KR20080053722A - Image forming apparatus discriminating paper type and method thereof - Google Patents

Abstract

An image forming apparatus for discriminating a paper type and its method are provided to improve printing quality by outputting a proper transfer voltage for each discriminated paper type according to a pattern of a light receiving amount. A light emitting unit(110) emits light to paper. A reflective light receiving unit(120) receives reflective light reflected from the paper. A transmissive light receiving unit(130) receives transmissive light that transmits through the paper. A storage unit(140) stores patterns of light receiving amounts by papers. A determining unit(150) searches a pattern matched to a pattern formed by the respective light receiving amounts of the reflective light receiving unit and the transmissive light receiving unit from the storage unit, and detects a type of paper.

Description

Image forming apparatus discriminating paper type and method

1 is a block diagram showing the configuration of an image forming apparatus according to an embodiment of the present invention;

FIG. 2 is a block diagram showing in detail the configuration of the image forming apparatus of FIG. 1; FIG.

3 is a schematic view for explaining the arrangement of the reflected light receiver and the projection light receiver of FIG.

4 is a schematic diagram for explaining a light receiving amount pattern according to an embodiment of the present invention, and

5 is a flowchart illustrating a paper type discrimination method according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: image forming apparatus 110: light emitting unit

120: reflected light receiving unit 130: projection light receiving unit

140: storage unit 150: determination unit

The present invention relates to an image forming apparatus for discriminating paper types and a method thereof, and more particularly, to an image forming apparatus for discriminating paper types by using a light receiving amount pattern formed according to reflected light reflected from a paper and projected light. It's about how.

In general, the image forming apparatus charges the surface of the photosensitive medium by using a charging device and exposes the photosensitive medium by light irradiated from the laser scanning unit according to a print signal to form an electrostatic latent image, and then the toner supplied from the developing apparatus. Is a device for forming a toner image by transferring the film to a sheet to obtain an image. Such an image forming apparatus employs a contact charging method in which a charging device contacts a photosensitive medium to form a predetermined potential on the surface of the photosensitive medium.

On the other hand, in order for the toner image formed on the photosensitive medium to be transferred onto the paper, an appropriate transfer voltage is applied to the transfer roller according to the paper type to form a good image. Therefore, there is a need for a technique capable of discriminating paper types. The same applies to the inkjet image forming apparatus.

In the conventional paper type discrimination method, when the front end of the paper passes the transfer roller, the paper type is discriminated by measuring the resistance value of the transfer roller. Specifically, conventionally, it detects its own resistance when the paper does not pass between the photosensitive medium and the transfer roller, and applies a high voltage when the paper leading passes between the photosensitive medium and the transfer roller, so that the paper, the photosensitive medium, and the transfer roller are separated. The synthetic resistance was detected, and the method of discriminating the paper type by adding the detected synthetic resistance and the self resistance was used.

However, according to the conventional paper discrimination method, the actual measured self-resistance and the combined resistance are measured from several mega ohms (MΩ) to several tens of mega ohms (MΩ), and each sheet is measured using a resistance measured in a wide range. There is a problem that the accuracy is poor in determining the type or the appropriate transfer voltage to be applied according to each paper type.

In addition, in papers of poor paper quality, such as recycled paper, there is a problem in that the pulp arrangement of the paper is not constant, so that the resistance value measured on the paper is not constant. Therefore, it is difficult to accurately determine the paper type using the resistance value. There was a difficult problem.

SUMMARY OF THE INVENTION The present invention has been proposed to achieve the above object, and an object of the present invention is an image forming apparatus capable of accurately discriminating paper types by using a light receiving amount pattern formed according to reflected light reflected from a paper and projected light. And it provides a method.

An image forming apparatus according to an embodiment of the present invention for achieving the above object is a light emitting unit for irradiating light to the paper, a reflected light receiving unit for receiving the reflected light reflected from the paper, projection for receiving the projection light passing through the paper A light receiving unit, a storage unit storing a light receiving amount pattern for each paper, and a pattern matching unit that matches the pattern formed by the light receiving amount of each of the reflected light receiving unit and the projection light receiving unit is searched in the storage unit to detect the paper type Include.

In this case, the reflected light receiving unit includes a first reflected light receiving unit disposed on one side of the light emitting unit and a second reflected light receiving unit disposed on the other side of the light emitting unit, and the projection light receiving unit is configured to emit the light through the paper. And a first projection light receiving unit disposed at a position facing the unit, a second projection light receiving unit disposed at one side of the first projection light receiving unit, and a third projection light receiving unit disposed at the other side of the first projection light receiving unit. Can be.

More preferably, the transfer roller drive unit for performing a transfer operation by supplying a transfer voltage to the transfer roller, and controlling the transfer roller drive unit to supply a transfer voltage of a size corresponding to the paper type detected by the determination unit The control unit may further include.

On the other hand, the paper discrimination method of the image forming apparatus according to another embodiment of the present invention by irradiating light to the paper, receiving the reflected light reflected from the paper and the projection light passing through the paper, and the paper type distinction And searching for a pattern matching the pattern formed by the received light amount of the reflected light and the projected light from the stored light amount pattern, and discriminating the type of the paper.

In this case, the receiving of the reflected light and the projection light may include: a first light receiving element disposed on one side of the light emitting element for irradiating the light, a second light receiving element disposed on the other side of the light emitting element, and the paper; Light receiving using a third light receiving element disposed at a position facing the light emitting element, a fourth light receiving element disposed at one side of the third light receiving element, and a fifth light receiving element disposed at the other side of the third light receiving element can do.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention.

1 is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. According to FIG. 1, the image forming apparatus 100 includes a light emitter 110, a reflected light receiver 120, a projection light receiver 130, a storage 140, and a determiner 150.

The light emitting unit 110 is irradiated with light to the paper picked up from the paper cassette (not shown) and conveyed by the feed roller (not shown). In this case, any light source that can transmit paper such as an LED or a laser diode may be applied.

Meanwhile, the light irradiated from the light emitting unit 110 may be reflected or projected from the paper according to the type of the paper.

Here, the paper type may be ink-jet paper, OHP paper, general paper according to the thickness of the paper, recycled paper, etc., and the light irradiated from the light emitting unit 110 may be reflected or reflected depending on the characteristics of the material and thickness of each paper. Projected.

The reflected light receiving unit 120 receives the reflected light from which the light emitted from the light emitting unit 110 is reflected from the paper.

The projection light receiving unit 130 receives the projection light through which the light emitted from the light emitting unit 110 passes through the paper.

The storage unit 140 stores a light receiving amount pattern for each sheet. Here, the light receiving amount pattern is a specific pattern formed according to characteristics such as the material and thickness of the paper.

The determination unit 150 detects a paper type by searching for a pattern in the storage unit 140 that matches a pattern formed by the received light amount of each of the reflected light receiver 120 and the projected light receiver 130.

FIG. 2 is a block diagram specifically illustrating a configuration of the image forming apparatus of FIG. 1. According to FIG. 2, the image forming apparatus 100 may further include a transfer roller driver 160 and a controller 170 in the configuration of FIG. 1.

When the print command is received, the control unit 170 picks up the paper from the paper cassette (not shown) and controls the light emitting unit 110 to irradiate light onto the paper to be picked up and transported. On the other hand, the reflected light receiving unit 120 and the projection light receiving unit 130 for receiving the irradiated light may be implemented in plurality.

The determination unit 150 detects a pattern formed from the arrangement positions of the plurality of reflected light receivers 121 and 122 and the projection light receivers 131, 132, and 133, and the amount of received light. Here, the arrangement of the reflection light receiving units 121 and 122 and the projection light receiving units 131, 132, and 133 may be described with reference to FIG. 3.

FIG. 3 is a schematic diagram for explaining the arrangement of the reflected light receiver and the projection light receiver of FIG. 2. Referring to FIG. 3, the reflected light receiver 120 is implemented by the first reflected light receiver 121 disposed on one side of the light emitter 110 and the second reflected light receiver 122 disposed on the other side of the light emitter 110. Can be.

In addition, the projection light receiving unit 130 includes a first projection light receiving unit 131 disposed at a position facing the light emitting unit 110 with the paper 10 therebetween, and a second disposed at one side of the first projection light receiving unit. The projection light receiving unit 132 and the third projection light receiving unit 133 disposed on the other side of the first projection light receiving unit may be implemented.

At this time, as the interval between the plurality of reflected light receiving units 121 and 122 and the distance between the projection light receiving units 131, 132, and 133 are narrower, the determination unit 150 is configured to reflect the reflected light receiving unit 120 and the projection. The pattern formed by each of the light receiving units 130 may be accurately determined.

Meanwhile, the light emitting unit 110 is implemented as a light emitting element, and the reflected light receiving units 121 and 122, and the projection light receiving units 131, 132, and 133 are the first to fifth light receiving elements A, B, C, and D, respectively. , E).

The storage unit 140 stores the light receiving amount pattern according to the characteristics of each sheet, and stores the pattern considering the arrangement positions of the reflected light receiving units 121 and 122 and the projection light receiving units 131, 132, and 133.

The determination unit 150 detects a paper type by detecting a matching pattern among the patterns formed from the light receiving units 121, 122, 131, 132, and 133 and the light receiving amount patterns stored in the storage unit 140. Here, the light-receiving amount pattern for each sheet may be described with reference to FIG. 4.

4 is a schematic diagram illustrating a light receiving amount pattern according to an embodiment of the present invention. According to FIG. 4, the vertical axis represents the light reception amount of the light receiving units 121, 122, 131, 132, and 133, and the horizontal axis represents the paper type. Here, the light receiving amount pattern is a pattern considering the arrangement of the reflected light receiving parts 121 and 122 and the projection light receiving parts 131, 132, and 133.

Here, A to E are the first reflected light receiving unit 121, the second reflected light receiving unit 122, the second projection light receiving unit 132, the first projection light receiving unit 131, and the third projection light receiving unit 133, respectively. It means the amount of received light.

On the other hand, in the case of inkjet paper, the coding liquid is coated on the surface, so the light reflectance is very high and the light transmittance is low. In the case of OHP paper, the light transmittance is very high. In the case of plain paper, the heavier the g, the thicker the paper, the higher the reflectance and the lower the transmittance.

On the other hand, in the case of paper such as recycled paper, the thickness of the paper is so thin that the light transmittance is very high. According to the characteristics of each sheet, the light receiving amount patterns shown in FIG. 4 are formed.

On the other hand, even if the paper type is the same type, a pattern error occurs depending on the manufacturer. Therefore, the determination unit 150 detects the paper type by recognizing the same pattern when the stored pattern for each paper and the received light amount pattern formed by the emission light receiving unit 120 and the projection light receiving unit 130 match within a certain error range. do.

The transfer roller driver 160 supplies a transfer voltage to the transfer roller to perform a transfer operation.

The controller 170 controls the transfer roller driver 160 to supply a transfer voltage having a size corresponding to the type of paper detected by the determiner 150.

Accordingly, the transfer cassette can be supplied with the paper cassette (not shown) by determining the type of the paper not classified by type.

5 is a flowchart illustrating a paper type discrimination method according to an embodiment of the present invention. According to FIG. 5, light is irradiated onto the paper (S510), and the reflected light reflected from the paper and the projection light passing through the paper are received (S520).

Here, the received light of the reflected light and the projection light is the first light receiving element disposed on one side of the light emitting element for irradiating the light, the second light receiving element disposed on the other side of the light emitting element, the position facing the light emitting element across the paper The light-receiving device is received using a third light receiving element disposed in the second light receiving element, a fourth light receiving element disposed on one side of the third light receiving element, and a fifth light receiving element disposed on the other side of the third light receiving element.

Next, a pattern matching the pattern formed by the received light amount of the reflected light and the projected light is searched from the received light amount pattern stored for each paper type (S530) to discriminate the type of paper (S540). That is, the paper type can be discriminated by a specific pattern formed according to the arrangement position and the light receiving amount of the first to fifth light receiving elements.

As described above, according to the present invention, it is possible to accurately discriminate the type of paper by using the light receiving amount pattern formed according to the reflected light reflected from the paper and the projected light to be projected. Accordingly, an appropriate transfer voltage can be output for each type of paper discriminated according to the light receiving amount pattern, thereby improving print quality.

Although the above has been illustrated and described with respect to the preferred embodiments of the present invention, the present invention is not limited to the above-described specific embodiments, it is usually in the art without departing from the spirit of the invention claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

Claims (5)

In the image forming apparatus, A light emitting unit for irradiating light onto the paper; A reflected light receiving unit for receiving reflected light reflected from the paper; A projection light receiving unit that receives projection light passing through the paper; A storage unit for storing a light receiving amount pattern for each paper; And, And a determination unit which detects the paper type by searching the storage unit for a pattern matching a pattern formed by the reflected light receiving unit and the projection light receiving unit, respectively. The method of claim 1, The reflected light receiving unit, A first reflected light receiving unit disposed on one side of the light emitting unit and a second reflected light receiving unit disposed on the other side of the light emitting unit; The projection light receiving unit includes a first projection light receiving unit disposed at a position facing the light emitting unit with the paper interposed therebetween, a second projection light receiving unit disposed at one side of the first projection light receiving unit, and the first projection light And a third projection light receiving unit disposed on the other side of the light receiving unit. The method according to claim 1 or 2, A transfer roller driver for supplying a transfer voltage to the transfer roller to perform a transfer operation; And, And a controller configured to control the transfer roller driver to supply a transfer voltage having a size corresponding to the paper type detected by the determination unit. In the paper discrimination method of the image forming apparatus, Irradiating light onto a paper to receive reflected light reflected from the paper and projection light passing through the paper; And, And searching for a pattern matching a pattern formed by the received light amount of the reflected light and the projected light from the received light amount pattern for each paper type, and discriminating the type of the paper. The method of claim 4, wherein Receiving the reflected light and the projection light, A first light receiving element disposed on one side of the light emitting element for irradiating the light, a second light receiving element disposed on the other side of the light emitting element, and a third disposed at a position facing the light emitting element with the paper interposed therebetween And receiving the light using a light receiving element, a fourth light receiving element disposed on one side of the third light receiving element, and a fifth light receiving element disposed on the other side of the third light receiving element.

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