A control and implementation system of a laser printer based on an SLCD interface and a method thereof

Abstract

The application provides a control and implementation system and method of a laser printer based on an SLCD interface, and the system at least comprises a laser printing control system as a master Soc, a laser printing scanning unit and an upper computer, all controls of the laser printing scanning unit are completed by the Soc; the application is based on a general heterogeneous CPU Soc, a common SLCD interface is used, and the control of the laser printer control system and the laser scanning module is implemented. The implementation method is that only one general Soc is used to complete the whole laser printer control system, so that the selection threshold of the laser printer control chip is reduced, and meanwhile, no additional FPGA assistance is needed, and the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of printer technology, and specifically relates to a control and implementation system and method for a laser printer based on an SLCD interface. Background Technology

[0002] In existing technologies, laser printers utilize electro-imaging transfer technology, using a laser beam to quickly "project" digital graphics or documents onto a photosensitive drum. Then, toner is electrostatically adsorbed to transfer the image to paper, and heat is used to fix the image. In this process, the laser scanning unit and the laser printer's control system are key technologies. The laser scanning unit includes core components such as a laser generator, lens assembly, multi-mirror motor, and toner cartridge.

[0003] like Figure 1 As shown in patent CN1184540C, "Method and Apparatus for Compensating Print Output Density Shift of Image Forming Apparatus", and as in... Figure 2 The print engine module shown in patent CN1194405A, "Method and Apparatus for Automatically Determining the Type of Printhead Installed in a Laser Printer," uses a dedicated ASIC for laser raster data output and signal processing. Examples of such chips include the Qbit63xx. Alternatively, an additional FPGA can be used to implement the dedicated ASIC functions to control the laser scanning module.

[0004] However, the dedicated ASICs mentioned above implicitly limit the range of chips that can be selected for laser printer control. Only dedicated printer control chips can be used for printer control. If an FPGA is used to control the printing and scanning module, the cost will increase accordingly.

[0005] In addition, commonly used technical terms include:

[0006] 1. LSU printer: Laser printer.

[0007] 2. Raster data: Data from the laser generator, which is obtained by converting JBIG, PDF and other image data through the image data processing module.

[0008] 3. Toner cartridge / photosensitive drum: This is a photosensitive device with the characteristic of conducting light. Before scanning exposure, the photoconductive coating on its surface is uniformly charged by a charging roller. When a laser beam scans the photosensitive drum in a dot matrix pattern, the scanned dots become conductive due to exposure, and the charge is rapidly released to ground from the conductive base. Unexposed dots retain their original charge. Through exposure, an electrostatic latent image is formed. When the drum rotates to the position of the toner-carrying magnetic roller, it attracts toner, forming a toner image.

[0009] 4. SLCD Interface: A control interface for LCD displays, conforming to the MIPIDBI protocol definition.

[0010] 5. TE: This is a signal of the MIPIDBI protocol, used as an input signal for the SLCD interface. The SLCD data signal will only be output when the TE signal is valid.

[0011] 6. PWM: Pulse Width Modulation, an analog control method that modulates the bias of the base of a transistor or the gate of a MOSFET according to the change of the corresponding load, thereby changing the conduction time of the transistor or MOSFET and thus changing the output of the switching power supply.

[0012] 7. DDR: Double Data Rate, DDR SDRAM = Double Data Rate Synchronous Dynamic Random Access Memory, commonly referred to as DDR. Summary of the Invention

[0013] To address the aforementioned issues, the purpose of this application is to: implement a laser printer control system and control of the laser scanning module based on a general-purpose heterogeneous CPU system-on-a-chip (SoC) and using a common SLCD interface.

[0014] Specifically, the present invention provides a control and implementation system for a laser printer based on an SLCD interface, the system comprising at least:

[0015] The laser printing control system consists of a main control system-on-a-chip (SoC), a laser printing scanning unit, and a host computer. The SoC controls all aspects of the laser printing scanning unit.

[0016] The laser printing control system includes:

[0017] A large-core CPU with an image processing module;

[0018] A small-core CPU containing a real-time control module connected to a large-core CPU;

[0019] The input interface for communication with the host computer;

[0020] The SLCD of the output interfaces Data0 and Data1, which are connected to the laser generator data interface, and the input interface TE, which is connected to the detector HSYC signal;

[0021] In addition, a pulse width modulation (PWM) controller and double data rate memory (DDR);

[0022] The large-core CPU, small-core CPU, input interface, SLCD, PWM and DDR inside the laser printing control system are interconnected through a system bus.

[0023] The laser printing scanning unit includes a laser scanning unit (LSU) and a photosensitive drum. The LSU includes: laser generator 0 and laser generator 2, a motor, an anti-aliasing synchronization signal, and a line HSYNC detector.

[0024] Further includes:

[0025] The input interface communicates with the host computer, which sends the graphic data to be printed and commands.

[0026] The SLCD interface is connected to Data0 and laser generator 0, and connected to Data1 and laser generator 2, respectively outputting the required raster data;

[0027] The HSYNC detector is connected to the SLCD TE interface and the small-core CPU; the PWM independently controls the motor and the periodic signal, i.e., the shadow cancellation signal; the large-core CPU completes the complex communication and image processing functions with the host computer; together with the small-core CPU, it responds in real time to complete the logic control of various modules including SLCD and PWM.

[0028] In the system, Data0 alone can control one laser data output, while Data0 and Data1 can be used simultaneously to control two laser data outputs. This configuration can be flexibly selected according to the actual laser head situation.

[0029] The SLCD TE serves as an external input signal, automatically starting and stopping the laser grating data output according to the HSYNC transformation.

[0030] The laser printing scanning unit uniformly scans the photosensitive drum with a laser.

[0031] This application also relates to a control and implementation method for a laser printer based on an SLCD interface, the method being applicable to any of the aforementioned systems, and further comprising:

[0032] S1, Input: Input from the input interface, which includes Ethernet, USB, and WIFI interfaces;

[0033] S2, the input module receives data and start commands;

[0034] Accepts image data to be printed, including PDF, PNG, and JBIG formats.

[0035] S3, the image processing module processes N rows of data; this is just the preparation of the first N rows of data.

[0036] The received data is processed by the large-core CPU and converted into grating data for laser dot matrix output by the image processing module, and temporarily stored in DDR;

[0037] S4, activate SLCD, SLCD enters standby output state;

[0038] Since the HSYNC trigger signal is invalid at this time, that is, HSYC is emitted by the detector of the scanning unit. When the laser is in a non-effective printing area, the signal is low and invalid. The main controller does not output printing data. Therefore, the SLCD TE input signal is invalid, so the SLCDData line data is not output and the SLCD controller is in the standby output state.

[0039] S5 activates PWM, and the LSU motor starts working.

[0040] The small-core CPU initiates PWM to control the LSU motor module to start working; after the motor is working stably, it sends a READY signal.

[0041] S6, the small-core CPU receives the READY signal;

[0042] S7, the small-core CPU initiates the image cancellation signal output. The image cancellation signal changes periodically, and at this time the image cancellation signal is effective, and the laser will not produce a latent image on the photosensitive drum; that is:

[0043] Upon receiving the READY signal, the small-core CPU initiates the output of the shadow cancellation signal. The shadow cancellation signal is output periodically. When it is in a high-level period, the shadow cancellation signal is valid and there is no laser signal.

[0044] S8, HSYNC signal valid, SLCD data output;

[0045] After the READEY signal becomes valid, the periodic signal of the shadow removal signal changes to a low level, and the laser signal is emitted. When the laser reaches the effective position, the HSYNC signal becomes valid.

[0046] When the SLCD control signal TE is valid, HSYNC is valid. SLCD automatically outputs the prepared data and continues to steps S9 and S10 respectively.

[0047] S9, the laser scanning module, i.e., the laser printing scanning unit, is in operation;

[0048] The laser generator uniformly scans the grating data onto the photosensitive drum. As the scanning and the rotation of the photosensitive drum occur, an effective electrostatic latent image is formed on the selenium drum.

[0049] The photosensitive drum with electrostatic latent image rotates to the position of the magnetic roller carrying toner, attracting toner with opposite charge;

[0050] After one line of data scanning is completed, the HSYNC signal becomes invalid;

[0051] S10, determine whether the small core CPU received an invalid HSYNC interrupt; this is the determination of whether the small core received an HSYNC interrupt.

[0052] When HSYNC is invalid, the small core CPU will receive an interrupt. The small core CPU responds to its HSYNC invalid interrupt by executing the interrupt response function, i.e., proceeding to step S11; otherwise, repeat S10.

[0053] S11, the small-core CPU responds to its HSYNC invalid interrupt. First, it updates the motor speed, i.e., adjusts the LSU motor speed; second, it notifies the large-core CPU to prepare the raster data for the next print.

[0054] S12, determine whether all data to be printed has been output. If it has, end; otherwise, proceed to step S13.

[0055] S13, trigger the image processing module to process N lines of data. Assuming that all data to be printed is M lines, and the printing process is carried out in blocks, with each block consisting of N lines, the entire data processing process needs to be executed M / N-1 times. Return to step S8 until M / N times are completed, that is, until step S12 when all data is output.

[0056] Step S8 further includes:

[0057] The laser generator starts working after the LSU receives a valid READEY signal;

[0058] The cancellation signal changes periodically, at which point it automatically becomes invalid;

[0059] When the laser reaches the effective position, the HSYNC signal becomes effective, the TE signal input to the SLCD becomes effective, the SLCD reads the raster data from the DDR and outputs it to the LSU laser generator from the Data line.

[0060] Therefore, the advantage of this application lies in proposing a general-purpose SoC based on heterogeneous CPUs, using the common SLCD interface, and leveraging its TE signal characteristics to implement the laser printer scanning module and laser printer control system. This implementation method uses only a single general-purpose SoC to complete the entire laser printer control system, which not only lowers the selection threshold for laser printer control chips but also eliminates the need for additional FPGA assistance, thus reducing costs. Attached Figure Description

[0061] The accompanying drawings, which are provided to further illustrate the invention and form part of this application, are not intended to limit the scope of the invention.

[0062] Figure 1 This is a schematic diagram of a printing engine, one of the existing technologies.

[0063] Figure 2 This is a schematic diagram of a printing engine based on existing technology.

[0064] Figure 3 This is a schematic diagram of the system structure of this application.

[0065] Figure 4 This is a flowchart illustrating the method described in this application.

[0066] Figure 5 This is a schematic diagram of the hardware implementation of the technical solution according to this application. Detailed Implementation

[0067] To better understand the technical content and advantages of the present invention, the present invention will now be described in further detail with reference to the accompanying drawings.

[0068] This invention proposes a control and implementation system and method for a laser printer based on an SLCD interface, such as... Figure 3 As shown, the system interface implementation of the present invention includes at least: a laser printing control system is a main control system-on-a-chip (SoC), a laser printing scanning unit, and a host computer, wherein the SoC performs all control over the laser printing scanning unit;

[0069] The laser printing control system includes:

[0070] A large-core CPU with an image processing module;

[0071] A small-core CPU containing a real-time control module connected to a large-core CPU;

[0072] The input interface for communication with the host computer;

[0073] The SLCD of the output interfaces Data0 and Data1, which are connected to the laser generator data interface, and the input interface TE, which is connected to the detector HSYC signal;

[0074] In addition to pulse width modulation (PWM) and double data rate memory (DDR);

[0075] The large-core CPU, small-core CPU, input interface, SLCD, PWM and DDR inside the laser printing control system are connected through a system bus;

[0076] The laser printing scanning unit includes a laser scanning unit (LSU) and a photosensitive drum. The LSU includes: laser generator 0 and laser generator 2, a motor, an anti-aliasing synchronization signal, and a line HSYNC detector.

[0077] Further includes:

[0078] The input interface communicates with the host computer, which sends the graphic data to be printed and commands.

[0079] The SLCD interface is connected to Data0 and laser generator 0, and connected to Data1 and laser generator 2 to output the required grating data respectively. Data0 alone can control one laser data output, while Data0 and Data1 can be used simultaneously to control two laser data outputs. This configuration can be flexibly selected according to the actual laser head situation.

[0080] The HSYNC detector is connected to the SLCD TE interface and to the small core CPU; the SLCD TE serves as an external input signal, automatically starting and stopping the laser grating data output according to the changes in the HSYNC of the laser scanning module.

[0081] The PWM independently controls the motor and the periodic signal, i.e., the shadow cancellation signal; the large-core CPU completes the complex communication and image processing functions with the host computer; and together with the small-core CPU, it responds in real time to complete the logic control of various modules including SLCD and PWM.

[0082] Furthermore, such as Figure 4 As shown, the flow of the method applicable to the above system is as follows:

[0083] S1, Input: Input from the input interface, which includes Ethernet, USB, and WIFI interfaces;

[0084] S2, the input module receives data and start commands;

[0085] Accepts image data to be printed, including PDF, PNG, and JBIG formats.

[0086] S3, the image processing module processes N rows of data; step S3 is only the preparation of the first N rows of data; the received data is processed by the large-core CPU, and converted into grating data for laser dot matrix output by the image processing module, and temporarily stored in DDR;

[0087] S4, activate SLCD, SLCD enters standby output state;

[0088] Since the HSYNC trigger signal is invalid at this time, that is, HSYC is emitted by the detector of the scanning unit. When the laser is in a non-effective printing area, the signal is low and invalid. The main controller does not output printing data. Therefore, the SLCD TE input signal is invalid, so the SLCDData line data is not output and the SLCD controller is in the standby output state.

[0089] S5 activates PWM, and the LSU motor starts working.

[0090] The small-core CPU initiates PWM to control the LSU motor module to start working; after the motor is working stably, it sends a READY signal.

[0091] S6, the small-core CPU receives the READY signal;

[0092] S7, the small-core CPU initiates the image cancellation signal output. The image cancellation signal changes periodically, and at this time the image cancellation signal is effective, and the laser will not produce a latent image on the photosensitive drum; that is:

[0093] Upon receiving the READY signal, the small-core CPU initiates the output of the shadow cancellation signal. The shadow cancellation signal is output periodically. When it is in a high-level period, the shadow cancellation signal is valid and there is no laser signal.

[0094] S8, HSYNC signal valid, SLCD data output;

[0095] After the READEY signal becomes valid, the periodic signal of the shadow removal signal changes to a low level, and the laser signal is emitted. When the laser reaches the effective position, the HSYNC signal becomes valid.

[0096] When the SLCD control signal TE is valid, HSYNC is valid. The SLCD automatically outputs the prepared data and continues to proceed to steps S9 and S10. In implementation, this is done in parallel. The SLCD outputs data to the laser generator. At the same time, the small-core CPU is in an interrupt state that can respond to the HSYNC signal change. In operation, the laser signal usually continues to be emitted after step S9 is completed until it goes out of the valid range and the HSYNC signal becomes invalid. Only then will the HSYNC interrupt handler of the small-core CPU be triggered to complete the work of S10.

[0097] Step S8 further includes:

[0098] The laser generator starts working after the LSU receives a valid READEY signal;

[0099] The cancellation signal changes periodically, at which point it automatically becomes invalid;

[0100] When the laser reaches the effective position, the HSYNC signal is valid, the TE signal input to the SLCD is valid, the SLCD reads the raster data from the DDR and outputs it to the LSU laser generator from the Data line;

[0101] S9, the laser scanning module, i.e., the laser printing scanning unit, is in operation;

[0102] The laser generator uniformly scans the grating data onto the photosensitive drum. As the scanning and the rotation of the photosensitive drum occur, an effective electrostatic latent image is formed on the selenium drum.

[0103] The photosensitive drum with electrostatic latent image rotates to the position of the magnetic roller carrying toner, attracting toner with opposite charge;

[0104] After one line of data scanning is completed, the HSYNC signal becomes invalid;

[0105] S10, determine whether the small core CPU received an invalid HSYNC interrupt; this is the determination of whether the small core received an HSYNC interrupt.

[0106] When HSYNC is invalid, the small core CPU will receive an interrupt. The small core CPU responds to its HSYNC invalid interrupt by executing the interrupt response function, i.e., proceeding to step S11; otherwise, repeat S10.

[0107] S11, the small-core CPU responds to its HSYNC invalid interrupt. First, it updates the motor speed, i.e., adjusts the LSU motor speed; second, it notifies the large-core CPU to prepare the raster data for the next print.

[0108] S12, determine whether all data to be printed has been output. If it has, end; otherwise, proceed to step S13.

[0109] S13, trigger the image processing module to process N lines of data. Assuming that all data to be printed is M lines, and the printing process is carried out in blocks, with each block consisting of N lines, the entire data processing process needs to be executed M / N-1 times. Return to step S8 until M / N times are completed, that is, until step S12 when all data is output.

[0110] The above outlines the specific implementation steps and the overall design scheme. Following this scheme, the following can be achieved: Figure 5 The hardware implementation diagram shown can be followed by the software implementation as described above. Currently, this solution can be used for Junzheng 33PPM and 22PPM printing products.

[0111] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0112] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0113] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the embodiments of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control and implementation system for a laser printer based on an SLCD interface, characterized in that, The system includes at least: a laser printing control system, a main control system-on-a-chip (SoC), a laser printing scanning unit, and a host computer, wherein the SoC performs all control over the laser printing scanning unit; the laser printing control system includes: A large-core CPU with an image processing module; A small-core CPU containing a real-time control module connected to a large-core CPU; The input interface for communication with the host computer; The SLCD of the output interfaces Data0 and Data1, which are connected to the laser generator data interface, and the input interface TE, which is connected to the detector HSYC signal; In addition, a pulse width modulation (PWM) controller and double data rate memory (DDR); The large-core CPU, small-core CPU, input interface, SLCD, PWM and DDR inside the laser printing control system are interconnected through a system bus. The laser printing scanning unit includes a laser scanning unit (LSU) and a photosensitive drum. The LSU includes: laser generator 0 and laser generator 2, a motor, an anti-aliasing synchronization signal, and a line HSYNC detector. Further includes: The input interface communicates with the host computer, which sends the graphic data to be printed and commands. The SLCD interface is connected to Data0 and laser generator 0, and connected to Data1 and laser generator 2, respectively outputting the required raster data; The HSYNC detector is connected to the SLCD TE interface and the small-core CPU; the PWM independently controls the motor and the periodic signal, i.e., the shadow cancellation signal; the large-core CPU completes the complex communication and image processing functions with the host computer; together with the small-core CPU, it responds in real time to complete the logic control of various modules including SLCD and PWM.

2. The control and implementation system for a laser printer based on an SLCD interface according to claim 1, characterized in that, In the system, Data0 alone can control one laser data output, while Data0 and Data1 can be used simultaneously to control two laser data outputs. This configuration can be flexibly selected according to the actual laser head situation.

3. The control and implementation system for a laser printer based on an SLCD interface according to claim 1, characterized in that, The SLCD TE serves as an external input signal, automatically starting and stopping the laser grating data output according to the HSYNC transformation.

4. The control and implementation system for a laser printer based on an SLCD interface according to claim 1, characterized in that, The laser printing scanning unit uniformly scans the photosensitive drum with a laser.

5. A control and implementation method for a laser printer based on an SLCD interface, characterized in that, The method is applicable to any of the systems described in claims 1-4, and further includes: S1, Input: Input from the input interface, which includes Ethernet, USB, and WIFI interfaces; S2, the input module receives data and start commands; Accepts image data to be printed, including PDF, PNG, and JBIG formats. S3, the image processing module processes N rows of data; this is just the preparation of the first N rows of data. The received data is processed by the large-core CPU and converted into grating data for laser dot matrix output by the image processing module, and temporarily stored in DDR; S4, activate SLCD, SLCD enters standby output state; Since the HSYNC trigger signal is invalid at this time, that is, HSYC is emitted by the detector of the scanning unit. When the laser is in a non-effective printing area, the signal is low and invalid. The main controller does not output printing data. Therefore, the SLCD TE input signal is invalid, so the SLCDData line data is not output and the SLCD controller is in the standby output state. S5 activates PWM, and the LSU motor starts working. The small-core CPU initiates PWM to control the LSU motor module to start working; after the motor is working stably, it sends a READY signal. S6, the small-core CPU receives the READY signal; S7, the small-core CPU initiates the image cancellation signal output. The image cancellation signal changes periodically, and at this time the image cancellation signal is effective, and the laser will not produce a latent image on the photosensitive drum; that is: Upon receiving the READY signal, the small-core CPU initiates the output of the shadow cancellation signal. The shadow cancellation signal is output periodically. When it is in a high-level period, the shadow cancellation signal is valid and there is no laser signal. S8, HSYNC signal valid, SLCD data output; After the READEY signal becomes valid, the periodic signal of the shadow removal signal changes to a low level, and the laser signal is emitted. When the laser reaches the effective position, the HSYNC signal becomes valid. When the SLCD control signal TE is valid, HSYNC is valid. SLCD automatically outputs the prepared data and continues to steps S9 and S10 respectively. S9, the laser scanning module, i.e., the laser printing scanning unit, is in operation; The laser generator uniformly scans the grating data onto the photosensitive drum. As the scanning and the rotation of the photosensitive drum occur, an effective electrostatic latent image is formed on the selenium drum. The photosensitive drum with electrostatic latent image rotates to the position of the magnetic roller carrying toner, attracting toner with opposite charge; After one line of data scanning is completed, the HSYNC signal becomes invalid; S10, determine whether the small core CPU received an invalid HSYNC interrupt; this is the determination of whether the small core received an HSYNC interrupt. When HSYNC is invalid, the small core CPU will receive an interrupt. The small core CPU responds to its HSYNC invalid interrupt by executing the interrupt response function, i.e., proceeding to step S11; otherwise, repeat S10. S11, the small-core CPU responds to its HSYNC invalid interrupt. First, it updates the motor speed, i.e., adjusts the LSU motor speed; second, it notifies the large-core CPU to prepare the raster data for the next print. S12, determine whether all data to be printed has been output. If it has, end; otherwise, proceed to step S13. S13, trigger the image processing module to process N lines of data. Assuming that all data to be printed is M lines, and the printing process is carried out in blocks, with each block consisting of N lines, the entire data processing process needs to be executed M / N-1 times. Return to step S8 until M / N times are completed, that is, until step S12 when all data is output.

6. The control and implementation method for a laser printer based on an SLCD interface according to claim 5, characterized in that, Step S8 further includes: The laser generator starts working after the LSU receives a valid READEY signal; The cancellation signal changes periodically, at which point it automatically becomes invalid; When the laser reaches the effective position, the HSYNC signal becomes effective, the TE signal input to the SLCD becomes effective, the SLCD reads the raster data from the DDR and outputs it to the LSU laser generator from the Data line.

Images