JPH08220817A - Automatic density adjusting mechanism - Google Patents

Abstract

PURPOSE: To improve density adjustment by means of an automatic density adjusting mechanism provided with an AE table and a density table so as to reduce the fine adjustment and the resetting of the AE in a micro reader printer, etc. CONSTITUTION: As to an image forming device utilizing an electrophotographic system which has a reading means obtaining original image density data, this automatic density adjusting mechanism previously storing a density table changing the setting of process condition so as to change printing density, and the AE table making the original density data obtained at the reading means correspond to the density table and selecting adequate density table setting in accordance with the original density data, and density volume changing printing density according to the density table in the case of being operated by a user; AE table correction data revising the AE table is provided, stored and held, a set value inputted by the user is compared with a value found from the AE table, and the AE table correction data is updated based on the deviation amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine and an image forming apparatus using an electrophotographic system, and more particularly to an automatic density adjusting mechanism for a micro reader printer.

[0002]

2. Description of the Related Art Conventionally, an automatic density adjusting mechanism (hereinafter, referred to as an AE mechanism) of a printer using an electrophotographic system uses a sensor such as a photoelectric conversion element to detect reflected light or transmitted light of a document image illuminated by a light source. ROM prepared in advance and in the main unit
The density table and the AE table stored in.

The density table is for changing the density of a print image by changing the combination of image forming process conditions such as image exposure amount and developing bias.

The AE table is for selecting an appropriate printer setting on the density table based on the document density data obtained from the sensor. When printing is performed using the automatic density adjusting mechanism, appropriate printing conditions are automatically determined for various originals. Since this AE table is set so that a standard print can be obtained from an average original, it may be too thin or too dark depending on the user's preference and the purpose of using the print.

Especially in the micro reader printer, due to the characteristics of the microfilm, even if the density value of the film is close, the thin line in the drawing or the like has a lower contrast than that obtained by photographing a normal character original, and the sensor In some cases, these differences cannot be distinguished from the read data alone. That is, when the microfilm shown in the drawing is printed using an AE table that is most suitable for a normal text original, the print density is thin and lines are faint. Therefore, there is a means of discriminating a fine film difference by using a high resolution sensor, but the cost is increased, the data arithmetic processing is complicated, and it takes time.

Therefore, there are printers that have a function of releasing the AE mechanism and switching to the manual mode and can print with arbitrary volume settings, and printers that have a fine adjustment function of the AE mechanism.

[0007]

However, in the above-mentioned conventional example, the AE table itself remains fixed, so that the following drawbacks occur.

When a reset operation is performed to restore the printer setting state to the default, manual setting and AE fine adjustment must be performed again.

There is also a method of changing the setting itself of the AE table, but it is not easy for the user to do, and adjustment work by a service person having specialized knowledge and skills is required.

Further, since the density table sets the optimum combination of image forming process conditions for each density original, if the density table is changed, the balance of the process conditions becomes unbalanced, or it becomes unnecessarily too thin or dark. This will affect the image characteristics of the printer, such as making settings that allow for excessive prints.

Therefore, an object of the present invention is to shift the evaluation criteria of the AE while keeping the image characteristics of the printer as it is, thereby reducing the operations such as fine adjustment of the AE and resetting after switching to the manual mode.

[0012]

In order to achieve the above object, in the first and second inventions, the data on the density table and the sensor when the AE fine adjustment or manual setting is performed at the time of printing. It is characterized in that the relationship with the data of the document image detected in step 1 is compared with the AE table, and the AE table correction data is updated based on the deviation amount. With the above configuration, the present invention reduces the deviation during AE printing in the subsequent printing.

The third invention of the present application is characterized in that it is possible to select whether or not the input value is reflected in the update of the AE table correction data according to the judgment of the user. As a result, in the third aspect of the invention, the AE table correction data is not updated with the data that was left over during misprinting.

[0014]

EXAMPLES Various examples of the present invention will be described below.

(First Embodiment) A first embodiment of the present invention will be described below.

The printer has a density setting operation section as shown in FIG. 3, and the density volume value display LED 1 displays the density volume value set in the manual mode by turning on the LED. The density adjustment key 2 is for changing the set value of the density volume, and when the key is pressed, the display of the density volume value display LED 1 changes and the print density changes. The AE key 3 has a built-in LED, and when the key is pressed, the print mode is switched. It goes off in the manual mode and lights up in the AE mode.

FIG. 9 shows the flow of signals during printing.
Now, as shown in FIG. 4, when the print mode is switched to AE and copying is started, photometry is first performed by the AE sensor 10. A density volume value is obtained from the AE table shown in FIG. 8 stored in the ROM 5 based on the data obtained by A / D converting the sensor output value. For example, if the output value of the sensor is 8, the density volume value is 5. If no value is set in the AE table correction data of the RAM 6, the process condition is obtained from the density table based on this value. A density volume is also stored in the ROM 5, and in the case of the density volume shown in FIG. 7, when the volume value is increased, the output of the developing bias is increased to darken the image. In this case, the setting of the developing bias corresponding to the density volume value of 5 is -400V. The control signal output from the CPU from these results is D / A converted, and a predetermined voltage is output from the developing bias power source 9.

With the above settings, the process in which the user determines that the density of the output print is light and the dark print is reprinted from the same original will be described below.

The user switches to the manual mode, sets the density volume value to 6 with the density adjustment key 2 as shown in FIG. 5, and makes a copy. At this time, photometry and density volume determination are performed as in the AE mode. In this case as well, since the original is the same, the density volume value is 5. The CPU compares the density volume value obtained from the AE table with the value input by the user from the density setting operation unit 11,
Calculate the AE table correction value. The difference is 1 here. Then, the AE table correction data is updated. This value is retained by the backup battery even when the power of the main unit is turned off. The flow of processing at this time is shown in FIG.

Next, when the print mode is selected to AE and a copy is made, the AE correction data in the RAM 6 is referred to when the photometry and the density volume value are determined, and the density volume considering the new correction data is obtained. Therefore, the proper print can be obtained.

(Embodiment 2) Next, a second embodiment of the present invention will be described by taking a printer having an AE fine adjustment mechanism as an example. The description of the same parts as those in the first embodiment will be omitted.

The printer has a density setting operation unit as shown in FIG. 3, and the user can finely adjust the AE evaluation result by the density adjustment key 2 even in the AE mode. Further, a registration key 12 for updating the AE correction data based on the fine adjustment value is provided.

When the print mode is selected to AE and copying is started, photometry is performed by the AE sensor. When the output data obtained by the sensor is 8, the density volume value is determined to be 5 from the AE table of FIG. At this time, the AE correction data is referred to, but since nothing has been set here, no correction is made, and the process condition corresponding to this density volume is selected from the density table of FIG.
Is set. That is, the developing bias of 400 V is set and printing is executed.

At this time, for example, a process in which the user judges that the print density is low and the print is retaken will be described below.

As shown in FIG. 6, when the density adjustment scale is shifted to the darker side by one step in the AE mode and printing is performed, photometry is first performed and the density volume value of 5 is selected by the AE table. Process conditions corresponding to a concentration volume value of 6 shifted by a fine adjustment with respect to the selected value,
That is, since the developing bias of 450 V is set and printing is executed, proper printing can be obtained.

When the user determines that the print finish is good, the AE correction data is updated based on the AE fine adjustment value by pressing the registration key after the copying is completed. If the fine adjustment is not appropriate, the AE correction data will not be updated unless the registration key is pressed. By referring to the AE correction data at the next execution of the AE mode, proper printing can be obtained without fine adjustment.
The flow of these processes is shown in FIG.

[0027]

As described above, according to the present invention, A
If the user once corrects the discrepancy between the output result and the user's desire when printing in E mode, the user can obtain a proper print without correction from the next copy. . Therefore, the trouble of correcting the density setting each time the printer is used and the number of miscopying are reduced,
Saves time and resources.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of Embodiment 1 of an automatic density adjusting mechanism according to the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the automatic density adjusting mechanism according to the present invention.

FIG. 3 is an exemplary view of an operation unit and a display unit of the automatic density adjusting mechanism according to the present invention.

FIG. 4 is an exemplary view of an operation unit and a display unit of the automatic density adjusting mechanism according to the present invention.

FIG. 5 is an exemplary view of an operation unit and a display unit of the automatic density adjusting mechanism according to the present invention.

FIG. 6 is an exemplary view of an operation unit and a display unit of the automatic density adjusting mechanism according to the present invention.

FIG. 7 is an exemplary diagram of a concentration table.

FIG. 8 is an exemplary diagram of an AE table.

FIG. 9 is a diagram showing a signal flow when printing by a printer.

[Explanation of symbols]

1 ... Density volume value display LED 2 ... Density adjustment key 3 ... AE key 4 ... C
PU 5 ... ROM 6 ... R
AM 7 ... A / D conversion 8 ... D
/ A conversion 9 ... Development bias power supply 10 ...
AE sensor 11 ... Concentration setting operation unit 12 ...
Registration key

Claims (3)

[Claims] 1. A light source for illuminating a document and a reading unit for obtaining document image density data, a density table for changing print density by changing process condition settings, and a document obtained by the reading unit. The density data and an AE table which associates the density table with each other are stored in the main body in advance, and an automatic density adjusting mechanism for selecting an appropriate density table setting according to the document density data obtained by the reading means, and a user operation. Then, in a copying machine using an electrophotographic method having a density volume for changing the print density according to the density table, it has AE table correction data for correcting the AE table, and a backup battery stores the AE table correction data. From the AE table, which is stored and retained, from the set value of the density volume entered by the user The comparator compares the value is because, on the basis of the shift amount, automatic density adjustment mechanism, characterized in that updating the AE table correction data. 2. A light source for illuminating a document and a reading unit for obtaining document image density data, a density table for changing print density by changing setting of process conditions, and a document obtained by the reading unit. An automatic density adjusting mechanism for pre-storing the density data and an AE table corresponding to the density table in the main body, and selecting an appropriate density table setting according to the document density data obtained by the reading means, and an automatic density adjusting mechanism. In a copying machine using an electrophotographic system having an AE fine adjustment mechanism capable of correcting the evaluation result of the AE table by a user's input, the AE table correction data for correcting the AE table is provided, and the AE table is corrected by a backup battery. When the table correction data is stored and retained and the automatic density adjustment function is used, the fine adjustment entered by the user Automatic density adjustment mechanism, characterized in that updating the AE table correction data based on the value. 3. The automatic density adjusting mechanism according to claim 1, wherein the user can select whether or not to reflect the input of the user in updating the AE table correction data.