JP2012111134A - Exposure head and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that can thin an exposure head while securing a wiring space in a configuration where light emitting elements and a driving circuit are provided in the same substrate.SOLUTION: An exposure head includes: a first substrate that seals an organic EL by using a light transmissive sealing material and has a first terminal arranged at one side of the organic EL and a second terminal arranged at the other side; a driving part that is arranged on the first substrate between either the first terminal or the second terminal and the organic EL; a second substrate that has a third terminal connected to the first terminal and a fourth terminal connected to the second terminal, supports the first substrate and through which light passing through the sealing member via the emission of the organic EL; and wiring that is arranged on the second substrate between either the third terminal or the fourth terminal and the organic EL viewed from a normal line of the second substrate.

Description

  The present invention relates to an exposure head that performs exposure using light emitted from a light emitting element in response to driving of a drive unit.

  Patent Document 1 describes an exposure head in which a plurality of light emitting elements arranged in the longitudinal direction is provided on a substrate and an exposure operation is performed by light emitted from each light emitting element. Further, in this exposure head, a drive unit composed of a transistor or the like is provided on the same substrate as the light emitting element, and each light emitting element emits light in response to driving from the drive unit.

JP 2009-154528 A

  However, in the configuration in which the driving circuit is provided as described above, it is necessary to separately provide wiring for supplying power to the driving circuit and wiring for supplying a control signal for controlling driving of the light emitting element to the driving circuit. When the space for arranging these wirings is secured on the same substrate as the light emitting element and the driving unit, there is a problem that the width of the exposure head becomes wide.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object to provide a technique capable of slimming an exposure head while securing a wiring space in a configuration in which a light emitting element and a drive circuit are provided on the same substrate. To do.

  In order to achieve the above object, the exposure head according to the present invention seals the organic EL arranged in the first direction with a light-transmitting sealing member and is orthogonal or substantially orthogonal to the first direction. A first substrate having a first terminal disposed on one side of the organic EL in the second direction and a second terminal disposed on the other side of the organic EL in the second direction; A drive unit that is arranged on the first substrate between the terminal or the second terminal and the organic EL and drives the organic EL to emit light; and a third terminal and a third terminal connected to the first terminal The fourth terminal is arranged on the second direction side of the first terminal and is connected to the second terminal to support the first substrate, and the light emitted from the organic EL and passing through the sealing member is transmitted. Between the second terminal and the third terminal or the fourth terminal when viewed from the normal direction of the second substrate and the organic EL It is characterized by and a wiring disposed on the second substrate.

  In order to achieve the above object, the image forming apparatus according to the present invention seals the organic EL arranged in the first direction with a light-transmitting sealing member and is orthogonal or substantially orthogonal to the first direction. A first substrate having a first terminal disposed on one side of the organic EL in the second direction and a second terminal disposed on the other side of the organic EL in the second direction; A driving unit disposed on the first substrate between the terminal or the second terminal and the organic EL to drive the organic EL to emit light; a third terminal connected to the first terminal; and a third terminal of the third terminal A second terminal arranged on the direction side of 2 and connected to the second terminal to support the first substrate, and the organic EL emits light and the light transmitted through the sealing member is transmitted through the second terminal. And the third terminal or the fourth terminal between the organic EL and the third terminal when viewed from the normal direction of the second substrate and the second substrate. An exposure head having a wiring which is arranged in the substrate, is characterized by and a latent image carrier on which a latent image is formed is exposed by the exposure head.

  In the invention thus configured (exposure head, image forming apparatus), two substrates, a first substrate on which an organic EL (light emitting element) is arranged in the first direction, and a light transmissive second substrate. Is provided. The first substrate is provided with first and second terminals so that the organic EL is sandwiched in a second direction orthogonal or substantially orthogonal to the first direction. Third and fourth terminals are arranged in the direction. Then, the first and second terminals and the third and fourth terminals are connected to each other so that the first substrate is supported by the second substrate. In other words, The exposure head has a configuration in which these first and second substrates are stacked.

  According to the present invention, the driving unit that drives the light emitting element to emit light is arranged on the first substrate between the first or second terminal and the organic EL, and the wiring is the same as that of the second substrate. The third substrate or the fourth terminal and the organic EL are arranged on the second substrate when viewed from the line direction. In the present invention, by configuring such first and second substrates to overlap each other, it is possible to substantially overlap the driving unit and the wiring. As a result, the width of the first and second substrates can be suppressed and the exposure head can be made slim.

  Various examples of the form and application of the wiring arranged on the second substrate can be considered. Therefore, the wiring may be configured to be electrically connected to the third terminal or the fourth terminal. Further, the wiring may be a control signal line through which a signal for controlling the light emission of the organic EL by the driving unit flows, or the wiring may be a power supply line for supplying power to the driving unit.

  In addition, various examples of connection methods of the terminals can be considered. For example, the first terminal and the third terminal are connected by a bump, and the second terminal and the fourth terminal are connected by a bump. It may be configured.

  By the way, as described above, in the configuration in which the second substrate is stacked on the first substrate on which the light emitting element is arranged, the light emitted from the light emitting element passes through the second substrate after passing through the sealing member. To be exposed. At this time, if there is a gap such as an air layer between the sealing member and the second substrate, a large amount of light is reflected on the surface of the second substrate, which may reduce the amount of light used for exposure. Therefore, the insulating transparent resin may be filled between the sealing member and the second substrate. This makes it easy to suppress the reflection of light on the surface of the second substrate and ensure the amount of light used for exposure.

The figure which shows an example of the line head which can apply this invention. The figure which shows arrangement | positioning of the light emitting element in the line head of FIG. The partial top view of the chip | tip seen from the optical axis direction. The figure which shows partially the cross section of the width direction of the chip | tip seen from the longitudinal direction LGD. The width direction fragmentary sectional view which shows the silicon substrate of the state mounted in the head substrate. The top view which shows an example of the arrangement | positioning form of each wiring in a head substrate back surface. 1 is a diagram illustrating an example of an image forming apparatus to which a line head can be applied. The block diagram which shows the electric constitution of the apparatus of FIG. The top view which shows the modification of the arrangement | positioning form of each wiring in a head substrate back surface. The top view which shows the modification of the arrangement | positioning form of each wiring in a head substrate back surface. The top view which shows the modification of the arrangement | positioning form of each wiring in a head substrate back surface. The top view which shows the modification of the arrangement | positioning form of each wiring in a head substrate back surface.

  FIG. 1 is a diagram showing an example of a line head to which the present invention can be applied. In particular, the cross-section of the line head 29 (A-A cross section shown in FIG. 2) is partially shown from the longitudinal direction LGD. ing. As shown by a broken line in FIG. 1, the line head 29 forms an image of light from the light emitting element formed on the chip CP by the imaging optical systems LS1 and LS2, and forms an exposed surface ES such as the surface of the photosensitive drum. The spot SP is formed. FIG. 2 is a diagram showing the arrangement of the light emitting elements in the line head of FIG. 1, particularly when the configuration of the head substrate 293 that supports the chip CP on which the light emitting element E is formed is viewed from the optical axis direction Doa. Partially shown. In addition, in FIG. 1 and the figure demonstrated later, the hatching of the dot is suitably given with respect to the cross section of the member comprised with optically transparent materials, such as glass. In FIG. 2, members (LS1, LS2, D1) other than the members arranged on the head substrate 293 are indicated by one-dot / two-dot chain lines, but this is the light-emitting element E and each member (LS1, LS2,. This is to make it easier to understand the correspondence with D1).

  The line head 29 has an overall configuration that is long in the longitudinal direction LGD and short in the width direction LTD. Therefore, in FIG. 1 and the drawings described later, the longitudinal direction LGD and the width direction LTD of the line head 29 are shown as necessary. In addition, the optical axis direction Doa of the imaging optical systems LS1 and LS2 is also shown as appropriate. Here, the optical axis direction Doa is parallel to the optical axis OA of the imaging optical systems LS1 and LS2, and is a direction in which the light emitting elements formed on the chip CP emit light. Note that these directions LGD, LTD, and Doa are orthogonal or substantially orthogonal to each other. Further, in the following, the arrow side in the optical axis direction Doa is expressed as “front” or “upper” and the opposite side to the arrow in the optical axis direction Doa is expressed as “back”, “lower”, or “bottom” as necessary. To do.

  As will be described later, when the line head 29 is applied to the image forming apparatus, the line head 29 is exposed to an exposed surface ES (photosensitive drum) that moves in the sub-scanning direction SD that is orthogonal or substantially orthogonal to the main scanning direction MD. The main scanning direction MD of the exposed surface ES is parallel or substantially parallel to the longitudinal direction LGD of the line head 29, and the sub-scanning direction SD of the exposed surface ES is a line. It is parallel or substantially parallel to the width direction LTD of the head 29. Therefore, as necessary, the main scanning direction MD and the sub-scanning direction SD are also illustrated together with the longitudinal direction LGD and the width direction LTD.

  The line head 29 includes a head substrate 293 that supports the chip CP, and lens arrays LA1 and LA2 on which lenses LS1 and LS2 are formed. In the chip CP, a plurality of (16) light emitting elements E arranged in a zigzag manner in two rows in the longitudinal direction LGD at the light emitting element pitch Pe are grouped to form a light emitting element group EG, and a plurality (5) of light emitting elements are formed. The element groups EG are linearly arranged at a predetermined pitch (Dg × 2) in the longitudinal direction LGD. A plurality of chips CP are arranged in a zigzag pattern in two rows in the longitudinal direction LGD, and are mounted face-down on the back surface 293-t of the glass head substrate 293. As a result, a plurality of light emitting element groups EG facing the back surface 293-t of the head substrate 293 are arranged in a staggered manner in two rows at a pitch Dg in the longitudinal direction LGD, and each light emitting element E of the light emitting element group EG The light passes through the head substrate 293 and is emitted from the head substrate surface 293-h.

  On the surface 293-h of the head substrate 293, spacers AS1 are arranged on both sides in the width direction LTD, and a lens array LA1 is installed on these spacers AS1 in the width direction LTD. On the back surface of the lens array LA1, a plurality of lenses LS1 are arranged in a zigzag pattern in the longitudinal direction LGD corresponding to the arrangement of the light emitting element groups EG. Accordingly, one lens LS1 is opposed to one light emitting element group EG. Incidentally, the lens LS1 has a convex shape with respect to the light emitting element group EG and is made of resin.

  Further, spacers AS2 are arranged on both sides of the width direction LTD on the surface of the lens array LA1, and the lens array LA2 is installed in the width direction LTD on these spacers AS2. On the back surface of the lens array LA2, a plurality of lenses LS2 are arranged in a zigzag pattern in the longitudinal direction LGD corresponding to the arrangement of the light emitting element groups EG. As a result, one lens LS2 is opposed to one light emitting element group EG. Incidentally, the lens LS2 has a convex shape with respect to the light emitting element group EG and is made of resin.

  Further, the line head 29 includes a light shielding member 295 between the head substrate 293 and the lens array LA1. The light shielding member 295 has five light shielding plates FP1 to FP5 arranged in the optical axis direction Doa. More specifically, the light shielding member 295 is provided with two spacers arranged on the head substrate surface 293-h with an interval in the width direction LTD, and a light shielding plate FP1 is installed on these spacers. ing. Further, the light shielding member 295 is provided with two spacers arranged on the surface of the light shielding flat plate FP1 with an interval in the width direction LTD. The light shielding flat plate FP2 is installed on these spacers, and other light shielding is similarly performed. The flat plates FP3 to FP5 are also stacked via spacers.

  In the light shielding plate FP1, a light guide hole D1 having a circular shape centered on the optical axis OA of the lenses LS1 and LS2 and penetrating in the optical axis direction Doa is formed for each light emitting element group EG. Thus, on the light shielding flat plate FP1, a plurality of light guide holes D1 are arranged in a zigzag pattern in the longitudinal direction LGD corresponding to the arrangement of the light emitting element groups EG. Similarly, for each of the other light shielding flat plates FP2 to FP5, light guide holes D2 to D5 are arranged in a zigzag pattern in the longitudinal direction LGD corresponding to the arrangement of the light emitting element groups EG. The diameter of the light guide hole D1 closest to the head substrate 293 is smaller than the diameters of the other light guide holes D2 to D5.

  Thus, the light guide holes D1 to D5 and the lenses LS1 and LS2 arranged in a line in the optical axis direction Doa face each light emitting element group EG. Accordingly, among the light emitted from each light emitting element E of the light emitting element group EG, the light that has passed through the light guide holes D1 to D5 is incident on the lenses LS1 and LS2 and is imaged. The imaging optical systems LS1 and LS2 have inversion / reduction imaging magnification (that is, the imaging magnification is a negative value and an absolute value is less than 1).

  The above is the schematic configuration of the line head 29. Next, a detailed configuration of the chip CP included in the line head 29 will be described with reference to FIGS. 3 and 4. Here, FIG. 3 is a partial plan view of the chip as seen from the optical axis direction. FIG. 4 is a diagram partially showing a cross-section in the width direction of the chip viewed from the longitudinal direction LGD. The chip CP includes a silicon substrate SS having a rectangular shape that is long in the longitudinal direction LGD and short in the width direction LTD. On the silicon substrate SS, an organic EL as the light emitting element E, a drive circuit DC for driving the light emitting element E, and the like are integrated and formed by a semiconductor process.

  More specifically, in the silicon substrate SS, five sets of light emitting element groups EG are formed side by side in the longitudinal direction LGD. Each light emitting element E of these light emitting element groups EG is a so-called top emission type organic EL, and emits light with an equal or substantially equal emission spectrum. The silicon substrate SS is formed with a light-transmitting sealing thin film SL that seals the light-emitting element E in order to block the light-emitting element E, which is an organic EL, from moisture or oxygen (moisture or the like). At this time, in order to prevent moisture from entering between the sealing thin film SL and the silicon substrate SS, it is preferable to form the sealing thin film SL around the light emitting element E with a certain margin. Specifically, a margin of about 0.5 [mm] to 2 [mm] is appropriate. Note that, as in the present embodiment, by arranging a plurality of light emitting element groups EG in a discrete manner, the distance from the end of the chip CP to the light emitting element group EG can be secured, and the light emitting element group EG to the chip CP can be secured. The sealing thin film SL can be provided with a sufficient margin between the ends. However, the terminal Ta is not covered with the sealing thin film SL, and the electrical connection of the terminal Ta is ensured.

The sealing thin film SL is preferably a strong film of an inorganic material having gas barrier properties. Specifically, silicon nitride (Si ₃ N ₄ , refractive index: 2.00), silicon dioxide (SiO ₂ , refractive index: 1.54), aluminum oxide (alumina, AL ₂ O ₃ , refractive index: 1. 77) can be used. Here, the value of the refractive index is a value for the wavelength 650 [nm]. Although these materials sufficiently block moisture and the like even in a thin film, defects are likely to occur if they are too thin, and cracks are likely to occur if they are too thick, so thicknesses of several tens [nm] to several hundreds [nm] Is preferred. The sealing thin film SL is formed by plasma coating, sputtering, or the like. However, since the organic EL is weak against heat, it is preferable to use a film forming process with little temperature rise.

  In the silicon substrate SS, the drive circuit DC disposed so as to overlap the light emitting element E is formed in the lower layer of each light emitting element E (that is, the light emitting element E and the drive circuit DC are stacked). In other words, the drive circuits DC arranged in a zigzag pattern in the longitudinal direction LGD at the light emitting element pitch Pe are formed in the lower layer of the light emitting element group EG. Thus, the strip-like drive circuit DC that is long in the width direction LTD is extended from each light emitting element E to the outside of the width direction LTD. Thus, by using the top emission type organic EL as the light emitting element E, the light emitting element E can be formed directly above the drive circuit DC. For this reason, it is not necessary to provide a space between the light emitting elements E in order to secure the arrangement area of the drive circuit DC, and the light emitting elements E can be arranged at high density. The driving circuit DC is composed of a transistor that drives the light emitting element E and a capacitor that holds a voltage applied to an input terminal of the transistor.

  Further, on both sides in the width direction LTD of the light emitting element group EG, a plurality of terminals Ta are linearly arranged in the longitudinal direction LGD at a pitch of about 100 [μm]. At this time, the plurality of terminals Ta are provided so that each drive circuit DC is located between the terminal Ta provided at the end in the width direction LTD and the light emitting element group EG. In this way, in the width direction LTD, the terminal Ta is arranged so as to sandwich the light emitting element group EG and the drive circuit DC provided on both sides thereof. As described above, in order to secure the arrangement space of the drive circuit DC, the light emitting element group EG and the terminal Ta are arranged with an interval of 0.5 [mm] or more in the width direction LTD. Each terminal Ta is connected to the drive circuit DC via a connection line integrated on the silicon substrate SS by a semiconductor process.

  The silicon substrate SS configured as described above is flip-chip mounted on the back surface 293-t of the light-transmissive head substrate 293 (glass substrate) (FIG. 5). FIG. 5 is a partial cross-sectional view in the width direction showing the silicon substrate mounted on the head substrate. As shown in the figure, the silicon substrate SS is mounted face-down on the back surface 293-t of the head substrate 293 with the surface on which the light emitting element E is formed facing the back surface 293-t of the head substrate 293.

  More specifically, a plurality of terminals Tb are formed on the back surface 293-t of the head substrate 293 in one-to-one correspondence with the terminals Ta. Then, a bump made of metal such as gold provided on the terminal Ta of the silicon substrate SS is pressure-bonded to the terminal Tb of the head substrate back surface 293-t. Thus, the terminal Ta of the silicon substrate SS and the terminal Tb of the head substrate back surface 293-t are electrically connected, and the silicon substrate SS is supported by the head substrate 293. Incidentally, it is preferable that the surface of the terminal Tb on the back surface 293-t of the head substrate is plated with gold.

Thus, by bonding the silicon substrate SS to the head substrate 293, the deformation of the silicon substrate SS is suppressed by the head substrate 293, and the sealing of the light emitting element E can be suppressed from being broken by the deformation of the silicon substrate SS. In particular, when the head substrate 293 has a function of suppressing deformation of the silicon substrate SS, it is not necessary to separately provide a member such as a cover glass for the function, and the entire line head 29 can be thinned. In the configuration in which the silicon substrate SS is bonded to the head substrate 293, the light emitting element E of the silicon substrate SS can be positioned with reference to the head substrate 293. However, in order to take advantage of this advantage, It is preferable to ensure the flatness of the head substrate 293 by setting the thickness to 0.3 [mm] to 1.5 [mm]. Further, since the head substrate 293 is made of glass having a small linear expansion coefficient of 3 to 8 × 10 ⁻⁶ , the linear expansion coefficient is the same as that of the lens arrays LA1 and LA2, and the relative position change due to the temperature change is suppressed. Stable exposure is possible regardless of the above.

  Further, a light transmissive transparent resin TP (filling member) is filled between the silicon substrate SS and the head substrate 293. Thus, air is excluded from between the silicon substrate SS and the head substrate 293. At this time, the transparent resin TP is provided so as to cover the sealing thin film SL on the surface of the silicon substrate SS. Further, the transparent resin TP is filled between the silicon substrate SS and the head substrate 293, and is also filled into a gap Δcp between two silicon substrates SS adjacent in the width direction LTD. Further, the transparent resin TP protruding from the end of the silicon substrate SS is provided so as to go from the side of the silicon substrate SS to the back surface. And the refractive index of this transparent resin TP is larger than the refractive index of air, and is below the refractive index of sealing thin film SL.

As such a transparent resin TP, a general ultraviolet (UV) curable resin can be used, and an anaerobic adhesive, a two-component mixed adhesive, or a thermosetting adhesive can be used. When an adhesive other than the ultraviolet curable resin is used, there is an advantage that there is no possibility that the organic EL is deteriorated by ultraviolet rays irradiated to cure the transparent resin TP. Moreover, as a material of transparent resin TP, an epoxy resin (refractive index 1.55-1.6), an acrylic resin (refractive index 1.49), and a silicon resin (1.4-1.45) are suitable. In particular, when silicon nitride (Si ₃ N ₄ ) having a high refractive index is used, a material having a high refractive index (refractive index of 1.6 to 1.65) among the epoxy resins is preferably used for the transparent resin TP.

  As a method for filling such a resin, a method similar to the underfill generally used in flip chip mounting can be used. That is, after the bump BP of the silicon substrate SS and the electrode of the head substrate 293 are pressure-bonded, the transparent resin TP is poured from the gap between the silicon substrate SS and the head substrate 293 using surface tension. At this time, by keeping the viscosity of the transparent resin TP low, the transparent resin TP can be spread quickly on the surface of the silicon substrate SS. Further, by setting the viscosity of the transparent resin TP to 1000 [mPa · s] or less, preferably 100 [mPa · s] or less, it is possible to fill the transparent resin TP while suppressing entrainment of bubbles. Note that the gap filled with the transparent resin TP is determined by the height of the bump BP or the height at which the bump BP is crushed. A typical gold stud bump has a height of around 50 [μm], and when it is crimped and pressed, it collapses to about half of the height, so that a gap of about 20 [μm] is secured. Therefore, a resin having a low viscosity can sufficiently penetrate. In this embodiment, since the head substrate 293 is transparent, the transparent resin TP can be cured by irradiating light through the head substrate 293 after infiltrating the transparent resin TP.

  At this time, the transparent resin TP to be filled only needs to have transparency according to the wavelength to be used. For example, a photoconductor used in electrophotography has a high sensitivity to light of red to near-infrared wavelength (600 to 800 [nm]). Therefore, the transparent resin TP used in this embodiment has transparency to this wavelength. There is no problem even if it is slightly colored yellow when visually observed. Further, the internal transmittance of the resin shows a value per 10 [mm] of the transmission thickness, but in this embodiment, since the thickness of the transparent resin TP is thin, the value indicated as the internal transmittance is low. But in practice there are few problems. In general, since the absorption rate is proportional to an exponential function of thickness, for example, even if the internal transmittance at 10 [mm] thickness is 10 [%], the transmittance is about 99 [%] at a thickness of 50 [μm]. become. Thus, there is little problem if the transmission loss is 1%. Therefore, even if it looks yellow like a normal epoxy resin, there is no problem because the transmittance at a necessary wavelength is surely 10% or more.

  Since it is configured as described above, the light emitted from the light emitting element E is transmitted through the sealing thin film SL, the transparent resin TP, and the head substrate 293 in this order, and then subjected to exposure. In this embodiment, since the transparent resin TP having a refractive index larger than that of air is filled between the silicon substrate SS and the head substrate 293, the amount of light reflected by the back surface 293-t of the head substrate 293 is suppressed. It is possible to improve the light use efficiency. Moreover, the problem that the light reflected by the back surface 293-t of the head substrate 293 becomes stray light and causes ghost is also suppressed. Further, by filling the transparent resin TP between the silicon substrate SS and the head substrate 293, foreign matter can be prevented from entering directly above the light emitting element E of the silicon substrate SS, and the light emitted from the light emitting element E is foreign matter. Occurrence of the problem that the light utilization efficiency decreases due to scattering by the light is suppressed.

  By the way, when operating the drive circuit DC so that the light emitting element emits light appropriately, power is supplied to the drive circuit DC, and further, a control signal for controlling light emission of the light emitting element E by the drive circuit DC is supplied to the drive circuit DC. It is necessary to supply. Therefore, in this embodiment, these wirings are provided on the back surface 293-t of the head substrate 293. Next, the arrangement of these wirings will be described.

  FIG. 6 is a plan view showing an example of an arrangement form of each wiring on the back surface of the head substrate. The figure shows a plan view from the normal direction of the head substrate back surface 293-t (which coincides with the optical axis direction Doa), and understands the correspondence between each wiring on the head substrate back surface 293-t and the chip CP. For ease of illustration, the chip CP and its constituent members (light emitting elements E) are shown together with broken lines. Note that since the terminal Ta of the chip CP overlaps the terminal Tb of the back surface 293-t of the head substrate, the notation of the terminal Tb is used instead of the notation of the terminal Ta.

  Further, in the terminal row composed of the terminals Tb linearly arranged in the longitudinal direction LGD, a space between the first terminal row and the light emitting element group EG is denoted by reference symbol A1, and the second terminal row and the light emission. A space between the element group EG is denoted by reference symbol A2, a space between the third terminal row and the light emitting element group EG is denoted by reference symbol A3, and the fourth terminal row and the light emitting element group EG A space A is designated by A4. Such notation is also used as appropriate in the following drawings.

  As described above, in the chip CP, the drive circuit DC is formed between the terminal Ta and the light emitting element group EG. Accordingly, the spaces A1 to A4 on the back surface 293-t of the head substrate are located directly above or substantially above the drive circuit DC. In the example of the wiring mode shown below, the line head 29 is slimmed down by effectively utilizing the spaces A1 to A4 provided on the drive circuit DC. Details are as follows.

  On the back surface 293-t of the head substrate, bus lines Lb1 and Lb2 through which control signals flow, power supply lines VEL1 and VLE2, a ground line GND, and the like are provided. Further, in correspondence with the fact that a plurality of chips CP are arranged in a zigzag manner with two rows in the longitudinal direction LGD, in the example shown in FIG. 6, a row consisting of the chips CP constituting the first row and a second row are constituted. The bus lines and the power supply wiring systems are divided by the rows of the chips CP.

  Specifically, for each chip CP in the first row, a bus line Lb1 that mainly passes through the space A2 (between the terminal Ta and the light emitting element group EG in the chip CP in the first row) is provided. The terminals Ta of these chips CP are connected to each other by a bus line Lb1. Further, for each chip CP in the first row, a power supply line VEL1 mainly passing through the space A1 (between the terminal Ta and the light emitting element group EG in the chip CP in the first row) is provided. A terminal Ta of each chip CP is connected to a common power supply line VEL1.

  On the other hand, for each chip CP in the second row, a bus line Lb2 that mainly passes through the space A3 (between the terminal Ta and the light emitting element group EG in the chip CP in the second row) is provided. The terminals Ta of the chip CP are connected to each other by a bus line Lb1. Further, for each chip CP in the second row, a power supply line VEL2 mainly passing through the space A4 (between the terminal Ta and the light emitting element group EG in the chip CP in the second row) is provided. A terminal Ta of each chip CP is connected to a common power supply line VEL2.

  The ground line GND is shared by the chips CP in the first and second rows. Specifically, the ground line GND is disposed so as to pass between the chip CP in the first row and the chip CP in the second row, and the terminal Ta of the chip CP in the first row and the second row is connected to this ground. It is connected to the line GND.

  As described above, in this embodiment, two substrates, the chip CP (first substrate) on which the light emitting element E is formed in the longitudinal direction LGD and the light-transmissive head substrate 293 (second substrate), are provided. ing. In the chip CP, a terminal Ta is arranged so as to sandwich the light emitting element group EG in the width direction LTD, and a terminal Tb is also arranged in the width direction LTD on the head substrate 293. The terminal Ta and the terminal Tb are connected to each other so that the chip CP is supported by the head substrate 293. In other words, the line head 29 overlaps the chip CP and the head substrate 293. It has a configuration as described above.

  In this embodiment, the driving circuit DC that drives the light emitting element E to emit light is formed in the chip CP between the terminal Ta and the light emitting element group EG. In contrast, the wirings Lb1, Lb2, VEL1, and VEL2 are arranged on the head substrate 293 between the terminal Tb and the light emitting element group EG in the plan view of FIG. In this embodiment, the chip CP and the head substrate 293 are configured to overlap each other, so that the drive circuit DC and the wirings Lb1, Lb2, VEL1, and VEL2 can be substantially overlapped. ing. As a result, the width of the chip CP / head substrate 293 can be suppressed, and the line head 29 can be slimmed.

  Further, in this embodiment, the space A1 to A4 between the terminal Tb and the light emitting element group EG and the space between the terminals Tb adjacent to the width direction LTD (space where the ground line GND is disposed) are ensured. Thus, a large number of wirings can be routed without crossing. Accordingly, it is not necessary to provide two or more wiring layers or jumper wirings on the head substrate 293 (glass substrate), and wiring formation on the head substrate 293 is facilitated.

  Furthermore, in this embodiment, spaces A1 to A4 between the terminal Tb and the light emitting element group EG and spaces between the terminals Tb adjacent to the width direction LTD (space where the ground line GND is arranged) are secured. By doing so, it becomes possible to pass a large number of wirings of one or more, and it becomes easy to pass a large number of wirings connecting the chips CP (silicon substrate) or between the chip CP and an external circuit. Further, for the same reason, a thick wiring pattern can be passed, and the electric resistances of the power supply lines VEL1, VEL2 and the ground line GND can be kept low. In particular, in the line head 29 using the organic EL as the light emitting element E, it is necessary to pass a larger amount of current through the light emitting element E than in other devices such as a display. Therefore, the above embodiment is suitable for the line head 29. It is a thing.

  Further, since the number of input / output terminals is small with respect to the size of the chip CP, a wide interval between the terminals Tb can be secured. Therefore, it is possible to easily form a wiring that passes between the terminals Tb adjacent in the longitudinal direction LGD.

  Incidentally, as described above, in this embodiment, the plurality of chips CP are arranged in a zigzag pattern in two rows in the longitudinal direction LGD, and the layout of terminals and wirings can be the same in each row. As a result, since the layout of terminals and wiring can be shared by each row, it is possible to reduce costs by sharing components.

  Further, in the above-described embodiment, the wiring patterns Ls1 and Ls2 that connect each chip CP and an external circuit can be arranged by using a region outside the width direction LTD of the chip CP. Note that the wiring patterns Ls1 and Ls2 can be used to transmit signals that need to be accessed to individual chips, such as chip select signals.

Configuration of Image Forming Apparatus Next, an example of an image forming apparatus to which the line head 29 described in the above embodiment can be applied will be described. FIG. 7 is a diagram illustrating an example of an image forming apparatus to which the above-described line head can be applied. FIG. 8 is a block diagram showing an electrical configuration of the apparatus of FIG. The image forming apparatus 1 includes four image forming stations 2Y (for yellow), 2M (for magenta), 2C (for cyan), and 2K (for black) that form images of different colors. The image forming apparatus 1 includes a color mode in which four color toners of yellow (Y), magenta (M), cyan (C), and black (K) are overlapped to form a color image, and black (K). A monochrome mode in which a monochrome image is formed using only toner can be selectively executed.

  In this image forming apparatus, when an image forming command is given from an external device such as a host computer to a main controller MC having a CPU, a memory, etc., the main controller MC provides a control signal to the engine controller EC and also supports the image forming command. The video data VD to be transmitted is supplied to the head controller HC. At this time, every time the main controller MC receives the horizontal request signal HREQ from the head controller HC, the main controller MC supplies video data VD for one line to the head controller HC in the main scanning direction MD. The head controller HC also sets the line heads 29 of the image forming stations 2Y, 2M, 2C, and 2K for each color based on the video data VD from the main controller MC, the vertical synchronization signal Vsync from the engine controller EC, and the parameter values. Control. Accordingly, the engine unit ENG executes a predetermined image forming operation, and forms an image corresponding to the image forming command on a sheet-like recording medium RM such as copy paper, transfer paper, paper, and an OHP transparent sheet.

  Each of the image forming stations 2Y, 2M, 2C, and 2K has the same structure and function except for the toner color. Therefore, in FIG. 7, in order to make the drawing easier to see, reference numerals are given only to the components constituting the image forming station 2 </ b> C, and description of reference numerals to be attached to the other image forming stations 2 </ b> Y, 2 </ b> M, and 2 </ b> K is omitted. In the following description, the structure and operation of the image forming station 2C will be described with reference to the reference numerals attached to FIG. 7, but the structure and operation of the other image forming stations 2Y, 2M, and 2K also differ in toner color. It is the same except that.

  The image forming station 2C is provided with a photosensitive drum 21 on which a cyan toner image is formed. The photosensitive drum 21 is arranged so that the rotation axis thereof is parallel or substantially parallel to the main scanning direction MD (direction perpendicular to the paper surface of FIG. 7), and a predetermined speed in the direction of arrow D21 in FIG. Is driven to rotate. As a result, the surface of the photosensitive drum 21 moves in the sub-scanning direction SD that is orthogonal or substantially orthogonal to the main scanning direction MD.

  Around the photosensitive drum 21, a charger 22 that is a corona charger that charges the surface of the photosensitive drum 21 to a predetermined potential, and an electrostatic latent image is formed by exposing the surface of the photosensitive drum 21 according to an image signal. A line head 29 for forming the electrostatic latent image, a developing device 24 for visualizing the electrostatic latent image as a toner image, a first squeeze unit 25, a second squeeze unit 26, and the surface of the photosensitive drum 21 after transfer. The cleaning units for cleaning are arranged along the rotation direction D21 (clockwise in FIG. 7) of the photosensitive drum 21 in this order.

  In this embodiment, the charger 22 includes two corona chargers 221 and 222, and the corona charger 221 is disposed upstream of the corona charger 222 in the rotation direction D 21 of the photosensitive drum 21. In addition, the two corona chargers 221 and 222 are configured to be charged in two stages. Each of the corona chargers 221 and 222 has the same configuration and does not contact the surface of the photosensitive drum 21 and is a scorotron charger.

  The line head 29 forms an electrostatic latent image on the surface of the photosensitive drum 21 charged by the corona chargers 221 and 222 based on the video data VD. That is, when the head controller HC transmits the video data VD to the line head 29, the drive circuit DC emits each light emitting element E in response to the supply of the drive signal corresponding to the video data VD. As a result, the surface of the photosensitive drum 21 is exposed to form an electrostatic latent image corresponding to the image signal. The specific configuration of the line head 29 is as already described.

  Toner is applied from the developing device 24 to the electrostatic latent image formed in this manner, and the electrostatic latent image is developed with the toner. The developing device 24 of the image forming apparatus 1 has a developing roller 241. The developing roller 241 is a cylindrical member, and is provided with an elastic layer such as polyurethane rubber, silicon rubber, NBR, or PFA tube on the outer periphery of an inner core made of metal such as iron. The developing roller 241 is connected to a developing motor and is rotated counterclockwise on the paper surface of FIG. 7 to rotate with respect to the photosensitive drum 21. Further, the developing roller 241 is electrically connected to a developing bias generator (constant voltage power source) (not shown) so that the developing bias is applied at an appropriate timing.

  An anilox roller is provided to supply the liquid developer to the developing roller 241, and the liquid developer is supplied from the developer storage unit to the developing roller 241 via the anilox roller. As described above, the anilox roller has a function of supplying the liquid developer to the developing roller 241. This anilox roller is a roller in which a concave pattern is formed by spiral grooves or the like engraved finely and uniformly on the surface so as to easily carry the liquid developer. Similar to the developing roller 241, a metal cored bar wrapped with a rubber layer such as urethane or NBR, or a PFA tube is used. The anilox roller is connected to a developing motor and rotates.

  The liquid developer stored in the developer storage section is volatile at room temperature at a low concentration (1-2 wt%) and low viscosity using Isopar (trademark: Exon) as a liquid carrier, which is generally used conventionally. Not a volatile liquid developer having a solid particle having a mean particle size of 1 μm, in which a colorant such as a pigment is dispersed in a non-volatile resin having a high concentration and high viscosity at room temperature, an organic solvent, silicon oil, mineral oil or A liquid developer having a high viscosity (about 30 to 10,000 mPa · s) added to a liquid solvent such as edible oil together with a dispersant and having a toner solid content concentration of about 20% is used.

  As described above, the developing roller 241 supplied with the liquid developer rotates simultaneously with the anilox roller and rotates so as to move in the same direction as the surface of the photosensitive drum 21 and is carried on the surface of the developing roller 241. The liquid developer thus conveyed is conveyed to the development position. In order to form a toner image, the rotation direction of the developing roller 241 needs to be rotated so that the surface thereof moves in the same direction as the surface of the photosensitive drum 21, but is opposite to the anilox roller. It may be configured to move in either the direction or the same direction.

  In the developing device 24, a toner compression corona generator 242 is disposed opposite to the developing roller 241 immediately before the developing position in the rotation direction of the developing roller 241. The toner compression corona generator 242 is an electric field applying means for increasing the charging bias on the surface of the developing roller 241 and is electrically connected to a toner charge generator (not shown) configured with a constant current power source. When a toner charge bias is applied to the toner compression corona generator 242, an electric field is applied to the liquid developer toner conveyed by the developing roller 241 at a position close to the toner compression corona generator 242. Then, charging and compression are performed. For the toner charging and compression, a compaction roller that is charged by contact may be used instead of corona discharge by applying electrolysis.

  Further, the developing device 24 configured as described above can reciprocate between a developing position for developing the latent image on the photosensitive drum 21 and a retracted position away from the photosensitive drum 21. Therefore, when the developing device 24 is moved to the retracted position and positioned, supply of new liquid developer to the photosensitive drum 21 is stopped in the cyan image forming station 2C.

  A first squeeze portion 25 is disposed on the downstream side of the developing position in the rotation direction D <b> 21 of the photosensitive drum 21, and a second squeeze portion 26 is disposed on the downstream side of the first squeeze portion 25. These squeeze portions 25 and 26 are provided with squeeze rollers 251 and 261, respectively. Then, the squeeze roller 251 rotates in response to the rotational driving force from the main motor while contacting the surface of the photosensitive drum 21 at the first squeeze position to remove excess developer in the toner image. Further, in the rotation direction D21 of the photosensitive drum 21, the squeeze roller 261 rotates in response to the rotational driving force from the main motor while contacting the surface of the photosensitive drum 21 at the second squeeze position downstream of the first squeeze position. Then, excess liquid carrier and fog toner in the toner image are removed. In this embodiment, a squeeze bias generator (constant voltage power supply) (not shown) is electrically connected to the squeeze rollers 251 and 261 in order to increase the squeeze efficiency, and the squeeze bias is applied at an appropriate timing. It is configured to be. In this embodiment, the two squeeze portions 25 and 26 are provided. However, the number and arrangement of the squeeze portions are not limited to this, and for example, one squeeze portion may be disposed.

  The toner image that has passed through these squeeze positions is primarily transferred to the intermediate transfer member 31 of the transfer unit 3. The intermediate transfer member 31 is an endless belt as an image carrier that can temporarily carry a toner image on its surface, more specifically, on its outer peripheral surface. The intermediate transfer member 31 includes a plurality of rollers 32, 33, 34, 35, and 36. It is being handed over. Among these, the roller 32 is connected to a main motor, and functions as a belt driving roller that drives the intermediate transfer member 31 in the direction of the arrow D31 in FIG. In the present embodiment, an elastic layer is provided on the surface of the intermediate transfer body 31 in order to improve the adhesion with the recording paper RM and improve the transferability of the toner image onto the recording paper RM. A toner image is supported.

  Here, of the rollers 32 to 36 over which the intermediate transfer body 31 is stretched, only the belt driving roller 32 is driven by the main motor, and the other rollers 33 to 36 are driven without a driving source. It is a roller. Further, the belt driving roller 32 winds the intermediate transfer member 31 on the downstream side of the primary transfer position TR1 and the upstream side of the secondary transfer position TR2 described later in the belt moving direction D31.

  The transfer unit 3 includes a primary transfer backup roller 37, and the primary transfer backup roller 37 is disposed to face the photosensitive drum 21 with the intermediate transfer member 31 interposed therebetween. At the primary transfer position TR1 where the photosensitive drum 21 and the intermediate transfer member 31 are in contact, the outer peripheral surface of the photosensitive drum 21 is in contact with the intermediate transfer member 31 to form the primary transfer nip portion NP1c. Then, the toner image on the photosensitive drum 21 is transferred to the outer peripheral surface of the intermediate transfer member 31 (the lower surface at the primary transfer position TR1). Thus, the cyan toner image formed by the image forming station 2C is transferred to the intermediate transfer member 31. Similarly, the toner images are transferred at the other image forming stations 2Y, 2M, and 2K, so that the toner images of the respective colors are sequentially superimposed on the intermediate transfer member 31 to form a full-color toner image. On the other hand, when a monochrome toner image is formed, the toner image is transferred to the intermediate transfer member 31 only in the image forming station 2K corresponding to the black color.

  The toner image transferred to the intermediate transfer member 31 in this way is conveyed to the secondary transfer position TR2 via the winding position around the belt driving roller 32. At the secondary transfer position TR2, the secondary transfer roller 42 of the secondary transfer unit 4 is disposed opposite to the roller 34 around which the intermediate transfer body 31 is wound, with the intermediate transfer body 31 interposed therebetween. The surface 31 and the surface of the transfer roller 42 are in contact with each other to form the secondary transfer nip portion NP2. That is, the roller 34 functions as a secondary transfer backup roller. The rotation shaft of the backup roller 34 is supported elastically by a pressing portion 345 which is an elastic member such as a spring and can be moved toward and away from the intermediate transfer member 31.

  At the secondary transfer position TR2, the single-color or multi-color toner images formed on the intermediate transfer member 31 are transferred from the pair of gate rollers 51 to the recording medium RM conveyed along the conveyance path PT. Further, the recording medium RM on which the toner image is secondarily transferred is sent from the secondary transfer roller 42 to the fixing unit 7 provided on the transport path PT. In the fixing unit 7, heat or pressure is applied to the toner image transferred to the recording medium RM to fix the toner image on the recording medium RM. In this way, a desired image can be formed on the recording medium RM.

Others As described above, in the above embodiment, the line head 29 corresponds to the “exposure head” of the present invention, and the photosensitive drum 21 corresponds to the “latent image carrier” of the present invention. The longitudinal direction LGD corresponds to the “first direction” of the present invention, the width direction LTD corresponds to the “second direction” of the present invention, and the chip CP corresponds to the “first substrate” of the present invention. The head substrate 293 corresponds to the “second substrate” of the present invention, the terminal Ta corresponds to the “first terminal” and the “second terminal” of the present invention, and the terminal Tb corresponds to the “third substrate” of the present invention. The sealing thin film SL corresponds to the “sealing member” of the present invention, and the bus lines Lb1 and Lb2 or the power supply lines VEL1 and VEL2 correspond to the “wiring” of the present invention. To do.

  The present invention is not limited to the above-described embodiment, and various modifications can be made to the above-described one without departing from the spirit of the present invention. Therefore, various modifications can be made to the wiring arrangement on the head substrate back surface 293-t as shown in FIGS. Here, FIG. 9 to FIG. 12 are plan views showing modifications of the arrangement form of each wiring on the back surface of the head substrate. The notation in these figures is the same as the notation in FIG.

  In the example shown in FIG. 6, each of the bus lines and the power supply wiring system includes a row made up of the chips CP constituting the first row and a row made up of the chips CP constituting the second row in the 2-row staggered arrangement. Was divided. On the other hand, in the modification shown in FIG. 9, only one common bus line is provided in each row. Specifically, the bus line Lb is provided so as to pass between the chip CP of the first row and the chip CP of the second row, and each chip CP (terminal Ta thereof) is paralleled by the bus line Lb. It is connected. As for the power supply, two systems of power supplies VEL1 and VEL2 are provided in the same manner as in FIG. 6, and are mainly arranged in the spaces A1 and A4, respectively. In the example shown in FIG. 9, the ground line GND is also provided with two systems (GND1, GND2) including a row composed of the chips CP constituting the first row and a row composed of the chips CP constituting the second row. Are mainly arranged in the spaces A2 and A3, respectively. In the example shown in FIG. 9, a plurality of wirings are formed between the terminals Tb adjacent to the longitudinal direction LGD, taking advantage of the feature of the present embodiment that a wide interval between the terminals Tb can be secured.

  As shown in FIG. 10, chips CP adjacent to each other in the longitudinal direction LGD can be cascade-connected with a cascade connection line, and a control signal can be transferred between the chips CP via the cascade connection line. Specifically, the cascade connection lines are divided into a row made up of the chips CP constituting the first row and a row made up of the chips CP constituting the second row in the 2-row staggered arrangement. In other words, each chip CP in the first row is provided with a cascade connection line Lc1 that mainly passes through the space A2 (between the terminal Ta and the light emitting element group EG in the chip CP in the first row). The terminals Ta of the chips CP to be cascaded are connected by the cascade connection line Lc1. On the other hand, each chip CP in the second row is provided with a cascade connection line Lc2 that mainly passes through the space A3 (between the terminal Ta and the light emitting element group EG in the chip CP in the second row). The terminals Ta of the chips CP are connected to each other by a cascade connection line Lc2. Note that the wiring form of the power supply line and the ground line in FIG. 10 is the same as that in FIG.

  In addition to the cascade connection line, a bus line may be further provided as shown in FIG. That is, in the modification shown in FIG. 11, the bus line Lb1 is provided for each chip CP in the first row, and the bus line Lb2 is provided for each chip CP in the second row. More specifically, for each chip CP in the first row, the bus line Lb1 mainly passing through the spaces A1 and A2 (both between the terminal Ta and the light emitting element group EG in the chip CP in the first row). The bus line Lb1 is connected to the terminal Ta of each chip CP. On the other hand, for each chip CP in the second row, a bus line Lb2 that mainly passes through the spaces A3 and A4 (both between the terminal Ta and the light emitting element group EG in the chip CP in the second row) is provided. The bus line Lb2 is connected to the terminal Ta of each chip CP.

  10 and 11, the cascade connection line system is divided between the first row chip CP and the second row chip CP. However, as shown in FIG. 12, all chips are connected in one system cascade connection. You may connect by the line Lc. Specifically, in FIG. 12, chips CP arranged in two rows and staggered in the longitudinal direction LGD are sequentially connected by one cascade connection line Lc. At this time, in arranging the cascade connection line Lc, the space A3 (between the terminal Ta and the light emitting element group EG) is effectively utilized. In the example shown in FIG. 12, a plurality of wirings are formed between the terminals Tb adjacent to the longitudinal direction LGD, taking advantage of the feature of the present embodiment that a wide interval between the terminals Tb can be secured.

  As described above, also in the modified examples shown in FIGS. 9 to 12, the spaces A1 to A4 on the drive circuit DC are utilized for passing the wiring. Therefore, it is possible to reduce the width of the chip CP / head substrate 293 and make the line head 29 slim.

  Also, in the modified examples shown in FIGS. 9 to 12, a plurality of chips CP are arranged in a zigzag pattern in two rows in the longitudinal direction LGD, and the layout of terminals and wirings can be the same in each row. It has become. As a result, since the layout of terminals and wiring can be shared by each row, it is possible to reduce costs by sharing components.

  Also, in the modified examples shown in FIGS. 9 to 12, a large number of spaces A1 to A4 between the terminal Tb and the light emitting element group EG and a space between the terminals Tb adjacent in the width direction LTD are secured. It is possible to route the wires without crossing. Accordingly, it is not necessary to provide two or more wiring layers or jumper wirings on the head substrate 293 (glass substrate), and wiring formation on the head substrate 293 is facilitated, and between the chip CP (silicon substrates) or between It becomes easy to pass a large number of wires connecting the chip CP and external circuits. Further, for the same reason, a thick wiring pattern can be passed, and the electric resistances of the power supply lines VEL1, VEL2 and the ground line GND can be kept low. Further, since the number of input / output terminals is small with respect to the size of the chip CP, a wide interval between the terminals Tb can be secured. Therefore, it is possible to easily form a wiring that passes between the terminals Tb adjacent in the longitudinal direction LGD. Further, in the above-described embodiment, the wiring patterns Ls1 and Ls2 that connect each chip CP and an external circuit can be arranged by using a region outside the width direction LTD of the chip CP.

  Note that further modifications can be made to the bus line, the power supply line, or the ground line. Specifically, these lines may be arranged by being divided into plurals in the longitudinal direction LGD of the line head 29. When configured in this manner, a voltage drop can be prevented for the power supply line and the ground line, and a signal delay can be prevented for the bus line. In particular, since the metal wiring on the glass has a higher resistance than the copper foil of a general printed board, such a divided structure is useful.

  Further, the arrangement mode of the light emitting element group EG and the lenses LS1, LS2 is not limited to the above, and other arrangement modes such as a three-row zigzag pattern can be adopted. Further, the number and arrangement of the light emitting elements E constituting the light emitting element group EG can be changed as appropriate.

  DESCRIPTION OF SYMBOLS 21 ... Photosensitive drum, 29 ... Line head, 293 ... Head substrate, 295 ... Light shielding member, SS ... Silicon substrate, CP ... Chip, SL ... Sealing thin film, E ... Light emitting element (organic EL), Ta ... Terminal, Tb ... terminal, Lb1 ... bus line, Lb2 ... bus line, Lc1 ... cascade connection line, Lc2 ... cascade connection line, VEL1 ... power supply line, VEL2 ... power supply line, LGD ... longitudinal direction, LTD ... width direction, Doa ... optical axis direction (Normal direction of head substrate)

Claims (7)

The organic EL arranged in the first direction is sealed with a light-transmitting sealing member, and is arranged on one side of the organic EL in a second direction orthogonal or substantially orthogonal to the first direction. A first substrate having a first terminal and a second terminal disposed on the other side of the organic EL in the second direction;
A drive unit disposed on the first substrate between the first terminal or the second terminal and the organic EL to drive the organic EL to emit light;
A first terminal having a third terminal connected to the first terminal and a fourth terminal disposed on the second direction side of the third terminal and connected to the second terminal; A second substrate through which the organic EL emits light and passes through the sealing member;
Wiring arranged on the second substrate between the third terminal or the fourth terminal and the organic EL when viewed from the normal direction of the second substrate;
An exposure head comprising:   The exposure head according to claim 1, wherein the wiring is electrically connected to the third terminal or the fourth terminal.   The exposure head according to claim 2, wherein the wiring is a control signal line through which a signal for controlling light emission of the organic EL by the driving unit flows.   The exposure head according to claim 2, wherein the wiring is a power supply line that supplies power to the drive unit.   The exposure head according to claim 1, wherein the first terminal and the third terminal are connected by a bump, and the second terminal and the fourth terminal are connected by a bump.   The exposure head according to claim 1, wherein an insulating transparent resin is filled between the sealing member and the second substrate. The organic EL arranged in the first direction is sealed with a light-transmitting sealing member, and is arranged on one side of the organic EL in a second direction orthogonal or substantially orthogonal to the first direction. A first substrate having a first terminal and a second terminal disposed on the other side of the organic EL in the second direction, the first terminal or the second terminal and the organic EL A driving unit disposed on the first substrate to drive the organic EL to emit light, a third terminal connected to the first terminal, and a second direction side of the third terminal A second terminal arranged and connected to the second terminal to support the first substrate, and the organic EL emits light and the light passing through the sealing member is transmitted through the second terminal; The third terminal or the fourth terminal when viewed from the normal direction of the substrate and the second substrate An exposure head having a wiring disposed on the second substrate between the organic EL,
A latent image carrier that is exposed by the exposure head to form a latent image; and
An image forming apparatus comprising:

Images