JP2006218681A - Image printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a distance between a light-emitting element and an image carrying body at a specified dimension while various malfunctions caused by a contact between a head and the image carrying body are avoided. <P>SOLUTION: A photo-conductor drum 110 is rotated in the arrow mark A1 direction. A supporting body 31 faces the photo-conductor drum 110. A light-emitting apparatus 33 provided at a site facing to the photo-conductor drum 110 among the supporting body 31 has a plurality of the light-emitting elements 332 for forming a latent image on the photo-conductor drum 110 by light emission. A roller 35 is arranged at a site facing the photo-conductor drum 110 among the supporting body 31 so that the rotating shaft is in an approximately vertical direction to the advancing direction of the photo-conductor drum 110. A plurality of elastic bodies 41 energizes the supporting body 31 to the photo-conductor drum 110 side so that the roller 35 comes into contact with the photo-conductor drum 110. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image printing apparatus in which a latent image is formed on an image carrier in response to irradiation light from a light emitting element.

  This type of image printing apparatus includes an image carrier such as a photosensitive drum and a head facing the surface thereof. A plurality of light emitting elements formed of a light emitting material such as an organic EL (ElectroLuminescent) material are arranged in a portion of the head that faces the photosensitive drum. A latent image corresponding to the irradiation light from each light emitting element is formed on the surface of the image carrier.

In this configuration, the distance between the surface and each light emitting element may vary depending on the portion of the image carrier due to an error in the dimensions of the head or the image carrier or an error in the mounting position of these elements. When the distance between the image carrier and each light emitting element varies in this way, the area and shape of the area where the light from each light emitting element reaches on the surface of the image carrier varies. It becomes difficult to print an image. In order to solve this problem, a configuration in which a guide body that contacts the surface of the image carrier is fixed to the head (for example, Patent Document 1), or a configuration in which the end face of each light emitting element is in contact with the surface of the image carrier ( For example, Patent Document 2) has been proposed.
Japanese Patent Laid-Open No. 7-178756 (FIG. 1) Japanese Patent Laid-Open No. 5-27563 (FIG. 1)

  However, in these techniques, since the image carrier rotates while the parts (hereinafter referred to as “contact portions”) such as the guide body of Patent Document 1 and the light emitting element of Patent Document 2 are in contact with each other, The head may vibrate with driving. For example, the head is elastically deformed by the friction force acting on the contact portion from the image carrier, and the head returns to its original shape when the stress of the head exceeds a certain limit. When driven at high speed, head vibration becomes significant. Since the distance between the image carrier and each light emitting element fluctuates due to such vibration, it is difficult to irradiate a specific area of the image carrier with a predetermined amount of light even by each of the techniques described above. It is.

  Further, these surfaces are worn by friction between the head and the image carrier, and as a result, the distance between each light emitting element and the image carrier may change over time. Furthermore, for example, when a foreign substance enters a portion where the head and the image carrier are in contact with each other, there is a risk that the foreign substance is continuously pressed against the image carrier by the head and the surface thereof is damaged.

  The present invention has been made in view of such circumstances, and the distance between the light emitting element and the image carrier is set to an intended size while avoiding various problems caused by the contact between the head and the image carrier. It aims to solve the problem of maintaining.

In order to solve this problem, an image printing apparatus according to the present invention includes an image carrier that travels in one direction, a support that faces the image carrier, and a portion of the support that faces the image carrier. And a plurality of light emitting elements that form a latent image on the image carrier by light emission, and a rotation axis is directed in a direction substantially perpendicular to the traveling direction of the image carrier to a portion of the support that faces the image carrier. And a biasing means that biases the support toward the image carrier so that the roller contacts the image carrier.
According to this configuration, the support is biased toward the image carrier so that the roller comes into contact with the image carrier. Therefore, the distance between the light-emitting element provided on the support and the image carrier is accurate. Maintained at the dimensions of Further, since a roller having a rotation axis in a direction substantially perpendicular to the direction in which the image carrier travels contacts the image carrier, the roller rotates as the image carrier travels. Therefore, the vibration of the support, the light emitting element and the roller (that is, the head) supported by the support, and the wear of the portions of the image carrier and the head that are in contact with each other are suppressed. Further, even if foreign matter is sandwiched between the image carrier and the roller, the foreign matter is quickly removed by the rotation of the roller. Therefore, a situation in which the surface of the image carrier is damaged by such foreign matter is prevented.

  In a desirable mode of the present invention, the urging means is provided in a portion of the support opposite to the image carrier, and a plurality of elastic bodies that press the support (for example, the elastic body 41 in the first embodiment). including. According to this aspect, the support can be evenly biased toward the image carrier with a simple configuration. In another aspect, the urging means includes a frame member having a portion facing the side surface of the support, and an elastic body (for example, an elastic body in the second embodiment) interposed between the side surface of the support and the frame member. 42). According to this aspect, the space on the opposite side of the support from the image carrier can be reduced. Further, if the urging means includes an elastic body (for example, the elastic body 43 in the second embodiment) that presses the frame member toward the image carrier, the support can be reliably urged toward the image carrier. It becomes possible.

  In yet another embodiment, a groove extending in a direction substantially perpendicular to the advancing direction of the image carrier is formed in a portion of the support that faces the image carrier, and the roller is the image carrier of the support. The outer peripheral surface is accommodated in the groove so that a part of the outer peripheral surface protrudes from the surface facing the body toward the image carrier. According to this configuration, since the roller is partially accommodated in the groove, the thickness of the head including the support, the roller, and the light emitting element can be reduced. However, in this configuration, there is a possibility that the bottom surface of the groove and the roller come into contact with each other when the support is bent toward the roller, and this friction may prevent the roller from rotating. For this reason, the structure by which the auxiliary roller which contacts the side surface of a roller is arrange | positioned at the bottom face of a groove | channel is desirable. According to this structure, since an auxiliary roller rotates with rotation of a roller, a roller can be rotated smoothly. Of course, even if the auxiliary roller is not provided, according to the configuration in which the coefficient of friction of the surface of the support facing the roller is small, or the configuration in which the support is formed of a highly rigid material and is not easily deformed, the roller Can be smoothly rotated.

  In the desirable mode of the present invention, a plurality of rollers are arranged in each position which counters across a plurality of light emitting elements among the support. According to this aspect, the support can be pressed evenly against the image carrier, and therefore the distance between the light-emitting elements and the image carrier can be made uniform. In a configuration in which a plurality of light emitting elements are arranged in a direction substantially perpendicular to the traveling direction of the image carrier, it is desirable that each roller is opposed to the surface of the image carrier over the entire width of the image carrier. According to this configuration, not only can the intervals between the light emitting elements and the image carrier be made uniform, but the light emitted from each light emitting element is blocked by the rollers located on both sides thereof, so that the light emitted from the light emitting element is not Even in the case of diffusing, it is possible to selectively irradiate the light emitted from the light emitting element to the area between the rollers of the image carrier.

  In the present invention, an optical element may be interposed between the image carrier and the light emitting element. For example, according to a configuration in which a lens is disposed between the image carrier and the light emitting element to collect the light emitted from the light emitting element (see, for example, FIG. 11), the light emitted from the light emitting element is It is possible to efficiently reach the image carrier. In such a configuration, the area of the region where the light emitted from the light emitting element reaches significantly varies depending on the distance between the image carrier and the light emitting element. An error in the distance between the image carrier and the light emitting element that is allowed to form a latent image of the period is smaller than that in a configuration in which no lens is arranged. According to the present invention, since the distance between the image carrier and the light-emitting element can be maintained substantially constant with high accuracy, the image carrier can be used even when the lens is interposed between the light-emitting element and the image carrier. The desired latent image can be accurately formed on the surface of the film.

  Embodiments of the present invention will be described with reference to the drawings. In the following drawings, the ratio of the dimensions of each part is appropriately changed from the actual one.

<A: First Embodiment>
FIG. 1 is a perspective view illustrating a partial configuration of the image printing apparatus according to the present embodiment. This image printing apparatus is an apparatus used as a printing part of a printer, a copying machine, and a facsimile machine. As shown in FIG. 1, a cylindrical photosensitive drum 110 that is rotatably supported in the direction of an arrow A1. And a head 10 disposed so as to face the side surface of the photosensitive drum 110. Hereinafter, the direction of the rotation axis of the photosensitive drum 110 (that is, the direction of the bus line of the photosensitive drum 110 (main scanning direction)) is referred to as “drum axis direction X”.

  2 is a cross-sectional view showing a configuration when the element shown in FIG. 1 is broken along a plane perpendicular to the drum axial direction X. FIG. 3 shows a surface of the head 10 that faces the photosensitive drum 110. It is a top view which shows the above structure. A sectional view taken along line II-II in FIG. 3 corresponds to FIG. As shown in FIGS. 1 to 3, the head 10 includes a substantially rectangular parallelepiped support 31, a light emitting device 33 and two rollers disposed in a portion of the support 31 facing the photosensitive drum 110. 35. The support 31 is formed of plastic, for example, and is arranged so that the longitudinal direction thereof faces the drum axis direction X.

  The light emitting device 33 is a means for forming a latent image on the photosensitive drum 110 by light irradiation. As shown in FIG. 3, the substrate 331 having a substantially rectangular shape whose longitudinal direction is the drum axis direction X, and the substrate 331. And a plurality of light emitting elements 332 arranged in an array on the surface. Each light emitting element 332 is an element in which a light emitting layer made of an organic EL material is interposed between an anode and a cathode. As shown in FIG. 3, these light emitting elements 332 are arranged in two rows and zigzag along the drum axis direction X, and selectively emit light according to an image to be printed on a recording material such as paper. Light emitted from each light emitting element 332 reaches the surface of the photosensitive drum 110. By this exposure, a latent image corresponding to a desired image is formed on the surface of the photosensitive drum 110. Note that the arrangement pattern of the light emitting elements 332 is not limited to the example of FIG. 3, and may be a single row, three or more rows, or another appropriate pattern.

  On the other hand, the roller 35 is a cylindrical and black member having a diameter of about 1 mm to 2 mm, and is formed of a resin material such as plastic. The overall length of the roller 35 is equal to or longer than the width of the photosensitive drum 110 (dimension in the drum axial direction X).

  On the surface of the support 31 that faces the photosensitive drum 110, a groove 311 is formed in each part that sandwiches the light emitting device 33. Each groove 311 is a recessed portion having a width slightly larger than the diameter (about 1 mm to 2 mm) of each roller 35, and extends in the drum axial direction X along the arrangement of the light emitting devices 33. Each roller 35 is accommodated in the groove 311. Therefore, the rotation axis of the roller 35 is oriented in a direction perpendicular to the direction in which the photosensitive drum 110 travels (that is, a direction parallel to the drum axis direction X). Further, as described above, since the entire length of the roller 35 is equal to or longer than the width of the photosensitive drum 110, each roller 35 faces the surface of the entire photosensitive drum 110 in the width direction.

  4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIGS. 3 and 4, shaft portions 351 extending along the center line of each roller 35 are formed on both end surfaces of each roller 35. On the other hand, a lid 313 facing the bottom surface 312 of the groove 311 is formed at the end in the longitudinal direction of each groove 311 of the support 31 with the shaft 351 interposed therebetween. The lid 313 prevents the roller 35 from falling from the support 31.

  As shown in FIGS. 2 and 3, the diameter of the roller 35 is larger than the depth of the groove 311. Therefore, the portion of the outer peripheral surface of the roller 35 accommodated in the groove 311 that faces the photosensitive drum 110 protrudes from the support 31 toward the photosensitive drum 110. On the other hand, the portion of the roller 35 opposite to the photosensitive drum 110 faces the bottom surface 312 of the groove 311 with a slight gap.

  As shown in FIG. 1 and FIG. 2, a plurality of elastic bodies 41 are arranged in a portion of the support 31 that is opposite to the photosensitive drum 110. Each elastic body 41 is a means for urging the support 31 toward the photosensitive drum 110 and is interposed between the housing 50 and the support 31 of the image printing apparatus. In the present embodiment, as shown in FIG. 1, a total of six elastic bodies 41 are arranged in the vicinity of each corner on the upper surface of the support 31 and the center in the longitudinal direction.

  As each elastic body 41, for example, a coil spring having one end fixed to the support 31 and the other end fixed to the housing 50 is employed. However, the specific form of the elastic body 41 is arbitrary. That is, a member that elastically urges the support 31 toward the photosensitive drum 110 is sufficient. For example, a spring of another form such as a leaf spring or the support 31 and the housing 50 is inserted. Various other members such as rubber are employed as the elastic body 41.

  As shown by the arrow F 1 in FIGS. 1 and 2, the support 31 is urged toward the photosensitive drum 110 by these elastic bodies 41. By this urging, the roller 35 is pressed against the surface of the photosensitive drum 110, and a frictional force is generated between the roller 35 and the photosensitive drum 110. Therefore, when the photosensitive drum 110 rotates in the direction of the arrow A1 in FIG. 2, the roller 35 rotates in the direction of the arrow A2 so as to follow this rotation.

  As described above, in this embodiment, the elastic body 41 presses the support 31 and the roller 35 comes into contact with the surface of the photosensitive drum 110. Therefore, the dimensions and attachment of the head 10 and the photosensitive drum 110 are the same. Even when there is an error in position, or when a surface runout occurs on the surface of the photosensitive drum 110 due to insufficient roundness of the cross section of the photosensitive drum 110 or an error in the drum axial direction X, Each light emitting element 332 follows the surface of the photosensitive drum 110. Therefore, the distance between the light emitting element 332 and the photosensitive drum 110 can be maintained at a desired size.

  Further, since the roller 35 of the head 10 contacts the surface of the photosensitive drum 110 and rotates with the rotation of the photosensitive drum 110, the contact between the head 10 and the photosensitive drum 110 will be described below. Various problems caused by the problem can be solved.

  For example, in the configuration disclosed in Patent Document 1, there is a problem that the head 10 vibrates due to contact with the photosensitive drum 110. However, in this embodiment, the frictional force from the photosensitive drum 110 is applied to the head 10. Since it hardly acts, vibration of the head 10 due to rotation of the photosensitive drum 110 is prevented. Therefore, the distance between each light emitting element 332 and the photosensitive drum 110 can be accurately maintained at a desired dimension. Further, compared to the conventional configuration in which the photosensitive drum 110 rotates while the head 10 is in contact with the photosensitive drum 110, wear of portions of the head 10 and the photosensitive drum 110 that are in contact with each other is suppressed. Therefore, the change with time of the interval between the light emitting element 332 and the photosensitive drum 110 can also be suppressed. Further, even if a foreign object is caught between the roller 35 and the photosensitive drum 110, the foreign object is quickly removed by the rotation of the roller 35. Therefore, the surface of the photosensitive drum 110 is removed by such a foreign object. Damage is prevented.

  In the present embodiment, a plurality of elastic bodies 41 are dispersedly arranged on the upper surface of the support 31. According to this configuration, the support body 31 can be pressed evenly as compared with the configuration in which the elastic body 41 is unevenly distributed in a specific region on the upper surface of the support body 31. Can be made uniform.

  By the way, as shown in FIG. 1, when the elastic body 41 is arranged at the center in the longitudinal direction of the support body 31, the support body 31 bends due to the pressing force from the elastic body 41 and the weight of the support body 31. There is a case. In this case, for example, the bottom surface 312 of the groove 311 contacts the roller 35 in the portion B of FIG. 4, and the rotation of the roller 35 may be hindered by the friction. Therefore, it is desirable that the bottom surface 312 of the groove 311 formed on the support 31 or the outer peripheral surface of the roller 35 has a smaller friction coefficient. According to this configuration, even if the bottom surface 312 of the groove 311 and the roller 35 come into contact with each other, the frictional force acting on the contacted portion is sufficiently small, so that the roller 35 can be smoothly rotated. Alternatively, the support 31 may be formed of a material having sufficiently high rigidity. According to this configuration, since the bending of the support 31 is suppressed, the contact of the bottom surface 312 with the roller 35 can be avoided. Further, the rotation of the roller 35 is also prevented by the configuration in which the elastic body 41 is not disposed in the center portion in the longitudinal direction of the support body 31 (for example, the elastic body 41 is disposed only in the vicinity of the four corners on the upper surface of the support body 31). The bending of the support body 31 which becomes a cause can be suppressed.

  In the present embodiment, each roller 35 disposed at a position sandwiching each light emitting element 332 has a light shielding property. According to this configuration, the light emitted from the light emitting element 332 and diffused in a wide range is blocked by the roller 35. Therefore, the light from the light emitting element 332 can be selectively irradiated only to a region (region R shown in FIG. 2) sandwiched between the rollers 35 on the surface of the photosensitive drum 110, and as a result, high definition. In addition, clear image printing is realized. In particular, in this embodiment, since the roller 35 faces the surface of the photosensitive drum 110 over the entire width direction of the photosensitive drum 110, the light from each light emitting element 332 is applied to the entire width direction of the photosensitive drum 110. Diffusion can be prevented.

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described.
In the first embodiment, the configuration in which the elastic body 41 that presses the support 31 toward the photosensitive drum 110 is disposed on the upper surface of the support 31 is exemplified. On the other hand, in the present embodiment, the support 31 is urged toward the photosensitive drum 110 by the elastic body disposed on the side of the support 31. In addition, the same code | symbol is attached | subjected about the element similar to 1st Embodiment among this embodiment, and the description is abbreviate | omitted suitably.

  FIG. 5 is a perspective view showing configurations of the head 10 and the photosensitive drum 110 of the image printing apparatus according to the present embodiment. FIG. 6 is a cross-sectional view showing a configuration when the element shown in FIG. 5 is broken along a plane perpendicular to the drum axial direction X, and corresponds to FIG. 2 in the first embodiment. As shown in FIGS. 5 and 6, the image printing apparatus according to the present embodiment includes a frame member 53 formed in a substantially rectangular frame shape surrounding the periphery of the head 10. The inner peripheral surface of the frame member 53 faces the side surface of the support 31.

  A plurality of elastic bodies 42 are interposed between the inner peripheral surface of the frame member 53 and the side surface of the support 31. One end of each elastic body 42 is fixed to the inner peripheral surface of the frame member 53, and the other end is fixed to the side surface of the support 31. More specifically, as shown in FIG. 5, one end of three elastic bodies 42 arranged at equal intervals is fixed to each side surface corresponding to the long side of the substantially rectangular support 31. The other ends of these elastic bodies 42 are fixed to the inner peripheral surface of the frame member 53 facing this side surface. Further, one end of one elastic body 42 is fixed to each side surface corresponding to the short side of the support 31, and the other end of the elastic body 42 is connected to the inner peripheral surface of the frame member 53 facing the side surface. Is fixed.

  A plurality of elastic bodies 43 are disposed on the surface of the frame member 53 opposite to the photosensitive drum 110. Each elastic body 43 is a means for urging the frame member 53 toward the photosensitive drum 110, and is interposed between the housing 50 and the frame member 53 of the image printing apparatus. In the present embodiment, a total of six elastic bodies 43 are arranged in the vicinity of each corner of the frame member 53 and in the vicinity of the center in the longitudinal direction. The elastic body 42 and the elastic body 43 are the same elements as the elastic body 41 of the first embodiment, and are, for example, a coil spring or a leaf spring.

  In the configuration described above, the elastic body 43 extends when the elastic body 43 presses the frame member 53 toward the photosensitive drum 110, and the support 31 is moved toward the photosensitive drum 110 by the elastic force generated in the elastic body 42. Be energized. Therefore, also in this embodiment, since each roller 35 contacts the surface of the photosensitive drum 110, the same effect as in the first embodiment is produced. Note that the frame member 53 is not limited to the shape shown in FIG.

  In the above description, the structure in which the frame member 53 is pressed against the photosensitive drum 110 by the elastic body 43 has been exemplified. However, as shown in FIG. It may be configured to be biased toward the photosensitive drum 110 side. In other words, in this configuration, the end P1 of each elastic body 42 fixed to the frame member 53 is positioned closer to the photosensitive drum 110 than the end P2 of the elastic body 42 fixed to the support 31. Thus, the frame member 53 is fixed to the housing 50. Also with this configuration, the support 31 is urged toward the photosensitive drum 110 by the elastic force of the elastic body 42, so that the same operations and effects as in the first and second embodiments are achieved. In addition, according to this configuration, it is not necessary to arrange the elastic body 43 in the portion of the support 31 or the frame member 53 that is opposite to the photosensitive drum 110, so that a space to be secured above the head 10 is provided. Can be reduced.

<C: Modification>
Various modifications are added to the above embodiment. An example of a specific modification is as follows. In addition, you may combine each aspect shown below suitably.

(1) Modification 1
In each embodiment, the configuration in which the head 10 is disposed so as to face the outer peripheral surface of the cylindrical photosensitive drum 110 is illustrated. However, as illustrated in FIG. 8, the light emitting device 33 and the roller 35 include the photosensitive drum 110. A configuration in which the head 10 is disposed inside the photosensitive drum 110 so as to face the inner peripheral surface of the photosensitive drum 110 is also employed. The photosensitive drum 110 in this configuration is configured by laminating a photosensitive layer on the outer peripheral surface of a light-transmitting cylinder. According to this configuration, the space required for the arrangement of the head 10 can be reduced as compared with the configuration of each embodiment.

  In the above description, the cylindrical photosensitive drum 110 is exemplified as the image carrier. However, as shown in FIG. 9, an endless belt 56 wound around a plurality of rollers 551 and proceeding in the direction of the arrow A1 is used. You may employ | adopt as an image carrier. 9 illustrates a configuration in which the head 10 is opposed to the outer peripheral surface of the endless belt 56, but a configuration in which the head 10 is opposed to the inner peripheral surface of the endless belt 56 is also employed, as in the configuration of FIG. Is done. 8 and 9 exemplify the configuration in which the head 10 is biased by the configuration according to the first embodiment, the same modification may be added to the configuration of the second embodiment. As described above, in the present invention, the roller is instructed to the support so that the rotation axis faces the direction perpendicular to the direction of travel of the image carrier (the direction of the generatrix line). It does not matter whether the shape of the image carrier is sufficient.

(2) Modification 2
As described in the first embodiment, when the bottom surface 312 of the groove 311 in the support 31 comes into contact with the roller 35, the rotation is prevented. As a measure for solving this, in the first embodiment, the configuration in which the friction coefficient of the bottom surface 312 of the groove 311 is reduced is exemplified, but the roller 35 can be smoothly rotated also by the configuration in FIG. In the configuration shown in the figure, a recess 315 is further formed in the bottom surface 312 of the groove 311 in the support 31, and the auxiliary roller 37 is disposed in the recess 315. The auxiliary roller 37 is a columnar member whose rotating shaft faces in a direction parallel to the roller 35, and is pivotally supported by the support 31 in a posture in which the side surface is in contact with the side surface of the roller 35. When the roller 35 rotates with the rotation of the photosensitive drum 110, the auxiliary roller 37 rotates following the rotation of the roller 35. According to this configuration, since the bottom surface 312 of the groove 311 does not contact the roller 35, the roller 35 can be smoothly rotated.

(3) Modification 3
In each embodiment, the configuration in which the light emitting device 33 directly faces the photoconductive drum 110 (that is, the configuration in which no member is interposed between the light emitting device 33 and the photoconductive drum 110) is exemplified. An optical element may be interposed between the photosensitive member 33 and the photosensitive drum 110. For example, a light guide (for example, an optical fiber) that guides light emitted from each light emitting element 332 to the surface of the photosensitive drum 110 and a lens (for example, a converging lens array) that collects light emitted from each light emitting element 332 emit light. It may be interposed between the device 33 and the photosensitive drum 110.

  In addition, as shown in FIG. 11, a microlens 74 for condensing outgoing light from the light emitting element 33 may be disposed between the light emitting device 33 and the photosensitive drum 110. These microlenses 74 are arranged in an array so that each of the microlenses 74 faces the light emitting element 332. In the configuration illustrated in FIG. 11, the first substrate 71 and the second substrate 72 that are bonded to face each other are disposed in the gap between the light emitting device 33 and the photosensitive drum 110. On the surface of the first substrate 71 facing the second substrate 72, a plurality of concave portions 711 having a curved surface shape are formed at positions corresponding to the light emitting elements 332, and the second substrate 72 faces the first substrate 71. A plurality of curved concave portions 721 are formed on the surface. A space surrounded by the recess 711 of the first substrate 71 and the recess 721 of the second substrate 72 is filled with a resin material having a refractive index different from that of the first substrate 71 and the second substrate 72. And the microlens 74 which is a biconvex lens is formed with this resin material. As indicated by a two-dot chain line in FIG. 11, these microlenses 74 focus the light emitted from the corresponding light emitting elements 332 to form an image on the surface of the photosensitive drum 110. Note that the shape of the microlens 74 and the manner in which the microlens 74 is arranged are not limited to those illustrated in FIG. For example, a microlens that is convex toward the photosensitive drum 110 may be formed on the substrate 331 of the light emitting device 33.

  As described above, in the configuration in which the emitted light from the light emitting element 332 is collected by the microlens 74, even if the distance between the light emitting element 33 and the photosensitive drum 110 is slightly changed, The change in the diameter of the spot area of the surface where the emitted light from the light emitting element 33 reaches becomes remarkable. According to the present embodiment, the distance between the light emitting device 33 and the photosensitive drum 110 can be maintained substantially constant with high accuracy by the action of the roller 35, and thus the configuration in which the light use efficiency is improved by the microlens 74. In this case, a desired latent image can be accurately formed on the surface of the photosensitive drum 110. That is, the effect of the present invention that the distance between the light emitting device 33 and the photosensitive drum 110 can be maintained is that a microlens 74 or the like is provided in the gap between the light emitting device 33 and the photosensitive drum 110 as shown in FIG. This can be said to be particularly effective in a configuration in which optical elements are arranged. However, according to the configuration in which the light emitting device 33 and the photosensitive drum 110 are close to each other without any member as in each embodiment, the utilization efficiency of light emitted from each light emitting element 332 is improved and the manufacturing cost is reduced. There is an advantage that reduction can be achieved. In addition, since the luminance of the light emitting element 332 necessary for reaching a sufficient amount of light to the surface of the photosensitive drum 110 can be reduced, the power consumption in the light emitting device 33 is reduced and the life of the light emitting element 332 is increased. It is done.

(4) Modification 4
In each embodiment, the configuration in which the two rollers 35 are arranged so as to sandwich the light emitting device 33 is exemplified, but the number of the rollers 35 and the positions at which the rollers 35 are arranged are arbitrarily changed. In the first embodiment, the configuration in which the light-shielding roller 35 suppresses the diffusion of the emitted light from the light-emitting element 332 is illustrated, but the diffusion of the emitted light from the light-emitting element 332 is not particularly problematic ( For example, a configuration in which a member that blocks diffused light is provided separately from the roller 35, or a configuration in which light diffusion is suppressed by an optical element such as a lens), a configuration in which the roller 35 is formed of a light-transmitting material, A configuration in which the entire length of the roller 35 is shorter than the width of the photosensitive drum 110 is also employed. Also, as shown in FIG. 12, a plurality of rollers 35 may be arranged in a straight line at intervals.

(5) Modification 5
In each embodiment, the light emitting element 332 including the light emitting layer made of the organic EL material is illustrated, but a head or an LED (Light Emitting Diode) in which the light emitting elements including the light emitting layer made of the inorganic EL material are arranged is used as the light emitting element. Each aspect described above is also applied to the arranged heads. That is, the light-emitting element in the present invention may be an element that emits light by applying electric energy.

<D: Image printing apparatus>
Next, the overall configuration of the image printing apparatus according to the present invention will be described with reference to FIG. This image printing apparatus is a tandem type full-color image printing apparatus using a belt intermediate transfer body system.

  In this image printing apparatus, four organic EL array exposure heads 10K, 10C, 10M, and 10Y having the same configuration are replaced with four photosensitive drums (image carriers) 110K, 110C, 110M, and 110Y having the same configuration. The exposure positions are respectively arranged. The organic EL array exposure heads 10K, 10C, 10M, and 10Y are the heads 10 according to any one of the embodiments exemplified above.

  As shown in FIG. 13, this image printing apparatus is provided with a driving roller 121 and a driven roller 122. An endless intermediate transfer belt 120 is wound around these rollers 121 and 122, and an arrow indicates. As shown, the periphery of the rollers 121 and 122 is rotated. Although not shown, tension applying means such as a tension roller that applies tension to the intermediate transfer belt 120 may be provided.

  Around the intermediate transfer belt 120, four photosensitive drums 110K, 110C, 110M, and 110Y each having a photosensitive layer on the outer peripheral surface are arranged at a predetermined interval. The subscripts K, C, M, and Y mean that they are used to form black, cyan, magenta, and yellow visible images, respectively. The same applies to other members. The photosensitive drums 110K, 110C, 110M, and 110Y are rotationally driven in synchronization with the driving of the intermediate transfer belt 120.

  Around each photosensitive drum 110 (K, C, M, Y), a corona charger 111 (K, C, M, Y), an organic EL array exposure head 10 (K, C, M, Y), and , Developing devices 114 (K, C, M, Y) are arranged. The corona charger 111 (K, C, M, Y) uniformly charges the outer peripheral surface of the corresponding photosensitive drum 110 (K, C, M, Y). The organic EL array exposure head 10 (K, C, M, Y) writes an electrostatic latent image on the charged outer peripheral surface of the photosensitive drum. In each organic EL array exposure head 10 (K, C, M, Y), the plurality of light emitting elements 332 in the light emitting device 33 are along the bus (main scanning direction) of the photosensitive drum 110 (K, C, M, Y). It is installed so that it may be arranged. The electrostatic latent image is written by irradiating the photosensitive drum with light by a plurality of light emitting elements 332. The developing device 114 (K, C, M, Y) forms a visible image, that is, a visible image on the photosensitive drum by attaching toner as a developer to the electrostatic latent image.

  The black, cyan, magenta, and yellow developed images formed by the four-color single-color image forming station are sequentially transferred onto the intermediate transfer belt 120 to be superimposed on the intermediate transfer belt 120. As a result, a full-color image is obtained. Four primary transfer corotrons (transfer devices) 112 (K, C, M, Y) are arranged inside the intermediate transfer belt 120. The primary transfer corotron 112 (K, C, M, Y) is disposed in the vicinity of the photosensitive drum 110 (K, C, M, Y), and the photosensitive drum 110 (K, C, M, Y). The electrostatic image is electrostatically attracted from the toner image to transfer the visible image to the intermediate transfer belt 120 passing between the photosensitive drum and the primary transfer corotron.

  A sheet 102 as an object on which an image is to be finally formed is fed one by one from the sheet feeding cassette 101 by the pickup roller 103, and between the intermediate transfer belt 120 and the secondary transfer roller 126 in contact with the driving roller 121. Sent to the nip. The full-color visible image on the intermediate transfer belt 120 is secondarily transferred to one side of the sheet 102 by the secondary transfer roller 126 and fixed on the sheet 102 through the fixing roller pair 127 as a fixing unit. . Thereafter, the sheet 102 is discharged onto a paper discharge cassette formed in the upper part of the apparatus by a paper discharge roller pair 128.

  Next, another embodiment of the image printing apparatus according to the present invention will be described with reference to FIG. This image printing apparatus is a rotary development type full-color image printing apparatus using a belt intermediate transfer body system. As shown in FIG. 14, a corona charger 168, a rotary developing unit 161, an organic EL array exposure head 167, and an intermediate transfer belt 169 are provided around the photosensitive drum 165.

  The corona charger 168 uniformly charges the outer peripheral surface of the photosensitive drum 165. The organic EL array exposure head 167 writes an electrostatic latent image on the charged outer peripheral surface of the photosensitive drum 165. The organic EL array exposure head 167 is the head 10 according to any of the above-described embodiments, and is installed such that a plurality of light emitting elements 332 are arranged along the bus (main scanning direction) of the photosensitive drum 165. The The electrostatic latent image is written by irradiating the photosensitive drum 165 with light from the light emitting elements 332.

  The developing unit 161 is a drum in which four developing units 163Y, 163C, 163M, and 163K are arranged at an angular interval of 90 °, and can rotate counterclockwise about the shaft 161a. The developing units 163Y, 163C, 163M, and 163K supply yellow, cyan, magenta, and black toners to the photosensitive drum 165, respectively, and attach the toner as a developer to the electrostatic latent image, thereby the photosensitive drum 165. A visible image, that is, a visible image is formed.

  The endless intermediate transfer belt 169 is wound around a driving roller 170a, a driven roller 170b, a primary transfer roller 166, and a tension roller, and is rotated around these rollers in a direction indicated by an arrow. The primary transfer roller 166 transfers the visible image to the intermediate transfer belt 169 that passes between the photosensitive drum and the primary transfer roller 166 by electrostatically attracting the visible image from the photosensitive drum 165.

  Specifically, in the first rotation of the photosensitive drum 165, an electrostatic latent image for a yellow (Y) image is written by the exposure head 167, and a developed image of the same color is formed by the developing unit 163Y. The image is transferred to the transfer belt 169. Further, in the next rotation, an electrostatic latent image for a cyan (C) image is written by the exposure head 167, and a developed image of the same color is formed by the developing device 163C. The intermediate transfer is performed so as to overlap the yellow developed image. Transferred to the belt 169. Then, during the four rotations of the photosensitive drum 165, yellow, cyan, magenta, and black visible images are sequentially superimposed on the intermediate transfer belt 169. As a result, a full-color visible image is formed on the transfer belt 169. It is formed. When images are finally formed on both sides of a sheet as an object on which an image is to be formed, the same color images of the front and back surfaces are transferred to the intermediate transfer belt 169, and then the front and back surfaces are transferred to the intermediate transfer belt 169. A full-color visible image is obtained on the intermediate transfer belt 169 by transferring the visible image of the next color.

  The image printing apparatus is provided with a sheet conveyance path 174 through which a sheet is passed. The sheets are picked up one by one from the paper feed cassette 178 by the pick-up roller 179, advanced through the sheet transport path 174 by the transport roller, and between the intermediate transfer belt 169 and the secondary transfer roller 171 in contact with the drive roller 170a. Pass through the nip. The secondary transfer roller 171 transfers the developed image to one side of the sheet by electrostatically attracting a full-color developed image from the intermediate transfer belt 169 collectively. The secondary transfer roller 171 can be moved closer to and away from the intermediate transfer belt 169 by a clutch (not shown). The secondary transfer roller 171 is brought into contact with the intermediate transfer belt 169 when a full-color visible image is transferred onto the sheet, and is separated from the secondary transfer roller 171 while the visible image is superimposed on the intermediate transfer belt 169.

  The sheet on which the image has been transferred as described above is conveyed to the fixing device 172 and is passed between the heating roller 172a and the pressure roller 172b of the fixing device 172, whereby the visible image on the sheet is fixed. The sheet after the fixing process is drawn into the discharge roller pair 176 and proceeds in the direction of arrow F. In the case of double-sided printing, after most of the sheet passes through the paper discharge roller pair 176, the paper discharge roller pair 176 is rotated in the reverse direction and introduced into the double-sided printing conveyance path 175 as indicated by an arrow G. The Then, the visible image is transferred to the other surface of the sheet by the secondary transfer roller 171, the fixing process is performed again by the fixing device 172, and then the sheet is discharged by the discharge roller pair 176.

  The image printing apparatus illustrated in FIGS. 13 and 14 uses the light emitting element 332 including a light emitting layer made of an organic EL material as writing means (exposure means), so that it is more than using a laser scanning optical system. Therefore, it is possible to reduce the size of the apparatus. Note that the light-emitting device of the present invention can also be employed in electrophotographic image printing apparatuses other than those exemplified above. For example, the light emitting device according to the present invention can be applied to an image printing apparatus that directly transfers a visible image from a photosensitive drum to a sheet without using an intermediate transfer belt, and an image printing apparatus that forms a monochrome image. Is possible.

1 is a perspective view illustrating a partial configuration of an image printing apparatus according to a first embodiment of the present invention. It is sectional drawing which shows the structure of a head and its periphery. It is a top view which shows the structure of the surface which opposes a photoreceptor drum among heads. It is sectional drawing seen from the IV-IV line in FIG. It is a perspective view which shows the structure of a part of image printing apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the structure of a head and its periphery. It is sectional drawing which shows the structure of the head which concerns on the modification of 2nd Embodiment, and its periphery. FIG. 10 is a cross-sectional view illustrating a configuration of an image printing apparatus according to Modification Example 1. FIG. 10 is a cross-sectional view illustrating a configuration of another image printing apparatus according to Modification 1. FIG. 10 is a cross-sectional view illustrating a configuration of a roller of an image printing apparatus according to a second modification and its surroundings. 10 is a cross-sectional view illustrating a configuration of an image printing apparatus according to Modification 3. FIG. FIG. 10 is a plan view illustrating a configuration of a surface facing a photosensitive drum in a head according to a modification example 4; 1 is a longitudinal sectional view illustrating the overall configuration of an image printing apparatus according to the present invention. It is a longitudinal cross-sectional view which shows the other structure of the image printing apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Head, 110 ... Photosensitive drum, 31 ... Support, 311 ... Groove, 312 ... Bottom, 33 ... Light emitting device, 331 ... Substrate, 332 ... Light emitting element, 35 ... Roller, 351: Shaft, 41, 42, 43 ... Elastic body, 50 ... Housing, 53 ... Frame member.

Claims (8)

An image carrier traveling in one direction;
A support opposite to the image carrier;
A plurality of light emitting elements provided in a portion of the support facing the image carrier and forming a latent image on the image carrier by light emission;
A roller disposed on a portion of the support opposite to the image carrier, with a rotation axis directed in a direction substantially perpendicular to a direction of travel of the image carrier;
An image printing apparatus comprising: an urging unit that urges the support toward the image carrier so that the roller contacts the image carrier. 2. The image printing according to claim 1, wherein the urging unit includes a plurality of elastic bodies that are provided in a portion of the support opposite to the image carrier and press the support. 3. apparatus. 2. The urging means includes a frame member having a portion facing a side surface of the support body, and an elastic body interposed between the side surface of the support body and the frame member. The image printing apparatus described. The image printing apparatus according to claim 3, wherein the urging unit includes an elastic body that presses the frame member toward the image carrier. A groove extending in a direction substantially perpendicular to the traveling direction of the image carrier is formed in a portion of the support that faces the image carrier.
2. The roller according to claim 1, wherein the roller is accommodated in the groove such that a part of an outer peripheral surface protrudes from the surface facing the image carrier of the support to the image carrier side. Image printing device. The image printing apparatus according to claim 5, further comprising an auxiliary roller disposed on a bottom surface of the groove and having a side surface contacting the side surface of the roller. A plurality of the rollers disposed at positions facing each other across the plurality of light emitting elements among the support;
The image printing apparatus according to claim 1, wherein each roller is opposed to the surface of the image carrier over the entire width of the image carrier. 8. The image printing according to claim 1, further comprising a lens that is interposed between the image carrier and the light emitting element and collects light emitted from the light emitting element. apparatus.

Images