JPH10161367A - Image forming device and image density setting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain a hard copy with an optimum image density, at the time of executing both-face recording by setting the density of an image for the both-face recording, based on the result of the discrimination of the light transmittance of a recording medium. SOLUTION: A white and black design (pattern) is recorded on a pattern plate 102, the design of the pattern plate 102 obtained through the transmission of a sheet of paper 104 is scanned by a scanner 101 and the obtained image data is transmitted to an image density control part 103. The relation between the number of erected bits and an image density setting value X is previously decided by an experiment and stored as a table, based on the obtained image data. At this time, in the image density control part, 103, the number of erected bits are detected to obtain the required image density setting value X from the retrieval of the table. When X<=T is obtained with respect to an image density setting value T previously set by the user, the output voltage of a high- voltage circuit 105 is controlled to set the primary potential by electrification of a photoreceptor drum 106, with the image density setting value X.

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 such as a copying machine and a printer, and more particularly to an image density setting for double-sided recording (also referred to as double-sided printing, double-sided copying, and double-sided printing).

[0002]

2. Description of the Related Art Conventionally, the setting of image density during double-sided printing of a page printer is set by the user himself or herself by remote control from a panel or a host computer, based on the experience of the user.

A scanner incorporated in a composite printer or the like is used for copying and facsimile, and an optical sensor is used for detecting paper.

[0004]

In the above-mentioned conventional example, since the user sets the image density of the hard copy by intuition,
During double-sided printing, the recording result on the back side is transmitted to the front side, making it difficult to see.Because all the sheets have the same image density, different images must be used to find a satisfactory image density. There is a problem that it is necessary to output the density.

The present invention has been made under such circumstances, and provides an image forming apparatus and an image density setting method capable of easily obtaining a hard copy having an optimum image density during duplex recording. It is intended for.

[0006]

In order to achieve the above object, according to the present invention, an image forming apparatus is provided as described in (1) to (5) below, and an image density setting method is provided as described in (6) below. To be configured.

(1) Light transmittance determining means for determining the light transmittance of the recording medium, and image density setting means for setting the image density for double-sided printing based on the determination result of the light transmittance determining means. Image forming apparatus.

(2) The image forming apparatus according to (1), wherein the light transmittance determining means has a pattern plate and a scanner arranged so as to sandwich the recording medium.

(3) The image forming apparatus according to the above (1), wherein the light transmittance determining means has a light emitting body and a light receiving body arranged so as to sandwich the recording medium.

(4) Image density setting means for sequentially setting different image densities for one recording medium, and one surface of the recording medium is sequentially moved in one direction based on the density setting by the image density setting means. A plurality of regions having different image densities, and a plurality of regions on the other surface respectively facing the plurality of regions,
An image forming apparatus comprising: a test print forming unit configured to form a test print having the same image density as the image density of one of the opposing surfaces.

(5) The image density is set by controlling the surface potential of the photosensitive member for forming an electrostatic latent image.
The image forming apparatus according to any one of (4).

(6) One surface of the recording medium is defined as a plurality of areas having sequentially different image densities in one direction, and a plurality of areas on the other face respectively opposing the plurality of areas are defined as one face opposing each other. An image density setting method for determining an appropriate image density based on a test print having the same image density as the image density of the area, and setting the determined image density.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to examples of a "printer".

[0014]

【Example】

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a main part of a "printer" which is Embodiment 1. In FIG.
Reference numeral denotes a scanner that scans a sheet (recording medium) 104 conveyed between the pattern plate 102 and reference numeral 103 denotes an image density (also referred to as toner density) control unit that sets an image density based on scanned data. Reference numeral 105 denotes a high voltage circuit whose voltage is controlled by the image density control unit 103.

The pattern plate 102 has white and black patterns (patterns) as shown in FIG. 3A, and the pattern of the pattern plate 102 obtained through the paper 104 is shown in FIG.
Scanning is performed by the scanner 101, and the obtained image data is sent to the image density control unit 103.

FIGS. 3B to 3F illustrate the scanner 101.
FIG. 5 is a diagram showing an example of image data obtained in step (a) and an image density setting value X set by the image density control unit 103 based on the image data. For example, if the number of standing bits is 19,
Let X = 3. The relationship between the number of bits and the image density setting value X is
Determined in advance by experiments and stored as a table,
In the image density control unit 103, the number of standing bits is detected, a required image density set value X is obtained by table search, and an image density set value T preset by the user is calculated.
If X ≦ T, this X determines that one of the photosensitive drums 106
The output voltage of the high voltage circuit 105 is controlled so as to determine the next charging potential.

The operation will be described below with reference to the flowchart of FIG. This process is performed by a CPU (not shown). The image density is set to T in advance by the user (S1). In this state, when double-sided print data is input from the host computer to the printer, the paper feed roller 10
7, paper feed is started (S2), and the paper 104 reaches the transport roller 108, and as shown in FIG.
4 intercepts the scanner 101 and the pattern plate 102 (S3). At this time, scanning by the scanner 101 is started (S4), and the read data is sent to the image density control unit 103. The image density controller 103 counts the number of standing bits from this data (S5). Here, if the data is in the state of FIG. 3C, that is, the scanner data (2), the number of standing bits a = 19.
-8), image density X = 3 is provisionally set (S7-8). Next, this set value X = 3 is compared with the originally set image density T (S8). At this time, if the image density set value X is T
If it is larger, the image density is set to T (S1).
0), otherwise set the image density to X (S)
9). The high voltage circuit 105 is controlled by the set value,
The potential of the surface of the photosensitive drum 106 changes, and the image density is in a proper state (S11).

As described above, in this embodiment, the hard copy without the transmission from the rear surface at the optimum image density is obtained by adjusting the image density by examining the transmission of the image from the rear surface to the paper surface using the scanner. can get.

If the image density setting value X is larger than the preset value T, the processing is performed assuming that the user has forcibly set the lower density T.

(Embodiment 2) FIG. 4 is a diagram showing a configuration of a main part of a "printer" according to Embodiment 2. In FIG. 4, 4
02 is a light emitting element such as an LED (light emitting diode), 40
Reference numeral 1 denotes a light receiving element whose output current varies depending on the amount of light (light intensity) of a phototransistor or the like. In FIG. 4, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Further, since the approximate operation is the same as that of the first embodiment, only the parts different from the first embodiment will be described.

In the first embodiment, the degree of transmission of the image on the paper 104 is detected by using a scanner and a pattern plate. In the present embodiment, the degree of transmission is detected by using a light receiving element 401 and a light emitting element 402. The current value generated by the light receiving element 401 while the paper 104 is being conveyed over the light emitting element 402 is detected (S24). It is determined in which range of the detected current value Ia the vertical axis of FIG. 6 falls, and the set value of the image density is provisionally set. If X ≦ T with respect to the image density set value T set in advance by the user, this set value X is permanently set, the high voltage circuit 105 is controlled, the potential of the photosensitive drum 106 changes, and the image density is appropriately controlled. Is done.

As described above, the present embodiment can provide the same effects as those of the first embodiment.

(Embodiment 3) FIG. 7 is a diagram showing an example of a double-sided recording test print output by a "printer" according to the third embodiment. In the figure, reference numeral 701 denotes a recording area with an image density of 2; 702, a recording area with an image density of 4; 703, a recording area with an image density of 6; 704, a recording area with an image density of 8; Indicates that the recording on the back side with the image density 8 is transparent on the front side.

FIG. 8 is a diagram showing an example of a test print by a conventional method for comparison with the test print of the present embodiment. In the figure, reference numeral 801 denotes double-sided recording at an image density of 2; 802, double-sided recording at an image density of 4;
Denotes double-sided recording with an image density of 6, 804 denotes double-sided recording with an image density of 8, and 805 denotes that each test print is recorded on the back surface with the same image density.

FIG. 9 is a diagram showing a configuration of a main part of the present embodiment. Referring to FIG. 9, reference numeral 901 denotes an image density control unit that receives data from the operation unit 905 or the like and controls the high voltage generation circuit 902. 902 receives a signal from the image density control unit 901 and applies a voltage corresponding to the signal to the charging roller 903. A high-voltage generating circuit for outputting; 903, a charging roller for charging the photosensitive drum 904 with electric charge; 904, a photosensitive drum coated with a semiconductor whose electrical characteristics change by light irradiation; 906, light irradiation to the photosensitive drum 904; Scanner unit 90
7 is a main scanning synchronization signal.

FIG. 10 is an explanatory diagram of the image density. FIG.
, 1001 is the toner adhesion amount per dot when the toner density is 2 and 1002 is 1 when the toner density is 8
It shows the toner adhesion amount per dot.

Normally, the image density is controlled by changing the charge amount of the photosensitive drum to change the number of toner particles per dot as shown by 1001 and 1002 in FIG.

Here, when double-sided recording is performed with a high image density as shown by 1002, the recording on the back side is transparent to the front side, as shown by 803 and 804 in FIG.

Further, the conventional printer outputs the same image density for one page as shown in FIG. 8 when outputting one sheet of paper. 4; 802) can be obtained on the first sheet as early as possible, but in the worst case, it cannot be obtained unless the number of types of image density is output.

Therefore, when performing double-sided recording, as shown in FIG. 7, one side of the paper is formed into a plurality of areas 701 to 704 having sequentially different image densities in one direction, and the other side facing the plurality of areas. If a single test print with the same image density as the area on one of the opposing surfaces is output for each of the multiple areas, the optimum image density can be determined with only this test print, and this image density is set. By doing so, it is possible to obtain a hard copy of double-sided recording with an optimum image density. The output of this test print is sent to the image density controller 90.
1 is provided with a counter, the main scanning synchronization signal 907 generated from the engine side or the band end signal generated from the controller is counted, and when a certain value is reached, the image density setting value can be changed.

As described above, according to the present embodiment,
Based on one test print, it is possible to easily set an optimum image density for double-sided recording.

[0032]

As described above, according to the present invention,
At the time of double-sided recording, a hard copy having an optimum image density can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a main part of a first embodiment.

FIG. 2 is a flowchart showing the operation of the first embodiment;

FIG. 3 is an explanatory diagram of the first embodiment.

FIG. 4 is a diagram illustrating a configuration of a main part according to a second embodiment.

FIG. 5 is a flowchart showing the operation of the second embodiment.

FIG. 6 is an explanatory view of a second embodiment.

FIG. 7 illustrates an example of a test print according to a third embodiment.

FIG. 8 is a diagram showing an example of a test print by a conventional method.

FIG. 9 is a diagram showing a configuration of a main part of a third embodiment.

FIG. 10 is an explanatory diagram of image density.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Scanner 102 Pattern board 103 Density control part

Claims (6)

[Claims] 1. An image forming apparatus comprising: a light transmittance discriminating means for discriminating a light transmittance of a recording medium; and an image density setting means for setting an image density for double-sided recording based on a discrimination result of the light transmittance discriminating means. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein the light transmittance determining means includes a pattern plate and a scanner arranged so as to sandwich the recording medium. 3. The image forming apparatus according to claim 1, wherein the light transmittance determining means has a light emitting body and a light receiving body arranged so as to sandwich the recording medium. 4. An image density setting means for sequentially setting different image densities for one recording medium, and one surface of the recording medium is formed based on the density setting by the image density setting means.
A test print in which a plurality of areas having sequentially different image densities in one direction are formed, and a plurality of areas on the other surface respectively opposing the plurality of areas have the same image density as the image density of the one surface opposing each other. An image forming apparatus comprising: a test print forming unit configured to form an image. 5. The image forming apparatus according to claim 1, wherein the setting of the image density is performed by controlling the surface potential of a photosensitive member that forms an electrostatic latent image. 6. One surface of a recording medium is a plurality of regions having sequentially different image densities in one direction, and a plurality of regions on the other surface respectively opposing the plurality of regions are defined as a plurality of regions on one surface opposing each other. An image density setting method comprising: determining an appropriate image density based on a test print having the same image density as that of an area, and setting the determined image density.