JPH0317313Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a specific area static elimination mechanism in a so-called center reference type copying machine in which the center of the width of a document is aligned with the center of the width of a contact glass. A large number of static eliminating lamps are spaced apart in the direction of the drum axis so that they can emit light over the entire width of the image area of the photosensitive drum, and a partition plate is provided for each static eliminating lamp to define the light emitting area of each static eliminating lamp. The present invention relates to a specific area static elimination mechanism for a center reference copying machine, which is provided between lamps and eliminates the potential in a specific area on the surface of a photosensitive drum by controlling the blinking of the static elimination lamp.

(Prior Art) Conventionally, in order to control the charged area on a photoreceptor formed by a charging device, it has been known to remove unnecessary charges using light irradiation from a static elimination lamp.

Conventionally, a plurality of static elimination lamps are arranged in a straight line, and the static elimination lamps are installed in a static elimination lamp housing whose light irradiation area is regulated by a partition plate to constitute a static elimination mechanism, and this is connected to the main body of the copying machine. It was fixedly installed.

(Problem to be solved by the invention) However, in the above-mentioned conventional static elimination mechanism, there is a limit to miniaturization due to the structure of the lamp alone, and it is difficult to make the static elimination lamp blink in response to changing the magnification. Another drawback is that it is not possible to identify the area where a latent image is formed on the photoreceptor by blinking a static elimination lamp corresponding to a specific area of the document regardless of the magnification.

The present invention was devised in view of the above-mentioned circumstances, and aims to eliminate the above-mentioned drawbacks through simple improvements.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a specific area static elimination mechanism of the center-based copying machine described at the beginning, in which the width of copying paper of the minimum size that can be copied in the center-based copying machine is An integer number of static elimination lamps corresponding to
Subtracting the number of fixed charge eliminating lamps from the required total number of charge eliminating lamps, dividing the number into two, and adding at least one charge eliminating lamp each to the first and second charge eliminating lamp groups, are connected to the fixed charge eliminating lamps in the direction of the axis of the drum. The partition plate is provided on both sides of the drum and is movable in the drum axis direction by at least one pitch of the arrangement pitch of the partition plate, with the light projection area partially overlapping.

(Function) According to the characteristic structure described above, by changing the positions of the first and second static elimination lamp groups, the boundary between the charged area and the static neutralization area on the drum surface can be changed and set steplessly. .

(Embodiment) Hereinafter, an embodiment of the present invention will be explained based on the drawings. Fig. 3 shows the entire copying machine of the so-called center reference type, and in the figure, 1 has a contact glass 2 and a document holder 3 on the top. The copier itself is equipped with
An exposure device 5 with a movable optical system is disposed in an upper space partitioned by the partition plate 4 .

The exposure device 5 is composed of a light source 6, first to fourth reflecting plates 7 to 10, and a condensing lens 11, and the condensing lens 11 is able to change its position steplessly in the optical path direction. Exposure can be performed using a zoom mechanism for magnification and reduction.

Next, 12 in the figure is a photosensitive drum, which includes a charging device 13, a specific area static elimination mechanism 14, and a developing device 1.
5. A transfer device 16, a copy paper separation device 17, and a cleaning device 18 are arranged in this order in the drum rotation direction R.

Reference numeral 19 designates a loading section of the cassette case 20, 21 a paper feed conveyance device, 22 a paper discharge conveyance device, 23 a heat fixing device, 24 a pair of paper discharge rollers, and 25 a tray.

Next, a specific example of the specific area static elimination mechanism 14 will be explained based on FIG. 1 and FIG. Therefore, a large number of static elimination lamps a, b, and c capable of eliminating the potential on the surface of the drum over the entire width in the axial direction of the drum,
It consists of a partition plate d for defining the light projection area of each of the static elimination lamps a, b, and c.

Specifically, the static elimination lamps a and b are separated by a predetermined interval in the direction of the drum axis, and have an upper limit of the width of the smallest copy paper that can be copied in the center reference copying machine, and a narrower range than that. An integer number (four is exemplified) of static elimination lamps a capable of projecting light onto the image area l of the photosensitive drum 12 are fixedly provided in a distributed manner with reference to the center in the axial direction of the photosensitive drum 12; The fixed static electricity removal lamp a
A partition plate d is fixedly provided for defining the light projection area for each of the areas.

Then, subtracting the number of stationary static eliminating lamps a from the total number of static eliminating lamps a and b required to neutralize the entire width of the image area of the photosensitive drum 12,
The number of static electricity removal lamps a
The number of items shall be changed as appropriate. ) is divided into two halves, and one static elimination lamp c is added to each half.
and a second static elimination lamp group A, B on both sides of the fixed static elimination lamp group (including the case where there is one static elimination lamp a) C in the drum axis direction, and
It is movable in the drum axis direction by one pitch of the arrangement pitch of the partition plate d, with the light projection area partially overlapping.

Regarding the cantering mechanism of the first and second static elimination lamp groups A and B, this one has racks e and e arranged in series on the fixed static elimination lamp group C side of the lamp groups A and B, and the racks e and A pinion f that meshes with the rack g is pivotally mounted on the side of the copying machine main body 1, and a rack g is connected to the other end of the first static elimination lamp group A, and a pinion h that meshes with the rack g is mounted. It is provided in the stepping motor M.

This motor M moves both static eliminator lamp groups A and B in a direction to approach each other within one pitch of the arrangement pitch of the partition plate d, based on the input of the copy width control signal, and It is configured to automatically return to the initial position in response to a signal when the copying operation is completed (for example, a signal when the heater of the heat fixing device 23 is switched to the power saving mode).

Note that S in the figure is a sensor for detecting the initial position.

According to the above configuration, there is a charging mode in which all of the static elimination lamps a, b, and c are turned off, and only the same number of lamps b that are appropriately consecutive from the outside of the first and second static elimination lamp groups A and B are used. By appropriately selecting and setting the mode of partial charging including the central portion of the drum that lights up, a partial copying method that charges a further range of the drum center evenly distributed area including the range of the fixed static neutralizing lamp a. Furthermore, when making a partial copy, the boundary T between _{the lit static elimination lamp b 1 marked} with a circle in FIG. By moving the lamp groups A and B by changing their positions in the drum axis direction, it is possible to arbitrarily set the width of the partial copy evenly distributed at the drum center, including the drum center portion.

Alternatively, partial white copying can be performed by controlling the lighting and extinguishing of the static eliminating lamp b and the fixed static eliminating lamp a to be reversed.

The width control in the direction of movement of the optical system for partial copying and whiteout copying described above is performed by controlling the lighting of all the required numbers of lamps a and b, as in the prior art.

FIG. 4 shows another embodiment of the specific area static elimination mechanism 14. This one includes the first and second static elimination lamp groups A,
A rack g is provided on each of the stepping motors B, and a pinion h that meshes with the rack g is provided on each independently controlled stepping motor M.
Although a stand is required, partial copying of any width including the range of the fixed static eliminating lamp group C or partial white copying is possible.

(Effect of the invention) As explained above, according to the specific area static elimination mechanism of the present invention, by moving the first and second static elimination lamp groups in the direction of the drum axis, the static elimination area and the charged area on the drum surface can be separated. The boundaries of the lamp can be changed steplessly without being limited by the size of the lamp itself, and it is possible to change the size, make partial copies, or outline copies, including the width of the fixed static electricity removal lamp. Only the effective image area at the time can be developed,
As a result, it has become possible to eliminate wasteful toner consumption and unnecessary transfer of black streaks.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a specific area static elimination mechanism, FIG. 2 is an explanatory diagram of partial copying, FIG. 3 is a schematic sectional view of the entire copying machine, and FIG. 4 is a configuration diagram of another embodiment. a, b, c... Static elimination lamp, d... Partition plate, A
...First static elimination lamp group, B...Second static elimination lamp group.

Claims (1)

[Scope of utility model registration request] A large number of static eliminator lamps are installed at intervals in the drum axis direction so as to be able to emit light over the entire width of the image area of the photosensitive drum, and a partition plate is provided for each static eliminator to define the light emitting area of each static eliminator lamp. A specific area static elimination mechanism for a center reference copying machine, which is provided between lamps and reduces the potential in a specific area on the surface of a photosensitive drum by blinking control of the static elimination lamp, the mechanism for eliminating electricity in a specific area of the center reference copying machine. An integer number of static eliminating lamps corresponding to the smallest possible copy paper width is fixedly provided as the upper limit of the number of static eliminating lamps, and the number of fixed static eliminating lamps is subtracted from the total number of required static eliminating lamps to divide it into two, and at least each of the fixed static eliminating lamps is divided into two. The partition plate is arranged such that the first and second static elimination lamp groups including one static elimination lamp are placed on both sides of the fixed static elimination lamp in the direction of the axis of the drum, and the light emitting areas can partially overlap. A specific area neutralization mechanism for a center reference copying machine, characterized in that it is provided movably in the direction of a drum axis by at least one pitch.