Patent Application
20090046290
None
The present invention relates to electrophotography, particularly methods and apparatus for evaluating print quality during manufacturing or remanufacturing of printer, facsimile, and copier cartridges.
Toner and ink manufacturers and re-manufacturers evaluate print quality before releasing a new, revised, or improved product into the market. Specifically, they look for print quality features, such as uniformity, background, text quality, density, toner scatter, toner compatibility, toner fusability, and the like. Printer cartridge re-manufacturers clean, repair damaged parts, replace worn parts, and add toner. Printer cartridge re-manufacturers also often evaluate print quality to select a part they want to use in remanufacturing. For instance, printer cartridge re-manufacturers run various print quality tests to find the toner type, which when added to a cartridge would allow the cartridge to closely resemble the performance of the cartridge from an original equipment manufacturer (OEM).
Conventional methods for evaluating print quality include using an adhesive tape or using a person's finger. Test and reference prints are printed, and then an adhesive tape is adhered to each of the prints. Alternatively, a person would wipe his finger on each of the prints. The amount of toner that adheres to the adhesive tape or finger for each of the prints is then compared. It can be realized that the above conventional methods do not provide a quantitative, objective, and repeatable test method. For instance, the duration and amount of pressure being applied to the prints either by the tape or the finger is not controlled and would vary each time the test is conducted. Methods and devices for effectively evaluating print quality are desired and are addressed by the present invention.
The invention includes a method for evaluating print quality comprising providing a first paper; providing a second paper; providing a reference print sample; providing a test print sample; obtaining pre-rub densities of the first paper and the second paper or the reference print sample and the test print sample; providing a mechanical rub tester; rubbing the reference print sample with a first paper using the mechanical rub tester; obtaining post-rub density of the rubbed first paper or the rubbed reference print sample; rubbing the test print sample with a second paper using the mechanical rub tester; obtaining post-rub density of the rubbed second paper or the rubbed test print sample; and comparing the pre-rub and post-rub densities of the first and second papers or the rubbed reference print sample and the rubbed test print sample.
The above description sets forth, rather broadly, a summary of embodiments of the present invention so that the detailed description that follows may be better understood and contributions of the present invention to the art may be better appreciated. Some of the embodiments of the present invention may not include all of the features or characteristics listed in the above summary. There may be, of course, other features of the invention that will be described below and may form the subject matter of claims. In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part of this application. The drawings show, by way of illustration, specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
Before describing one of the methods, the order in which the steps are presented below is not limited to any particular order and does not necessarily imply that they have to be performed in the order presented. It will be understood by those of ordinary skill in the art that the order of these steps can be rearranged and performed in any suitable manner. It will further be understood by those of ordinary skill in the art that some steps may be omitted or added and still fall within the spirit of the invention.
The present invention includes methods and devices for evaluating print quality. Referring to
The present invention may also utilize a mechanical rub tester 6, which allows multiple surfaces to be controllably rubbed against each other. The mechanical rub tester 6 may rub the two surfaces with consistent pressure, speed, duration, or frequency. The mechanical rub tester 6 may include a platform 8 where a first sample may be positioned and a weighted sample mount 10 where a second sample may be positioned. The weighted sample mount 10 may be attached to a motor 12 that provides the driving force for rubbing the first and second samples against each other. The rub conditions may be predefined. For instance, the motor 12 may be programmed to execute a predefined number of rub strokes at a predefined speed considering the weight of the block and sample attached to the motor 12. The mechanical rub tester 6 may be a rub tester by Sutherland, which may be purchased from Danilee Corporation of San Antonio, Tex. The print density readings of the samples may be taken before being rubbed using the mechanical rub tester 6 and after being rubbed.
The print quality evaluation method of the present invention preferably includes the following steps, which are shown in the equipment preparation flowchart 14 of
At step 17, a blank template may be prepared for use in sizing any blank paper that may be used during the print quality evaluation. The blank template may be of the same size and material as the sample template. The sample or the blank template may be used by laying it on the sample or blank paper, tracing the edges of the template, and cutting the sample or blank paper along the tracing. The sample or the blank template ensures that consistent sample or blank prints are used throughout the print quality evaluation.
Next, at step 18, the rub tester conditions are preferably pre-programmed. For instance, the rub tester may be pre-programmed to execute a predefined number of rub strokes at a certain speed considering the weight of the block attached to it. In the preferred embodiment, the predefined number of rub strokes is ten (10) for all samples and blank papers. It can be appreciated that the print quality evaluation method of the present invention provides a consistent and repeatable evaluation method, as the manner in which the samples and blank papers are rubbed are highly controlled by having consistent number of rub strokes and by using weighted sample mounts that have predefined weights.
At step 19, one or more density evaluation areas are preferably defined. The density evaluation areas are the areas where the print quality evaluation system is configured to take print density readings. Referring to
Referring now to
With continued reference to
Referring now to
Next, using the rub tester 6, at step 26, the sized blank paper is preferably positioned on the weighted sample mount 10, which is then attached to the rub test motor 12. The sized reference print sample is preferably positioned on the platform 8 of the rub tester 6. The motor 12 may then be activated and allowed to execute the predefined number of rub strokes at a predefined speed discussed above. After the blank paper and the reference print sample are rubbed against each other, the blank paper and the reference print sample are preferably individually scanned through the scanner 2 to obtain the post-rub print density readings at the predefined density evaluation areas (step 27).
The preferred process 30 of obtaining pre-rub and post-rub print densities pertaining to the test print samples will now be discussed using
The gathered data may now be compiled and reported to a table 40 shown in
After the average print densities are calculated and reported in column 42f, the difference between the average post-rub density and the average pre-rub density may be calculated for the each of the first blank paper and the second blank paper. The differences are preferably reported in rows 46a and 46b. The differences can be expressed as a percentage of their respective average post-rub densities as shown in rows 48a and 48b. Portion 50 of table 40 indicates the difference in terms of toner fusability between a reference print sample and a test print sample. In the example shown, the toner fusability of the reference print sample and the test print sample only varies by 5%. A manufacturer or re-manufacturer may choose to accept or reject the cartridge part, cartridge, or toner used in generating the test print sample, depending on the criteria set. For instance, the re-manufacturer may set a criteria rejecting products having print density variance of over 5% against the OEM products.
The table 50 of
It can now be realized that the present invention provides a print quality evaluation method that would generate reliable and repeatable results. It can further be realized that the present invention also provides a print quality evaluation method that allows re-manufacturers to effectively compare their products' performance against those of the original equipment manufacturers. The print quality evaluation method allows re-manufacturers to set standards and implement a protocol to review their products' compliance with the standards. Finally, the present invention provides a much more efficient alternative to conventional methods of using adhesive tapes or fingers.
Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. For example, the number and the sizes of the density evaluation areas may be varied. The invention is capable of other embodiments and of being practiced and carried out in various ways. The invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the above description or as illustrated in the drawings.
