Printed circuit board, image forming apparatus, and mounting method

Abstract

To make it easier to detect incorrect component placement. [Solution] The system includes a land 416 corresponding to a through-hole 316, a land 417 corresponding to a through-hole 317, a pad 421, a pad 422, a pad 423, and a pad 424. The land 416 includes a 416-1 electrically connected to pad 421, and a land 416-2 electrically connected to pad 422 but not electrically connected to land 416-1. The land 417 includes a land 417-1 electrically connected to pad 423, and a land 417-2 electrically connected to pad 424 but not electrically connected to land 417-1.

Description

Technical Field

[0001] The present invention relates to a printed circuit board, an image forming apparatus, and a mounting method, and more particularly to a printed circuit board used in an image forming apparatus using electrophotography technology, for example.

Background Art

[0002] Conventional printed circuit boards include those that prevent incorrect mounting by devising silk markings when mounting components having a plurality of pins on the board (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as shown in FIGS. 9(b) and 9(c), when mounting components on a board, the mounting position and orientation are not uniquely determined, and there is a risk of incorrect mounting.

[0005] An object of the present invention is to make it easy to recognize incorrect mounting of components.

Means for Solving the Problems

[0006] To solve the above-described problems, the present invention has the following configuration.

[0007] (1) A printed circuit board comprising: a through-hole array including a first through-hole and a second through-hole, wherein the plurality of through-holes are arranged adjacently in the direction of arrangement; a plurality of lands arranged corresponding to each of the plurality of through-hole arrays, wherein the lands include a first land corresponding to the first through-hole and a second land corresponding to the second through-hole; a first pad, a second pad, a third pad, and a fourth pad, wherein the first land comprises a first land portion electrically connected to the first pad and a second land portion electrically connected to the second pad and not electrically connected to the first land portion; and the second land comprises a third land portion electrically connected to the third pad and a fourth land portion electrically connected to the fourth pad and not electrically connected to the third land portion.

[0008] (2) A printed circuit board comprising: a through-hole array including a first through-hole, a second through-hole, and a third through-hole, wherein the plurality of through-holes are arranged adjacent to each other in the direction of arrangement; a plurality of lands arranged in relation to each of the plurality of through-hole arrays, wherein the lands include a first land corresponding to the first through-hole, a second land corresponding to the second through-hole, and a third land corresponding to the third through-hole; and a component having one end mounted on the second through-hole and the other end mounted on the third through-hole, which overlaps with the first through-hole when viewed in a direction perpendicular to the surface of the substrate.

[0009] (3) An image forming apparatus for forming an image on a recording material, characterized in that it comprises a printed circuit board as described in (1) or (2) above. [Effects of the Invention]

[0010] According to the present invention, it is possible to easily recognize incorrect mounting of components. [Brief explanation of the drawing]

[0011] [Figure 1]Schematic diagrams of the laser beam printers in Examples 1 and 2 [Figure 2] Perspective view showing the mounting of printed circuit boards and connector posts for different products in Example 1. [Figure 3] Schematic diagram of the printed circuit board of Example 1 [Figure 4] A flowchart showing the process of assembling the control board from Example 1 into the product. [Figure 5] Schematic diagram of the printed circuit board, connector post, and test circuit of Example 1 [Figure 6] This diagram shows the waveforms of the switch, power supply, and voltmeter of the test circuit during the test in Example 1. [Figure 7] Schematic diagram of the printed circuit board in Example 2 [Figure 8] Schematic diagram of a printed circuit board with the lead jumper of Example 2 mounted. [Figure 9] Perspective view showing conventional mounting of printed circuit board and connector posts. [Modes for carrying out the invention]

[0012] Let's explain Figure 9. Figure 9 shows a front view of a connector post and a top view of a through-hole on a printed circuit board, with lead pins and corresponding through-holes connected by dashed lines. In recent years, the models of image forming machines have diversified, and in the case of printed circuit boards, there is a method of manufacturing multiple models of printed circuit boards by switching the components mounted on the same printed circuit board. Printed circuit boards are provided with through-holes (hereinafter referred to as "through-holes") into which lead pins that will be soldered to the board are inserted. Connector posts with multiple lead pins are mounted on the printed circuit board. A housing (not shown) is inserted into the connector post. In connector posts mounted on printed circuit boards, by making it possible to mount at least two types of connector posts with different numbers of lead pins in the same location, it is possible to reduce unnecessary wires in low-cost models and lower costs.

[0013] Figure 9 shows connector posts mounted on substrate 700. Substrate 700 is provided with, for example, 20 through-holes through which lead pins pass. Hereafter, the 20 through-holes will be denoted as 701 to 720. For example, a substrate 700 used in a high-performance image forming apparatus will be mounted with a connector post 720A having 20 lead pins 1A'l to 20A'l, as shown in Figure 9(a). Here, lead pins 1A'l to 20A'l correspond to through-holes 701 to 720, respectively. On the other hand, a substrate 700 used in a low-cost image forming apparatus will be mounted with a connector post 720B having 16 lead pins 1B'l to 16B'l, as shown in Figures 9(b) and 9(c).

[0014] Since the circuit board 700 has 20 through-holes 701 to 720, a connector post 720A with 20 lead pins 1A'l to 20A'l can be uniquely mounted on the circuit board 700. On the other hand, for a connector post 720B with 16 lead pins 1B'l to 16B'l, the number of through-holes 701 to 720 on the circuit board 700 is greater than the number of lead pins 1B'l to 16B'l on the connector post 720B. Therefore, the mounting position and orientation of the connector post 720B on the circuit board 700 cannot be uniquely determined, and there is a risk of mismounting. For example, in Figure 9(b), the 16 lead pins 1B'l to 16B'l of the connector post 720B are inserted into through-holes 701 to 716 on the circuit board 700. Furthermore, in Figure 9(c), the 16 lead pins 1B'l to 16B'l of the connector post 720B are inserted into the through-holes 705 to 720 of the substrate 700. [Examples]

[0015] (Image forming apparatus) FIG. 1 is a cross-sectional view showing the configuration of a laser beam printer as an example of an image forming apparatus. The laser beam printer 100 (hereinafter referred to as printer 100) includes a photosensitive drum 101 on which an electrostatic latent image is formed, a charging unit 102 that uniformly charges the photosensitive drum 101, and a developing unit 103 that develops the electrostatic latent image formed on the photosensitive drum 101 to form a toner image. The printer 100 also includes an exposure device 114 that irradiates the photosensitive drum 101 with laser light using a laser unit 113 to form an electrostatic latent image on the surface of the photosensitive drum 101. In the printer 100, the toner image formed on the photosensitive drum 101 is transferred by a transfer unit 105 to a sheet P, which is a recording material fed from a cassette 104. The sheet P onto which the toner image has been transferred is conveyed to a fixing device 106, the unfixed toner image is fixed to the sheet P by the fixing device 106, and the sheet P onto which the toner image has been fixed is discharged to a tray 107. The photosensitive drum 101, the charging unit 102, the developing unit 103, and the transfer unit 105 constitute an image forming unit. The printer 100 also includes a power supply device 108, and the power supply device 108 supplies power to a drive unit such as a motor and a control board 109.

[0016] The control board 109 has a CPU 109a as a control unit, and controls an image forming operation by the image forming unit, a conveyance operation of the sheet P, and the like. In the image forming operation, a signal output from the CPU 109a is transmitted from the control board 109 to a laser control board 110 via a wire 111. The laser control board 110 controls the lighting of the laser unit 113 via a wire 112 based on the signal. Note that the image forming apparatus to which the present invention is applied is not limited to the configuration of FIG. 1.

[0017] In Example 1, the specifications of the laser unit 113 are different. For Product A, the laser unit 113A and the laser control board 110A are used, and for Product B, the laser unit 113B and the laser control board 110B are used. Similarly, for the electric wires 111 and 112, for Product A, the electric wires 111A and 112A are used, and for Product B, the electric wires 111B and 112B are used. In Example 1, Product A is more functional than Product B, and the number of wires of the electric wire 111A is 20, and the number of wires of the electric wire 111B is 16, thus reducing the cost of Product B.

[0018] (Control board 109) A part of the control boards 109 of Product A and Product B in Example 1 is shown in FIG. 2. FIG. 2 shows a front view of the connector housing and the connector post, and a top view of the through holes of the printed circuit board, and the lead pins and the through holes corresponding to the lead pins are connected by broken lines. For Product A and Product B, the same printed circuit board 200 is used, and by changing the specifications of the components to be mounted or leaving the unused components unmounted, the control board 109A optimal for Product A and the control board 109B optimal for Product B are manufactured respectively. The printed circuit board 200 is provided with a plurality of through holes through which the lead pins pass, for example, 20 through holes, and these are labeled with numbers 301 to 320. The through holes 301 to 320 (through hole array) are arranged in two rows such that the odd-numbered through holes 301, 303, ···, 319 and the even-numbered through holes 302, 304, ···, 320 are adjacent to each other on the printed circuit board 200 and are arranged in a staggered pattern. Also, in the printed circuit board 200, the surface on which the components are soldered, in other words, the surface opposite to the surface on which the components are mounted, is defined as the solder surface 200A (see FIG. 3). Further, the longitudinal direction of the connector housing and the connector post described later is defined as Dl. The longitudinal direction Dl is also the arrangement direction (array direction) of the lead pins.

[0019] In product A, a connector housing 201A and a connector post 202A are used to connect the electric wire 111A and the control board 109A. The connector post 202A is mounted on the printed circuit board 200 by soldering to form the control board 109A. The connector housing 201A has 20 contact pins 1Ac to 20Ac, which are electrically connected to the electric wire 111A. The connector post 202A, which acts as the first connector, has 20 lead pins 1Al to 20Al, which are soldered to through-holes 301 to 320. The lead pins 1Al to 20Al are also arranged in two rows in a staggered arrangement to fit through-holes 301 to 320.

[0020] Furthermore, the printed circuit board 200 has 20 through-holes 301-320, which is the same number as the lead pins 1Al-20Al on the connector post 202A. Therefore, the control board 109A can uniquely mount connector posts 202A having 20 lead pins 1Al-20Al.

[0021] On the other hand, in product B, a connector housing 201B and a connector post 202B are used to connect the electric wire 111B and the control board 109B. The connector post 202B is mounted on the printed circuit board 200 by soldering to form the control board 109B. The connector housing 201B has 16 contact pins 1Bc to 16Bc, which are electrically connected to the electric wire 111B. The connector post 202B, acting as a second connector, has 16 lead pins 1Bl to 16Bl. Similar to product A, the printed circuit board 200 has 20 through-holes 301 to 320, and the number of lead pins 1Bl to 16Bl on the connector post 202B is less than the number of through-holes 301 to 320. The lead pins 1Bl to 16Bl are also arranged in two rows in a staggered arrangement to match the through-holes 301 to 320.

[0022] Therefore, on the control board 109B, the mounting location of the connector post 202B, which has 16 lead pins 1Bl to 16Bl, on the printed circuit board 200 is not uniquely determined. In Figure 2, an example is shown where the lead pins 1Bl to 16Bl of the connector post 202B are mounted in through-holes 301 to 316, and this state is considered the correct mounting position. However, the mounting location of the connector post 202B on the printed circuit board 200 could also be, for example, through-holes 303 to 318, or through-holes 305 to 320.

[0023] In addition, among the lead pins 1Bl to 16Bl of the connector post 202B, lead pin 1Bl may be referred to as the smallest pin and lead pin 16Bl as the largest pin. The largest pin (16Bl) is the lead pin (first lead pin) located at one end of the longitudinal direction Dl of the connector post 202B among the multiple lead pins of the connector post 202B. The smallest pin (1Bl) is the lead pin (second lead pin) located at the other end of the longitudinal direction Dl of the connector post 202B among the multiple lead pins of the connector post 202B. In addition, lead pin 2Bl may be referred to as the smallest pin and lead pin 15Bl as the largest pin. Furthermore, the first state is defined as the correct mounting state in which lead pin 16Bl of the connector post 202B passes through through hole 316 and lead pin 1Bl passes through through hole 301. The second incorrect mounting state is defined as the condition in which lead pin 16Bl of connector post 202B penetrates a different through-hole than through-hole 316, and lead pin 1Bl penetrates a different through-hole than through-hole 301.

[0024] (Printed circuit board 200) Figure 3 shows a schematic diagram of the solder side 200A of the printed circuit board 200 in Example 1. The through-holes 301-320 in Figure 2 and the lands 401-420 (multiple lands) in Figure 3 correspond in number. For example, through-hole 301 corresponds to land 401, and through-hole 320 corresponds to land 420. That is, the printed circuit board 200 has lands 401-420 with copper foil attached that surround the through-holes 301-320 on the solder side 200A.

[0025] In Example 1, the land 416 (first land) corresponding to lead pin 16Bl, which is the largest pin of connector post 202B, is divided into two parts: land 416-1 (first land portion) and land 416-2 (second land portion). In the direction along the surface of the printed circuit board 200 and in the direction intersecting the arrangement direction, land 416-1 and land 416-2 are positioned at different locations. In the direction intersecting, land 416-1 and land 416-2 are located between pad 421 and pad 422, respectively. The shortest distance between land 416-1 and land 416-2 is 0.3 mm or more. This configuration reduces the possibility of land 416-1 and land 416-2 being soldered together when soldering land 416 to the lead pin. The through-hole 316 corresponding to land 416 is the first through-hole.

[0026] In this case, the imaginary line L1 that divides the two lands 416-1 and 416-2 is parallel to the longitudinal direction Dl (the flow direction in Example 1). Land 416-1 is electrically connected to pad 421 (first pad) with copper foil, and land 416-2 is electrically connected to pad 422 (second pad) with copper foil.

[0027] Furthermore, in the longitudinal direction Dl, land 417 (second land), adjacent to land 416, is divided into two parts: land 417-1 (third land section) and land 417-2 (fourth land section). In the direction along the surface of the printed circuit board 200 and in the intersecting direction that intersects with the arrangement direction, land 417-1 and land 417-2 are positioned at different locations. In the intersecting direction, land 417-1 and land 417-2 are located between pad 423 and pad 424, respectively. The shortest distance between land 417-1 and land 417-2 is 0.3 mm or more. This configuration reduces the possibility of land 417-1 and land 417-2 being soldered together when soldering land 417 to the lead pins. The through-hole 317 corresponding to land 417 is the second through-hole.

[0028] In this case, the imaginary line L2 that divides the two lands 417-1 and 417-2 is also parallel to the longitudinal direction Dl (flow direction in Example 1). Land 417-1 is electrically connected to pad 423 (third pad) with copper foil, and land 417-2 is electrically connected to pad 424 (fourth pad) with copper foil. Pads 421 to 424 are electrodes that serve as contacts for inspection devices such as in-circuit testers that electrically detect mounting defects on the printed circuit board 200 during mounting defect inspection.

[0029] In Example 1, the correct mounting position for the connector post 202B of product B is set to through-holes 301-316, but it is not limited to this. The correct mounting position may also be through-holes 303-318 or through-holes 305-320. Also, in Example 1, pads 421-424 are provided only on one end, but they may also be provided only on the other end, or on both ends. In this case, the through-hole through which the lead pin 16Bl passes is designated as the first through-hole, the through-hole through which the lead pin 1Bl passes is designated as the second through-hole, the land of the first through-hole is designated as the first land, and the land of the second through-hole is designated as the second land. The land located on one end side in the direction of alignment with the first land, and / or the land located on the other end side with the second land, is designated as the third land. The third land may be a land adjacent to the first land and / or the second land, as shown in Figure 3 above.

[0030] (Description of the implementation of the control board 109B) Figure 4 shows the flow (mounting method) for assembling the control board 109B into product B. In S500, the components necessary for the control board 109B circuit are placed on the printed circuit board 200 (first step). In this embodiment, the connector post 202B is installed so that lead pins are inserted into lands 401 to 416 on the printed circuit board 200. In S501, solder is applied to the components installed on the printed circuit board 200. In this embodiment, soldering is performed by flow mounting (second step). Details regarding the flow mounting of the connector post 202B will be described later.

[0031] In S502, the printed circuit board 200 is inspected. This inspection checks whether the components are correctly mounted on the printed circuit board 200 and whether there are any defects in the mounted components (third and fourth steps). If there are no problems as a result of the inspection, the process proceeds to S503. In S503, it is checked whether the connector post 202B is mounted in the correct position. If it is mounted in the correct position, the process proceeds to S504. Details will be described later. In S504, the printed circuit board 200 with the components correctly mounted is assembled into the image forming apparatus as the control board 109B. Note that if there is a problem with the inspection in S502, or if the mounting position is incorrect in S503, the flowchart in Figure 4 is terminated.

[0032] Thus, the mounting method for mounting components onto a printed circuit board 200 includes a first step of passing multiple lead pins through multiple through holes, a second step of soldering multiple lands to multiple lead pins, a third step of connecting an inspection device to the first pad and the second pad and measuring electrical signals, and a fourth step of connecting an inspection device to the third pad and the fourth pad and measuring electrical signals.

[0033] (Flow assembly of printed circuit board 200) In step S501 of Figure 4, the process of flow mounting the connector post 202B onto the printed circuit board 200 will be explained. Figures 5(a) to (f) show schematic diagrams of the printed circuit board 200 and the connector post 202B at each step in Figure 4. Figure 5(a) is a schematic diagram of the printed circuit board 200 in step S500, where the connector post 202B has been inserted into the correct lands. Lead pins 1Bl to 16Bl of the connector post 202B are inserted into lands 401 to 416.

[0034] Figure 5(b) is a schematic diagram of the printed circuit board 200 and connector post 202B flow-mounted in process S502 as shown in Figure 5(a). The flow direction during flow mounting is the longitudinal direction Dl of the connector post 202B. When the connector post 202B is flow-mounted, the lead pin 16Bl of the connector post 202B and land 416-1, and the lead pin 16Bl of the connector post 202B and land 416-2 are connected by solder at land 416. Therefore, since both the two divided lands 416-1 and 416-2 are electrically connected by the same lead pin 16Bl, pads 421 and 422 are electrically connected.

[0035] On the other hand, since land 417 does not have the 17th lead pin of connector post 202B, even with flow mounting, lands 417-1 and 417-2 are not electrically connected by lead pins. Consequently, pads 423 and 424 are also not electrically connected.

[0036] In other words, when lands 416 and 417 are divided into two, if there is a lead pin on the connector post 202B, the pads connected to each of the divided lands are electrically connected. On the other hand, if there is no lead pin on the connector post 202B, the pads connected to each of the divided lands become electrically unconnected.

[0037] Figure 5(d) is a schematic diagram of the printed circuit board 200 and the connector post 202B in which the connector post 202B was inserted into the wrong land during process S500. In this embodiment, lead pins 1Bl to 16Bl of the connector post 202B are inserted into lands 403 to 418.

[0038] Figure 5(e) is a schematic diagram of the printed circuit board 200 and connector post 202B flow-mounted in process S502 as shown in Figure 5(d). The flow direction during flow mounting is the longitudinal direction Dl of the connector post 202B. In Figure 5(e), land 416 is connected to land 416-1 and 416-2 by solder via lead pins (specifically lead pin 14Bl), similar to land 416 in Figure 5(b). Therefore, pads 421 and 422 are electrically connected.

[0039] On the other hand, land 417 in Figure 5(e) differs from land 417 in Figure 5(b) in that a lead pin (specifically lead pin 15Bl) is inserted into it. Therefore, lands 417-1 and 417-2 are connected by solder via the lead pin. Consequently, pads 423 and 424 are electrically connected.

[0040] (Flow assembly of printed circuit board 200) This section describes the mounting inspection of the connector post 202B in S503. Figure 5(c) is a schematic diagram of the printed circuit board 200 with the connector post 202B correctly mounted connected to the inspection circuit 810. The inspection circuit 810 consists of a power supply 800 and a current detection circuit 801 connected in series. The inspection circuit 810 has one end connected to pads 422 and 424, and the other end connected to pads 421 and 423, and the connection between pads 421 and 423 can be switched by a switch 804. More specifically, the switch 804 can switch between the state in which the inspection circuit 810 is connected to pad 421 and the state in which the inspection circuit 810 is connected to pad 423. In Figure 5(c), the switch 804 is connected to pad 421. In this embodiment, the current detection circuit 801 consists of a resistor 802 and a voltmeter 803 connected in parallel.

[0041] Figure 6(a) shows the waveform when the printed circuit board 200 with the connector post 202B of Figure 5(c) correctly mounted was inspected. In Figure 6(a), (i) indicates the state of switch 804 (connected to pad 421, connected to pad 423), (ii) indicates the ON or OFF state of power supply 800, and (iii) indicates the level (H, L) (electrical signal) of voltmeter 803. The horizontal axis represents time.

[0042] First, switch 804 is connected to pad 421, power supply 800 is turned on, and voltage is applied. At this time, since pads 421 and 422 are electrically connected, current flows through resistor 802, and voltage is applied to voltmeter 803. Next, switch 804 is switched to pad 423, and voltage is applied from power supply 800. At this time, since pads 423 and 424 are not electrically connected, no current flows through resistor 802, and no voltage is applied to voltmeter 803.

[0043] Figure 5(f) is a schematic diagram of the printed circuit board 200 with the connector post 202B incorrectly mounted connected to the test circuit 810. The test circuit 810 is the same as in Figure 5(c), so its explanation is omitted. Figure 6(b) shows the waveform when the printed circuit board 200 with the connector post 202B incorrectly mounted as in Figure 5(f) is tested. (i) to (iii) in Figure 6(b) are the same as in Figure 6(a).

[0044] First, switch 804 is connected to pad 421, power supply 800 is turned on, and voltage is applied. At this time, since pads 421 and 422 are electrically connected, current flows through resistor 802 and voltage is applied to voltmeter 803. Next, switch 804 is switched to pad 423 and voltage is applied from power supply 800. At this time, unlike in Figure 6(a), since pads 423 and 424 are electrically connected, current flows through resistor 802 and voltage is applied to voltmeter 803.

[0045] As described above, the voltage measured by the voltmeter 803 when a voltage is applied between pads 423 and 424 is different, which allows for the detection of incorrect mounting of the connector post 202B. Furthermore, this inspection can be performed together with the mounting inspection of other components, thus avoiding significant initial investment. In Example 1, the correct mounting position can be detected by confirming that there is no adjacent 17th lead pin for the connector post 202B, which has 16 lead pins 1Bl to 16Bl.

[0046] Furthermore, land 401 may be divided into two sections, and it may be confirmed that there are lead pins 1Bl (second lead pin) and 16Bl (first lead pin) of connector post 202B, but no 17th lead pin. This allows for confirmation that the number of lead pins in the mounted connector is the correct 16. Furthermore, if the components mounted on the connector post 202B can be properly managed, only one land adjacent to a land to which a lead pin is connected, and to which no lead pin is connected, may be divided into two. Furthermore, the total area (surface area) of the two divided lands may be larger than the area (surface area) of the other lands that were not divided (the third land). This is preferable because it reduces the decrease in connection strength caused by dividing the lands. Furthermore, in flow soldering, dividing the land into two parallel to the flow direction reduces solder bridging when there are no lead pins on the connector post 202B, so it is preferable to divide it parallel to the flow direction. Furthermore, while the land was divided into two in Example 1, the method is not limited to this. The land may be divided into two or more electrodes. Each of the two or more divided electrodes just needs to be electrically connected to a pad (contact). In addition, although the through-holes 301-320 are arranged in a staggered pattern, the odd-numbered through-holes 301, 303, ..., 319 and the even-numbered through-holes 302, 304, ..., 320 may be arranged in two rows so that they form a grid pattern on the printed circuit board 200. Furthermore, although Example 1 was adapted for lead-type connectors, this configuration can be implemented not only for lead-type connectors but also for surface-mount type components.

[0047] As explained above, according to Example 1, by dividing the land on which the connector post is mounted into two and connecting each divided land to a pad, it is possible to determine whether the lead pins of the connector post have been mounted on the land. By using such a configuration, mismounting of connector posts with a small number of pins can be detected at low cost.

[0048] As described above, according to Example 1, it is possible to easily recognize incorrect component mounting. [Examples]

[0049] The image forming apparatus used in Example 2 is the same as in Example 1, and therefore its description is omitted. Similarly, the laser units 113A, 113B, wires 112A, 112B, laser control boards 110A, 110B, wires 111A, 111B, connector housings 201A, 201B, and connector posts 202A, 202B used in Product A and Product B in Example 2 are also the same. For this reason, their descriptions are also omitted.

[0050] (Printed circuit board 500) In Example 2, a printed circuit board 500 is used for control boards 109A and 109B. Figure 7 shows a schematic diagram of the solder side 500A of the printed circuit board 500 in Example 2. The printed circuit board 500 has through-holes 501-520 (multiple through-holes) and lands 601-620 (multiple lands) formed on it for mounting connector posts 202A and 202B. Through-holes 501-520 are the same as through-holes 301-320 in Example 1.

[0051] In Example 2, through-holes 521 and 522, which are different from through-holes 501 to 520, and lands 621 (fourth land) and 622 (fifth land), which are different from lands 601 to 620, are formed on the printed circuit board 500. Lands 621 and 622 are arranged such that a virtual line L3 connecting land 621 and land 622 intersects the longitudinal direction Dl (direction of lead pin arrangement). In Example 2, lands 621 and 622 are formed such that the virtual line L3 is perpendicular to the longitudinal direction Dl.

[0052] In Example 2, a component having lead pins that penetrate lands 621 and 622 is mounted on the printed circuit board 500.

[0053] Figure 8 is a schematic diagram of the lead jumper 523 (jumper wire) in Example 2, mounted so as to cover (or straddle) the through-hole 517 of the printed circuit board 500. Figure 8(a) is a schematic diagram of attempting to mount the connector post 202B in the correct mounting position, and Figure 8(b) is a schematic diagram of attempting to mount the connector post 202B in the wrong mounting position.

[0054] The lead jumper 523 is a component that is mounted on through-hole 518, which is the second through-hole, at one end, and on through-hole 522, which is the third through-hole, at the other end. When viewed in a direction perpendicular to the surface of the printed circuit board 200, the lead jumper 523 is a component that overlaps with through-hole 517, which is the first through-hole.

[0055] As shown in Figure 8(a), when the connector post 202B is mounted in the correct mounting state (first state) and the lead jumper 523 is mounted on lands 621 and 622, the lead jumper 523 covers land 617 (third land). In other words, the lead jumper 523 is positioned to interfere with the connector post 202B when it is attempted to be mounted in the incorrect state (second state), as shown in Figure 8(b).

[0056] Since the lead jumper 523 is machine-mounted, mis-mounting is impossible. By pre-mounting the lead jumper 523, it is impossible to insert the connector post 202B into the through-hole 517. Therefore, the lead pins 1Bl to 16Bl of the connector post 202B can be inserted into the through-holes 501 to 516, in other words, into the correct positions, thus reliably preventing mis-mounting.

[0057] In Example 2, the lead jumper 523 was positioned to interfere with only one side of the connector, but the invention is not limited to this. For example, if there are empty pins at both ends, the lead jumpers may be installed at both ends of the through-hole. That is, a land located on one end side of the first land in the alignment direction, and / or a land located on the other end side of the second land, may be designated as a third land, and the lead jumper may be positioned to cover the third land. In Example 2, a new hole was provided for inserting the lead jumper, but the invention is not limited to this. The lead jumper may also be directly inserted into the through-hole of an unused connector. For example, the lead jumper may be inserted into through-holes 517 and 518.

[0058] In Example 2, the lead jumper 523 was positioned to cover the through-hole 517, but this is not the only option. The lead jumper only needs to prevent the connector from being mounted in the wrong position; it does not necessarily need to cover the through-hole. For example, the thickness of the lead jumper can be used to prevent the connector from being inserted.

[0059] In Example 2, a lead jumper was used, but any component that can interfere with incorrect connector insertion is acceptable. For example, an electronic component with leads may be used instead of a lead jumper. Alternatively, a large chip component may be used to block the through-hole. In this case, it is preferable to use a component that can be mechanically mounted. In Example 2, the configuration was applied to a lead-type connector, but this configuration can be implemented not only for lead-type connectors but also for surface-mount type connectors.

[0060] As explained above, according to Embodiment 2, when mounting connector posts with a small number of pins, the components are positioned in advance to interfere with the connector posts. By using this configuration, it becomes impossible for the worker to insert the connector posts, thus providing a reliable means to prevent incorrect mounting of the connector posts.

[0061] As described above, according to Example 2, it is possible to easily recognize incorrect component mounting.

[0062] This embodiment includes the following configurations and methods. (Composition 1) A through-hole array in which multiple through-holes are arranged adjacent to each other in the direction of arrangement, including a first through-hole and a second through-hole, A plurality of lands arranged in relation to each of the plurality of through-hole arrangements, the plurality of lands including a first land corresponding to the first through-hole and a second land corresponding to the second through-hole, First pad and The second pad, The third pad and The fourth pad and, Equipped with, The first land comprises a first land portion electrically connected to the first pad, and a second land portion electrically connected to the second pad but not electrically connected to the first land portion. The second land comprises a third land portion electrically connected to the third pad, and a fourth land portion electrically connected to the fourth pad but not electrically connected to the third land portion. A printed circuit board characterized by the following features. (Configuration 2) The aforementioned multiple lands include a third land, The surface areas of the first land portion, the second land portion, the third land portion, and the fourth land portion are each smaller than the surface area of ​​the third land portion. A printed circuit board according to configuration 1, characterized by the features described above. (Composition 3) In a direction along the surface of the printed circuit board and in a direction intersecting the arrangement direction, the first land portion and the second land portion are arranged in different positions. In the aforementioned intersecting direction, the third land portion and the fourth land portion are arranged in different positions. A printed circuit board according to configuration 2, characterized by the features described above. (Composition 4) The shortest distance between the first land portion and the second land portion is 0.3 mm or more. The shortest distance between the third land portion and the fourth land portion is 0.3 mm or more. A printed circuit board according to configuration 3, characterized by the features described above. (Composition 5) In the aforementioned intersecting direction, the first land portion and the second land portion are located between the first pad and the second pad, respectively. In the aforementioned intersecting direction, the third land portion and the fourth land portion are located between the third pad and the fourth pad, A printed circuit board according to configuration 4, characterized by the features described above. (Composition 6) A through-hole array comprising a first through-hole, a second through-hole, a third through-hole, and a plurality of through-holes arranged adjacently in the direction of arrangement, A plurality of lands arranged in relation to each of the plurality of through-hole arrangements, the plurality of lands including a first land corresponding to the first through-hole, a second land corresponding to the second through-hole, and a third land corresponding to the third through-hole, A component in which one end is mounted on the second through-hole and the other end is mounted on the third through-hole, wherein, when viewed in a direction perpendicular to the surface of the substrate, the component overlaps with the first through-hole, Equipped with, A printed circuit board characterized by the following features. (Composition 7) In a direction along the surface of the printed circuit board and in a direction intersecting the arrangement direction, the first land is located between the second land and the third land. A printed circuit board according to configuration 6, characterized by the features described therein. (Composition 8) In the aforementioned arrangement direction, at least a portion of the first land, at least a portion of the second land, and at least a portion of the third land are in the same position. A printed circuit board according to configuration 7, characterized by the features described above. (Composition 9) The aforementioned component is a jumper wire. A printed circuit board according to configuration 8, characterized by the features described above. (Composition 10) An image forming apparatus that forms an image on a recording material, A printed circuit board comprising any of the configurations 1 to 9, An image forming apparatus characterized by the following features. (Composition 11) Photosensitive drum and An exposure apparatus that forms an electrostatic latent image on the photosensitive drum, A control unit that controls the exposure apparatus and Equipped with, The control unit is mounted on the printed circuit board. The image forming apparatus according to configuration 10, characterized in that... (Method 1) A mounting method for mounting components onto a circuit board, The aforementioned mounted components are Equipped with multiple lead pins, The aforementioned substrate is Multiple through-holes, including the first and second through-holes, Multiple lands arranged to correspond to the multiple through holes, First pad and The second pad, The third pad and The fourth pad and, Equipped with, The aforementioned multiple lands are A first land for soldering one of the plurality of lead pins mounted in the first through-hole, comprising: a first land portion electrically connected to the first pad; and a second land portion electrically connected to the second pad and not electrically connected to the first land portion; A second land for soldering one of the plurality of lead pins mounted in the second through-hole, comprising: a third land portion electrically connected to the third pad; and a fourth land portion electrically connected to the fourth pad and not electrically connected to the third land portion; Equipped with, The aforementioned implementation method is, The first step is to pass the plurality of lead pins through the plurality of through holes, A second step involves soldering the plurality of lands and the plurality of lead pins, A third step involves connecting the inspection device to the first pad and the second pad and measuring the electrical signal. The fourth step involves connecting the inspection device to the third pad and the fourth pad and measuring the electrical signal, Implementation methods including this. [Explanation of Symbols]

[0063] 200 Printed Circuit Boards 301-320 Through-hole 401-420, 416-1, 416-2, 417-1, 417-2 Land 421-424 pads

Claims

1. A through-hole array in which multiple through-holes are arranged adjacent to each other in the direction of arrangement, including a first through-hole and a second through-hole, A plurality of lands arranged in relation to each of the plurality of through-hole arrangements, the plurality of lands including a first land corresponding to the first through-hole and a second land corresponding to the second through-hole, First pad and The second pad, The third pad and The fourth pad and, Equipped with, The first land comprises a first land portion electrically connected to the first pad, and a second land portion electrically connected to the second pad but not electrically connected to the first land portion. The second land comprises a third land portion electrically connected to the third pad, and a fourth land portion electrically connected to the fourth pad but not electrically connected to the third land portion. A printed circuit board characterized by the following features.

2. The aforementioned multiple lands include a third land, The surface areas of the first land portion, the second land portion, the third land portion, and the fourth land portion are each smaller than the surface area of ​​the third land portion. The printed circuit board according to feature 1.

3. In a direction along the surface of the printed circuit board and in a direction intersecting the arrangement direction, the first land portion and the second land portion are arranged at different positions. In the aforementioned intersecting direction, the third land portion and the fourth land portion are arranged in different positions. The printed circuit board according to feature 2.

4. The shortest distance between the first land portion and the second land portion is 0.3 mm or more. The shortest distance between the third land portion and the fourth land portion is 0.3 mm or more. The printed circuit board according to feature 3.

5. In the aforementioned intersecting direction, the first land portion and the second land portion are located between the first pad and the second pad, respectively. In the aforementioned intersecting direction, the third land portion and the fourth land portion are located between the third pad and the fourth pad, The printed circuit board according to feature 4.

6. A through-hole array comprising a first through-hole, a second through-hole, a third through-hole, and a plurality of through-holes arranged adjacently in the direction of arrangement, A plurality of lands arranged in relation to each of the plurality of through-hole arrangements, the plurality of lands including a first land corresponding to the first through-hole, a second land corresponding to the second through-hole, and a third land corresponding to the third through-hole, A component in which one end is mounted on the second through-hole and the other end is mounted on the third through-hole, wherein, when viewed in a direction perpendicular to the surface of the substrate, the component overlaps with the first through-hole, Equipped with, A printed circuit board characterized by the following features.

7. In a direction along the surface of the printed circuit board and in a direction intersecting the arrangement direction, the first land is located between the second land and the third land. The printed circuit board according to feature 6.

8. In the aforementioned arrangement direction, at least a portion of the first land, at least a portion of the second land, and at least a portion of the third land are in the same position. The printed circuit board according to feature 7.

9. The aforementioned component is a jumper wire. The printed circuit board according to feature 8.

10. An image forming apparatus that forms an image on a recording material, A printed circuit board comprising the one described in any one of claims 1 to 9, An image forming apparatus characterized by the following:

11. Photosensitive drum and An exposure apparatus that forms an electrostatic latent image on the photosensitive drum, A control unit that controls the exposure apparatus and Equipped with, The control unit is mounted on the printed circuit board. The image forming apparatus according to feature 10.

12. A mounting method for mounting components onto a circuit board, The aforementioned mounted components are Equipped with multiple lead pins, The aforementioned substrate is Multiple through-holes, including the first and second through-holes, Multiple lands arranged to correspond to the multiple through holes, First pad and The second pad, The third pad and The fourth pad and, Equipped with, The aforementioned multiple lands are A first land for soldering one of the plurality of lead pins mounted in the first through-hole, comprising: a first land portion electrically connected to the first pad; and a second land portion electrically connected to the second pad and not electrically connected to the first land portion; A second land for soldering one of the plurality of lead pins mounted in the second through-hole, comprising: a third land portion electrically connected to the third pad; and a fourth land portion electrically connected to the fourth pad and not electrically connected to the third land portion; Equipped with, The aforementioned implementation method is, The first step is to pass the plurality of lead pins through the plurality of through holes, A second step involves soldering the plurality of lands and the plurality of lead pins, A third step involves connecting the inspection device to the first pad and the second pad and measuring the electrical signal. The fourth step involves connecting the inspection device to the third pad and the fourth pad and measuring the electrical signal, Implementation methods including this.

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