JPS6389831A - Lens unit - Google Patents

Abstract

PURPOSE:To contrive to reduce a lens unit in size and weight by arranging a flexible light shielding sheet between a lens and a lens unit body. CONSTITUTION:The flexible light shielding sheet 31 is arranged between the lens 30 and the lens unit body 32. Since the sheet 31 is bent, the sheet 31 is moved while being kept at the bent state in accordance with the movement of the lens 30. Thereby, a dead space in the unit can be reduced and the unit is contrived to reduce in size and weight through the unit has the same function as a doucer consisting of a metal plate.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an improvement in a lens unit used in a variable magnification copying machine and the like and which includes a lens movable along an optical axis.

(b) Prior Art In an electrophotographic copying machine, light emitted from a light source is reflected by a document, passes through a mirror and a lens, and exposes a photoreceptor drum. In such an optical system, it is desirable that all the light reflected from the original document passes through the lens, but in reality, some of the light becomes stray light and passes through areas other than the lens to reach the photoreceptor drum. The quality of the image formed on the photosensitive drum is directly affected by the magnitude of this stray light. Conventionally, in order to prevent this stray light from reaching the photoreceptor drum, a light-shielding plate made of a metal plate or the like was installed next to the lens in the lens unit, and this light-shielding plate blocked the light that passed through anything other than the lens. I was doing it.

(C) Problems to be Solved by the Invention However, in a lens unit using a light-shielding plate as described above, it is impossible to avoid an increase in the size of the unit, and furthermore, there are disadvantages in that it is difficult to reduce the weight. In particular, in single-sided variable magnification copying machines, the optical axis moves as the original size changes, so the lens must be movable along the optical axis as well as in a direction perpendicular to the optical axis. However, the size of the unit becomes very large, which increases the dead space within the unit and increases the weight of the unit, making it impossible to achieve a reduction in size and weight.

An object of the present invention is to provide a lens unit that eliminates the above-mentioned drawbacks by replacing the conventional light-shielding plate made of a metal plate with a flexible light-shielding sheet, and which can realize downsizing and weight reduction. It's about doing.

(Means for Solving Problem d1) The present invention is characterized in that, in a lens unit equipped with a lens movable along the optical axis, a flexible light-shielding sheet is disposed between the lens and the lens unit body. shall be.

(e) Function In the lens unit according to the present invention, since a flexible light-shielding sheet is disposed between the lens and the lens unit body, if the sheet is curved, the sheet will move as the lens moves. Move in a curved state. Therefore, the size of the light shielding portion can be reduced while maintaining the same light shielding function as a conventional light shielding plate, and the dead space within the unit can be reduced, making it possible to downsize the entire lens unit.

(f) Embodiment The figure shows an electrophotographic copying machine which is an embodiment of the present invention. This embodiment will be explained below in the following order.

■Appearance (see Figure 1) ■Overall configuration (see Figure 2) ■Operation panel (see Figure 3) ■Lens unit (see Figures 4 and 5) ■Blank lamp unit (see Figure 6)■ Optical device cleaning structure (see Figures 7 to 9) ■ Exhaust structure (see Figures 10 and 11) ■ Lens position warning display control (see Figure 12) External flame and evacuation ■ Appearance No. 1 The figure is an external view of an electrophotographic copying machine which is an embodiment of the present invention. A document cover 2 is supported at the upper part of the copying machine main body 1 at its rear end so as to be openable and closable.

Further, a paper feed cassette 3 is attached to the copying machine main body 1 at the bottom. This paper feed cassette 3 can be selected depending on the paper size to be stored. A paper discharge tray 4 is attached to the left side of the copying machine main body 1. Paper cassette 3
The paper fed from the main body 1 of the copying machine passes through a copying process section in the main body 1 of the copying machine, and is guided to the paper discharge tray 4 via a paper discharge section (not shown). An operation panel 5 is provided at the upper front of the copying machine main body 1, and is equipped with a print switch and a magnification setting lever, as will be described later.

(2) Overall Structure FIG. 2 is a diagram showing the overall structure of the above-mentioned copying machine. A photosensitive drum 10 that rotates in the direction of the arrow in the figure is disposed approximately at the center of the main body 1 of the copying machine. A main charger 111 and a blank lamp unit 1 are arranged around the photoreceptor drum 10.
2, a developing unit 13, a transfer charger 14, a pair of peeling rollers 15, a cleaner unit 16, and a static elimination lamp 17 are provided in this order. A point P in the diagram of the photosensitive drum 10 represents an exposure point, and light from the optical system is incident thereon.

The optical system is composed of a lens unit 20 and a light source unit 21. The lens unit 20 includes a lens 30 that is movable along the optical axis l and also movable in a direction perpendicular to the optical axis l (perpendicular to the plane of the paper), and two reflective mirrors 40 and 41. We are prepared. The lens unit body also consists of a side plate, a lens unit cover that covers the top of this side plate,
and a lens unit base located at the bottom of the side plate. As will be described later, the lens unit cover has a sliding structure and can be opened and closed.

Additionally, an air circulation hole (suction hole) is formed in a part of the lens unit base.

The light source unit 21 includes a light source 21a and a reflector 2.
1b. Note that the copying machine of this embodiment has a movable document table. Therefore, the light source unit 21 and the lens unit 20 are fixed within the copying machine main body 1.

The photosensitive drum 10, main charger 11, and cleaner unit 16 are integrated as a unit, and are detachably attached to the copying machine main body 1. Similarly, the developing unit 13 is also removable from the copying machine main body 1, and two sets of conveying rollers 60 are provided at the lower right side of the photosensitive drum 10, each of which can be replaced as needed. , 61 and a cliff feed path 62 are provided,
Furthermore, a half-moon-shaped paper feed roller 63 is arranged below it. When the paper feed roller 63 rotates once, the top sheet of paper stored in the paper feed cassette 3 is fed and sent to the copying process section by the transport rollers 61, 60 and the transport path 62. A fixing roller 64 is provided on the left side of the photosensitive drum 10. The paper onto which the image has been transferred in the copying process is fixed by the fixing roller 64 and then discharged to the paper discharge tray 4. In this embodiment, the fixing roller 64 also serves as a paper ejection roller. 18 is an exhaust fan.

With the above configuration, when a document is set and the print switch is operated, the document table moves back and forth and the surface of the document is scanned by the light source unit 21. The reflected light from the original passes through the lens unit 20 and is guided to the exposure point P on the photoreceptor drum 10, where a latent image is formed. Next, the developing unit 13
The latent image formed on the photoreceptor drum is visualized by the transfer charger 14, and the image is transferred to the paper feed cassette.
The image is transferred onto the paper conveyed from the gutter 3. The paper then passes through a fixing roller 64, where it is fixed and ejected to the paper ejection tray 4. Further, residual toner is removed from the photoreceptor drum 10 by a cleaner unit 16, and electricity is further removed by a charge removal lamp 17, thereby preparing for the next copying cycle.

■Operation Panel FIG. 3 is a diagram showing the configuration of the operation panel. 70 is a print switch (print key), 71 is a clear key for clearing set number data, 172 and 73 are copy number setting keys during multi-copying, and 74 is a ready lamp indicating a copy ready state. 75 is a display, 76 is an alarm display lamp, 7
7 is an exposure mode setting switch, and 78 is a magnification conversion lever.

The alarm display lamp 76 is a switch that is set to either paper jam or toner. Also, the magnification conversion lever 78
is a switch that sets the magnification in four stages.

■Lens unit ;g per l and 1λ suction Δ samurai amount 1 delivery' pi L and noisy.

FIG. 4 is an external perspective view of the lens unit.

In this lens unit, the lens 30 can be moved to a predetermined position by a lens unit moving mechanism, which will be described later. Flexible light-shielding sheets 31 are provided on both sides of the lens 30 and between them and the lens unit body 32. This flexible light-shielding sheet 31 is for shielding light other than that passing through the lens (stray light). Flexible light shielding sheet 31
The end portions of the lenses are in contact with the inner wall of the lens unit main body 32, respectively. The visibility light-shielding sheet 31 is arranged so as to meander in an inverted S-shape as a whole within the lens unit main body 32. A first slit 33 is provided between the lens 30 and the first reflecting mirror 40, and a second slit 33 is provided in the portion of the lens unit base 34 facing the second reflecting mirror 41.
A slit 36 is provided.

The reflected light from the original is first reflected by the first reflection mirror 40,
The light passes through the first slit 33 and enters the lens 30. The light emitted from the lens 30 is reflected downward by the second reflecting mirror 41, passes through the second slit 36 provided in the lens unit base 34, and reaches the exposure point P of the photoreceptor drum 10.

The lens unit moving mechanism is provided on the lens unit base 34 shown in FIG. 4. This mechanism controls the position of the lens 30 in conjunction with the operation of a magnification conversion lever 78 shown in FIG.

FIG. 5(A) is a diagram showing a lens unit moving mechanism.

The moving lever 100 and the magnification conversion lever 78 are connected by being connected. This moving lever 100 can move in the directions of arrows A and B in the figure. The moving lever 100 is fixed to a slide lever 101 provided along the side plate of the lens unit body 32. This slide lever 101 is supported by a slide lever support member 102 so as to be slidable in the directions of arrows A and B. A bin 103 is attached to the upper end of the slide lever 101.
One end of a substantially square-shaped magnification switching arm 104 is rotatably supported. Magnification switching arm 10
4 is rotatably supported by the bin 105 at its substantially central portion. A long hole 106 is formed at the other end of the magnification switching arm 104. This elongated hole 106 has a bottle 10 in it.
7 is fitted. The bottle 107 is provided on a lens holder 108 that holds the lens 30 so as to protrude toward the front perpendicular to the plane of the paper. The lens holder 108 is attached to the sliding shaft 10
9, and both ends of the sliding shaft 109 are fixed to a support plate 110. The support plate 110 is fixed on the lens unit base 34 at a slight angle. Support plate 1
On the left side of 10, a slightly curved elongated guide a111 is formed. A roller-shaped guided member 112 is fitted into this guide groove 111 . This guided member 112 is attached to one end of an arm 113. Arm 113
A first lens movable member 114 having an inverted letter shape is rotatably connected to the other end by a bottle 115, and a second inverted letter shaped member is further provided at a position symmetrical to this first lens movable member 114. The lens movable member 116 is the first lens movable member 11
4 by a bottle 117. The first of these
The lens movable member 114 and the second lens movable member 1
Long holes 118 and 119 are formed at the tips of the lenses 16, respectively, and bottles 120 and 121 that protrude toward the front side of the lens 30 perpendicular to the plane of the paper are fitted into these long holes 118 and 119, respectively.

The lens 30 is composed of a compound lens body and a case, and each of the bins 120 and 121 is movable in the direction of the arrow in the figure (in the direction of AB force). These bins 120 and 121 are fixed to the lens body.By moving these bins 120 and 121,
The lens body to which the bottle is fixed also moves, and lens 3
oThe overall focal length changes. In other words, the magnification can be changed. Lenses with such a configuration are widely used in variable magnification copying machines and have a well-known structure, so a description thereof will be omitted.

A lens movement limiter 7122 is provided at a position on the opposite side of the lens 30 of the lens holding base 108 via a plate spring 126. Further, a lens position regulating plate 123 is attached to the right side of the sliding shaft 109 in parallel with it. There are four recesses 127 on the left side of this lens position regulating plate 123.
A detection switch 12 is provided in each recess.
4 are arranged. As will be described later, the lens position regulating plate 123 is also provided with four recesses on its right side as shown in the figure. As will be described later, the recess provided on the right side is used when handling inch paper.

When the lens movement regulating bottle 122 is fitted into the recess 127 and the detection switch 124 is pressed, it is possible to detect that the lens holder 108 is at a predetermined position based on the ON signal of the switch. 4 recesses 127
specifies the position of the lens 30 corresponding to the magnification set by the magnification conversion lever 78. In the example shown in the figure, the lowermost concave portion of the lens position regulating plate 123 corresponds to a magnification of Xi, 24, and the one above corresponds to ×1 (same magnification). Furthermore, the top corresponds to a magnification of ×0.8, and the uppermost recess corresponds to a magnification of ×0.8.
It corresponds to a magnification of 7. The position of the lens 3o is determined by which recess the lens movement regulating pin 122, which is fixed to the lens holder 108 when the lens holder 108 slides on the sliding shaft 109, fits into.

FIG. 5(B) shows the state when the lens holding base 108 has moved upward on the sliding shaft 109 and the lens movement regulating pin 122 has fitted into the recess at the top of the lens position regulating plate 123. There is. When the lens holder 108 moves from the state shown in FIG. 5(A) to the state shown in FIG. 5(B), the lens naturally also moves 3 degrees to the upper left. That is, the lens 3o moves parallel to the sliding OJ+ axis 109, that is, about 1 degree relative to the optical axis l. The reason why the lens 30 tilts and moves in accordance with the magnification is because the document placed on the document table is placed on one side. In other words, if the original is placed on a one-sided basis, the center line of the original, and hence the optical axis l, will be shifted between, for example, an 85-sized original and an A4-sized original.

Detection switch 124 arranged in each recess 127
is for detecting that the lens movement regulating pin 122 is located in a predetermined concave portion, and as will be described later, if this switch is not turned on, the display 75 on the operation panel
I am trying to display an error message. By the action of this detection switch 124, the lens 30 is moved to the magnification conversion lever 7.
You can check whether it is in the correct position corresponding to the magnification set in step 8.

Assume that the moving lever 100 is moved in the direction of arrow A from the state shown in FIG. 5 (A). It is operated on the operation panel. When the moving lever 100 moves in the inward direction, the slide lever 101 moves in the direction of arrow A. At this time, the magnification switching arm 104 rotates clockwise about the pin 105. As a result, the lens holder 108 is moved to the sliding shaft 10.
9 in the direction of the arrow, and the lens 30 moves accordingly.
also moves in the direction of the arrow. Also, at this time, the guided member 112 is guided along the guide groove 111, and the arm 113
rotates slightly clockwise as a whole. This operation causes the first lens movable member 114 to rotate slightly clockwise around the pin 115, and the rotational motion is transmitted to the second lens movable member 116 via the pin 117, so that the second lens movable member 114 rotates slightly clockwise around the pin 115. The member 116 also rotates slightly counterclockwise about the bin 125. As a result, pin 120°12
1 moves a little in the B direction and the A direction, respectively, and the lens bodies in the lens 30 in which the bins 120 and 1 21 are provided move in the lens 30 in the arrow B and A directions, respectively. Note that the purpose of moving each lens within the lens 30 by magnification conversion is to adjust the focal length.

Due to the above-mentioned effects, the lens 30 can be placed in a predetermined position to give a confusing feeling. This is because the lens movement regulating pin 122 is pressed in the direction of the lens position regulating plate 123 by the leaf spring 126. The click feeling can also be distorted. The operator can bring the lens 30 to the correct position by stopping the magnification conversion lever 78 at the desired magnification display position, that is, by stopping the operation at the desired magnification display value (l) with a click feeling. At this time, since the lens movement regulating pin 122 is fitted into a recess corresponding to the set magnification, the detection switch 124 disposed in the recess is turned on. If this switch is not on, the lens 30 is not set at the correct position, and the control section displays the display 7.
5 to warn the operator that the magnification conversion lever 78 is not placed in the correct position.

In the lens unit moving mechanism described above, the lens position regulating plate 123 used in this embodiment is provided with recesses on the left and right sides into which the lens movement regulating pins 122 fit. The recessed portion 127 shown on the left side of the figure corresponds to AB type originals such as A4 size and B5 size. Further, the recessed portion 128 provided on the right side corresponds to inch-sized originals. When assembling a copying machine, if the model needs to handle AB series paper, install this lens position regulating plate 123 so that the AB series recess corresponds to the lens movement guide; T11 pin 122. . If the copying machine needs to handle inch paper, the lens position regulating plate 123 is attached so that the inch series recess 128 corresponds to the lens movement regulating pin 122. This lens position regulation plate 1 determines whether the manuscript to be handled is AB type or inch type.
Only the mounting method described in 23 is required, and there is no need to change other elements. Therefore, there is an advantage that the assembly work system is extremely improved. Note that the switches 124 are attached to the back side of the lens position regulating plate 123, but it goes without saying that in order to correspond to the inch system, each switch needs to be attached to a recess corresponding to the inch system.

Furthermore, the lens unit moving mechanism of this embodiment does not use a driving device such as a motor, that is, the lens 30 is linked to the operation of the magnification conversion lever 78 operated by the operator. Moreover, the position of the lens 30 is always set at the correct position by the action of the lens position regulating plate 123 and the lens movement regulating pin 122. Therefore, there is an advantage that the cost can be significantly reduced by eliminating the need for a motor, a sensor for controlling its movement position, a control unit, etc., and the overall size can be reduced since a motor etc. are not required.

■Blank lamp unit Figure 6 shows a structural diagram of the blank lamp unit.

The blank lamp unit 12, as shown in FIG.
A main charger (charging device) 11 that uniformly charges the surface of the photosensitive drum 10 and a developing unit (developing device) 1
3 along the axis of the photoreceptor drum. This blank lamp unit 12 has a total of 5 blank lamps 80, each of which flashes 4ffll independently.
It is equipped with a to 80e. Each blanking lamp removes unwanted charge on the photoreceptor drum surface. Blank lamps 80a to 80d on the left side of the figure remove unnecessary charges depending on the size of the image to be formed on the surface of the photoreceptor drum. Further, one blank lamp 80e on the right side removes unnecessary charges from the reference position portion of the image. In the figure, the position indicated by P on the photosensitive drum 10 indicates the image reference position (the edge of the paper). The position indicated by ■ indicates the end of the separation belt 81. A separation belt 81 is located at the interval t of P-■.The separation belt 81 is for separating the paper after transfer from the photoreceptor drum. As shown in the figure, this separation belt 81 is provided facing one lower end of the photoreceptor drum 10. The end of the paper 82 is placed on the separation belt 81 in the transfer section. That is, the separation belt 81
is interposed between the paper and the photosensitive drum at one end of the paper 82. As a result, the paper 82 after the transfer is forcibly separated from the surface of the photoreceptor drum 10 by the separation belt 81, and is reliably peeled off.

Separation belts of this type are already known.

The blank lamp 80e on the right side of the blank lamp unit 12 removes the electric charges in the area on the right side beyond the image reference position P from the end position (2) of the separation belt 81. This prevents toner from adhering to the portion of the photoreceptor drum 10 that is in contact with the separation heald 81. That is, toner does not adhere to the separation belt 81, and therefore, it is possible to prevent the edges of the paper 82 from being stained by toner stains on the separation belt 81.

Each of the blank lamps 80a to 80e removes charge from a predetermined area on the photoreceptor drum, and the blank lamp unit 12 includes a lamp box 83 having a predetermined shape in order to regulate the charge removal area.

The lamp box 83 has blank lamps 80a to 80.
A room is formed to separate the cells 0e into individual sections, and an opening 84 is provided in the portion facing the photoreceptor drum 10 for passing the light from the lamp. The opening 84 of each room is set to a size to regulate the range of light irradiated by each lamp. As shown in the figure, for example, in a room housing a blank lamp 80d, the size of the opening 84 is such that the irradiation light shown by the hunting part in the figure is produced, that is, the photoreceptor drum l.
The size is set to irradiate from the position al of O to the position a5. Similarly, the size of the opening 84 of the room that houses the blank lamp 80c varies from the a2 position to the a
The opening 8 of the room that accommodates the blank lamp 80b is set to a size that irradiates the area beyond the position 6.
4 is set to a size that illuminates an area from the position a3 to a position near the left end of the photoreceptor drum 10. The opening 84 of the room that accommodates the blank lamp 80a at the far left end is located at the position a5. The size is set to irradiate an area from the position to a position near the left end of the photoreceptor drum 10.

Positions a1 to a6 each indicate the position of the left end of an image formed corresponding to the document size and set magnification. Therefore, for example, if the position of the left end of the image to be formed is a
In the case of 1, all the blank lamps 8.0a to 80d are turned on, and all charges in the area from the position al to the left end of the photoreceptor drum 10 are removed. Further, when the left end position of the image to be formed is at a3, the blank lamps 80a and 80b are turned on, and the blank lamps 80c and 80d are turned off.

Note that the position a5 indicates the left end image position when the image to be formed is A4 size.

Lamp box 8 that houses the blank lamp 80e
The opening 84 of No. 3 is set to a size that removes the electric charge from the area of the photoreceptor that the separation belt 81 faces. That is, the left end of the light emitted from the blank lamp 80e is
As shown in the figure, the size of the opening 84 is set so that the rays irradiate the left end portion 1v of the separation belt 81, and the area from that position V to the right end of the photoreceptor drum is irradiated.

The blank lamps 80a to 80e and lamp box 83 described above are attached to a blank lamp support plate 85. This blank lamp support plate 85 is attached to the frame so as to be parallel to the axis of the photosensitive drum 10. A connector 86 for supplying power to each blank lamp is attached to the right end of the blank lamp support plate 85, and a retaining protrusion 87 for unit positioning that protrudes to the right is provided at a position slightly to the left of the connector 86. ing.

The frame 88 is provided with a main body side connector 89 connected to the connector 86, and further provided with an engagement hole 90 into which the unit positioning engagement protrusion 87 is engaged. One end of the blank lamp unit 12 is aligned by engaging the unit alignment engaging protrusion 87 with the retaining hole 90. When this connection is performed, the connector 86 is connected to the main body connector 8 at the same time.
9, and power is supplied to each blank lamp from the main body side.

FIG. 6(B) shows an external view of the unit positioning retaining protrusion 87 and the vicinity of the retaining hole 90 with which the protrusion is engaged.

After engaging one end of the blank lamp support plate 85 as described above, the blank lamp support plate 8
Tighten and secure the other end of 5.

By the way, if even a small amount of toner adheres to the separation belt 81, the adhered toner will appear as dirt on the paper, so the position of the opening of the lamp box 83 that regulates the irradiation range of the blank lamp 80e is Must be positioned with high precision. That is, the blank lamp unit 12 must be aligned so that the left end of the irradiated light from the blank lamp 80e passing through the opening 84 coincides with the position V of the photoreceptor drum 10. In this case, if the left end of the blank lamp unit 12 is used as a reference for alignment and then the right end of the blank lamp unit is fixed, the length between the left end and position V will be long. Furthermore, errors are likely to occur in the position of the opening 84 that irradiates the light from the blank lamp 80e. However, in this embodiment, since the base position when attaching the blank lamp unit 12 is set at its right end, errors are less likely to occur, and the position of the opening 84 that irradiates the light of the blank lamp 80e is accurately aligned. There is an advantage that

That is, in the blank lamp unit of this embodiment, a retaining protrusion 87 for unit positioning is provided at the end opposite to the position of the separation belt 81, and this protrusion 87 is attached to the frame 88.
Since positioning is performed by engaging the engagement hole 90 of the unit 12, and then the other end of the unit 12 is fixed with a screw, the position of the opening 84 that irradiates the light of the blank lamp 80e is This has the advantage of being correctly aligned without any errors.

In the above embodiment, the retaining protrusion 87 was provided on the blank lamp unit side and the retaining hole 90 was provided on the frame side for positioning, but the reverse may be used.

(2) Structure for cleaning the optical device FIGS. 7 to 9 are diagrams for explaining the structure for cleaning the optical device.

In the electrophotographic copying machine of this embodiment, the portion of the upper plate of the electrophotographic copying machine body facing the light source unit is made freely removable, and the lens unit body portion opposite to this portion is also made freely removable.

FIG. 7 is a diagram showing the structure of the upper plate of the copying machine main body of this embodiment. The copying machine main body top plate 150 has covers 150a and 150b.
, 150c, each part is removable. It is attached using screws and can be easily removed by removing the screws. Note that in order to remove the copying machine main body top plate 150,
This is performed with the document cover 2 open and the document placement table removed.

Among the removable covers 150a to 150C constituting the upper plate 150 of the copying machine main body, the cover 150 located in the center
b is located directly above the light source unit 21, and faces the upper left side of the lens unit 20. As described later,
A cover that can be opened and closed is provided at the upper left side and the upper right side of the lens unit 20.

Due to the above configuration, the document cover 2 is opened and the entire document placement table is removed.
When the cover 150b located at the center is removed, the light source unit 21 is placed directly below it, so the reflector 21b and the light 121a can be easily cleaned from above. It is also possible to remove this light source unit 21.

FIG. 8 is a structural diagram of the lens unit.

As described above, the lens unit 20 includes a lens 30 and two reflective mirrors 40 and 41, which are housed within the lens unit body 32. Lens unit body 32
consists of a side plate 35, a lens unit cover 43 covering the top of the side plate, and a lens unit base 3 located at the bottom of the side plate.
It consists of 4.

A hook portion 44 is formed on the side plate 42 and projects upward, and the lens unit cover 43 is always hooked onto this hook portion 44 as will be described later.

FIG. 9 is a diagram for explaining the opening/closing mechanism of the lens unit cover 43, and FIG. 9(A) is a front view of the main part.

Figure (B) is a plan view of the main part.

A hook portion 44 formed on the side plate of the lens unit body 32 so as to protrude upward includes hook projections 44a and 44b at its front and rear ends. Also,
As shown in FIG. 4B, the lens unit cover 43 has protrusions 43a and 43b that protrude toward the front in the axial direction of the photoreceptor drum.
The hooking protrusion 44a is engaged with the left end a1 of the protrusion 43a of the lens unit cover 43. Further, the hooking protrusion 4.4b is engaged with the right end a2 of the right protrusion 43b of the lens unit cover 43. The lens unit cover 43 is divided into a left side and a right side at point Q in the figure, and the respective ends of the left lens unit cover and the right lens unit throat cover overlap at this Q point. Notches 35a and 35b are formed on both sides of the pull portion 44 of the side plate 35. The length β of the notches 35a and 35b is sufficiently longer than the respective lengths of the protrusions 44a and 44b, and the depth h is such that the protrusions 44a and 44b are sufficiently long. , 44b are set to such a size that the lower ends of the holes do not touch each other.

Next, the opening/closing operation of this lens unit cover will be explained.

Under normal conditions, the hook on the side plate 35 is the protrusion 44a+
44b are protrusions 43a and 4 of the lens unit cover 43.
It is locked to each end aLa2 of 3b. For this reason, the lens unit cover 43 is
cannot be moved in any direction. However, the same figure (A)
As shown in the left lens unit cover 43,
When the portion of the side plate 35 facing the notch 35a is pressed in the direction of arrow A, the portion facing the notch 35a is bent as shown by the two-dot chain line. When the pressing force in the direction of arrow A is increased to the extent that the hooking protrusion 44a is released, the hooking protrusion 44a disengages the protrusion 43a, and the left lens unit cover 43 is It becomes possible to move in the direction of arrow B. That is, by moving in the direction of arrow B while pressing in the direction of A, the lens unit cover 43 can be moved in the direction of arrow B.

This allows the lens unit cover 43 on the left side of the lens unit main body 32 to be opened.

Similarly, the right lens unit cover 43 can also be opened in the direction of arrow C.

As shown in FIG. 7, a light source unit 21 is arranged at the upper left side of the lens unit 20. Also, a cover 15 of the upper plate of the copying machine body located above the light source unit 21
0b is removable. Therefore, this cover 150
By removing b and further removing the light source unit 21, a force in the direction of arrow A shown in FIG. 9 can be applied to the lens unit 20 from above. That is, by removing the cover 150b, the light source unit 21
By also removing the light source unit 21, the lens unit cover 43 on the left side of the lens unit 20 can be opened and the inside of the lens unit 20 can be cleaned. It is sufficient to clean the inside of the lens unit cover by simply removing the left cover, but in this embodiment, as shown in FIG. 7, the right cover 150c of the top plate of the copying machine body can also be removed. There is. Therefore, by removing this cover 1500 and opening the lens unit cover 43 on the right side of the lens unit 20 in the direction of arrow C (see FIG. 9), it is possible to clean the lens unit cover more thoroughly (especially on the right side). becomes.

As described above, in this embodiment, by making the part of the upper plate of the copier main body that faces the light source unit removable, the light source unit 21 can be easily cleaned, and the light source unit 21 can also be cleaned easily. By removing it, the lens unit cover on the left side of the lens unit 20 can also be opened and closed. That is, cleaning inside the lens unit 20 (including cleaning of the lens) can be easily performed. Furthermore, in this embodiment, the upper plate of the copying machine body located above the right side of the lens unit 20 can be removed, and the lens unit cover 43 on the right side can be opened and closed. Clean the inside of the lens unit 20 by removing the lens unit 1500 and opening the lens unit cover 43 on the right side.
Especially on the right side) - layers can be done easily.

■Exhaust structure In the electrophotographic copying machine of this embodiment, air containing ozone and developer generated around the photoreceptor drum, and heat are exhausted to the outside from the exhaust fan through the lens unit. .

FIG. 10 shows how the air containing ozone and developer generated around the photosensitive drum 10 and the heat generated from the fixing roller 64 are exhausted from the lens unit base 34 that constitutes the bottom plate of the lens unit 20. A plurality of suction holes (air circulation holes) 34a are formed in the side plate 35.
An exhaust hole 4 is provided in a portion located below the first reflecting mirror 40.
2a is formed. FIG. 11 is a view of the mirror unit base 34 viewed from below. Note that 36 directs the light reflected from the second reflecting mirror 41 to an exposure point P of the photosensitive drum 10.
As described above, suction holes 34a are provided at 922 locations on the lens unit head 43, and
Further, since an exhaust hole 42a is provided in a portion of the side plate 35 located below the first reflecting mirror 40, the photoreceptor drum 1
Ozone generated around 0, especially main charger 11
Ozone generated from
The air containing the developing agent and the heat generated from the fixing roller 64 enter the lens unit 20 through the suction hole 34a, are carried along the lens unit pulse 34 to the exhaust hole 42a, and are further removed from the air through the suction hole 34a. 42a to the outside of the lens unit 20. Since the exhaust air is further discharged to the outside of the copying machine body 1 by the exhaust fan 18, the interior of the lens unit 20 can be effectively used as an exhaust path, and the lens unit 20 Since the exhaust hole for the air sucked into the interior is located below the first reflecting mirror 40, all of the air that is sucked into the unit passes along the lens unit base 34 and exits the unit from the exhaust hole 42a without moving upwards within the unit. be discharged. For this reason, the air that has entered the lens unit 20 causes the reflection mirrors 40, 41 and the lens 3 to
0 can be prevented from becoming dirty.

■ Lens position warning display control (see Figure 12) In the electrophotographic copying machine of this embodiment, as described above, the position of the lens 30 is controlled by a mechanism that is linked to the operation of the magnification conversion lever 78 without using a motor or the like. Is going. In addition, in order to stop the lens 30 at the correct position when the magnification conversion lever 78 is operated, the lens position regulating plate 1 is attached as shown in FIG. 5(A).
23, and a recess 127 corresponding to each magnification is provided on the side of the lens position regulating plate 123. When the lens movement regulating pin 122 provided on the lens holder 108 that holds the lens 30 is correctly fitted into the recess 127, the correct stopping position of the lens 30 is guaranteed. However, if the stop position of the magnification conversion lever 78 is not correct, the lens movement regulating pin 122 will move into the recess 127 of the lens position regulating plate 123.
There may be cases where it does not fit accurately. In that case, accurate image formation cannot be performed because the position of the lens 30 is incorrect.

Therefore, in the electrophotographic copying machine of this embodiment, the detection switch 124 is arranged in each recess 127 of the lens position regulating plate 123, and the lens movement regulating pin 122 is
When the switch 124 is properly fitted into the recess 127, the switch 124 at that position is turned on. FIG. 12 shows the detection switch 12 when the magnification conversion lever 78 is operated.
4 is a flowchart showing the operation when the switch 4 is not turned on. The electrophotographic copying machine of this embodiment uses a microcomputer as a control section, and all output signals from various switches and sensors are input to this microcomputer.

In FIG. 12, if all of the detection switches 124 are in the OFF state when the magnification conversion lever 78 is operated, it is first determined in step n1 whether or not a copying operation is in progress at that time. If copying is not in progress, proceed to step n4 and display an error (E display) on the display 75 (see Figure 3).
I do. Also, if copying is in progress, proceed as nl-+n2,
Here, the next copy operation instruction flag F is reset.

Further, at n3, the process waits until the copy paper is ejected, and then advances to n4, where an error is displayed. When an error is displayed at n4, the operator can perform F rate conversion at that time and know that the bar 78 is not set at the correct position.

Through the above-described operations, it is possible to easily recognize whether the lens 30 is set at the correct position, giving the operator a sense of security and preventing copy errors and the like.

(g) More than the effects of the invention, especially the above "(e) Effects" and "(f) Examples"
As explained in "■Lens unit", according to the present invention, since the flexible light-shielding sheet is disposed between the lens and the lens unit body, the size of the light-shielding part can be reduced. This has the advantage that dead space within the lens unit can be reduced and the entire lens unit can be made smaller.

[Brief explanation of the drawing]

FIG. 1 shows an external view of an electrophotographic copying machine which is an embodiment of the present invention. FIG. 2 shows a configuration diagram of the electrophotographic copying machine. FIG. 3 shows a configuration diagram of the operation panel of the electrophotographic copying machine. FIG. 4 shows an external perspective view of the lens unit of the electrophotographic copying machine. FIGS. 5(A) and 5(CB) are plan views of the lens unit moving mechanism and diagrams showing the operating state. Figure 6 (A) and (B) show the blank lamp unit 1-
A structural diagram and a perspective view of the main parts are shown. FIG. 7 shows a configuration diagram of the upper plate of the main body of the electrophotographic copying machine. FIG. 8 shows a front structural view of the lens unit. FIGS. 9(A) and 9(B) show a front view and a plan view of the main parts of the lens unit for explaining the lens unit cover opening/closing mechanism. FIG. 10 is a diagram for explaining the exhaust structure of the electrophotographic copying machine. FIG. 11 shows a perspective view of the mirror unit base viewed from below. FIG. 12 is a flowchart showing the operation of the control section when the lens position is incorrect. 20-lens unit, 30-lens, 31-flexible light shielding sheet, 32-lens unit main body. Figure 1 Prisoner 12

Claims (1)

[Claims] (1) A lens unit comprising a lens movable along the optical axis, characterized in that a flexible light-shielding sheet is disposed between the lens and the lens unit body.