JP2014043079A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of increasing an image writing speed while suppressing costs.SOLUTION: An image forming device includes a plurality of LSIs 201 and 251. The plurality of LSIs 201 and 251 includes main scanning synchronous signal input/output parts 211 and 261 capable of inputting/outputting a main scanning synchronous signal used for synchronizing positions in a main scanning direction between the plurality of LSIs 201 and 251, start signal input/output parts 213 and 263 capable of inputting/outputting a start signal which is a writing trigger per line unit of image data, and writing control units 215 and 265 for controlling writing timing of the image data based on the main scanning synchronous signal and the start signal.

Description

  The present invention relates to an image forming apparatus.

  In an electrophotographic image forming apparatus such as a laser printer or a digital copying machine, the image writing speed is increasing year by year. In such an image forming apparatus, a method of improving the image writing speed by simultaneously writing images for a plurality of lines from a laser light source is the mainstream, but if the number of simultaneous writing lines is increased, a writing control LSI (Large Scale Integration) and other write control units are overwhelming, increasing the development burden.

  For this reason, for example, Patent Document 1 does not make the configuration of the write control LSI large, but by combining a plurality of write control LSIs, the number of simultaneous write lines is increased and the image write speed is increased. A method for improving the number has been proposed.

  In the conventional technology as described above, when a plurality of write control units are used in combination, a dedicated LSI that performs synchronization to suppress image misalignment is separately required. Is not required when using alone. For this reason, when the case where the write control unit is used alone is considered, an unnecessary configuration is added, resulting in an increase in cost.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming apparatus capable of improving the image writing speed while suppressing the cost.

  In order to solve the above-described problems and achieve the object, an image forming apparatus according to an aspect of the present invention is an image forming apparatus including a plurality of write control devices, each of the plurality of write control devices. A main scanning synchronization signal input / output unit capable of inputting / outputting a main scanning synchronization signal used for position synchronization in the main scanning direction between the plurality of writing control devices, and a trigger for writing image data in line units, A start signal input / output unit capable of inputting and outputting a start signal, and a write control unit for controlling the writing timing of the image data based on the main scanning synchronization signal and the start signal.

  According to the present invention, it is possible to improve the image writing speed while suppressing the cost.

FIG. 1 is a schematic diagram illustrating an example of the overall configuration of the printing apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating an example of a functional configuration of the printing apparatus according to the first embodiment. FIG. 3 is a block diagram illustrating an example of a functional configuration of the write control mechanism according to the first embodiment. FIG. 4 is a diagram illustrating an example of a timing chart of the write control mechanism according to the first embodiment. FIG. 5 is a block diagram illustrating an example of a functional configuration of the write control mechanism of the second embodiment. FIG. 6 is a diagram illustrating an example of a timing chart of the write control mechanism of the second embodiment. FIG. 7 is a schematic diagram illustrating an example of the overall configuration of the printing apparatus according to the fifth modification. FIG. 8 is a schematic diagram illustrating an example of the overall configuration of the printing apparatus according to the sixth modification.

  Hereinafter, embodiments of an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. In the following embodiments, the case where the image forming apparatus of the present invention is applied to an electrophotographic printing apparatus will be described as an example. However, the present invention is not limited to this. The image forming apparatus of the present invention can be applied to any apparatus that forms an image by electrophotography, and can be applied to, for example, an electrophotographic copying machine or a multifunction peripheral (MFP). Note that a multifunction peripheral is a device having at least two functions among a printing function, a copying function, a scanner function, and a facsimile function.

(First embodiment)
FIG. 1 is a schematic diagram illustrating an example of the overall configuration of a printing apparatus 10 according to the first embodiment. As shown in FIG. 1, the printing apparatus 10 includes a paper feed tray 12, a paper feed roller 14, a separation roller pair 16, an image forming unit 18, and a fixing unit 40. In the example shown in FIG. 1, as will be described later, a so-called tandem type printing apparatus in which image forming units of respective colors are arranged along a conveyance belt is shown, but the present invention is not limited to this. .

  A plurality of recording sheets are stacked and stored in the sheet feeding tray 12.

  The paper feed roller 14 is in contact with the recording paper P positioned at the top of the paper supply tray 12 and feeds the recording paper P in contact therewith.

  The separation roller pair 16 sends the recording paper P fed by the paper feed roller 14 to the image forming unit 18. When two or more recording sheets are fed by the sheet feeding roller 14, the separation roller pair 16 pushes back the recording sheet other than the recording sheet P, so that the recording sheets other than the recording sheet P and the recording sheet P are recorded. The paper is separated and only the recording paper P is sent to the image forming unit 18.

  The image forming unit 18 forms an image on the recording paper P sent from the pair of separation rollers 16, and includes image forming units 20B, 20M, 20C, and 20Y, and LEDA (Light Emitting Diode Array) heads 32B1, 32B2. , 32M1, 32M2, 32C1, 32C2, 32Y1, and 32Y2, a conveyor belt 34, a driving roller 36, and a driven roller 38.

  The image forming units 20B, 20M, 20C, and 20Y are in the order of the image forming units 20B, 20M, 20C, and 20Y from the upstream side in the transport direction of the transport belt 34 that transports the recording paper P sent from the separation roller pair 16. Are arranged along the conveyor belt 34.

  The image forming unit 20B includes a photosensitive drum 22B, and a charger 24B, a developing unit 26B, a transfer unit 28B, a photosensitive cleaner (not shown), and a static eliminator 30B disposed around the photosensitive drum 22B. The image forming unit 20B and the LEDA heads 32B1 and 32B2 perform an image forming process (charging process, exposure process, developing process, transfer process, cleaning process, and charge eliminating process) on the photoconductive drum 22B. A black toner image is formed on 22B.

  The image forming units 20M, 20C, and 20Y all have the same components as the image forming unit 20B. The image forming unit 20M forms a magenta toner image by performing an image forming process. The image forming unit 20C forms a cyan toner image by performing an image forming process, and the image forming unit 20Y forms a yellow toner image by performing an image forming process. Therefore, in the following, description will be made mainly on the components of the image forming unit 20B, and the components of the image forming units 20M, 20C, and 20Y will be denoted by B attached to the reference numerals of the components of the image forming unit 20B. Instead, only M, C, and Y are attached, and the description thereof is omitted.

  The photosensitive drum 22B is rotationally driven by a drive motor (not shown).

  First, in the charging step, the charger 24B uniformly charges the outer peripheral surface of the rotationally driven photosensitive drum 22B in the dark.

  Subsequently, in the exposure process, the LEDA heads 32B1 and 32B2 expose the outer peripheral surface of the rotationally driven photosensitive drum 22B with irradiation light corresponding to the black image, and electrostatically based on the black image on the photosensitive drum 22B. A latent image is formed. Here, the LEDA heads 32B1 and 32B2 (an example of a plurality of non-scanning writing units) are arranged (disposed) in the sub-scanning direction with respect to the photosensitive drum 22B, and are arranged on the photosensitive drum 22B. On the other hand, image information for a plurality of lines can be simultaneously written. As a result, the image writing speed can be increased. The same applies to the LEDA heads 32M1, 32M2, the LEDA heads 32C1, 32C2, and the LEDA heads 32Y1, 32Y2.

  In the case of the photosensitive drum 22M, the LEDA heads 32M1 and 32M2 expose the outer peripheral surface with irradiation light corresponding to the magenta image. In the case of the photosensitive drum 22C, the LEDA heads 32C1 and 32C2 convert the outer peripheral surface to a cyan image. In the case of the photosensitive drum 22Y, the LEDA heads 32Y1 and 32Y2 expose the outer peripheral surface with the irradiation light corresponding to the yellow image.

  Subsequently, in the developing process, the developing device 26B develops the electrostatic latent image formed on the photosensitive drum 22B with black toner, and forms a black toner image on the photosensitive drum 22B.

  Subsequently, in the transfer process, the transfer device 28B transfers the black toner image formed on the photosensitive drum 22B to the recording paper at the transfer position where the photosensitive drum 22B and the recording paper P conveyed by the conveying belt 34 are in contact with each other. Transfer to P. Note that a small amount of untransferred toner remains on the photosensitive drum 22B even after the toner image is transferred.

  Subsequently, in the cleaning process, the photoreceptor cleaner wipes off the untransferred toner remaining on the photoreceptor drum 22B.

  Finally, in the static elimination process, the static eliminator 30B neutralizes the residual potential on the photosensitive drum 22B. Then, the image forming unit 20B waits for the next image formation.

  The conveying belt 34 is an endless belt wound around a driving roller 36 and a driven roller 38, and the recording paper P sent from the separation roller pair 16 is adsorbed by an electrostatic adsorption action. The transport belt 34 is moved endlessly by the drive roller 36 being rotated by a drive motor (not shown), and transports the adsorbed recording paper P in the order of the image forming units 20B, 20M, 20C, and 20Y.

  The black toner image is first transferred to the recording paper P conveyed by the conveying belt 34 by the image forming unit 20B, then the magenta toner image is transferred by the image forming unit 20M, and the cyan toner image is transferred by the image forming unit 20C. A yellow toner image is superimposed and transferred by the toner image and image forming unit 20Y. As a result, a full-color image is formed on the recording paper P.

  The fixing unit 40 fixes the full color image formed by the image forming units 20 </ b> B, 20 </ b> M, 20 </ b> C, and 20 </ b> Y on the recording paper P by heating and pressurizing the recording paper P peeled from the conveyance belt 34. The recording paper P on which the image is fixed is discharged outside the printing apparatus 10.

  FIG. 2 is a block diagram illustrating an example of a functional configuration of the printing apparatus 10 according to the first embodiment. As illustrated in FIG. 2, the printing apparatus 10 includes an operation display unit 101, a storage unit 103, a computer interface unit 105, a reading unit 107, a controller 109, a control unit 111, a line memory 113, and a writing A control mechanism 115, an image forming process unit 117, a pattern output unit 119, and a fixing unit 121 are provided.

  The operation display unit 101 displays various operations and various screens, and can be realized by a touch panel display or the like.

  The storage unit 103 stores various programs executed by the printing apparatus 10 and data used for various processes performed by the printing apparatus 10. The storage unit 103 is, for example, magnetic, optical, or electrical such as a hard disk drive (HDD), a solid state drive (SSD), a memory card, an optical disk, a read only memory (ROM), and a random access memory (RAM). This can be realized by a storage device that can be stored.

  The computer interface unit 105 communicates with a print request source terminal such as a host device via a communication interface (not shown) such as a network, and accepts a print job such as image data. The computer interface unit 105 can be realized by a communication device such as a NIC (Network Interface Card).

  The reading unit 107 optically reads a document, converts print information of the document into an electrical signal, and generates image data.

  The controller 109 manages the print order of the print jobs received by the computer interface unit 105, transmits the print job in the print order to the control unit 111, and requests printing of the print job.

  The control unit 111 receives a print job from the controller 109 and controls the line memory 113, the image forming process unit 115, the writing control unit 117, the pattern output unit 119, the fixing unit 121, and the like to print the print job. Run.

  The line memory 113 stores image data sequentially transmitted from the control unit 111 in units of lines.

  The write control mechanism 115 sequentially reads out image data in line units from the line memory 113, and uses the read image data as a signal for emitting light from the LEDA heads 32B1, 32B2, 32M1, 32M2, 32C1, 32C2, 32Y1, and 32Y2. The image data is written by emitting (lighting) the LEDA heads 32B1, 32B2, 32M1, 32M2, 32C1, 32C2, 32Y1, and 32Y2 based on the converted signals. The write control mechanism 115 performs skew correction on the image data by controlling the timing of reading the image data from the line memory 113.

  The image forming process unit 117 executes an electrophotographic image forming process in conjunction with the writing of image data by the writing control mechanism 115 to create a toner image and transfer it to a sheet. Note that the image forming process unit 117 corrects a position shift or the like when it is detected.

  The pattern output unit 119 generates and outputs an arbitrary pattern such as a positional deviation correction pattern.

  The fixing unit 121 fixes the toner image on the paper by applying heat and pressure to the paper on which the toner image is transferred.

  FIG. 3 is a block diagram illustrating an example of a functional configuration of the write control mechanism 115 according to the first embodiment. In the example shown in FIG. 3, an example is shown in which the write control mechanism 115 is configured by two LSIs (Large Scale Integration), which are examples of a plurality of write control devices. You may comprise by 3 or more LSI. The LSI may be, for example, an ASIC (Application Specific Integrated Circuit). Further, when the write control mechanism 115 is constituted by two or more LSIs, any one is a master and the others are slaves.

  In the first embodiment, since up to four LEDAs can be controlled by one LSI, the write control mechanism 115 is configured by two LSIs, and eight LEDAs (LEDA heads 32B1, 32B2, 32M1, 32M2, 32C1, 32C2, 32Y1, and 32Y2) are controlled, but the present invention is not limited to this.

  As shown in FIG. 3, the write control mechanism 115 includes an LSI (master) 201 (an example of a master write control device, hereinafter referred to as “LSI 201”) and an LSI (slave) 251 (of the slave write control device). For example, hereinafter, it is referred to as “LSI 251”).

  The LSI 201 includes an external terminal 203, a determination unit 205, a main scanning synchronization signal input / output unit 211, a start signal input / output unit 213, a write control unit 215, a first internal counter 221, and a second internal counter 223. And a register 225. The LSI 251 also includes an external terminal 253, a determination unit 255, a main scanning synchronization signal input / output unit 261, a start signal input / output unit 263, a write control unit 265, a first internal counter 271, and a second internal counter. 273 and a register 275. As described above, the LSI 201 and the LSI 251 have the same hardware configuration.

  The determination unit 205 and the determination unit 255 determine whether the LSI 201 and the LSI 251 are to be masters or slaves, respectively. Specifically, the determination unit 205 and the determination unit 255 determine whether the LSI 201 and the LSI 251 are set as a master or a slave based on voltages applied to the external terminal 203 and the external terminal 253, respectively.

  In the first embodiment, the LSI to which the power supply voltage VDD is applied is set as the slave, and the LSI to which the ground voltage is applied is set as the master. In the example shown in FIG. 3, the power supply voltage VDD is applied to the external terminal 253. Therefore, the determination unit 255 determines the LSI 251 as a slave, and since the ground voltage is applied to the external terminal 203, the determination unit 205 determines the LSI 201 as a master.

  The main scanning synchronization signal input / output unit 211 and the main scanning synchronization signal input / output unit 261 can input / output a main scanning synchronization signal used for position synchronization between the LSI 201 and the LSI 251 in the main scanning direction. This can be realized with an output terminal.

  In the first embodiment, the main scanning synchronization signal input / output unit on the master side outputs a main scanning synchronization signal, and the main scanning synchronization signal input / output unit on the slave side inputs a main scanning synchronization signal. In the example shown in FIG. 3, the main scanning synchronization signal input / output unit 211 outputs the main scanning synchronization signal in units of lines, and the main scanning synchronization signal input / output unit 261 receives the main scanning synchronization signal.

  The start signal input / output unit 213 and the start signal input / output unit 263 can input / output a start signal serving as a trigger for writing image data in units of lines, and can be realized by an input / output terminal, for example.

  In the first embodiment, the start signal input / output unit on the master side outputs a start signal, and the start signal input / output unit on the slave side inputs a start signal. In the example shown in FIG. The input / output unit 213 outputs a start signal, and the start signal input / output unit 263 inputs the output start signal.

  The writing control unit 215 and the writing control unit 265 control the writing timing of the image data based on the main scanning synchronization signal and the start signal. Specifically, the writing control unit 215 synchronizes every time the main scanning synchronization signal is output, and starts writing at the timing of synchronization when the writing start condition is satisfied, and is determined in advance. The start signal input / output unit 213 outputs the start signal with a delay of the second delay amount. The writing control unit 265 synchronizes with the LSI 201 by delaying a predetermined first delay amount every time the main scanning synchronization signal is input, and at the timing of synchronization when the start signal is input. Start writing. In the first embodiment, the first delay amount and the second delay amount are assumed to be in clock units.

  Hereinafter, a specific control method of the write timing of the write control unit 215 and the write control unit 265 will be described with reference to FIG. FIG. 4 is a diagram illustrating an example of a timing chart of the write control mechanism 115 according to the first embodiment. In the example illustrated in FIG. 4, an example in which the LSI 201 and the LSI 251 are synchronized in units of one line will be described, but the present invention is not limited to this. For example, synchronization may be performed in units of two lines or units of four lines. .

  First, the LSI 201 side will be described.

  The first internal counter 221 and the second internal counter 223 count the number of clocks. When counting to 3F1E (hexadecimal number), the count starts from 0 again. Note that the second internal counter 223 performs counting one clock later than the first internal counter 221.

  When the first internal counter 221 counts up to 3F1E (hexadecimal), the writing control unit 215 causes the main scanning synchronization signal input / output unit 211 to output a main scanning synchronization signal. Further, when the second internal counter 223 counts to 0 (hexadecimal number), the writing control unit 215 raises an internal main scanning synchronization signal.

  When an asynchronous start signal for register setting is set in the register 225, the write control unit 215 sets the internal control signal in synchronization with the rise of the first internal main scanning synchronization signal after the start signal is set. The start signal is raised (asserted), and writing control of the image data transferred from the line memory 113 is performed.

  When the internal control start signal rises, the write control unit 215 delays the clock by 4 clocks (an example of the second delay amount) and causes the start signal input / output unit 213 to output the start signal. Note that the second delay amount may be any delay amount that can be accommodated in an interval at which the main scanning synchronization signal input / output unit 211 outputs the main scanning synchronization signal, that is, one line.

  Next, the LSI 251 side will be described.

  The first internal counter 271 and the second internal counter 273 count the number of clocks. When counting to 3F1E (hexadecimal number), the count starts from 0 again. The second internal counter 273 performs counting with a delay of one clock from the first internal counter 271.

  When a main scanning synchronization signal is input to the main scanning synchronization signal input / output unit 261, the first internal counter 271 delays by two clocks (an example of a first delay amount), initializes the count, and counts from 0 again. . The first delay amount becomes a known delay amount (2 clocks in the first embodiment) by synchronizing the LSI 201 and the LSI 251 in units of lines. Then, when the first internal counter 271 initializes the count, the writing control unit 255 raises the internal first main scanning synchronization signal. The internal first main scanning synchronization signal is a signal obtained by delaying the main scanning synchronization signal input to the main scanning synchronization signal input / output unit 261 by two clocks.

  When the internal first main scanning synchronization signal rises, the second internal counter 273 initializes the count after 1 clock and starts counting from 0 again. Then, when the second internal counter 273 counts to 0 (hexadecimal number), the writing control unit 265 raises the internal second main scanning synchronization signal.

  Further, when the start signal is input to the start signal input / output unit 263, the writing control unit 265 performs internal use in accordance with the rising of the first internal second main scanning synchronization signal after the start signal is input. The start signal is raised (asserted), and writing control of the image data transferred from the line memory 113 is performed.

  As described above, in the first embodiment, since writing is performed using the LEDA, there is no need to scan the laser, and the LSI controls the writing timing with the internal counter. For this reason, in the first embodiment, synchronization between a plurality of LSIs can be achieved by using the main scanning synchronization signal and the start signal, and the image writing speed can be improved while suppressing the cost. In particular, in the first embodiment, there is no need for a dedicated LSI or the like that performs synchronization for suppressing image misalignment, so that the cost of using an LSI alone can be significantly reduced.

  In the first embodiment, since synchronization is performed in units of lines, the synchronization (main scanning synchronization) timing between a plurality of LSIs can be set to a known delay amount, and the main scanning synchronization signal and the start signal are used. By controlling the main scanning timing, writing can be performed in synchronization between a plurality of LSIs, and position shift control of the writing position can be performed. Thereby, in the first embodiment, the hardware configuration of each LSI can be made common, and the operation of each LSI can be made common except for the input and output of the main scanning synchronization signal and the start signal. It can be used for both LSI and single LSI.

  In addition, according to the first embodiment, since delay control is performed on the slave side to which the main scanning synchronization signal and the start signal are input, it is possible to cope with delay due to signal transmission, and precise synchronization can be achieved among a plurality of LSIs. Therefore, the positional deviation control of the writing position can be performed precisely.

(Second Embodiment)
In the second embodiment, a write control example different from that in the first embodiment will be described. In the following, differences from the first embodiment will be mainly described, and components having the same functions as those in the first embodiment will be given the same names and symbols as those in the first embodiment, and the description thereof will be made. Omitted.

  FIG. 5 is a block diagram illustrating an example of a functional configuration of the write control mechanism 315 according to the second embodiment. As shown in FIG. 5, in the write control mechanism 315 of the second embodiment, a write control unit 415 of an LSI (master) 401 (hereinafter referred to as “LSI 401”) and an LSI (slave) 451 (hereinafter referred to as “ The write control unit 465 (referred to as “LSI 451”) is different from the first embodiment.

  The writing control unit 415 synchronizes with the LSI 451 by delaying a predetermined first delay amount every time the main scanning synchronization signal is output, and synchronizes when the writing start condition is satisfied. Writing is started at the timing, and a start signal is output to the start signal input / output unit 213 after being delayed by a predetermined second delay amount. The writing control unit 465 synchronizes with the LSI 401 by delaying a predetermined first delay amount every time the main scanning synchronization signal is input, and at the timing of synchronization when the start signal is input. Start writing.

  Hereinafter, a specific control method of the write timing of the write control unit 415 and the write control unit 465 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of a timing chart of the write control mechanism 315 of the second embodiment.

  First, the LSI 401 side will be described.

  The first internal counter 221 and the second internal counter 223 count the number of clocks. When counting to 3F1E (hexadecimal number), the count starts from 0 again. Note that the second internal counter 223 performs counting one clock later than the first internal counter 221.

  When the first internal counter 221 counts up to 3F1E (hexadecimal), the writing control unit 415 causes the main scanning synchronization signal input / output unit 211 to output a main scanning synchronization signal. When the second internal counter 223 counts to 0 (hexadecimal number), the writing control unit 415 raises the internal first main scanning synchronization signal. Further, when the internal first main scanning synchronization signal is raised, the writing control unit 415 delays 2 clocks (an example of the first delay amount) and raises the internal second main scanning synchronization signal. The internal second main scanning synchronization signal is a signal obtained by delaying the internal first main scanning synchronization signal by two clocks.

  Further, when an asynchronous start signal for register setting is set in the register 225, the write control unit 415 performs internal control in accordance with the rise of the first internal second main scanning synchronization signal after the start signal is set. Is started (asserted), and writing control of the image data transferred from the line memory 113 is performed.

  When the internal control start signal rises, the write control unit 415 delays the clock by 2 clocks (an example of the second delay amount) and causes the start signal input / output unit 213 to output the start signal. Note that the second delay amount may be any delay amount that can be accommodated in an interval at which the main scanning synchronization signal input / output unit 211 outputs the main scanning synchronization signal, that is, one line.

  Next, the LSI 451 side will be described.

  The first internal counter 271 and the second internal counter 273 count the number of clocks. When counting to 3F1E (hexadecimal number), the count starts from 0 again. The second internal counter 273 performs counting with a delay of one clock from the first internal counter 271.

  When a main scanning synchronization signal is input to the main scanning synchronization signal input / output unit 261, the first internal counter 271 delays by two clocks (an example of a first delay amount), initializes the count, and counts from 0 again. . The first delay amount is a known delay amount (2 clocks in the first embodiment) by synchronizing the LSI 401 and the LSI 451 in units of lines. Then, when the first internal counter 271 initializes the count, the writing control unit 455 raises the internal first main scanning synchronization signal. The internal first main scanning synchronization signal is a signal obtained by delaying the main scanning synchronization signal input to the main scanning synchronization signal input / output unit 261 by two clocks.

  When the internal first main scanning synchronization signal rises, the second internal counter 273 initializes the count after 1 clock and starts counting from 0 again. When the second internal counter 273 counts to 0 (hexadecimal), the writing control unit 465 raises the internal second main scanning synchronization signal.

  Further, when the start signal is input to the start signal input / output unit 263, the writing control unit 465 performs the internal control in accordance with the rise of the first internal second main scanning synchronization signal after the start signal is input. The start signal is raised (asserted), and writing control of the image data transferred from the line memory 113 is performed.

  As described above, in the second embodiment, synchronization (main scanning synchronization) of the LSI 401 (master) is delayed in advance, so that synchronization can be achieved at the same timing among a plurality of LSIs. Thereby, also in 2nd Embodiment, there can exist an effect similar to 1st Embodiment.

(Modification)
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

(Modification 1)
In each of the embodiments described above, the determination unit determines whether to use the LSI as a master or a slave based on the voltage applied to the external terminal 203. However, based on the register value stored in the register, the determination unit determines that the LSI is the master. Or a slave may be determined.

(Modification 2)
In each of the above-described embodiments, the example in which the main scanning synchronization signal input / output unit and the start signal input / output unit are realized by the input / output terminals has been described. However, it may be realized by a combination of the input terminal and the output terminal.

(Modification 3)
In each of the above embodiments, an example in which a plurality of LEDs A are arranged in the sub-scanning direction with respect to the photoreceptor has been described. However, a plurality of LEDs A are arranged in the main scanning direction with respect to the photoreceptor, and the plurality of LEDs A are arranged in a plurality of ways. You may make it write-control by LSI. In this way, it is possible to deal with large-size recording paper.

(Modification 4)
In each of the above embodiments, an example in which a plurality of LEDs A are arranged in the sub-scanning direction with respect to the photoconductor has been described. However, a single LEDA is arranged in the main scanning direction with respect to the photoconductor, and the single LEDA is arranged into a plurality of LEDs. You may make it write-control by LSI. In this way, it is possible to deal with large-size recording paper.

(Modification 5)
In each of the above embodiments, the case where there are four pairs of image forming units and LEDAs (hereinafter referred to as “stations”) has been described. However, as illustrated in FIG. 7, the number may be five or more. Good. For example, as shown in FIG. 7, if the number of stations is five or more, it is possible to form an image using clear toner in addition to YMCK toner, thereby improving the color expression.

(Modification 6)
In each of the above-described embodiments and modifications, the example in which the write control unit is configured by two LSIs and controls five or more LEDs A has been described. However, when there are four LEDAs as shown in FIG. The write control unit may be composed of a single LSI.

DESCRIPTION OF SYMBOLS 10 Printing apparatus 12 Paper feed tray 14 Paper feed roller 16 Separation roller pair 18 Image formation part 20B, 20M, 20C, 20Y Image formation part 22B, 22M, 22C, 22Y Photosensitive drum 24B, 24M, 24C, 24Y Charger 26B, 26M, 26C, 26Y Developer 28B, 28M, 28C, 28Y Transfer device 30B, 30M, 30C, 30Y Charger 32B1, 32B2, 32M1, 32M2, 32C1, 32C2, 32Y1, 32Y2 LEDA head 34 Conveyor belt 36 Drive roller 38 Driven Roller 40 Fixing unit 101 Operation display unit 103 Storage unit 105 Computer interface unit 107 Reading unit 109 Controller 111 Control unit 113 Line memory 115, 315 Write control mechanism 117 Image forming process unit 119 Pattern output unit 121 Wearing part 201,401 LSI
203 External Terminal 205 Determination Unit 211 Main Scanning Sync Signal Input / Output Unit 213 Start Signal Input / Output Unit 215, 415 Write Control Unit 221 First Internal Counter 223 Second Internal Counter 225 Register 251, 451 LSI
253 External terminal 255 Determination unit 261 Main scanning synchronization signal input / output unit 263 Start signal input / output unit 265, 465 Write control unit 271 First internal counter 273 Second internal counter 275 Register

JP 2002-283625 A

Claims (15)

An image forming apparatus comprising a plurality of writing control devices,
Each of the plurality of write control devices includes:
A main scanning synchronization signal input / output unit capable of inputting / outputting a main scanning synchronization signal used for synchronizing positions in the main scanning direction between the plurality of writing control devices;
A start signal input / output unit capable of inputting / outputting a start signal as a trigger for writing image data in units of lines;
A writing control unit for controlling the writing timing of the image data based on the main scanning synchronization signal and the start signal;
An image forming apparatus comprising: The plurality of write control devices are a master write control device and a slave write control device,
In the master write control device,
The main scanning synchronization signal input / output unit outputs the main scanning synchronization signal in units of lines,
The start signal input / output unit outputs the start signal,
In the slave write control device,
The main scanning synchronization signal input / output unit inputs the main scanning synchronization signal,
The image forming apparatus according to claim 1, wherein the start signal input / output unit inputs the start signal. In the slave write control device,
Each time the main scanning synchronization signal is input, the writing control unit delays a predetermined first delay amount to synchronize with the master writing control device, and when the start signal is input The image forming apparatus according to claim 2, wherein writing is started at a timing of synchronization. In the master write control device,
The writing control unit synchronizes every time the main scanning synchronization signal is output, and when writing start conditions are satisfied, starts writing at the timing of synchronization,
The image forming apparatus according to claim 3, wherein the start signal input / output unit outputs the start signal with a predetermined second delay amount when writing by the write control unit is started. In the master write control device,
When the write control unit synchronizes with the slave write control device by delaying a predetermined first delay amount each time the main scanning synchronization signal is output and the write start condition is satisfied Start writing at the timing of synchronization,
The image forming apparatus according to claim 2, wherein the start signal input / output unit outputs the start signal with a predetermined second delay amount when writing by the write control unit is started. In the slave write control device,
The write control unit delays the first delay amount every time the main scanning synchronization signal is input, and synchronizes with the master write control device. When the start signal is input, the write control unit synchronizes. The image forming apparatus according to claim 5, wherein writing is started at a timing to take.   The image forming apparatus according to claim 4, wherein the first delay amount and the second delay amount are in units of clocks. Each of the plurality of write control devices includes:
The image forming apparatus according to claim 1, further comprising a determination unit that determines whether the device is a master writing control device or a slave writing control device. Each of the plurality of write control devices includes:
With external terminals,
The image forming apparatus according to claim 8, wherein the determination unit determines whether to use the master writing control device or the slave writing control device based on a voltage applied to the external terminal.   The image forming apparatus according to claim 8, wherein the determination unit determines whether to use the master writing control device or the slave writing control device based on a register value. A photoreceptor,
A plurality of non-scanning writing units arranged in the sub-scanning direction with respect to the photosensitive member;
The image forming apparatus according to claim 1, further comprising: A photoreceptor,
A plurality of non-scanning writing units arranged in the main scanning direction with respect to the photosensitive member;
The image forming apparatus according to claim 1, further comprising: A photoreceptor,
A non-scanning type writing unit disposed in the main scanning direction with respect to the photosensitive member,
Each of the plurality of write control devices includes:
The image forming apparatus according to claim 1, wherein writing by the non-scanning writing unit is controlled.   The image forming apparatus according to claim 11, comprising a plurality of sets of the photoconductor and the writing unit.   The image forming apparatus according to claim 11, wherein the writing unit is an LEDA (Light Emitting Diode Array).

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