JP7707628B2 - Image forming apparatus and current control method - Google Patents

Description

The present invention relates to an image forming apparatus and a current control method.

Image forming devices are known that are equipped with a light source that shines light onto a photosensitive drum to form a latent image on the photosensitive drum.

The image forming device then detects the boundary area between normal pixels and strong exposure pixels. Next, the image forming device converts the pixels in the boundary area into unlit pixels where the light source is unlit. In this way, the image forming device converts some of the normal pixels in the boundary area into strong exposure pixels and converts the remaining pixels into unlit pixels during image formation. In other words, the image forming device sets unlit pixels between normal exposure and strong exposure. This provides a known technology that can accurately correct overshoot and undershoot currents (see, for example, Patent Document 1).

The technology disclosed in Patent Document 1 may not be able to correct the density at the edge to prevent edge effects, etc. Therefore, the conventional technology has the problem of poor image quality at the edge, etc.

The purpose of the present invention is to improve image quality in image formation.

In order to solve the above problems, an image forming apparatus according to one aspect of the present invention comprises:
An input unit for inputting input image data;
a detection unit that detects pixels that become edges among pixels that configure the input image data;
a conversion unit that converts the density of the edge to generate a converted pixel;
an image forming unit that forms an image using a light source that emits light based on the converted pixels;
an adjustment unit that adjusts a current flowing through the light source to adjust the amount of light of the light;
The adjustment unit is
determining an overshoot current or an undershoot current based on an operating mode;
The different operation modes have different edge correction processes.
It is characterized by:

The present invention can improve image quality during image formation.

FIG. 1 illustrates an example of an image forming apparatus 10. FIG. 1 is a diagram showing a processing example (part 1). FIG. 2 is a diagram showing a processing example (part 2). FIG. 3 is a diagram showing a processing example (part 3). FIG. 2 is a diagram illustrating an example of a circuit configuration. FIG. 11 is a diagram illustrating an example of light amount adjustment. FIG. 13 is a diagram illustrating an example of a circuit configuration in a first modified example. 13A and 13B are diagrams illustrating an example of light amount adjustment in a first modified example. FIG. 13 is a diagram illustrating an example of a circuit configuration in a second modified example. 13A and 13B are diagrams illustrating an example of light amount adjustment in a second modified example. FIG. 2 is a diagram illustrating an example of a functional configuration. FIG. 13 is a diagram illustrating an example of an edge effect.

Specific examples are described below with reference to the attached drawings. Note that the embodiment is not limited to the specific examples described below.

[Example of image forming device]
1 is a diagram showing an example of an image forming apparatus 10. For example, the image forming apparatus 10 includes a photoconductor 11, a lens 12, a polygon mirror 13, a polygon control device 14, and a laser diode 15 (sometimes referred to as an "LD"). The image forming apparatus 10 also includes a detection device 16, a light source driving device 17, a data generation device 18, and an image processing device 19. In the following, the image forming apparatus 10 is taken as an example having two of each hardware resource as shown in the figure.

The photoconductor 11 forms a latent image. Specifically, when the photoconductor 11 is irradiated with light emitted by the laser diode 15, a latent image is formed in the area irradiated with the light. Toner is then transferred to the area of the latent image. In other words, a latent image that represents the image to be formed on the recording medium is formed on the photoconductor 11.

The lens 12 and the polygon mirror 13 are examples of optical components. However, other optical components may be used. The lens 12 is, for example, an Fθ lens. When light that has passed through the lens 12 strikes the photoconductor 11, a latent image is formed on the photoconductor 11.

The polygon mirror 13 reflects the light emitted by the laser diode 15. When the polygon mirror 13 rotates, the light scans in one direction (the left-right direction in the figure; hereafter referred to as the "main scanning direction").

The polygon control device 14 is a device that controls the actuators that rotate the polygon mirror 13.

The laser diode 15 is an example of a light source device that emits light. For example, the laser diode 15 is a semiconductor LD, etc.

The detection device 16 is installed on an extension of the photoconductor 11 in the main scanning direction. When the detection device 16 receives light, it outputs a detection signal. The detection signal output in this way indicates the reference timing. For example, the detection signal is used to align the writing start position of image data.

The light source driving device 17 controls the laser diode 15 to turn on or off based on data (hereinafter referred to as "lighting data") generated by the data generating device 18.

The data generating device 18 generates lighting data based on the input image data 20, etc.

The image processing device 19 inputs input image data 20 and the like from an external device such as a personal computer (PC) or a scanner. The image processing device 19 may also perform image processing and data conversion on the input image data 20.

Note that the image forming device 10 is not limited to the hardware configuration described above. Therefore, the image forming device 10 may be equipped with internal or external hardware resources other than those described above.

[Processing example]
For simplicity, the following description will focus on edge detection and correction processing, but the image forming apparatus 10 may also perform processing other than that described below.

Figure 2 shows a processing example (part 1). The following explanation uses the input image data 20 shown in Figure 2 (A) as an example.

Figure 2(A) shows pixels that form images in black. On the other hand, Figure 2(A) shows pixels that do not form images in white (i.e., pixels that remain the color of the recording medium).

For example, the image forming device 10 generates the image data shown in FIG. 2(B) (hereinafter referred to as "first image data 21") and the image data shown in FIG. 2(C) (hereinafter referred to as "second image data 22") based on the input image data 20. Note that the processing is mainly performed by the image processing device 19.

The first image data 21 is the same data as the input image data 20.

The second image data 22 is data that indicates the result of detecting the edge 30.

Edge 30 is detected, for example, by comparing the density of the pixel of interest and the surrounding pixels. Specifically, image forming device 10 sets a threshold value in advance. Next, image forming device 10 judges whether the density of the pixel of interest and the surrounding pixels changes by more than the threshold value, i.e., whether it is a point where the density changes suddenly. Then, if image forming device 10 judges that the pixel of interest is a pixel where the density changes suddenly, it judges it to be edge 30.

In the example shown in FIG. 2(A), an edge 30 is detected when white and black pixels are adjacent in the vertical or horizontal direction. Note that edges 30 are not limited to being detected in the vertical and horizontal directions, and may also be detected in diagonal directions, etc.

The edge 30 may be detected by a process other than the above. For example, the edge 30 may be detected by a filter process or the like. The edge 30 may be detected by taking into consideration not only the adjacent pixels but also the pixels present around the pixel of interest.

As described above, the image forming device 10 performs processing to detect edges 30 on the input image data 20, and generates second image data 22. Next, the image forming device 10 converts the density of the edges 30 based on the second image data 22, etc., as follows:

Figure 3 is a diagram (part 2) showing a processing example. The diagram shows an example of data (hereinafter referred to as "third image data 23") showing the density of the edge 30 after conversion based on the first image data 21 and the second image data 22.

The third image data 23 differs from the first image data 21 in the density of the edge 30. Specifically, the third image data 23 is generated by converting the density of pixels detected as the edge 30 among the pixels forming the image indicated by the first image data 21 (i.e., black pixels in the first image data 21).

The edge 30, i.e., the pixel to be converted, is the pixel indicated by the second image data 22. Hereinafter, the pixel of the edge 30, i.e., the pixel to be converted, is referred to as the "conversion pixel 31". On the other hand, the image forming device 10 maintains the density, etc. of the pixels other than the conversion pixel 31 from the first image data 21.

In the illustrated example, the image forming device 10 converts the density of the edge 30 to a lower value. For example, the density is converted to a value that is set in advance. In this way, the density to which the density of the edge 30 is converted is set in advance.

As described above, when the third image data 23 is generated, the image forming device 10 performs Pulse Width Modulation (PWM) conversion and the like based on the third image data 23. For example, the PWM conversion is mainly performed by the data generating device 18. Specifically, the third image data 23 shown in FIG. 3 is converted as follows.

Figure 4 shows a processing example (part 3). Below, we will explain an example that targets the first line 41, the second line 42, and the third line 43 among the lines that make up the third image data 23.

Figure 4 (B) shows an example of the PWM conversion result. Specifically, the eleventh signal SIG11 is an example of a signal generated by PWM converting the first line 41. Similarly, the twelfth signal SIG12 is an example of a signal generated by PWM converting the second line 42. Furthermore, the thirteenth signal SIG13 is an example of a signal generated by PWM converting the third line 43.

The eleventh signal SIG11, the twelfth signal SIG12, and the thirteenth signal SIG13 represent the density as the time that the light source is turned on. That is, pixels with a high density have a wide width at the High level. On the other hand, pixels with a low density have a narrow width at the High level. In this way, a signal that represents the density as the width of the time that the light source is turned on is generated by PWM conversion. Next, the signal shown in FIG. 4(B) is converted by phase control, for example, as shown in FIG. 4(C).

Figure 4 (C) shows an example of the phase control result. For example, when there are large dots before and after, phase control shifts the phase toward the large dot.

Of the 21st signal SIG21, the 22nd signal SIG22, and the 23rd signal SIG23, the 21st signal SIG21 and the 23rd signal SIG23 are the same before and after phase control.

On the other hand, the 22nd signal SIG22 is different in that it has been converted to shift the phase. In this way, phase control is a process that combines small dots and large dots into one dot. When an image is formed using a signal that has been phase-controlled in this way, a stable image is obtained.

In contrast, when the densities of the surrounding pixels are roughly the same, phase control does not perform any phase shifting processing.

By the above-mentioned process, the image forming device 10 generates, for example, lighting data as shown in FIG. 4(C). The light source is controlled based on the lighting data generated in this way.

Figure 5 shows an example of the circuit configuration.

The light source driving device 17 includes a driving signal generating circuit 171, a switch 172, a D/A converter (hereinafter referred to as "DAC 173"), and a current source 174.

The drive signal generation circuit 171 inputs the lighting data 51. Then, based on the lighting data 51, the drive signal generation circuit 171 generates drive signals such as the bias signal SIG31, the overshoot signal SIG32, and the lighting signal SIG33.

Lighting signal SIG33 is a signal indicated by lighting data 51.

The switch 172 switches the current supplied from the power supply ON/OFF based on the bias signal SIG31, the overshoot signal SIG32, and the lighting signal SIG33, etc.

DAC 173 converts current data 53 into an analog amount. Then, DAC 173 inputs the analog amount to current source 174.

When switch 172 is ON, current source 174 passes a current indicated by the analog quantity through laser diode 15.

Hereinafter, the current that the current source 174 flows based on the lighting signal SIG33 is referred to as the "switching current Isw." The current that the current source 174 flows based on the overshoot signal SIG32 is referred to as the "overshoot current Iov." The current that the current source 174 flows based on the bias signal SIG31 is referred to as the "bias current Ib."

The current flowing through the laser diode 15 is called the "total current It." The total current It is sometimes called the drive current, etc.

Current data 53, i.e., the current supplied by current source 174, is set, for example, by setting data 52. Note that setting data 52 may be determined, for example, by an operating mode, etc.

[Example of light intensity adjustment]
6A and 6B are diagrams showing examples of light amount adjustment. For example, the image forming apparatus 10 adjusts the amount of light emitted by the laser diode 15 based on a signal shown in Fig. 6A. The adjustment is mainly performed by the light source driving device 17.

The delay signal SIG41 is a signal that is a delayed version of the lighting signal SIG33. For example, the delay signal SIG41 is generated by inputting the lighting signal SIG33 to a delay element.

Bias signal SIG31 is a signal that causes bias current Ib to flow when it goes to high level. Hereinafter, each signal is considered to be a HighActive signal, with a high level being "ON" and a low level being "OFF."

The bias current Ib is a current that is passed so that the laser diode 15 smoothly starts emitting light. Therefore, the bias current Ib is a current at which the laser diode 15 does not emit light. For example, the bias current Ib is set to ON (high level in the figure) while the image forming device 10 is operating. The bias current Ib is also set in advance according to the characteristics of the laser diode 15, etc.

The overshoot signal SIG32 is a signal that detects the rising edge of the lighting signal SIG33, i.e., an overshoot. For example, when the lighting signal SIG33 is at a high level and the delay signal SIG41 is at a low level, the overshoot signal SIG32 detects the rising edge and turns ON. In this way, the rising edge of the signal can be detected by using the lighting signal SIG33 and the delay signal SIG41.

When detecting the falling edge, the image forming device 10 detects the timing when the lighting signal SIG33 is at a low level and the delay signal SIG41 is at a high level. In this way, the falling edge of the signal can be detected by using the lighting signal SIG33 and the delay signal SIG41.

The total current It is adjusted as shown in FIG. 6(B). In this way, it is desirable to adjust the light intensity by adjusting the current. Specifically, as a result of the adjustment in FIG. 6(B), the light intensity becomes as shown in FIG. 6(C).

As shown in FIG. 6(B), when the bias signal SIG31 is turned ON, the bias current Ib flows as the total current It. Furthermore, when the lighting signal SIG33 is turned ON, the switching current Isw is added to the total current It. Similarly, when the overshoot signal SIG32 is turned ON, the overshoot current Iov flows as the total current It. The relationship between the total current It determined in this way and the light amount is as shown in FIG. 6(C).

At the first timing T1, the lighting signal SIG33 rises, and the overshoot signal SIG32 turns ON. Therefore, from the first timing T1, while the overshoot signal SIG32 is ON, the total current It becomes the current shown in the following formula (1).

It = Ib + Isw + Iov (1)

As shown in the above formula (1), the total current It is adjusted so that the overshoot current Iov flows at the first timing T1. In this way, the overshoot current Iov is a current that flows in addition to the bias current Ib and the switching current Isw. Hereinafter, the light amount after adjustment by the overshoot current Iov etc. is referred to as the "adjusted light amount La." In the figure, the adjusted light amount La is shown by a solid line.

If the overshoot current Iov is not applied, the light intensity tends to become the pre-adjustment light intensity Lb (indicated by the dotted line in the figure). A phenomenon such as the pre-adjustment light intensity Lb is caused by parasitic capacitance present in the light source and the board on which the light source is mounted.

Parasitic capacitance is also called floating capacitance or stray capacitance. Parasitic capacitance is, for example, the electrostatic capacitance of electronic components.

When starting up, current flows through the parasitic capacitance until it is charged. As a result, the current flowing through the light source decreases by the amount flowing through the parasitic capacitance, and the light intensity tends to become dull, like the pre-adjustment light intensity Lb. Therefore, assuming that current flows through the parasitic capacitance, an overshoot current Iov is added to the total current It.

By adjusting the current to flow an overshoot current Iov, the current flowing through the parasitic capacitance is compensated for, and at the first timing T1, the light intensity can be increased sharply to the adjusted light intensity La.

Increasing the amount of light increases the amount of toner that adheres to the latent image. Therefore, in order to reduce the edge effect on the edges 30 and the like, the image forming device 10 converts the edge 30 to lower its density. However, converting to lower the density can easily make the edge 30 thinner. Therefore, by making adjustments such as passing an overshoot current Iov, the image forming device 10 adjusts the amount of light so that the edge effect is less likely to occur and the amount of toner is optimized. In this way, the density and amount of toner are optimized. And by optimizing the amount of toner, the image forming device 10 can improve image quality.

The time to form one dot may differ depending on the speed at which the image is formed (this may be the "printing speed" or "linear speed", etc.). In such cases, the proportion of the overshoot current Iov in the formation of one dot also differs. Therefore, it is desirable to determine the overshoot current Iov according to the speed at which the image is formed, etc. In this way, the image forming device 10 determines the overshoot current Iov according to the speed at which the image is formed, and thereby enables image processing and current control suitable for the speed at which the image is formed.

[First Modification]
The image forming apparatus 10 may have the following configuration.

Figure 7 is a diagram showing an example of a circuit configuration in the first modified example. Compared to Figure 5, the circuit configuration shown in Figure 7 differs in that there are two current sources 174 for overshooting. Below, the differences will be mainly described, and duplicated explanations will be omitted.

Hereinafter, the current that the current source 174 flows based on the first overshoot signal SIG321 is referred to as the "first overshoot current Iov1." The current that the current source 174 flows based on the second overshoot signal SIG322 is referred to as the "second overshoot current Iov2."

In addition, in the first variant, the switching current Isw flows when the delay signal SIG41 is turned ON.

Figure 8 is a diagram showing an example of light intensity adjustment in the first modified example. Compared to Figure 6, it differs in that a second delay signal SIG42 is added. Also, it differs in that the overshoot signal SIG32 becomes a first overshoot signal SIG321 and a second overshoot signal SIG322. Hereinafter, similar signals are given the same reference numerals and descriptions are omitted.

The first overshoot signal SIG321 is a signal similar to the overshoot signal SIG32 in FIG. 6. In other words, the first overshoot signal SIG321 is a signal that indicates the rising edge of the delay signal SIG41.

For example, the first overshoot signal SIG321 is a signal that is ON when the delay signal SIG41 is at a high level and the second delay signal SIG42 is at a low level. In this way, the rising edge can be detected by using the delay signal SIG41 and the second delay signal SIG42.

The first overshoot signal SIG321 controls the first overshoot current Iov1 to flow at the first timing T1, similar to FIG. 6.

The second delayed signal SIG42 is a signal in which the lighting signal SIG33 is further delayed than the delayed signal SIG41 by a delay element or the like.

The second overshoot signal SIG322 is a signal that indicates the falling edge of the delayed signal SIG41.

For example, the second overshoot signal SIG322 is a signal that is ON when the lighting signal SIG33 is at a low level and the delay signal SIG41 is at a high level. In this way, the falling edge can be detected by using the lighting signal SIG33 and the delay signal SIG41.

At the second timing T2 when the second overshoot signal SIG322 turns ON, the second overshoot current Iov2 flows.

Therefore, in the first modified example, at the first timing T1, the total current It is as shown in the following formula (2).

It = Ib + Isw + Iov1 (2)

Furthermore, at the second timing T2, the total current It is as shown in the following formula (3).

It = Ib + Isw + Iov2 (3)

As described above, the image forming device 10 adjusts the rise of the current with the first overshoot current Iov1, and also adjusts the current immediately before the light source is turned off with the second overshoot current Iov2. By adjusting in this way, the image forming device 10 can adjust the light amount to increase both the rise and fall of the current, as shown by the adjusted light amount La.

For example, in the case of the edge 30 shown in FIG. 2, the image forming device 10 can optimize the amount of toner for both the edge 30 located at the left end and the edge 30 located at the right end.

[Second Modification]
9 is a diagram showing an example of a circuit configuration in the second modified example. Compared to the first modified example, the second modified example differs in that a current source 174 for undershoot is added. The following mainly describes the differences from the first modified example.

Hereinafter, the current that the current source 174 flows based on the undershoot signal SIG5 is referred to as the "undershoot current Iud." In other words, when the undershoot signal SIG5 is turned ON, the undershoot current Iud flows.

The undershoot current Iud is a current that flows in the opposite direction to the current that causes the light source to emit light, such as the first overshoot current Iov1.

Figure 10 shows an example of adjusting the light intensity in the second modified example.

The undershoot signal SIG5 is a signal that indicates the falling edge of the delayed signal SIG41.

For example, the undershoot signal SIG5 is a signal that is ON when the delay signal SIG41 is at a low level and the second delay signal SIG42 is at a high level. In this way, the falling edge can be detected by using the delay signal SIG41 and the second delay signal SIG42.

Without the undershoot current Iud, the charges held in the parasitic capacitance would flow to the light source, and the light intensity would tend to become dull, like the pre-adjustment light intensity Lb.

On the other hand, if adjustment is made to flow an undershoot current Iud, the light intensity can be reduced sharply to the adjusted light intensity La.

As described above, the image forming device 10 adjusts the rise of the current with the first overshoot current Iov1, and also adjusts it with the second overshoot current Iov2 just before the light source is turned off.

If the light source is turned off slowly, as with the pre-adjustment light amount Lb, unnecessary dots may be formed at the boundary between positions where image formation is performed and positions where image formation is not performed.

Therefore, the image forming device 10 adjusts the current so that it drops sharply at the boundary, as in the adjusted light amount La. In this way, it is possible to prevent unnecessary toner from adhering and improve image quality. It is also possible to prevent unnecessary toner from adhering and optimize the amount of toner.

[Example of processing based on operation mode, etc.]
It is desirable for the image forming apparatus 10 to perform processing taking into consideration the operation mode, for example, as follows.

The operation mode is information that indicates the purpose of image formation performed by the image forming device 10, such as copying or a printer. For example, the operation mode is set by a user operation.

Different operating modes often require different image quality. For this reason, the image forming device 10 performs different image processing depending on the operating mode. For example, different operating modes result in different correction processes for the edge 30.

Therefore, by adjusting the current based on the operating mode, the image forming device 10 can perform more optimal image processing and current control.

As with the operating mode, the required image quality may differ depending on the conditions of the image formation, such as the speed, image quality, or type of recording medium. Therefore, when the image forming device 10 adjusts the current based on the conditions of the image formation, such as the speed, image quality, or type of recording medium, the image forming device 10 can perform more optimal image processing and current control.

[Functional configuration example]
11 is a diagram showing an example of a functional configuration. For example, the image forming device 10 includes an input unit 10F1, a detection unit 10F2, a conversion unit 10F3, an image forming unit 10F4, an adjustment unit 10F5, and an image creating unit 10F7. It is preferable that the image forming device 10 further includes an operation mode setting unit 10F6 as shown in the figure. The following describes the functional configuration shown in the figure as an example.

The input unit 10F1 performs an input procedure for inputting the input image data 20. For example, the input unit 10F1 is realized by an input device or the like included in the image processing device 19.

The detection unit 10F2 performs a detection procedure to detect pixels that are edges among the pixels that make up the input image data 20. For example, the input unit 10F1 is realized by a calculation device or the like included in the image processing device 19.

The conversion unit 10F3 performs a conversion procedure that converts the density of the edge to generate a converted pixel. For example, the conversion unit 10F3 is realized by a calculation device or the like included in the image processing device 19.

The image forming unit 10F4 performs an image formation procedure to form an image using a light source that emits light based on the converted pixels. For example, the image forming unit 10F4 is realized by a light source driving device 17, etc.

The adjustment unit 10F5 performs an adjustment procedure to adjust the amount of light by adjusting the current flowing through the light source. For example, the adjustment unit 10F5 is realized by the light source driving device 17, etc.

The operation mode setting unit 10F6 performs an operation mode setting procedure to set an operation mode. For example, the operation mode setting unit 10F6 is realized by an input device or the like included in the image processing device 19. The input device accepts the operation mode or the like through user operation or the like.

The imaging unit 10F7 includes, for example, a laser diode 15 and a photoconductor 11.

The image forming device 10 forms an image on a recording medium and outputs a printed matter, etc.

With the above configuration, the image forming device 10 can convert the density of the edges and perform correction to reduce the density to a level that prevents edge effects, etc. In other words, with conventional technology, it may not be possible to reduce the density to a level that prevents edge effects, etc. On the other hand, with the configuration of the present application, the image forming device 10 can perform correction to sufficiently reduce the density to a level that prevents edge effects, etc. Therefore, the image forming device 10 can prevent edge effects, etc. and improve image quality.

Figure 12 is a diagram showing an example of the edge effect. For example, when forming an image as shown in Figure 12 (A) or Figure 12 (B), the image may be formed using signals as shown in Figure 12 (C) and Figure 12 (D).

When such a signal is used, a phenomenon known as the edge effect occurs, in which toner adheres unnecessarily to edge positions. To prevent this edge effect from occurring, the image forming device 10 performs correction to reduce the density of the edges. For example, the image forming device 10 performs processing as shown in FIG. 3. Then, the image forming device 10 forms an image based on the converted pixels.

When forming an image, the image forming device 10 adjusts the current flowing through the light source at the rising and falling edges of the current to adjust the amount of light emitted by the light source. In this way, adjusting the amount of light with the current allows fine adjustments.

In addition, in conventional technology, lowering the density enough to suppress the edge effect can sometimes result in a deterioration in image quality. On the other hand, the image forming device 10 described above adjusts the amount of light by adjusting the current, so that the amount of toner can be optimized and image quality can be improved, even if the density is lowered.

[Other embodiments]
In the current control method described above, for example, some of the processing may be realized by a program such as firmware. That is, the current control method is a method executed by a computer by causing an arithmetic unit, a storage unit, an input unit, an output unit, and a control unit to cooperate with each other and operate based on the program. In addition, the program may be written to a storage unit or a storage medium, etc. and distributed, or distributed through a telecommunication line, etc.

Each of the devices described above does not have to be a single device. In other words, each device may be a system made up of multiple devices.

The image forming device may be, for example, a commercial printing machine (such as a large electrophotographic printer or an inkjet printer).

The recording medium is, for example, paper (also called "plain paper"). However, the recording medium may be coated paper other than paper, label paper, overhead projector sheet, film, or flexible thin plate, etc. The recording medium may also be roll paper, etc.

In other words, the material of the recording medium may be any material to which ink droplets or paint such as toner can adhere, can adhere temporarily, can adhere and stick, or can adhere and penetrate.

Specifically, the recording medium may be a recording medium such as paper, film, or cloth, an electronic circuit board, an electronic component such as a piezoelectric element (also called a "piezoelectric member"), a powder layer (also called a "powder layer"), an organ model, or a test cell, etc.

As such, the material of the recording medium may be any material to which paint can be attached, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, or a combination of these.

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the technical gist of the present invention. All technical matters included in the technical ideas described in the claims are covered by the present invention. The above-described embodiments are preferred examples, but a person skilled in the art can realize various modifications from the disclosed contents. Such modifications are also included in the technical scope described in the claims.

10: Image forming apparatus 10F1: Input section 10F2: Detection section 10F3: Conversion section 10F4: Image forming section 10F5: Adjustment section 10F6: Operation mode setting section 20: Input image data 30: Edge 31: Conversion pixel Ib: Bias current Iov: Overshoot current Iov1: First overshoot current Iov2: Second overshoot current Isw: Switching current It: Total current Iud: Undershoot current La: Adjusted light amount Lb: Pre-adjusted light amount SIG32: Overshoot signal SIG321: First overshoot signal SIG322: Second overshoot signal SIG5: Undershoot signal T1: First timing T2: Second timing

JP 2018-24186 A

Claims (6)

An input unit for inputting input image data;
a detection unit that detects pixels that become edges among pixels that configure the input image data;
a conversion unit that converts the density of the edge to generate a converted pixel;
an image forming unit that forms an image using a light source that emits light based on the converted pixels;
an adjustment unit that adjusts a current flowing through the light source to adjust the amount of light of the light;
The adjustment unit is
determining an overshoot current or an undershoot current based on an operating mode;
The different operation modes have different edge correction processes.
Image forming device. The adjustment unit is
2. The image forming apparatus according to claim 1, wherein the bias current and the overshoot current to be added to the switching current are determined based on the image forming speed, image quality, or type of recording medium. An operation mode setting unit that sets an operation mode,
The adjustment unit is
3. The image forming apparatus according to claim 1, wherein a bias current and an overshoot current to be added to a switching current are determined based on the operation mode. The adjustment unit is
4. The image forming apparatus according to claim 1, wherein the current is adjusted at rising and falling timings of a signal that controls the current. The adjustment unit is
5. The image forming apparatus according to claim 1, wherein adjustment is made so that an undershoot current flows in a direction opposite to a direction in which the light source emits light at a timing of a falling edge of a signal that controls the current. A current control method performed by an image forming apparatus, comprising:
an input step in which the image forming apparatus inputs input image data;
a detection step in which an image forming apparatus detects pixels that become edges among pixels that constitute the input image data;
a conversion step in which the image forming device converts the density of the edge to generate a converted pixel;
an image forming step in which an image forming device forms an image using a light source that emits light based on the converted pixels;
an adjustment step in which the image forming apparatus adjusts a current flowing through the light source to adjust the amount of light of the light;
In the adjustment procedure,
determining an overshoot current or an undershoot current based on an operating mode;
The different operation modes have different edge correction processes.
Current control method.