KR20040024016A - Image forming device and driving method thereof - Google Patents

Abstract

PURPOSE: An image forming apparatus and a driving method therefor are provided to calculate a partial transfer speed of a recording paper, and to predict transfer time for the recording paper arriving at a transfer roller by using the calculated partial transfer speed, thereby controlling an optical scanning point of an optical scanning device. CONSTITUTION: A pickup roller(164) picks up a recording paper(P) received in a cassette(162) when a driving command is received. The first document position sensor(180) is installed on a set paper transfer path(170), and detects whether the recording paper(P) arrives at the first detection position set by the pickup roller(164). The second document position sensor(182) is disposed on the paper transfer path(170) between the first document position sensor(180) and a transfer roller(195), and detects whether the recording paper(P) arrives at the second detection position. A controller(130) calculates a transfer speed of the recording paper(P) by using partial transfer time information up to a point when a front end of the recording paper(P) passing through the first sensor(180) passes through the second sensor(182) from a point when the front end passes through the first sensor(180). The controller(130) predicts transfer time for the recording paper(P) arriving at the transfer roller(195), and determines an optical scanning point of an optical scanning device(193).

Description

Image forming device and driving method

The present invention relates to an image forming apparatus and a driving method thereof, and more particularly, to an image forming apparatus capable of uniformly outputting a leading margin of a recording sheet by determining an optical scanning time point of the optical scanning apparatus according to a transfer condition of the recording sheet. An apparatus and a driving method thereof are provided.

In general, an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction apparatus that implements a combination of these functions through a single device has a common printing function.

Such an image forming apparatus includes an inkjet method and a laser printing method according to a printing method of a printing engine. Recently, an image printing apparatus using a laser printing method having a high printing speed has been widely used.

1 is a schematic cross-sectional view of an image forming apparatus to which a conventional laser printing method is applied.

Referring to the drawings, the image forming apparatus includes a paper conveying unit, a paper position detecting sensor 30, and a printing unit 50.

The paper conveying unit comprises a cassette 12, a pickup roller 14 for picking up the recording paper P loaded in the cassette 12, and at least one conveying the recording paper P along the set paper conveying path 20. The above feed roller 16 is provided.

The paper position detection sensor 30 detects whether the recording paper P has reached the set reference position.

The printing unit 50 prints an image on the recording paper P supplied.

The printing unit 50 applies a developer to the electrostatic latent image formed by the photosensitive medium 52, the optical scanning device 54 for scanning light onto the photosensitive medium 52, and the optical scanning device 54 on the photosensitive medium 52. And a developing roller 56 for supplying and developing the transfer roller 58 for transferring the image developed by the developing unit 56 to the recording paper P to be supplied.

In the operation of the image forming apparatus having the above-described configuration, when a print command is input from the user, the recording paper P accommodated in the cassette 12 is picked up by the pickup roller 14, and the paper conveying path 20 Move along The paper position detection sensor 30 detects whether or not the recording paper P has reached the set reference position.

A control unit (not shown) for controlling the overall operation of the image forming apparatus determines the optical scanning timing of the optical scanning device 54 according to the detection result signal of the paper position detection sensor 30. At this time, the paper feed speed and the paper position detection sensor until the recording paper P conveyed by the feed roller 16 reaches the set reference position and the paper position detection sensor 30 outputs the leading detection result signal. When the paper feed speed from the 30 to the transfer roller 58 is constant, the leading margin of the recording paper P can always be kept constant.

However, depending on the material or thickness of the recording paper P, the time required for the recording paper P picked up by the pick-up roller 14 to be detected by the paper position detecting sensor 30 and the recording paper P are changed. The time taken to reach the transfer roller 58 may vary. As a result, in the conventional image forming apparatus, a deviation occurs between the optical scanning time of the optical scanning device 54 and the paper feed speed, thereby causing a problem that the leading margin of the recording paper P is not constant.

The technical problem to be achieved by the present invention is an image forming apparatus capable of compensating the tip margin of a recording paper by appropriately adjusting the optical scanning timing of the optical scanning device in consideration of the change in the feed speed of the recording paper according to the characteristics of the various recording papers and its It is to provide a driving method.

1 is a schematic cross-sectional view of a conventional image forming apparatus;

2 is a block diagram of an image forming apparatus according to a preferred embodiment of the present invention;

3 is a schematic cross-sectional view of the printing engine shown in FIG.

4 is a flowchart illustrating a method of driving an image forming apparatus according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: image forming apparatus 110: OPE unit

120: interface unit 130: control unit

140: storage unit 150: printing engine unit

180: first detection sensor 182: second detection sensor

In order to achieve the above technical problem, a photosensitive medium, a light scanning device for scanning light to the photosensitive medium, and a developing device for supplying and developing a developer to the electrostatic latent image formed by the light scanning device to the photosensitive medium; An image forming apparatus having a transfer roller for transferring an image developed by the developing device to a photosensitive medium on a sheet to be fed, a pickup roller for picking up a recording paper stored in a cassette upon receiving a driving command, and a predetermined roller on a predetermined paper transfer path. A first detection sensor which detects whether the recording paper has reached the first detection position set and set at the position, the second detection position disposed on the paper transfer path between the first detection sensor and the transfer roller, The second detection sensor for detecting whether the recording paper has arrived and the point at which the leading end of the recording paper passes through the first detection sensor; The transfer speed of the recording paper is calculated using the partial transfer time information until the tip of the recording paper passing through the first sensing sensor passes the second sensing sensor, and the recording is performed based on the calculated transfer speed. And a control unit for predicting a transfer time required for the paper to reach the transfer roller to determine an optical scanning time point of the optical scanning device.

In order to achieve the above another technical problem, a photosensitive medium, a light scanning device for scanning light to the photosensitive medium, and a developing device for developing by supplying a developer to the electrostatic latent image formed by the light scanning device to the photosensitive medium; A transfer roller which transfers the image developed by the developing machine to the photosensitive medium, and a pickup roller, a pickup roller, and a position spaced apart from the pickup roller by a predetermined distance, the recording paper at a set first detection position. A first detection sensor for detecting whether the paper sheet has been reached, and a second detection sensor for detecting whether the recording sheet has reached the set second detection position disposed on the paper feed path between the first detection sensor and the transfer roller. In the driving method of the image forming apparatus having a second sensing sensor from the first sensing sensor by using the output signal of the first sensing sensor and the second sensing sensor. Calculating a conveying speed of the recording paper used to transport the recording paper to a sensing sensor; and based on the calculated conveying speed, the recording paper is required to reach the transfer roller from the second sensing sensor. Estimating a light scanning time point of the optical scanning device by predicting a transfer time.

Hereinafter, with reference to the drawings will be described an embodiment of the present invention;

2 is a block diagram of an image forming apparatus according to a preferred embodiment of the present invention.

Referring to the drawings, the image forming apparatus 100 includes an operating panel (OPE) 110, an interface unit 120, a controller 130, a storage 140, and a print engine 150. do.

The interface unit 120 supports mutual data communication between a computer, which is an external device, and the controller 130 through the communication interface 122. For example, a universal serial bus (USB) module capable of a bidirectional serial interface or an ECP module capable of a bidirectional parallel interface may be applied. Accordingly, the interface unit 120 may receive print data from a computer, and may provide print information corresponding to a power supply state of the image forming apparatus 100, print start / end, and the like to the computer.

The OPE unit 110 includes an input unit 112 and a display unit 114.

The input unit 112 is provided with a plurality of function keys for setting various functions supported by the image forming apparatus 100.

The display unit 114 displays an operation state of the image forming apparatus 100 under the control of the controller 130 to be described later.

The storage 140 stores information on data and data generated during an operation of the image forming apparatus 100 and an inactive memory such as a ROM in which various control programs necessary for implementing the functions of the image forming apparatus 100 are stored. It is made of volatile memory such as DRAM to store.

In addition, the storage 140 stores partial transfer time information from a time point at which the recording paper passes through the first sensing sensor installed at a predetermined position on the paper conveying path to a time point passing through the second sensing sensor.

The print engine 150 performs a print job on the print target data under the control of the controller 130. The print engine 150 includes first and second detection sensors for detecting a set paper position, a paper feeder, a light scanning device, a photosensitive medium, a transfer roller, a charger, a developing machine, and a fixing machine.

3 is a schematic cross-sectional view of the printing engine shown in FIG. 2.

Referring to the drawings, the print engine 150 includes a paper feeder, a first sensor 180, a second sensor 182, and a printer 190.

The paper feeder transfers the cassette 162 and the pickup paper 164 picking up the recording paper P loaded in the cassette 162 and the recording paper P taken out by the pickup roller 164 to the transfer roller 195. At least one conveying roller 166 for conveying along the sheet conveying path 170 is provided.

The first detection sensor 180 is installed at a predetermined position on the paper feed path 170, and the recording paper P picked up by the pickup roller 164 is transferred along the paper feed path 170 to set the first detection. A sensor for detecting whether a position has been reached (Document Position Sensor).

The second detection sensor 182 is disposed at a predetermined position on the paper transfer path 170 between the first detection sensor 180 and the transfer roller 195 to determine whether the recording paper P has reached the set second detection position. It is a sensor for detecting whether or not (Document Position Sensor).

The printing unit 190 includes a photosensitive drum 191, a charger 192, a light scanning device 193, a developing device 194, a transfer roller 195, and a fixing unit 196.

The charger 192 uniformly charges the electric charge layer on the surface of the photosensitive drum 191 applied to the photosensitive medium while the charging roller 192a is rotated by a high voltage applied from a high voltage power supply unit (not shown).

The optical scanning device 193 is controlled by the control unit 130 to scan the light to the photosensitive drum 191 to correspond to the print data at an appropriate time.

The developing unit 194 develops the electrostatic latent image formed on the photosensitive drum 191 by the optical scanning device 193 with a developer having a charge while the developing roller 194a is rotated by the developing device voltage applied from the high voltage power supply unit.

The transfer roller 195 rotates in engagement with the photosensitive drum 191 and prints the image processed on the photosensitive drum 191 on the recording paper P to be inserted.

In the fixing unit 196, an image printed on the recording sheet P by the transfer roller 195 is fixed to the recording sheet P. FIG. The recording paper P fixed by the fixing unit 196 is discharged to the outside along the paper discharge direction by a discharge roller (not shown) to complete the image forming process.

The controller 130 controls each unit, determines a driving time point for each element of the print engine unit 150, and controls the respective parts according to the determined driving time point so that a print job for the print data may be performed. Control 150.

An element to determine the driving timing of the print engine 150 is, for example, the optical scanning timing of the optical scanning device 193. The controller 130 is a determinant for determining the optical scanning time of the optical scanning device 193, and the detection result signals of the first and second detection sensors 180 and 182, and the first and second detection sensors 180. 182, the distance information of the paper feed path 170 from the second detection sensor 182 to the transfer roller 195 is used.

When a detection result signal indicating that the recording paper P has reached the first and second detection positions set from the first and second detection sensors 180 and 182 is received, the controller 130 controls the recording paper P. Recorded by using the partial transfer time information from the time when the tip passes the first detection sensor 180 to the time passing the second detection sensor and the arrangement interval information of the first and second detection sensors 180 and 182. The partial feed speed of the paper P is calculated.

The control unit 130 uses the calculated partial feed speed and distance information of the paper feed path 170 from the second sensing sensor 182 to the transfer roller 195 to transfer the recording paper P to the transfer roller 195. You can estimate the transfer time to reach. Therefore, the controller 130 may determine the time of light scanning on the photosensitive drum 191 by appropriately timing the recording paper P to enter the transfer roller 195.

That is, the controller 130 may adjust an appropriate driving time point for each element of the print engine 150 in consideration of the change in the feed speed according to the characteristics of the recording paper P. FIG.

Hereinafter, a driving method of an image forming apparatus according to an exemplary embodiment of the present invention will be described with reference to FIG. 4.

When a print command signal is received from a computer that is an external device (S200), a drive command signal is received from the controller 130, and the pickup roller 164 picks up the recording paper P loaded in the cassette 162 (S210). .

When the recording paper P picked up by the pickup roller 164 is transferred along the paper feed path 170 set by the feeding roller 166 to reach the set detection position, the first detection sensor 180 records the recording paper. Detecting the front end of (P) and outputs the front end detection result signal to the controller (130).

When the front end detection result signal of the recording paper P is received from the first sensing sensor 180 (S220), the controller 130 stores the front end detection time information of the first sensing sensor 180 in the storage 140. do. In addition, when the front end detection result signal of the recording paper P is received from the second detection sensor 182 (S230), the control unit 130 stores the tip detection time information of the second detection sensor 182. Store in

The control unit 130 uses the tip detection time information of the first detection sensor 180 and the second detection sensor 182 to record the recording paper P from the first detection sensor 180 to the second detection sensor 182. Calculate the partial feed rate of (S240).

The controller 130 estimates the transfer time required to reach the transfer roller 195 by using the partial feed speed calculated in step S240 and the distance information from the second detection sensor 182 to the transfer roller 195. The optical scanning point of the optical scanning device 193 is determined (S250).

The print engine 150 performs a print job on the print data under the control of the controller 130 (S260).

As described above, the first and second detection sensors 180 and 182 capable of detecting whether or not the recording paper P has reached the set first and second detection positions are provided. Since the partial feed rate is calculated and the transfer time required for the recording paper P to reach the transfer roller 195 can be estimated using the calculated partial feed rate, the optical scanning of the optical scanning device 193 is performed. The viewpoint can be adjusted.

As described above, according to the image forming apparatus and the driving method thereof, the driving time of the print engine can be adjusted in consideration of the change in the feed speed of the recording paper according to the characteristics of the recording paper, so that the leading margin of the recording paper is increased. It is possible to improve print quality because it remains constant regardless of paper.

Although the present invention has been described in detail through the representative embodiments, those skilled in the art to which the present invention pertains can make various modifications without departing from the scope of the present invention. Will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

Claims (2)

A photosensitive medium, a light scanning device for scanning light onto the photosensitive medium, a developing device for supplying and developing a developer on an electrostatic latent image formed by the light scanning device on the photosensitive medium, and a developing device by the developing device on the photosensitive medium. An image forming apparatus comprising: a transfer roller for transferring a transferred image onto a sheet of paper to be supplied; A pickup roller which picks up the recording paper stored in the cassette when the driving command is received; A first sensing sensor installed at a predetermined position on a set paper conveying path and detecting whether the recording paper has reached the set first detection position picked up by the pickup roller; A second detection sensor detecting whether the recording paper has reached a second detection position set on the paper transfer path between the first detection sensor and the transfer roller; And The recording paper using the partial transfer time information from the time when the front end of the recording paper passes through the first sensing sensor to the time when the front end of the recording paper passing through the first sensing sensor passes through the second sensing sensor. And a control unit for calculating an optical scanning time of the optical scanning device by calculating a conveying speed of the and predicting a conveying time required for the recording paper to reach the transfer roller based on the calculated conveying speed. An image forming apparatus. A photosensitive medium, a light scanning device for scanning light onto the photosensitive medium, a developing device for supplying and developing a developer on an electrostatic latent image formed by the light scanning device on the photosensitive medium, and a developing device by the developing device on the photosensitive medium. A transfer roller for transferring the transferred image onto the supplied recording paper, a pick-up roller, and a first sensing sensor disposed at a position spaced apart from the pickup roller by a predetermined distance to detect whether the recording paper has reached the set first detection position. And a second sensing sensor arranged on the paper transfer path between the first sensing sensor and the transfer roller to detect whether the recording sheet has reached the set second detection position. In Calculating a feed rate of the recording paper used to transfer the recording paper from the first sensing sensor to the second sensing sensor by using the output signals of the first sensing sensor and the second sensing sensor; And Determining an optical scanning time point of the optical scanning device by estimating a transfer time required for the recording paper to reach the transfer roller from the second sensor based on the calculated transfer speed. A method of driving an image forming apparatus.