JPH0382582A - Support/current supply mechanism of printing head - Google Patents

Abstract

PURPOSE:To offset the bending of a support member and to reduce the irregularity in the contact pressure of a contact point by arranging a spacer member of which one contact surface is flat and the other contact surface is formed into the protruding surface corresponding to the bending of a support member between a connector and the support member. CONSTITUTION:The spacer 49 arranged so as to be in close contact with the back surface of the protruding part of a connector 48 and the non-mounting surface of a drive circuit board 43 is formed so as the avoid a part where the foot of a contact point row of the connector 48 protrudes to the rear of the drive circuit board 43. A groove 50a is formed to the surface opposed to the space 49 so as to receive the protruding part 49a formed to the spacer 49. At the time of non-load of the connector 48, the spacer 49 is in contact only with the central part of a support member 50 and horizontally holds the connector 48 and the drive circuit board 43 by the opposite surface thereof. At the time of load when a printing head 13 is mounted, the under surface of the spacer 49 comes into close contact with the upper surface of the support member 50 bent by the contact pressure of the contact row 47 to offset the bending of the support member 50 and the connector 48 and the drive circuit board 43 are held horizontally.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a print head having a printing element array used in an image forming apparatus such as a printer, a copier, or a facsimile machine, that is, a heat generating device used in thermal recording or thermal transfer recording. The present invention relates to a support/power supply mechanism for print heads such as element array recording heads, ion flow recording heads, multi-needle electrode recording heads, LED array recording heads, LCD array recording heads, EL light emitting element array recording heads, and inkjet element array recording heads.

[Conventional technology]

Conventionally, as a support/power supply mechanism for a print head used in an image forming apparatus such as a printer, as shown in FIG. 11, a connector 101 in which a large number of needle electrodes are arranged in the longitudinal direction is used to supply power to the print head. A structure configured to do this has been proposed.

That is, in FIG. 11, 102 is a prismatic housing body, and needle electrode holding holes 103 having a large number of small diameter portions at the tip are formed through the housing body 102 in a direction perpendicular to the longitudinal direction of the housing body 102. There is. and each holding hole 1
A needle electrode 104 consisting of a small-diameter portion with a sharpened tip and a large-diameter base end is loosely inserted into the holding hole 103 so that the small-diameter portion partially protrudes from the small-diameter portion of the holding hole 103, and is held. Hole 103
The needle electrode 104 is arranged so as to be slidable within the holding hole 103 and its large diameter proximal end is locked to the small diameter stepped portion of the holding hole 103 so that the needle electrode 104 does not protrude from the holding hole 103. Further, a connection terminal 106 is press-fitted into the upper end of the holding hole 103 with a spring 105 interposed between it and the rear end of the needle electrode 104 so that a part thereof protrudes from the housing body 102. 104 and the connecting terminal 106 are electrically connected via the spring 105, and the needle electrode 104 is connected to the spring 10.
5 to press downward.

The connector 101 with the bottom of the tank is connected to the drive circuit board [10
The connection terminal 106 is soldered to 7 to securely attach it.

Then, this connector 101 is connected via the support member 108,
Pressure is applied to the print head 109 as shown in FIG.
The needle electrode 104 is brought into pressure contact with the print head 109 to supply power while supporting the print head 109. At this time, the support member 10
8 is the housing body 10 of the connector 101 due to contact pressure.
The spring 105 has a small spring constant and a large stroke so that even if the connector 2 is deflected, the uneven contact pressure caused by the variation in the amount of protrusion of the needle electrode 104 of the connector 101 due to the deflection is sufficiently small. By placing
Contact of the connector needle electrode 104 to the contact array of the printed head 109 is ensured.

Furthermore, as shown in FIG. 13, a support/power supply mechanism for a print head has been proposed in which power is supplied to the print head using a connector having a contact array in the form of a leaf spring. That is, the connector 11 includes a leaf spring-like contact array 113 at the tips of two drive circuit boards 111 and 112.
4 are arranged to face each other, and the substrates 111 and 112 are arranged to face each other.
Connect the back side of the connector mounting surface to a strong support member 115.11.
Support with 6. and each contact row 1 of each connector 114
A print head 117 is inserted between the print heads 13 and is pressed against power supply electrode arrays arranged on both sides of the print head 117 to supply power.

[Problem to be solved by the invention]

By the way, the conventionally used connector 101 with multi-needle electrodes shown in FIG. 11 has a large number of parts and uses parts that are difficult to process, which not only increases the cost, but also reduces the number of coils. The fact that a spring is used and that the spring constant must be kept low;
Furthermore, since a sufficient stroke must be provided, the connector itself becomes large in size, which leads to an increase in the size and cost of the entire device.

Furthermore, although the contact pressure of the print head to the electrodes can be ensured, there is a problem in that the connector 101 and the drive circuit board 107 also flex as the support member 108 flexes, putting stress on the electrodes. In addition, it cannot respond to improvements in contact reliability, wider print heads, and increased number of electrodes.

On the other hand, in the print head support/power supply mechanism shown in Fig. 13, the connector itself is simplified and miniaturized, but if such a small leaf spring is used,
There are limits to the stroke and spring constant settings due to the contact pressure and the bending stress limit of the leaf spring. Therefore, variations in the strokes of the contact rows of the connector due to bending or the like greatly affect variations in contact pressure. This poses a problem in that the allowable range of deflection due to contact pressure becomes very small, and as a result, a strong support member is required.

The present invention was made in order to solve the above-mentioned problems in the conventional print head support/power supply mechanism.It has a simple and compact structure, has little variation in the contact pressure of the contacts, and has high contact reliability. It is an object of the present invention to provide a support/power supply mechanism for a print head that can be obtained.

[Means and operations for solving the problems] The outline of the present invention for solving the above problems will be explained based on the conceptual diagram of Fig. 1 (At, (81). 8), a connector 4 having a row of connector contacts 3 for supplying power to the print head 1, a support member 2 that presses and supports the connector 4, and in some cases a drive circuit board [5, an insulating member, etc.] At least one spacer member 6, or in this illustrated example spacer member 6, provided separately between the support member 6, when subjected to a load such that the contact row 3 of the connector 4 generates a predetermined contact pressure. The shape corresponds to the amount of deflection, that is, when there is no load, a gap 7 is formed between the surfaces of adjacent members, and when there is a load, the support member 2 comes into contact with the adjacent member surface due to the deflection of the support member 2, and the support member 2 is deflected. It is also possible to provide a convex surface portion with a shape that absorbs the amount of water.

With this configuration, when the support member 2 is pressed to bring the contact row 3 of the connector 4 into pressure contact with the electrode row of the print head l, the support member 2 is moved by the contact pressure as shown in Figure F. At this time, since the lower surface of the spacer member 6 is provided with a convex surface portion and is formed in a shape corresponding to the deflection of the support member 2, the deflection of the support member 2 is absorbed, and the connector is The stroke of each of the three contacts is kept equal, thus supporting the printhead while ensuring good power delivery with uniform contact pressure in a simple and compact construction.

〔Example〕

Next, examples of the present invention will be described. FIG. 2 is a schematic diagram showing a configuration example of an ionography printer (a printer using an ion flow print head) to which an embodiment of the print head support/power supply mechanism according to the present invention is applied. Reference numeral 11 denotes an image-bearing drum formed by providing a dielectric layer on the outer periphery of a conductive substrate. The drum is rotated clockwise and a latent image is formed by a print head 13 driven by a print head drive unit 12. After being developed by a developing roll 14, the image is transferred onto a sheet of paper 16 by a corona transfer device 15.

The remaining transferred toner on the drum 11 is scraped off by the cleaning unit 1-17, and the residual charge on the drum 11 is neutralized by the static eliminator 18.

Thereafter, images are sequentially formed by repeating this process.

Paper 16 is stored in a paper cassette 19, fed out by a paper feed roller 20, and separated and fed one by one by a retard roller 21. A toner image is transferred by the corona transfer device 15 onto the paper 16 that has reached the transfer unit via the registration rollers 22, and the paper 16 on which the zero image is formed is fixed by the heat fixing unit 23. is the reversing roller 24. Paper ejection roller 25
After that, the paper is discharged onto the paper discharge tray 26 with the image side facing down.

On the other hand, when performing double-sided printing, when the rear end of the paper 16 with an image formed on one side passes through the reversing roller 24, the paper discharge roller 25 reverses, and the paper '16 is passed through the reversing roller 24 to the double-sided paper. It is fed into the conveyance path 27. After passing through the aligner roller 28 and the conveyance roller 29 and reaching the registration roller 22 again, an image is formed on the back side in the same manner as described above, and then the sheet is discharged to the paper discharge tray 26. Note that the control system board and image processing board 30 are arranged above the main body of the apparatus together with the print head drive unit 12 including a print head drive circuit and the like.

3 is an enlarged perspective view of the ion flow print head used in the printer shown in FIG. 2. FIG.

This print head 13 is constructed by pasting a laminated electrode 32 on a base member 31 made of aluminum.

The laminated electrode 32 is formed by laminating a screen electrode 33, an input electrode array 34 in which various input electrodes are arranged in parallel, etc. through an insulating layer, and covering the layer with a protective layer having openings at necessary locations. A printing element array 35 is provided on the screen electrode 33 surface.
are arranged, and drums 1 are arranged at both ends of the screen electrode surface.
A gap spacer 36 is provided to set the distance between the screen electrode 1 and the screen electrode 33 to a predetermined value.

Input electrode rows 34 are formed on two side surfaces (only one side is shown in FIG. 3) adjacent to the screen electrode 33 surface, and laminated electrodes 3 are partially formed on both ends of the side surfaces.
2 is removed and a positioning reference surface 37 is provided. Actually, a positioning reference surface is similarly formed at a position corresponding to the reference surface 37 formed on the illustrated side surface on the side surface not shown, and the positioning reference surface is used as a reference. A laminated electrode 32 is attached to the base member 31, and by bringing this reference surface into close contact with the reference surface on the main body side, the drum 11 is positioned in the tangential direction of the drum. Also, base member 3
1, a hollow part 38 having an opening is formed over the entire length in the longitudinal direction, and this hollow part 38 is used as a guide when attaching the print head 13 to the main body of the attaching/detaching mechanism. There is.

FIG. 4 is a sectional view of the print head drive unit 12, and FIG. 5 is a sectional view of the print head drive unit 1.
Of the two parts, in Figure 0, which is a perspective view of the peripheral part of the slider 56, 41 is a unit frame, and the unit frame 41 holds three boards: drive circuit boards 42 and 43 and a power supply board 44. Each board 42.43.44
They are connected by connectors 45 and 46, respectively. At each output side end of the drive circuit board 42, 43, a connector 48 having a large number of rows of contacts 47, an insulating spacer 49, and a support member 50 are arranged at symmetrical positions with respect to the drum 11. .

The print head 13 is supplied with power while being held between the contact array 47, and is also held between the reference surface 51 and the holding member 52 on the main body side and positioned in the tangential direction of the drum, and is further connected to the drum 11 via the gap spacer 36. The pressure contact determines the position in the normal direction of the drum, that is, the distance from the drum 11.

As shown in FIG. 5, slide rails 55 are attached to both side plates of the unit frame 41, and both ends of a slider 56 are inserted into the slide rails 55.
C is designed to guide this.

A guide 57 having an angular cross-section is attached to the slider 56 so as to be rotatable by a predetermined amount about a pivot shaft 58 . The guide 57 has a heater cover 59 and a heater 60.
A rectangular cylindrical part 61 formed by the guide 57 and the heater cover 59
enters the hollow portion 38 of the print head 13 and functions as a guide when inserting the head 13 into the print head.

Further, an arm 63 that is rotatable about a central shaft 62 supported by the unit frame 41 is engaged with bins 64 provided at both ends of the slider 56, and the arm 63 is rotated by rotating a lever mechanism (not shown). By swinging the slider 63, the slider 56 is slid toward and away from the drum 11 while being guided by the slide rail 55. When the slider 56 moves in the direction approaching the drum 11, the guide 57 moves the drum 1 toward the print.
3 to bring it into contact with the drum 11. At this time, since the guide 57 is rotatably attached to the slider 56, even if the slider 56 is not positioned exactly parallel to the drum 11, the print head 13 can be moved relative to the drum 11. It is designed so that it can be pressed in a parallel state.

The unit frame 41 has reference bins 6 provided on both side plates.
5 and the reference bin 6
It is held so that it can rotate 5 times. The amount of rotation of the unit frame 41 is regulated to an appropriate amount by a regulating member (not shown), so that the print head 1
3 is pressed against the reference surface 51 while the force received from the contact row 47 is canceled out on the upper and lower sides, so that the pressing member 52
The pressing force is sufficient to keep the printing rod 13 in close contact with the reference surface 51 against the rotation of the printing rod 13 due to the weight of the print head drive unit 12.

As shown in FIG. 5, the guide 57 and the heater cover 59
A tapered cap 66 is provided at the tip of the cylindrical portion 61, which functions as a tip guide when the print head 13 is inserted from the direction of the arrow. Further, power is supplied to the heater 60 built in between the guide 57 and the heater cover 59 by a power supply member 67 made of a flexible sheet and copper foil.
is connected to a power supply means (not shown) at the rear end of the slider 56.

FIG. 6 (At, B) is a sectional view showing in detail an embodiment of the print head support/power supply mechanism according to the present invention, and FIG. FIG. 6(B) shows the state under load with the print head attached, and FIG. 7 shows the state under load.
FIG. 3 is a perspective view of the vehicle under no load. The connector 48 is attached to the drive circuit board 43 so that its tip protrudes. The spacer 49 is arranged in close contact with the back surface of the protruding portion of the connector 48 and the non-mounting surface of the drive circuit board 43 to avoid the portion where the legs of the contact row 47 of the connector 48 protrude toward the back surface of the drive circuit board 43. It is formed like this. Furthermore, so that the support member 50 is in contact with the spacer 49,
In addition, it is arranged to support the position where the reaction force of the contact row 47 is applied to the connector 48, and the spacer 49
A groove 50a is formed on the surface facing the spacer 49, and is configured to accommodate a protrusion 49a formed on the spacer 49.

As shown in FIG. 7, the surface of the spacer 49 in contact with the support member 50 is formed into a convex curved surface such that the thickness of the spacer 49 increases at the center.
When the connector 48 is not loaded and is not attached, it contacts the support member 50 only at the center, and the connector 48 contacts the support member 50 on the opposite side.
8 and the drive circuit board 43 are held horizontally. When the print head 13 is mounted under load, the lower surface of the spacer 49 is bent by the contact pressure of the contact array 47, and the supporting member 5 is bent.
The connector 48 and the drive circuit board 43 are held horizontally by being in close contact with the upper surface of the support member 50 and absorbing the deflection of the support member 50. Therefore, connecter 48 to print rad 1
The print head 13 can be supported by contacting the print head 13 with a uniform contact pressure.

However, at this time, the connector 48 and the drive circuit board 43 are kept horizontal, but they are only bent by the maximum value of the deflection of the support member 50, that is, by the difference in wall thickness between the center and both ends of the spacer 49. , moves toward the support member 50 side. Therefore, it must be taken into consideration that the stroke of the contact row 47 of the connector 48 is reduced by this amount.

FIG. 8 is a schematic diagram showing a second embodiment of the invention.

In this embodiment, the main body portion 72 of the connector 71 is thick at the center, and the surface on the side where the contact row 73 is arranged has a convex shape, which allows the position of the contact row 73 to be adjusted. The center part is high. In FIG. 8, 74 is a drive circuit board, and 75 is a support member.

In the print head support/power supply mechanism configured as described above, when the print head is mounted and under load, the support member 75 is bent by the contact pressure of the contact row 73 and the center portion is depressed, so that the contact row 73 is While keeping the stroke of each contact equal over the entire width,
They will be at about the same height.

This embodiment can provide a similar function without providing a separate spacer member unlike the first embodiment.

FIG. 9 (8) is a schematic diagram showing the third embodiment of the present invention, FIG. 9 shows the state in the no-load state, and FIG. 9(B) shows the state in the loaded state. It shows. This example is
The upper surface 81a of the support member 81 that contacts the drive circuit board 82 is formed in advance into a convex shape. Note that 83 indicates a connector.

In the print head support/power supply mechanism configured in this way, when the print head is attached and the load is applied, the ninth
As shown in ) of the figure, the upper surface 81a of the support member 81 becomes a substantially horizontal surface due to the bending of the support member 81, so that the connector 8
3 and the drive circuit board 82 are held horizontally. In this embodiment, the upper surface of the support member 81 may be formed of a set of ribs whose envelope is a convex surface, instead of being an integral convex surface.

In addition, in the second embodiment, it is necessary to allow for deflection of the drive circuit board during load, but in this embodiment,
The advantage is that the drive circuit board remains horizontal even under load, and the number of parts can be reduced.

10 to (C) are schematic diagrams showing a fourth embodiment of the present invention, in which FIG. 10 shows a cross section, FIG. ) are diagrams each showing L12 under load. In this embodiment, connector 91
is attached so as to protrude from the drive circuit board Fi92, as shown in FIG.
A convex surface 93 is formed on the back surface of the more protruding portion and is configured to come into contact with a support member 94 .

Since the support member 94 is usually made of a highly rigid material such as metal, it is difficult to form it into a convex shape as in the third embodiment, but since the housing of the connector 91 is made of resin,
It is relatively easy to form the convex surface 93 on the connector 91 as in this embodiment. In addition, in this embodiment, the back surface of the protrusion of the connector 91 is made into a convex surface 93, and the support member 94 is
Since the straightness of the drive circuit board 92 can be maintained even under load.

〔Effect of the invention〕

As described above based on the embodiments, according to the present invention, the contact pressure of a large number of contacts of a connector to a print head is made uniform with a simple and compact structure, and the print head is supported reliably. A print head support/power supply mechanism with high performance can be obtained.

[Brief explanation of drawings]

FIG. 1(B) is a conceptual diagram for explaining the concept of the print head support/power supply mechanism according to the present invention, and FIG. 2 is an implementation of the print head support/power supply mechanism according to the present invention. FIG. 3 is an enlarged perspective view of the print head portion of the print head support/power supply mechanism shown in FIG. FIG. 5 is a cross-sectional view showing the structure of the head drive unit, FIG. 5 is a perspective view showing the area around the slider in FIG. 4, and FIG. 7 is a cross-sectional view showing the first embodiment in detail; FIG. 7 is a perspective view showing the mode in an unloaded state; FIG. 8 is a schematic diagram showing the second embodiment of the present invention; FIG. 9 (2); ■) is a schematic diagram showing the third embodiment of the present invention, Figures 10 (9) to C) are schematic diagrams showing the fourth embodiment of the present invention, and Figure 11 is a conventional print head support.・A cross-sectional view showing a connector used in the power supply mechanism. FIG. 12 is a schematic diagram showing a conventional print head support/power supply mechanism using the connector shown in FIG. 11. FIG. FIG. 7 is a cross-sectional view showing another example of the structure of the print head support/power supply mechanism. In the figure, 1 is a print head, 2 is a support member, 3 is a connector contact row, 4 is a connector, 5 is a drive circuit board, and 6
11 is a gap, 11 is an image carrying drum, 12 is a drive unit,
13 is a print head, 42.43 is a drive circuit board, 4
7 is a contact row, 48 is a connector, 49 is an insulating spacer, 5
0 is a support member, ? 1.83.91 is a connector, 73 is a contact row, ? Reference numerals 4, 82 and 92 indicate a drive circuit board, 75°, 81° and 94 a support member, and 93 a convex surface.

Claims (1)

[Scope of Claims] 1. In a support/power supply mechanism for a print head having a printing element array on one longitudinal surface and an electrode array for driving the printing element array on the other surface, mounting of the print head a connector having a contact array for supplying power to the electrode array of the print head at a position; a support member provided on the back side of the contact array of the connector for receiving a reaction force of the contact pressure of the contact array; It is disposed between the print heads, and when the print head is not installed, it forms an uneven gap with the adjacent member, and when the support member is deflected due to the print head installed, it may come into contact with the adjacent member or and a convex surface portion having a shape corresponding to the deflection of the support member configured to form a uniform gap. 2. A spacer member is arranged between the connector and the support member, one contact surface of which is flat and the other contact surface of which is a convex surface corresponding to the deflection of the support member, and the convex surface of the spacer member 2. The print head support/power supply mechanism according to claim 1, further comprising a shaped surface portion. 3. The support and power supply for the print head according to claim 1, wherein the surface of the connector facing the print head is a convex surface corresponding to the deflection of the support member, and the convex surface constitutes the convex surface portion. mechanism. 4. A convex surface corresponding to the deflection of the support member is formed on at least a part of the surface of the connector opposite to the surface facing the print head, and the convex surface constitutes the convex surface portion. The support/power supply mechanism for the print head according to item 1.