KR20010048636A - Method for control transfer voltage level in image forming apparatus - Google Patents

Abstract

PURPOSE: A transfer voltage controlling method for an image forming apparatus is provided to obtain an optimum transfer voltage in a narrow transfer band by determining a final transfer voltage according to the internal temperature of the image forming apparatus and the existence of a recording paper, thereby providing a high quality printing. CONSTITUTION: A transfer voltage controlling method for an image forming apparatus includes the steps of detecting an internal temperature of the image forming apparatus as a printing instruction is received(S5), detecting a load amount of a transfer roller while a recording paper is not supplied(S7), detecting a load amount of the transfer roller when a picked recording paper reaches the transfer roller(S9), determining a final transfer voltage from a transfer environment recognition table stored in advance in view of a load amount of the transfer roller according to the detected internal temperature and the existence of the recording paper(S19).

Description

Transfer voltage control method of image forming apparatus {METHOD FOR CONTROL TRANSFER VOLTAGE LEVEL IN IMAGE FORMING APPARATUS}

The present invention relates to a method of controlling a transfer voltage of an image forming apparatus, and more particularly, detects an in-board temperature of an image forming apparatus to determine a transfer band, and changes a transfer voltage detection method according to the determined transfer band. The invention relates to a transfer voltage control method of an image forming apparatus capable of detecting an optimal transfer voltage.

Further, the present invention relates to a transfer voltage control method of an image forming apparatus in which a transfer voltage detecting sheet can be reused in a print job by detecting an optimum transfer voltage.

In general, the electrophotographic developing method refers to a method of moving a toner attached to a photosensitive member to a recording paper by using an electric field. In the electrophotographic developing method using a conventional dry toner, the toner on the photosensitive member is transferred to the recording paper with electrostatic force. Corona charger method and bias roller method are available.

The bias roller method is advantageous in miniaturization because the circumference of the transfer roller is in contact with the photosensitive member, and mechanically pressurizes the back surface of the recording sheet in contact with the photosensitive member to provide excellent adhesion and various configurations of the transfer structure of the recording sheet. In addition, since the transfer roller and the photoreceptor are in contact with each other, electrical efficiency can be obtained and the applied voltage can be lowered. Since it is not a discharge method, ozone is not generated, and transfer efficiency is excellent and a high quality output image can be obtained.

The bias rollers generally have an electroconductive soft roller method using a semiconductive sponge in contact with the back surface of a photosensitive member or a recording paper, and an ion conductive hard roller method using a semiconductive rubber.

The transfer voltage required to transfer the toner attached to the photosensitive member onto the recording paper can be expressed by the following equation.

The transfer voltage acts to transfer the transfer potential to the toner potential of the toner layer on the photoconductor to separate the toner layer from the photoconductor and to move the recording paper to the recording paper using an electric field. The remaining toner remaining in the photoconductor in the separated toner layer is charged again by a high-voltage charging voltage and recovered to the developing roller side. The electric field at this time is called a recovery electric field.

Incidentally, the formation of the toner layer on the image portion on the photoconductor is referred to as development, and the development work is carried out using a development bias voltage ( ) And a toner is moved to the photoreceptor to form a visible image by using an electric field caused by the potential difference of the image portion on the photoreceptor.

However, according to the conventional transfer voltage control method, the following problem (s) occur.

That is, in the conventional contact roller type transfer method, since the roller is sensitive to the environment, the transfer environment is recognized, and then the final transfer voltage is determined. However, since the environment is recognized in the absence of paper, the transfer efficiency of the paper varies greatly. Therefore, print quality is reduced.

Therefore, the present invention is to solve such a problem (s), the object of the present invention is to detect the transfer voltage in the section without paper and the section with the paper, respectively, the environment where the transfer band is narrow (transfer for efficient transfer A method of controlling a transfer voltage of an image forming apparatus capable of providing an optimum print quality even in a narrow voltage range) is provided.

In addition, the present invention provides a method of controlling a transfer voltage of an image forming apparatus in which a sheet supplied in order to detect a transfer voltage can be automatically supplied again to prevent waste of the sheet.

1 is a system configuration diagram of an image forming apparatus and a computer applied to the present invention;

2 is a schematic configuration diagram of an image forming apparatus applied to the present invention;

3 is a schematic block diagram of an image forming apparatus applied to the present invention;

4 is an operation flowchart showing a process of performing a transfer voltage control method of an image forming apparatus according to the present invention;

5 is a view showing the format of the transfer voltage detection table applied to the present invention.

<Description of the code | symbol about the principal part of drawing>

204: transfer roller 213: video controller

214: engine controller 215: voltage control unit

216: amplifier 217, 220: high voltage converter

218: feedback part 219: driving part

221: current detection unit 222: solenoid drive unit

223: paper size detection unit 224: cabin temperature detection unit

A feature of the present invention for achieving such an object (s) is an electrophotographic image forming apparatus comprising a transfer roller, comprising: detecting an in-flight temperature of an image forming apparatus when a printing command is received; Detecting a load of the transfer roller in a state where there is no recording paper; Picking up recording paper and detecting a load amount of the transfer roller when the recording paper reaches the transfer roller; Determining a final transfer voltage from a previously stored transfer environment recognition table according to the detected cabin temperature and the load of the transfer roller according to the presence or absence of recording paper; The final transfer voltage determined is supplied to the transfer roller to perform the printing operation.

Here, detecting the size of the recording paper to be conveyed; The final transfer voltage may be determined from a previously stored transfer environment recognition table according to the detected cabin temperature, the load of the transfer roller according to the presence or absence of the recording paper, and the size of the recording paper.

The image forming apparatus further includes a duplex printing apparatus which performs printing on one surface of the recording paper and then flips the recording paper to the printing area so that the other side of the recording paper reaches the printing area; When the final transfer voltage is determined, the recording sheet may be transferred back to the printing area through the duplex printing apparatus, and then the printing operation may be performed.

At this time, the transfer environment recognition table includes: a primary transfer environment recognition table in which load amounts of the transfer roller in the absence of recording paper are divided step by step; An cabin temperature recognition table in which cabin temperatures are divided step by step; A paper size recognition table in which the width size of the recording paper is divided step by step; A secondary transfer environment recognition table in which the load of the transfer roller in the state where the recording paper reaches the transfer roller is divided step by step; And a final transfer voltage table stored in the form of a look-up table to correspond one-to-one to the current transfer environment included in each recognition table.

Hereinafter, exemplary embodiment (s) of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are displayed on different drawings. In addition, in the following description there are shown a number of specific details, such as components of the specific circuit, which are provided only to help a more general understanding of the present invention that the present invention may be practiced without these specific details. It is self-evident to those of ordinary knowledge in Esau. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 shows a system configuration diagram of an image forming apparatus and a computer applied to the present invention, FIG. 2 shows a schematic configuration diagram of an image forming apparatus applied to the present invention, and FIG. 3 an image forming apparatus applied to the present invention. 4 is a block diagram of the transfer voltage control method of the image forming apparatus according to the present invention, and FIG. 5 shows the format of the transfer voltage detection table applied to the present invention. A diagram showing is shown.

First, the configuration of the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the computer 100 and the image forming apparatus (eg, a printer) 200 are connected through a printer cable 300, and as the print data is transmitted from the computer 100, the printer 200. ) Prints after imaging the print data.

On the other hand, an image forming apparatus employing an electrophotographic developing method such as a copying machine, a printer, or the like has a pickup roller 201, a charging roller 202, to print predetermined image data on a printing paper as shown in FIG. An organic photoconductive (OPC) 203, a transfer roller 204, a developing roller 205, a supply roller 206, a fixing unit 207, and an exposure apparatus 208 are formed. That is, when the charging roller 202 charged by the high-voltage charging voltage rotates to evenly charge the photosensitive member applied to the outer circumferential surface of the photosensitive drum 203, the photosensitive drum 203 in which the light generated by the exposure apparatus 208 is charged is charged. The electrostatic latent image to be printed is formed on the surface. Thereafter, a potential difference occurs between the supply roller 206 supplied with the high voltage supply voltage and the developing roller 205 supplied with a voltage lower than the supply roller 206. Thus, the negative charge moves from the feed roller 206 to the developing roller 205. The toner supplied to the developing roller 205 is applied to an electrostatic latent image formed on the surface of the photosensitive drum 203 to form a visible image. The high pressure transfer roller 204 transfers the visible image formed by the toner applied to the surface of the photosensitive drum 203 to the recording paper 209 to be transferred. The visible image transferred to the recording paper 209 is fixed to the recording paper 209 by the high heat and pressure of the heating roller 210 and the pressing roller 211 constituted in the fixing unit 207, thereby completing the printing process.

At this time, the supply voltage, the developing voltage, the transfer voltage, and the charging voltage described above are continuously supplied to the supply roller 206, the developing roller 205, the transfer roller 204, and the charging roller 202 until the printing operation is completed. Supplied. Then, the heating roller 210 in the fixing unit 207 is kept turned on until the printing operation is completed.

In addition, a transfer transfer lamp 212 is provided between the developing roller 205 and the transfer roller 204 to scan the photosensitive drum 203 with light having a wavelength of 650 nm generated by the transfer transfer lamp 212. By lowering the potential of the toner applied to the photosensitive drum 203, the bonding force of the toner to the photosensitive drum 203 is lowered to improve the transfer efficiency.

In addition, the image forming apparatus applied to the present invention is a patent application No. 99-18169 (99.05.20) filed by the present applicant (inventive name: double-sided printing device of an electrophotographic processor) and patent application No. 99-18175 A configuration of a duplex printing apparatus as set forth in (99.05.20) (name of the invention: the duplex printing apparatus of an electrophotographic processor).

Meanwhile, referring to FIG. 3, a schematic configuration of an image forming apparatus applied to the present invention will be described. The video controller 213 converts the print data transmitted from the computer 100 into binary data in the form of a bitmap. .

The engine controller 214 transmits / receives a printer engine and various commands, and at the same time transmits the print data processed by the video controller 213 to the printer engine, and the various operating states, starting time and power of the printer engine. Overall control of supply status and timing.

The voltage controller 215 generates and maintains various voltages (charge voltage, supply voltage, developing voltage, transfer voltage, etc.) supplied to the printer engine under the control of the engine controller 214. Here, the voltage controller 215 is an amplifier 216 for amplifying the pulse width modulated signal THVPWM supplied from the engine controller 214 to a predetermined level, and the transfer roller according to the pulse width modulated signal amplified by the amplifier 216. Compensating the level deviation of the first high voltage converter 217 and the first high voltage converter 217 that generate the transfer voltage (+1.5 [k]) of the level required by 204. To each of the rollers (charge rollers, feed rollers, developing rollers, etc.) except transfer rollers according to an enable signal THVEN supplied from the engine controller 214 and the feedback unit 218 for feeding back the output voltage. The driving unit 219 for selectively controlling the voltage level to be supplied, and the voltage required by each roller according to the control of the driving unit 219, that is, -1.4 [kW] for the charging roller and -800 [V for the supply roller. ], In the case of the developing roller, it generates a voltage of -500 [V], The engine controller 214 loads the transfer roller 204 by detecting the current flowing through the second high voltage converting unit 220 and each roller, in particular, the transfer roller 204, to be supplied to the engine controller 214. It consists of a current detector 221 to detect the.

The solenoid drive unit 222 controls the operation state by the solenoid drive signal S-DRV from the engine controller 214 to switch the operation state of the duplex printing device to the single-sided printing mode and the double-sided printing mode.

The paper size detection unit 223 detects the size of the paper supplied by being mounted in a cassette in which a plurality of sheets of paper are stacked. Since the mechanical configuration of the paper size detection unit 223 corresponds to a well-known technique, a separate description will be omitted.

The cabin temperature detection unit 224 detects the cabin temperature of the image forming apparatus and provides the result to the engine controller 214 so that the engine controller 214 can determine the transfer band.

Referring to Figures 4 and 5 with respect to the operation of the present invention having such a configuration as follows.

First, a table for transferring environment recognition as shown in FIG. 5 is stored in a memory in the engine controller 214. As shown, the transfer band according to the range of the load amount of the transfer roller 204 in the section where there is no paper in the table, the cabin temperature detected by the cabin temperature detector 224, and the paper size detector 223 are detected. The final transfer voltage corresponding to each transfer environment such as the transfer width according to the width size of the printed paper and the range of the load amount of the transfer roller 204 in the section where the paper is present is set.

First, when power is applied, the engine controller 214 warms up the device to a predetermined temperature by performing a warm-up (S1). Thereafter, when the preparation operation is completed, the interface with the video controller 213 is performed. That is, when a print command is received from the computer, the video controller 213 generates print data and outputs a print command signal / PRINT to the engine controller 214.

When the print command signal / PRINT is received from the video controller 213 (S2), the engine controller 214 picks up the recording paper 209 loaded in the cassette (S3). At this time, the engine controller 214 should determine the transfer voltage before the recording paper 209 reaches the feed sensor. That is, the engine controller 214 determines whether the transfer environment recognition operation is required (S4), and if the transfer environment recognition operation is required, the engine controller 214 controls the in-flight temperature detector 224 to adjust the temperature value in the cabin. It is detected (S5). For example, if the cabin temperature is 35 ° C. or higher, the transfer band is narrow, so that the normal transfer operation is not performed unless the transfer voltage is set correctly. Therefore, the engine controller 214 detects the load amount of the transfer roller 204 by controlling the current detector 221 in the absence of the recording sheet 209, and stores the detected load amount in the primary transfer environment recognition table (Fig. The corresponding load range is detected in comparison with the load range in step 5) (S7).

Thereafter, the engine controller 214 controls the paper size detection unit 223 to detect the size of the recording paper 209 to be conveyed (S8), and in the state in which the paper is conveyed in correspondence with the detected size of the recording paper 209. The load amount of the transfer roller 204 is detected (S9), and the detected load amount is compared with the load range in the secondary transfer environment recognition table (see FIG. 5) stored in the memory to determine the final transfer voltage according to the corresponding load range. (S10).

When the final transfer voltage is determined according to the above process, the engine controller 214 controls the solenoid drive unit 222 to transfer the recording paper 209 to the duplex printing apparatus (not shown) (S11), and then the recording paper ( 209 determines whether it is detected by the feed sensor again (S12). When the recording sheet 209 is detected by the feed sensor, the engine controller 214 outputs the page synchronization signal PAGE-SYNC to the video controller 213 (S13). Accordingly, the video controller 213 transmits one page amount of print data to the engine controller 214, and the engine controller 214 drives the printer engine to print one page amount of print data (S14). At this time, the engine controller 214 determines whether the duplex printing function is selected by the user (S15), and when it is determined that the duplex printing function is selected, the engine controller 214 controls the solenoid drive unit 222 to turn the recording paper 209 into the duplex printing apparatus. After the transfer, a duplex printing operation for printing the print data of the next page on the back side of the recording paper 209 is performed (S16). If it is determined in step S15 that the duplex printing function is not selected, the solenoid driving unit 22 is controlled to discharge the recording paper 209 to the exit tray to end the printing operation for one page. (S17).

If, in the above step (S6), the cabin temperature is 35 ° C. or less, and the transfer band is determined to be wide, the load of the transfer roller 204 is reduced in the absence of the recording paper 209 in the same manner as the general transfer voltage determination method. After detection (S18), the final transfer voltage corresponding to the load amount is determined (S19). The subsequent process is the same as the process after step S12 mentioned above.

On the other hand, if it is determined that the environmental recognition is not necessary in the above step (S4), the process of recognizing the transfer environment is omitted, and proceeds directly to the aforementioned step (S12) to perform a print job.

Therefore, the optimum transfer voltage can be set even in an environment where the transfer band is narrow.

As described above, although the specific embodiment (s) have been described in the detailed description of the present invention, various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiment (s) but should be defined by the claims below and equivalents thereof.

As a result, according to the transfer voltage control method of the image forming apparatus according to the present invention, the following advantage (s) occurs.

That is, according to the cabin temperature, the primary transfer environment is detected in the absence of recording paper in the environment where the transfer band is narrow, the recording paper is transported to redetect the secondary transfer environment, and then, according to the detected primary and secondary transfer environments. By determining the final transfer voltage, an optimum transfer voltage can be obtained even in an environment where the transfer band is narrow. Therefore, optimum print quality can be maintained.

In addition, by determining the transfer voltage in consideration of the size of the recording paper, it is possible to maximize the optimization of the transfer voltage.

In addition, by automatically transporting the recording paper used for detecting the transfer environment to the first printing position through the duplex printing apparatus, waste of the recording paper can be prevented.

Claims (4)

In an electrophotographic image forming apparatus comprising a transfer roller: Detecting a cabin temperature of the image forming apparatus when a printing command is received; Detecting a load of the transfer roller in a state where there is no recording paper; Picking up recording paper and detecting a load of the transfer roller when the recording paper reaches the transfer roller; Determining a final transfer voltage from a previously stored transfer environment recognition table according to the detected cabin temperature and the load of the transfer roller according to the presence or absence of the recording sheet; And And supplying the determined final transfer voltage to the transfer roller to perform a printing operation. The method of claim 1, Sensing the size of the recording paper to be conveyed; The determining of the final transfer voltage may include determining a final transfer voltage from a pre-stored transfer environment recognition table according to the detected load temperature of the transfer roller according to the detected cabin temperature, the presence or absence of the recording paper, and the size of the recording paper. Transfer voltage control method of the forming apparatus. The method of claim 2, The image forming apparatus further includes a duplex printing apparatus for performing a printing operation on one surface of the recording paper, and then turning the recording sheet over to the printing area so that the other side of the recording paper reaches the printing area; When the final transfer voltage is determined in the final transfer voltage determination step, the recording sheet is transferred again to the printing area through the double-sided printing apparatus and then the printing step is performed. Control method. The method of claim 3, wherein the transfer environment recognition table, A primary transfer environment recognition table in which the load of the transfer roller in the state where there is no recording paper is divided step by step; An cabin temperature recognition table in which the cabin temperature is divided step by step; A paper size recognition table in which the width size of the recording paper is divided step by step; A secondary transfer environment recognition table in which loads of the transfer roller are divided step by step when the recording paper reaches the transfer roller; And And a final transfer voltage table stored in the form of a look-up table in a one-to-one correspondence with the current transfer environment included in each of the recognition tables.