JP2004219582A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that retains the fixing quality of an image that has a high proportion of image area. <P>SOLUTION: The image forming apparatus includes a fixing-speed control part 13 that counts the number of the pixels of an image to be outputted, and calculates the proportion of its image area from the ratio between the result and the paper to be outputted. In order to output the image having a high proportion of the image area, the control part 13 makes the fixing-and-conveying speed lower than that assigned to a normal proportion. The image forming apparatus includes a CPU1 that controls the fixing-and-conveying speed control part 13. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly to a fixing and conveyance control technique for forming an image having a high image area ratio.
[0002]
[Prior art]
There is a technology that measures the number of pixels of an output image, calculates an image area ratio from a ratio with an output paper area, and determines a control value of a fixing temperature based on the image area ratio (for example, see Patent Document 1). In addition, a technique for adjusting the amount of a release agent in a fixing unit using an image area ratio has been proposed (for example, see Patent Document 2).
[Patent Document 1] Japanese Patent Application Laid-Open No. 09-114308 [Patent Document 2] Japanese Patent Application Laid-Open No. 06-175457
[Problems to be solved by the invention]
However, if the amount of the release agent increases, the amount of the release agent adhering to the paper or the transfer member also increases, adversely affecting the output image and causing other problems such as the necessity of cleaning the transfer member. Further, the fixing temperature changes slowly, and it takes time to complete the adjustment.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of maintaining a fixing quality for an image having a high image area ratio.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 measures the number of pixels of an output image, calculates an image area ratio from a ratio with an output sheet, and outputs an image having a high image area ratio. The main features of the image forming apparatus are a fixing speed control unit for lowering the fixing conveyance speed than usual and a CPU for controlling the fixing speed control unit.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the main feature is an image forming apparatus in which a fixing conveyance speed can be set arbitrarily.
According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the degree of the image area ratio when adjusting the transport speed after measuring the image area ratio can be arbitrarily set. And
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, when it is determined that the image area ratio is high, a predetermined number of sheets or more of images having the image area ratio or more are considered in consideration of the number of sheets to be passed. The main feature of the image forming apparatus is to determine whether or not to change the fixing conveyance speed when is performed.
According to a fifth aspect of the present invention, in the image forming apparatus of the fourth aspect, the main feature is that the fixed number of sheets can be arbitrarily set.
According to a sixth aspect of the present invention, in the image forming apparatus according to the first aspect, when the image area and the number of images are recognized, the obtained information is provided with steps within a certain range in the obtained information.
According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth aspect, when the image area is classified into a plurality of stages and the image area is recognized, the adjustment of the fixing conveyance speed is automatically performed in a corresponding plurality of stages. The main feature is the image forming apparatus.
According to an eighth aspect of the present invention, the image forming apparatus according to the seventh aspect is characterized in that the adjustment of the plurality of steps according to the plurality of steps can be arbitrarily set.
According to a ninth aspect of the present invention, in the image forming apparatus of the fourth and seventh aspects, a main feature is that the image forming apparatus can arbitrarily set whether or not to change the fixing speed.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, a CPU 1 controls each unit of the apparatus according to a program in a ROM 2 to execute processing of the present invention. The ROM 2 stores a basic program, a processing program of the present invention, and the like. The RAM 3 has a work area formed therein and stores various data necessary for controlling the apparatus. The scanner 4 reads a document. The plotter 5 performs copying and printing of a received document.
The operation display control unit 6 inputs an operation from the user and transmits information to the user. A communication control unit (CCU) 7 exchanges a facsimile control signal with a partner image forming apparatus and executes a facsimile communication procedure. The modem 8 modulates a transmission signal and demodulates a reception signal. A SAF (Store AND Forward) memory 9 stores images.
An encoding / decoding unit (DCR) 10 encodes the image information according to a predetermined encoding method, and decodes the encoded image information. A network control unit (NCU) 11 controls a communication line. The network interface control unit 12 controls a network. The fixing speed control unit 13 recognizes the image area ratio and adjusts the fixing unit conveyance speed. The above-mentioned units are connected to each other by a bus 14.
[0006]
FIG. 2 is a flowchart showing a control operation in the image forming apparatus of the present invention. At the start of image output (S1), the fixing speed controller 13 measures the image area ratio of the output image by counting the pixels and considering the paper size to be used simultaneously (S2). If the value of the image area ratio is equal to or larger than a preset value, it is determined that the image is a high area ratio image. If there is no other setting, the fixing speed control unit 13 sets the conveying speed of the fixing unit to a preset conveying speed and performs output.
If the setting is made in consideration of the number of sheets passed (No in S3), the fixing speed control unit 13 measures the number of sheets of the high area ratio image simultaneously with the measurement of the image area ratio. When the number of passed sheets exceeds a preset number, the fixing speed control unit 13 changes the conveyance speed of the fixing unit. There should be many combinations of the area ratio and the number of passed sheets in the high area ratio image. If more detailed speed control is set, the fixing speed controller 13 sorts them into a plurality of stages in consideration of these settings. For example, an image having an image area ratio of what percentage is called how many sheets are passed.
In this case, the fixing speed control unit 13 sets the conveying speed suitable for the stage using the respective conveying speeds in a plurality of stages set in advance, and adjusts the conveying speed of the fixing unit. When outputting an image that does not satisfy the above determination, the fixing speed control unit 13 sets an ordinary conveyance speed and performs image output (above, S4 to S10).
Specifically, when an image with a high image area ratio is output, the fixing conveyance speed is reduced, so that a margin is provided in the contact / separation time between the output image and the fixing unit, and the winding around the fixing unit can be prevented. It becomes.
[0007]
In addition, by arbitrarily setting how high the image area ratio is determined to be, it is possible to perform adjustment according to the fixing characteristics of each machine.
In addition, when adjusting the fixing conveyance speed when the image area ratio is high, by setting the number of sheets to be passed, the conveyance speed can be made as normal as possible and the productivity can be improved.
Also, by adjusting the number of sheets passed arbitrarily, it is possible to set the required number of sheets for speed adjustment, and by making settings in consideration of the characteristics of each machine, it is possible to improve productivity more suited to the machine. Can be achieved.
Further, when recognizing the image area and the number of images, by providing a step in a certain range in the obtained information, even if the image area ratio is high, how many images having the area ratio are output are output. Can be recognized.
When the image area is recognized in a plurality of stages, the fixing speed is automatically adjusted in a plurality of stages in accordance with the adjustment, so that the fixing conveyance speed at an appropriate speed is automatically adjusted according to the image area ratio. It becomes possible to select it.
Further, by setting necessary and sufficient speed change values at each stage of the image area, it is possible to perform optimal adjustment.
Since it is possible to arbitrarily set whether or not to change the fixing speed, it is possible to arbitrarily select whether or not to change the speed based on more detailed measurement classification.
[0008]
【The invention's effect】
As described above, according to the first aspect, at the time of outputting an image having a high image area ratio, the fixing conveyance speed is reduced, so that there is a margin in the contact / separation time between the output image and the fixing unit. Winding can be prevented.
According to the second aspect, the fixing conveyance speed can be changed to an appropriate state.
According to the third aspect, by arbitrarily setting how high the image area ratio is determined to be, it is possible to perform adjustment according to the fixing characteristics of each machine.
According to the fourth aspect, when adjusting the fixing conveyance speed, by setting the number of sheets to be passed, the conveyance speed can be made as normal as possible and the productivity can be improved.
According to the fifth aspect, it is possible to set the required number of sheets for performing the speed adjustment, and it is possible to improve the productivity more suitable for the machine by performing the setting in consideration of the characteristics of each machine. Become.
According to the sixth aspect, it is possible to recognize how many images having an area ratio are output even among images having a high image area ratio.
According to the seventh aspect, it is possible to automatically select a fixing conveyance speed at an appropriate speed according to the image area ratio.
According to the eighth aspect, it is possible to perform an optimal adjustment by setting a necessary and sufficient speed change value in each stage.
According to the ninth aspect, it is possible to arbitrarily select whether or not to change the speed based on more detailed measurement classification.
[Brief description of the drawings]
FIG. 1 is a block diagram of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a control operation in the image forming apparatus of the present invention.
[Explanation of symbols]
1 CPU
13 Fixing control section

Claims (9)

Measure the number of pixels of the output image, calculate the image area ratio from the area ratio with the output paper, and, when outputting an image having an image area ratio higher than a predetermined value, set the fixing conveyance speed to be lower than normal. An image forming apparatus, comprising: a fixing speed control unit for controlling the fixing speed; and a CPU for controlling the fixing speed control unit. 2. The image forming apparatus according to claim 1, wherein the fixing conveyance speed can be arbitrarily set. 2. The image forming apparatus according to claim 1, wherein the degree of the image area ratio when adjusting the transport speed after measuring the image area ratio can be arbitrarily set. 4. The image forming apparatus according to claim 3, wherein when it is determined that the image area ratio is high, the number of sheets to be passed is taken into account at the same time, and when a certain number of sheets or more of images having the image area ratio or more are passed, fixing is performed. An image forming apparatus for determining whether or not to change a transport speed. 5. The image forming apparatus according to claim 4, wherein the predetermined number can be set arbitrarily. 2. The image forming apparatus according to claim 1, wherein when recognizing the image area and the number of images, the information obtained is provided with a step within a certain range. 6. The image forming apparatus according to claim 5, wherein when the image area is recognized by being classified into a plurality of stages, the adjustment of the fixing conveyance speed is also automatically performed in a plurality of stages. . 8. The image forming apparatus according to claim 7, wherein the adjustment of the plurality of stages according to the plurality of stages can be arbitrarily set. 8. The image forming apparatus according to claim 4, wherein whether or not to change the fixing speed can be arbitrarily set.

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