JPH0242454Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field This invention relates to an optical writing device in a non-impact printer using an electrophotographic method.

Prior Art In recent years, printing devices have been actively developed, and one of them is a laser printer. However, this method uses a laser oscillation device, a modulator, a deflection device, a special lens, etc., making the structure complicated and the entire device large. In this regard, an optical writing head type printer can simplify the structure and reduce the size. However, on the other hand, in order to improve image quality, it is necessary to accurately adjust the focus of the imaging element and the like.

Purpose This invention has been developed in view of the above points, and it makes it easy to adjust the focus of the imaging element before incorporating it into the imaging device main body, and also makes it easy to incorporate it into the imaging device main body. The present invention aims to provide an optical writing device that can improve image quality through accurate focus adjustment.

Configuration An embodiment of this invention will be described based on the drawings. First, Figure 1 shows an optical writing method.
This schematically shows an LED printer. A photoreceptor belt 3 is stretched between a driving roller 1 and a driven roller 2 that are driven in the direction of the arrow. A charging charger 4 that charges uniformly, an optical writing unit 5 that forms an electrostatic latent image on the photoreceptor belt 3 that is charged by selective light emission of an LED (described later), and a developing device 6 that visualizes the latent image. It is provided. Further, a paper feed roller 8 is provided which takes out the transfer paper 7 at a predetermined timing, and the transfer paper 7 taken out by the paper feed roller 8 is sent to the transfer device 11 via a separation roller 9 and a registration roller 10. The developed image on the photoreceptor belt 3 is transferred onto the transfer paper 7 in this transfer device 11 . After transfer, the transfer paper 7 is transferred to the fixing device 1
2, where it is fixed, and the paper is ejected by a paper ejection roller 13. On the other hand, the photoreceptor belt 3 is connected to the static eliminator 1
4. The surface is processed by the cleaning device 15 in preparation for the next image formation. In addition, 16 is the photoreceptor belt 3
This is a back-up roller that prevents dents etc.

Here, the optical writing unit 5 is an LED array head, and as shown in FIG. 2 and FIG.
The optical writing unit 5 is composed of a light emitting unit 20 consisting of a heat dissipation plate 19 etc. attached to the back of the light emitting unit 20, an imaging element unit 21 attached to the lower part of the light emitting unit 20, and a block described later. Built into the main body of the device. In addition,
The units 20 and 21 are elastic seal members 2.
They are connected via 2.

First, the imaging element unit 21 includes a holding member 24 that holds the imaging element, for example, a self-cleaning lens 23 and an insulating brush 25 attached to the lower part of the holding member 24 over the entire circumference. It consists of a brush holder 26. The tip of the insulating brush 25 comes into contact with the surface of the photoreceptor belt 3 to prevent foreign matter such as toner used in the developing device 6 and paper scraps from adhering to the lower surface of the self-cleaning lens 23.

Next, the light emitting unit 20 and the imaging element unit 21 are connected by interposing the sealing member 22 between the holding member 24 and the heat sink 19, and using screws fixed to both ends of the holding member 24. This is accomplished by fitting a compression spring 28 into a pin 27 having a section, fitting these pins 27 into a hole 29 of a heat sink 19, and screwing a nut 30 together. The sealing member 22 is formed into a frame shape with an opening 31 in the center, and a space 32 surrounded by the sealing member 22 and the vertically opposing heat sink 19, holding member 24, etc. is shielded from the outside air. is maintained. Therefore, toner and paper waste are prevented from entering the space 32, and toner and the like are prevented from adhering to the LED 17 on the substrate 18 facing the space 32 and the upper surface of the self-cleaning lens 23. Further, the sealing member 22 is formed of various types of rubber, foamed urethane, etc. that are easily deformable, and the sealing member 22 is
The distance between the light emitting unit 20 and the imaging element unit 21 can be adjusted by compressing and deforming the light emitting unit 20 . Therefore
The optimum distance between the LED 17 and the self-cleaning lens 23 can be adjusted.

A pair of heat dissipation fins 33 having a large height dimension and a plurality of heat dissipation fins 34 having a small height dimension are formed on the back surface of the heat dissipation plate 19 constituting a part of the light emitting unit 20, and further, A duct 35 for blowing cooling air is formed surrounded by a pair of fins 33 and a plate to be described later. Blocks 36 and 37, which are supports, are connected to both ends of the heat sink 19, and the heat sink 19 and the blocks 36 and 37 are connected by a pin 3 having a threaded portion fixed to the heat sink 19.
Attach the compression spring 39 to the block 36,
This is done by fitting the nut 41 into the hole 40 of the pin 37 and screwing the nut 41 onto the threaded portion of the pin 38. Then, depending on the tightness of this nut 41, block 3
The distance between the blocks 6, 37 and the heat sink 19 can be adjusted, and since the blocks 36, 37 are fixedly attached to the main body of the image forming apparatus, which will be described later, the self-opening can be adjusted by adjusting the tightness of the nut 41. The optimum distance between the lens 23 and the photoreceptor belt 3 can be adjusted. Furthermore, these block 3
6 and 37 are plates 4 constituting the duct 35 mentioned above.
2 are connected. Further, the light emitting unit 2
A connection wire 43 is bonded to the electrodes of the LEDs 17 arranged on the substrate 18, which constitutes a part of the substrate 18, and this wire 43 is further connected to a wiring pattern on the substrate 18, and this wiring pattern has a lead wire. 44 is soldered. and,
The lead wire 44 is connected to a connector 45 for connecting to an external drive circuit or the like. Connector 45
are fixedly attached to the side surfaces of the fins 34 located at both left and right ends.

The optical writing unit 5 configured in this way
are the side plates 46 and 47 of the image forming device main body shown in FIG.
The plate 4 is attached to the stepped portion 49 of the rail 48 fixed therebetween.
It is supported by engaging the two bent portions 50. This support is performed by pushing the bent part 50 into the step part 49 from the direction of the arrow A, and inserting the reference pin 51 fixed into one of the blocks 36 into the reference hole which is the attachment part formed on the side plate 46. 5
The optical writing unit 5 is fixed by inserting the reference pin 54 into the reference hole 53 formed in the other block 37 into the reference pin 54, which is a mounting portion fixed to the side plate 47.

A fan motor 55 for blowing cooling air is attached to the outside of the side plate 46, and the air blown from the fan motor 55 passes through the dust 35 from the opening 56 of the side plate 47 to the opening 5 of the side plate 47.
7 and is discharged outside the main body of the image forming apparatus. In this way, since the cooling air is blown through the duct 35 formed on the back surface of the heat sink 19, heat is effectively radiated from the heat sink 19, and the temperature of the LED 17 is prevented from increasing due to the heat generated by the light emission of the LED 17. Prevented.
Therefore, due to the temperature rise of LED17
A decrease in the light emission output of the LED 17 and a decrease in the sensitivity of the photoreceptor belt 3 due to the shift of the emission wavelength to the longer wavelength side are prevented, and a decrease in image quality is prevented.

Further, only the fin 34 is located inside the duct 35, and in particular, the connector 45, which is a large component, is provided outside the duct 35, so that the flow of cooling air is not obstructed, and the fin 34 is provided with the cooling air flowing inside the duct 35. Heat radiation from 34 and 33 is sufficiently performed. Therefore, the temperature of the LED 17 is further prevented from rising, and the image quality is further prevented from deteriorating.

In order to obtain the best image formation state on the photoreceptor belt 3, the focus of the self-occurring lens 23 is adjusted by adjusting the tightness of the nuts 30 and 41, but it is necessary to assemble the optical writing unit 5 into the image forming apparatus body. It's very difficult once you get into it. Therefore, the focus adjustment of the self-occurring lens 23 is performed using an adjustment jig 58 shown in FIG. 5 before assembling the optical writing unit 5 into the main body of the image forming apparatus.

First, the adjustment jig 58 consists of a jig base 59 and a pair of jig side plates 60 and 6 fixed to the jig base 59.
1. The jig base 5 is attached to the upper end of the jig side plates 60, 61.
It consists of a focusing glass 62 etc. fixed in parallel with 9. Then, by inserting the reference pin 51 into the reference hole 63 formed in the jig side plate 60 and inserting the reference pin 64 fixed on the jig side plate 61 into the reference hole 53, the optical writing unit 5 is adjusted to the adjustment jig. 58. Here, the reference hole 63 is formed in the same shape and the same pitch as the reference hole 52, and the reference pin 64 is formed in the same shape and the same pitch as the reference pin 54,
Furthermore, the interval between the jig side plates 60 and 61 is
The interval is set equal to 6,47. Therefore, the optical writing unit 5 can be easily assembled into the adjustment jig 58. Further, the distance between the reference hole 63 and the image forming surface 65 on the lower surface of the focusing glass 62 is set equal to the distance between the reference hole 52 of the side plate 46 and the surface of the photoreceptor belt 3.

After assembling the optical writing unit 5 into the adjustment jig 58, the LED 17 is made to emit light, and the focus of the self-occurring lens 23 is adjusted by turning the nuts 30 and 41 with a spanner or the like while observing the spot on the imaging surface 65 with the rappe 66. I do. When assembled in the adjustment jig 58, it is easy to operate a spanner or the like, and the spot on the imaging plane 65 can be observed, so that focus adjustment can be performed easily and accurately. Since the state in which the optical writing unit 5 is assembled into the adjustment jig 58 is the same as the state in which the optical writing unit 5 is assembled into the main body of the image forming apparatus, the focus adjustment is performed by incorporating the optical writing unit 5 into the adjustment jig 58. By assembling the optical writing unit 5 into the main body of the image forming apparatus, the photoreceptor belt 3
The best imaging conditions are obtained at the top, improving image quality.

Effects With this invention, as described above, by adjusting the focus of the imaging element before incorporating the optical writing unit into the main body of the image forming apparatus, focus adjustment can be performed easily and accurately, and the image quality can be improved. Moreover, since strict precision is not required in the manufacture of each part, each part can be easily manufactured and costs can be reduced.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is a schematic side view of the LED printer, Figure 2 is a vertical side view of its optical writing unit, Figure 3 is an exploded perspective view of the optical writing unit, and Figure 4 is a part of the main body of the image forming apparatus into which the optical writing unit is incorporated. A perspective view showing
FIG. 5 is a longitudinal sectional side view showing the state of focus adjustment of the optical writing unit. 3... Photoreceptor belt (photoreceptor), 5... Optical writing unit, 17... LED (light source), 20... Light emitting unit, 21... Imaging element unit, 23...
... Self-cleaning lens (imaging element), 36-37
... Block (support body), 52 ... Reference hole (attachment part), 54 ... Reference pin (attachment part).

Claims (1)

[Scope of utility model registration request] It supports a light emitting unit equipped with a light source and an imaging element unit equipped with an imaging element located between the light source and the photoreceptor in a stepless manner, and is positioned and connected to the mounting section of the main body of the image forming apparatus. This optical writing unit is produced by providing a support, adjusting the spacing between the light emitting unit and the imaging element unit to fix the positional relationship between them, and connecting the support to the mounting portion. An optical writing device characterized in that it is incorporated into an image device main body.