Printing head and printer

Abstract

The invention provides a printing head and a printer. The printing head comprises a light-emitting array and a driving chip. The light-emitting array comprises a plurality of light-emitting units, and each light-emitting unit corresponds to a photosensitive point on the printer; the driving chip is used for dividing one-time light sensing time of the light sensing point into a plurality of time periods and controlling the light emitting unit to emit light according to the brightness level corresponding to each time period in each time period, so that the light sensing point senses light in each time period; different time periods correspond to different brightness levels. The photosensitive time is divided into a plurality of time periods, and the light emitting unit is controlled to emit light at different brightness levels in different time periods, so that the light intensity accumulated and received by the photosensitive points reaches the target brightness, the gray scale expression capability of the printer is improved, multi-level gray scale control is realized, and the advantage of improving the printing quality is achieved.

Description

Technical Field

[0001] This application relates to the field of printing equipment technology, specifically to a printhead and a printer. Background Technology

[0002] With the continuous development of technology, printers are increasingly widely used in offices and daily life. Among the many types of printers, those using light-emitting diode (LED) printheads have attracted market attention due to their advantages such as fast printing speed and small size. However, existing printing technologies still have many shortcomings: inkjet printing technology, while capable of diverse color output, has a relatively slow printing speed, is prone to printhead clogging, and has high ink costs; laser printing technology, while offering faster printing speeds, has higher equipment costs, larger size, and suffers from issues such as insufficient color reproduction accuracy in color printing.

[0003] While LED printhead technology combines some advantages of traditional printing technologies, its driving scheme still has significant drawbacks. For example, existing LED driving schemes typically use global current control to regulate the maximum brightness of the LEDs, and pulse width modulation to independently control the brightness of each LED in each channel. During printer operation, because the photosensitive drum rotates continuously, this approach makes it difficult to precisely control the LED's illumination position on the drum, thus limiting the printer's grayscale performance and hindering multi-level grayscale control, ultimately impacting print quality improvement. Summary of the Invention

[0004] The purpose of the embodiments of this application is to provide a printhead and printer that have the advantages of improving the grayscale performance of the printer, realizing multi-level grayscale control, and thus improving print quality.

[0005] Embodiments of this application provide a printhead, comprising:

[0006] A light-emitting array, the light-emitting array comprising a plurality of light-emitting units, each light-emitting unit corresponding to a photosensitive point on a printer;

[0007] The driving chip is used to divide the photosensitive time of the photosensitive point into multiple time periods, and control the light-emitting unit to emit light according to the brightness level corresponding to each time period, so that the photosensitive point is photosensitive in each time period; wherein the brightness level corresponding to different time periods is different.

[0008] This application embodiment also provides a printer applied to the above-described printhead and photosensitive drum, wherein the photosensitive drum includes a plurality of photosensitive dots, each photosensitive dot being configured corresponding to one or more light-emitting units of the printhead.

[0009] In summary, the printhead and printer provided in this application improve the printer's grayscale performance by dividing the photosensitive time into multiple time periods and controlling the light-emitting units to emit light at different brightness levels during these time periods. This allows the cumulative light intensity received by the photosensitive points to reach the target brightness, thereby achieving multi-level grayscale control and improving print quality. Specifically, the light-emitting array includes multiple light-emitting units, each corresponding to a photosensitive point on the printer. The driver chip divides the photosensitive time of a single photosensitive point into multiple time periods and controls the light-emitting units to emit light at the brightness level corresponding to each time period, allowing the photosensitive point to be photosensitive in each time period. The brightness levels corresponding to different time periods are different. This achieves multimodal data fusion, improving the comprehensiveness of environmental perception. The dynamic weighting factor enhances the adaptability of parameter adjustment, enabling stable brightness, color, and response speed in complex environments while reducing overall energy consumption. Attached Figure Description

[0010] The present application will be further described below with reference to the accompanying drawings. It should be noted that the accompanying drawings described below are merely for explaining some embodiments of the present application. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0011] Figure 1 A schematic diagram of a printhead provided for an embodiment of this application.

[0012] Figure 2 This is a schematic diagram of a light-emitting array provided for an embodiment of this application.

[0013] Figure 3 This is a schematic diagram of the row driver and segment driver used in this application to drive the LED light-emitting unit.

[0014] Figure 4 This is a schematic diagram illustrating one application scenario of the printhead provided in this application.

[0015] Figure 5 A schematic diagram of the brightness levels provided in this application.

[0016] Figure 6 This is a schematic diagram showing the illumination at different brightness levels during different time periods, as provided in this application.

[0017] Figure 7 This is a schematic diagram illustrating another application scenario of the printhead provided in this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0019] In the description of this application, the terms "first," "second," and similar words do not indicate any order, quantity, or importance, but are merely used to distinguish different technical features. The terms "multiple" and similar words indicate two or more unless otherwise expressly defined. Embodiments of this application can be combined with each other.

[0020] This application provides a printhead, which includes, but is not limited to, the following embodiments and combinations thereof.

[0021] In one embodiment, Figure 1 A schematic diagram of the printhead provided for an embodiment of this application, as shown below. Figure 1 As shown, the printhead 100 includes a light-emitting array 101 and a driver chip 102; wherein, the light-emitting array 101 includes multiple light-emitting units, each light-emitting unit corresponding to a photosensitive point on the printer.

[0022] The driver chip 102 is used to divide the single light-sensing time of the photosensitive point into multiple time periods, and control the light-emitting unit to emit light according to the brightness level corresponding to each time period, so that the photosensitive point can be light-sensing in each time period; wherein, the brightness level corresponding to different time periods is different.

[0023] It should be noted that the light-emitting array 101 can be a planar structure composed of multiple independently controllable light sources. For example, it can be implemented using a matrix arrangement of micro LEDs, with each LED corresponding to an imaging point on the surface of the photosensitive drum. The driving chip 102 can be an integrated circuit with timing control capabilities. For example, it can be implemented using an ASIC chip with a time-division control module, used to precisely divide the exposure cycle and allocate brightness parameters. Time period division refers to decomposing the continuous exposure process into several discrete exposure units. For example, it can be implemented using a clock signal frequency division method, with each time period corresponding to a specific brightness adjustment command. Brightness level refers to the working intensity level of the light-emitting unit in different time periods. For example, it can be implemented using a current step adjustment method, producing differentiated light intensity by changing the driving current value.

[0024] Specifically, the driver chip 102 divides the complete photosensitivity cycle into several sub-segments of fixed or variable length. Within each sub-segment, the light-emitting unit emits light according to preset brightness parameters, and different current driving values ​​are used in different time periods.

[0025] As an example, the light-emitting array 101 can be an LED bar; the driver chip 102 can be a driver IC; the light-emitting unit can be an LED light-emitting unit, or simply LED; the driver chip 102 can include a row driver and a segment driver, wherein the row driver can be referred to as a COM driver; the segment driver can be referred to as a SEG driver; the COM driver can be connected to the light-emitting array 101 through multiple power lines, which can be referred to as COM1, COM2, COM3...; the SEG driver can be connected to the light-emitting array 101 through multiple control lines, which can be referred to as SEG1, SEG2, SEG3...

[0026] This application overcomes the grayscale limitation by employing a multi-time-segment overlay mechanism. This allows for multi-level intensity regulation within a fixed exposure cycle, solving the grayscale control problem in dynamic imaging. This method ensures the accuracy of the light spot position, improves image tonal representation, and avoids complex timing control adjustments, maintaining the structural stability and cost controllability of the printing system.

[0027] In one embodiment, the driver chip 102 is further configured to send a first signal to the light-emitting units in each row of the light-emitting array 101 and a second signal to the light-emitting units in each column; the first signal is used to control the conduction state of the light-emitting units in each row; and the second signal is used to control the brightness level of the light-emitting units in each column.

[0028] The first signal can be a logic level signal used to control row selection. For example, it can be implemented by switching between high and low levels, such as a high level corresponding to the on state and a low level corresponding to the off state, and row addressing is achieved by scanning row by row. The second signal can be an electrical signal used to adjust the light intensity. For example, it can be implemented by a variable current or voltage signal. For example, by adjusting the current value, the brightness level of the light-emitting unit is changed, thereby achieving independent brightness control of the light-emitting units in different columns of the same row.

[0029] Specifically, during a row scan cycle, when a row is activated by a high-level signal, the anodes of all light-emitting units in that row are in a conducting state. At this time, the segment driver outputs a corresponding current signal to the cathodes of each column's light-emitting units based on preset grayscale data. For example, a larger current is applied to columns requiring high brightness output, while a smaller current is applied to columns requiring low brightness. By coordinating the timing of the row and column signals, each light-emitting unit can operate at a specified brightness level within the selected time period.

[0030] As an example, Figure 2 This is a schematic diagram of a light-emitting array provided for an embodiment of this application. (See diagram below.) Figure 2As shown, COM1, COM2, COM3, and COM4 send a first signal to the light-emitting unit in the corresponding row of the light-emitting array 101, and SEG1, SEG2, SEG3, and SEG4 send a second signal to the light-emitting unit in the corresponding column of the light-emitting array 101.

[0031] This application achieves multi-level grayscale output by independently controlling the driving current of each column of light-emitting units, enabling light-emitting units at different positions within the same row to exhibit differentiated brightness. This solves the technical deficiency of traditional LED printheads in achieving multi-level grayscale control within the same row, allowing the photosensitive drum to obtain precise light intensity distribution through time-division and zone control during rotation, thereby improving the resolution and tonal representation of the printed image.

[0032] In one embodiment, the driver chip 102 includes a row driver and a segment driver; the first signal includes a high-level signal and a low-level signal; and the second signal includes an electrical signal.

[0033] A row driver is used to respond to control commands by providing a high-level signal to the LED unit of the selected row and a low-level signal to the LED unit of the unselected row.

[0034] A segment driver is used to control the high-level signal light-emitting unit to output an electrical signal within a selected time period based on preset grayscale data.

[0035] The row driver can be a circuit module used to control the row selection of the light-emitting unit. For example, it can be implemented using a shift register or a decoder. Its function is to select or turn off the light-emitting unit of a specific row by outputting a high-level or low-level signal.

[0036] The segment driver can be a circuit module used to control the brightness level of the light-emitting unit. For example, it can be implemented using a digital-to-analog converter or a current source array. Its function is to adjust the electrical signal parameters according to the grayscale data, thereby controlling the light intensity of the light-emitting unit in different time periods.

[0037] The high-level signal can be a voltage signal used to turn on the light-emitting unit. For example, it can be implemented using a fixed voltage source or an adjustable power supply, and its function is to provide the conduction condition for the selected row.

[0038] A low-level signal can be a voltage signal used to turn off the light-emitting unit. For example, it can be implemented using a ground or negative voltage source, and its function is to provide a cutoff condition for unselected rows.

[0039] The electrical signal can be a driving signal used to adjust the brightness of the light-emitting unit. For example, it can be implemented using pulsed current or variable voltage waveforms. Its function is to change the instantaneous light intensity of the light-emitting unit by adjusting the signal parameters.

[0040] Grayscale data can be digital information used to define the target brightness level within different time periods. For example, it can be implemented using binary encoding or multi-level quantization data, and its function is to provide a basis for brightness adjustment for segment drivers.

[0041] Specifically, after receiving a control command, the row driver selects the light-emitting unit in the target row by outputting a high-level signal, while simultaneously turning off the light-emitting units in other rows by outputting a low-level signal. The segment driver generates a corresponding electrical signal based on preset grayscale data and applies the electrical signal to the selected light-emitting units in the selected row within a selected time period. Through the coordinated operation of the row driver and the segment driver, the light-emitting units in the same row can emit light at different brightness levels within different time periods, thereby achieving multi-level grayscale sensing of the photosensitive point.

[0042] As an example, a line driver can be referred to as a COM driver; a segment driver can be referred to as a SEG driver; such as Figure 3 As shown, Figure 3 This is a schematic diagram of the row driver and segment driver used in this application to drive the LED light-emitting unit.

[0043] This application achieves multi-grayscale output by controlling different brightness levels in a time-division manner while maintaining a fixed pulse width, utilizing the division of labor between the line driver and the segment driver. Furthermore, by separating the functions of the line driver and the segment driver, this application reduces circuit complexity and improves control precision. Thus, this application achieves precise time-division control of the brightness levels of the light-emitting unit, solving the problem that traditional LED printheads cannot output multiple grayscale levels. The independent operation of the line driver and the segment driver avoids signal crosstalk and simplifies the driving circuit structure. In addition, the brightness adjustment method based on grayscale data can flexibly adapt to different printing needs, improving print resolution and image quality.

[0044] In one embodiment, the printhead 100 further includes multiple power lines and multiple control lines, wherein,

[0045] Multiple power lines, one end of each power line is connected to the anode of a row of light-emitting units, and the other end is connected to the row driver.

[0046] Multiple control lines, one end of each control line is connected to the cathode of a row of light-emitting units, and the other end is connected to the segment driver.

[0047] The multiple power lines can be conductive lines used to provide driving voltage to the light-emitting units. For example, they can be made of copper or silver, and their cross-sectional area can be designed based on current carrying requirements. This structure allows the row driver to independently control the conduction state of each row of light-emitting units via the power lines.

[0048] Multiple control lines can serve as signal transmission lines for adjusting the brightness of the light-emitting units; for example, they can be implemented using flexible circuit boards or thin-film conductors. This structure allows the segment driver to independently adjust the operating current of each column of light-emitting units at different time periods via the control lines, thereby achieving graded brightness control.

[0049] Specifically, the power line transmits the level signal output by the row driver to the anode of the corresponding row's light-emitting unit. When a row is selected, its anode receives a high-level signal, putting that row into a conducting state. The control line transmits the grayscale control signal generated by the segment driver to the cathode of the corresponding column's light-emitting unit. By adjusting the cathode voltage, the current flowing through the light-emitting unit is changed, thereby controlling the light intensity. The coordinated operation of the row driver and segment driver enables each light-emitting unit to emit light precisely according to preset grayscale data during conduction.

[0050] As an example, multiple power lines can be labeled COM1, COM2, COM3...; multiple control lines can be labeled SEG1, SEG2, SEG3...; this information can be combined with... Figure 1 and Figure 2 To understand.

[0051] This application achieves physical isolation between row gating and column dimming by setting up multiple independent power and control lines, avoiding signal crosstalk problems, and providing an independent and controllable current path for each light-emitting unit. In this way, this application ensures that each light-emitting unit is controlled only by the corresponding row and column drive signals during gating, eliminating electrical interference between adjacent units. This ensures that the light intensity received by each photosensitive point on the photosensitive drum is strictly matched with the preset grayscale data, thereby achieving accurate reproduction of multiple grayscale levels within a fixed exposure time.

[0052] In one embodiment, the plurality of power lines include a first power line connected to the odd-numbered rows of light-emitting units and a second power line connected to the even-numbered rows of light-emitting units; one of the first power line and the second power line is used to provide the high-level signal, and the other is used to provide the low-level signal.

[0053] The first power line can be a conductive line providing driving voltage to the odd-numbered rows of light-emitting units. For example, it can be implemented using copper or alloy wires, and its function is to establish an independent power supply circuit for the odd-numbered rows of units. The second power line can be a conductive line providing driving voltage to the even-numbered rows of light-emitting units. For example, it can be implemented using parallel wiring of the same material as the first power line, and its function is to construct an isolated power supply channel for the even-numbered rows of units. The high-level signal can be a voltage signal that enables the light-emitting units to conduct, for example, it can be implemented using a 5V or 3.3V DC voltage, and its function is to provide operating energy to the selected light-emitting units. The low-level signal can be a voltage signal that puts the light-emitting units into the off state, for example, it can be implemented using 0V or a negative bias voltage, and its function is to provide electrical isolation to the unselected units.

[0054] Specifically, under the control of the driver chip, when the row driver selects an odd-numbered row, the first power line is configured to output a high-level signal, while the second power line automatically switches to a low-level signal. This alternating power supply method ensures electrical isolation between the light-emitting units of adjacent rows, avoiding crosstalk between rows. For example, during printhead operation, if the light-emitting unit of the third row is activated, the first power line will remain high, while the second power line will remain low, ensuring that the units of the fourth, sixth, and other even-numbered rows are turned off. This time-sharing power supply mechanism effectively reduces the parasitic capacitance effect between adjacent rows, improving brightness control accuracy.

[0055] As an example, the first power line can be labeled COM1, COM3, ..., COM2N+1; the second power line can be labeled COM0, COM2, ..., COM2N. This content can be combined with... Figure 1 To understand.

[0056] This application achieves physical electrical isolation between adjacent rows by setting independent power lines for odd and even rows, fundamentally eliminating the impact of inter-row interference on grayscale accuracy. Compared to traditional single-line power supply solutions, this split power supply architecture can more precisely control the working state of each row of light-emitting units. Thus, this application effectively solves the signal crosstalk problem when multiple rows of light-emitting units are driven in parallel, enabling each light-emitting unit to accurately output a light signal at a preset brightness level within a selected time period. This split power supply method ensures the stability of multi-grayscale control signals, providing precisely controllable illumination intensity for the photosensitive drum, thereby significantly improving the tonal representation of printed images.

[0057] In one embodiment, multiple brightness levels are determined based on a target brightness; the two brightness levels corresponding to two adjacent time periods are in a multiple relationship; the light intensity received by the photosensitive point in the multiple time periods is greater than or equal to the light intensity corresponding to the target brightness.

[0058] Multiple brightness levels can be achieved by decomposing the target brightness into different levels of luminous intensity. For example, a binary weighting method can be used to divide the brightness levels, and the total light intensity can be precisely controlled by combining different brightness levels. The brightness levels corresponding to adjacent time periods can be multiples of each other, with the brightness level of each time period being an integer multiple of the previous time period. This can be achieved using a voltage divider circuit or a current mirror circuit, simplifying the calculation process for brightness level combinations. The total light intensity can be the sum of the light intensities received by the photosensitive point over all time periods. This can be achieved by measuring the cumulative light intensity of each time period using a photoelectric sensor, ensuring that the final total light intensity of the photosensitive point meets the expected target. For example, during the rotation of the photosensitive drum, the same photosensitive point receives light energy of different intensities sequentially, and the cumulative light energy of each time period forms the final effective exposure. For example, using brightness levels of 100%, 50%, 25%, and 12.5% ​​in four consecutive time periods, the total exposure can be equivalent to the energy value required for the target grayscale. By adjusting the brightness combination of each time period, multi-level grayscale control can be achieved without changing the total exposure time.

[0059] The target brightness can be determined based on the actual situation and is not a limitation here. As an example, the target brightness can be the brightness required by the user, such as the maximum required brightness Lmax.

[0060] Specifically, within one exposure cycle of the photosensitive point, the driver chip divides the total exposure time into several sub-time periods. Within each sub-time period, the light-emitting unit emits light according to a preset brightness multiple relationship; for example, the first time period uses 1x the reference brightness, and the second time period uses 2x the reference brightness. By superimposing and combining different brightness levels over time, the total light intensity of each time period ultimately reaches or exceeds the target brightness requirement. This time-division control method does not require changing the emission duration; precise light intensity adjustment can be achieved simply by adjusting the brightness multiple relationship.

[0061] As an example, taking a 16-grayscale LED printhead, based on the target brightness of the required maximum brightness Lmax, four global brightness levels are set: L1, L2, L3, and L4. The maximum brightness Lmax is approximately twice that of L1, L1 is approximately twice that of L2, L2 is approximately twice that of L3, and L3 is approximately twice that of L4. Each photosensitive point is exposed to light four times, with each exposure lasting a consistent time t1 = t2 = t3 = t4. The total light-sensitive energy received by a single photosensitive point from these four exposures is greater than or equal to the energy generated by the maximum brightness illumination. This content can be combined with... Figure 4 and Figure 5 To understand, Figure 4 A schematic diagram illustrating an application scenario of the printhead provided in this application; Figure 5 A schematic diagram of the brightness levels provided in this application.

[0062] This application achieves multi-level grayscale control by setting different brightness levels at different time intervals while maintaining a fixed exposure time, utilizing the principle of brightness superposition. Grayscale effects that require complex pulse-width modulation techniques in existing technologies can be achieved in this application with only simple brightness multiplier adjustments. Thus, this application effectively solves the technical problem of traditional LED printheads being unable to achieve multi-grayscale output. By setting different brightness levels at different time intervals, precise grayscale level control is achieved while ensuring the total exposure of the photosensitive points. This control method avoids the exposure position offset problem caused by traditional pulse-width modulation techniques, ensuring the sharpness of the printed image edges. At the same time, the design of the brightness level multiplier relationship simplifies the drive control logic and reduces hardware implementation complexity.

[0063] In one embodiment, the duration of each time period may be the same or different; the light-emitting units operating within each time period operate at the same brightness level.

[0064] The duration of the time period can be achieved by dividing the single photosensitive process of the photosensitive point into multiple independent time units. For example, it can be achieved by using a timer module preset inside the driver chip, and the duration of each time unit can be changed by adjusting the counting period or the frequency division coefficient of the timer.

[0065] The same brightness level allows all light-emitting units in operation to use the same current or voltage driving parameters within the same time period. Specifically, this can be achieved by fixing the amplitude or duty cycle of the electrical signal output by the segment driver, ensuring that the light output intensity of each light-emitting unit remains consistent within the same time period.

[0066] Specifically, during a single photosensing process, the driver chip divides the photosensing time into multiple independent time periods, each of which can be set to the same or different durations. For example, in scenarios requiring enhanced exposure in a specific area, the corresponding time period can be set to a longer duration; in scenarios requiring fine-tuning of grayscale, multiple time periods can be set to the same duration to achieve uniformly distributed light intensity superposition. Within each time period, the light-emitting unit operates at only a single brightness level. For instance, in the first time period, all light-emitting units emit light at the highest brightness level, and in subsequent time periods, the brightness level decreases sequentially. By combining different durations and brightness levels, the total light intensity ultimately received by the photosensitive point can be precisely controlled, thereby achieving multi-grayscale output.

[0067] As an example, the duration of each time segment is the same. At any given time point, all LEDs operate at the same brightness: at time t1, they are lit at L4 brightness; at time t2, at L3 brightness; at time t3, at L2 brightness; and at time t4, at L1 brightness. The order of these time segments can be interchanged. For example, higher brightness LEDs can operate first, followed by lower brightness LEDs. After four exposures, the photosensitive drum can obtain 16 different charge levels, thus representing 16 different grayscale levels. This content can be combined with... Figure 5 and Figure 6 To understand, Figure 6 This is a schematic diagram showing the illumination at different brightness levels during different time periods, as provided in this application.

[0068] This application overcomes the limitations of traditional pulse width modulation by flexibly setting combinations of time period duration and brightness levels, while maintaining the stable position of the light-emitting unit. It utilizes time segmentation and brightness level superposition to allow the same photosensitive point to receive exposures at different light intensities, ultimately achieving precise control of multiple grayscale levels. Thus, this application solves the technical problem of existing LED printheads being unable to achieve multiple grayscale levels due to positional displacement caused by the rotation of the photosensitive drum. By dividing time periods and independently controlling the light emission brightness within each time period, multi-level grayscale output is achieved while avoiding positional errors, significantly improving the resolution and color gradation of the printed image.

[0069] In one embodiment, the photosensitivity time is determined based on the pulse width modulation (PWM) time of a pulse width modulation signal used to control the rotational speed of the photosensitive drum of the printer, the pulse width modulation time corresponding to the plurality of time periods.

[0070] The pulse width modulation (PWM) signal can be an electrical signal that controls the motor speed by adjusting the pulse width. For example, it can be implemented by using a microcontroller to generate square wave signals with different duty cycles. This signal changes the rotation speed of the photosensitive drum by adjusting the duty cycle. The pulse width modulation time can be the duration of the high level within one pulse cycle. Specifically, the effective working time can be changed by adjusting the duty cycle. During the printing process, this time parameter is synchronously transmitted to the driver chip as a time reference.

[0071] Specifically, during the printing process, the rotation speed of the photosensitive drum is dynamically controlled by a pulse width modulation (PWM) signal. The driver chip analyzes the pulse width parameter of this signal and divides the photosensitive time into multiple time segments synchronized with the PWM time. Each time segment corresponds to a specific position interval during the rotation of the photosensitive drum, and the light-emitting unit operates at a preset brightness level within the corresponding time segment. For example, when the duty cycle of the PWM signal is 50%, the driver chip can divide the total photosensitive time into four equal-length time segments, each corresponding to a quarter-circle area of ​​the photosensitive drum's rotation angle, thereby ensuring that the exposure position of each photosensitive point is precisely matched with the mechanical movement.

[0072] As an example, Figure 7 This is a schematic diagram illustrating another application scenario of the printhead provided in this application. For example... Figure 7 As shown, the printhead operates by first setting a fixed PWM time width, which matches the printer's photosensitive drum speed. After the LEDData is input, the LEDs are lit sequentially from the most significant bit to the least significant bit. While the LEDs are lit, the drive current of the LEDs can be controlled at different time periods (e.g., the drive current corresponding to the four brightness levels L1-L4), thus controlling the LED brightness level. The PWM time width includes the time for adjusting brightness and the time corresponding to each different time period; in practical applications, the brightness adjustment time is generally small and can be ignored.

[0073] This application establishes a dynamic correspondence between the emission control timing and mechanical movement by directly linking the time parameters of the pulse width modulation signal. This eliminates exposure position deviations caused by rotation speed variations while retaining the precise control advantages of pulse width modulation over mechanical components. Thus, this application achieves precise synchronization between the emission control timing and the mechanical movement of the photosensitive drum, ensuring that the illumination position accurately covers the predetermined area for each time period and avoiding image misalignment caused by rotation speed fluctuations. This solution effectively improves grayscale accuracy through a time-base synchronization mechanism while maintaining the existing pulse width modulation control architecture, without requiring additional position sensors or motion compensation devices.

[0074] In one embodiment, the number of multiple brightness levels is less than or equal to eight; the driver chip 102 is also used to control the brightness level of the light-emitting unit, which decreases or increases sequentially over multiple time periods.

[0075] The multiple brightness levels can be defined as different luminous intensity levels divided by the light-emitting unit during a single photosensitive process at the photosensitive point. This can be achieved by adjusting the driving current or voltage, for example, by using time-division current control technology, with each time period corresponding to a preset current value. This feature achieves multi-level grayscale output with limited control complexity through discrete brightness level division.

[0076] The driver chip 102 controls the brightness levels to decrease or increase sequentially, which can be achieved by gradually changing the luminous intensity according to time sequence. For example, a timing control circuit can be used in conjunction with a preset brightness sequence in the storage unit. This feature, through an ordered sequence of brightness changes, allows the light intensity received by the photosensitive point at different time periods to be superimposed to form a continuous gradient effect, thereby improving grayscale performance.

[0077] Specifically, within one photosensitive cycle of the photosensitive point, the driver chip divides the total photosensitive time into several sub-time periods, each corresponding to a brightness level. For example, when the brightness levels are set to four, the driver chip can output brightness in the following order: 100%, 75%, 50%, 25%, or increasing in the order of 25%, 50%, 75%, 100%. Within each sub-time period, the light-emitting unit maintains a fixed brightness. Through the accumulation of light intensity at different positions during the rotation of the photosensitive drum, the total exposure corresponding to the target grayscale is ultimately formed at the photosensitive point.

[0078] As an example, the brightness levels of the light-emitting units can be sequentially increased over multiple time periods, which can be combined with... Figure 5 This can be understood as follows. For example, depending on the requirements, 4 to 256 gray levels can be selected. 4 gray levels use L1 and L2 brightness levels, while 256 gray levels use 8 brightness levels, which can be L1-L8. This application divides a single photosensitive point's photosensitive time into multiple segments, with the LED having only one brightness level within each segment. Different LED brightness levels can be set for different times. By superimposing these time segments, more gray levels are generated, allowing the print head to support higher grayscale resolutions and improving print quality.

[0079] This application avoids exposure position deviations caused by the rotation of the photosensitive drum through multi-level brightness time-division control under a fixed pulse width. Simultaneously, by utilizing the ordered superposition of discrete brightness levels, multi-level grayscale output is achieved while maintaining a simple driving structure. Thus, this application solves the technical deficiency of existing LED printheads in achieving multi-grayscale output. Employing a time-division control method with no more than eight brightness levels, it significantly improves the resolution and tonal representation of the printed image while ensuring photosensitive position accuracy. This solution, through optimized hardware control logic, achieves grayscale expansion without adding complex circuitry, reducing system cost and power consumption.

[0080] To better illustrate the above-described printhead, this application also provides a printer, including the aforementioned printhead and a photosensitive drum, the photosensitive drum including a plurality of photosensitive dots, each photosensitive dot corresponding to one or more light-emitting units of the printhead.

[0081] The printhead can be a component containing a light-emitting array and a driving chip. For example, it can be implemented using an LED array and integrated circuits to emit controllable light signals to trigger the exposure process of the photosensitive drum.

[0082] The photosensitive drum can be a rotating component with photosensitive dots distributed on its surface. For example, it can be made using a photosensitive material coating. By rotating, different areas receive light in sequence and form a latent image.

[0083] The correspondence between light-emitting units and photosensitive points can be achieved by ensuring that the light projection path of each light-emitting unit uniquely points to one photosensitive point. This can be accomplished through optical lenses or position calibration, ensuring that the light accurately covers the target area and avoiding interference between adjacent photosensitive points. The correspondence between each photosensitive point and multiple light-emitting units in the print head can be understood as a scenario where multiple light-emitting units drive one photosensitive point, such as an RGB three-color light-emitting unit.

[0084] Specifically, the driver chip divides the single exposure time of the photosensitive point into multiple time segments, and controls the corresponding light-emitting unit to emit light at different brightness levels within each time segment. As the photosensitive drum rotates, each photosensitive point sequentially passes through the exposure area corresponding to different time segments, receiving light intensity superimposed from different brightness levels, ultimately accumulating to reach the target brightness. By adjusting the number of time segments and the distribution of brightness levels, such as using a decreasing or increasing brightness sequence, multi-grayscale control can be achieved without changing the emission time. The rotation speed of the photosensitive drum is synchronized with the time segment division, for example, by controlling the rotation speed through a PWM signal, ensuring that each photosensitive point is in a predetermined position within each time segment, thereby avoiding exposure errors caused by positional shifts.

[0085] This application avoids positional offset issues and achieves multi-grayscale control through time-division exposure by superimposing multi-level brightness within a fixed time window, while eliminating the need for complex optical positioning compensation structures. Thus, this application solves the technical problem of existing LED printers' inability to achieve multi-grayscale output. Through the synergistic effect of time-division multi-level brightness control and photosensitive drum rotation, it expands the grayscale range while ensuring exposure position accuracy, thereby improving print quality. Furthermore, this solution simplifies the driver circuit design, reduces hardware costs, and is suitable for high-speed, high-resolution printing scenarios.

[0086] For details regarding the printer, please refer to the detailed description of the foregoing embodiments, which will not be repeated here.

[0087] The printhead and printer provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A printhead, characterized in that, include: A light-emitting array, the light-emitting array comprising a plurality of light-emitting units, each light-emitting unit corresponding to a photosensitive point on a printer; The driving chip is used to divide the photosensitive time of the photosensitive point into multiple time periods, and control the light-emitting unit to emit light according to the brightness level corresponding to each time period, so that the photosensitive point is photosensitive in each time period; wherein the brightness level corresponding to different time periods is different.

2. The printhead according to claim 1, characterized in that, The driving chip is further configured to send a first signal to the light-emitting units in each row of the light-emitting array and a second signal to the light-emitting units in each column; the first signal is used to control the conduction state of the light-emitting units in each row; and the second signal is used to control the brightness level of the light-emitting units in each column.

3. The printhead according to claim 2, characterized in that, The driver chip includes a row driver and a segment driver; the first signal includes a high-level signal and a low-level signal; the second signal includes an electrical signal. The row driver is configured to respond to control commands by providing the high-level signal to the light-emitting units of the selected row and the low-level signal to the light-emitting units of the unselected row. The segment driver is used to control the light-emitting unit of the high-level signal to output the electrical signal within the selected time period based on preset grayscale data.

4. The printhead according to claim 3, characterized in that, The printhead also includes: Multiple power lines, one end of each power line is connected to the anode of a row of light-emitting units, and the other end is connected to the row driver; Multiple control lines, one end of each control line is connected to the cathode of a row of light-emitting units, and the other end is connected to the segment driver.

5. The printhead according to claim 4, characterized in that, The plurality of power lines include a first power line connected to the light-emitting units in odd-numbered rows and a second power line connected to the light-emitting units in even-numbered rows; one of the first power line and the second power line is used to provide the high-level signal, and the other is used to provide the low-level signal.

6. The printhead according to claim 1, characterized in that, The multiple brightness levels are determined based on the target brightness; the two brightness levels corresponding to two adjacent time periods are in a multiple relationship; the light intensity received by the photosensitive point in the multiple time periods is greater than or equal to the light intensity corresponding to the target brightness.

7. The printhead according to claim 1, characterized in that, The duration of each time period may be the same or different; the light-emitting units operating within each time period operate at the same brightness level.

8. The printhead according to claim 1, characterized in that, The photosensitivity time is determined based on the pulse width modulation time of the pulse width modulation signal used to control the rotation speed of the printer's photosensitive drum, and the pulse width modulation time corresponds to the plurality of time periods.

9. The printhead according to any one of claims 1-8, characterized in that, The number of the plurality of brightness levels is less than or equal to eight; The driving chip is also used to control the brightness level of the light-emitting unit, which decreases or increases sequentially over multiple time periods.

10. A printer, characterized in that, The invention comprises a printhead as described in any one of claims 1 to 9 and a photosensitive drum, wherein the photosensitive drum includes a plurality of photosensitive dots, each photosensitive dot being disposed corresponding to one or more light-emitting units of the printhead.

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