JPH11219072A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the device which can form a color image by adjusting optimum image formation conditions in color mode and shorten an output time in monochromatic mode by determining adjustment items of the image formation conditions according to which of the color mode and monochromatic mode the image forming device is in. SOLUTION: An arithmetic unit 57 is provided with a mode discrimination means 57a which decides the color mode wherein color images are formed and the monochromatic mode wherein monochromatic images are formed and a condition determining means 57b which determines adjustment items of the image formation conditions according to the mode decision result of the mode discrimination means 57a. When image formation is started on this device, the arithmetic unit 57 judged whether or not a request signal in a nonvolatile memory is ON. When the request signal is ON, the mode decision means 57a discriminates which of the color mode and monochromatic mode (one black color) the mode of the image formation is. When the color mode is decided, the image formation conditions are adjusted prior to the image formation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for setting image forming conditions when forming a color image or a monochromatic image.

[0002]

2. Description of the Related Art Conventionally, there have been disclosed many techniques for adjusting image forming conditions at a predetermined timing in order to form a predetermined image under optimum image forming conditions. For example, Japanese Unexamined Patent Publication
In JP-A-119371, the image forming conditions are adjusted when a predetermined time has elapsed without performing the image forming operation of the image forming apparatus.

In Japanese Patent Application Laid-Open No. Hei 4-267273, when the power of the image forming apparatus is turned on, the temperature of the fixing roller is detected, and if the detected temperature is lower than a predetermined temperature, image stabilization control is performed. Like that.

Further, in Japanese Patent Application Laid-Open No. Hei 7-104535, the charging output is feedback-controlled based on the density of a reference patch formed on a photosensitive drum immediately before the start of a copying operation.

[0005]

However, in each of these prior arts, the same adjustment is performed irrespective of the image forming mode of the color mode for forming a color image or the single color mode for forming a single color image. For this reason, in the condition adjustment in color image formation, since the adjustment is performed for each color, the adjustment time is long, and even in the case of the single color mode in which short-time print output is required, a long adjustment time is required. This causes output delay.

[0006]

SUMMARY OF THE INVENTION The present invention is an image forming apparatus made to solve such a problem. That is, the image forming apparatus of the present invention includes a mode discriminating unit that discriminates between a color mode for forming a color image and a single color mode for forming a monochromatic image, and an image according to a mode discrimination result by the mode discriminating unit. Image forming condition determining means for determining an adjustment item of the forming condition.

In this image forming apparatus, the mode determining means determines whether the image formation is in the color mode or the single-color mode. Is determined, only items necessary for each mode can be adjusted.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image forming apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of a color copying machine which is an embodiment of the image forming apparatus of the present invention.

As shown in FIG. 1, a color copying machine 1 according to this embodiment is roughly divided into a scanner section 2 for reading an image of a document placed on a document table, and an image for processing the read image data. A processing unit 3; a ROS (Raster Output Scanner) optical unit 4 for driving a laser according to the processed image data to irradiate the photoconductor 50 with a light beam;
And an image forming unit 5 for forming an image.

Around the photoreceptor 50 of the image forming section 5, a charging device 51, an electrometer 52 for measuring the potential of the photoreceptor surface, a rotary developing device 53, a transfer device 54, and a cleaner device 55 along the rotation direction. And a discharge lamp 56 are arranged in order. The rotary developing device 53 includes a toner dispensing device 53a that supplies toner images of each color of Bk (black), Y (yellow), M (magenta), and C (cyan) to corresponding developing devices of the rotary developing device. Is provided.

The transfer device 54 has a configuration in which a transfer corotron 54b, a charge removing corotron 54c, a peeling corotron 54d, and the like are arranged along a transfer drum 54a. (Not shown), the toner image formed on the photoconductor 50 is transferred.

Further, a fixing device 7 is disposed below the transfer device 54 in the sheet conveyance direction so as to fix the toner image transferred to the sheet. The fixing device 7 has a temperature detector T for detecting the temperature of the fixing roller.
S is provided.

Next, the function of each part of the color copying machine will be described with reference to the block diagram of FIG. First, in the scanner section 2, the original is irradiated with the exposure lamp L, and the reflected light is read by the CCD 21 and amplified by the amplifier 22 to an appropriate level. Thereafter, the A / D converter 23 converts the digital image data into 8-bit or 10-bit digital image data.

After the shading correction unit 24 and the gap correction unit 25 perform predetermined correction on the image data, the density converter 26 converts the reflectance data into density data.
The converted image data is sent to the image processing unit 3.

The image processing section 3 performs basic image processing as a color copying machine, that is, color signal conversion, black reproduction (UC
R), MTF processing, etc., to generate image data of four colors of Y (yellow), M (magenta), C (cyan), and B (black). That is, the color signal conversion unit 31 performs color conversion,
Next, the scanner unit 2 and the image forming unit 3 in the gamma correction unit 32
The gradation conversion of each color is performed in accordance with the gradation characteristics of the above.

The image data is converted into analog data by a D / A converter 33, and is output by a comparator 34 to a triangular wave generator 35.
The signal is compared with a signal of a predetermined period sent from the controller and pulse width modulation is performed to perform binarization.

In the patch signal generating means 36, in a mode for setting image forming conditions (hereinafter referred to as "image forming condition setting mode"), a plurality of reference patch image signals having different densities, which are patches for controlling image density, are output. Occur. Further, the selector 37 selects one of the image data converted into analog data by the D / A converter 33 and the patch image signal generated by the patch signal generating means 36 and sends the selected signal to the comparator 34.

The selector 37 selects analog image data during normal copying, and in the image forming condition setting mode, issues a patch creation instruction from the arithmetic unit 57 of the image forming unit 5 and sends a patch image signal from the patch signal generating means 36. Is selected, a patch image signal is selected.

The ROS optical section 4 includes a laser light quantity varying device 41 which is controlled by the arithmetic unit 57 of the image forming section 5 and varies the laser light quantity, and a laser drive circuit 42. The laser driving circuit 42 is a comparator 34 of the image processing unit 3.
ON the laser 43 based on the binary data sent from
/ OFF control.

The laser light is deflected by a polygon mirror 44 and guided to a photoreceptor 50 of an image forming section via a fi lens 45 and a reflection mirror 46.

Around the photoreceptor 50 of the image forming section 5, a charging device 51, an electrometer 52, a rotary developing device 53, a transfer device 54, a cleaner device 55, and a neutralization lamp 56
Are arranged in order. The electrometer 52 measures the potential on the photoconductor 50 in order to control the photoconductor potential.

The optical sensor S detects the density of the patch transferred onto the belt B of the intermediate transfer device 56, and the arithmetic unit 57 controls image forming conditions according to the output of the electrometer 52 and the optical sensor S.

The arithmetic unit 57 discriminates between a mode for forming a color image (hereinafter, referred to as "color mode") and a mode for forming a single color image (hereinafter, referred to as "monochromatic mode"). A mode determining unit 57a and a condition determining unit 57b that determines an adjustment item of an image forming condition according to a mode determination result by the mode determining unit 57a are provided.

The charge amount varying device 58 changes the charge amount of the charging device 51 under the control of the arithmetic device 57. Further, the developing bias variable device 53b changes the developing bias.

FIG. 3 is a diagram for explaining binarization of image data by pulse width modulation in the comparator 34 (see FIG. 2). That is, the input analog image data is compared with a triangular wave, and a portion where the analog image data is larger than the triangular wave is set to "0" to turn off the laser, and a portion where the analog image data is small is set to "1" and the laser is turned on. The data is sent from the comparator 34 to the ROS optical unit 4 as data.

In the color copying machine 1 having such a configuration, an image is formed according to a well-known xerographic process. That is, first, the rotating photoconductor 50 is uniformly negatively charged by the charging device 51, and a first color latent image is formed on the surface of the photoconductor 50 by the laser beam.

In the portion of the latent image written by the laser beam, the first color (Bk:
The negatively charged black toner is developed by the developing device of (black). Next, the developed image is transferred from the sheet tray 8 by the sheet transfer device 6 to a sheet (not shown) wound around the transfer drum 54a and transferred by the transfer corotron 54b.

At this time, the image remaining on the photoreceptor 50 without being transferred is removed by the cleaner device 55 and the photoreceptor 50 is removed.
Is discharged by the discharge lamp 56. Next, the photoconductor 50 is uniformly negatively charged again by the charging device 51, and the image formation of the second color (Y: yellow) is performed in the same manner as the first color.

The third color (M: magenta), the fourth color
Developed images of four colors up to the color (C: cyan) are transferred to transfer drum 54
a is sequentially transferred to the sheet on a. After the transfer, the sheet is peeled off from the transfer drum 54a by the peeling corotron 53d and is fixed by the fixing device 7 to complete the color copy. Also,
A static elimination corotron 54c is arranged around the transfer drum 54a, and removes extra charges on the sheet and the transfer drum 54a after the transfer of each color or after the sheet is separated.

In the color copying machine 1 according to the present embodiment,
It is characterized in that the mode determining means 57a of the arithmetic unit 57 determines whether the mode is the color mode or the single-color mode, and the condition determining means 57b determines the adjustment items of the image forming conditions according to the determination result.

Here, the overall flow in setting the image forming conditions will be described with reference to the flowchart of FIG. In the following description, reference numerals not shown in FIG. 4 refer to FIG.

In setting the image forming conditions, the target dark potential VHS, the target halftone potential VMS,
The arithmetic unit 57 stores the fog prevention potential difference VC from the target dark potential VHS to the developing bias potential VB, the reference grid potentials VG1, VG2, and the reference laser light amounts LD1, LD2.

First, the computing device 57 sets the grid voltage of the charging device 51 to VG1 and VG2 by the charging amount varying device 58, and the dark potentials VH1 and VH2 at this time are measured by an electrometer 52.
(Step S101).

Next, a grid voltage VGS for obtaining the target dark potential VHS is calculated by the arithmetic unit 57 by two-point linear approximation using the dark potentials VH1, VH2 and the grid voltages VG1, VG2 (step S102).

Next, the photosensitive member 50 is charged to a grid voltage VGS obtained by calculation, and the selector 37 of the image processing section 3 is charged.
Then, a reference patch signal from the patch signal generation means 36 is selected, and the binary signal obtained by sending the reference patch signal to the comparator 34 and comparing with the triangular wave is sent to the laser drive circuit 42 of the ROS optical unit 4. The laser light quantity varying device 41 drives the laser drive circuit 42 with two kinds of laser light quantities LD1 and LD2, and creates a patch of a reference patch signal by the two kinds of laser light quantities LD1 and LD2 on the photoconductor 50. , Each of the reference patch potentials VL1, VL2 is detected by the electrometer 52 (step S103).

Next, the laser beam amount LDS for obtaining the target reference patch potential VLS is calculated by the arithmetic unit 57 into the reference patch potential VLS.
Calculation is performed by two-point linear approximation using L1, VL2 and reference laser light amounts LD1, LD2 (step S104).

Then, the developing bias potential VB is calculated by subtracting the fog prevention potential difference VC from the target dark potential VHS, and the developing bias VB is set by the developing bias variable device 53b (step S105).

Next, using the grid voltage VGS, the laser light amount LDS, and the developing bias potential VB, a patch is created again by the reference patch signal, and the patch is developed and the density is measured by the optical sensor S. Thereafter, toner supply is controlled in accordance with the measurement result (step S10).
6).

After the image forming conditions have been adjusted in the processing of steps S101 to S106, these grid voltages V
An image is formed using the GS, the laser light amount LDS, and the developing bias VB. During the image formation, a reference patch is periodically developed, the density is measured by the optical sensor S, and toner supply is controlled (step S107). ).

Next, a procedure for adjusting image forming conditions based on mode determination, which is a feature of the present embodiment, will be described with reference to the flowchart of FIG. In the following description, FIG.
Reference numerals shown in FIG. 2 refer to FIG.

First, when the power of the image forming apparatus (color copying machine) is turned on (step S201), the arithmetic unit 57 is operated.
Detects the temperature Temp of the fixing device 7 by the temperature detector TS (step S202).

Next, this temperature Temp and a predetermined temperature TH
is compared with temp (step S203), and the temperature Temp is compared.
When p is lower than the temperature THtemp, it is assumed that image formation has not been performed for a long time, and the request signal in the nonvolatile memory indicating that adjustment of image forming conditions is necessary is turned on (step S204). On the other hand, the temperature Temp
Is not lower than the temperature THtemp, the image formation is started as it is.

Next, when image formation is started (Yes in step S205), the arithmetic unit 57 determines whether or not the request signal in the nonvolatile memory is ON (step S206). If the request signal is ON, the image forming condition adjustment processing shown in steps S207 to S209 is performed. On the other hand, if the request signal has not been turned ON, image formation is immediately executed (step S210).

If the request signal is ON, the mode determining means 57a determines whether the image forming mode is the color mode or the single-color mode (here, one color of black) (step S207). If it is determined that the color is black, the image formation is executed immediately without adjusting the image formation conditions (step S210).

On the other hand, if it is determined that the mode is the color mode, the image forming conditions are adjusted prior to the image formation (step S208). As the adjustment of the image forming conditions, steps S101 to S106 shown in FIG. 4 are executed. Then, after adjusting the image forming conditions, the request signal in the nonvolatile memory is turned off (step S2).
09), full-color image formation is executed (step S210).

By such processing, in the color mode, the image forming conditions can be adjusted to form an optimal full-color image, and in the single-color mode, the time until print output can be shortened. In addition,
In the single-color mode, the adjustment accuracy of the image forming conditions is not high as compared with the case of the color mode. Therefore, even if the image forming conditions are not adjusted, the influence on the image quality can be reduced.

Next, another embodiment of the present invention will be described.
In another embodiment, in the case of the color mode, all the adjustments of the image forming conditions are performed, and in the case of the single color mode, only the portion of the adjustment of the image forming conditions which does not take much time is performed.

The procedure for adjusting the image forming conditions in another embodiment will be described below with reference to the flowchart of FIG. In the following description, reference numerals not shown in FIG.
Shall be referred to.

First, when the power of the image forming apparatus (color copier) is turned on (step S301), the arithmetic unit 57 is operated.
Detects the temperature Temp of the fixing device 7 by the temperature detector TS (step S302).

Next, the temperature Temp and the predetermined temperature TH
is compared with temp (step S303), and the temperature Tem is compared.
When p is lower than the temperature THtemp, the request signals 1 and 2 in the non-volatile memory indicating that the image forming conditions need to be adjusted assuming that image forming has not been performed for a long time and the image forming conditions need to be adjusted are turned ON (step S304). On the other hand, if the temperature Temp is not lower than the temperature THtemp, the image formation is started as it is.

Next, when image formation is started (Yes in step S305), the arithmetic unit 57 determines whether or not the request signal 2 in the nonvolatile memory is ON (step S306). If the request signal 2 has not been turned ON, image formation is immediately performed (step S31).
0).

On the other hand, if the request signal 2 is ON, the mode determining means 57a determines whether the image forming mode is the color mode or the single-color mode (here, one color black) (step S307). . If it is determined that the mode is the color mode, all the adjustments of the image forming conditions are executed prior to the image formation (step S30).
8). As the adjustment of the image forming conditions, steps S101 to S106 shown in FIG. 4 are executed.

After adjusting the image forming conditions,
The request signals 1 and 2 in the non-volatile memory are turned off (step S309), and full-color image formation is executed (step S310).

On the other hand, if it is determined that the mode is the monochrome mode,
It is determined whether or not the request signal 1 in the non-volatile memory is ON (step S311). If the request signal 1 is not ON, image formation is performed immediately (step S31).
0). If the request signal 1 is ON, a part of the adjustment of the image forming conditions is executed prior to the image formation (step S312).

As a part of the adjustment of the image forming conditions,
For example, only the potential-related adjustment in steps S101 to S105 shown in FIG. 4 is performed. In other words, while the adjustment in steps S101 to S105 is about 1.5 seconds for one rotation of the photoconductor 50, the development-related adjustment in step S106 requires about 12 seconds for eight rotations of the photoconductor 50. For this reason, in the case of the monochromatic mode, only the potential-related adjustment which does not take much time is performed.

After performing this adjustment, the request signal 1 in the nonvolatile memory is turned off (step S313),
Image formation is performed (step S310).

According to the processing in the other embodiment, in the color mode, all adjustments of the image forming conditions are performed to form an optimal full-color image, and in the single-color mode, printing can be performed by only the adjustment which does not take much time. It is possible to shorten the time until output.

In each of the embodiments described above, the example of one black color is used as the single color mode, but the same applies to a single color other than one black color.

[0059]

As described above, the image forming apparatus according to the present invention has the following effects. That is, by determining the adjustment items of the image forming conditions according to whether the image formation is the color mode or the single color mode, in the case of the color mode, it is possible to form a color image by adjusting the optimal image formation conditions, In the case of the monochromatic mode, it is possible to shorten the output time.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a color copying machine according to an embodiment.

FIG. 2 is a block diagram of a color copying machine.

FIG. 3 is a diagram illustrating pulse width modulation.

FIG. 4 is an overall flowchart in setting image forming conditions.

FIG. 5 is a flowchart illustrating a procedure for adjusting image forming conditions based on mode determination.

FIG. 6 is a flowchart illustrating an adjustment procedure according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Color copier, 2 ... Scanner part, 3 ... Image processing part, 4 ... ROS optical part, 5 ... Image forming part, 6 ... Paper conveying device, 7 ... Fixing device, 8 ... Paper tray, 57 ... Computing device, 57a: mode determining means, 57b: condition determining means

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 15/08 115

Claims (3)

[Claims] 1. A mode discriminator for discriminating between a color mode for forming a color image and a single color mode for forming a monochromatic image, and an adjustment item for image forming conditions according to a result of the mode discrimination by the mode discriminator. An image forming apparatus comprising: an image forming condition determining unit for determining the image forming condition. 2. The image forming apparatus according to claim 1, wherein the image forming condition determining unit executes the adjustment of the image forming condition only when the mode determining unit determines that the color mode is set. . 3. The image forming condition determining means adjusts a charging condition of the image carrier and forms a latent image on the image carrier when the mode discriminating means determines the monochrome mode. The light source condition adjustment and the development condition adjustment are performed, and when it is determined that the color mode is set, the charging condition of the image carrier is adjusted and the latent image is formed on the image carrier. 2. The image forming apparatus according to claim 1, wherein a condition of a light source is adjusted, a condition of a developing condition is adjusted, and a toner replenishment control is performed based on a density measurement of a reference patch developed on the image carrier under the developing condition.