 or an image received from an external device in color or monochrome on a recording medium such as paper.

[0018] An original transport device 110 that is supported so as to be able to open and close freely is provided above the image reading device 130. The original transport device 110 transports one or more originals one by one. The image reading device 130 scans a scanning optical system 130b to read an original placed on an original placement table 130a, or reads an original transported by the original transport device 110 to generate image data.

[0019] The image forming apparatus 100 is provided with a fixing device 1, a developing device 2, a photosensitive drum 3 (an example of a photosensitive body), a drum cleaning device 4, a charger 5, an intermediate transfer belt device 7, a secondary transfer device 11, an exposure device 12, and a paper feed section 18.

[0020] Image forming apparatus 100 handles image data corresponding to color images using black (K), cyan (C), magenta (M), and yellow (Y), or monochrome images using a single color (e.g., black). Image forming apparatus 100 is provided with four developing devices 2, four photosensitive drums 3, four drum cleaning devices 4, and four chargers 5 for forming four types of toner images, and four image stations Pa, Pb, Pc, and Pd are configured corresponding to black, cyan, magenta, and yellow, respectively.

[0021] The charger 5 uniformly charges the surface of the photosensitive drum 3 to a predetermined potential. The exposure device 12 has a panel member 12a facing the surface of the photosensitive drum 3 and exposes the surface of the photosensitive drum 3 to light to form an electrostatic latent image. In FIG. 1, the panel member 12 is schematically shown spaced a predetermined distance from the surface of the photosensitive drum 3. This distance is appropriately set depending on the resolution of the electrostatic latent image and the light intensity of the panel member 12a, ranging from a position close to the surface of the photosensitive drum 3 to a position far away. The developing device 2 develops the electrostatic latent image on the surface of the photosensitive drum 3 to form a toner image on the surface of the photosensitive drum 3. The drum cleaning device 4 removes and collects residual toner from the surface of the photosensitive drum 3. Through the above-described series of operations, a toner image of each color is formed on the surface of each photosensitive drum 3. The panel member 12a will be described in detail later with reference to FIG. 2.

[0022] The intermediate transfer belt device 7 includes an intermediate transfer roller 6, an endless intermediate transfer belt 71, an intermediate transfer drive roller 72, an intermediate transfer driven roller 73, and a cleaning device 9. Four intermediate transfer rollers 6 are provided inside the intermediate transfer belt 71 so as to form four types of toner images corresponding to each color. The intermediate transfer rollers 6 transfer the toner images of each color formed on the surface of the photosensitive drum 3 onto the intermediate transfer belt 71, which moves around in a circular motion.

[0023] The intermediate transfer belt 71 is stretched over an intermediate transfer drive roller 72 and an intermediate transfer driven roller 73. In the image forming apparatus 100, the toner images of each color formed on the surface of each photosensitive drum 3 are sequentially transferred and superimposed to form a color toner image on the surface of the intermediate transfer belt 71. The cleaning device 9 removes and collects waste toner remaining on the surface of the intermediate transfer belt 71 without being transferred to paper.

[0024] The secondary transfer device 11 sandwiches and transports a sheet of paper transported through the paper transport path 21 in the transfer nip portion TN between the secondary transfer roller 11a and the intermediate transfer belt 71. When the sheet of paper passes through the transfer nip portion TN, the toner image on the surface of the intermediate transfer belt 71 is transferred onto the sheet of paper, and the sheet of paper is transported to the fixing device 1.

[0025] The fixing device 1 includes a fixing belt 31 that rotates around an axis and a pressure roller 32. The fixing device 1 sandwiches a sheet of paper onto which a toner image has been transferred in a nip portion N between the fixing belt 31 and the pressure roller 32, and applies heat and pressure to fix the toner image to the sheet. Although not shown in FIG. 1, the fixing device 1 may include components other than the fixing belt 31 and the pressure roller 32.

[0026] The paper feed unit 18 includes a paper feed cassette that holds recording media (paper) used for image formation, and is provided below the exposure device 12. The paper is pulled out of the paper feed unit 18 by a pickup roller 16 and transported to a paper transport path 21. The paper transported to the paper transport path 21 passes through the secondary transfer device 11 and the fixing device 1, and is then discharged to a paper output tray 19 by a discharge roller 17.

[0027] Conveyance rollers 13, registration rollers 14, and discharge rollers 17 are arranged on paper conveyance path 21. Conveyance rollers 13 facilitate the conveyance of paper. Registration rollers 14 convey paper at a speed equal to the process speed at which an image is formed on the paper. Registration rollers 14 are provided between paper feed unit 18 and secondary transfer device 11, and adjust the timing of paper conveyance so that the toner image is transferred to the paper by secondary transfer device 11. For example, registration rollers 14 wait (temporarily stop) while clamping paper conveyed from paper feed unit 18, and then start conveying the paper at a constant speed in synchronization with secondary transfer device 11.

[0028] When an image is to be formed on the back side of the paper in addition to the front side, the conveying direction of the paper is changed by discharge rollers 17, and the paper is conveyed to reversing conveying path 22. In reversing conveying path 22, the paper is guided up to registration rollers 14 in a reversed state by reversing conveying rollers 15. Image forming apparatus 100 forms an image on the back side of the paper guided to registration rollers 14 in the same manner as on the front side, and discharges the paper to discharge tray 19.

[0029] FIG. 2 is a schematic plan view showing a panel member according to the first embodiment of the present disclosure.

[0030] In the image exposure unit 41, four panel members 12a are provided so as to face the four photosensitive drums 3, respectively. The four panel members 12a have substantially the same configuration, and therefore, in FIG. 2, one panel member 12a is extracted and shown schematically.

[0031] The panel member 12a has multiple light-emitting elements, which constitute an image exposure unit 41 that exposes the photosensitive drum 3 and a static elimination unit 42 that eliminates static electricity. Although not shown, an optical element such as a lens may be disposed between the photosensitive drum 3 and the panel member 12a so that light emitted from the light-emitting elements forms an image on the photosensitive drum 3. The optical element may be disposed in various positions corresponding to the image exposure unit 41 and the static elimination unit 42, or may be disposed as an integrated optical element corresponding to each, or may be disposed in a position corresponding to only one of the units. The image exposure unit 41 exposes pixels based on image data to form an electrostatic latent image on the surface of the photosensitive drum 3. The static elimination unit 42 performs a static elimination process by irradiating the surface of the photosensitive drum 3 with light to remove electrical charges from the photosensitive drum 3.

[0032] In the image forming apparatus 100, the axial direction W along the rotation axis of the photosensitive drum 3 is parallel to the width direction of the paper on which an image is formed, and the photosensitive drum 3 is configured to rotate around the axis of the rotation axis. The panel member 12a is a rectangular flat plate, and its longitudinal direction corresponds to the axial direction W and its lateral direction corresponds to the rotation direction R of the photosensitive drum 3.

[0033] In the panel member 12a, the static eliminator 42 and the image exposure unit 41 are disposed adjacent to each other in a direction (rotational direction R) perpendicular to the axial direction W. Specifically, the static eliminator 42 is provided at two locations sandwiching the image exposure unit 41 in the rotational direction R. In other words, the static eliminator 42, the image exposure unit 41, and the static eliminator 42 are disposed in this order along the rotational direction R.

[0034] The image exposure section 41 is composed of a plurality of light-emitting elements (exposure elements 41a) arranged side by side in the axial direction W. In the following, in order to distinguish between some of the light-emitting elements, the light-emitting elements that make up the image exposure section 41 may be referred to as exposure elements 41a. The exposure element 41a corresponds to one pixel in the image data, and the image exposure section 41 may be provided with a number of exposure elements 41a corresponding to the pixel size of the image to be formed.

[0035] The static eliminator 42 is configured to have a length in the axial direction W that is longer than that of the image exposure unit 41. Specifically, the static eliminator 42 is disposed opposite the image exposure unit 41 in the rotational direction R and extends outward beyond both ends of the image exposure unit 41 in the axial direction W. While FIG. 2 illustrates the static eliminator 42 as an integral unit that is long in the axial direction W, this is not limiting and the static eliminator 42 may be configured as a plurality of light-emitting elements. That is, the static eliminator 42 may be configured such that a plurality of light-emitting elements are arranged in the axial direction W and operate in unison. Furthermore, the length of the static eliminator 42 in the rotational direction R of the photosensitive drum 3 may be the same as or different from that of the exposure element 41a. Increasing the length of the static eliminator 42 in the rotational direction R allows for a longer static elimination time, i.e., a longer static elimination period.

[0036] In the image forming apparatus 100, the photosensitive drum 3 is rotated while the surface of the photosensitive drum 3 is exposed to light emitted from the panel member 12a, and when comparing the areas of the photosensitive drum 3 exposed by the image exposure unit 41 and the discharge unit 42, the length in the axial direction W is more important than the length in the rotational direction R.

[0037] In this embodiment, the charge removal unit 42 is longer than the image exposure unit 41 in the axial direction W, which corresponds to the main scanning direction. The charge removal unit 42, which has a larger area for exposing the photosensitive drum 3 than the image exposure unit 41, is provided on the same panel member 12a as the image exposure unit 41, which is a group of pixels that form an image. Therefore, charge removal can be performed to cover the area used for image formation. Therefore, the pixel size can be reduced so that the minimum necessary area is exposed. Furthermore, by arranging the charge removal unit 42 and the image exposure unit 41 adjacent to each other, the surface of the panel member 12a can be used efficiently, allowing the panel member 12a to be made smaller.

[0038] In image forming apparatus 100, a series of image formations is processed as one job regardless of whether the number of sheets is one or multiple, and static elimination can be performed appropriately when the job is completed. Static elimination unit 42 may be configured with light-emitting elements having the same specifications as image exposure unit 41, and the output can be controlled so that the exposure for image formation and the exposure for static elimination are appropriate.

[0039] In the panel member 12a, active matrix wiring may be connected to a plurality of light emitting elements, and appropriate light emitting elements may be driven via these wirings. The static eliminator 42 may be controlled together with the image exposure unit 41 as one pixel in the active matrix system, or may be provided with wiring so as to be controlled by a drive circuit separate from the image exposure unit 41.

[0040] (Second embodiment) Next, an image forming apparatus according to a second embodiment of the present disclosure will be described with reference to the drawings. In the second embodiment, the configuration of the panel member 12a is different from that of the first embodiment. Note that the second embodiment has a configuration substantially similar to that of the first embodiment shown in Figures 1 and 2, so a description thereof will be omitted and only the differences will be described.

[0041] FIG. 3 is a schematic plan view showing a panel member according to the second embodiment of the present disclosure.

[0042] The second embodiment differs from the first embodiment in the arrangement of the image exposure unit 41 and the static eliminator 42 on the panel member 12a. Specifically, the static eliminators 42 are arranged adjacent to both ends of the image exposure unit 41 in the axial direction W, sandwiching the image exposure unit 41 therebetween. In this embodiment, the static eliminator 42, image exposure unit 41, and static eliminator 42 are arranged in this order along the axial direction W, and on the panel member 12a, multiple light-emitting elements are arranged in a row in the axial direction W. Furthermore, the image exposure unit 41 is controlled to perform static elimination together with the static eliminator 42. In other words, during static elimination, the image exposure unit 41 functions as the static eliminator 42. In this way, by also using the image exposure unit 41 as the static eliminator 42, the portion that only performs static elimination can be made as small as possible, thereby enabling the panel member 12a to be made more compact.

[0043] (Third embodiment) Next, an image forming apparatus according to a third embodiment of the present disclosure will be described with reference to the drawings. In the third embodiment, the configuration of the panel member 12a is different from that of the first and second embodiments. Note that the third embodiment has substantially the same configuration as the first and second embodiments shown in FIGS. 1 to 3, so a description thereof will be omitted and only the differences will be described.

[0044] FIG. 4 is a schematic plan view showing a panel member according to the third embodiment of the present disclosure.

[0045] The third embodiment differs from the first embodiment in the arrangement of the image exposure unit 41 on the panel member 12a. Specifically, the image exposure unit 41 is composed of multiple rows of exposure elements 41a arranged adjacent to each other in the rotation direction R. That is, in the image exposure unit 41, multiple rows of exposure elements 41a aligned in the axial direction W are arranged in the rotation direction R (four rows in FIG. 4). In this way, by providing multiple rows of light-emitting elements (exposure elements 41a) as the image exposure unit 41, exposure can be performed efficiently, thereby speeding up processing.

[0046] In this embodiment, as in the first embodiment, the static elimination section 42 is provided at two locations in the rotational direction R, sandwiching the image exposure section 41 therebetween, and in the axial direction W, extends beyond both ends of the image exposure section 41.

[0047] (Fourth embodiment) Next, an image forming apparatus according to a fourth embodiment of the present disclosure will be described with reference to the drawings. In the fourth embodiment, the configuration of the panel member 12a is different from that of the first to third embodiments. Note that the fourth embodiment has substantially the same configuration as the first to third embodiments shown in FIGS. 1 to 4, so a description thereof will be omitted and only the differences will be described.

[0048] FIG. 5 is a schematic plan view showing a panel member according to the fourth embodiment of the present disclosure.

[0049] The fourth embodiment differs from the third embodiment in the arrangement of the static eliminators 42 on the panel member 12a. Specifically, similar to the second embodiment, the static eliminators 42 are arranged adjacent to both ends of the image exposure unit 41 in the axial direction W, with the image exposure unit 41 sandwiched therebetween. Furthermore, the range in which the static eliminators 42 are provided in the rotational direction R is substantially the same as that of the image exposure unit 41. While FIG. 5 shows the static eliminators 42 that are long and integrally connected in the axial direction W and the rotational direction R, the present invention is not limited thereto, and the static eliminators 42 may be configured such that a plurality of light-emitting elements are arranged side by side in the axial direction W and the rotational direction R, and the plurality of light-emitting elements operate in unison.

[0050] In this embodiment, the image exposure unit 41 is controlled to perform static elimination together with the static eliminator 42, as in the second embodiment, and the image exposure unit 41 functions as the static eliminator 42 during static elimination.

[0051] (Fifth embodiment) Next, an image forming apparatus according to a fifth embodiment of the present disclosure will be described with reference to the drawings. The fifth embodiment differs from the first to fourth embodiments in the configuration of the panel member 12a. Note that the fifth embodiment has substantially the same configuration as the first to fourth embodiments shown in FIGS. 1 to 5, so a description thereof will be omitted and only the differences will be described.

[0052] 6 is a schematic side view showing the positional relationship between the photosensitive drum 3 and the panel member 12a in the image forming apparatus 100 in consideration of ease of viewing the drawing.

[0053] In the fifth embodiment, on the panel member 12a, as in the first and third embodiments, the static eliminator 42 and the image exposure unit 41 (exposure elements 41a) are arranged adjacent to each other in the rotation direction R. The panel member 12a is bent so that the surface on which the image exposure unit 41 is provided intersects with the surface on which the static eliminator 42 is provided. By bending the panel member 12a between the image exposure unit 41 and the static eliminator 42 in this way, the image exposure unit 41 and the static eliminator 42 can each be directly opposed to the circumferential surface of the photosensitive drum 3.

[0054] 6 simply shows the panel member 12a in which a boundary between the image exposure unit 41 and the static eliminator 42 is provided in one location in the rotation direction R, but this is not limited thereto, and if there are boundaries between the image exposure unit 41 and the static eliminator 42 in two or more locations, multiple folds may be provided to bend the panel member 12a. Furthermore, it is sufficient that the light-emitting elements provided on the panel member 12a directly face the circumferential surface of the photosensitive drum 3, and the orientation of the light-emitting elements may be adjusted by bending the panel member 12a so that it fits along the circumferential surface of the photosensitive drum 3.

[0055] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0056] 3 Photoconductor drum (an example of a photoconductor) 12 Exposure equipment 12a Panel member 41 Image exposure section 41a Exposure element 42 Static elimination unit 100 Image forming device R Rotation direction W axis direction

Claims

1. A photoreceptor; an image forming apparatus including a panel member facing the photosensitive member and having a plurality of light-emitting elements, the plurality of light-emitting elements include an image exposure unit that exposes the photosensitive member to light to form an image, and a static elimination unit that eliminates static electricity; The charge removal unit has a larger area for exposing the photosensitive member than the image exposure unit. An image forming apparatus comprising:

2. 2. The image forming apparatus according to claim 1, The static elimination unit has a length in the axial direction along the rotation axis of the photosensitive member that is longer than that of the image exposure unit. An image forming apparatus comprising:

3. 3. The image forming apparatus according to claim 2, The static eliminating unit and the image exposure unit are disposed adjacent to each other in a direction perpendicular to the axial direction. An image forming apparatus comprising:

4. 4. The image forming apparatus according to claim 3, The panel member is bent so that the surface on which the image exposure unit is provided and the surface on which the static elimination unit is provided intersect. An image forming apparatus comprising:

5. 3. The image forming apparatus according to claim 2, the static eliminators are disposed adjacent to both ends of the image exposure unit in the axial direction, with the image exposure unit sandwiched therebetween; The image exposure unit performs static elimination in conjunction with the static elimination unit. An image forming apparatus comprising:

6. 3. The image forming apparatus according to claim 2, The image exposure unit is composed of a plurality of rows of the light emitting elements arranged adjacent to each other in a direction perpendicular to the axial direction. An image forming apparatus comprising:

Images