JP2849637B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image device such as an LED print head, a contact type image sensor, and a liquid crystal shutter array head.

[0002]

2. Description of the Related Art In image devices such as an LED head, a liquid crystal shutter array head, and a contact image sensor, a substrate on which an image array is mounted is fixed to a base plate with an adhesive or the like. However, it is difficult to control the thickness of the adhesive, and the height position of the substrate fluctuates, resulting in deterioration of image quality. Further, if an adhesive is used, the process must be stopped while waiting for the adhesive to dry and solidify. Also, when an adhesive is used, it becomes difficult to disassemble the image device, and it becomes difficult to repair or replace the board when a defect is found after assembly. In addition, the substrate is warped, and it is difficult to eliminate the warpage of the substrate with an adhesive.

[0003] The mounting accuracy of the substrate is mainly studied in terms of the mounting accuracy in the height direction, and the mounting accuracy in the horizontal direction of the substrate, that is, the positioning of the longitudinal end face of the substrate is hardly studied. When the mounting accuracy of the substrate in the horizontal direction is reduced, the focusing performance between the lens array and the image array is reduced, and the image quality is reduced. Another problem is the electrical connection to the substrate. Conventional connection methods use a flexible printed circuit board (see, for example, JP-A-4-24-2).
25327), the flexible printed circuit board is expensive, and it is difficult to manage soldering to electrodes provided on the board.

Therefore, in order to obtain a low-cost, high-quality image device, the substrate can be bonded to the base plate without using an adhesive, and at the same time, there is a problem of warpage of the substrate, a problem of positioning of the end face of the substrate, and a problem with respect to the substrate. There is a need to solve electrical connection problems.

As a related prior art, it is known that a base plate of an image apparatus and a lens holder of a lens array are separated and provided separately (for example, see Japanese Patent Application Laid-Open No. 2-273258). Further, there is a prior application of the inventors of the present invention in which the surface of the substrate is pressed by a sandwiching piece provided on the base plate, and a clip terminal is connected to an electrode provided on the substrate by soldering (Japanese Patent Application No. 3-34185).
No. 7). However, these prior applications propose that the clip terminal is provided only on the side along one end face of the substrate, and the other end face is pressed by a sandwiching piece provided on the base plate.

[0006]

An object of the present invention is to (1) fix a substrate on which an image array is mounted to a base plate without using an adhesive, correct the warpage of the substrate, and position the end face of the substrate. (2) The positioning of the board and the electrical connection should be performed almost simultaneously, and (3) The board equipped with the control circuit of the imaging device and the board equipped with the image array should be easily connectable. It is in. Another object of the invention of claim 2 is to (4) use a clip terminal having a bifurcated tip to more reliably hold the substrate.

[0007]

An image apparatus according to the present invention comprises a base plate provided with an alignment member at an upper end, a substrate on which an image array is mounted, and a substrate for a control circuit for the image array. The image array substrate is brought into close contact with the main surface, the control circuit board is brought into close contact with the other main surface, and one end surface of the image array substrate is brought into contact with a positioning member of the base plate and positioned. A plurality of clip terminals are provided along one end surface of the substrate, the two substrates are connected, and a large number of other clip terminals are provided along the other end surface of the two substrates.
The two substrates are joined together, and the two substrates are joined together with a large number of clip terminals from both end face sides.

[0008] Here, preferably, two clip terminals, each of which has a forked bifurcated end, are connected in the middle to at least a part of the clip terminals to more reliably hold and connect the substrate. As the image device, an image device such as a liquid crystal shutter array head and a contact image sensor is used in addition to the LED head shown in the embodiment.

[0009]

According to the present invention, the substrate of the image array and the substrate of the control circuit thereof are connected to each other by clip terminals from both sides with the base plate disposed in the middle. Some of the clip terminals are used for electrical connection between these substrates. As a result, a flexible printed board and an adhesive become unnecessary. The substrate on which the image array is mounted is pressed against the base plate by the spring properties of the clip terminals, and the warpage is eliminated.
As a result, the focus performance of the imaging device is improved. In addition, since the two substrates are joined by clip terminals from both sides, they can be firmly joined, and the warpage is thereby eliminated. Further, if a clip terminal is used, mechanical connection and electrical connection can be simultaneously performed by the clip terminal. One end face of the substrate of the image array is brought into contact with a positioning member provided on the base plate to position the end face. As a result, the position of the end face of the substrate of the image array is accurately determined.

In order to more firmly hold the substrate by the clip terminal, it is preferable to use a so-called F-type clip having a bifurcated tip. However, providing the F-shaped branch portions on the upper and lower sides of the clip terminal increases the width of the clip terminal, which is not suitable when high-density wiring is required as in an image device. Therefore, it is preferable to divide the clip terminal into two, separate the terminal for the image array substrate and the terminal for the control circuit, and couple them in the middle. In this case, a clip terminal having a tip branched into two branches is used. Even when using F-shaped clip terminals, it is not necessary to divide all clip terminals into two. In the present invention, clip terminals are provided on both end surfaces of the substrate, respectively, but one terminal is simply for connecting the substrate in principle, and can be arranged at a low pitch. Therefore, such a clip terminal does not need to be divided into two.

[0011]

1 to 6 show an embodiment using an LED head as an example. In FIGS. 1 and 2, reference numeral 2 denotes a base plate made of an engineering plastic such as polyphenylene sulfide or polycarbonate, which is inexpensive and has high rigidity and heat resistance and high processing accuracy. 4 is an image array substrate,
A glass substrate or a glass-glazed ceramic substrate having a constant thickness and high surface smoothness is used. Reference numeral 6 denotes a board on which an image array control circuit is mounted, and an inexpensive plastic printed board is used. 8 is an LED mounted on the substrate 4
In the array, for example, about 40 arrays are linearly arranged. Reference numeral 10 denotes a part of the control IC of the LED array 8. Reference numeral 12 denotes another control IC mounted on the substrate 6.

Numeral 14 designates a positioning member provided on the base plate 2, which exposes a contact portion with the upper end surface of the substrate 4 to serve as a reference surface. Reference numeral 16 denotes a sandwiching piece that presses the main surfaces of the substrates 4 and 6. The sandwiching piece 16 may not be provided. 2
Reference numerals 0 and 22 denote clip terminals.
0 is also used as a wiring between the substrates 4 and 6, and the clip terminal 22 is used only for mechanical coupling of the substrates 4 and 6. For this reason, the clip terminal 22 is called a board fixing clip. Clip terminal 2
0 is arranged at the highest density near the control IC 10 and has a pitch of, for example, about 1 mm. In other parts, the pitch is, for example, about 5 mm. On the other hand, about 5 to 10 board fixing clips 22 may be provided as a whole, and may be arranged at a large pitch. One of the clip terminal 20 and the substrate fixing clip 22 is preferably integrally formed with the base plate 2 or inserted into a hole provided in the base plate 2 after the formation of the base plate 2 to be integrated.

FIG. 3 shows the soldering of the clip terminal 20 and the substrate electrode 30 of the substrate 4. In the figure, reference numeral 32 denotes an insulating film, for example, using a polyimide resin film, and reference numeral 34 denotes a soldering portion using cream solder. Clip terminals 20, 2
2 is set on the insulating film 32 and the clip terminal 2
The cream solder is applied indiscriminately irrespective of whether it is on 0 or 22. Therefore, the application of the cream solder becomes extremely easy.
Next, when the cream solder is melted by a hot air heater or the like, the cream solder escapes from the unfamiliar insulating film 32 and concentrates on the clip terminals 20 and 22 and the substrate electrode 30. Therefore, soldering can be performed simply by applying cream solder indiscriminately and heating with a hot air heater. The insulating film 32 is for separating the common electrode of the image array 4 and its data bus, and is originally required for the substrate 4. Therefore, even if the insulating film 32 is provided, the number of steps does not increase. On the side of the printed circuit board 6, there is no need to provide the insulating film 32 because the affinity between the cream solder and the plastic of the board 6 is poor.
The clip terminals 20 and 22 are set on the printed circuit board 6,
Similarly, cream solder may be applied and soldering may be performed using a hot air heater or the like. The heater is not limited to a hot-air heater, and may be any heater such as an infrared heater that is non-contact and can easily perform local heating.

Applying cream solder and soldering with a hot air heater have the effects of shortening the soldering time, improving work efficiency, and preventing the substrate 4 from being overheated. For example, heating with a soldering iron requires a heating time of 1 minute or more, but a hot air heater only needs to apply hot air of, for example, about 250 ° C. for several seconds, and has an effect of preventing deformation of the substrate 4 due to overheating.

FIG. 4 shows the completed LED head. In the figure, reference numeral 40 denotes a housing in which conductive particles such as metal powder are mixed with engineering plastic such as polyphenylene sulfide and polycarbonate, and also serves as an electrostatic shield because the conductive particles are mixed. 4
Reference numeral 2 denotes a lens array such as a self-focusing lens array, 44 denotes a projection provided on the housing 40, and 46 denotes a metal cover, which seals the inside of the housing 40 to prevent intrusion of toner, paper powder, etc., and acts as an electrostatic shield. I do. As a result, the LED array 8, the control ICs 10 and 12, and the like are protected from noise at the time of charging and development on the photosensitive drum, and also prevent noise generated by the LED array 8 and the like from leaking outside. A pressing member 48 presses the substrate 4 via the substrate 6 against a reference surface provided on the bottom surface of the projection 44. The pressing member 48 may not be provided.

The assembling of the LED head according to the embodiment will be described. The substrates 4 and 6 are set on the base plate 2 and
Is brought into contact with a reference surface provided on the surface of the positioning member 14. Further, the substrates 4 and 6 are temporarily fastened with the sandwiching pieces 16. Next, when the cream solder is applied as described above and soldering is performed with a hot air heater or the like, the attachment of the substrates 4 and 6 to the base plate 2 and the electrical connection therebetween are completed.

FIG. 5 shows an LED for the lens array 42.
4 illustrates the positioning of array 8. The mark “▽” in the figure represents the reference plane, and the number thereof has no relation to the accuracy. Since the image array substrate 4 is pressed by the clip terminals 20 and 22 from both end surfaces, the image array substrate 4 comes into close contact with the base plate 2 and warpage and deformation are corrected. The upper end of the substrate 4 is located on the positioning member 1.
4 abuts against a reference surface provided on the surface of the image array 4, and the horizontal position in the figure of the image array 8 is determined. The substrate 4 comes into contact with a reference surface provided on the bottom surface of the projection 44 by a force acting on the pressing member 48 from the metal cover 46. As a result, the substrate 4 is positioned on the reference surface on the bottom surface of the protrusion 44 in a state in which the warpage and the deformation have been corrected. The base plate 2 with respect to the housing 40
The positioning is performed by a reference surface provided on the side surface of the housing 40. In the figure, a reference surface is provided on the left side surface. On the other hand, the lens array 42 is positioned by the housing 40, and the bottom surface and one side surface of the lens array 42 are positioned by the housing 40. As a result, the vertical distance between the lens array 42 and the LED array 8 is adjusted so that the housing 40
It is determined by the reference plane provided in. As a result, the interval between them becomes constant. The left and right positioning of the lens array 42 and the LED array 8 is determined by bringing the upper end surface of the substrate 4 into contact with a reference surface provided on the surface of the positioning member 14. The position of the positioning member 14 is determined by bringing the base plate 2 into contact with the housing 40, and the left and right positions of the lens array 42 are determined by bringing the side surfaces of the lens array 42 into contact with a reference surface provided on the housing 40. As a result, the lens array 4
The left and right positions of the image array 8 with respect to 2 are also determined accurately.

In the embodiment, the upper end of the substrate 4 is brought into contact with a reference surface provided on the surface of the positioning member 14. Details are shown in FIG. The substrate 4 is cut out from the side on which the LED array 8 is provided, using a diamond cutter or the like. For this reason, the cutting accuracy at the upper part of the end face of the substrate 4 on the side where the diamond cutter is arranged is high, but the cutting accuracy at the bottom of the substrate 4 is low and uneven. Therefore, the upper end of the substrate 4 having high cutting accuracy is brought into contact with the reference surface of the surface of the positioning member 14 so that the upper end of the substrate 4 is not affected by the unevenness of the bottom of the end surface of the substrate 4.
Positioning can be performed.

In addition to the above, there is a problem that the height of the lens array 42 varies. The focus performance of the lens array 42 is
It is determined by the distance between the center of the lens array 42 in the height direction and the surface of the LED array 8. The height of the lens array 42 has various variations. Therefore, preferably, the lens array 42 is selected according to its height, and a spacer is inserted between the housing 40 and the bottom surface of the lens array 42 so as to correct the height variation. If the error in the distance from the center of the lens array 42 in the height direction to the surface of the LED array 8 is ± 100 μm or less, the distance is set between the surface of the photosensitive drum (not shown) and the center of the lens array 42 in the height direction. High focus performance can be obtained if the distance is matched. For this purpose, the variation △ in the width of the lens array 42 in the height direction may be measured, and the mounting interval between the LED head and the photosensitive drum (not shown) may be corrected by △. Assuming that the distance between the surface of the LED array 8 and the center of the lens array 42 in the height direction is H, the distance between the center of the lens array 42 and the surface of the photosensitive drum (not shown) also needs to be H.
Here, when the thickness of the lens array 42 decreases by △, L
The distance between the ED array 8 is reduced by △ / 2, and the distance between the photosensitive drum and the center of the lens array 42 in the height direction is △ /.
It increases by 2 to become H + △ / 2. Therefore, if the mounting interval between the LED head and the photosensitive drum is shortened by 高 い, high focusing performance can be obtained without adjusting the position of the lens array 42 in the height direction with the spacer.

In order to increase the holding strength of the substrates 4 and 6,
A so-called F whose tip is branched into two branches at the clip terminal 20.
Preferably, a mold clip is used. However, the F-type clip is generally wide, and its width is 1 mm or more.
It is not suitable for wiring in an image device requiring an arrangement pitch of about mm. So, like the clip terminal 70 in FIG.
Different clip terminals 70, 70 are used on the substrate 4 side and the substrate 6 side, and these are combined and used. Clip terminal 7 in FIG.
0 can be formed, for example, with a width of about 0.4 mm. Note that, as in the case of the clip terminals 80 shown in FIG. In the case of the clip terminal 80 of FIG.
A terminal of about mm is obtained.

FIGS. 9 and 10 show the connection of the substrates 4 and 6 using the clip terminals 70. FIG. In this case, the clip terminals 70 are soldered to the substrates 4 and 6, respectively, and set on the base plate 2. The lengths of the clip terminals 70 and 70 are set so as to overlap each other, and the overlapped portions are crimped using, for example, a crimp ring 72. FIG. 10 shows the crimp ring 72. In this way, the clip terminals 70 can be connected without heating the image array substrate 4.

FIG. 11 shows another connection method of the clip terminals 70, 70. In this modification, a projection 74 is provided on the base plate 2, and an insertion hole 76 for the clip terminal 70 is provided on the projection 74. The width of the clip terminal insertion hole 76 is
The thickness is set to be slightly smaller than the thickness when two clip terminals 70 and 70 are overlapped, and the curvature is provided so that the width becomes slightly narrower at the center of the hole 76. Then, the clip terminals 70, 70 are soldered to the substrates 4, 6 in advance, and the clip terminals 70, 70 are passed through the clip terminal insertion holes 76. In this case, the clip terminals 70, 70 are pressed and adhered to each other because the width of the insertion hole 76 is narrow, and the clip terminals 70, 70 cannot be removed in any of the upper and lower directions because the width of the hole becomes narrow at the center of the insertion hole 76. Also in the modification of FIG.
There is an advantage that the bonding between 0 and 70 can be performed and the glass substrate 4 is not heated.

FIGS. 12 and 13 show the connection between the clip terminals 120 and 120 using caulking. The clip terminal 120 has a circular overlapping portion, and a small hole 128 is provided at the center thereof. The base plate 2 has a projection 1
22 and a swaging protrusion 124 are provided. The diameter of the caulking protrusion 124 is made to match the diameter of the hole 128 provided in the circular portion of the clip terminal 120. Also in this modification, the clip terminals 120 are soldered to the substrates 4 and 6 and the clip terminals 120 and 120 are overlapped to form the crimping projection 1.
Pass 24. Next, when the caulking protrusion 124 is heated by ultrasonic waves or hot air, the protrusion is deformed to form a caulking portion 126. As a result, the clip terminals 120, 120 are connected and do not come off. In this modified example, local heating by ultrasonic waves or the like is possible, but since heating is involved, the glass substrate 4 may be deformed, which is not preferable as compared with the examples shown in FIGS.

Alternatively, the clip terminals 70, 70 can be soldered at their overlapping portions. However, in this case, it is necessary to preliminarily apply thick solder to the overlapping portion of the clip terminals 70, 70 or to supply the solder from the outside at the time of soldering.
Further, since a heating time of about one minute is required for soldering, heat is transmitted through the clip terminals 70, and the glass substrate 4 may be deformed. Therefore, the clip terminals 70, 70
Is not preferable to be directly joined by soldering.

FIG. 14 shows an F-type clip terminal for a board fixing clip. In the figure, 140 is a substrate fixing clip, 142, 144, 146, and 148 are branches, and 150 is a branch.
Is a root portion, which is cut off after the substrates 4 and 6 are joined. In the board fixing clip 140, for example, the branch 142
And 144 are used to connect to the substrate 4, and branches 146 and 148 are used to connect to the substrate 6. As is clear from the figure, the maximum width A of the substrate fixing clip 140 is large, for example, 1.6.
About 2 mm, which is not suitable for high-density wiring. However, it is sufficient to provide about 5 to 10 board fixing clips 140, and they can be arranged at a low pitch. Therefore, the board fixing clips 140 as shown in FIG. 14 can also be used.

[0026]

According to the first aspect of the present invention, (1) the substrate on which the image array is mounted is connected to the base plate without using an adhesive, and the warpage of the substrate is corrected, and the end surface of the substrate is positioned to improve the focus performance. (2) Substrate positioning and electrical connection are performed almost simultaneously, simplifying assembly, increasing positioning accuracy, and (3) eliminating the need for a flexible printed circuit board for connection. Claim 2
According to the invention of (4), in addition to this, (4) the connection between the clip terminal and the substrate can be further strengthened. In addition, the clip terminals can be arranged at a high density, and can be adapted to an image device requiring high-density wiring.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an image apparatus according to an embodiment.

FIG. 2 is a sectional view of a main part of the image apparatus according to the embodiment.

FIG. 3 is a side view of a main part showing a soldering part in the embodiment.

FIG. 4 is a cross-sectional view of the image apparatus according to the embodiment.

FIG. 5 is a diagram illustrating positioning of the image apparatus according to the embodiment.

FIG. 6 is a diagram illustrating positioning of a substrate end surface in the image apparatus according to the embodiment.

FIG. 7 is a view showing a clip terminal used in the embodiment.

FIG. 8 is a view showing a clip terminal of a modified example.

FIG. 9 is an essential part cross-sectional view showing connection of two clip terminals in the embodiment.

FIG. 10 is an essential part side view showing a connection part of two clip terminals in the embodiment.

FIG. 11 is an essential part cross-sectional view showing connection of two clip terminals in a modified example.

FIG. 12 is an essential part cross-sectional view showing connection of two clip terminals in another modification.

FIG. 13 is a side view of a main part showing a connection part of a clip terminal in another modification.

FIG. 14 is a diagram showing a board fixing clip terminal according to a modified example.

[Explanation of symbols]

 2 base plate 4 image array board 6 control circuit board 8 LED array 10 control IC 12 control IC 14 positioning member 16 sandwiching piece 20 clip terminal 22 board fixing clip 30 board electrode 32 insulating film 34 soldering part 40 housing 42 lens array 44 protrusion 46 Metal cover 48 Pressing member 70 Clip terminal 72 Crimping ring 74 Projection 76 Clip terminal insertion hole 80 Clip terminal 120 Clip terminal 122 Projection 124 Caulking protrusion 126 Caulking portion 128 Hole 140 Board fixing clip 142, 144, 146, 148 Branch 150 Root

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/44 B41J 2/45 B41J 2/455

Claims (2)

(57) [Claims] 1. An image array substrate, comprising: a base plate provided with an alignment member at an upper surface end; a substrate on which an image array is mounted; and a substrate of a control circuit of the image array, wherein the image array substrate is provided on one main surface of the base plate. The control circuit board is brought into close contact with the other main surface, and one end surface of the image array substrate is brought into contact with a positioning member of the base plate to be positioned, and is placed on one end surface of the two substrates. A number of clip terminals are provided along the two substrates to couple the two substrates, and a number of other clip terminals are provided along the other end surface of the two substrates to couple the two substrates, An image apparatus comprising: a plurality of substrates connected to each other by a large number of clip terminals from both end face sides. 2. An image apparatus according to claim 1, wherein a clip terminal, which is formed by connecting two clip terminals each having a bifurcated tip at an intermediate position, is used for at least a part of said clip terminals.