JP2011180363A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of estimating the amount of attached toner, while suppressing increase in a circuit scale. <P>SOLUTION: The image forming apparatus includes a generating means (a decompressing section 60) for generating for each line after a reference line, line data by applying a difference between the line data of the preceding line and the line data of this line to the line data of the preceding line; a first counting means (dot-counting section 63) for counting the numbers of dots formed on a recording medium, on the basis of line data; a second counting means (dot-counting section 63) for counting pixels that differ in the presence/absence of dots formed between the pixels, at identical position orthogonal to the line of the line data of the preceding line of pixels constituting the line data; an estimating means (CPU) for estimating the amount of toner attached to the recording medium on the basis of the counted dots and the total of the pixels counted for each line. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  Conventionally, an image forming apparatus that calculates a toner consumption amount in a state in which toner dots are two-dimensionally arranged has been disclosed (for example, see Patent Document 1). In this image forming apparatus, line-shaped latent images for a plurality of lines are stored, and based on the line-shaped latent images, toner dots are classified and counted according to the number of adjacent dots present around them. The toner consumption amount is obtained by multiplying each count value by a coefficient corresponding to the classification and adding the result.

JP 2006-098952 A

However, according to the conventional image forming apparatus, in order to determine the two-dimensional arrangement state of the toner dots, the line-shaped latent images for a plurality of lines must be stored, thereby calculating the toner consumption amount. There has been a problem that the circuit scale of the system becomes large.
The present invention has been completed based on the above circumstances, and an object of the present invention is to provide an image forming apparatus capable of estimating the amount of color material attached while suppressing an increase in circuit scale.

  A first aspect of the present invention is an image forming apparatus for forming an image on a recording medium by forming color material dots on the recording medium based on line data representing a dot pattern for one line. Storage means for storing the difference information indicating the difference between the line data of the previous line and the line data of the immediately preceding line for each line after the reference line, and the line data of the immediately preceding line for each line after the reference line Generating means for generating line data of the line by applying the difference of the lines; and first counting means for counting the number of dots formed on the recording medium based on the line data of each line; For each line after the reference line, the line data of the immediately preceding line among the pixels constituting the line data of the line. A second counting unit that counts the number of pixels in which dot formation is different from the pixels at the same position in the orthogonal direction based on the difference information of the line, and the first counting unit. Estimating means for estimating the amount of the color material attached to the recording medium based on the number of dots and the total number of pixels counted for each line by the second counting means; Is provided.

  According to the present invention, the second counting means forms dots between the pixels constituting the line data of the target line (the line) and the pixels at the same position in the line orthogonal direction of the line data of the immediately preceding line. The number of pixels with different presence or absence is counted based on the difference information of the target line. For this reason, the second counting means only needs to store the difference information for one line at a time, and does not need to store the line data for a plurality of lines at the same time for counting. Thereby, the circuit scale of the second counting means can be reduced. Therefore, according to this invention, the adhesion amount of the coloring material can be estimated while suppressing an increase in circuit scale.

A second invention is the image forming apparatus according to the first invention, wherein the estimating means counts the number of dots counted by the first counting means, d, and counts for each line by the second counting means. When the total number of pixels obtained is s, the color material adhesion amount is estimated by Equation (1).
Adhesion amount = d × coefficient A + s × coefficient B Equation 1
According to this invention, it is possible to estimate the adhesion amount of the coloring material while suppressing an increase in circuit scale.

A third invention is the image forming apparatus according to the first invention, wherein the second counting means forms a dot in a pixel at the same position in the line data of the immediately preceding line and does not form a dot in the line. The number of the first pixels and the number of second pixels in which dots are not formed in the pixels at the same position in the line data of the immediately preceding line but dots are formed in the line, respectively, The number of dots counted by the first counting means is d, the total number of the first pixels counted for each line by the second counting means is m, and the number of the second pixels When the total number is n, the color material adhesion amount is estimated by Equation 2.
Adhesion amount = d × coefficient A + m × coefficient C + n × coefficient D Equation 2
According to the present invention, since the coefficients can be made different between the first pixel and the second pixel, it is possible to estimate the adhesion amount of the coloring material more accurately.

The fourth invention is the image forming apparatus according to the third invention, wherein other dots of the line are not formed adjacent to one side in the line direction on the same line based on the line data of each line. Third counting means for counting the number of third pixels representing dots and the number of fourth pixels representing dots on which the other dots of the line are not formed adjacent to each other on the other side in the line direction; The estimating means includes p as the total number of the third pixels counted for each line by the third counting means, and q as the total number of the fourth pixels. The adhesion amount of the coloring material is estimated by Equation 3.
Adhesion amount = d × coefficient A + m × coefficient C + n × coefficient D + p × coefficient E + q × coefficient F
According to the present invention, since the coefficients can be made different between the first to fourth pixels, it is possible to estimate the adhesion amount of the coloring material more accurately. The coefficients C, D, E, and F may be the same value or different values.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesion amount of a coloring material can be estimated, suppressing the enlargement of a circuit scale.

1 is a side sectional view of a main part of a laser printer according to Embodiment 1 of the present invention. The block diagram which shows the structure of the controller of a halftone data and a scanner part. The schematic diagram for demonstrating the front line comparison compression system. The schematic diagram for demonstrating adhesion of the coloring material to a paper. The schematic diagram for demonstrating adhesion of the coloring material to a paper.

<Embodiment 1>
A first embodiment of the present invention will be described with reference to FIGS.
(1) Configuration of Laser Printer FIG. 1 is a side sectional view of an essential part of a laser printer 1 (an example of an image forming apparatus, hereinafter referred to as “printer”) according to Embodiment 1 of the present invention. The printer 1 includes a main body case 10, a control unit 20, a feeder unit 30, an image forming unit 40, and the like.

The control unit 20 (an example of an estimation unit and a storage unit) includes a CPU, a ROM, a RAM 12 (see FIG. 2), and the like, and controls each unit of the printer 1.
The feeder unit 30 includes a paper feed tray 31, a paper pressing plate 32, a paper feed roller 33, a pair of registration rollers 34, and the like. The sheet pressing plate 32 is rotatable around its rear end, and the uppermost sheet 3 (an example of a recording medium) on the sheet pressing plate 32 is pressed toward the sheet feeding roller 33. The paper 3 is fed one by one by the rotation of the paper feed roller 33, registered by the registration roller 34, and then sent to the transfer position X. The transfer position X is a position at which the toner image on the photosensitive drum 49 is transferred to the paper 3 and the photosensitive drum 49 and the transfer roller 43 are in contact with each other.

The image forming unit 40 includes a scanner unit 41, a process cartridge 42, a transfer roller 43, and a fixing unit 44.
The scanner unit 41 includes a laser light emitting unit (not shown), a controller 53 (see FIG. 2) that controls the laser light emitting unit, a polygon mirror 45, a motor 46 that rotationally drives the polygon mirror 45, and the like. The laser light emitted from the laser light emitting unit (the one-dot chain line L in the figure) is deflected by the rotating polygon mirror 45 and irradiated onto the surface of the photosensitive drum 49.

The process cartridge 42 includes a toner storage chamber 46, a supply roller 47, a developing roller 48, a photosensitive drum 49, a charger 50, and a layer thickness regulating blade 51.
The toner storage chamber 46 stores positively charged nonmagnetic polymerized toner (an example of a color material).
The charger 50 is, for example, a scorotron charger, and uniformly charges the surface of the photosensitive drum 49 to a positive polarity. Thereafter, the surface of the photosensitive drum 49 is exposed by laser light from the scanner unit 41 to form an electrostatic latent image.

  The toner stored in the toner storage chamber 46 is supplied to the supply roller 47 and is supplied to the developing roller 48 by the rotation of the supply roller 47. The toner supplied to the developing roller 48 enters between the layer thickness regulating blade 51 and the developing roller 48 as the developing roller 48 rotates, and is carried on the developing roller 48 as a thin layer having a certain thickness. Next, the toner carried on the surface of the developing roller 48 is supplied to the electrostatic latent image on the photosensitive drum 49 by a voltage difference, whereby a toner image is formed on the photosensitive drum 49. The toner image formed on the photosensitive drum 49 is attracted to the transfer roller 43 to which a negative voltage is applied and adheres to the paper 3.

The fixing unit 44 includes a heating roller 51 and a pressing roller 52. The pressing roller 52 presses the sheet 3 against the heated heating roller 51 to thermally fix the toner to the sheet 3.
The printer 1 also includes a communication interface (not shown) for receiving halftone data from an external device such as a personal computer.

(2) Configuration of Halftone Data and Controller of Scanner Unit FIG. 2 is a block diagram showing the halftone data stored in the RAM 12 and the controller 53 of the scanner unit 41.

(2-1) Halftone Data Halftone data is binary data that represents an intermediate color according to dot density, and is generated for each toner color. Since the printer 1 of this embodiment is a monochrome printer, halftone data for one black color is generated.
The halftone data is generated by a printer driver that is executed by an external device that is communicably connected to the printer 1, compressed, and output to the printer 1. In the present embodiment, as a halftone data compression method, a compression method combining a previous line comparison compression method and a run length method will be described as an example.

  FIG. 3 is a schematic diagram for explaining the previous line comparison compression method. FIG. 3 shows the line data of the first line (an example of the reference line) of the halftone data before compression and the line data of the second line. Line data is data representing a dot pattern for one line by a bit (an example of a pixel). The value (bit value) of each bit of the line data indicates the presence / absence of dot formation. For example, if the bit value is 1, it indicates that a dot is formed (with dot formation), and if the bit value is 0, it indicates that no dot is formed (no dot formation). Forming dots means attaching toner to the paper 3 in the form of minute dots, and an image is formed on the paper 3 by a set of toner (dots) adhering to the dots. For example, dots are formed with a size of 600 in one inch.

In the previous line comparison compression method, the CPU of the control unit 20 stores the line data as it is as halftone data in the RAM 12 for the first line, and stores the difference information from the previous line in the RAM 12 for the second and subsequent lines.
The difference information is information indicating, for example, bits in which dot formation is different between bits forming the line data of the second line and bits located at the same position in the line orthogonal direction of the line data of the first line. . The bit at the same position in the line orthogonal direction of the line data of the first line with respect to the bit of the line data of the second line is the same bit number as the bit of the certain bit of the second line Means a bit. The bit number is a number indicating the number of bits from the beginning (or the end) in the bit string constituting the line data.

  For example, there is no dot formation of a bit in the line data of the first line (bit value is 0), and the bit at the same position (hereinafter simply referred to as “the same position”) in the line orthogonal direction of the line data of the second line If there is dot formation (bit value is 1), 1 is set as the difference value (an example of difference) of the bit in the second line. Conversely, if there is dot formation for a bit in the line data of the first line and there is no dot formation for a bit in the same position of the line data for the second line, the difference value of the bit for the second line Is set to 0. The bit for which the difference value is set is stored as difference information in association with the bit number and the difference value.

  On the other hand, when there is no dot formation of a bit in the line data of the first line, and there is no dot formation of the bit at the same position of the line data of the second line, and When dot formation is present and dot formation of the bit at the same position of the line data of the second line is also present, no difference value is set for the bit of the second line. Bit numbers of bits for which no difference value is set are not stored in the difference information.

  When the previous line comparison compression method is used, the data amount of the difference information can be reduced when the number of bits in which dot formation is different between the line data of the target line and the line data of the immediately preceding line is small. For this reason, the previous line comparison compression method is particularly suitable for compression of a page having a small number of bits that are different in dot formation from the previous line, such as a document.

  The run-length method is a method of compressing the data amount by storing a number of consecutive 0s and a number of consecutive 1s, instead of storing a numeric string of 0s and 1s as they are.

(2-2) Configuration of Controller of Scanner Unit Returning to FIG. 2, the controller 53 is configured as an ASIC, and includes a decompression unit 60, SRAM 61, data output unit 62, and dot count unit 63.
The decompression unit 60 (an example of a generation unit) is a circuit that decompresses halftone data stored in the RAM 12 line by line and generates line data. The generation of line data by the decompression unit 60 will be described later.

  The data output unit 62 is a circuit that reads the line data generated by the decompression unit 60 from the SRAM 61 and outputs it as a Video signal to the laser emission unit. The data output unit 62 outputs a Video signal to the laser emitting unit in synchronization with the timing at which the laser beam deflected by the polygon mirror 45 is detected by a light receiving sensor (not shown), and the laser emitting unit is based on the Video signal. Causes a laser diode (not shown) to blink, whereby an electrostatic latent image for one line is formed on the surface of the photosensitive drum 49.

  The dot count unit 63 (an example of the first counting unit and the second counting unit) is configured to create a dot between the number of dots formed on the paper 3 and the bit at the same position of the line data of the immediately preceding line for each line. The number of bits that are formed differently, the number of bits that do not have other dots formed adjacent to one side in the line direction on the same line, and the other dots in the line on the other side in the line direction This circuit counts the number of bits not formed adjacent to each other. The counting by the dot count unit 63 will be described later.

(3) Generation of Line Data Next, generation of line data by the decompression unit 60 will be described. The decompression unit 60 generates line data of the line by applying the difference indicated by the difference information of the line to the line data of the line immediately before the line (immediate line) for each line after the head line. To do.

  For example, as shown in FIG. 3, if the difference information of the first line and the difference value of the second bit are not set in the difference information of the second line, the decompressing unit 60 first extracts line data of the first line. The bit and the bit value of the second bit are left as they are. If the difference value of the third bit in the difference information of the second line is 1, it means that the dot formation of the third bit is present. The bit value of the third bit is changed to 1.

  If a difference value is also set for the fourth bit and the difference value is 0, it means that there is no dot formation for the fourth bit. The bit value of the fourth bit of line data is changed to 0. By repeating the above processing for the fifth and subsequent bits, the line data of the first line is converted into the line data of the second line. That is, line data for the second line is generated. Next, similarly, the decompression unit 60 generates the third line data by applying the third line difference information to the generated second line data. Line data is generated in order in the same manner for the fourth and subsequent lines.

(4) Adhesion of Toner FIGS. 4A and 4B are schematic diagrams for explaining the adhesion of toner to the paper 3. FIG. 4A shows two dots 71A and 71B formed apart from each other in the direction perpendicular to the line, and a graph showing the amount of toner adhering on a straight line 74 virtually extending in the direction perpendicular to the line. Two dots 72A and 72B formed adjacent to each other in the orthogonal direction, and a graph showing the amount of toner adhering to a straight line 75 virtually extending in the line orthogonal direction are shown. A rectangular frame 73 indicated by a broken line in FIGS. 4A and 4B indicates a region for one dot (five rectangular frames 73 are shown in FIGS. 4A and 4B, respectively).

  When a plurality of dots are formed, the amount of toner attached to the paper 3 differs depending on whether the dots are formed apart from each other. The reason for this is that, as shown in FIG. 4A, when two dots 71A and 71B are formed apart from each other, for example, from the rectangular frame 73 on the dot 71A to the other dot 71B side of the toner that forms the dot 71A. This is because the protruding toner 92 adheres to the sheet 3.

  As described above, since the thickness of the toner carried on the developing roller 48 becomes a constant thickness by the layer thickness regulating blade 51, the thickness of the toner adhering to the paper 3 does not exceed that thickness. For this reason, when two dots 72A and 72B are formed adjacent to each other as shown in FIG. 4B, the dot 72A is formed before the dot 72B, but the portion that protrudes from the dot 72A to the other dot 72B side. The toner of the dot 72B does not overlap the toner of the dot 72B, and the thickness of the toner of the dot 72B does not become thicker than the dots 71A and 71B. On the other hand, when two dots 71A and 71B are formed apart from each other as shown in FIG. 4A, the toner protrudes from one dot to the other dot side (the toner 92 and dot 71B of the dot 71A in FIG. 4A). Toner 91) adheres to the paper 3, and therefore, the amount of toner adhering to the paper 3 increases correspondingly as compared with the case shown in FIG. 4B.

  Here, the case where dots are formed spaced apart and adjacent to each other in the direction orthogonal to the line has been described as an example, but the same applies to the line direction, and adjacent to the case where dots are formed spaced apart in the line direction. Even when the toner is formed, the toner adhesion amount is different. In this embodiment, in addition to the difference in the amount of toner adhesion when dots are formed spaced apart and adjacent to each other in the direction perpendicular to the line, the amount of toner adhesion when dots are formed spaced apart and adjacent to each other in the line direction. In consideration of the difference, the toner adhesion amount is estimated.

(5) Estimating the toner adhesion amount The toner adhesion amount is estimated by multiplying the product of the number of dots formed on the paper 3 and the toner amount adhering in the area for 1 dot from the area for 1 dot (immediately before This is done by adding the amount of toner that sticks out to the sheet 3 and protrudes to the lower side (next line side), left side (one side in the line direction), and right side (the other side in the line direction). Hereinafter, the process for estimating the toner adhesion amount will be described with reference to FIG.

First, the decompression unit 60 reads line data of the first line from the RAM 12 and stores it in the decompression unit 60.
Next, the decompressing unit 60 outputs the line data of the first line to both the SRAM 61 and the dot count unit 63 while storing the line data of the first line.
When the line data of the leading line is output, the dot counting unit 63 counts the number of dots formed by the leading line by counting the number of bits having a value of 1 from the line data of the leading line. When the number of dots formed by the head line is counted, the dot count unit 63 outputs the number to the CPU of the control unit 20.

  Next, the dot count unit 63 assumes that the line extends in the left-right direction, and is a bit (third) representing a dot that is a dot on the top line and that is not formed adjacent to the other dots on the left side on the left side. The number of pixels (hereinafter referred to as “third bit”) is counted. For example, in FIG. 3, bit 80 indicates a bit that represents a dot on the left side where other dots on the top line are not formed adjacent to each other. The number of third bits is counted by adding 1 when the bit value of the leftmost bit is 1 to the number of change points where the bit value changes from 0 to 1 in the line data of the first line. be able to. When the dot count unit 63 counts the number of third bits, it outputs the number to the CPU.

  Next, the dot count unit 63 represents a dot (an example of a fourth pixel, hereinafter referred to as a “fourth bit”) that represents a dot that is a dot on the leading line and is not formed adjacent to the other dots on the right side on the right side. ). For example, in FIG. 3, bit 81 indicates a bit representing a dot on the right side where other dots of the leading line are not formed adjacent to each other. The number of the fourth bits is counted by adding 1 when the bit value of the rightmost bit is 1 to the number of change points where the bit value changes from 1 to 0 in the line data of the first line. be able to. When the dot count unit 63 counts the number of the fourth bits, it outputs the number to the CPU.

Next, the decompression unit 60 reads the difference information of the second line from the RAM 12 and decompresses the compression by the run length method.
Next, the decompressing unit 60 generates line data of the second line by applying the difference represented by the difference information of the second line to the stored line data of the first line.

Next, the decompression unit 60 outputs the generated line data to both the SRAM 61 and the dot count unit 63 while storing the generated line data of the second line.
When the line data of the second line is output, the dot count unit 63 outputs the number of dots formed by the second line, the number of third bits, and the fourth as in the case of the line data of the first line. The number of bits is counted and the counted number is output to the CPU.

Next, the decompression unit 60 outputs the difference information of the second line to the dot count unit 63.
When the difference information is output, the dot count unit 63, based on the output difference information, forms a dot at a bit in the same position of the line data of the first line, and a bit at which a dot is not formed at the second line ( An example of the first pixel (hereinafter referred to as “first bit”) is counted. The number of first bits can be counted by counting the number of difference values having a value of 0 from the difference information. When the dot count unit 63 counts the number of first bits, it outputs the number to the CPU.

  Next, based on the output difference information, the dot count unit 63 generates a bit (second pixel) in which a dot is not formed in the bit at the same position in the line data of the first line but a dot is formed in the second line. For example, hereinafter referred to as “second bit”). The number of second bits can be counted by counting the number of difference values having a value of 1 from the difference information. When the dot count unit 63 counts the number of second bits, it outputs the number to the CPU.

  The controller 53 repeats the same process as the process for the difference information on the second line for the remaining difference information stored in the RAM 12, so that the number of dots and the number of the first to fourth bits for each line. Count.

When the CPU outputs the number of dots and the number of first to fourth bits for all lines from the decompression unit 60, the CPU calculates a toner adhesion amount that is the amount of toner adhered to the paper 3 by printing for one page. presume. Specifically, the CPU adds the total number of dots counted for each line for all lines to d, the total number of first bits counted for each line for all lines, m, The total number of the second bits counted for each line is summed for all lines, n is the total number of the third bits counted for each line is summed for all lines, and the fourth number is counted for each line. When the total number of the total number of bits for all lines is q, the toner adhesion amount is estimated by the following equation 1.
Toner adhesion amount = d × coefficient A + m × coefficient C + n × coefficient D + p × coefficient E + q × coefficient F Formula 1
Here, the coefficient A indicates the amount of toner adhering in the area for one dot. This toner amount does not include the amount of toner that protrudes from the region of one dot out of the toner amount used to form one dot.

  The coefficient C indicates the amount 92 of toner that protrudes downward from the region 73 for one dot (toner that protrudes from the previous line to the target line side) out of the toner used for forming one dot in FIG. 4A. The coefficient D indicates the amount 91 of toner that protrudes upward (toner that protrudes from the target line to the immediately preceding line), the coefficient E indicates the amount 93 of toner that protrudes on the left side, and the coefficient F indicates the amount 94 of toner that protrudes on the right side.

  The coefficients C to F may be the same value or different values. For example, if the amount of toner protruding to the upper side, the amount of toner protruding to the lower side, the amount of toner protruding to the left side, and the amount of toner protruding to the right side are the same or are considered to be the same, the coefficient C˜ F has the same value.

(6) Effects of the Embodiment According to the printer 1 according to the first embodiment of the present invention described above, the dot count unit 63 uses the line orthogonality of the line data of the previous line among the bits constituting the line data of the target line. The number of bits (the number of first bits and the number of second bits) that differ in the presence or absence of dot formation between bits located at the same position in the direction is counted based on the difference information of the target line. For this reason, the dot count unit 63 only needs to store the difference information for one line at a time, and simultaneously stores line data for a plurality of lines in order to count the number of first bits and the number of second bits. You don't have to do that. Thereby, the circuit scale of the dot count part 63 can be reduced. Therefore, according to the printer 1, the toner adhesion amount can be estimated while suppressing an increase in circuit scale.

  Further, according to the printer 1, the toner amount is estimated using the above-described equation 1. In Formula 1, the coefficients C to F corresponding to the amount of toner that protrudes upward, the amount of toner that protrudes downward, the amount of toner that protrudes to the left side, and the amount of toner that protrudes to the right side can be set individually. Regardless, the amount of toner adhesion can be estimated more accurately than when the same coefficient is applied uniformly.

  Furthermore, according to the printer 1, since the dot count unit 63 does not have to store line data for a plurality of lines for counting at the same time, the dot count unit 63 has a bus band of a transfer path for transferring data for counting to the dot count unit 63. I can afford. For example, when line data for a plurality of lines is transferred, the bus band is narrowed and the transfer speed is lowered. On the other hand, according to the printer 1, line data for a plurality of lines need not be stored at the same time. Therefore, the bus bandwidth of the transfer path for transferring the data for counting to the dot count unit 63 can be afforded, and the transfer speed can be increased. Reduction can be suppressed.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

(1) In the above-described embodiment, the case where the toner adhesion amount is estimated by Expression 1 is described as an example, but may be estimated by Expression 2 shown below.
Toner adhesion amount = d × coefficient A + s × coefficient B Formula 2
Here, s is the sum of the total number m of the total number of first bits counted for each line for all lines and the total number n of the total number of second bits counted for each line for all lines. Is a number. In other words, when the amount of toner protruding upward and the amount of toner protruding downward are substantially the same, the first bit and the second bit need not be distinguished and counted.

  Further, Expression 2 is an expression that does not include the third bit number p and the fourth bit number q. In other words, when Expression 2 is used, the amount of toner that protrudes to the left or right side due to dots being formed on the same line is not considered. When the amount of toner that protrudes in the left-right direction is negligible compared to the amount of toner that protrudes in the vertical direction, the amount of toner adhesion can be estimated with a simpler configuration by using Equation 2.

If the amount of toner that protrudes upward is different from the amount of toner that protrudes downward, the toner adhesion amount may be estimated by the following equation 3.
Toner adhesion amount = d × coefficient A + m × coefficient C + n × coefficient D Formula 3

  (2) In the above embodiment, when a dot is formed in the previous line and a dot is not formed in the target line, 0 is set as a difference value, and a dot is not formed in the previous line and a dot is formed in the target line. In the above description, the case where 1 is set as the difference value has been described as an example, but 0 and 1 may not be distinguished, and only the bit number may be stored. In this case, the bit in which the bit number is stored means that the dot on the previous line is the same as the dot on / off state. Therefore, when a dot is formed on the previous line, no dot is formed on the target line. In the case where dots are not formed on the immediately preceding line, dots may be formed on the target line.

  (3) In the above embodiment, the amount of toner that protrudes upward in the first line and the amount of toner that protrudes downward in the final line are not considered, but the toner adhesion amount may be estimated in consideration of these. In that case, the number of dots in the first line may be added to the number of second pixels, and the number of dots in the last line may be added to the number of first pixels.

  (4) In the above embodiment, the case where halftone data is generated by a printer driver executed on a personal computer has been described as an example. However, the printer 1 may generate halftone data from a page to be printed. .

  (5) Although the monochrome printer 1 has been described as an example of the image forming apparatus in the above embodiment, the image forming apparatus may be a color printer having two or more colors. In that case, the toner adhesion amount is estimated for each toner color. The image forming apparatus is not limited to a laser printer, and may be, for example, an LED printer. In addition, the present invention may be applied not only to a printing apparatus such as the printer 1 but also to a multifunction machine having a facsimile function, a printer function, and a reading function (scanner function).

DESCRIPTION OF SYMBOLS 1 ... Laser printer 10 ... Main body case 20 ... Control part 30 ... Feeder part 40 ... Image formation part 53 ... Controller 60 ... Decompression part 62 ... Data output part 63 ... Dot count section

Claims (4)

An image forming apparatus that forms an image on the recording medium by forming dots of color material on the recording medium based on line data representing a dot pattern for one line,
Storage means for storing difference data representing the difference between the line data of the reference line and the line data of the immediately preceding line for each line after the reference line;
For each line after the reference line, generating means for generating line data of the line by applying the difference of the line to the line data of the immediately preceding line;
First counting means for counting the number of dots formed on the recording medium based on line data of each line;
For each line after the reference line, of the pixels constituting the line data of the line, pixels having different dot formation from the pixels at the same position in the line orthogonal direction of the line data of the immediately preceding line Second counting means for counting a number based on the difference information of the line;
Based on the number of dots counted by the first counting means and the total number of pixels counted for each line by the second counting means, the color material adhering to the recording medium An estimation means for estimating the amount of adhesion;
An image forming apparatus comprising: The image forming apparatus according to claim 1,
The estimation means has d as the number of dots counted by the first counting means, and s as the total number of pixels counted for each line by the second counting means. An image forming apparatus that estimates the amount of adhesion using Equation (1).
Adhesion amount = d × coefficient A + s × coefficient B Equation 1 The image forming apparatus according to claim 1,
The second counting means is in the same position as the number of first pixels in which dots are formed in the pixels at the same position of the line data of the immediately preceding line and dots are not formed in the line, and the line data of the immediately preceding line. Each pixel counts the number of second pixels where dots are not formed in the line and dots are formed in the line,
The estimation means is d for the number of dots counted by the first counting means, m for the total number of the first pixels counted for each line by the second counting means, and the second An image forming apparatus that estimates the amount of the color material attached by Equation (2), where n is the total number of pixels.
Adhesion amount = d × coefficient A + m × coefficient C + n × coefficient D Equation 2 The image forming apparatus according to claim 3, wherein
Based on the line data of each line, on the same line, the number of third pixels representing dots that are not formed by adjoining other dots of the line on one side of the line direction, and the other side of the line direction Third counting means for counting the number of fourth pixels representing dots that are not formed adjacent to other dots of the line,
When the total number of the third pixels counted for each line by the third counting unit is p and the total number of the fourth pixels is q, the estimation unit is the color material. An image forming apparatus that estimates the adhesion amount of
Adhesion amount = d × coefficient A + m × coefficient C + n × coefficient D + p × coefficient E + q × coefficient F

Images