JP2972778B2 - Recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a recording device such as an electrophotographic recording device and a thermal recording device for recording an image in accordance with image data.

(Prior art) A laser printer, which is a type of recording device, scans a photoreceptor surface with laser light emitted from the laser diode while controlling light emission / non-light emission by a laser diode according to image data. Perform an exposure operation.

Here, as shown by S1 in FIG. 9, the image data is a signal which becomes “H” or “L” level over the entire area of each scanning period T1 for _one pixel. Conventionally, as shown by S2 in FIG. 9, the drive signal of the laser diode uses the timing of the image data S1 as it is. Therefore, control of the light emission / non-emission of the laser diode is performed scan period T ₁ of the one pixel as a unit, the laser diode emits light for a period in the entire region of the T ₁ is the time of emission.

Incidentally, the electric resistance of the photoreceptor changes according to the amount of incident light, and therefore, the amount of charge decay changes according to the incident time of light. And the drive signal as described above
When the laser diode is driven in S2, a pixel as shown in FIG. 10A is formed. Here, a circular area indicated by oblique lines is a pixel to be recorded, and a square area indicated by a broken line is an area of one pixel.

Thus, when the laser diode emits light over the entire duration of the scan T ₁ of the one pixel, it is possible to record the pixels covering all the pixel regions, according to the pixel, the
(10) A solid black image as shown in FIG. (B) can be recorded without gaps, and a good solid black density can be obtained. However, for example, when printing an image to which a Bayer-type dither or the like is applied, if, for example, an attempt is made to obtain a recording pattern as shown in FIG. 10 (c), it will extend beyond the one pixel area shown in FIG. 10 (a). If the pixel is a defective pixel, good tone reproduction cannot be performed. Also, when recording fine characters or the like, crushing or the like occurs.

The drive signal of the laser diode is shown in FIG.
Signal, as shown in it is considered to be a short time period T ₂ than the scanning period T ₁ of the one pixel period becomes "H" level. In this way, for example, as shown in FIG. 11 (a), the pixels fall within one pixel area, and when an image to which a Bayer type dither or the like is applied is recorded, as shown in FIG. 11 (b). A recording pattern can be obtained, and good halftone reproduction can be performed. However, in this case, when a solid black image is recorded, a gap is generated between pixels as shown in FIG. 11 (c), and a sufficient solid black density cannot be obtained.

The disadvantages described above also apply to other electrophotographic recording devices such as light emitting diode (LED) printers and liquid crystal (LCD) printers, thermal recording devices such as thermal printers and thermal transfer printers, ink jet recording devices or electrostatic recording devices. It is.

(Problems to be Solved by the Invention) As described above, in the conventional recording apparatus, pseudo halftone (dither and the like) images formed by discretely arranged pixels and images such as characters are intensively arranged. It has been difficult to satisfactorily record both an image such as a solid black image formed by the pixels.

The present invention has been made in view of such circumstances, and an object of the present invention is to satisfactorily reproduce both an image such as a pseudo halftone image or a character and an image such as a solid black image. An object of the present invention is to provide a recording apparatus capable of favorably recording both images even if both images are mixed in one image.

[Configuration of the Invention] (Means for Solving the Problems) According to the present invention, pixels are formed by pixel forming means in accordance with image data which is an array of pixel data indicating formation / non-formation of pixels. In a recording apparatus that performs recording, a pixel size setting signal such as a light emission time setting signal or 3-bit data indicating the size of a pixel formed in accordance with the pixel data of interest with respect to the pixel data of interest in the image data For example, in a data table such as a light emission time setting unit and a conduction time setting unit, output according to the state of predetermined pixels arranged in the vertical direction of the pixel indicated by the target pixel data, and output each pixel of the image data. When forming a pixel according to data, a pixel having a pixel size indicated by a pixel size setting signal output for each pixel data by the pixel size setting means is formed. Ku, and to control the pixel-forming means so as to vary the formation energy amount for performing formation time or a pixel formation effect formation of one pixel, for example.

(Operation) By taking such means, the arrangement of pixels, that is, the degree of concentration is identified based on the image data, and the formation time or the recording time of each pixel is recorded in accordance with the degree of concentration of the identified pixels. The amount of formation energy is changed and set.

Therefore, the size of each pixel is changed according to the degree of concentration of the pixel, and a pixel having a size as required is recorded as appropriate.

First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a main configuration of a laser printer configured by applying the recording apparatus according to the present invention. This laser printer includes an interface unit 1, a control unit 2, an image memory 3, shift registers 4a, 4b, 4c, a light emission time setting unit 5, a laser scanner unit (hereinafter referred to as LSU) 6, and a photosensitive drum 7. It is composed.

The interface unit 1 fetches image data from the outside of the apparatus (not shown) or another part inside the apparatus (for example, the laser printer is applied to a recording unit of a facsimile apparatus, but in this case, it corresponds to a transmission / reception apparatus). The image data captured by the interface unit 1 is stored in the image memory 3 via the control unit 2. The image memory 3 is a memory capable of storing at least one page of image data. The image data stored in the image memory 3 is stored in the control unit 2 each time one page of image data is accumulated.
Are sequentially read and input to the shift register 4a.

Each of the shift registers 4a to 4c performs a shift operation using the clock of the image data as a transfer clock. Each of the shift registers 4a to 4c has the same number of bits as the pixel data included in the image data for one line. The shift registers 4a to 4c are connected in series so that the output of the shift register 4a is input to the shift register 4b and the output of the shift register 4b is input to the shift register 4c. Accordingly, respective outputs Q _A, Q _B, Q _C of each shift register 4a~4c is continuous pixels at the same position in the main scanning direction (lateral direction) of the three successive lines, i.e. in the sub scanning direction This is pixel data of three pixels.

The luminous time setter 5 will comprise, for example, the ROM (not shown), the respective outputs Q _A of the shift register 4 a to 4 c, Q _B, Q _C
In response to this, from these output states, three consecutive pixels in the sub-scanning direction centering on the pixel to be recorded (the pixel corresponding to the pixel data output from the shift register 4b).
An arrangement state of the two pixels is identified, and a light emission time setting signal SA corresponding to the arrangement state is output to the LSU6.

The LSU 6 is rotated at a predetermined speed by a laser diode 62 that emits a laser beam 61, a collimator lens 63 that uses the laser beam 61 emitted from the laser diode 62 as light having a predetermined diameter, and a polygon motor 64 to expose the laser beam 61 to light. A polygon mirror 65 for scanning the photosensitive surface of the drum 7, an f-θ lens 66 for scanning the laser beam 61 reflected by the polygon mirror 65 on the photosensitive surface of the drum 7 at a constant speed, and a shift register
Laser diode according to image data SB output from 4b
A light emission drive section 67 that generates a drive signal SC for driving 62
Consists of The light emission drive unit 67 is configured to output a laser diode based on the light emission time setting signal SA output from the light emission time setting unit 5.
It has a function of variably controlling the light emission time of 62. In addition, although not shown in the figure around the photosensitive drum 7, charging,
An apparatus for performing processes other than exposure in the electrophotographic system such as development, transfer, fixing, cleaning, and static elimination is arranged, and constitutes an electrophotographic recording apparatus of a reversal development system.

Next, the operation of the laser printer configured as described above will be described. First, at the time of the recording operation, the image data stored in the image memory 3 is sequentially read by the control unit 2 and input to the shift restor 4a. The image data input to the shift register 4a is sequentially transferred in the shift register 4a, the shift register 4b, and the shift register 4c. Here, the contents of the shift registers 4a to 4c are cleared in the initial state. Accordingly, when the input of the third line of image data to the shift register 4a is started, the shift register 4b
Output the image data of the first line,
The input of image data to starts.

The light emission drive section 67 controls light emission / non-light emission of the laser diode 62 based on output data of the shift register 4b. In this state, the light emission time setting section 5 performs the following processing. .

The data table shown in FIG. 2 is set in the light emission time setting section 5. The light emission time setting section 5 takes in the respective outputs of the shift registers 4a to 4c as 3-bit data, extracts data corresponding to the data from the data table, and outputs the data as a light emission time setting signal SA as a light emission drive section 67.
Give to That is, the state of three pixels that are consecutive in the vertical direction (sub-scanning direction) extracted by the shift registers 4a to 4c are identified. Then, according to the identified state, A, B, C
One of the three states is selected and determined, and data indicating the selected state is given to the light emission drive section 67 as the light emission time setting signal SA. Here, since the output of the shift register 4b is input to the light emission drive unit 67 as the image data SB,
The light emission time setting unit 5 selects and determines one of three states A, B, and C in a state where the laser diode 62 emits light.

Specifically, when the central pixel of three consecutive pixels in the sub-scanning direction extracted by the shift registers 4a to 4c is "black", the state of the three consecutive pixels is shown in FIG. ) To (d).

That is, as shown in FIG. 3A, only the center pixel is "black".
State.

As shown in FIG. 3 (b), in addition to the central pixel, the pixel of the immediately preceding line (upper pixel in the figure) is in a state of “black”.

As shown in FIG. 3 (c), in addition to the center pixel, the pixel on the next line (the lower pixel in the figure) is "black".

A state where all the pixels are “black” as shown in FIG.

There are four states.

Then, the light emission time setting unit 5 displays the state “A” in the above case, the state “B” in the above or the above case,
In the above case, the state “C” is selected and determined, and this is notified to the light emission drive unit 67 by the light emission time setting signal SA.

In response to this, the light emission drive unit 67, as shown in FIG.
When the state is “A”, it is T _A during one pixel scanning period T ₁ , and when the state is “B”, it is T _B during one pixel scanning period T ₁
Period, and each driving signal SC T _C period of one pixel scanning period T ₁ when the state "C" and "H" level. Here, T _A , T _B , and T _C are arbitrarily set such that the relationship [T _A <T _B <T _C ≦ T ₁ ] is satisfied. In the present embodiment has a [T _C = T _1] for T _C.

Thus, a black pixel independent of one pixel in the sub-scanning direction is exposed for a short light emission time, for example, as shown in FIG.
As shown in (1), a pixel as small as not to touch each side of one pixel area is recorded. In addition, two consecutive black pixels in the sub-scanning direction are exposed at an intermediate light emission time, and for example, pixels inscribed in one pixel area are recorded as shown in FIG. 5B. Further, black pixels that are continuous in three or more pixels in the sub-scanning direction are exposed for a long light emission time, for example, the fifth pixel.
Pixels circumscribing one pixel area as shown in FIG. However, in the case of three or more continuous black pixels in the sub-scanning direction, the pixels located at the upper and lower ends have the same size as in the case of two consecutive pixels.

As a result, in a portion where pixels are discretely arranged, that is, in a region such as a pseudo halftone image such as a Bayer type dither or a character, small pixels that do not protrude from one pixel region are formed. And record delicate characters. In a portion where pixels are arranged intensively, that is, in a region such as a solid black image, a pixel large enough to cover one pixel region is formed, and a sufficient solid black density can be obtained.

In the present embodiment, the state of three consecutive pixels in the sub-scanning direction is recognized. Therefore, even if three or more consecutive black pixels are present, one pixel at each end is determined as two consecutive black pixels. Thus, slightly smaller pixels (pixels that do not protrude from one pixel area) are recorded. That is,
The solid black image is recorded in a state as shown in FIG. 6, but since each pixel at the upper and lower ends is a small pixel that does not protrude from the one pixel area, Visually, the boundary between the solid black image portion and the white background portion clearly appears, and a more ideal recording state can be obtained. Further, according to the present embodiment, since the light emission time setting unit 5 is constituted by a data table, it can be realized with a simple structure without the necessity of assembling a complicated logic. Even when the relationship between the state of the pixel and the pixel size of the pixel of interest is changed, it can be done relatively easily.

Second Embodiment Hereinafter, a second embodiment of the present invention will be described.

FIG. 7 is a diagram showing a main configuration of a thermal printer configured by applying the recording apparatus according to the present invention. This thermal printer includes a head controller 10, an enable signal generation circuit 20, an image data processing unit 30, a head driver 40, and a thermal head 50.

The head controller 10 converts image data output from an external device (not shown) or another portion within the device (for example, the present thermal printer is applied to a recording unit of a facsimile apparatus, but in this case, for example, corresponds to a transmission / reception apparatus). Then, in synchronization with the image data, a timing signal, a latch signal, and a clock signal for generating an enable signal are generated.

The enable signal generation circuit 20 includes the head controller 10
Based on the timing signal generated in step (1), an enable signal described later is generated and supplied to the head driver 40.

The image data processing unit 30 includes shift registers 31a, 31b, 31c,
Energizing time setting section 32, line memory 33 and output control circuit
Consists of 34.

The shift registers 31a to 31c each perform a shift operation using the clock of the image data as a transfer clock. Each of the shift registers 31a to 31c has the same number of bits as the pixel data included in the image data for one line. The shift registers 31a to 31c are connected in series so that the output of the shift register 31a is input to the shift register 31b and the output of the shift register 31b is input to the shift register 31c. Therefore, each shift register 31a
Each output Q _A of ~31c, Q _B, Q _C is the pixel in the same position in the main scanning direction (lateral direction) of the three successive lines, i.e. three consecutive pixels in the sub-scanning direction pixel data It is. The energization time setting unit 32 is composed of, for example, a ROM, and outputs Q _A , Q _B , and Q _{C of the} shift registers 31a to 31c, respectively.
Receiving, and outputs the 3-bit data corresponding to the output Q _A, Q _B, data indicated by Q _C. The line memory 33 stores one line of image data that has been set to 3 bits per pixel by the energization time setting unit 32. The output control circuit 34 causes the data in the line memory 33 to be output as recording data in a procedure described later based on the clock signal and the latch signal output from the head controller 10.

The head driver 40 includes a shift register 41, a latch circuit
, 43-n and switch amplifiers 44-1, 44-2 ..., 44-n.

The shift register 41 is an n-bit shift register (n is the number of pixels in one line of an image to be recorded), transfers and holds the recording data output from the line memory 33, and outputs the data in parallel. Latch circuit 42 is a head controller
Shift register in synchronization with the latch signal output from 10
41 n-bit outputs are captured and held. Latch circuit
The 42 n-bit outputs are AND gates 43-1, 43
-2,..., 43-n. The other input terminal of each of the AND gates 43-1, 43-2,..., 43-n receives the enable signal generated by the enable signal generation circuit 20, and only when this enable signal is at "H" level. The output of the latch circuit 42 is connected to the switch amplifiers 44-1, 44.
-2,..., 44-n. Switch amplifier 44−
, 44-n are respectively connected to the n heating resistors R-1, R-2,..., Rn constituting the thermal head 50, and the input is "H". A drive voltage of +24 V is applied to the corresponding heating resistor only when the level is at the level.

Next, the operation of the thermal printer configured as described above will be described. First, when image data is input during a recording operation, the head controller 10 captures this image data,
It is provided to the image data processing unit 30. In the image data processing unit 30,
Three pixel data continuous in the sub-scanning direction are extracted and output by the shift registers 31a to 31c. Then, 3-bit data corresponding to the three pixel data output from the shift registers 31a to 31c is output from the energization time setting unit 32. That is, the target pixel data is converted into 3-bit data based on the state of the pixels located at both ends in the vertical direction of the pixel (target pixel) indicated by arbitrary pixel data (hereinafter, referred to as target pixel data). The image data of 3 bits per pixel is stored in the line memory 33. The 3-bit data output from the energization time setting unit 32 is:
For example, it is set as follows.

As shown in FIG. 3 (a), only the central pixel is "black"
State is, i.e. Q _A, Q _B, Q _C are "0",
"001" in the state of "1" and "0".

State (in the upper side in the drawing of the pixel) FIG. 3 (b) 1 one pixel of the previous line as the other center pixel shown in is "black", i.e. Q _A, Q _B, Q _C, respectively "1", "1",
"010" in the state of "0".

Figure 3 state in addition to one behind the line pixels of the center pixel as shown in (c) (the lower side of the pixel in the figure) is "black", i.e. Q _A, Q _B, Q _C is "0", "1",
"010" when it is "1".

Figure 3 state all the pixels as shown in (d) is "black", i.e. Q _A, Q _B, Q _C are "1",
"1", "1" in the state is "100." state central pixel is "white", i.e., in the state Q _B is "0", "000".

When the above processing is performed and the image data of one line is stored in the line memory 33, the output control circuit 34 outputs the image data of each pixel of the image data of one line stored in the line memory 33. Only the first bit (least significant bit) is sequentially output from the line memory 33. The print data output from the line memory 33 in this manner is stored in the head driver 40.
Is entered. The head driver 40 sequentially takes in the input recording data into the shift register 41 (period a in FIG. 8).

On the other hand, the head controller 10 outputs a pulse having a predetermined time width as the latch signal LA after the fetch of the first bit data into the shift register 41 is completed (eighth pulse)
(Pulse shown by b in the figure). Thus, the data held in the shift register 41 is taken into the latch circuit 42 and held.

After the data held in the shift register 41 is captured by the latch circuit 42, the output control circuit 34 determines only the second bit of each pixel data of the image data for one line stored in the line memory 33. Are sequentially output from the line memory 33. The recording data output from the line memory 33 in this manner is stored in the shift register in the same manner as described above.
It is taken into 41 sequentially. (Period c in FIG. 8).

By the way, in the enable signal generation circuit 20, based on a timing signal given from the head controller 10,
A pulse is generated after a predetermined period from the pulse of the latch signal LA. Here, pulses having different pulse widths T _A , T _B , and T _C (T _A <T _B <T _C ) are sequentially output from the enable signal generation circuit 20, that is, a pulse having a pulse width T _A → a pulse width T _B.
It is the output of a pulse ... the order of the pulse → pulse width T _C of the pulse → T _A. That is, the enable signal EN generated by the enable signal generation circuit 20 is a signal as shown in FIG.

First, when a pulse having a pulse width T _A shown in FIG. 8 is output from the enable signal generation circuit 20 as an enable signal, the AND gates 43-1 to 43-1 of the head driver 40 are output.
43-n is ON only during this period of T _A. At this time, among the image data of one line in the latch circuit 42, since the first bit of each pixel data is held, the T _A the data to each of the switch amplifier 44-1 to 44-n Entered only for the period. Thus, the switch amplifiers 44-1 to 44-
n is one of the lines of image data, based on the first bit of each pixel data, the heating resistor for a period of T _A R-1
To R-n.

After that, the fetching of the second bit data into the shift register 41 is completed, and when the pulse indicated by E in FIG. 8 is output from the head controller 10 as the latch signal LA,
The latch circuit 42 captures and holds the data held in the shift register 41. Subsequently, after the data held in the shift register 41 is taken into the latch circuit 42, the output control circuit 34
Only the third bit of each pixel data of the image data of the line is sequentially output from the line memory 33. The recording data output from the line memory 33 in this manner is sequentially taken into the shift register 41 in the same manner as described above (to the period in FIG. 8).

After a slight time pulse indicated by e in FIG. 8 as a latch signal LA from being outputted from the head controller 10, Doo pulse (FIG. 8 pulse width T _B as an enable signal from the enable signal generating circuit 20 Is output. Thereby, the AND gates 43-1 to 43-n
But the ON state only during the period of the T _B. At this time, among the image data of one line in the latch circuit 42, since the second bit of each pixel data is held, this data is T _B to each of the switch amplifier 44-1 to 44-n Entered only for the period. Thus, the switch amplifiers 44-1 to 44-n are
Of the image data of one line, based on the second bit of each pixel data, only the heating resistor period T _B R-1~R-
Control of voltage application to n.

Further, when the third bit of data has been fetched into the shift register 41 and the pulse shown in FIG. 8 as a latch signal LA is output from the head controller 10, the latch circuit 42 is held in the shift register 41. Capture and retain the data

After a slight time pulse indicated by switch in FIG. 8 as a latch signal LA from being outputted from the head controller 10, Li pulse (FIG. 8 pulse width T _C as an enable signal from the enable signal generating circuit 20 Is output. Thereby, the AND gates 43-1 to 43-n
But the ON state only during the period of this T _C. At this time, among the image data of one line in the latch circuit 42, since the third bit of each pixel data is held, from T _C this data to each of the switch amplifier 44-1 to 44-n Entered only for the period. Thus, the switch amplifiers 44-1 to 44-n are
Of the image data of one line, based on the third bit of each pixel data, only the heating resistor period T _C R-1~R-
Control of voltage application to n.

Thereafter, the above processing is repeated for the image data of the lines following the next line.

Here, as described above, the 3-bit data output from the energization time setting unit 32 is “001” when only the central pixel of the extracted three pixels is “black”, and And “010” when any of the pixels above and below is “black”, and “10” when all the pixels are “black”
0 ", and" 000 "if the center pixel is" white "
There is. That is, when only the central pixel among the three extracted pixels is “black”, only the first bit is included, and when the central pixel and one of its upper and lower pixels are “black”, the first bit is extracted. Only two bits, and if all pixels are "black", only the third bit is "1" respectively.
It has become.

Therefore, when only the central pixel among the three extracted pixels is “black”, the central pixel is the heating resistor
It is recorded by heat generated by voltage application T _A period. If any of the pixels of the central pixel and its upper and lower is "black", the central pixels are recorded by heat generated by voltage application of T _B period of the heating resistor. When all the pixels are “black”, the central pixel is recorded by the heat generated by the voltage application of the heating resistor during the _TC period. When the center pixel is “white”, the obtained 3-bit data is “000”, so that no voltage is applied to the heating resistor and no pixel is formed.

Thus, the black pixel independent of one pixel in the sub-scanning direction is exposed for a short energizing time, for example, as shown in FIG.
As shown in (1), a pixel as small as not to touch each side of one pixel area is recorded. In addition, two consecutive black pixels in the sub-scanning direction are exposed during an intermediate energization time, and for example, pixels inscribed in one pixel area are recorded as shown in FIG. 5B. Further, black pixels that are continuous for three or more pixels in the sub-scanning direction are exposed for a long energizing time, for example, the fifth
Pixels circumscribing one pixel area as shown in FIG. However, in the case of three or more continuous black pixels in the sub-scanning direction, the pixels located at the upper and lower ends have the same size as in the case of two consecutive pixels.

As a result, in a portion where pixels are discretely arranged, that is, in a region such as a pseudo halftone image such as a Bayer type dither or a character, small pixels that do not protrude from one pixel region are formed. And record delicate characters. In a portion where pixels are arranged intensively, that is, in a region such as a solid black image, a pixel large enough to cover one pixel region is formed, and a sufficient solid black density can be obtained. Further, according to the present embodiment, since the energization time setting unit 32 is configured by the data table, it is not necessary to form a complicated logic, and can be realized by a simple configuration. Even if the relationship between the state and the pixel size of the target pixel is changed, it can be performed relatively easily.

The present invention is not limited to the above embodiments, and the following modifications can be made.

As described above, when it is inconvenient that each pixel at the upper and lower ends of the solid black image becomes a small pixel, the number of shift registers is increased to, for example, five, and the light emission time setting unit 5 and the conduction time setting unit 32 The range of state identification may be expanded by using.

In each of the above embodiments, the size of the pixel is changed depending on the light emission time and the voltage application time (heat generation time) to the heating resistor. Other elements or a combination thereof may be used.

In each of the above embodiments, the light emission time of the laser diode 62 and the voltage application time of the heating resistors R-1 to R-n are three steps, but may be two steps or four or more steps.

In each of the above embodiments, the recording apparatus according to the present invention is applied to a laser printer and a thermal printer, but may be applied to other electrophotographic recording apparatuses such as an inkjet printer, an LED printer, an LCD printer, and an electrostatic recording apparatus. Is also applicable. At this time, if it is an ink jet printer, the same method as in the first embodiment is suitable.
For other electrophotographic recording devices such as printers and LCD printers and electrostatic recording devices, the same method as in the second embodiment is suitable.

In the first embodiment, the laser printer of the reversal developing system is described as an example. However, if the logic is considered in reverse, the laser printer can be easily applied to the forward developing system.

In addition, various modifications can be made without departing from the spirit of the present invention.

[Effects of the Invention] According to the present invention, there is provided a printing apparatus which performs printing by forming pixels by pixel forming means in accordance with image data which is an array of pixel data indicating formation / non-formation of pixels. For the pixel data of interest in the image data, a pixel size setting signal indicating the size of a pixel formed according to the pixel data of interest is output from a predetermined pixel arranged in the vertical direction of the pixel indicated by the pixel data of interest. A pixel size indicated by a pixel size setting signal output for each pixel data by the pixel size setting means when outputting a data table according to the state and forming a pixel according to each pixel data of the image data The pixel forming means is controlled so as to change, for example, a formation time for forming one pixel or a formation energy amount for forming one pixel in order to form one pixel. As a result, it is possible to record both an image such as a pseudo halftone image or a character and an image such as a solid black image satisfactorily even if both images are mixed in one image. The recording apparatus can be realized with a configuration in which the setting can be easily and flexibly changed.

[Brief description of the drawings]

FIGS. 1 to 6 are views for explaining a first embodiment of the present invention, and FIG. 1 is a view showing a main part configuration of a laser printer constituted by applying the recording apparatus according to the present embodiment. FIG. 2 is a diagram schematically showing a data table set in the light emission time setting unit 5 in FIG. 1, and FIG. 3 explains recognition of a pixel array in the light emission time setting unit 5 in FIG. 4, FIG. 4 is a signal diagram of each part in FIG. 1, FIG. 5 is a diagram showing a recording example of pixels, FIG. 6 is a diagram showing a recording example of a solid black image, FIG. 7 and FIG.
FIG. 7 is a diagram for explaining a second embodiment of the present invention. FIG. 7 is a diagram showing a main part configuration of a thermal printer configured by applying the recording apparatus according to the present embodiment, and FIG. FIGS. 9 to 11 are time charts for explaining the prior art. DESCRIPTION OF SYMBOLS 1 ... Interface part, 2 ... Control part, 3 ... Image memory, 4a, 4b, 4c ... Shift register, 5 ... Emission time setting part, 6 ... Laser scanner unit (LSU), 61 ...
Laser light, 62 laser diode, 67 light emission drive unit, 10 head controller, 20 enable signal generation circuit, 30 image data processing unit, 31a, 31b, 31c shift register, 32 ... energization time setting section, 33 ... line memory, 34 ... output control circuit, 40 ... head driver, 50
... thermal head.

Continued on the front page (72) Inventor Toshihiko Nannichi 3-1-1, Asahigaoka, Hino-shi, Tokyo Inside the Toshiba Hino Plant (72) Inventor Masanori Terasaki 3-1-1, Asahigaoka, Hino-shi, Tokyo Toshiba Inside the Hino Plant (72) Katsumi Murano Inventor, 3-1-1 Asahigaoka, Hino-shi, Tokyo In-house Toshiba Hino Plant (72) Inventor Haruki Kinoshita 3-1-1, Asahigaoka, Hino-shi, Tokyo Toshiba Hino Plant (72) Inventor Masayoshi Aihara 3-1-1 Asahigaoka, Hino-shi, Tokyo Toshiba Hino Factory Co., Ltd. (56) References JP-A-2-274568 (JP, A) JP-A-2-45167 (JP, A) JP-A-1-227573 (JP, A) JP-A-3-47776 (JP, A) JP-A-1-175460 (JP, A) JP-A-3-89776 (JP, A) JP-A-3 -243368 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/52 H04N 1/23

Claims (3)

(57) [Claims] An image forming apparatus for recording an image in which a large number of pixels are two-dimensionally arranged, and in accordance with image data which is an array of pixel data indicating formation / non-formation of pixels. In a printing apparatus that performs printing by forming pixels according to the following, for a target pixel data of the image data, a pixel size setting signal indicating a size of a pixel formed according to the target pixel data is output to the target pixel. A data table to be output according to the state of a predetermined pixel arranged in the vertical direction of the pixel indicated by the data, and when forming a pixel according to each pixel data of the image data, each of the pixels is set by the pixel size setting unit. Pixel forming control means for controlling the pixel forming means so as to form a pixel having the pixel size indicated by the pixel size setting signal output with respect to the pixel data. Recording device. 2. The recording apparatus according to claim 1, wherein the pixel formation control means controls a pixel size by changing a formation time for forming one pixel. 3. The recording apparatus according to claim 1, wherein the pixel formation control means controls the size of the pixel by changing the amount of formation energy for forming one pixel.