JPS6385768A - Blank lamp for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To improve the quality of a copy by making a difference in the distance between a photosensitive body and the tip of the second light shielding part, and the distance between the photosensitive body and a light emitting element in a first light emitting element string smaller than a difference in the distance between the photosensitive body and the tip of the second light shielding part, and the distance between the photosensitive body and a light emitting element in a second light emitting element string. CONSTITUTION:When a difference in the distance between a photosensitive body 110 and a tip 32a of a diaphragm 32, and the distance between the photosensitive body 110 and each LED in an LED string (a), and a difference in the distance between the photosensitive body 110 and the tip 32a of the diaphragm 32, and the distance between the photosensitive body 110 and each LED in an LED string (B) are denoted as Da and Db, respectively, Da<Db is set. Emitted light beams of LEDs 6a-16a are not affected by the diaphragm 32, therefore, border lines 40a, 40b in the horizontal direction of an exposure area 40 become not waveforms but straight lines, and on the other hand, emitted light beams of LEDs 5b, 17b are affected by the diaphragm 32, therefore, border lines 40c, 40d in the vertical direction of the exposure area 40 become straight lines. In this way, the border lines in the vertical direction and the horizontal direction of a latent image forming area and the exposure area can be made not waveforms but in straight lines.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a blanking lamp for an electrophotographic copying machine.

(Prior Art) -A schematic structure of an electrophotographic copying machine is shown in FIG. An original stacking table 112 is arranged at the upper part of the main body, on which an exposure device 111 is arranged. Exposed portion of photoreceptor 110 (n-source portion 118)
A charger 114 is provided on the upstream side in the rotational direction, and a developing device 113 is provided on the downstream side. Development equipment r! 1
Below the photoconductor 110 on the downstream side of 113, there is a
A separation device 115 is provided. The transfer/separation device 1
A cleaning device 116 is provided between the charger 15 and the charger 114.
is installed. Photoreceptor 110 and transfer/separation device 11
A conveyance path for conveying the transfer paper 117 in the rotational direction of the photoreceptor 110 and in the forward direction is formed between the transfer paper 117 and the photoreceptor 110 .

In such an electrophotographic copying machine, the blank lamp 10
0 indicates the exposed portion 11 of the photoreceptor 110, as shown in FIG.
8, that is, between the exposure section 118 and the developing device 113.

As shown in FIG. 10, the blank lamp 100 has a housing 101 in which a large number of light emitting elements, such as LEDs 102 (FIG. 11), are arranged in a row, and a partition plate 103 is provided between each LE0102. ing. These housing 101 and partition plate 103 are made of a material that does not easily transmit light, such as Noryl resin or AC3 resin.

Each LED 102 is arranged to face the surface of the photoreceptor 110 so that the direction of the LED array is perpendicular to the rotation direction A of the photoreceptor. Each LED can be independently controlled to emit light, and the control is performed by a control processor (not shown) of the copying machine.

The blank lamp 100 exposes a specific area on the surface of the photoreceptor 110 that is uniformly charged by the charger 114 to remove static electricity from the area. Paper size cut, (llj) l
Used for collection I (1!DIT), etc.

An outline of each function is explained below.

(a) Leading edge margin or trailing edge margin In the developed view of the photoconductor 110 shown in FIG. Exposure is performed to form an exposed region 130 (hunted in the figure), and the exposed region 130 is neutralized. This exposure is all L E
This is done by emitting light from D102. With this static elimination,
The leading edge of the transfer paper is prevented from adhering to the photoreceptor 110 in the downstream transfer section, and the transfer paper can be easily peeled off from the photoreceptor.

(BL Copy Paper Size In a copying machine having a cut enlargement or reduction function, even when performing reduction copying, the photoreceptor 110 is uniformly charged by the charger 114. Therefore, the reduced original shown in FIG. Toner also adheres to the surface of the photoconductor 110 other than the area 140 (indicated by a dashed line) where an electrostatic latent image is formed.Therefore, the surface of the photoconductor other than the area is exposed by emitting light from a blank lamp 1000. forming a region 141;
The exposed area 141 is neutralized. This exposure consists of: 1. Initially, all the LEDs 102 are made to emit light to form the above-mentioned leading edge margin;
■Next, L above the area 140 where the electrostatic latent image of the document is formed.
The ED is turned off and only the other LEDs are lit.
(2) When the area 140 passes under the blank lamp 100, all the LEDs are turned on again.

This static elimination prevents toner from adhering to the exposed area 141, thereby preventing waste of toner and increased burden on the cleaning device 116 due to adhesion of unnecessary toner.

(C) Collection of &I (EDIT) For example, if it is not necessary to copy the central part of the original, copy the part 1 corresponding to the central part of the area where the electrostatic latent image of the original is formed.
50 (indicated by a two-dot chain line in FIG. 14) is exposed by the blank lamp 100 to form an exposed region 151, and the exposed region 151 is neutralized.

This exposure is performed by causing only the LED 102 located above the central portion to emit light when the portion 150 corresponding to the central portion reaches below the blank lamp 100, and by turning off the LED 102 when the portion 150 passes by.

As a result, toner does not adhere to the exposed area 151,
The portion of the transfer paper corresponding to the center portion of the original is blank.

In this way, the blank lamps 100 are arranged L E
It functions by selectively causing light emitting elements such as D 102 to emit light.

(Problems to be Solved by the Invention) As described above, in the conventional blank lamp, the row of LEDs 102 arranged at right angles to the rotation direction A of the photoreceptor 110 is surrounded by the housing 101, and each LED102
There is a partition plate 103 in between. is installed. For this reason,
In the exposure area 130, 141, 151, the part directly below each of the LEDs 102 emitting light and the area directly between each of the LEDs 102 emitting light are separated by the partition plate 103.
Differences in illuminance occur due to the influence of In other words, the illuminance is strong in the area directly below the emitting LED, and the area directly below the emitting LED is
The illuminance is weak in the part directly under the partition plate 103 between D.

Therefore, the exposure areas 13Q, 1 in a direction perpendicular to the rotational direction of the photoconductor 110 (hereinafter referred to as "lateral direction")
The boundary line between 41.151 and the latent image forming area becomes a waveform. In FIGS. 12 to 14, the boundaries are marked with symbols 130a, 141a, 141b, and 151.
a, 151b are attached.

Therefore, the toner adheres along the waveform. As a result, the waveform also appears in the resulting copy, resulting in a problem that the copy quality deteriorates.

Note that a direction parallel to the rotation direction A of the photoreceptor 110 (hereinafter referred to as "
Since the boundary lines 141c, 141d, 151c, and 151d between the exposure area and the latent image forming area in the "vertical direction" are linear, the above-mentioned problem does not occur in this direction.

The present invention solves the above-mentioned conventional problems, and its purpose is, for example, to improve the vertical alignment between the exposure area and the latent image forming area in an electrophotographic copying machine having functions such as editing. It is an object of the present invention to provide a blank lamp for an electrophotographic copying machine that can make not only the boundary line but also the horizontal boundary line straight.

(Means for Solving the Problems) The blank lamp of the present invention is a blank lamp provided facing a photoreceptor of an electrophotographic copying machine, and is substantially perpendicular to the direction of movement of the photoreceptor. a first light-emitting element row and a second light-emitting element row arranged in parallel extending in the direction; a first light-shielding section provided around and between the two light-emitting element rows; A second light-shielding section provided between each light-emitting element in the element row, and a control means for controlling light emission of each light-emitting element, and a tip of the first light-shielding section and a tip of the second light-shielding section. An opening facing the photoreceptor is formed corresponding to each light emitting element, and the distance between the photoreceptor and the tip of the second light shielding part, and the distance between the photoreceptor and the first light emitting element row are determined. The difference between the distance between the light-emitting elements in the second light-emitting element row is the difference between the distance between the photoreceptor and the tip of the second light-shielding part and the distance between the photoreceptor and the light-emitting elements in the second light-emitting element row. The difference is made smaller, thereby achieving the above objective.

(Example) Examples of the present invention will be described below.

FIG. 1 shows an embodiment of the blank lamp of the present invention; FIG. 1(a) is a perspective view of this embodiment, and FIG.
Figure a) is a front view, and figure (C) is a sectional view taken along line CC in figure (b).

The blank lamp 30 of this embodiment has two lamps arranged vertically in parallel.
LED array aSb. The LED row a has 20 LEDs 1a to 20a arranged in one direction, and the LED row a has 20 LEDs 1b to 20b arranged in one direction.
They are arranged parallel to the ED column a. LED row a,
b is housed in a housing 31 that is a molded product of synthetic resin. The housing 31 has a partition wall 31b that blocks light between both the LED rows. Therefore, the housing 31 blocks light around both LED rows and between both LED rows. Temporary partitions 32 made of synthetic resin are disposed between the LEDs in each of the LED rows a and b to block light between the LEDs.

Both rows a are separated by the housing 31 and each partition plate 32.

Rectangular cylindrical chambers are formed to accommodate the LEDs 1a to 20b respectively. LEDs 1a to 20b in both rows a and b
Two corresponding L's (having the same numerals in the reference numerals)
The EDs are located in vertically adjacent rooms. The tip 31a of the housing 31 and the partition plate 3 are located at one end of the room.
An opening is formed by the tip 32a of each LE.
Light D is irradiated through the aperture. Furthermore, housing 3
The tip 31a of the temporary partition 32 protrudes from the tip 32a of the temporary partition 32. As shown in FIG. 1(C), the arrangement positions of the LEDs 1a to 20a of the LED row a are closer to the tip 32a of the partition plate 32 than those of the LEDs 1b to 20b of the LED row. has been done.

As shown in FIG. 11, such a blank lamp 30 is disposed in a direction perpendicular to the rotational direction (horizontal direction) of the photoreceptor 110, facing the surface of the photoreceptor 1100 that rotates at a constant speed. In this case, the LED row a is placed on the upper side (that is, upstream in the rotational direction of the photoreceptor 11G), and the LED row a is placed on the lower side (downstream in the rotational direction of the photoreceptor 110).

Therefore, the difference between the distance between the photoreceptor 110 and the tip 32a of the partition plate 32 and the distance between the photoreceptor 110 and each LED in the LED row a is Da, and the distance between the photoreceptor 110 and the partition plate 32 is Da.
If Db is the difference between the distance between the two ends 32a and the distance between the photoreceptor 110 and each LED in the LED array (see FIG. 1C), then Da<Db.

In addition, the distance from the upstream end of the opening on the LED row a side to the upstream end of the opening on the side where LED rows are arranged is x (am), and the distance from the upstream end of the opening on the LED row side to the downstream end y (am
), and the surface @ peripheral speed of the photoreceptor 110 is v (
a++s/s).

Irradiation of the photoreceptor 110 by the light emitted from LEDs 1a to 20a of LED row a and LED row b (7) LED
The light emission from lb to 20b will be compared using FIG.

FIG. 3 shows a state in which an exposure area 40 is formed in the center of the photoreceptor 110 by the blank lamp 30, as will be described later. It shows the light emitting state of the LED when it is below.

As mentioned above, since the distance Da between each LED in the LED row a and the tip 32a of the partition plate 32 is small, the distance Da between each LED in the LED row a is small.
The light emitted from each LED is irradiated onto the surface of the photoreceptor 110 without being affected by the partition plate 32. In other words, in spite of the presence of the partition plate 32, the light emission from each of the LEDs 1a to 20a is caused by the partition plate 32 in the lateral direction of the surface of the photoreceptor 110, even in the portion immediately below the emitting LED.
The area immediately below is equally irradiated.

On the other hand, each LED 1b to 20b of the LED row and the partition plate 3
2 and the tip 32a is large, so the LED
Irradiation of the surface of the photoreceptor 110 by the light emitted from each LED in the row is influenced by the partition plate 32 .

That is, in the vertical direction of the surface of the photoreceptor 110, the light emitted from each of the LEDs 1b to 20b in the LED array is regulated by the tip 32a of the partition plate 32 and irradiated onto the surface of the photoreceptor 110.

A circuit diagram of such a blank lamp 300 is shown in FIG. 4, and two corresponding LEDs of each of the LEDs 1a to 20b constitute a parallel circuit. The anodes of both LEDs in each parallel circuit are connected to the + side of a power supply (not shown) via a common resistor R. The cathode of each LED is connected to the collector of each of the transistors Tla to T20b. The emitter of each transistor Tla''T20b is directly connected to one side of the power supply.

Further, a control signal from a control processor (not shown) of the main body of the copying machine is inputted to the base of each transistor Tla =T20b via each terminal Bla =B20b.

Therefore, for example, when the control signal to the terminal Bla is high, the transistor Tla is turned on and the LEDla emits light. Light emission from other LEDs is performed in the same manner.

How to control the blank lamp 30 having such a configuration,
Using FIG. 5 and FIG. 6, the central portion of the photoreceptor 110 (
An editing function for forming an exposure area 40 in a portion (approximately corresponding to the LED rows a to 17a of the blank lamp 30) will be explained by taking as an example.

(1) Time during which the portion A of the photoreceptor 110 is located below the blank lamp 30. Then all terminals Bla ”B2
0b is set to lo-, and all transistors Tla =
T20b is off, and all LEDs 1a to 20b are not emitting light.

(2) When the photoreceptor 110 rotates and the mouth portion is located below the LED row a of the blank lamp 30 (time 1+),
Terminals B6a to B16a become high, transistors T6a to T16a turn on, and LED of LED row a
6a to 16a emit light.

(3) After tx (=x/v) seconds, when the mouth reaches below the LED array (time tz), terminals B5b and B17b
becomes high, transistors T5b and T17b turn on, and LEDs 5b and 17b of the LED array also emit light. LED6a.

The state in which 16a and LEDs 5b and 17b are emitting light is as follows.
This continues until the next step (4).

(4) When the photoreceptor 110 rotates and the second part reaches the bottom of the LED array (time t), terminals B5b and B17b
becomes low-, transistors T5b and 17b are turned off, and LEDs 5b and 17b do not emit light.

(5) After ty (=y/v) seconds, when the second part reaches the bottom of LED row a, at time t4), terminals B6a to B16a become low, transistors T6a to T16a turn off, and LEDs 6a to 16a also turn off. The light will no longer emit light.

The LEDs that emit light in a controlled manner as described above are those of LED row a (LE D6a to 16a) except for both ends in the lateral direction (LEDs 5b and 17b).
The light emission of ~16a is not affected by the partition plate 32, as described above, and is therefore not influenced by the lateral boundary line 4 of the exposure area 40.
0a and 40b are not waveforms but straight lines.

On the other hand, both ends of the LED emitting light (LED5b).

17b) is an LED array. The L E D5b
, 17b is affected by the partition plate 32, so
Exposure area 40 formed by the LEDs 5b and 17b
The vertical boundary lines 40c and 40d are straight lines.

Next, a control method when forming exposure areas mutually over the entire lateral direction of the photoreceptor 11G, such as the leading end margin, will be explained using FIGS. 7 and 8.

(1) When the portion E of the photoreceptor 110 reaches below the blank lamp 30 (time t + *), the terminal B1a=B2
0a becomes high, transistors T1axT20a
is turned on, and all LEDs 1a to 20a of LED row a emit light.

(2) After tx (=x/v) seconds, when the part E reaches the bottom of the LED array (time tII), the terminal Blb-B20b
becomes high, the transistor Tlb NT20b turns on, and all the LEDs 1b to 20b in the LED array also emit light. The state in which all LEDs 1a to 20b are emitting light is as follows (3
) will continue until

(3) When the photoconductor 110 rotates and reaches the bottom of the LED array, the terminal Blb-B20b becomes low, the transistor Tlb-T20b turns off, and the LEDs 1b to 20b emit light. It disappears.

(4) After tyKy/v) seconds, when the part reaches below the LED row a (time t13), the terminal Bla-B20a becomes lO-, the transistors T1a=T20a turn off, and the LEDs la-20a also emit light. I won't.

In this way, all L E D 1a to 20a of LED row a
Since the light is emitted over the entire exposure area, the horizontal boundary m50a of the exposure area 50 is a straight line.

In the embodiment shown in FIGS. 7 and 8, both LED rows a and b are made to emit light, but it is also possible to make only LED row a emit light. A similar effect can be obtained.

In the conventional examples and examples described above, the number of LEDs in each LED row is assumed to be 20 to simplify the explanation.However, in an actual blank lamp, the number of LEDs used as light emitting elements is 20. More than 1. Usually, about 76 LEDs are used in an A3 size copier.

(Effects of the Invention) As described above, in the blank lamp of the present invention, the vertical and horizontal boundaries between the latent image forming area and the exposure area can be straight lines instead of waveforms.

Therefore, in the electrophotographic copying machine equipped with the blank lamp of the present invention, no waveforms appear on the resulting copies, and the copy quality is improved.

Figure 1 shows an embodiment of the blank lamp of the present invention; Figure (a) is a perspective view of this embodiment, Figure 1) is a front view of Figure (a), and Figure (C) is a cross-sectional view taken along the line CC in Figure (b), Figure 2 is an explanatory diagram of the method of casting in this embodiment, and Figure 3 is an explanatory diagram of the light emitting state of the LED in that embodiment. ,
Fig. 4 is a circuit diagram of the embodiment, Figs. 5 to 8 are explanatory diagrams of the control of the embodiment, Fig. 9 is a sectional view showing the schematic structure of the copying machine, and Fig. 10 is a conventional blank lamp. FIG. 11 is a perspective view of an example, and FIG. 11 is an explanatory diagram showing a conventional example with a part thereof cut away together with a photoreceptor. FIGS. 12 to 14 are explanatory diagrams of control of the conventional example.

a, b...LED row, 1a-20a...L E
LED in D row a, lb~20...LED in LED row
, 30... Blank lamp, 31... Housing,
32... Partition plate, 40.50... Exposure area, 11
0...Photoreceptor.

Figure 1 Figure 3 Figure 5 Figure 7 Figure 8 Figure 10 Ballot 11

Claims (1)

[Scope of Claims] 1. Blank lamps provided opposite to the photoreceptor of an electrophotographic copying machine, which are arranged in parallel and extending in a direction substantially perpendicular to the direction of movement of the photoreceptor. A first light emitting element row and a second light emitting element row, a first light shielding section provided around and between both of the light emitting element rows, and a first light shielding section provided between each light emitting element in the light emitting element row. and a control means for controlling the light emission of each light emitting element, and the tip of the first light shielding part and the tip of the second light shielding part correspond to each light emitting element. an opening facing the body is formed, and the difference between the distance between the photoreceptor and the tip of the second light shielding part and the distance between the photoreceptor and the light emitting elements in the first light emitting element row. is the distance between the photoreceptor and the second light shielding part, and the distance between the photoreceptor and the second light shielding part.
A blank lamp for an electrophotographic copying machine that is smaller than the difference in distance between light emitting elements in a row of light emitting elements. 2. The blank lamp according to claim 1, wherein a tip of the first light shielding portion protrudes more toward the photoreceptor than a tip of the second light shielding portion. 3. The blank lamp according to claim 1 or 2, wherein the first light emitting element row is provided upstream of the second light emitting element row in the movement direction of the photoreceptor. . 4. The blank lamp according to claim 1 or 2, wherein the second light emitting element row is provided upstream of the first light emitting element row in the movement direction of the photoreceptor. .